_handoff

Motorola Confidential Proprietary

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1.0 Definitions 7

2.0 Issues and Solutions 12.1 Hard Handoff after Soft Handoff 13

2.1.1 Background 132.1.2 DAHO Trigger Review 13

2.2 AHHO Trigger 142.3 Seam Location 142.4 Optimization Strategy 152.5 AHHO Enhancements 182.6 Estimating Post-Seam HHO Performance2.7 Joe’s Bullets 192.8 Inter-CBSC and Inter Carrier Hard Handoff 2

2.8.1 Use of Pilot Beacon 212.8.2 Use of Frequency Hopping Pilot Beacon 22.8.3 Traffic Planning 212.8.4 DAHO 212.8.5 PrimeCo Chicago Proposal 22.8.6 Hong Kong Configuration 22

2.9 Inter-CBSC and Inter Carrier Soft Handoff 22.9.1 Use of Pilot Beacon 272.9.2 Use of Frequency Hopping Pilot Beacon 2

2.10 InterCBSC and Intra Carrier Hard Handoff 22.10.1 Traffic Planning 292.10.2 DAHO 29

2.11 InterCBSC and Intra Carrier Soft Handoff 32.12 IntraCBSC and Inter Carrier Hard Handoff 3

2.12.1 Use of Pilot Beacon 332.12.2 Use of Frequency Hopping Pilot Beacon 32.12.3 Traffic Planning 332.12.4 DAHO 33

2.13 IntraCBSC and Inter Carrier Soft Handoff 32.13.1 Use of Pilot Beacon 352.13.2 Use of Frequency Hopping Pilot Beacon 3

2.14 IntraCBSC and Intra Carrier Hard Handoff 32.14.1 Traffic Planning 372.14.2 DAHO 37

2.15 IntraCBSC and Intra Carrier Soft Handoff 3

3.0 CDMA Handoff Deployment & Optimization 413.1 Summary 413.2 Statement of the Problem 43.3 Scope and Audience 413.4 Organization 413.5 Definitions 413.6 Hard Handoff General Operation 4

3.6.1 General Operation 41

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3.7 Pilot Beacon 423.7.1 Intra-Carrier Hard Handoff Optimization 42

3.8 Intra-Carrier Hard Handoff Deployment Tips 43.9 Inter-Carrier Hard Handoff With Pilot Beacons (Multi-Carrier) 43.10 Inter-CBSC Hard Handoff With Pilot Beacons 43.11 DAHO and Inter-CBSC Soft Handoff 46

3.11.1 Single Cell Intra-Carrier Hard Handoff 43.11.2 Dual Cell Intra-Carrier Hard Handoff 46

3.12 Nondominant PN 493.13 Idle mode handoff 513.14 PN Planning 55

3.14.1 micro-cell 553.14.2 in-building 55

3.15 Neighbor Window Search Planning 83.16 Microcell 83

3.16.1 When to Deploy 833.16.2 Intercarrier issues 83

3.17 InterVender Hard Handoff 853.17.1 IS-634 85

3.18 InterVender Soft Handoff 873.18.1 IS-634 87

3.19 Customer Specific Issues 83.19.1 KTF 893.19.2 Hong Kong MTR 893.19.3 Singapore 89

3.20 HHO as soon as One-Way 93.21 CDMA Soft Handoff Optimization 93

3.21.1 Introduction 933.21.2 General Mechanics of Soft Handoff 93.21.3 Mobile Station/Base Station Data Analysis 103.21.4 General Conclusion 105

4.0 Present Tools 1274.1 Pilot Beacon 1294.2 Qualcomm solution 1294.3 Motorola solution 129

4.3.1 Integrated Solution 1294.3.2 Stand alone solution 1304.3.3 Paging and Sync Channel Requirements 14.3.4 how to set up paging and sync channels to redirect idle mode mobiles

5.0 CDMA Pilot Beacon Applications 1335.1 Scope 1335.2 Objective 1335.3 PILOT BEACON CONCEPT OVERVIEW 1335.4 PILOT BEACON DEPLOYMENT SCENARIOS 134

5.4.1 Scenario A: Inter-Carrier HHOs for Partial Overlay Multi-Carrier 1

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5.5 Scenario B: Pilot Beacon to Perform Inter-CBSC Hard Handoffs5.5.1 Primary Deployment Option (“Spot Beacon” Approach) 15.5.2 Requirement for Broadcasting Pilots in all Beacon Sectors

5.6 KNOWN LIMITATIONS 1405.6.1 Idle Mode Handoffs 1405.6.2 Mobile Re-direction with CDMA Channel List Message 145.6.3 Mobile Behavior with Loss of Service 1415.6.4 Recommendations 141

5.7 Subscriber Capacity Limits 1425.8 IMPLEMENTATION 142

5.8.1 Hardware Requiremets 1425.9 Installation and Optimization 1435.10 Beacon Span Requirements 145.11 REFERENCES 1435.12 SC-2.5.1 Pilot Beacon Installation 14

5.12.1 BTS Modifications - Beacon Settings 145.12.2 BTS Calibration File Description. 1465.12.3 Step-by-step procedure to change Bay Level Offsets with Script:

5.13 Database Provisioning 145.13.1 GENERAL ADD SECOND CARRIER COMMANDS 1475.13.2 Mobile Programming 1495.13.3 Source Database Configuration 145.13.4 Neighourlist Additions 1495.13.5 External Sector Topology 1495.13.6 Optimization Techniques 151

6.0 Idle Handoff Solution Description 1556.1 Idle Handoff Equipage Procedural Detail 156.2 Pilot Beacon Output Power 156.3 Expectation for Empirical Results 156.4 Static Simulator 1596.5 Partial Overlay 161

7.0 FutureTools 1637.1 Frequency Hopping Pilot Beacon 167.2 N-Way SHO and Complex SHO (Barry’s paper or parts thereof7.3 Umbrella Cell 2097.4 Six Sector 2117.5 DAHO optimization strategies 2137.6 Back To Back Antennas 2157.7 Mobile Specification Changes 217.8 Nokia/Qualcomm contribution. 2177.9 DeClerck/Ashley improvements. 217.10 Pilot Dominance 2237.11 Complex Handoff 2257.12 Edge Sensing 2657.13 Description and discussion. 26

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7.13.1 Tune TADD/TDROP/TTDROP to force the mobile into less soft-handoff. 27.13.2 Design the frequency seam using natural topological features, such as rivers, larg

tracts of land (less clutter).2657.14 E911 techniques which may be used for hard-handoff detection.

7.14.1 Bruckert/Ghosh/ et. al. developments. 27.14.2 DeClerck/Harris improvements. 26

8.0 Background 2698.1 CDMA Hard Handoff Problems & Solutions 27

8.1.1 Hard Handoff Topics 2718.1.2 IS-95A Pilot Definitions 2718.1.3 Pilot Status Transitions 2718.1.4 Pilot Strength Measurement Message 28.1.5 Pilot Scan Algorithm 2728.1.6 Pilot Scanning Basics 2728.1.7 Pilot Scan Algorithm Implications 2728.1.8 The Hard Handoff Problem 2738.1.9 Multi-Carrier Handoff (“Wedding Cake” Example) 278.1.10 “Spot Capacity Relief” Example 2738.1.11 Hard Handoff Algorithm 2738.1.12 Intra-Carrier Hard Handoff 2738.1.13 Pilot Beacons (Inter-Carrier Hard Handoff) 278.1.14 Pilot Beacon Deployment (Inter-CBSC Handoff Example) 28.1.15 Pilot Beacon Deployment (Multi-Carrier Example) 278.1.16 Pilot Beacon Optimization 2758.1.17 Idle Mode Handoff Problems 2758.1.18 Idle Mode Handoff Solutions 2768.1.19 Capacity With Pilot Beacons 2778.1.20 Additional HHO Solutions Under Study/Consideration 28.1.21 Edge Sensing (DAHO) 2788.1.22 DAHO Deployment 2798.1.23 Edge Sensing (Ec/Io Thresholding) 278.1.24 Edge Sensing (Ec/Io Thresholding Example) 28.1.25 CDMA Scan Receivers 279

8.2 Moving the Selector 307

9.0 Release Schedule 319.1 Release 5 3119.2 Release 6 3119.3 Release 7 3119.4 Release 8 3119.5 Release 9 3119.6 Release 10 311

10.0 Competition 313

11.0 Summary 32111.1 CDMA to Analog (AMPS/NAMPS/TACS) handoff, same service provider 311.2 N carriers to N-1 carriers handoff (CDMA carrier handoff). 3

11.2.1 Extra carrier for In-building or tunnel, spot coverage. 3

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11.2.2 Extra carrier for large scale changes in population density (Urban to suburban/ Suto Rural)321

11.2.3 Notes on systems that have older non-adjacent frequency scanning mobiles.11.3 Intersystem seam (where the Carrier bands do not intersect)

12.0 Vision 32312.1 Timeline 323

13.0 System’s Engineering Recommendations 313.1 Criteria for Successful Feature Deployment and Operations:13.2 New CDL format: 32513.3 Trouble-Shooting Guide: 32613.4 Inter-CBSC Planning Guide: 3213.5 Inter-CBSC Application Note: 32613.6 ATP for the Inter-CBSC SHO: 32613.7 Inter-CBSC Customer Presentation: 3

14.0 Bibliography 329

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1.0 Definitions

New terms for microcells and umbrella cells.

AHHO: see Anchor Hard Handoff

Anchor Hard HandOff. A technique used in R7 CBSC software to transfer transcoder control from oneCBSC to another CBSC after successful inter-CBSC soft handoff. The need for AHHO is deemed to be ter-mporary in nature as future software functionality will obviate the need for AHHO by allowing subsequentCBSC seam and multi-carrier transitions. R7 software needs the AHHO to allow CBSC seam and multi-carrier transitions, etc.

Cell Swapping : An algorithm in the infrastructure that works with Partial N-Way SHO and actually per-forms reverse link handoff (switching an XC connection) from one cell (BTS) to another. It is an operationsimilar to Fast Pilot Shuffling, however performed at the BTS, rather than PN, level.

Cell Swapping : The exchange of all legs between a mobile and one BTS with one or more legs to a BTSnot currenlty serving the mobile.

Complex Handoff: A handoff instruction to the mobile station which makes more than one change to the

mobile’s active set.[3]

DAHO: see Data Base Assisted Handoff.

Data Base Assisted Handoff: handoff techniques that use information on cell configuration stored in theCBSC/BTS along with the system’s knowledge of which cells/sectors control a particular call. DAHO tech-

niques may be used to trigger hard handoffs.[3]

Fast Pilot Shuffling . Also known as “FPS”, a technique used in R5, R6, and R7 whereby T_TDROP tim-ers for active set pilots are preempted only in three way SHO when in the presense of a candidate set pilotthat meets the shuffle criteria. Fast Pilot Shuffling does not discriminate between soft and softer connec-tions.

Full Complex Handoff : This feature implies the ability (on the part of the infrastructure) to perform multipleadd and/or drop operations within one Extended Handoff Direction Message. Because of the desire, at thetime of Extended Handoff Direction Message transmission to utilize the maximum number of currentlyavailable forward and reverse links for the procedure transaction, this also implies 2N forward/reverse linkswhere N is the maximum expected size of the active set.

Full Complex Handoff: The infrastructure’s ability to perform a complex handoff with the maximum num-ber of legs being changed that is allowed by the IS-95 Air Interface Specification. (During the full complexhandoff, the infrastructure should use all of the old legs and all of the new legs. For example, if the mobilehas 3 legs and the infrastructure wants to replace 1 of the legs with 2 different legs, the infrastructureshould use the 3 currently active legs and on the 2 new legs. If the mobile can support N legs, the infra-structure should support 2N legs during the full complex handoff.)

Full Diversity N-Way : This feature implies everything contained with “Full N-Way” as well as subscriberunit hardware with N demodulation elements.

Full N-Way : This feature implies XC hardware able to support 6 forward and 6 reverse links. Uses “NextGeneration” or “improved” XCDR circuitry that supports the ability to manage 6 MCCce’s.

HHO. Hard HandOff.

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HHO Complex : Also known as “complex HHO”, this feature implies the ability on the part of both sub-scriber unit and infrastructure to connect the subscriber unit into at least 3-way soft/softer handoff immedi-ately at the target following an Extended Handoff Direction Message. Thus, N forward links are transmittingas the subscriber unit performs connection procedures at the target.

Infrastructure Assisted Pilot Dominance : This feature implies a handoff algorithm on the part of theinfrastructure that examines active set and candidate set pilot Ec/Io estimates in the Pilot Strength Mea-surement Message and attempts to determine an optimal active set while simultaneously minimizing thenumber of forward link transmitters to the minimum required for quality forward link reception.

Leg: A communications path between the infrastructure and a mobile that uses one PN offset and oneWalsh code in the forward direction.

MAHO: See Mobile Assisted Handoff

Mobile Assisted Handoff: handoff techniques that use measurements made by the mobile and returned

to the BTS. MAHO techniques may be used to trigger soft, softer and hard handoffs.[3]

Mobile Assisted Pilot Dominance : This feature refers to the recent Qualcomm proposal of using a sec-ondary threshold that is a function of the sum of the active set SNRs as a technique to inhibit Pilot StrengthMeasurement Messages. See appendix #B for clarification of the Qualcomm proposal.

Non-Dominant PN . This is a condition defined by good/excellent RF coverage (non-thermal noise limitedcase, >-80 dBm) with poor pilot Ec/Io performance. Also described by some in the industry as “pilot pollu-tion”.

Partial Complex : This feature implies those complex operations that may be accomplished by utilizingexisting XCDR hardware. These operations are defined by the Jim Aldrich matrix and constrained by thenumber of forward and reverse links required to complete any given handoff operation1.

Partial N-Way : This feature implies the ability to support up to 6 forward (Walsh codes) and 3 reverselinks2. Uses currently available XCDR circuitry. Forward links are a mix of soft and softer connections suchthat we are always constrained to 3 reverse links.

SHO. Soft HandOff.

Soft Handoff: a state where a mobile station is communicating with two or more cell sites simulta-

neously.[3]

Soft Shuffling . A technique used with Partial N-Way SHO whereby a pilot at one BTS is swapped out infavor of another, superior performing, pilot at another BTS. Both BTSs currently serve the subscriber unit.

Soft Shuffling . A technique used with Partial N-Way SHO whereby a pilot at one BTS is swapped out infavor of another, superior performing, pilot at another BTS. Both BTSs currently serve the subscriber unit.

1. As an example, consider the situation where a subscriber unit is in 3-way SHO between 3 different BTSIf we wanted to simultaneously add a new BTS while dropping one of the existing BTSs, we’d still wanto transmit theHandoff Direction Message via the transmitters of the 3 existing BTSs and receive theHandoff Completion Message via the receivers of the 3 new BTSs. Due to current downlink combiningtechniques, we can’t just decide to drop a transmitter from the active set without first informing the subscriber unit, etc.

2. If the combining bit in theExtended Handoff Direction Message is used, then the mobile only responds to3 sets of PCG puncture bits.

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Softer Handoff : similar to soft handoff except that two of the cell sites involved are sectors of the same

cell.[3]

Softer Handoff: two or more legs of a call are to the same cell.

Softer Shuffling . A technique used with Partial N-Way SHO whereby a pilot at one BTS is swapped out infavor of another, superior performing, pilot at the same BTS.

Softer Shuffling: A handoff that involves adding or removing legs that are in softer handoff. An old leg isremoved before a new leg is added.

TADD: When operating in the TAdd mode, any time a pilot rises above the TAdd threshold or the TCompthreshold (i.e. a pilot has risen TComp ¥ 0.5dB above any active set pilot), the system will attempt to add

that pilot to the mobile station’s active set via a soft or softer handoff.[3]

TAdd (Database Parameter): The threshold above which a pilot must rise in order for the MS to transmit apilot strength measurement message. The system sends this parameter to the mobile station in the RF:System Parameters Message, RF: Extended Handoff Direction Message, and the RF: In Traffic System

Parameters Message.[3]

TCOMP: When operating in the TComp mode, a pilot must rise above the TComp threshold before the

system attempts to add it to the mobile station active set.[3]

XASECT (database parameter): eXternal Analog SECTor

XCSECT (database parameter): eXternal Cdma SECTor

TComp (Database Parameter): The threshold which a candidate set pilot strength must rise above anactive set pilot to cause the MS to transmit a pilot strength measurement message. The system sends thisparameter to the mobile station in the RF: System Parameters Message, RF: Extended Handoff Direction

Message, and the RF: In Traffic System Parameters Message.[3]

TDrop (Database Parameter): The threshold below which a pilot strength must drop in order for the MS totransmit a pilot strength measurement message. The system sends this parameter to the mobile station inthe RF: System Parameters Message, RF: Extended Handoff Direction Message, and the RF: In Traffic

System Parameters Message.[3]

TTDrop (Database Parameter): The amount of time in seconds the MS will allow an active or candidateset pilot strength to remain below the drop threshold before action is taken to remove the pilot from theactive or candidate set. The system sends this parameter to the mobile station in the RF: System Parame-ters Message, RF: Extended Handoff Direction Message, and the RF: In Traffic System Parameters Mes-

sage.[3]

HandOffMode (Database Parameter): Specifies to the XC which handoff mode to use. Currently twomodes are defined. TAdd mode and TComp mode. TAdd mode tells the system to add a pilot to a call assoon as it crosses the TAdd threshold. TComp mode tells the system to wait for a pilot to rise above the

TComp threshold before it is added to a call. This data exists in the XC database, not in the MIB.[3]

PilotInc (Database Parameter): The mobile station uses this field to determine how remaining set pilotsshould be searched. It is set to the largest increment such that the pilots of the neighboring sectors areinteger multiples of the increment. This data is sent to the mobile station in the RF: Neighbor List Message

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and the RF: Neighbor List Update Message. The XC must use the same value as is contained in the

MIB.[3]

NeighborList (Database Parameter): This list contains all of the neighbor sector PN offsets for the cur-rent call. This parameter is passed to the XC in both the SCAP: CDMA Update Parameters Message and

the SCAP: CDMA XC Channel Assigned Message.[3]

DAHO (Database Parameter): This parameter indicates whether a sector-carrier is near a border andcontains neighboring or overlapping sectors operating on another frequency and/or non-CDMA signalling

scheme.[3]

DAHOHysTimer (Database Parameter): This parameter is used to prevent ‘ping-pong’ handoffs betweentwo sectors which have been marked with the DAHO flag. After a hard hand-in, origination, or terminationin a border sector, majority border checks will be disabled for a period of time in seconds equal to the value

of this parameter.[3]

HandoffMethod (Database Parameter): This parameter specifies the method (none, hard, soft trunking,soft aplus) to be used to hand the call off to a sector external to the CBSC. The scope of this parameter is

per external CDMA sector.[3]

Inter-CBSC Soft Handoff Override (Database Parameter): This parameter is used to ‘turn-off’ Inter-CBSC soft handoffs between two MMs. It is checked by both source (in handoff detection) and target pro-cedures. When override is allowed, the alternative action of either no handoffs or hard handoffs is indicated

(no handoffs, hard, no override). The scope of this parameter is per inter-CBSC trunk group.[3]

AnchorHoMeth (Database Parameter): this per CBSC parameter indicates the condition upon which trig-ger the source MM to move a mobile in Inter-CBSC soft handoff from a source (or ‘anchor’) MM to a targetMM once all the source legs have been dropped (keep soft, on no source legs, on all legs remote). Theparameter can be used to keep calls in soft handoff, to execute a hard handoff when there are no sourcelegs in the call, and to execute a hard handoff when all the legs are remote, i.e. no known XCSECT repre-

sentations in the source CBSC.[3]

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2.0 Issues and Solutions

Each sub-section in Section 2.0 contains a problem description and a solution.

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2.1 Hard Handoff after Soft Handoff

The Release 7 form of inter-CBSC soft handoff requires that some calls go through ahard handoff. This hard handoff is alternatively known as “post seam HHO” or “AHHO”(Anchor Hard HandOff). This document describes how to minimize the impact of the hardhandoff.

This document describes optimization strategies for improving the performance of theAHHO.

2.1.1 Background

2.1.1.1 Hard Handoff Problem Description

The hard handoff is required to move the selector function (the software/hardware thatselects the best reverse link VCELP frames to be converted to PCM) from one CBSC toanother. See Section 8.2, “Moving the Selector,” on page 307.

2.1.1.2 Anchor HHO and DAHO - Database Assisted HandOff

DAHO uses cell configuration information stored in the CBSC/BTS along with the sys-tem’s knowledge of which cells/sectors control a particular call. DAHO is typically used totransition calls from one CDMA carrier to another (intra-CBSC case) or from a CDMAcarrier to an analog carrier (AMPS, NAMPS, TACS).

The AHHO (associated with ICBSC-SHO) is similar to DAHO in that the trigger criteria isequivalent. In addition, the target selection (antenna) criteria is identical in that the stron-gest active set pilot Ec/Io in the most recent Pilot Strength Measurement Message isused. The departure between AHHO and DAHO is that AHHO is always intra-carrier innature. DAHO is always inter-carrier in nature.

2.1.2 DAHO Trigger Review

The DAHO handoff detection criteria is described in Section 7.5, “DAHO optimizationstrategies,” on page 213. Note that the handoff is driven off of a table that describes thenumber of soft handoff legs supporting the call from “handout” sectors (i.e. “border sec-tors”). These sectors can also be omni-directional cellsites. Note also that the targetselection portion of the DAHO algorithm allows inter-cell hard handoff, however this is notthe preferred method. The preferred method uses an intra-cell hard handoff to a singlesector. The target is chosen from the current active set pilot list using that active set pilotthat demonstrates the “best” performance. “Best performance is defined by the strongestEc/Io measurement in the most recent Pilot Strength Measurement Message prior to sat-isfaction of the detection criteria.

Based upon the above trigger criteria, and the target selection criteria, it is easy to spec-ulate that the “safest” post-seam HHO (Hard HandOff) occurs on a soft handoff dropevent when the active set is reduced from 2 active pilots to 1 active pilot. In this scenario,there is no ambiguity as to which target will perform best after the HHO as the target“range” is limited to a single pilot.

Based upon the previous reasoning, it is also easy to speculate that the poorest perform-ing post-seam HHO occurs upon completion of a pilot shuffle operation. In this particular

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scenario, there exist at least1 3 active set pilots that could potentially be used to desig-nate a target sector. In situations where all pilots perform equally well and with excellentFER margin, there is little probability of losing the call. More than likely, this will not be thecase, and the system engineer will be presented with additional optimization tasks toattempt to improve the success of the handoffs.

2.2 AHHO Trigger

AHHO trigger criteria is somewhat similar to that of DAHO. The criteria for triggering theAHHO occur when:• No active set pilots originate from the “anchor-side” of the CBSC seam.

• No active set pilots originate from XCSECT sectors within the target CBSC that are associated with the “aside” of the CBSC seam.

The purpose of the two trigger criteria is to provide the system designer with tools to cre-ate an inter-CBSC “hysteresis region”. It should be the obvious intent of the systemdesigner to minimize AHHO operations2. Consider Figure 1 below for a case of a sub-scriber unit moving from left to right. AHHO is triggered when no active set pilots sup-porting the call originate from either the “clear” or “striped” cells in the diagram. Thisimplies that all active set pilots, at the time of AHHO, originate from the “spotted” cells inthe diagram. Note that one of the “spotted cells” would be the (1-Way) target of theAHHO.

Figure 1: Simplified AHHO Seam Construction Layout

2.3 Seam Location

1. Note that plans currently exist for implementation of N-Way SHO (SoftHandOff) where N will be greaterthan 3. This is expected to further complicate the situation being described.2. This is due to the fact that any type of HHO has inherent risk relative to soft handoff operations. At thetime of this writing, SHO success rate is nominally greater than 99.5% while HHO success rate (Pilot Becon, inter-carrier) is deemed to be on the order of 92%-97%.

CBSC #1 CBSC #2 Key

CBSC #1 “anchor-side” cell

“XCSECT” cell for CBSC #1

CBSC #2 Cell(Not “XCSECT” cell for CBSC #1)

CBSC Seam

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The primary goals of the AHHO deployment should be to simultaneously minimizethrashing of the A+ interface (and related switching equipment) while minimizing thenumber of RFLOSSs associated with AHHO. Due to the “width” of the target CBSCregion, it might not be possible to implement a hysteresis region to suppress ICBSC-SHO “ping-ponging”. Thus, the former goal might be sacrificed in favor of the latter goal.

It is inevitable that the system designer will be presented with some number of patholog-ical situations that are vexing in terms of optimality of seam placement. There may beconstraints due to CBSC traffic loading, frequency planning, BTS/CBSC span backhaulor microwave concerns, or others. Given that none of these constraints is present, andthat the designer has freedom to choose, selection criteria should be based upon the fol-lowing list:• Gradual pathloss roll-off.

• Deployment restricted to “large” cells only1

• No quick NLOS to LOS or LOS to NLOS transitions.

• No low altitude antenna placements that increase the likelihood of NLOS to LOS (or vice versa) transition

• No seams in areas of weak RF coverage.

• No seams in areas of non-dominant PN.

• Avoid “distant” soft handoff connections where some probability exists of selecting the “distant” cell as theof the DAHO. This has to do with slew rate by the subscriber unit if the reference pilot needs to be changbelow).

2.4 Optimization Strategy

DAHO (Database Assisted HandOff) uses cell configuration information stored in theCBSC/BTS along with the system’s knowledge of which cells/sectors control a particularcall. There are a host of issues that the system designer must be cognizant of whendesigning an inter-CBSC SHO system. The following is a non-comprehensive list ofsome issues that should be considered. Seam optimization is, no doubt, a multi-variableoptimization problem. The sensitivity of the problem to any particular variable is probablylocation specific. It is up to the system designer to understand the issues pertinent to his/her own market and prioritize these issues in rank order appropriate to the circum-stances2 of that market.• The RF system performance of power control and soft handoff across inter-CBSC seams. This topic is ad

in slightly more detail below. In general, we expect handoff and power control operations to be slower in thCBSC case than in the intra-CBSC case.

• Load-balancing or “re-parenting” of cells under CBSCs. This has to do with providing equal growth for N Cin the system under consideration. Sometimes, re-parenting causes inter-CBSC seams to placed in locaare ideal for load-balancing but non-optimal for RF performance, etc.

1. This begs the question of urban deployments of ICBSC-SHO. The intent here is to provide a “stable” sof Ec/Io measurements from which to base target selection. A high velocity subscriber unit moving througa set of micro-, or pico-, cellular structures might be subject to rapidly changing rank ordering of the activset Ec/Io measurements, causing lack of certainty in the target selection.2. These could be some combination of customer preferences, constraints due to physical facilities, (futuexperience with inter-CBSC SHO performance, etc.

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• AHHO mode performance.

• Trunk hardware and other possible transmission or interconnect facilities constraints.

• Proximity to “other” CBSC seams. See Joe Pedziwiatr’s Inter-CBSC SHO web page for further informatseam planning constraints relative to software capabilities in any given CBSC software release.

• Proximity to inter-carrier borders.

Our current assumptions regarding success of the DAHO procedure are as follows:• The algorithm will work poorly in regions identified as being “non-dominant PN”1.

• The algorithm will work poorly in regions identified as being poor, or marginal, in terms of RF coverage.

• The algorithm will experience difficulties in handling regions identified as having high utilization of the FastShuffling algorithm.

There are some techniques that the optimization engineer can use to enhance the suc-cess of DAHO. Some enhancement techniques may be limited by the amount of freedomassociated with repositioning antenna mounts. As an example, consider the engineerwho is faced with the difficulty of improving DAHO success rates while maintaining suc-cess rates for an analog service used by the same antennas, etc.

Some specific DAHO optimization tips/techniques:• Keep soft handoff longer with non-border cells (general case) or source CBSC pilots (ICBSC-SHO case

might be useful in those instances where the optomizer has observed that nominal DAHO procedures ardue to the location of the handoff. This technique strives to move the handoff location by prolonging connenon-border cells for a longer period of time, possibly to a location that is more advantageous to the DAHOrithm. The inverse of the situation would be to try and promote early handoff if this was desired. Both mmay be attempted by varying the T_TDROP timer and/or the value of T_DROP in the area2 of interest.

• Keep soft handoff longer with source CBSC pilots (ICBSC-SHO case): This has the benefit of allowing calltime terminate normally and avoid an AHHO altogether. Obviously, the technique where XCSECTs are ucreate a spatial hysteresis region works to much greater advantage in this case.

• Making areas of pilot dominance: Since the DAHO target selection process is dependent on Ec/Io measucontained within thePilot Strength Measurement Message, it makes sense that the success rate will be depenon . . . make the handoff drop occur, or make pilot dominance from the target perspective. As an exampsider target selection from a soft handoff state where several active set pilot Ec/Io’s are represented in Strength Measurement Message. The resulting target connection reliability would look something like tgram below.

1. The term “pilot pollution” has also been used, however this term is largely less descriptive as the real rson for non-dominant PN is the amount, or volume, of CDMA “noise” in the area of interest. Only a portionof this noise is due to actual pilot signals.2. When in soft handoff, the CBSC chooses values for T_ADD, T_DROP, T_TDROP, and T_COMP fromamongst all the cells in soft handoff. Thus, the optomizer needs to be aware of exactly which cells suppothe call prior to DAHO attempts. For more detail regarding selection of MAHO parameters when in SHO,consult the Handoff and Power Control SFS.

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i-r

Figure 2: Target Reliability as a function of active set Ec/Io

• Making soft handoff connections to cells that provide better diversity for theExtended Handoff Direction Mes-sage: In some small number of circumstances, it may be that the cause of DAHO failure is inability the subunit, to correctly decode theExtended Handoff Direction Message. In general, these areas should have previoubeen optimized for soft handoff, and this particular problem should appear at low rates. Change soft parms.

• Making soft handoff connections to cells that avoid significant subscriber unit slew activity in the event threference pilot is changed because of the DAHO target selection. This could possibly result in some latensubscriber unit sending preamble frames on the uplink at the target. The specification currently calls for mum of two contiguous successful forward link frames at the target before the subscriber unit re-enables hmitter to send preamble (as an example, see section 2.6.6.2.8 of J-STD-008). Thus, we have the expecttiming slew should have ceased by then in those instances where the reference pilot changes1. Note however thatboth IS-95A and J-STD-008 specify a slew rate range of 3/8 chip per second (slowest) to 1.25 chips per(fastest).

• Since AHHO takes place after completion of soft handoff drop or pilot shuffling operation, the PSMM migon the order of 0.5 to 1.0 seconds old (“stale”) by the time the information is used for target selection. This that the handoff areas need to be stable2, non-multi-pilot areas if possible. In the worst of all scenarios, re-paring or cells under a CBSC (AHHO case) or moving of inter-carrier boundaries might be warranted.

• PCS optimization might be easier than cellular optimization in that the PCS engineer has more latitude ining antenna patterns3 to create coverage or pilot dominance.

1. It’s not really clear to me exactly what the subscriber unit does for timing correction as far as hard handis concerned. At one time, CSS claimed they would “snap” to the new reference immediately and bypass slew rate numbers quoted in the specification. Since the specification is vague, it’s anybody’s guess whaQualcomm, Samsung, Oki, Nokia, Japanese vendors, etc. will do.2. An example of a “non-stable” pilot region might be an area where line-of-sight with a cellsite is impedeby several buildings creating a “picket fence” pattern of pilot Ec/Io for that site. Disaster occurs when thetarget selection is performed when the subscriber unit is illuminated by the target site and then executioncompletes when the subscriber unit is shadowed from the target site.3. Obviously within reason. There are limits to the amount of antenna adjustment in both vertical and horzontal planes specifically for the purposes of optimization of ICBSC-SHO before problems appear in othefunctionality.

Active Set Ec/Io“Delta” dB

Targ

et C

onne

ctio

n R

elia

bilit

y

of 20


. only 1

repre-thresholdyst be at

at theing, or

eesr

2.5 AHHO Enhancements

At this writing, an enhancement is being proposed for the R7 release of inter-CBSC thatis thought to improve the target selection portion of the AHHO. The enhancement basi-cally treats the above mentioned AHHO triggers as “AHHO trigger enablers” and goes onto further specify new trigger criteria. There are two new trigger criteria:• AHHO trigger on any soft handoff operation that leaves the subscriber unit in a 1-way connection state (i.e

active set pilot).

• AHHO trigger on any soft handoff operation where the “imbalance” between active set pilot Ec/Io’s (as sented in the Pilot Strength Measurement Message) is above a certain threshold. For R7, the imbalance will be specified by using the T_COMP parameter1. Thus, in order to trigger the AHHO when in 2-way or 3-wasoft handoff, the differential (in dB) between the strongest active set pilot and any other active set pilot muleast T_COMP dB before the handoff is triggered/executed.

2.6 Estimating Post-Seam HHO Performance

The figure below demonstrates the correlation between origination and DAHO proce-dures. The intent is to draw attention to the similarities between the two.

Some number of connections that attempt DAHO will be 1-way connections. As long asthese are not coverage limited scenarios, their success rate should be quite high.

As good as originations?Figure 3: Origination and DAHO Procedure Comparisons

• Some probability that target sector/pilot will also be reference sector/pilot.

• Some probability that the AHHO will never occur as call may terminate normally. This is due to the fact thbeacon handoff would always have occurred. Also, the mobile has some very small probability of stoppeven turning around, before AHHO.

1. Unfortunately, this presents the system designer/optimizer with the trade-off dilemma between using thT_COMP parameter for optimization of soft handoff and AHHO. While a separate parameter that decouplthe two functions was desirable, it was not possible for the software organization to deliver this in time foR7.

Mobile Origination Pr ocedure DAHO Procedure

Idle mode cell selection

Mobile Origination Message

Channel Assignment Message

1-Way Connection at target

Active Set pilot rank ordering

Pilot Strength Measurement Message

Extended Handoff Direction Message

1-Way Connection at targetTime

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See my slides!!!!2.7 Joe’s Bullets• Notes on Ec/Io statistics fromPilot Strength Measurement Message.

• HHO terms from Barry’s slides.

• New terms for microcells and umbrella cells.

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2.8 Inter-CBSC and Inter Carrier Hard Handoff2.8.1 Use of Pilot Beacon

2.8.2 Use of Frequency Hopping Pilot Beacon

2.8.3 Traffic Planning

2.8.4 DAHO

2.8.5 PrimeCo Chicago Proposal

As of 6/5/97, PrimeCo Chicago uses “bands” of alternating carriers as shown in Figure 4.

With the addition of another CBSC, the configuration will look like Figure 5.

These configurations provide isolation between like carriers. They also maximize thenumber of Pilot Beacons between the CBSCs as the coverage areas are long and nar-row. CBSC-2s coverage area is roughly 2 to 3 cells wide.

PrimeCo now needs multiple carriers because of call traffic. They also need to start con-figuring their system for Release 7 which has InterCBSC SHO. The Release 7 version ofSHO requires three layers of BTSs to complete the SHO which presents a problem withnarrow coverage areas.

CBSC-1, F2

CBSC-4, F2

CBSC-2, F1

Figure 4: June 1997 PrimeCo Chicago Configuration

Lake

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The Hong Kong Systems Engineers have tested? a configuration shown in Figure 6. Thisstrategy uses the Pilot Beacon frequency to carry traffic between the beacons.

The drawbacks with this configuration are:

1. The reduction in the number of carriers available to carry traffic at the seam

2. Two hard handoffs to cross a seam.

To minimize these drawbacks, the number of BTSs within the seams should be maxi-mized while minimizing the number of BTSs on the seam. This requires a circular config-uration.

Figure 7 shows a PrimeCo Chicago configuration that meets the objectives of minimizedseam cells and multiple carriers. CBSC-2’s coverage area would be made as large aspossible and still handle the load until Release 7 is available. A large coverage area mayallow the border with CBSC-1 to be at a low traffic area.

2.8.6 Hong Kong Configuration

Author: Lau Patrick Q13187 at icid

Date: 2/20/97 22:27

CBSC-1, F2

CBSC-4, F2

CBSC-2, F1

Figure 5: Late 1997 PrimeCo Chicago Configuration

Lake

CBSC-3, F1

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Priority: Normal

TO: Cheng TakLok Q12466M at #EMAIL

F1 PPS+TCH

F2 PPS+TCH

CBSC #1 CBSC #2

F1 PPS+TCHF1 Beacon (PPS)

F2 Beacon (PPS) F2 PPS+TCH

Figure 6: Wall-To-Wall Pilot Beacon


F1 Beacon (PPS)

CBSC #3

CBSC-1, F2

CBSC-4, F1

CBSC-2,F1 & F2

Figure 7: Late 1997 PrimeCo Chicago Configuration

Lake

CBSC-3, F1

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TO: Ip Tim w10691 (Ip Tim W10691C)

TO: Tse Thomas CHK010 (Tse Thomas CHK010c)

TO: Dubberstein Steve CLXR04 at #EMAIL

TO: Chan Joe Q12656M at #EMAIL

TO: Chan Simon Q12202M at #EMAIL

TO: Kwok Dragon q12753 at #EMAIL

TO: Cheng Clement Q12472

TO: Wu William Q13681

TO: Ng WaiKeung Q12436

TO: Tong Simon W10557C at KT_PO

TO: Cheng Raymond Q12056c at KT_PO

TO: Chan KitWing Q12397 at KC_PO

TO: Wong Alex Q12457

CC: Ngan S.K. Q11669 at #EMAIL

Subject: Implementing Pilot Beacon with 2 Traffic carrier

Abstract

Based on Hutchison’s CDMA system requirement, there will be a needfor the HK CDMA system to support 120 - 150k with the current Rel 5

software. However, in order to have a good handover success rate acrossthe CBSC boundary, Pilot beacon seems to be the only solution at the

moment. Nonetheless, it seems like we cannot utilise this approach with 2traffic carrier right now. However, with a different setup in the database, it

has been proven that we can idea have a 2 traffic carrier system whileusing the beacon approach.

2.8.6.1 Database setting requirement

1. Configure Frequency F1 = 241 and F2 = 283 for one CBSC while the neighbor-ing CBSC(s) will have F1 = 283 and F2 = 241. This change will require an outagefor the entire CBSC and its related sites.

2. All the cage mapping including paging, sync, and access channels must bechanged such that the first cage will always be transmitting the primary frequency.This will require site outage should we elected to do this on a site by site basis.

2.8.6.2 Hardware/Calibration requirement

1. All cages need to be calibrated for a range of frequencies rather than one singlefrequency. This will allow us to reconfigure different cages to transmit at differentfrequencies more flexibly. With the calibration procedure right now, it seems wecan only guarantee to have clean CDMA carrier for one single frequncy per cage.

of 26


2. Need to ensure both cages are functioning properly and traffic channel cardsare balanced between different frequencies in order to allow us to swap transmis-sion frequency if required.

2.8.6.3 Systems engineering issues

1. All second cages must be verified and the degree of load sharing between dif-ferent carriers must be monitored.

2. CBSC Boundary must be defined beforehand based on traffic pattern. This willallow both the database and hardware to be re-located properly before implemen-tation.

3. After cage remapping, call test must be performed to ensure that the right cageis transmitting the right frequency.

2.8.6.4 Advantages

1. Reduction/Removal of Intra -CBSC inter carrier hard handoff : Currently, wehave to set our database such that those sites residing in the same CBSC mustdo hard handoff into a beacon site. This will no doubt create some dropped calls.By using the beacon carrier as a handoff only carrier, intra cbsc inter carrier hardhandoff is no longer required for those calls live in the same cbsc handing into thebeacon sites.

2. Blocking reduction : Blocking (origination and termination) has been recordedfor many of the beacon sites since its implementation, we suspect that this is dueto the Mobile origination algorithm. In having traffic channels for the beacon sites/sectors, this problem may possibly go away.

3. Advantage of Pilot Beacon from the RF perspective can still be maintained asmost users will cross the boundary through an intercarrier approach.

4. Partial loading reduction for the non beacon carrier : Since handoff traffic canstill be allowed to access the beacon carrier, loading on the non beacon carriercan be reduced. This can directly increase the capacity of our system especiallyfor those stationary or calls with low mobility.

2.8.6.5 Tradeoff

1. It seems only allowing users to access the Non beacon carrier will create someimbalance between the carriers. Hardware installation and re-adjustment may benecessary prior to implementation, creating some simple but extra hardware anddatabase reconfigurations due to boundary movement.

2. On crossing the boundary, users using the beacon carrier will experience oneintra carrier, inter CBSC Hard handoff first before he can be settled into a strongernon beacon carrier. This will no doubt in increasing the chance drop call. However,we need to evaluate the extent of this issue through some field trial later.

3. The beacon carrier will remain as soft handoff target mainly. Should Hutchisondecide to take the risk, we have the option to allow this beacon to be used as fulltraffic carrier while minimising the impact of intra carrier hard handover.

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2.8.6.6 Conclusion

Since the implementation of this setup will require participation from all of the Hong Kongoperation departments. Each party should study the time frame involved and individualneeds e.g. practice on database preparation, call testing and verification of channel infor-mation. Nonetheless, all effort involved for this change could well prove to be worthwhilein meeting many of the Hutchison demand.

Regards

Patrick

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2.9 Inter-CBSC and Inter Carrier Soft Handoff2.9.1 Use of Pilot Beacon


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of 28


2.10 InterCBSC and Intra Carrier Hard Handoff2.10.1 Traffic Planning

2.10.2 DAHO

of 30


of 30


2.11 InterCBSC and Intra Carrier Soft Handoff

of 32


of 32


2.12 IntraCBSC and Inter Carrier Hard Handoff2.12.1 Use of Pilot Beacon


2.12.3 Traffic Planning

2.12.4 DAHO

of 34


of 34


2.13 IntraCBSC and Inter Carrier Soft Handoff2.13.1 Use of Pilot Beacon


of 36


of 36


2.14 IntraCBSC and Intra Carrier Hard Handoff2.14.1 Traffic Planning

2.14.2 DAHO

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of 38


2.15 IntraCBSC and Intra Carrier Soft Handoff

of 40


of 40


3.0 CDMA Handoff Deployment & Optimization

3.1 Summary

With planning of hard handoff location and careful selection of hard handoff parameters,the negative impacts of inter-CBSC hard handoffs can be minimized.

3.2 Statement of the Problem

The early versions of CBSC software do not support inter-CBSC soft handoff whichforces the use of hard handoffs between CBSC boundaries. Similarly, no CDMA vendorscurrently support inter-vendor soft handoffs which forces hard handoffs between CDMAvendor boundaries. Moving a call from one carrier to another carrier requires a hardhandoff.

Hard handoffs cause audio interruptions and increased dropped call rates in the hardhandoff regions. To minimize audio interruptions and dropped calls, the hard handofflocation and parameters must be carefully planned.

Motorola currently the following solutions to the hard handoff problem:

- Pilot Beacon (in development)

- Database Assisted HandOff (in development)

- XSect

- Intra-Carrier, Intra-Cell

3.3 Scope and AudienceThis document provides general hard handoff guidelines to Motorola Systems Engineers.

3.4 OrganizationThe next section defines terms used in this document. After the definitins, the hard

handoff operation is described. Following that, each of Motorola’s hard handoff solutionsare described.

3.5 DefinitionsHard Handoffduring a call, the mobile station drops all if it’s current RF connections to the

infrastructure, possibly retunes it’s synthesizer to another carrier, and reestablishes atleast one RF connection with the infrastructure. The audio path is interrupted between the

dropping of the original paths and reestablishing the new paths. (Compare with SoftHandoff.)

Inter-carrierbetween two different carriers. For example, handing off from F1 in Cell A toF2 in Cell B.

Intra-carrierwithin the same carrier. For example, handing off from F1 in Cell A to F1 inCell B.

Soft Handoffadding and subtracting RF connections during a call between the mobilestation and the infrastructure without interrupting the audio.

3.6 Hard Handoff General Operation

3.6.1 General OperationIntra-carrier hard handoff detection is accomplished when the CBSC receives a Pilot

of 48


lated-ating the on val-

late in

ments ofime-rate-

ing on theo forces to par-mes will

, it is

rst is tothe seam

Strength Measurement Message that reveals a candidate pilot (which is an XSECT in thedatabase) appears T_COMP dB above all active set pilots. When this happens, a targetchannel is set up in the target CBSC and then the mobile is instructed (via the Extended

Handoff Direction Message) to change the active set pilot(s). T_COMP is used as avehicle for hysteresis in the process with the amount of hysteresis proportionate to the

value T_COMP is assigned.

3.7 Pilot Beacon

3.7.1 Intra-Carrier Hard Handoff Optimization

Given the philosophy above, the implications are that successful hard handoff is a strongfunction of the deployment methodology. See below for more details. In addition, thereare several other factors which affect the success rate of hard handoff.• T_COMP parameter: The Qualcomm mobile station demonstrates poor sensitivity (relative to simu

expected) in the seam region, especially at slow speeds. Thus, the amount of hysteresis used in comb“ping-pong” phenomenon must selected with care. In some instances, it may be that T_COMP cannot takeues any greater than 0.5 dB.

• Mobile station latency: Qualcomm has communicated to us that all versions of mobile station software arereporting T_COMP events via thePilot Strength Measurement Message. The quickest that a mobile will respondwith such an event is 250 milliseconds after the change has occurred in the RF domain. Lab measurev1.34 and v1.60 phones indicate that the delay might be 2 to 3 times as long. Thus, situations where the tof-change of the interfering pilot (i.e. target pilot) is large should be avoided.

• Infrastructure latency: Just as in soft handoff, there is a certain amount of processing and message passpart of the CBSC that must occur upon each hard handoff execution. In addition to this, hard handoff alsthe MSC and target CBSC to be involved as well. Future versions of CBSC and MSC software will attemptallelize the handoff process to the greatest extent possible, however inter-CBSC hard handoff execution tiprobably never be below 500 milliseconds.

• Extended Handoff Direction Messagesuccess rate: Given the discussion on mobile station sensitivity aboveapparent that successful delivery of theExtended Handoff Direction Message to the mobile station is difficult in“high-noise” regions (i.e. the seam). There are a few things that can be tried to help this situation. The fikeep forward traffic channel gains as high as possible, and perhaps even at their maximum values, in

BTS 1 BTS 2

F1 Traffic Channels

F1 Pilot Beacon

CBSC 1 CBSC 2

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ount of

resentide of aat wouldells, itntil thendoff

s.

isec-ber of

e slight

n in

Cairn

s.

due to

the caseiversity”

itionf sec-

by

cells. This only works in low noise, low traffic conditions. The second is a drastic measure where the ampower devoted to the paging and synchronization channels is reduced, or even eliminated.

• Multiple handoff regions: Due to the nature of radio-wave propagation, it is possible that scenarios will pthemselves that allow for multiple handoff regions along a line, or road, separating two cellsites on either sCBSC seam. Some handoffs may be completely unnecessary in the sense that a propagation condition thtrigger a hard handoff comes and goes very quickly due to mobile (vehicle) movement. For fairly large cmay be possible to use the neighbor search window to make the mobile station “blind” to the target pilot umobile is well within the overlap region1. Once again, care must be taken in using this parameter as soft hawith cells/sectors on the same side of the CBSC seam is dependent on the value that the parameter take

• Number of L2 repeats: The current intra-carrier hard handoff algorithm specifies four “salvos” ofExtended Hand-off Direction Message attempts. The number of “salvos” will soon be increased to 7. Each “salvo” is 320 millonds long2 and contains a number of attempts equal to the L2 Num_Repeats count. Increasing the numrepeats from 3 (default?) to 6 (maximum “sensible” value) may increase the message delivery rate in somway.

3.8 Intra-Carrier Hard Handoff Deployment TipsIn general, successful intra-carrier hard handoff deployment is characterized by:

• Gradual pathloss roll-off.

• Deployment restricted to “large” cells only.

• No quick NLOS3 to LOS4 transitions (target cell(s)). An example of this would be the Tai Po Harbor situatioHK.

• No quick LOS to NLOS transitions (source cell(s)). An example of this would be the situation in Tate’s Tunnel in HK where the entrance is blocked by a large vehicle and the source cell “goes away”.


• Cells far enough apart to make use of neighbor search windows to help in suppression of ping-ponging.

• Seams placed perpendicular to high traffic flow.

• No seams parallel to high traffic flow.

• No seams in high traffic areas.

• Seams in areas where traffic moves with relatively high speed such that the probability of ping-pongingextended "straddling" of the handoff zone is reduced.

• Preferably one to one or many to one transitions. By this, we mean a single target cell. We all agree thatof being in soft handoff at the source cell(s) is advantageous in that we can use the site-to-site “macrodside benefit of SHO to assist in increasing the probability that theExtended Handoff Direction Message will bedelivered successfully5. Unfortunately, going in the opposite direction, you’d have a situation where the transis one to many - definitely a situation we’d like to avoid. It might be that conditions would allow the usage o

1. As a special note, DSD is considering basing hard handoff detection upon phase measurements madechannel elements. While solutions of this type might fall into the “tractable” category, their implementationis not in the near term.2. See IS-95A section 6.6.4.1.3.2 and the value for timer T3m.3. Non-line-of-sight.4. Line-of-sight.5. The “Fast Pilot Shuffling” feature will allow us to specify lower values for the T_ADD parameter in theseam cells. This should increase the probability of 2-way and 3-way soft handoff in those border cells inwhich the topology favors pilot coverage at T_ADD Ec/Io’s.

of 48


the bor-

of HHOas the

imited”.

torized sites at the CBSC borders to make the target cells unambiguous and to limit the amount of SHO atder.

• Deployment scheme that makes use of natural or man-made terrain features to either limit the number transitions or limit the amount of “other cell noise” coupling between the two CBSC service areas. This wtactic that the HK team was using (look at an elevation map of HK).

• No sector boundaries for a cell that cross high volume traffic paths in expected handoff locations.

• No seams in areas of weak RF coverage. The seam area should be “interference-limited” and not “noise-l

• Seams should be optimized for soft handoff

3.9 Inter-Carrier Hard Handoff With Pilot Beacons (Multi-Carrier)

:

3.10 Inter-CBSC Hard Handoff With Pilot Beacons

Path of mobile station

BTS 1 BTS 2

F1 Traffic Channels F1 Pilot Beacon F2 Traffic Channels

Trigger Point

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Figure #8.) Ideal Inter-CBSC Hard Handoff With 4 RF Carriers (R5)

The figure below shows the solution that the Hong Kong account team is proposing. Notethat carrier F1 is ubiquitous in the system due to the IS-95 “Primary” CDMA channel

requirement. In addition, 1/2 of all handoffs (assuming symmetrical mobility and carrierdistribution per CBSC) are intra-carrier in nature.

Figure #9.) Hong Kong R6 Inter-CBSC Solution


F2 PPS+TCH F2 Beacon (PPS)



CBSC Seam

CBSC #1 CBSC #2

F1 PPS+TCH



CBSC Seam

CBSC #1 CBSC #2

F1 PPS+TCH

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3.11 DAHO and Inter-CBSC Soft Handoff

3.11.1 Single Cell Intra-Carrier Hard HandoffThis memo serves to provide general guidelines regarding deployment of intra-carrier

(same RF carrier), inter-cell (between 2 different cells) hard handoff. Motorola currentlysupports this type of handoff in an effort to preserve active calls that traverse (different)CBSC service areas. The items in this memo are, to a great degree, common sense,

however some are gleaned from practical experience in our Hong Kong market. Note that“seam” in this discussion designates an area where handoff needs to take place between

two different CBSCs.In general, intra-carrier hard handoff performance is not as good as that of soft/softer

handoff. DSD is working on the problem, however no tractable solutions have presentedthemselves. This should not be communicated to the customer.

3.11.2 Dual Cell Intra-Carrier Hard Handoff

Mony Hassid’s idea.

From: Menich Barry on Wed, May 7, 1997 9:30 AM

Subject: Mony Hassid Disclosure - May '97

To: Hulsebosch Tom

Cc: Bonta Jeff; Bruckert Gene; Campbell Neal; Kotzin Mike; Frank Miller; Jim AldrichGWI; Kowalewski Rolf; Menich Barry; Schuler Joe; Welk John

Tom,

This is just a little note to lobby you for a favorable treatment of Mony Hassid's patent dis-closure for intra-carrier CDMA hard handoff up for review on the 15th. The business case

F1 PPS+TCH

F2 PPS+TCH

CBSC Seam

CBSC #1 CBSC #2



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here for Motorola is clear. This could be a stop-gap measure for some markets with inter-CBSC handoff problems caused by lack of spectrum (Korea? AirTouch?). The businessdownside is the need for some extra equipment, but as you know, we already have thatproblem (to some degree) with pilot beacons.

The technical merits of the disclosure will obviously be judged by the committee mem-bers at the time of the review. For what it's worth, my opinion is that this is a tractablesolution that requires no CBSC software modification and I support some kind of mini-trial somewhere (LA?). Mony already has some preliminary spreadsheet results and willfollow-up with some static simulation ideas.

In addition, I'm available for technical consultation with any of the committee membersthat want to discuss this.

-Barry

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3.12 Nondominant PN

of 50


of 50


beacon

vers the

3.13 Idle mode handoff

TO: PCS PrimeCo, Ltd.

FROM: Motorola CDMA Development Group

RE: Idle-mode Handoff Problem at CBSC Seams and Possible “Work-around”

CC: Graham Haddock, Maria Martinez, John Thode

As you know, Motorola’s solution to inter-CBSC handoff was an inter-carrier solutionutilizing pilot beacon hardware. Because of the particular implementation, idle-mode

handoff problems have been observed that cause lapses in system acquisition by thesubscriber unit. This memo outlines a possible near term “work-around” for the problem.

The “work-around” proposed has already been tested by another Motorola CDMAinfrastructure customer and appears to provide relief from some idle-mode handoff

problems associated with the inter-CBSC deployment.

Solution DescriptionThe nature of the solution involves a characteristic of the R5.1 CBSC software load that

requires that all carriers at a BTS/sector transmit identical parameter information onsynchronization and paging channels. In particular, the CDMA Channel List Message onthe paging channel and the Sync Channel Message body on the synchronization channelcan be used on pilot beacon carriers to force the subscriber unit to re-tune it’s frequency

synthesizer to the over-laid (non-beacon) RF carrier.Consider the simple diagram below (Fig. 1) which depicts hypothetical control flow for

subscriber unit idle-mode activity. CBSC #1 (cell #1) and #2 (cell #2) are to the left andright of the seam respectively. Traffic channel RF carriers F1 and F2 are also deployed tothe left and right of the seam respectively. A subscriber unit, in idle-mode, is traversing

the seam from left to right and is currently monitoring the paging channel for CBSC #1 onF1.

The sequence of events is as follows:• Subscriber unit monitors pilot Ec/Io and paging channel FER of current idle-mode active set1 cell (cell #1) on fre-

quency F1.

• Subscriber unit determines that coverage of current active set cell (cell #1) is no longer adequate and thatcell pilot (also F1) is superior in terms of Ec/Io.

• Subscriber unit changes active set pilot to beacon cell (cell #2) and monitors synchronization channel.

• Subscriber unit recovers the CDMA_FREQ field from the synchronizationSync Channel Message body.

• The subscriber unit then begins monitoring the paging channel (on F1) at the beacon site (cell #2) and recoCDMA_FREQ field from theCDMA Channel List Message body.

• Subscriber unit determines that such that a frequency retune is required.

1. J-STD-008 uses the identical terminology (e.g. “active set”, “neighbor set”, etc.) to describe both idle-mode and tch-mode pilots.

CDMA_FREQS CDMA_FREQR≠

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roniza-
• Subscriber unit retunes from F1 (beacon) to F2 (TCH bearing pilot) at cell #2 and begins monitoring synchtion channel, etc.
Figure #4 Subscriber Unit Traversing CBSC Seam

Equipage Procedural DetailGiven that the beacon sites are already provisioned, we will only have to add one

overhead MCC for each sector that is involved in the beacon hand-off. Below (in boldfont) is an example of commands that should be run in order to provision the new

overhead MCC's and alter the channel list:add sch-bts#-sector#-carrier#-sch#add pch-bts#-sector#-carrier#-pch#

Scan currentactive pagingchannel.

Start

Currentpaging channel coverage exhausted?

Obtainneighbor (F1 beacon) cell sample

Beaconcell coverage established (F1)?

No

Yes

No

Yes

No Yes

Scan other PNs, possibly other RF carriers.

Acquire new cellsynchronization channel

Acquire new cell paging channel

Current RFcarrier.EQ. RFcarrier inCDMA Chan List Msg?

Subscriber Unitcamps on beaconsignal (undesiredoutcome)

Subscriber Unitretunes to RFcarrier inCDMAChan List Msgand monitorssynch/paging

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(Do not provision an ach as we do not want the mobile to access the beacons.)

add mcc-bts#-sector#-mcc# SRCHAN0= SRCHAN1= SRCHAN2=0-0-0-0 SRCHAN3=0-0-0-0

SRCHAN4=0-0-0-0 SRCHAN5=0-0-0-0 SRCHAN6=0-0-0-0 SRCHAN7=0-0-0-0 MODE=ONEOCG

MCCTYPE=MCC8(By linking the srchan's to 0-0-0-0, the database is informed that we wish to add a card

without traffic channels, and will, in turn, inhibit all channel elements. This allows us to addthe card without using up valid timeslots.)

edit sch-bts#-sector#-carrier#-sch# link ce=bts#-mcc#-1edit pch-bts#-sector#-carrier#-pch# link ce=bts#-mcc#-0

(This will link the paging and sync channels to MCC.)edit carrier-bts#-sector#-carrier# channellist chan1=1 or 2 (depending on side)

If the site has traffic on F1 and the beacon is F2, then the above edit will link the channellistto F1. Conversely, if the site has traffic on F2 and the beacon on F1, then the edit will link

the channellist to F2.activate mcccutover mccenable mcc

There is a possibility that the MCC may not come INS. If that happens, it is most likely dueto the gli_dev_map not getting updated real-time. In order to "work-around" this problem

if it is seen, simply disable/enable the cage controlling gli (in this case, gli-3.)The above changes will link the beacon's channellist to the frequency of the traffic cageand allow the mobile to re-tune to the frequency specified in the message. In addition,

SyncCdmaFreq parameter in the Sync Channel Message will get set to the samefrequency as is specified in the Channellist Message. So, a mobile powering-up in the

zone could re-tune without having to acquire paging.

Pilot Beacon Output PowerSince the addition paging and synchronization channels to the beacon carriers will resultin an additional 2.67 dB of extra output power, it might be necessary in some situations toreassess beacon output power and adjust (upward) accordingly. The expectation is thatthis should be a rare occurrence given that beacon output powers in the PrimeCo markets

were adjusted by “feel” rather than by some analytical technique. Nevertheless, fieldengineers should be alert for undesirable changes in handoff locations. These changes,

should they occur, will most probably manifest themselves between beacon sites.

Expectation for Empirical ResultsThe desired result from deployment of this technique is quicker response time by the

subscriber unit in acquiring the synch/paging channels of the TCH-bearing RF carrier atthe target cell during a seam transition. With the current deployment, the Qualcomm

subscriber unit will attempt to scan all PN-space on the current carrier (while at the beaconsite) before aborting and retuning to another carrier for system acquisition attempts. Thishas been monitored by both customer and Motorola personnel and is estimated to take

of 54


nts.

no less than several seconds. During this period, the subscriber is inhibited from placingcall attempts or receiving pages.

Motorola’s recommendation is that 2 seam transition areas be identified for testingpurposes. One area would serve as a control for purposes of data comparison. The otherarea1 would be equipped with the relevant hardware and provisioned with synch/pagingchannels as discussed previously. The goal of any testing is to observe decreased system

unavailability of the Pilot/Page/Synch beacon sites relative to the Pilot-only sites.

CFC5 ProblemMotorola field engineers have observed that higher occurrence of CFC5 problems

appears to be associated with CBSC seams. Motorola is still investigating this problem,however one hypothesis offered attempts to explain the problem via the mechanism of the

“ping-pong” phenomenon associated with idle-mode scanning. The “ping-pong”phenomenon may be exacerbated by the lack of paging and synchronization channels in

the beacon sites.Because of the reduced beacon footprint relative to the over-laid TCH cell at the beaconsites, mitigation, or elimination, or idle-mode “ping-pongs” should place the subscriber unitwell within the reverse link range of the over-laid TCH cell and hopefully reduce the CFC5counts in these regions. There is, however, no guarantee that this will occur and Motorola

will continue to investigate.

1. If possible, the experimental area should be chosen from those seam cells that exhibit high CFC5 couSee next section “CFC Problem”.

of 54


3.14 PN Planning3.14.1 micro-cell

3.14.2 in-building

Sam Fernandez e-mail

of 56


of 56

DOCUMENT CLASSIFICATION:

MOTOROLA CONFIDENTIAL PROPRIETARYThis document and the information contained in it is CONFIDENTIAL INFORMATION of Motorola, and shall not be used, or published, or disclosed, ordisseminated outside of Motorola in whole or in part without Motorola’s consent. This document contains trade secrets of Motorola. Reverse engineering

of any or all of the information in this document is prohibited. The copyright notice does not imply publication of this document.

MOTOROLA INTERNAL USE ONLYThis document and the information contained in it is for INTERNAL USE ONLY for Motorola, and shall not be used, or published, or disclosed, or dissem-inated outside of Motorola in whole or in part without Motorola’s consent. This document contains trade secrets of Motorola. Reverse engineering of any

or all of the information in this document is prohibited. The copyright notice does not imply publication of this document.

MOTOROLA CUSTOMER CONFIDENTIALInformation contained herein is proprietary to Motorola and DSC, for whose benefit confidentiality shall be maintained.

Date: Version#: Supersedes Version#:

Location:

GENERAL CELLULAR INFORMATIONInformation contained herein is intended for use by Motorola and customers of Motorola (current or future).

ReviewedPreliminary Reviewed By:Inspected

PN Offset Planning

User Presentation

Samuel D. Fernandez

Abstract

This document provides an overview of factors impacting PN Offset Planning in a CDMASystem. The importance of the PILOT_INC parameter is explained.

June 17, 1996 1.0

HP -> /usr/test/adv_sys/cdma/documentation/stolen/fernandez/pn_planning

Revision History

1.0 06/17/96 Samuel D. Fernandez

• First Release - contains the presentation as it was made to BANM on June 4, 1996. This was afterpresentations to both PrimeCo and GTE. It is anticipated that further changes will be madeespecially in consideration of planning on a border.

of 80


■ Interference may occur for an active set pilot. This interferencein the ‘active’ area and involve the active search window (SRCH

■ A neighbor set pilot may falsely appear strong enough for the Mthe pilot to the candidate set and recommend to the BS to phandoff ‘add’ via the PSMM. This ‘falsing’ would occur in the ‘nand involve the neighbor search window (SRCH_WIN_N).

■ A signal may travel far enough so as to be incorrectly identifiewhen it translates the MS reported phase into a PILOT_PN.

Consequences of poor offset planni n

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The possible sources of interference and falsing include the ‘co’ and adjacent offsetIn analog, co-channel interference was managed via the antenna configuration and the re-use patte

adjacent-channel interference was managed through the application of a simple frequency plaWith the CDMA channel, all sites reuse the same frequency. Interference isolation is obtained via sh

(inter-sector) and walsh codes (intra-sector).

The ‘valid’ set of offsets is limited to multiples of PILOT_INC (in this example, 2). Offset 4 can interfere w4. If the PILOT_INC is chosen carefully, there should be little concern with 2 interfering w

2 4 6 8 1

Co and Adjacent Offsets

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The setting of PILOT_INC is fundamental to the PN Offset Plan design.What is the impact of changing PILOT_INC?

■ Remaining Set Pilot scanning rate

■ Mis-identification by the Base Station

■ Protects against falsing/interference associated with AdjacentCo-offsets)

Impact of PILOT_INC

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• Remaining Set pilots are assigned a lower priority in th eorder. All actives/candidates are scanned between nei gremaining. And all neighbors are scanned between re mpilots. A remaining set pilot is scanned N times slowe rneighbor (where N is the number of remaining pilots). [facturer specific]

• IS-98 specifies no performance criteria for remaining s e• A remaining set pilot that appears strong enough (and l

enough) to recommend promotion to active needs anal yhaps it should be a neighbor (or have its coverage adj u

• Motorola does not currently honor any requests to ent ehandoff with a remaining set pilot.

Scan Rate for Remaining Set Pilots

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• The BS uses PILOT_INC to translate the pilot phase into a pilot pn offset. If a signal tragreater than PILOT_INC/2 than it may be misidentified by the BS.

• Note the relationship between PILOT_INC and SRCH_WIN_N. It is a rule that SRCHalways smaller PILOT_INC.

• You may want to ask yourself whether it is expected for a MS to interact with a BS at a dthan PILOT_INC/2 away.

• For PILOT_INC = 3, PILOT_INC/2 = 3 x 64 chips / 2 = 96 chips = 23.4 km = 7.8 R (w/R

0 3 6 9 12

PILOT_INC = 3 = spacing between ‘v

0 3 6 9 12

pilot phase reported by MS in PSMM

SRCH_WIN_N

Mis-identification by the Base Statio n

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• An offset must traverse a minimum distance PILOT_IN Cable to fall into the window of the adjacent offset.

• For PILOT_INC = 3 and SRCH_WIN_N = +/- 30 chips, thicorresponds to 3 x 64 - 30 = 162 chips = 39.5 km = 24.5 = 13.2 R (w/R = 3 km).

3 6

PILOT_INC

SRCH_WIN_N = +/- S

Protection Against Adjacent Offset s

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Table: PILOT_INC vs Distance

Pilot_IncDistance

(km)Distance(miles)

1 15.6 9.7

2 31.2 19.4

3 46.8 29.1

4 62.5 38.8

5 78.1 48.5

6 93.7 58.2

7 109.3 67.9

8 124.9 77.6

9 140.5 87.3

10 156.2 97.0

11 171.8 106.7

12 187.4 116.5

13 203.0 126.2

14 218.6 135.9

15 234.2 145.6

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PILOT_INC

LO HI

CO_OFFSET Good Protection ???

ADJACENT OFFSET ??? Good Protection

COMMENTS More OffsetsLarger Reuse Pattern

Larger D/R

Fewer OffsetsSmaller Reuse Patte

Smaller D/R

1 2 4 53 6only for small

marginalco-offset?

marginaladjacentoffset ?

Selecting PILOT_INC

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■ Determine a PILOT_INC which delivers a sufficient interferenagainst adjacent interference.

For a = 24 dB C/I and law = 3.0, m >= 5.31 x (R+s).

■ A smaller PILOT_INC delivers larger number of valid offsetsreuse pattern. As the D/R increases, the likelihood of co-offsediminishes.

■ At this point, it may be possible to adopt any reuse pattern anhigh degree of confidence that we are protected against both adjacent offset interference.

■ Is there anything we can do to optimize the reuse pattern? Aof the reuse distance, D, and PILOT_INC may tell us.

m R s+( ) 10a law 10×( )⁄

1–( )×≥

Approach with small PILOT_INC/large cl

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Table 3-1: Pilot Sequence Offset Index Assignment

R(radius in

km)

R(radius in

chips)s (chips)

a (C/I indB)

law m(chips)PILOT_INC

(offsets)

numberof validoffsets

7 29 10 24 3 207 4 128

5 21 10 24 3 165 3 170

3 12 10 24 3 117 2 256

2.5 10 10 24 3 106 2 256

2 8 10 24 3 96 2 256

PILOT_INC determinations

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•48 cell cluster

•Alpha Sector Offset = 9N -Beta Sector Offset =9NGamma Sector Offset =9N

•There are 26 remaining ocan be organized into 8 separate sites.

35 48 1 14 27

37 2 15 28

34 47 12 13

3 16 29

33 46 11

19 32 45 10

24

26

40

41

42

4330174

38

36

22

21

20

8

7

6

5 18 31 44 9

23

25

39

PN Offset Plan: PILOT_INC = 3

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•73 cell cluster

•Alpha Sector Offset = 6N - 4Beta Sector Offset =6NGamma Sector Offset =6 N

•There are 37 remaining o fcan be organized into sites.

58 66 1 9 17

67 2 10 18

57 65 73 8

3 11 19

56 64 72

47 55 63 71

7

16

25

26

27

2820124

68

59

50

49

48

41

40

39

38 46 54 62 70

6

15

24

31

51

32

14

60

3669

37

42

35

29

61

21135

43

5345

22

52

44

34

23

30

33

PN Offset Plan: PILOT_INC = 2

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•3-Ring, 37 cell cluster

•Alpha Sector Offset = 9N - 6Beta Sector Offset =9NGamma Sector Offset =9N - 3

• There are 57 remaining offsets which can be organizedrate 2-ring cluster of 19 sites.

18 28 1 11 21

29 2 12 22

17 27 37 10

3 13 23

16 26 36

5 15 25 35

9

20

31

32

33

3424144

30

19

8

7

6

54 4

47

53

4

5

A different look at PILOT_INC = 3

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Motorola C

onfidential Proprietary

Table: i & j coordinates for N

-sized Clu

s

Largesti j N D/R PILOT_INC1 0 1 1.73 151 1 3 3.00 152 0 4 3.46 15 <--- 1 rin g2 1 7 4.58 15 <---3 0 9 5.20 152 2 12 6.00 13 <---3 1 13 6.24 124 0 16 6.93 103 2 19 7.55 8 <--- 2 rin g4 1 21 7.94 75 0 25 8.66 63 3 27 9.00 64 2 28 9.17 55 1 31 9.64 56 0 36 10.39 44 3 37 10.54 4 <--- 3 rin g5 2 39 10.82 46 1 43 11.36 34 4 48 12.00 35 3 49 12.12 37 0 49 12.12 36 2 52 12.49 37 1 57 13.08 25 4 61 13.53 2 <--- 4 rin g6 3 63 13.75 28 0 64 13.86 27 2 67 14.18 28 1 73 14.80 25 5 75 15.00 26 4 76 15.10 27 3 79 15.39 28 2 84 15.87 26 5 91 16.52 1 <--- 5 rin g7 4 93 16.70 18 3 97 17.06 1

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• Radius = 3km

•

INC = 619 cells

INC = 348 cells

INC = 337 cells

INC = 273 cells

INC = 1127 cells

Co

D/R 7.55 12 10.54 14.8 19.5 co-offset

C/I (3km) 37.8 29.5 29.5 24.9 17.6 adjacent offset

C/I (6 km) 32.5 24.5 24.5 20.2 13.6 adjacent offset

PILOT_INC - s (chips) 354 162 162 98 34 adjacent offset

PILOT_INC - s (km) 86.4 39.5 39.5 23.9 8.3 adjacent offset

PILOT_INC - s (R) 28.8 13 13 8 2.8 adjacent offset

PILOT_INC (chips) 384 192 192 128 64 compare w/SR

PILOT_INC/2 (chips) 192 96 96 64 32 neighbor proxi

PILOT_INC/2 (km) 46.8 23.4 23.4 15.6 7.8 neighbor proxi

PILOT_INC/2 (R) 15.6 7.8 7.8 5.2 2.6 neighbor proxi

%Overhead Offsets 46 17 51 16 34 insurance

C/I 30 m R s+( )⁄ 1+( )log×=

Comparison of different plans

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Table 3-1: Pilot Sequence Offset Index Assignment

R(radius in

km)

R(radius in

chips)s (chips)

a (C/I indB)

law m(chips)PILOT_INC

(offsets)

numberof validoffsets

7 29 10 16 3 94 2 256

5 21 10 16 3 74 2 256

3 12 10 16 3 54 1 512

2.5 10 10 16 3 49 1 512

2 8 10 16 3 44 1 512

PILOT_INC determinations (w/16 dB C

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■ PILOT_INCSet in the HO_pilot_inc field of the XC SubsystemSET_HO_PARAMS. The range is 1 to 15 (defaults to 1).

■ PILOT_INCSet in the pilotinc field of the DBCM CBSC Command,EDIT CBSC CBSCGEN. The range is 1 to 15 (defaults to 1).

■ PILOT_PNSet for each sector in the pilotpn field of the DBCM Sector ComSECTOR SECGEN. The range is 0 to 511.

■ SRCH_WIN_A, SRCH_WIN_NSet in the srchwina and srchwinn fields of the DBCM Sector CEDIT SECTOR MAHO. The range is 0 to 15 (defaults to 6).

Database Parameters

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■ System TimeAll base station digital transmissions are referenced to a comsystem-wide time scale that uses the Global Positioning Stime scale, which is traceable to and synchronous with Univnated Time (UTC).

■ Time ReferenceThe mobile station shall establish a time reference which is usystem time. This time reference will be the earliest arriving mponent being used for demodulation. This reflects the assummobile station’s fix on system time is always skewed by delawith the shortest active link.

■ PILOT_PNThe Pilot PN sequence offset (index), in units of 64 PN chipfrom 0 to 511. Every transmit sector will have an offset assign

Definitions

of 80


■ Active SetThe pilots associated with the Forward Traffic Channels assigned to tion. It is the base station that assigns all active set pilots to mobile st

■ Candidate SetThe pilots that are not currently in the Active Set but have been rmobile station with sufficient strength to indicate that the associated Channels could be successfully demodulated. As a property of the MHandOff (MAHO), the mobile station promotes a Neighbor Set or pilot to the Candidate Set when certain pilot strength criteria are meommends the pilot to the base station for inclusion in the Active Set.

■ Neighbor SetThe pilots that are not currently in the Active Set or the Candidate Secandidates for handoff. Neighbor Set pilots are identified by the bNeighbor List and Neighbor List Update messages.

■ Remaining SetThe set of all possible pilots in the current system on the current CDassignment, excluding pilots in the other sets. These pilots must be inof PILOT_INC (defined below).

Definitions

of 80


■ SRCH_WIN_N, SRCH_WIN_RThese parameters represent the search window sizes assNeighbor Set and Remaining Set pilots. The mobile stationsearch window for each pilot around the pilot’s PN sequencetiming defined by the mobile station’s time reference.

■ SRCH_WIN_AThis parameter represents the search window size associaActive Set and Candidate Set pilots. The mobile station centewindow for each pilot around the earliest arriving usable multnent of the pilot. Note that in contrast to the neighbor or rsearch windows, the active/candidate search windows are locsignals. That is to say that the center position of the searupdated every scan to track the new location of the earliest apath component.

Definitions

of 80


■ PILOT_ARRIVALThe pilot arrival time is the time of occurrence of the earliest amultipath component of a pilot relative to the mobile stationence.

■ PILOT_PN_PHASEThe mobile station reports pilot strength and phase measeach active and candidate pilot in the Pilot Strength Measusage when recommending a change in the handoff statusassisted handoff). The mobile station computes tPILOT_PN_PHASE as a function of the PILOT_ARRIVPILOT_PN. The pilot arrival component represents the timepilot relative to the time reference or, in other words, how skeis from the mobile’s concept of system time. Note also that thenot identify pilots by their offset index directly, but by their phament. If the pilot arrival was larger than 32 chips (1/2 of a pilomiles), then this could undermine the ability of the base statiotranslate pilot phase into pilot offset index.

Definitions

of 80


■ PILOT_INCThe pilot PN sequence offset index increment is the interval bein increments of 64 chips. Its valid range is from 1 to 15. The muses this parameter in only one manner, to determine which from among the Remaining set. Only valid pilots (i.e. those pmultiples of PILOT_INC) will be scanned. For the moPILOT_INC impacts only the scanning rate applied to Remaaccomplishes this by reducing the number of Remaining pilotsbe scanned. For the base station, its affect is different. In the it is used in properly translating pilot phase back into pilot offsconsequence is that the operator may artificially increase thbetween valid time offsets. By selecting a PILOT_INC of 2, fooperator chooses to limit the number of valid offsets to 256 (508, 510) instead of 512. The increased separation means arrival must be larger before adjacent offset ambiguity is posssequently the likelihood of a strong interferer is reduced.

Definitions


3.15 Neighbor Window Search PlanningFrom Dan DeClerck’s CDG IAT/TR45.4 WG III trip report

BCTel presented the idea that Search window size should be a function of each pilot thatneeded to be scanned, and showed how there would be an improvement mobile pilotscanning speed and thus handoff execution time. They showed examples of where thesetting of the search windows in their system was more than 200 chips.

of 82


of 82


lemen-

3.16 Microcell• Will Bayer’s comments on reverse link timing imbalance between microcells and macrocells (possible imp

tation in motion sim?).

3.16.1 When to Deploy

3.16.2 Intercarrier issues

of 84


of 84


3.17 InterVender Hard Handoff3.17.1 IS-634

of 86


of 86


3.18 InterVender Soft Handoff3.18.1 IS-634

of 88


of 88


3.19 Customer Specific Issues3.19.1 KTF

plots

Mony’s HHO idea

3.19.2 Hong Kong MTR

3.19.3 Singapore

in-building sites with handoff to macrocell

leaky coax coverage

of 90


of 90


3.20 HHO as soon as One-WayAfter an inter-CBSC SHO, perform the HHO as soon as the call goes into one-way on thetarget CBSC. Otherwise, wait for DAHO.

of 92


of 92


g ancu-d softlures.opti-

rithmoft

3.21 CDMA Soft Handoff Optimization

3.21.1 Introduction

The soft handoff optimization is a continuous process that is required in maintaininacceptable1 system performance level in terms of call quality. This section of the doment focuses on the detailed approaches in recognizing the root cause of failehandoffs as well as approaches in correcting the various types of common faiThese common failures are typically encountered during the CDMA initial system mization phase or during system expansion (installing additional BTS).

Resolving the failed soft handoffs that result in an “RF Loss”2 is usually the main em-phasis in the optimization process. Provided that the software of the handoff algois executed according to design3, there are basically two general categories that s

1. 1% to 2% system RF Loss rate.2. An event where either the Reverse or Forward Traffic Channel is lost.

ings. ana-

d sys- soft

g.

handoff failures fall into: 1) RF coverage hole, and 2) non-optimal parameter settThis document will discuss approaches in recognizing the two types of failures bylyzing mobile station logs and base station logs.

This document also contains brief overviews of soft handoff related parameters antem algorithms. This will provide a general understanding of the mechanics ofhandoffs.

3.21.2 General Mechanics of Soft Handoff

3.21.2.1 Overview of Soft Handoff Parameters

Recommended settings for adjustable system parameters:

■ TADD = 24 ~ 28 (-12dB ~ -14dB)

■ TDROP = 26 ~ 32 (-13dB ~ -16dB)

■ TTDROP = 1 ~ 4 (1 sec ~ 6 sec)

■ TCOMP = 0 ~ 4 (0 ~ 4dB)

■ SrchWinA = 6 (28 PN chips)

■ SrchWinN = 8 (60 PN chips)

■ SrchWinR = 9 (80 PN chips)

3. There are instances where extra effort is required when encountering a possible infrastructure software buAn MR (Modification Request) is generated once the issue has been identified.

CDMA Soft Handoff OptimizationMotorola Confidential Proprietary


recom-l fash-

e pi-

radius

ag”obilecurs.ile sta-

the

offe-

ectors

ech-

ntolue

There are, however, exceptions where the parameters may be set outside the mended range. Examples of situations where parameters are set in an atypicaion are described below:

✥Tadd and Tdrop parameters could be adjusted relatively high in regions wherlots become difficult to manage (no dominant pilot)

✥The mobile station Window Search Sizes could be increased when the site is extremely large (8 to 15 miles)

✥Tcomp parameter could be set large to suppress Fast Pilot Shuffling1

✥TTdrop parameter could be set larger to “slow down” soft handoff activity

3.21.2.2 Soft Handoff Detection

All soft handoff decisions are based on the Ec/Io information and the “keep-flstatus from the PSMM (Pilot Strength Measurement Message) sent by the mstation. The PSMMs are triggered when a Tadd, Tcomp, or a Tdrop event ocThe soft handoff parameters are set on a sector basis, and are sent to the mobtion by theSystem Parameter Message on the Paging Channel or by theExtendedHandoff Direction Message on the Forward Traffic Channel.

The System Parameter Message is sent at least once every 1.28 seconds over Paging Channel. TheExtended Handoff Direction Message is sent each time ahandoff criteria is met. If there are more than one sector in theExtended HandoffDirection Message(i.e. calls that are instructed to transition into a soft handstate), the MM will use the following criteria in selecting the soft handoff paramters in those instances when the values are different for each of the involved s(refer to illustration 11.2.0.2-a):

1) The value of TDrop shall be the largest value from each of the sectorsinvolved 5

2) The value of TAdd TComp and TTDrop shall be the smallest value from eachof the sectors 2

3) The value of SrchWinA, SrchWinR, SrchWinN shall be the largest value fromeach of the sectors involved

1. Fast Pilot Shuffle is a soft handoff algorithm triggered at the MM when it detects three pilots in the activsetand a candidate pilot that measures a stronger Ec/Io than at least one of the pilot in the active. The meanism of this algorithm will be discussed later in the document.2. Referring to Tdrop and Tadd: “These parameters, which actually represent fractions, are transformed itheir current values via a log function. Therefore, the largest actual value is represented by the smallest vaof the parameter,and vice-versa.”, HOPC SFS,ver6.0, HO_Exec_Preface, page 50.

Page of 106


activee the

ector.ilot isold.

softDR,es areain-

fromr-

ore,e set.ilots

as-hen

mea-M)

con-r the

For CBSC software release R7.x and earlier, a candidate pilot is added to the set via soft handoff execution when the Ec/Io reading from the PSMM is abovTadd threshold1 and when there are less than 3 active pilots in the active set2. Ideal-ly, the Tadd parameter should be above the Tdrop parameter for any given sThe idea is to allow a hysteresis between the two thresholds so that once a padded into the active set, it does not immediately fall below the Tdrop threshThe hysteresis will prevent the mobile station from attempting unnecessaryhandoffs. This not only reduces the CPU utilization time at the MM and the XCbut will decrease the Traffic Channel message rate. If Traffic Channel messagreduced, it is less likely that a Dim-and-Burst frame will be sent over the air (mtain good speech quality).

In adding a pilot to the active set, the focus is to prevent the mobile station dropping a call caused bynot having the correct set of pilots in the active set. Curently, the infrastructure is limited to having 3 pilots in the active set, therefthere will be instances where a fourth pilot is strong enough to be in the activExtra effort is required in adjusting the soft handoff parameters such that the pare “shuffled” in and out of the active set smoothly. This “shuffling” process issisted by an algorithm called the Fast Pilot Shuffle that is triggered at the MM wit detects the scenario mentioned above.

The concept of Fast Pilot Shuffle is to detect a pilot in the candidate set that issured to be relatively stronger (via the measurement of pilot Ec/Io in the PSMthan any of the three pilots in the active set, regardless of the “keep-flag” statustained in the PSMM. The weakest pilot in the active set is dropped, and afte

1. The infrastructure has the capability of executing soft handoffs in either the Tcomp mode or the Taddmode. The recommended mode is Tadd.2. There will be significant soft handoff algorithm changes in R8.1 (N-way complex handoff). This featurewill support up to 6 pilots in the active set.

Sector-a Sector-b

Figure 11.2.0.2-a

Tadd

Tdrop

Tcomp

TTdrop

SrchWinA

- 14dB

- 15dB

3 dB

4 sec

7 chips

- 12dB

- 16dB

1 dB

2 sec

6 chips

Extended Handoff Direction Message

- 14dB

- 15dB

1 dB

2 sec

7 chips

Assume that the Extended Handoff Direction Message includes 2 sectors, sector aand sector b. The MM data base parameters are listed above according to each ofthe sectors. The values listed under “Extended Handoff Direction Message” are thevalues selected by the MM. This list will be included in the Extended HDM Messagewhich is sent down to the mobile station on the Forward Traffic Channel.

Page of 106


pilot

di-

SC

ters is

drop

of 4 of 1ly ath ahan Ec/Iodropbet-seen havee theeak,fade

mobileighborearchindow,exces-accu-e the

success of the soft handoff drop, a soft handoff is triggered to add the candidatethat is the strongest as recorded in the subsequent PSMM.

The following is the Fast Pilot Shuffle detection criteria1:

1) The candidate Ec/Io is a TComp event.2) The candidate’s Ec/Io is greater than at least two of the active pilot’s Ec/Io

3) The candidate Ec/Io is equal to or greater than the TAdd threshold, and the candate’s Ec/Io is greater than at least two of the active pilot’s Ec/Io

Note: The third Fast Pilot Shuffle detection criterion will be applied in future CBsoftware releases starting from software release R8.x.

In many cases, driving the same route several times while adjusting the paramenecessary in order to perfect difficult locations.Caution must be taken when adjust-ing the RF power or the soft handoff parameters, as it may improve the RF condi-tion for the intended location, but possibly degrade other locations.

A pilot is dropped from the active set when an Ec/Io from the PSMM is below the Tthreshold for a TTdrop period. Theweight or thesignificance of information containedin the PSMM is controlled by how the parameters are set.

For example, the weight of a PSMM triggered by a Tdrop of -15db and a TTdropsec is more significant than a PSMM triggered by a Tdrop of -15db and a TTdropsec. Naturally, if a pilot that is continuously below the Tdrop threshold for relativelong period (period controlled by TTdrop), the infrastructure may drop the pilot wirelatively high level of confidence. In other words, the infrastructure will, more tlikely, never encounter a case where there is a sudden improvement of the pilotmeasurement, via the PSMM, after deciding to drop from the active set. If the TTtimer is relatively short, there is a high risk that the pilot Ec/Io will change (for the ter) by the time the infrastructure makes it’s decision to drop. This is commonly when the system makes the decision to drop a reasonably strong pilot that maybriefly been in a fade or may have been receiving a weak multi-path ray at the timPSMM was reported. It would appear that, from the PSMM, the pilot was very wtherefore, the system will drop the pilot not knowing that it would recover from the or the weak multi-path.

The mobile station window search size parameters should be set such that the station searcher is capable of searching all multi-paths in the active set, and all nepilots without degrading the accuracy of locating a valid ray. The speed of the smechanism is dependent upon the search window size. The wider the search wthe longer the mobile station takes to complete it’s search across the window. The sive window search size may cause “under-sampling” of the signal such that an inrate measurement is made; therefore, optimization may be required to determinmost effective window search size value.

1. HOPC SFS, Handoff Detection, Ver 6.0

Page of 106


er- rela-

tione pi-fer-ingwithsizeon tohbord the

rfor-

ng forhbor

mptrtu- thealyzeor, allcreas-

cher

The following is an illustration (Figure 11.2.0.2-b) that may provide a visual undstanding of how the window search parameter is associated with the distancetive to the surrounding BTS.

IS-95A (in reference to the Neighbor search window size): “The mobile stashould center the search window for each pilot in the Neighbor Set around thlot’s PN sequence offset using timing defined by the mobile station’s time reence”. The mobile station’s time reference is typically the earliest arrivcomponent being used for demodulation. The above figure illustrates that PN_A, from BTS#1, as the earliest arriving ray, the Neighbor search window must be at least set to 26.4 chips (+/- 13.2 chips) in order for the mobile statidetect PN_B, BTS#2, which is 6 miles away from the mobile station. The neigsearch mechanism applies for when the mobile station is in the Idle State anTraffic State.

3.21.2.3 Neighbor List ConfigurationMaintaining the correct set of neighbor list for each sector is crucial in the pemance of soft handoff. As stated in the HOPC SFS1, “The mobile station uses theneighbor set as a way of reducing the amount of resources applied to searchihandoff candidates. For this reason it is important that the mobile station’s neigset is appropriate for its location within the system.”

With the current architecture of the infrastructure system, a soft handoff attewill be rejected if the pilot to be added is not listed in the neighbor list. Unfonately, an effective way in determining an accurate set of neighbor list duringinitial stages of system deployment is to drive test the handoff regions and anwhich neighbor pilots are most likely to be used as active pilots. For each sectneighbors must be sorted and listed in the system database in the order of de

1. HOPC SFS. “HO_Exec_Preface”, ver 6.0, page 49

BTS # 1 PN_A BTS #2 PN_B

Earliest arriving ray(reference Pilot_A)

4 mile radius

6 miles away from mobile station

In order for the mobile station searto be able to detect the ray fromBTS#2, the Neighbor windowsearch size must be at least26.4 chips (+/- 13.2chips) since

2 miles (approx. 13.2 chips)

4 miles away from mobile station

the ray from BTS#2 has a delayof 13.2 chips relative to theearliest arriving ray (BTS#1).

Figure 11.2.0.2-b

Page of 106


eenlist.

uld be the)ringwn.

pilot-

sam-ivene-

.

-

ing priority . Developing such a list is a time consuming task. There have bmany suggestions on different approaches in developing an optimal neighbor 1

One example is to have the general user generate data so that the CDL logs comanipulated.2 In each CDL record, there is a field that lists all the sectors fromlast Handoff Recognize Message received by the MM (LAST_MAHO_ACT3.With enough samples, the frequency of a given pilot, a reference pilot “A”, paiup with the rest of the pilots found in each of the CDL logs can be broken doThis data can then be used to find the weight of each neighbor pilot relative to“A”, thus, developing a prioritized neighbor list for pilot “A”. This approach, however, is only valid for a system that is running at a significant load since large ples of CDL logs are required in calculating an accurate probability that a gpilot “A” would be paired with another pilot “x”. Please refer to the illustration blow (Figure 11.2.0.2-c):

1. Ideally, an initial neighbor list (prioritized) is derived prior to system deployment by means of simulator2. Call Detail Log generated at the OMCR.3. Last MAHO Information Active Pilot. PN Index Offsets from the Handoff Recognized message are converted to a BTS (LAST_MAHO_ACT_BTS) and Sector(LAST_MAHO_ACT_SECTOR) . STR(LAST_MAHO_ACT_STR) is the Ec/Io Measurement as received from the Mobile Station, displayed inhex.

CDL #1: Pilot_A, Pilot_B, Pilot_CCDL #2: Pilot_A, Pilot_CCDL #3: Pilot_A, Pilot_DCDL #4: Pilot_A, Pilot_B, Pilot_DCDL #5: Pilot_A, Pilot_C, Pilot_DCDL #6: Pilot_A, Pilot_D, Pilot_ECDL #7: Pilot_A, Pilot_BCDL #8: Pilot_A, Pilot_B, Pilot_CCDL #9: Pilot_A, Pilot_BCDL #10: Pilot_A, Pilot_E

Extract Last_RF_Conn_Sector field listed in CDL (CDL Samples):

Figure 11.2.0.2-c

Page of 106


date

ter).

eigh-inge casege”ts as-eigh-bor

se:

The neighbor list at the mobile station will be updated (via the Neighbor List UpMessage on the TCH) provided that one of the following condition is met:

✥Always send a Neighbor List Update on a handoff add situation (either soft or sof

✥Send a Neighbor List Update on a handoff drop situation only if the last time thelist was sent to the mobile station had to be truncated (i.e. was > N8m, or 20, neigh-bors)1.

The maximum amount of pilots in a neighbor list created by the base station is 20 nbor pilots2. The MM will enter the neighbor pilots into the list in the order of decreaspriority, as determined by the order of the neighbors in the system database. In thof the mobile station having more than one pilot in the active set, the MM will “merthe database entries in a round robin order. When the total amount of neighbor pilosociated with each of the pilots in the active set exceeds 20, the lowest priority nbors will be truncated off the list. Please refer to the following Soft Handoff NeighList “Merge” Example3 (Figure 11.2.0.2-e).

1. Refer to HOPC SFS for more information on the criteria in sending the Neighbor List Update Message.2. (IS-95A: N8m = 20)3. Barry J.Menich’s Internal Memo, MM Management of Neighbor Lists and Remaining Set Handoff (CDMA),October 18, 1995.

From the above set of CDL samples the following numbers may be generated:

Pilot_A paired with Pilot_B = 5 counts (CDL#1, CDL#4, CDL#7, CDL#8, CDL#9)Pilot_A paired with Pilot_C = 4 counts (CDL#1, CDL#2, CDL#5, CDL#8)Pilot_A paired with Pilot_D = 4 counts (CDL#3, CDL#4, CDL#5, CDL#6)Pilot_A paired with Pilot_E = 2 counts (CDL#6, CDL#10)

Neighbor list for Pilot_A in the order of decreasing priority as entered in the databa

1)Pilot_B2)Pilot_C3)Pilot_D4)Pilot_E Figure 11.2.0.2-d

Page of 106


ll al-from

ach in and

then,ro-Therek sta-com-

er, itst the

and

The NGHBR_MAX_AGE parameter is recommended to be set to 0, as the list wiways contain the most updated neighbors. This will prevent the mobile station leaving “aged” pilots in the neighbor list; thus, forcing a direct replacement.

3.21.3 Mobile Station/Base Station Data AnalysisThere are many approaches in analyzing “RF Loss” cases. One common approcharacterizing an “RF Loss” is to analyze the logs from the Qualcomm Mobile DMthe base station CBSC SMAP. The useful mobile station information extracted fromoutput of QC NPAR1 tool are: over-the-air IS-95A messages, FWD FER informatioTX/RX/RSSI levels, and FWD/REV frame rate and type. The useful information pvided by the CBSC SMAP are the call processing messages at the XCDR CPP. are several non-commercial scripts that are located on the OMCR or the local wortion at the MTSO that will extract the call processing messages for SMAP. The monly used decoding scripts are called “re” and “dmta”2. Other information from theraw SMAP logs are available (i.e. rev FER, target Eb/No, FWD TCH gain), howevis not necessary to characterize all of the “RF Loss” calls in such great detail, as jumessaging is sufficient in most cases.

The “RF Loss” calls are typically broken down to the following broad categories:

- poor forward link due to weak RSSI

- poor forward link due to weak Ec/Io in good RSSI (non-dominant pilot)3

1. Qualcomm NPAR decoding tool2. usage: re <smap raw file> | dmta (script developed by Mike Lynch)

A1

Highest

A2A3A4A5A6A7A8

B1B2B3B4B5B6B7B8

C1C2C3C4C5C6C7C8

A1B1C1A2B2C2A3C3A4B4A5B5C5A6B6C6A7B7C7A8

Cell A

(Oldest)

Neighbor List

Cell B

Neighbor List

Cell C

(Youngest)N

eighbor List

Merge Assume:A1 = B3A2 = C4

Ordered list sent tomobile inNeighborList Update Message

Note: B8 and C8 arenot included in the list

Soft Handoff Neighbor List “Mer ge” Example

Prob.

LowestProb.

1)Merge neighbor lists in round-robin fashion starting with the oldest cell in the active setproceeding to the youngest cell.2)Eliminate all duplicates from the merged list.3)Truncate the list to 20 entries

B3 and C4 are notincluded in themerged list as theyare duplicates.

as they are truncated.

Figure 11.2.0.2-e

Page of 106


)

al re-

softn willdja-

ystem.

theI) istionarac-

guresafeSSIully with

ended“non-

stment

mi-omi-gorye ac-ted in

at theThisegionfullypropri-tation

/Io

- poor reverse link due to interference

The following are common characteristics for when a general “RF Loss” occurs:

■ RSSI level very low (weaker than -95dBm)

■ Ec/Io level very low (weaker than -13dB)

■ Neighbor pilots remain at a poor level (weaker than -13dB )

■ Forward erased frames detected (several Power Measurement Report Message

■ Missed base station layer 2 acknowledgment message (logs will indicate severpeated messages

Although category #1, poor forward link due to weak RSSI, is not associated withhandoff failures, it is important to recognize that, in some cases, the mobile statiofind itself in an area where the soft handoff regions are not fully overlapped with acent sectors. This scenario may appear that the mobile station is at an edge of a s

Figure 1-a is the Sparse AGC Power Control Information Message extracted fromQC Mobile DM. This simply illustrates that the mobile station receive power (RSSvery low indicating that either the output of the “RF_Pilot_PWR” at the base stamay be too low or the line of sight of the base station may be blocked. This RF chteristic will also contribute to very poor pilot Ec/Io measurements as illustrated in fi1-b. If an “RF Loss” occurs with data that is similar to figure 1-a and figure 1-b, it is to conclude that the “drop call” was caused by poor forward link due to weak R(“RF Loss” category #1). A common method in correcting this problem is to carefincrease the pilot power so that it forms a sufficient coverage area with an overlapthe adjacent sectors such that it forms a stable soft handoff region. It is recommthat the power is not transmitted too high to the point where it creates unwanted dominant pilot” regions in different unexpected locations.Caution must be takenwhen adjusting the RF power or the soft handoff parameters, as it may improvethe RF condition for the intended location, but possibly degrade other locations.Depending on the root cause of the problem, other methods may require a re-adjuof the antenna direction or possibly adding a BTS at the most optimal location.

“RF Loss” category #2, poor forward link due to weak Ec/Io in good RSSI (non-donant pilot), is a condition where the forward link is deteriorated, as there are no dnant pilot in the vicinity. The RSSI, however, is at an acceptable level, unlike in cate#1. For the mobile station log in figure 1-b, it is apparent that the Ec/Io for both thtive set and the candidate set is measured to be very weak. In addition, as illustrafigure 1-c, the RSSI level is measured to be at an acceptable level indicating thpoor pilot Ec/Io is not caused by the lack of base station “RF_Pilot_PWR” power. condition creates problems in soft handoffs as the mobile station finds itself in a rthat is commonly referred to as a “non-dominant pilot” region. The idea is to careset the Tadd and Tdrop threshold such that the PSMMs are triggered at just the apate time. For this particular non-dominant pilot case, the RSSI level at the mobile s

3. Non-dominant pilot is a term often used to describe a an RF condition where all of the surrounding Pilot Ecmeasures to be weak. The RSSI, however, is measured to be a an acceptable level.

Page of 106


ed at

ndoff station ends;ment opti-mo-hat anwith-mobile mo-f poor

g the

d

is at an acceptable level (stronger than -90dBm) but all pilots in the vicinity measurthe mobile station are poor ( pilot Ec/Io weaker than -13dB).1 The neighbor pilots actsas interference to the point where a dominant pilot no longer exists. The soft haprocedures then becomes staggered as frame erasure rate between the mobileand the base station increases. There will be many message re-tries from boththus, an increased likelihood of a timer expiring (fade timer/message acknowledgtimer). To alleviate this sort of behavior, the soft handoff parameters must be setmally in order to maintain the optimal pilot combination in the active set while the bile station passes through such harsh Ec/Io environment. Figure 1-d indicates tExtended Handoff Direction Message is sent multiple times from the base station out an acknowledgment, which indicates that the message is not received at the station. Combining figure 1-b, figure 1-c along with figure1-d, it is suggests that thebile station was in an area where the forward link has deteriorated with the cause oforward link due to weak pilot Ec/Io in a region with strong RSSI.Again, the key is toset the parameters such that the mobile station doesnot attempt unnecessary softhandoffs. This will decrease the risk of messages being missed; thus, decreasinchance of timing out either at the mobile station or the base station.

1. There is no scientific reasoning in determining what is “weak” and what is “strong”. The numbers mentioneare strictly associated with the illustrated case.

Page of 106


08/04/1997 02:39:00.492 [18] Sparse AGC Power Control Information

adc_therm = 0x009c

batt_volt = 0x008d

tx_pwr_limit = 0x00e0

Rx AGC Average = 0xffa0, Rx Power = -95.331 dBm

ADJ Average = 0x0002, ADJ = -1.430 dB

TX AGC Average = 0x00da, AGC Power = 20.703 dBm

TX Turnaround Power = 20.901 dBm

0: Rx/Tx/Adj = -95.915, 17.083, -4.000

1: Rx/Tx/Adj = -93.581, 22.083, 0.000

2: Rx/Tx/Adj = -95.915, 15.750, -6.000

3: Rx/Tx/Adj = -96.915, 19.750, -2.000

4: Rx/Tx/Adj = -96.248, 22.417, 1.000

5: Rx/Tx/Adj = -97.248, 20.417, -2.000

6: Rx/Tx/Adj = -96.581, 21.083, -2.000

7: Rx/Tx/Adj = -94.248, 18.750, -4.000

8: Rx/Tx/Adj = -95.248, 18.083, -4.000

9: Rx/Tx/Adj = -94.915, 18.083, -4.000

10: Rx/Tx/Adj = -97.248, 17.750, -4.000

11: Rx/Tx/Adj = -94.581, 19.750, -2.000

12: Rx/Tx/Adj = -91.248, 22.083, 1.000

13: Rx/Tx/Adj = -96.248, 17.417, -4.000

14: Rx/Tx/Adj = -97.915, 20.750, -2.000

15: Rx/Tx/Adj = -92.915, 20.417, -2.000

16: Rx/Tx/Adj = -96.581, 20.417, -2.000

17: Rx/Tx/Adj = -94.581, 20.417, -2.000

18: Rx/Tx/Adj = -94.915, 22.083, 0.000

19: Rx/Tx/Adj = -96.915, 22.750, 0.000

20: Rx/Tx/Adj = -96.915, 19.083, -4.000

80: Rx/Tx/Adj = -96.248, 21.750, -1.000

81: Rx/Tx/Adj = -96.915, 19.750, -3.000

82: Rx/Tx/Adj = -94.248, 21.417, -1.000

83: Rx/Tx/Adj = -96.581, 21.750, -1.000

84: Rx/Tx/Adj = -95.248, 22.417, 0.000

85: Rx/Tx/Adj = -96.248, 20.417, -2.000

86: Rx/Tx/Adj = -95.581, 18.750, -4.000

87: Rx/Tx/Adj = -95.915, 20.750, -2.000

88: Rx/Tx/Adj = -94.915, 18.417, -4.000

89: Rx/Tx/Adj = -95.248, 20.417, -2.000

90: Rx/Tx/Adj = -94.915, 22.417, 0.000

91: Rx/Tx/Adj = -94.248, 18.750, -3.000

92: Rx/Tx/Adj = -96.581, 21.083, -1.000

93: Rx/Tx/Adj = -96.915, 21.417, -1.000

94: Rx/Tx/Adj = -95.581, 22.083, -1.000

95: Rx/Tx/Adj = -95.915, 21.417, -1.000

96: Rx/Tx/Adj = -95.915, 22.750, 1.000

97: Rx/Tx/Adj = -94.581, 22.750, 1.000

98: Rx/Tx/Adj = -92.581, 22.750, 1.000

99: Rx/Tx/Adj = -94.915, 21.083, -1.000

Note: very low RSSI level indicating that

the “RF_Pilot_PWR” at the base station

may be too low

Figure 1-a

Page of 106


ationhighse it’s TXhenasion-t in a

verse thatefault

nariowithinana-re no

2 .

Category #3 is an “RF Loss” caused by poor reverse link. Typically, the base stwill detect a Layer 2 failure or detect a fade time-out. When encountering very FER on the reverse link, the base station instructs the mobile station to increapower. This power control behavior is easily recognized as the mobile stationgain adjust is very large, as indicated in figure 1-c. The scenario will occur wthe power control parameters are not set according to the default settings. Occally, after loading a new software release, the parameters are accidentally seway that the mobile station transmits unusually high power. This creates a relink noise rise that disrupts the reverse link for the surrounding mobile stationsare in use. It is critical that all power control related parameters are set to the dvalues.

Another source of reverse link degradation is in-band interference. This scehas been encountered close to local airports where signals are transmitted the CDMA band. Similarly, in-band signals may also be generated from other log infrastructure systems that are deployed near by. Unfortunately, there atechnical approach in correcting the above two situations.

08/04/1997 02:38:13.732 [0F] REVERSE TC CAI


ack_seq 1, msg_seq 5, ack_req 1, encryption 0

ref_pn 0x13a = 314 ( 314 )

pilot_strength 25 ( -14.5 dB )

keep

pilot_pn_phase[0] 0x76 = 118 ( 118 )

pilot_strength[0] 28 ( -14.0 dB )

keep

pilot_pn_phase[1] 0x1b81 => 110 + 1 chip ( 110 )


drop

08/04/1997 02:38:13.772 [10] REVERSE TC CAI



ref_pn 0x13a = 314 ( 314 )

pilot_strength 25 ( -14.5 dB )

keep

pilot_pn_phase[0] 0x1d82 => 118 + 2 chips ( 118 )


keep

pilot_pn_phase[1] 0x1b83 => 110 + 3 chips ( 110 )


drop

pilot_pn_phase[2] 0x2686 => 154 + 6 chips ( 154 )


keep

08/04/1997 02:38:13.872 [11] REVERSE TC CAI

Power Measurement Report Message


Errors_detected 3

pwr_meas_frames 8

last_hdm_seq 2

pilot_strength 30

pilot_strength 33

pilot_strength 26

The Pilot Strength Measurement Messages indicate

very poor Ec/Io measurements for all listed pilots

(-13.5dB ~ -18.0dB). The Power Measurement Report Message

indicate very high fwd FER (3 frame erasures out of 8),

along with weak pilot Ec/Io measurements in the active

set (pilot_strength = -15dB,-16.5dB,-13dB).

With the RSSI information from figure 1-a, it is safe

to assume that this particular region is considered to

be lacking in power. The RF pilot power for the base

Station(s) that are designated to serve this particular

region should be adjusted to eliminate the RF hole.

Figure 1-b

08/04/1997 02:38:11.872 [11] Markov

8Kpr 3 D1/2 0 D1/4 0 D1/8 9 SIGs 04800 2 2400 0 1200 0 FERR 0 ERAs 86

Note:the Markov information also indicate 86 erased framesout of 100 detected from 02:38:11.872 to 02:38:13.87

Page of 106


t Softrob-

3.21.4 General Conclusion

This document provides sufficient background on the mechanics of the currenHandoff algorithm, along with recommended methods in resolving common p

08/04/1997 02:38:28.632 [09] Sparse AGC Power Control Information adc_therm = 0x009c batt_volt = 0x0092 tx_pwr_limit = 0x00de Rx AGC Average = 0xffc0, Rx Power = -84.611 dBm ADJ Average = 0xfffa, ADJ = 3.450 dB TX AGC Average = 0x00c9, AGC Power = 14.840 dBm TX Turnaround Power = 15.061 dBm 0: Rx/Tx/Adj = -87.248, 12.750, 0.000 1: Rx/Tx/Adj = -84.915, 14.750, 2.000 2: Rx/Tx/Adj = -86.581, 17.083, 4.000 3: Rx/Tx/Adj = -85.581, 16.417, 3.000 4: Rx/Tx/Adj = -86.915, 21.750, 9.000 5: Rx/Tx/Adj = -86.248, 21.750, 9.000 6: Rx/Tx/Adj = -86.915, 21.083, 8.000 7: Rx/Tx/Adj = -86.248, 18.750, 6.000 8: Rx/Tx/Adj = -86.915, 16.417, 4.000 9: Rx/Tx/Adj = -86.248, 14.750, 2.000 10: Rx/Tx/Adj = -84.581, 14.417, 2.000 11: Rx/Tx/Adj = -85.915, 11.417, 0.000 12: Rx/Tx/Adj = -85.248, 13.083, 1.000 13: Rx/Tx/Adj = -84.248, 14.083, 2.000 14: Rx/Tx/Adj = -85.581, 16.750, 5.000 15: Rx/Tx/Adj = -85.248, 15.417, 4.000 16: Rx/Tx/Adj = -84.915, 15.417, 4.000 17: Rx/Tx/Adj = -85.915, 14.083, 2.000 18: Rx/Tx/Adj = -85.915, 13.083, 0.000 19: Rx/Tx/Adj = -85.248, 9.083, -3.000 20: Rx/Tx/Adj = -82.581, 13.750, 3.000

80: Rx/Tx/Adj = -88.248, 16.417, 4.000 81: Rx/Tx/Adj = -84.248, 17.083, 4.000 82: Rx/Tx/Adj = -84.248, 14.083, 2.000 83: Rx/Tx/Adj = -84.915, 15.750, 4.000 84: Rx/Tx/Adj = -87.248, 14.083, 2.000 85: Rx/Tx/Adj = -85.581, 15.083, 2.000 86: Rx/Tx/Adj = -86.581, 14.750, 2.000 87: Rx/Tx/Adj = -84.581, 16.083, 4.000 88: Rx/Tx/Adj = -86.581, 15.083, 2.000 89: Rx/Tx/Adj = -84.915, 14.417, 2.000 90: Rx/Tx/Adj = -86.581, 12.750, 0.000 91: Rx/Tx/Adj = -84.915, 15.083, 2.000 92: Rx/Tx/Adj = -84.581, 12.417, 0.000 93: Rx/Tx/Adj = -84.915, 12.417, 0.000 94: Rx/Tx/Adj = -83.581, 14.083, 2.000 95: Rx/Tx/Adj = -82.581, 13.417, 2.000 96: Rx/Tx/Adj = -83.915, 15.083, 4.000 97: Rx/Tx/Adj = -84.248, 16.750, 6.000 98: Rx/Tx/Adj = -85.915, 17.417, 6.000 99: Rx/Tx/Adj = -84.915, 17.750, 6.000

Note:High transmit gain adjust whilemaintaining a good RSSI level. Thisis a clear indication that the basestation is receiving erased frames.

Figure 1-c

10207 9f032b94 01 --- Ext Handoff Direction -----> 0 2 1 Tue Mar 18 1997 14:21:24:580 10210 9f032b94 01 --- Ext Handoff Direction -----> 2 2 1 Tue Mar 18 1997 14:21:24:640

10213 9f032b94 01 --- Ext Handoff Direction -----> 2 2 1 Tue Mar 18 1997 14:21:25:020 10216 9f032b94 01 --- Ext Handoff Direction -----> 2 2 1 Tue Mar 18 1997 14:21:25:400 10219 9f032b94 01 --- Ext Handoff Direction -----> 2 2 1 Tue Mar 18 1997 14:21:25:780 10225 9f032b94 DM_SOFT_ADD_FAILURE CIC= 1c12 Call Id= 1e5bCell Id= 0074 10228 9f032b94 01 --- Ext Handoff Direction -----> 2 3 1 Tue Mar 18 1997 14:21:26:080 10231 9f032b94 DM_SOFT_ADD_START CIC= 1c12 Call Id= 1e5bCell Id= 002c 9f032b94 R_NORMAL Tue Mar 18 1997 14:19:36:320 10234 9f032b94 01 --- Ext Handoff Direction -----> 2 2 1 Tue Mar 18 1997 14:21:26:460 10237 9f032b94 01 --- Ext Handoff Direction -----> 2 4 1 Tue Mar 18 1997 14:21:26:540 10240 9f032b94 01 --- Ext Handoff Direction -----> 2 2 1 Tue Mar 18 1997 14:21:26:920 10243 9f032b94 01 --- Ext Handoff Direction -----> 2 2 1 Tue Mar 18 1997 14:21:27:300 10246 9f032b94 01 --- Ext Handoff Direction -----> 2 2 1 Tue Mar 18 1997 14:21:27:680 10249 9f032b94 01 --- Ext Handoff Direction -----> 2 2 1 Tue Mar 18 1997 14:21:28:060 10252 9f032b94 01 --- Ext Handoff Direction -----> 2 2 1 Tue Mar 18 1997 14:21:28:440 10258 9f032b94 01 --- Ext Handoff Direction -----> 2 2 1 Tue Mar 18 1997 14:21:28:820 10261 9f032b94 01 --- Ext Handoff Direction -----> 2 2 1 Tue Mar 18 1997 14:21:29:200 10264 9f032b94 01 --- Ext Handoff Direction -----> 2 2 1 Tue Mar 18 1997 14:21:29:580 10267 9f032b94 DM_RELEASE_START CIC= 1c12 Call Id= 1e5bCell Id= 002c 9f032b94 R_RF_LOSS Tue Mar 18 1997 14:19:40:160

Figure 1-dCBSC SMAP Message Output

Page of 106


nsionmustnt.

l ways

to re-t. Al- the

the ares mayatas itss, the most

thee in-

ed to exe-m onerrect-

sys-

lems encountered in the system deployment phase or in the system expaphase. It is suggested that to be effective in optimizing a CDMA system, one be familiar with the Soft Handoff algorithms and logs mentioned in this docume

The methods recommended throughout this document are just one of severain correcting common problems. It is, however, the moststrongly recommendedmethods. Other methods in correcting common field problems are attempting create the scenario in the test laboratory where it is in a controlled environmenso, using a variety of mobile station manufacturers in field testing to eliminatepossibility of a defected mobile station. Referring to the simulation result forsystem that is being optimized may provide additional RF information. Therealso other debugging sources throughout the subsystems where detailed logbe captured (e.g. callproc1.out at the MM, XCDR CPP via MMI port, MCC dvia MMI port), however, most of which are strictly used in laboratory testing aimpacts system performance when used on a commercial system. Nonethelerecommendations described throughout this document is recognized to be theeffective way in correcting common problems under the given circumstances1.

Currently, there is research effort in developing an algorithm which will allow optimization process to be automated. When this algorithm is integrated into thfrastructure system in the future software release, this document will be modififocus on automation. Unfortunately, the current optimization process must becuted manually, in that one must drive test a system and analyze each probleby one. It is a time consuming task, however, it is the most accurate way in coing a problem.

1. Recommendations are based on the fact that the system is being optimized while stem deployment ortem expansion.

Page of 106


g” and

Traffic planning for HHO:• DAHO

• Idle-mode and TCH.

• Where to place carrier boundaries as a function of traffic density or gradient? Reference my email on “tierinJohn Voigt’s PowerPoint slide (probably not right).

PN planning for microcells and in-building sites contained within macrocell coverage.• Reference Sam Fernandez email.

Inter-CBSC SHO• Performance

• How to optimize

• Any consideration for inter-vendor?

KTF handoff between Motorola and Samsung• Mony’s HHO idea feasability?

• Still need to look at plots after technique has been identified.

DAHO description and optimization strategies.• Notes on Ec/Io statistics fromPilot Strength Measurement Message.

Pilot Beacons description and optimization strategies.• Hong Kong input.

• Notes from Barry’s slides.

Future Possibilities and implications of spec changes, etc.• Edge Sensing (note that edge sensing can be used to make DAHO more robust).

• TIA improvements a la Qualcomm/DeClerck method.

Time-line and future “vision” for HHO.

Ft. Worth tests on frequency-hopping pilot beacons.

Deployment “Special Situations”• Hong Kong MTR deployment and optimization

• Singapore in-building sites with handoff to macrocell and coverage by leaky coax.

CDMA Umbrella Cells (Big Topic! Lots of IPR P otential!)• John Toone slides from April ‘97 PrimeCo TEM

Note on Pilot Dominance and implications

N-Way SHO and Complex SHO (Barry’s paper or parts thereof?)

Special considerations for 6-sector systems• Dennis Schaeffer 30 degree rotation idea.

• Barry’s alternating sector power idea.

Tom Ritchie email on partial overlays and notes about Singapore system.

AirTouch Back-to-Back Antenna Idea

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lemen-

• Anything worth persuing here, or is this a dead issue?

Mony’s HHO Idea• Possible modifications or motion simulations to support efficacy of design?

Start document with terminology list• SHO terms from Barry’s N-Way document.



CDMA microcells• Will Bayer’s comments on reverse link timing imbalance between microcells and macrocells (possible imp

tation in motion sim?).

of 108

MEMO: November 25, 1997


ce my

TO: Distribution Channels

FROM: Motorola CDMA Development Team

RE: CDMA Handoff Deployment & Optimization

CC:

New Stuff on 05/16/97

1.) Neighbor search window planning.

2.) Traffic planning for HHO:

• Beacons

• DAHO

• Idle-mode and TCH.

• Where to place carrier boundaries as a function of traffic density or gradient? Referenemail on “tiering” and John Voigt’s PowerPoint slide (probably not right).

3.) PN planning for microcells and in-building sites contained within macrocell coverage.

• Reference Sam Fernandez email.

4.) Inter-CBSC SHO

• Performance

• How to optimize

• Any consideration for inter-vendor?

5.) KTF handoff between Motorola and Samsung

• Mony’s HHO idea feasability?

• Still need to look at plots after technique has been identified.

6.) DAHO description and optimization strategies.

• Notes on Ec/Io statistics fromPilot Strength Measurement Message.

7.) Pilot Beacons description and optimization strategies.

• Hong Kong input.

• Notes from Barry’s slides.

8.) Future Possibilities and implications of spec changes, etc.

• Edge Sensing (note that edge sensing can be used to make DAHO more robust).

• TIA improvements a la Qualcomm/DeClerck method.

9.) Time-line and future “vision” for HHO.

PAGE 109 OF 116


lemen-

10.) Ft. Worth tests on frequency-hopping pilot beacons.

11.) Deployment “Special Situations”

• Hong Kong MTR deployment and optimization

• Singapore in-building sites with handoff to macrocell and coverage by leaky coax.

12.) CDMA Umbrella Cells(Big Topic! Lots of IPR Potential!)

• John Toone slides from April ‘97 PrimeCo TEM

13.) Note on Pilot Dominance and implications

14.) N-Way SHO and Complex SHO (Barry’s paper or parts thereof?)

15.) Special considerations for 6-sector systems

• Dennis Schaeffer 30 degree rotation idea.


16.) Tom Ritchie email on partial overlays and notes about Singapore system.

17.) AirTouch Back-to-Back Antenna Idea

• Anything worth persuing here, or is this a dead issue?

18.) Mony’s HHO Idea

• Possible modifications or motion simulations to support efficacy of design?

19.) Start document with terminology list

• SHO terms from Barry’s N-Way document.



20.) CDMA microcells

• Will Bayer’s comments on reverse link timing imbalance between microcells and macrocells (possible imptation in motion sim?).

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iquitousuming

Inter -Carrier Hard Handoff W ith Pilot Beacons (Multi-Carrier)

Inter -CBSC Hard Handoff With Pilot Beacons

Figure #11.) Ideal Inter-CBSC Hard Handoff With 4 RF Carriers (R5)

The figure below shows the solution that the Hong Kong account team is proposing. Note that carrier F1 is ubin the system due to the IS-95 “Primary” CDMA channel requirement. In addition, 1/2 of all handoffs (asssymmetrical mobility and carrier distribution per CBSC) are intra-carrier in nature.





CBSC Seam

CBSC #1 CBSC #2

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F1 PPS+TCH



CBSC Seam

CBSC #1 CBSC #2

F1 PPS+TCH

F1 PPS+TCH

F2 PPS+TCH

CBSC Seam

CBSC #1 CBSC #2



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ter-celleservecommon this dis-

on the the cus-

eet pilots.

e pro-

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lated-ating the on val-

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ing on theo forces to par-mes will

, it is

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resentide of a

DAHO and Inter -CBSC Soft Handoff

Single Cell Intra-Carrier Hard Handoff

This memo serves to provide general guidelines regarding deployment of intra-carrier (same RF carrier), in(between 2 different cells) hard handoff. Motorola currently supports this type of handoff in an effort to practive calls that traverse (different) CBSC service areas. The items in this memo are, to a great degree, sense, however some are gleaned from practical experience in our Hong Kong market. Note that “seam” incussion designates an area where handoff needs to take place between two different CBSCs.

In general, intra-carrier hard handoff performance is not as good as that of soft/softer handoff. DSD is workingproblem, however no tractable solutions have presented themselves. This should not be communicated totomer.

Hard Handoff Philosophy

Intra-carrier hard handoff detection is accomplished when the CBSC receives aPilot Strength Measurement Messagthat reveals a candidate pilot (which is an XSECT in the database) appears T_COMP dB above all active sWhen this happens, a target channel is set up in the target CBSC and then the mobile is instructed (via theExtendedHandoff Direction Message) to change the active set pilot(s). T_COMP is used as a vehicle for hysteresis in thcess with the amount of hysteresis proportionate to the value T_COMP is assigned.

Intra-Carrier Hard Handoff Optimization

Given the philosophy above, the implications are that successful hard handoff is a strong function of the depmethodology. See below for more details. In addition, there are several other factors which affect the succeshard handoff.

• T_COMP parameter: The Qualcomm mobile station demonstrates poor sensitivity (relative to simuexpected) in the seam region, especially at slow speeds. Thus, the amount of hysteresis used in comb“ping-pong” phenomenon must selected with care. In some instances, it may be that T_COMP cannot takeues any greater than 0.5 dB.

• Mobile station latency: Qualcomm has communicated to us that all versions of mobile station software arereporting T_COMP events via thePilot Strength Measurement Message. The quickest that a mobile will respondwith such an event is 250 milliseconds after the change has occurred in the RF domain. Lab measurev1.34 and v1.60 phones indicate that the delay might be 2 to 3 times as long. Thus, situations where the tof-change of the interfering pilot (i.e. target pilot) is large should be avoided.

• Infrastructure latency: Just as in soft handoff, there is a certain amount of processing and message passpart of the CBSC that must occur upon each hard handoff execution. In addition to this, hard handoff alsthe MSC and target CBSC to be involved as well. Future versions of CBSC and MSC software will attemptallelize the handoff process to the greatest extent possible, however inter-CBSC hard handoff execution tiprobably never be below 500 milliseconds.

• Extended Handoff Direction Messagesuccess rate: Given the discussion on mobile station sensitivity aboveapparent that successful delivery of theExtended Handoff Direction Message to the mobile station is difficult in“high-noise” regions (i.e. the seam). There are a few things that can be tried to help this situation. The fikeep forward traffic channel gains as high as possible, and perhaps even at their maximum values, in cells. This only works in low noise, low traffic conditions. The second is a drastic measure where the ampower devoted to the paging and synchronization channels is reduced, or even eliminated.

• Multiple handoff regions: Due to the nature of radio-wave propagation, it is possible that scenarios will pthemselves that allow for multiple handoff regions along a line, or road, separating two cellsites on either s

of 116


at wouldells, itntil thendoff

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e slight

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due to

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in

CBSC seam. Some handoffs may be completely unnecessary in the sense that a propagation condition thtrigger a hard handoff comes and goes very quickly due to mobile (vehicle) movement. For fairly large cmay be possible to use the neighbor search window to make the mobile station “blind” to the target pilot umobile is well within the overlap region1. Once again, care must be taken in using this parameter as soft hawith cells/sectors on the same side of the CBSC seam is dependent on the value that the parameter take

• Number of L2 repeats: The current intra-carrier hard handoff algorithm specifies four “salvos” ofExtended Hand-off Direction Message attempts. The number of “salvos” will soon be increased to 7. Each “salvo” is 320 millonds long2 and contains a number of attempts equal to the L2 Num_Repeats count. Increasing the numrepeats from 3 (default?) to 6 (maximum “sensible” value) may increase the message delivery rate in somway.

Intra-Carrier Hard Handoff Deployment Tips

In general, successful intra-carrier hard handoff deployment is characterized by:

• Gradual pathloss roll-off.

• Deployment restricted to “large” cells only.

• No quick NLOS3 to LOS4 transitions (target cell(s)). An example of this would be the Tai Po Harbor situatioHK.

• No quick LOS to NLOS transitions (source cell(s)). An example of this would be the situation in Tate’s Tunnel in HK where the entrance is blocked by a large vehicle and the source cell “goes away”.


• Cells far enough apart to make use of neighbor search windows to help in suppression of ping-ponging.

• Seams placed perpendicular to high traffic flow.

• No seams parallel to high traffic flow.

• No seams in high traffic areas.

• Seams in areas where traffic moves with relatively high speed such that the probability of ping-pongingextended "straddling" of the handoff zone is reduced.

• Preferably one to one or many to one transitions. By this, we mean a single target cell. We all agree thatof being in soft handoff at the source cell(s) is advantageous in that we can use the site-to-site “macrodside benefit of SHO to assist in increasing the probability that theExtended Handoff Direction Message will bedelivered successfully5. Unfortunately, going in the opposite direction, you’d have a situation where the transis one to many - definitely a situation we’d like to avoid. It might be that conditions would allow the usage otorized sites at the CBSC borders to make the target cells unambiguous and to limit the amount of SHO atder.

1. As a special note, DSD is considering basing hard handoff detection upon phase measurements madchannel elements. While solutions of this type might fall into the “tractable” category, their implementation is not in the near term.

2. See IS-95A section 6.6.4.1.3.2 and the value for timer T3m.3. Non-line-of-sight.4. Line-of-sight.5. The “Fast Pilot Shuffling” feature will allow us to specify lower values for the T_ADD parameter in the

seam cells. This should increase the probability of 2-way and 3-way soft handoff in those border cells which the topology favors pilot coverage at T_ADD Ec/Io’s.

of 116


of HHOas the

imited”.

olf;

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is.

• Deployment scheme that makes use of natural or man-made terrain features to either limit the number transitions or limit the amount of “other cell noise” coupling between the two CBSC service areas. This wtactic that the HK team was using (look at an elevation map of HK).

• No sector boundaries for a cell that cross high volume traffic paths in expected handoff locations.

• No seams in areas of weak RF coverage. The seam area should be “interference-limited” and not “noise-l

• Seams should be optimized for soft handoff

Dual Cell Intra-Carrier Hard Handoff

Mony Hassid’s idea.

From: Menich Barry on Wed, May 7, 1997 9:30 AM

Subject: Mony Hassid Disclosure - May '97

To: Hulsebosch Tom

Cc: Bonta Jeff; Bruckert Gene; Campbell Neal; Kotzin Mike; Frank Miller; Jim Aldrich GWI; Kowalewski RMenich Barry; Schuler Joe; Welk John

Tom,

This is just a little note to lobby you for a favorable treatment of Mony Hassid's patent disclosure for intra-CDMA hard handoff up for review on the 15th. The business case here for Motorola is clear. This could be a smeasure for some markets with inter-CBSC handoff problems caused by lack of spectrum (Korea? AirTouchbusiness downside is the need for some extra equipment, but as you know, we already have that problemdegree) with pilot beacons.

The technical merits of the disclosure will obviously be judged by the committee members at the time of theFor what it's worth, my opinion is that this is a tractable solution that requires no CBSC software modificatiosupport some kind of mini-trial somewhere (LA?). Mony already has some preliminary spreadsheet results afollow-up with some static simulation ideas.

In addition, I'm available for technical consultation with any of the committee members that want to discuss th

-Barry

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WHITEPAPER: Handoff Application Notes

November 25, 1997

Jim Aldrich

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1 Introduction

This paper contains various application notes as pertaining to handoff operation wiCDMA system.

2 Background

2.1 MAHO

MAHO, or Mobile Assisted Handoffs, are triggered by MS (Mobile Station) reportof neighboring signal strengths. Currently within IS-95-A and J-STD-008 an MS only scan and report on pilot PN sequences within the current in use CDMA frequThis is a substantial drawback where CDMA carriers are not ubiquitous. This inclenvironments where multiple or differing carriers are used in a system, or wheretems using differing carriers abut.

MAHO is what is normally used to add and drop pilots. It can also be used to trighard handoff.

2.2 DAHO

DAHO is the acronym for Database Assisted Handoff, originally called “last activelot” and sometimes called a “blind” handoff. It was specifically created to providmeans to handoff to an underlying analog network when the MS appeared in a near the edge of CDMA coverage. When a certain number of the active Forward TChannels (i.e. “legs”) are indicated (via the database) to be “DAHO” sectors (eachward traffic channel corresponds to a sector) a handoff is triggered to the DAHO s

Handoff Application Notes 117 of 126/usr/test/adv_sys/cdma/documentation/stolen/aldrich/ho_notes



MA

bile thelayingystemw

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ningsfulMMor-

sec-p re-nedss thee asalueOt cellsndoffec-

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with the best signal strength. This capability has been extended to include CDtargets as well as analog.

Since a non-border (non-DAHO) pilot/sector may be dropped shortly after a moarrives in a DAHO sector (thereby triggering the handoff), it is important thattarget’s coverage area completely overlaps that of the source. Where an underanalog system exists, idle mobiles are sometimes redirected to the analog s(via theGlobal Service Redirection Message on the paging channel), since a necall may immediately be handed off to the analog system anyway.

In cases where an idle mobile is not redirected, and where a mobile is handethe system (i.e. CBSC), a hysteresis timer is employed to give the system timperform any soft or softer adds or drops which might result in the mobile remaiin that sector-carrier (majority condition not met). Upon completion of a succeshard hand-in, mobile origination or mobile termination to a border sector, the will use the DAHOHysTimer database value to inhibit all subsequent DAHO bder checks for a fixed length of time.

Ideally the MS would not handoff until it reached the periphery of the current tor(s), thus increasing the erlang capacity of the cell and reducing the overlaquired. This “edge sensing” capability is currently under study but not yet planfor any release. Another means of increasing the Erlang capacity is to supprehandoff by keeping non-DAHO sectors in the active set (of pilots) of the mobillong as possible. This can be accomplished by raising the drop timer v(T_TDROP) and lowering the pilot drop threshold (T_DROP) for the DAH(hand-out) and adjacent sector/cells. As the mobile approaches the hand-oufrom the adjacent cells, it becomes harder to drop pilots, thus delaying the hauntil the mobile is more fully within the coverage zone of the DAHO capable stors.

Following are the exact majority criteria used when determining if a DAHO haoff should be attempted

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TABLE 1

3 MAHO and DAHO Techniques

When CDMA frequency coverage is not ubiquitous, or where CDMA coverends, means other than the standard MAHO pilot reporting must be emploThere are two basic methods that can be used, each with some variation. Thethe DAHO method, and the approach known as “Pilot Beacon”.

The Pilot Beacon approach uses a pilot channel only on an adjacent cell/swhich is active on the same frequency that is in use on the source cell/sectothough there may be an access and paging channel as well, there are no trafficnels. This configuration thus enables the MS to report on these locations anormal case. The end result is a handoff to an adjacent cell. This pilot beacused at the periphery of coverage of a particular CDMA frequency. This methused mostly to trigger a handoff to a different CDMA frequency but could be ufor handoff to analog as well.

MAHO and DAHO methods may both be used in a BTS/Sector/Carrier, althosuch combinations would require unusual circumstances.

3.1 Handoff to Analog

Both DAHO and MAHO trigger methods may be used to initiate a handoff to alog.

3.1.1 DAHO Method

This method works best when a full overlay of the CDMA cells occurs, as showFigure 14. However, to gain more usage out of the CDMA cells, specific semay be overlayed (completely), as in Figure 15 (which shows one sector boverlaid). Note that in both cases the analog cell may be an OMNI cell. In gethe transition may occur from a more sectorized cell to a less sectorized cell bvice-versa because the target cannot then be precisely determined. Also, the

a. There is considerable debate at this point whether or not this should be a “N”. It has been decidedallow this to be changed during process initialization via an environment variable.

1 Active Pilot 2 Active PilotsDifferent Sites

2 Active PilotsSame Site

3 Active Pilots

0 DAHO Sector-Carrier Active Pilots N N N N

1 DAHO Sector-Carrier Active Pilot Y N Ya N

2 DAHO Sector-Carrier Active Pilots Y Y Y

3 DAHO Sector-Carrier Active Pilots Y

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at isoff tobea- to do

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below show just two cells, usually there are groups of cells where frequency boaries occur.

Figure 14

Figure 15

In the configurations above, a handoff to analog will occur when the conditstated in TABLE 1 occur. The target will be the external analog sector assocwith the DAHO (has the DAHO indicator enabled) sector with the strongest pmeasurement.

3.1.2 MAHO Method

In this method a handoff to analog is triggered from a MS report of a pilot thconsidered external to the CBSC. The search for the target results in a handanalog. Typically the pilot PN measured and reported by the mobile is a pilot con (else the target is a real CDMA cell in which case there would be no needa handoff to analog). This configuration is depicted in Figure 16.

Figure 16

The advantage of this method is that the CDMA cell may be used for a longerod of time (more Erlangs) and less of an overlay of the analog cell is requiremay be that the normal overlap between cells is sufficient.) The disadvantamore equipment is required to populate the pilot beacon.

3.2 Handoff to CDMA

As in handoff to analog, both MAHO and DAHO methods may be used.

3 Sector BTSon Carrier X

3 Sector AnalogBTS


3 Sector AnalogBTS


3 Sector AnalogBTS with Carrier XPilot Beacon

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at us-t must fromseful, but

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3.2.1 DAHO Method

Since this method uses a rough geographic estimation of where the mobile is ing cell.sectors designated as DAHO, coverage between the source and targebe complete. In fact, one of the best uses of this method is to use it to handoffone carrier (frequency) to another carrier within the same cell/sector. This is uwhen the MS is travelling towards the end of coverage of a particular carrierthere exists continuous coverage of another carrier.

An example is given in Figure 17 below. A MS on carrier Z is travelling from lefright. As it travels it is able to soft handoff from BTS 1 to BTS 2. Carrier Zs covage ends in BTS 2. In order to enjoy the benefits of soft handoff between when the MS is within majority DAHO coverage of the right-most sectors of BT(shown as shaded), a hard handoff is performed to carrier X. As the mobile pfrom BTS 2 to BTS 3 it can now do so using soft handoff.

Figure 17

3.2.2 MAHO Method

This is the normal method of performing handoffs. The MS reports on neigh(pilot PNs) it has measured and deemed to be adequate in strength. Somthese Pilot PNs are resident on another CBSC, necessitating a hard handoff.this occurs the system will make every attempt to ensure the MS will be bserved by the neighboring cell. It accomplishes this by not executing the hauntil the reported signal strength of the candidate pilot is a TComp event overof the current active pilots.

Another occasion for a MAHO initiated handoff is when the MS is in a locatwhere the current carriers coverage is about to end. Here the Pilot Beacon appis used. CDMA pilot channels are set up in adjacent cell/sectors where the cucarrier would not otherwise be present. This allows the MS to measure and ron those neighbors as if the coverage were ubiquitous. Using the hard handofger criteria previously mentioned, a hard handoff will then be attempted toneighboring BTS. Since the neighbor will not have any traffic channels availwithin the current carrier, it will allocate one where it does have some available

Carriers X, Y, Z Carriers X, Y

Carriers Z Carrier Z->X Carrier X

Soft HO Hard HO Soft HO

BTS’s 1->4

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ess isptionaln the

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4 Miscellaneous

With release 6, handoff detection and handoff target selection are kept as sepas possible. Either MAHO or DAHO detection schemes can be used to trigghandoff to analog or a handoff to CDMA. In addition, alternate targets are allowDepending upon the type of failure, a retry of additional handoff targets maspecified, up to a maximum of 4. For example, a failed handoff to a CDMA tadue to no resources available may be followed by an attempt to handoff to anlog target.

Hard handoffs are always executed through the MSC, even if the source and CBSCs are the same.

5 Handoff/Database Interaction

The following sections within this chapter were part of the original design propand are included here to provide a high level logical representation of howhandoff algorithms and the database interact with each other to determine haoperation. Initial system access carrier selection is also included, as it closesembles the handoff method.

5.1 Initial System Access/Handin Carrier Selection

Figure 18 shows the inputs used for initial carrier selection following a mobile oination, page acknowledgement, or hard handin request. Input to the decisioncess is either the source sector and carrier in the case of an origination/pag(also called sector and carrier of access) or the sector and carrier identified wthe A+ Handoff Request message, in the case of a hand-in. The type of accalso used as an input. Note that in the case of a handin, the source carrier is oin A+ and may not always be present. In that event the first equipped carrier idatabase for that sector is used.

The source sector and source carrier are used to obtain aCarrier Selection Listfrom the carrier database. The access type is used in conjunction with the Clevel Call Distribution Technique parameters to return aCall Distribution Index.These parameters are then utilized to return anInward Route Index, or IRI.

The IRI is a number used to access the Inward Route Index Table. Output froInward Route Index Table is a list of routes in preferred order of selection. Thward Route Index Table is at a CBSC level, as the search strategy will likely bpeated across sectors having the same physical characteristics (i.e. carriers).

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Figure 18 Handoff/Access Target Carrier Selection

Inward Route Index Table

Source Sector

Source Carrier

Inward Route Index (IRI)

Carrier List Selection

IRI Route List

.

.

.

.

.

.

CBSC

Access Type

Notes:

1.) Source Sector is sector of access for orig or page ack, target sector for HO2.) Access Type is orig/page ack or handin3.) Source Carrier is: a) if orig or page ack, carrier of access b) if handover: if present in Handoff Request, source carrier else is first equipped Carrier in database

(Carriers)

1 1,2,3,4

2 3,4

Call Distribution Index

Carrier Selection List Edit CarrierCarrselect

Call Distribution Edit CBSC Calldist

Edit Inroute

Carrier

CBSC

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n

aven the

ile re-.

5.2 Handoff Target Selection, Source

This section outlines the handoff target selection algorithm on the source COnce an external1 handoff has been triggered, either by MAHO or DAHO meathe CBSC must select a target for the handoff.

The handoff target selection process is entered via either a PSMM (SCAP: dover Required received) (MAHO) or an indication of DAHO criteria being met

Handoff Target Selection is based on where the MS is at and what initiatedhandoff. In particular, the following information is used:

1. Source Sector(s)

2. Source Carrier

3. PN of reported pilot (MAHO), or indication none was received (DAHO)

Please refer to Figure 19 for the following discussion.

For each sector/carrier there will be an associated list of PNs. For each PN list there will be an Outward Route Index (ORI). There will be an additional enfor the case where there is no PN.

The ORI is similar to the Inward Route Index, in that it specifies a list of logroutes to try (to handoff to) in preferred order. Up to 4 may be specified. Each lcal route identifies a XASect or XCSect object. These objects contain the needed to identify the target and execute the handoff. They are managed CBSC level.

An alternate route (the next in the list) will be attempted when:

■ A handoff to the current route cannot be attempted. When attempting to hahandoff to an XASect these reasons are:

- Hard handoff not allowed for current service option- If MAHO initiated, reported signal strength is not TCOMP better tha

all active pilots- Mobile not analog capable

When attempting to hard handoff to an XCSect the reasons are:- Hard handoff not allowed for current service option- No mutual service option between mobile and target system- If MAHO initiated, reported signal strength is not TCOMP better tha

all active pilots

■ A handoff to the current route is rejected by the MSC and all retry attempts hbeen exhausted (see HHORetryCnt parameter). Retries can only occur wheMSC rejects the handoff for causes of “no resources available”, or “handoffblocked”.

1. The method for adding (and dropping) of local neighbors does not change. The mobported PN is looked for in the neighbor lists of the active sectors and if found, is added

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Figure 19 Handoff Target Selection

Outward Route Index Table

Source Sector

Source CarrierOutward Route Index (ORI)

PN (if via PSMM)

Carrier

ORI Route List

.

.

.

.

.

.

CBSC

Route Target Info

...

Outward Route Table

(noPN) 116 264 3192 4...

2 3, 4 1 1, 2

3 5

1 XCSECT-1-1

4 6, 7

5 XCSECT-3-3

2 XCSECT-1-23 XCSECT-3-1

6 XCSECT-3-4

7 XASECT-2-1

4 XCSECT-3-2

...

Edit OutrouteRoute List

Carrier

Edit Carrier/Sector Routenum

Outward Route Index Generator Table

Add/Edit Carrier/Sector Sectop Edit Carrier/Sector/BTS DAHOParms (DAHOOri)

PN ORI

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4.0 Present Tools

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4.1 Pilot Beaconfrom Dan Declerck’s taxonomy:

The definition of a pilot beacon will include a pilot channel, a sync channel, and optioa paging channel (for legacy IS-95A systems). This method is mobile assisted hand(MAHO) utilizing beacons to trigger the infrastructure to perform hard-handoff. The tger to handoff occurs when the mobile indicates to the base station when a pilot cha(that is the beacon) is TCOMP above all active set pilots.This method is backward cpatible with the 2 million CDMA phones that exist today. As we take our previous exple, and show which sites would contain beacons:

4.2 Qualcomm solution

Presently, Qualcomm sells a pilot beacon unit for approximately $20,000/sectorier which is controllable via modem. This is impractical in Japan due to: cost, tnightmare of antenna combiners, inconsistent O&M interfaces

4.3 Motorola solution

Presently, there is a working group, chaired by Thomas Appiah, that is workingseries of solutions. This group meets once a week on Fridays. Here are the follooptions:

4.3.1 Integrated Solution

Single, Primary CDMA carrier domain

Two CDMA Carrier Domain

Figure 2

Cell 1 Cell 2 Cell 3

PPP P P P

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o

-na-

This concept relies on designing a multi-carrier BBX with no receiver forreducing cost, and utilizing an entire shelf (many BBX’s with one MCC) tdo multiple carrier beacons.

4.3.2 Stand alone solution

This concept is essentially an SC601 BTS with modified TRX’s which domultiple carriers. There are difficult issues regarding low-cost O&M interfaces, with trade-offs in timeliness of delivery (drop-and-insert span vs. alog modem interfaces).

4.3.3 Paging and Sync Channel Requirements

From: Menich Barry on Wed, May 28, 1997 6:17 PM

Subject: RE: Pilot Beacon - No Paging and Sync

To: Tenbrook Keith

Cc: Campbell Neal; Menich Barry

Keith,

Well, I understand Steve’s point of view and I’m all for reduced cost beacons.However,we have J-STD-008 subscriber units to contend with. Some points:

1. I think we are getting the ability to set (via command line interface) more fieldsin the Extended Neighbor List Message with the R6 load (I will check this withCraig Reilly tomorrow morning). So, beyond the priority field, we can also specifyan RF carrier to be associated with a PN index offset. Thus, a J-STD-008 sub-scriber unit in idle-mode should be able to scan across carriers. It’s anybody’sguess if there are any perfomance issues associated with this. Note that ENLM isnot currently supported in IS-95A systems and subscriber units. When IS-95 andJ-STD-008 merge, we will still have the problem of supporting 1,000,000+ sub-scriber units that do not have this feature. I think that this will always be a naggingproblem.

2. From what I understand of the spec., we’ll still need sync/paging to redirect toAMPS/TACS/Other CDMA (Global Service Redirect Message). I am unaware ofany alternative way of doing this. Thus, at the outskirts of systems, or at operatorseams (where the operators have a service agreement) where a different technol-ogy is supported, inter-technology idle-mode handoff will need to occur.

3. According to Bob Neely, Motorola subscriber units will search for synch/pagingon the RF carrier that was being used when a live call terminated. Thus, for those(admittedly small) fraction of calls that end in the overlap region of a multi-carriertransition, the mobile will hunt for synch/paging on the current RF carrier whichmight not be the “best” PN (ie. reduced power beacon). Not finding synch/pagingjust reproduces the problem we were trying to fix in the PrimeCo markets (eg.

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subscriber units taking a long time to search all PN space and make the decisionto slew to a different carrier) by adding the channel card to the cage with the bea-con BBX. It’s possible that all, some, or none, of the other subscriber manufactur-ers will also use the same implementation.

______________________________________________________________

From: Dubberstein Steve on Tue, May 27, 1997 7:21 PM

Subject: Pilot Beacon - No Paging and Sync

To: Haddock Graham

Cc: Appiah Thomas; Berghuis Tim; Campbell Neal; Cheng T L; Chuang Ching; MaloneMike; Menich Barry; Ngan S K; Strong Dan; Tenbrook Keith; Thode John

Graham -

I know your team is working on Pilot Beacon issues as we speak. I think the results of atest done here in Hong Kong last week may impact the design.

Last week the team in Hong Kong were able to successfully test R6 multi-carrier pagingusing only the primary channel. In other words, they were successful in not using hash-ing but distributing the traffic across the carriers upon origination on the primary carrier.They were able to do this after carefully reading what R6 is capable of. This is the trafficmanagement issue that was the big barrier to removing paging and sync from the pilotbeacon.

The way I see it is that we can move forward to making a pilot beacon box with no pag-ing/sync as we now have a method of avoiding the mobile in idle mode acquiring a bea-con. All mobiles would be on the primary channel in idle mode, or hashed to carriers thathave no beacons as neighbours.

The system design will be a bit more difficult if you always must avoid beacons with nopaging/sync in idle mode, but I think it is a workable tradeoff for a much simpler beaconproduct.

I solicit the opinions of all copied on this email to check my conclusion and make sure Idid not miss something.

regards, steve

4.3.4 how to set up paging and sync channels to redirect idle mode mobiles

use CDMA_FREQ field in the Sync Channel Message

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5.0 CDMA Pilot Beacon Applications

SC-2.5.1 Application Note by Charlie Harrison

5.1 Scope

In the implementation of inter-carrier handoffs, a method is required to trigger the handoffevent as the Mobile System reaches the desired handoff zone. An adjacent Base Station(BTS) broadcasting a pilot signal on the current MS carrier, known as a Pilot Beacon (PB),is one method which has been tested, successfully deployed and is supported by Motor-ola. The technique uses the Pilot Signal as interpreted by the MS Mobile Assisted HandOff [MAHO] feature to trigger the handoff.

A Pilot Beacon can be used as a handoff trigger in at least two specific inter-carrier appli-cations. It has been successfully deployed as a means to trigger an inter-CBSC hardhandoff HHO at a seam between two CBSCs broadcasting on different frequencies. Anadditional application of PB in future SC releases is as a trigger to handoff within a CBSCbroadcasting multiple carriers.

The functionality of Pilot Beacon is addressed in this paper only as it is supported by Su-perCell Base Station System Release SC-2.5.1.

5.2 Objective

This document is intended to be used as a guide to evaluating the implementation of aMotorola Pilot Beacon to facilitate handoff between frequencies. It is not intended as sys-tem design guide or as an implementation manual. The Annexes to this document containsome installation procedures which are useful in the planning and implementation of aPilot Beacon solution and can be used conjunction with the existing CDMA CommandReference Manuals listed in the References Section (Section 5.11 on page 143).

5.3 PILOT BEACON CONCEPT OVERVIEW

To understand the concept of Pilot Beacon, refer to the simple case shown in Figure 20on page 134. This is a depiction of a Pilot Beacon scenario independent of the methodof application. Consider a mobile station on the path (moving from left to right) as showninitially being served on the left side of the diagram by carrier F1 on BTS 1. For this par-ticular scenario, the parent CBSC of each BTS is not important.

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FIGURE 20: : Simple Pilot Beacon Scenario

As the mobile station nears BTS 2, it detects the F1 pilot broadcasted by BTS 2. TheMS will continue on its path until it detects the BTS 2 pilot strength at a definable thresholdabove the MS active set, (Active Versus Candidate Set Comparison Threshold orTComp). When the TComp threshold is reached, the MS reports the pilot strength to theMobility Manager (MM) via a Pilot Strength Message Measurement (PSMM). Within theMM, the pilot PN Offset of the Beacon signal has been defined as an External CDMA Sec-tor (XCSECT) neighbor pilot for the serving cell BTS 1. With TComp criteria satisfied andthe XCSECT defined, the MM executes a CDMA-CDMA HHO with the XCSECT data tothe target cell, BTS 2, via the Mobile Switching Center (MSC). As BTS 2 is not equippedwith traffic channels on carrier F1, the target MM will allocate a traffic channel (TCH) oncarrier F2 and the handoff occurs to BTS 2 - F2.

Once the mobile transitions to F2, there are no XCSECTs in that cell’s neighbor list thatcould trigger a hard handoff back to the source BTS 2. Therefore eliminating multiplehandoffs (the ping-pong phenomenon), a scenario observed in inter-CBSC (HHOs) witha high probability of dropping calls.

5.4 PILOT BEACON DEPLOYMENT SCENARIOS

There are several instances in the deployment of a CDMA system which may make useof a Pilot Beacon to trigger a handoff. Figure 21 on page 135, provides a simple diagram-matic representation of some of the possible scenarios.


BTS 1 BTS 2

F1 Traffic Channels F1 Pilot Beacon F2 Traffic Channels

Trigger Point

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FIGURE 21: : Hard Handoff Scenarios

• Scenario A: F2 Core With F1 Ubiquitous

In densely populated areas, CDMA operators may deploy multiple carriers for additionalcapacity in regions of heavy traffic. The additional carriers may only be required in theheavy traffic areas and may not be deployed ubiquitously across the entire system, result-ing in large clusters or islands of multiple carrier sites. Referring to Figure 21, if a mobileis serviced by cells on carrier F2 and travels outside of the carrier F2 service area, a HHOmust occur from F2 to F1 or the call will drop.

• Scenario B: Simple Seam

This is the simplest of scenarios and represents two adjacent areas each serviced by adifferent frequency. This may be as a result of a Telecommunications Carrier holding dif-ferent frequency allocations/licences in different regions or at a transition between two Li-cence holders. The Pilot Beacon is used to trigger the handoff at the boundary betweenthe two carriers.

This scenario may also exist intentionally in order to make use of a Pilot Beacon to im-prove inter and intra-carrier inter-CBSC hard handoffs. There are several deploymentstrategies which make use of this concept to overcome the problems inherent to makingintra-carrier handoffs at CBSC seams.

5.4.1 Scenario A: Inter-Carrier HHOs for Partial Overlay Multi-Carrier

In a multi-carrier system, additional carriers may be requierd only in areas of high traffic.This type of deployment may result in a scenario such as shown in Figure 21 Scenario A,and will require a method to initiate an inter-carrier handoff to the ubiquitous or primarycarrier.

F1 & F2

F1 Cells Only

F1 F2

F2 Core WithF1 Ubiquitous Simple SeamA: B:

Cells

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FIGURE 22: Partial Overlay Handoff Example

The version of Multi-Carrier deployed in SC-2.5.1 (Multi-Carrier Phase I, Feature # 704)is limited in versatility and configurable options. Specifically, all system database param-eters for each Sector of each BTS are shared between the two carriers with the exceptionof the CDMA Channel List Message.

In SC-2.5.1, External Sector topology is defined per sector regardless of the source car-rier. A MS on carrier 1 uses the same sector/neighbour topology as a MS on carrier 2.This limitation will cause unnecessary hard handoffs on the primary or ubiquitous carrierif PBs are used in a partial overlay system.

Consider a system that deploys two carriers (F1 & F2), in the majority of its cells, however,only requires one carrier (F1) in some isolated outer rural areas. If a PB were to be usedto trigger HHOs from F2 to F1 as the mobile leaves the F2 coverage area, a configurationsimilar to the simple diagram shown in Figure 22 will occur at the end of F2 coverage.

In order to force a handoff from the F2 TCHs on BTS 1 to the F1 TCHs on BT2, the F2 PBmust be defined as an XCSECT in the F2 BTS 1 Neighbour List. Given the limitation inSC-2.5.1, the BTS 2 F1 PN offset would also be defined as an XCSECT. This would forceunnecessary intra-carrier HHOs from BTS 1 to BTS 2 on carrier F1.

The success rate of the resultant intra-carrier BTS 1 to BTS 2 HHOs would likely be higherthan a normal inter-CBSC intra-carrier HHO as the MS will not attempt to HHO back toBTS 1 and no ping-ponging will occur, however this configuration has never been tested.In addition, as both carriers must share parameters, optimization for both the inter-carrierand the intra-carrier HHOs may be difficult.

Pilot Beacon in SC-2.5.1 is not recommended for use to trigger and facilitate intra-CBSCinter-carrier handoffs for partial carrier overlays. Please note that a full second carrieroverlay has always been recommended for SC-2.5.1.


BTS 1 BTS 2

F2 Traffic Channels

F2 Pilot Beacon

F1 Traffic Channels

Hard Handoffs

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5.5 Scenario B: Pilot Beacon to Perform Inter-CBSC Hard Handoffs

There are several deployment strategies which make use of a Pilot Beacon to improveinter-CBSC handoffs. All strategies require the use of extra spectrum. To date, only onescenario has been tested in the field, and while plans are in progress at this time to begintesting a more complicated option, only the Primary deployment option is discussed in thisdocument.

5.5.1 Primary Deployment Option (“Spot Beacon” Approach)

The Primary Inter-CBSC Inter-Carrier PB deployment option requires that a minimum oftwo CDMA frequency channels are available to the operator. Each adjacent CBSC mustbroadcast on a different frequency thereby facilitating an inter-carrier HHO at the CBSCseam.

The diagram in Figure 23 on page 138, represents a CBSC seam area with carrier F1TCHs deployed to the left and carrier F2 TCHs deployed to the right. The larger circlesrepresent cell site traffic coverage and the smaller circles represent the coverage of thePBs with sufficient Signal to Noise Ratio (SNR) to trigger a handoff. F1 broadcasts areindicated with a shaded pattern.

The PBs are transmitted using F1 when deployed on CBSC2 cells and F2 when deployedon CBSC1 cells. The gain of the PB is reduced, limiting their coverage and providingsome hysteresis in the process by forcing a MS to travel closer to the target system beforethe PB is detected. Thus, the hard handoff is delayed, ensuring that the signal strength ofthe ADD leg on the target cell is sufficient to maintain the call. Please bear in mind thatthe setting of the Pilot strength for the Pilot Beacon should consider cell “breathing”.

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f suc-

FIGURE 23: : Primary Deployment Option

For example, a mobile moving from left to right in Figure 23, begins on traffic with CBSC1 Cell A passes through Cell B (via Soft and Softer Handoff). As the mobile enters CellC, it is in the coverage area of both CBSC 1 and CBSC 2 as B and C overlap. The mobile,however, does not see the pilot for the traffic channels on Cell C as it is transmitted on F2.Once the mobile is well into Cell C, it detects the F1 Beacon pilot and a handoff occursto F2 where there is now strong coverage from Cell C.

The benefit from this approach is that the coverage of F1 in the CBSC2 coverage areaand F2 in the CBSC1 coverage area is increased. This occurs due to the fact that the “oth-er cell” interference component (Ioc) for these frequencies is small in those coverage ar-eas. Thus, calls can travel further before running out of coverage.

Advantages:

• Reduction, or elimination, of ping-ponging.

• Selection of pilot based on best performing candidate set pilot increases probability ocessful connection at target.

• Optimization parameters now include T_COMP value and power of target beacon.

• Pilot Shuffling feature should help in improving performance.

F2 Beacons

F1 Beacons

Hysteresis Zone

F2 Traffic ChannelsF1 Traffic Channels CBSC #2

CBSC #1

CBSC #2

CBSC #1

A B C D

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ace at

mayoff.

e tech-

ze, they

• Possible relief from execution speed/latency issues. Because the handoff can take pllower T_COMP values (we no longer need to optimize to mitigate ping-ponging) andbecause ping-ponging is greatly reduced, or completely eliminated, execution speed not end up being as critical as it is today with CDMA to CDMA intra-carrier hard hand

Disadvantages:

• No guarantee that coverage will extend far enough to make this work under all conditions.Evaluation needs to be done on a case-by-case basis. Situations may arise where thnique completely fails.

• Extra antennas may be required at each site. While these antennas may be small in siwill nevertheless be subject to zoning and antenna mast wind-loading concerns.

• Requires pilot beacon hardware at seam sites/cells.

5.5.2 Requirement for Broadcasting Pilots in all Beacon Sectors

The diagram shown in Figure 23 is an extremely simplified representation of a Spot Bea-con deployment. The diagram shows the reduction in Beacon coverage as result of thereduced output power of the Beacon pilot and the resultant handoff hysteresis. Whenplanning and deploying beacons in the field, the requirement and power settings for bea-cons in each of the three sectors of a sectorized cell must be considered to account forhysteresis and coverage concerns.

Consider the two adjacent cells 2 and 5 shown in Figure 24 on page 140 and observe thepath of the mobile moving from right to left. The output power of the beacon pilot facingthe source cells has been attenuated to create the hysteresis. As a result of this attenu-ation, it is possible for the MS to travel on the path shown between the adjacent cells miss-ing the Beacon pilot on sectors 2-1 and 5-1. In order to use this hysteresis option, PBsmust also be broadcast on the sectors facing away from the source cells. The beaconstrength in sectors 2-2, 2-3, 5-2, 5-3 is increased beyond that of the source facing sectorto close the resultant gap. Increasing the pilot strength of these sectors has no adverseaffect on the beacon performance of the handoff. These requirements must be consid-ered for each beacon cell, depending on its location and application.

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FIGURE 24: : Sectorized Beacon Deployment

5.6 KNOWN LIMITATIONS

5.6.1 Idle Mode Handoffs

When a subscriber in idle mode moves into a Beacon site and detects that the beaconpilot is sufficiently stronger than that of its current BTS, it will initiate an idle handoff to theBeacon site. This handoff occurs with no infrastructure interaction and therefore there isno opportunity for the infrastructure to actively direct the mobile to the traffic channel car-rier on the target system.

The Beacon site can be configured to passively direct the mobile to the traffic channel car-rier in SC-2.5.1 with the CDMA Channel List Message if the site is equipped with a Pagingand Synchronization Channel which require the addition of hardware. If the CDMA Chan-nel List Message is implemented, the subscriber unit will quickly retune to the traffic chan-nel frequency, if not it will temporarily lose service until the traffic channel frequency isacquired. The details of each of each scenario are discussed below.

5.6.2 Mobile Re-direction with CDMA Channel List Message

A Paging Channel and a Sychronization Channel can be equipped for the Beacon sitewith the addition of an overhead Multi-CDMA Channel (MCC) card to the CDMA ChannelProcessor (CPP) PB shelf and subsequent traffic channel enabling. The CDMA Channel

2-1

2-2

2-3

5-1

5-2

5-3

Source Cells on F1CBSC 1

Beacon Pilots on F1

Path of Mobile

Target Cells on F2CBSC 2

Cell 2

Cell 5

Minimum Extentof F1 Coverage

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List Message on the paging channel and the Sync Channel Message body on the syn-chronization channel can then be used on pilot beacon carriers to force the subscriber unitto re-tune it’s frequency synthesizer to the TCH carrier.

After initiating an idle handoff, the subscriber unit has changed its active set pilot to thebeacon site and it will begin to monitor the beacon Sync Channel Message. TheCDMA_FREQ field is read from the Sync Channel Message body and the CDMA ChannelList Message Body. The Subscriber unit determines that CDMA_FREQ has changedsuch that a frequency retune is required. The subscriber unit then retunes from the bea-con pilot to traffic channel pilot within the current cell and begins monitoring synchroni-zation channel, etc. This flow is described again in even further detail in Section 6, “IdleHandoff Solution Description,” on page 153 of this document.

5.6.3 Mobile Behavior with Loss of Service

In the absence of any direction, the mobile is left to re-acquire the traffic channel equippedcarrier on its own. After the idle handoff, the mobile will attempt to acquire the pagingand synch channel on its current carrier (Beacon site), and will fail and enter the SystemDetermination Substate of the System Initialization State with a System Lost Indication asdefined in the IS-95A and ANSI-J-STD-008 specifications. Upon entering this state themobile should attempt to select the same system that was lost (PB frequency). The mo-bile will successfully acquire the PB Pilot and will again fail with no Paging and Synchro-nization Channels.

The number of times the mobile will cycle through this loop is not defined and is currentlyunknown. Eventually, the mobile will enter the Custom System Selection Process whichis also very loosely defined in both specifications and is left to the mobile station manu-facturer. From the Custom System Selection Process the mobile should identify the car-rier equipped with traffic channels as the correct system to use.

In both the IS-95A and ANSI-J-STD-008 cases, the end result is a visible temporary lossof service. The specifications do not stipulate minimum time requirements to regain ser-vice and the length of the period of lost service will vary with system type and subscriberunit model, version and configuration.

5.6.4 Recommendations

Reports from the current ANSI-J-STD-008 field implementations are that the mobile cantake from 3-10 seconds to re-acquire service after handing in to the PB site. These re-sults are based on limited testing and it is therefore recommended that they be consideredapproximate. It is highly recommended that before choosing to depend on the mobile tore-acquire the traffic channel carrier, field testing be conducted on the specific system withtypical handsets in various configurations.

The advantage of deploying the Paging and Synch Channels is that idle handoffs occurwith no interruption of service to the user. This advantage, however, may be weighedagainst the financial/business implications of equipping all beacon sectors with MCCs andshould be considered on a case by case basis.

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ode

5.7 Subscriber Capacity Limits

Pilot Beacon makes use of second carrier capability of SC-2.5.1. If the second carrier isrequired for traffic purposes, a Pilot Beacon implementation with Motorola equipment isnot possible with SC-2.5.1.

5.8 IMPLEMENTATION

Pilot Beacon has been implemented in various markets with Motorola equipment by mak-ing use of the Multi-Carrier Phase I functionality in SC-2.5.1. The second carrier capabilityof each CDMA BTS is used to transmit the beacon pilot. The source of the Pilot Signal ina PB triggered handoff is unrelated to the active call and it is possible to make use of PilotBeacon Generator manufactured by a third party.

5.8.1 Hardware Requiremets

5.8.1.1 Motorola PB Hardware Requirements

Pilot Beacon is possible in SC-2.5.1 with Multi-Carrier Phase I functionality. The secondcarrier capability of each CDMA BTS(4850, 2450 or 9600) is used to transmit the beaconpilot signal. Hardware requirements for PB implementation, therefore, are the same asthose required for a second carrier installation with a few exceptions.

For use as a general guide, the following hardware is required for a BTS second cage/second carrier installation:

• 1 CDMA Carrier HdW Kit (Includes CCP Shelf, GLIs, BDC etc)

• 1 BBX for Redundancy (if desired)

• 1 BBX for each beacon sector

• 1 Sector LPA for each beacon sector

• 1 Duplexer for each beacon sector

• Overhead MCCx8 cards as required per sector. Please refer to Section 5.6.1, Idle MHandoffs to verify the requirement for Paging and Synchronization Channels.

• Appropriate cables and brackets.

In addition to the hardware for a second carrier installation listed above, attenuators arerequired for each sector. Please refer to Annex 5.12.1 on page 143 for the details of therequirement attenuators and the recommendations for setting beacon power levels.Please refer to the CDMA Equipment Planning Guide, item [4] in the references sectionfor further details on BTS equipment planning.

5.8.1.2 PB Generator

The source of the Pilot Signal in a PB triggered handoff is unrelated to the active call andit is possible to make use of Pilot Beacon Generator manufactured by a third party. Thesource side MM database is configured no differently than if the Pilot Signal originatedfrom a Motorola BTS.

Any such PB Generator, however, would not be a Motorola CBSC managed device and

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URL;

would require external maintenance tools. In addition, unless the PB Generator can beequiped to transmit Paging and Synchronization Channels with a configurable CDMAChannel List Message or Global Service Redirect Message, the Idle Handoff Problem dis-cussed in Section 5.6.1 on page 140 will prevail.

5.9 Installation and Optimization

The details of equipment installation, database provisioning and optimization are beyondthe scope of this document. Please refer to the documents in the references section orthe Annexes to this document for examples and details regarding these issues.

5.10 Beacon Span Requirements

An additional span is not required for PBs installed in the second CCP Shelf of the 2450,4850 and 9600 BTSs. The existing implementations of PB use only one T1 in all sites.The second CCP shelf transmits overhead channels only and there is no reason to addadditional timeslots (as all traffic is forced to the first cage). In addition, the pilot beacondoes not need it’s own LAPD, it is a slave to the MGLI that terminates the original spanand receives/sends all information to the Transcoder via that card.

In the implementation of true mini-multi carrier (both carriers used for traffic) timeslots canbe stripped from the original T1 and used in the second cage for traffic. A second spanis only required for the second carrier to relieve span congestion.

5.11 REFERENCES

[4] CDMA Equipment Planning Guide

[5] CDMA Second Carrier Installation SC2400/SC4800 Technical Education and Docu-mentation (TED) 68P04245A14.

[6] CDMA System Commands Reference -TED 68P09226A24-3

[7] SC 2400/4800/9600 CDMA Cellular System Administration - 68P09226A21-6

[8] SC - 2.5.20.0. Release Notes Book Version 0.7

Please note :

• this document as well as items [4] and [8] can be found on the World Wide Web at the

http://scwww.cig.mot.com/people/cdma/PjM/product/release_info/rel_5/rel_5.html

• items [5], [6] and [7] can be found on the World Wide Web at URL;

http://www.cig.mot.com/CIG/IviewDocs/cdrom2/cci/www/html/sc_pfa.html

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s).

5.12 SC-2.5.1 Pilot Beacon Installation

This section contains a collection of detailed notes which are useful in the implementa-tion of Pilot Beacon. In general, the following steps are required to install Pilot Beaconsto a Motorola system.

• Install required Pilot Beacon hardware.

• Provision Pilot Beacon hardware in database (not required if external PB Box).

• Modify gain settings for pilot beacons.

• Define XCSECT devices and make database Neighbourlist and and Sector Topologychanges at Source CBSC.

• If required, migrate CBSCs to different frequencies (for Inter-CBSC, Inter-Carrier HHO

• Modify subscriber unit configurations with 2nd carrier capability

5.12.1 BTS Modifications - Beacon Settings

WPD Contact: Devesh Patel, [email protected], skypage 1570165

This section describes the procedure to change the Bay Level Offset which is required toattenuate the Beacon Frequency Power out. It is recommended to attenuate the bea-con sectors pointing away from the HHO seam by 6 dB and those towards the seamby 20 dB. This will potentially reduce HHO ping-ponging by reducing hysteresis zonenear the seam while at the same time increasing beacon coverage area away from theseam thereby minimizing the probability of MS failing to detect beacon pilot (please seesection 5.5.2 of the main document).

For proper functioning of “Pilot Beacon” aided HHOs, the second carrier (also known asthe Beacon Frequency) needs to be transmitted with lower power as compared to the Pri-mary carrier. Since the current release allows changing “SIF Pilot Power” only on a persector basis, and not on a per carrier basis, an alternative method is needed to controlcarrier power individually. Motorola has devised a procedure to accomplish this by chang-ing the Bay Level Offsets (BLOs) in the downlink for each Tx branch (BBX). In order toreduce power out for a carrier, the Bay level offsets need to be increased since they rep-resent gain value. The BLOs reside in a calibration file that resides on MM.

What follows below is an outline on how these BLOs are stored in a cal file and how theyneed to be changed. Thereafter, the various steps are listed in systematic order. The pro-cedure is such that it can be applied without a need to know which of the two carriers isprimary or beacon. This should ease in the calibration procedure and facilitate automaticscripting to implement changes.

Key Points

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• A 2-carrier BTS contains 8 BBXs. For the purpose of Pilot Beacon aided HHOs, for easector site, the first four BBXs are referred to as those supporting the Primary frequencthe remaining 4 as those supporting the beacon frequency. It is essential that all of thBBXs/Tx paths/slots are calibrated with the LMF for each 2 carrier BTS and that the csponding Cal files are uploaded on the MM for each 2 carrier BTS. It is also essentiacalibrate each of these eight slots with both the primary as well as the beacon freque

• The uploaded Cal file for each BTS resides on the MM under /screl/active/loadable/btdirectory and is named with suffix ".cal" (eg, mm2:/screl/active/loadable/bts-108/bts-108.cal)

The modification of the BLOs can be automated through the use of a script which, throughmarket implementation, has already been created. The script may be available from theWPD contact for this section. What follows is a description of the BTS cal. file which isuseful if manual editing is required. In addition, a Step-by-Step procedure for editing thecal files with the script is provided.

5.12.2 BTS Calibration File Description.

• For a 2-shelf SC 4850(E) frame, each Cal file contains Calibration data points for 8 differentBBX slots. Each slot contains 90 Calibration points - first 30 for the 3 Tx branches, nefor Main Rx branch for 3 sectors and last 30 for Diversity Rx branch for 3 sectors. Eacpoint is represented by two parameters -- Frequency and corresponding Bay Level O(BLO). Hence the 90 cal points for each slot are arranged in an array of 180 elementsodd numbered elements represent Frequency and the even numbered ones represenEach array element in the cal file is indicated as C[x]. So, 20 the array element will beshown as C[20].

• Each BLO is entered in the cal file after translating the dB value to integer as follows:BLO_in_cal_file = [(BLO_in_dB) + 150] * 100 (Eg, 45 dB <->19500)

• In a 2-carrier, 3-sector BTS cal file, for the slots 1 and 5, array elements 1 through 20sent “valid” section to include Tx cal points. The remaining 21 through 60 are dummypoints. Similarly, for slots 2 and 6, array elements 21 through 40 represent “valid” secwhile array elements 41 through 60 do so for slots 3 and 7. For slots 4 and 8 that are redundant BBX, all 60 cal points from 1 through 60 represent “valid” section.

• For a 2 carrier BTS, it is essential to have at least first four cal point elements filled incal data in each “valid” section to represent the two frequencies. It is also essential toinclude the two frequencies in an ascending order. Eg, array elements C[21] and C[2slots 2 and 6 should indicate 425 & 450 (and not 450 & 425). The next 16 cal points adon't care within each valid section of a slot (these may become necessary for more tcarriers per BTS)

• In order to reduce effective power out for a beacon frequency, only Tx cal points needmodified. The Rx cal points (i.e. elements C[61] through C[180] ) for each slot shouldleft as they are. Further, these changes will have to be made only for slots 5-8. This is

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be

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because beacon frequency is supported by second shelf (last 4 slots) of each BTS. Fshelf (first 4 slots) in each BTS supports Primary frequency and no changes are needthere.

• For slot 5, 6 and 7, the BLO for both frequencies need to be increased by 600/2000 totively decrease beacon power by 6/20 dB. In general, it is highly desirable to change 10 BLOs that are present in the òvalidó section for each of these slots(eg, alternate elfrom C[22] through C[40] for slot 6). The reason behind changing BLOs for both the fquencies is that if, after making all the cal file changes, it were decided to move a 2-cBTS from 1 CBSC to the other, it can be done so, transparently, without any need forther change in the cal files. For slot 8, all the BLOs corresponding to both frequenciesto be increased by 600/2000 to effectively decrease beacon power by 6/20 dB (i.e., altelements from C[2] to C[60]).

5.12.3 Step-by-step procedure to change Bay Level Offsets with Script:

• Each 2 carrier BTS need to be calibrated by a CFE with a LMF. All the 8 BBXs shouldcalibrated with both the carrier frequencies.

• Place the cal files obtained from step1 on proper MM under /screl/active/loadable/bts

• Open an xterm on the MM machine and change the directory to where the cal file to bmodified resides. Run the script provided to change the bay level offsets for the beacrier. The script will be provided with the applicable modification procedure.

5.13 Database Provisioning

WPD Contact: Mike Seymour, [email protected], skypage # 1570196

5.13.1 GENERAL ADD SECOND CARRIER COMMANDS

This section describes the commands and arguments needed to provision a second car-rier. The commands listed below do not form a procedure, they are simply provided asa reference and should be used in conjunction with the CDMA Command Reference Man-uals. Item [5] in the References Section of the Main Document (Section 5.11 onpage 141) provides details of a second Carrier installation and provisioning.

Each command section is listed in bold. The commands are to be entered via a CLI areshown in italics. The commands are followed by verification command references and abrief description.

DEFINE A NEW LOGICAL CARRIER FOR THE CBSC>EDIT CBSC-x CARRIER!>DISPLAY CBSC-cbsc# CARRIERADD CARRIER Command to SECTOR>"ADD CARRIER-bts#-sector#-carrier#"(A CARRIER defines an instance of a CDMA channel within a sector. The walsh codes forCDMA channel are provisioned as part of provisioning the CARRIER)>"DISPLAY BTS-bts# CHANCONF"

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shelf

chan

EDIT the CARRIER of each sector in the BTS Channellist>EDIT CARRIER-bts#-sector#-carrier# CHANNELLIST CHAN1=carrier#>DISPLAY BTS-bts# CHANNELLISTADD SCH Command>"ADD SCH-bts#-sector#-carrier#-sch#",Add a synch channel to the CDMA channel.>"DISPLAY CARRIER-bts#-sector#-carrier# OVHDGRP"ADD PCH Command>“ADD PCH-bts#-sector#-carrier#-pch#”Add a paging channel to the CDMA channel.>"DISPLAY CARRIER-bts#-sector#-carrier# OVHDGRP"ADD ACH Command>"ADD ACH-bts#-sector#-carrier#-pch#-ach#"Add an access channel to the CDMA channel.>"DISPLAY CARRIER-bts#-sector#-carrier# OVHDGRP"ADD MDM Procedure>"ADD MDM-bts#-mdm#"An MDM is added for each configured modem frame shelf. T2 CDMA only supports a single CDMA configuration. Adding the MDM provisions theappropriate number of BDC's.>"DISPLAY MDM-bts#-mdm# MDMCONF"ADD BBX Procedure>"ADD BBX/BBXR-bts#-bbx/bbxr#"Add the BBX to a CDMA MDM.>"DISPLAY MDM-bts#-mdm# MDMCONF"EDIT MDM LINK Command>"EDIT MDM-bts#-mdm# LINK CARRIER=carrier#”Assign a logical carrier to the shelf.>"DISPLAY CARRIER-bts#-sector#-carrier# CHANCONF"ADD GLI (Remaining GLIs) Procedure>"ADD GLI-bts#-gli#"Add remaining GLIs (3 - 8 and 11 - 16) and/or MGLIs (9 - 10) to existing BTS. For a BTS,BTSLINK #1 must be provisioned before any GLIs can be provisionedwithin the site.>"DISPLAY GLI-bts#-gli# GLICONF"ADD MCC Procedure>"ADD MCC-bts#-mcc#"Add an MCC device to the MDM. The mode of the device (traffic only or traffic and overhead nels) is specified on the command line.>"DISPLAY MCC-bts#-mcc# MCCCONF"EDIT Overhead Channel LinkagesAssociate the overhead channels with a servicing MCC card.EDIT SCH LINK Command>"EDIT SCH-bts#-sector#-carrier#-sch# LINK CE=bts#-mcc#-1”Associate the SCH with an MCC channel.>"DISPLAY CARRIER-bts#-sector#-carrier# OVHDGRP"EDIT PCH LINK Command

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>"EDIT PCH-bts#-sector#-carrier#-pch# LINK CE=bts#-mcc#-0”Associate PCH with an MCC channel.>"DISPLAY CARRIER-bts#-sector#-carrier# OVHDGRP"EDIT ACH LINK Command>"EDIT ACH-bts#-sector#-carrier#-pch#-ach# LINK CE=bts#-mcc#-0"Associate ACH with an MCC channel.>"DISPLAY CARRIER-bts#-sector#-carrier# OVHDGRP"

5.13.2 Mobile Programming

All subscriber units to be used on the system must be programmed with all possible fre-quencies on the system. This is to ensure that during the Mobile System Selection Pro-cess, the Mobile recognizes and can select the traffic channel bearing carrier. Forexample, if a PCS system with two CBSCs were to broadcast F=425 on CBSC 1 andF=450 on CBSC 2 in order to facilitate Inter-CBSC Inter-Carrier HHOs, then both frequen-cies/channels should be programmed in the phone.

The technique for programming mobiles will vary with system (IS-95A or PCS) and mobilemanufacturer.

5.13.3 Source Database Configuration

For each source sector it is important the following XCSECT and Neighbor list additions/changes are made.

5.13.4 Neighourlist Additions

Due to the increased range of the border cells, additional neighbors must be added to theneighbor lists. In general, all sectors from pilot beacon cells should be added to theirsource neighbor lists. This will insure that mobiles initiating calls within the coverage ofthe border cells can hard handoff to any cell after traffic channel assignment and that mo-biles that travel past the reduced beacon spot beams are captured by the rear pointingsectors (see Section 5.5.2 on page 137 in the main body of the document). This shouldstep occur before detailed drive testing and optimization.

It is imperative that the rear sectors of each beacon cell are included in the neigh-bor list of hard-handoff cells and the XCSECT table reflects these additions.

5.13.5 External Sector Topology

As PB Handoffs make use of SC infrastructure CDMA-CDMA HHO Execution, XCSECTobjects must be established for the beacon pilot’s PN Offset Index.

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ANNEXES - FIGURE 25: XCSECT Example

Referring to Figure 25, consider that the cells equipped with Pilot Beacons on the targetside are configured as shown in Annexes Table 2 on page 150. Note that the PN settingsfor this table are independent of the source of the Pilot signal (i.e. Motorola Beacon or PBBox)

Again referring to Annexes- Figure 25, the Source (CBSC 1) Side handover candidateneighbour sectors (only external sectors are listed) for sectors 23-1 and 24-1 would beconfigured as in Table 4 on page 151. Although this topology also contains internal sec-tors/neighbours, they have not been included in this example.

For each HHO, the configuration data information required for each handover candidatesector specified on the Topology Map must be accessible on the Source MM. In order to

Table 2: Pilot Beacon PN Configuration

SECTOR - IDbts-Sector

Pilot PN(PILOTPN)

SECTOR - IDbts-sector

Pilot PN(PILOTPN)

SECTOR 8-1 230 SECTOR 5-1 240



8-1

8-2

8-3

5-1

5-2

5-3

Source Cells on F1CBSC 1

Beacon Pilots on F1

Target Cells on F2CBSC 2

BTS 8

BTS 5

Minimum Extentof CBSC 1

BTS 23

BTS 24

F1 Coverage

23-1

24-1

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provide the accessing of this information at the source MM, the XCSECT device is creat-ed. A XCSECT Device is a device which contains the configuration data information ofthe CDMA handover candidates sector which are not under control by the Source MM.The device provides some of the information required to execute the HHO via the A+ in-terface. For example, the BTS and SECT fields are used to populate the Cell ID in the A+Handoff Required message from the BSS to the MSC.

For each of the external sectors listed as neighbour candidates, there must be a corre-sponding XCSECT DEVICE. For this particular example in Table 3 on page 151, onlytarget BTS and Sector are listed along with the XCSECT PN as the remaining fields in theXCSECT tables are not relevant to this discussion.

In SC-2.5.1, external sector topology is defined per sector regardless of the source carri-er. A MS on carrier 1 uses the same sector/neighbour topology as MS on carrier 2.

5.13.6 Optimization Techniques

What follows are a few techniques that can be used to optimize hard handoff borders.

Table 3: XCSECT Data

XSECT ID BTS SECT Pilot PN

XCSECT 2-1 8 1 230

XCSECT 2-2 8 2 232

XCSECT 2-3 8 3 234

XCSECT 2-4 5 2 242

XCSECT 2-5 5 1 240

XCSECT 2-6 5 3 244

Table 4: Source Side External Sector Topology

SourceSECTOR - ID

NeighbourSECTOR - ID

PrimaryNeighbourPilot PN

SECTOR 23-1 XCSECT 2-1 Yes 230








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5.13.6.1 Increasing Coverage/Overlap

4. First step is to adjust the source TCH Sifpilot power level to provide coverage into the bespot. The range for this adjustment is 33-37 dBm. This should only be done after analyshows poor coverage. After increasing the Sifpilot power the neighbor lists should be re-ined to insure that newly created neighbor pairs are placed in the neighbor lists.

5. If the coverage across the seam is inadequate, the beacon power should be increased bthe beacon adjustment script in 2 dB increasing increments.

6. The overlap at the seam should provide a handoff region where the source is > -10 dB aget is >-10 dB after the transition has taken place.

7. Finally, if the region is still not satisfactory, lower Tcomp from the standard value.

5.13.6.2 Reducing Bouncing

1 First step is to adjust the source TCH Sifpilot power level to provide coverage into the bespot. The range for this adjustment is 27-33 dBm. This should only be done after analyshows too much coverage. The region should be re-driven in order to insure that coveraexists for the entire sector.

2 The second method is to decrease the pilot beacon in the inwardly pointing sector. Theshould be redriven in order to insure that the overlap still occurs at good Ec/Io levels.

3 The third method is to increase the Tcomp from the standard value in 1 dB steps. This wonly be effective if the overlapping coverage is good (in which case method 1-2 should preffective reduction of the bounces)

5.13.6.3 Drive Testing and Trouble-Shooting Suggestions

The section provides an outline of scenarios that may encountered during early drive test-ing of recently installed PB sites. For the purposes of explanation, consider that there isa seam between a “North/East CBSC” region and “South/West CBSC” region. Supposethe North region operates on the “North frequency” and the South operates on the “Southfrequency”.

To diagnose events at the seam, assume the mobile viewpoint and drive across the seam.What you see will probably fall in to one of the following scenarios

5.13.6.3.1 Description Beginning

A mobile originates in the South/West region. It is able to do this because the mobile hasbeen programmed with the North/East frequency as primary and the South/West frequen-cy as secondary or vice versa. The mobile proceeds in a North/East direction and ap-proaches the seam area. The pn of a beacon (a pilot with offset index 51, or other, callit “beacon pn index”) in the North/East region transmitting a pilot at the South/West fre-quency becomes visible to the mobile and is reported on the DM F9 screen. Pilot “beacon

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pn index” exceeds Toad and the mobile sends a PSMM. There is no action taken by theXC for this event. Several things may happen next:

Perfect outcome:

5.13.6.3.1.1 Soon pilot “beacon pn index” is T_comp higher than the best active set pilot,and an inter-carrier hard handoff of the mobile to the same pn index but on the North/East frequency takes place. The mobile is directed (via Ex. Handoff Direction) to theNorth/East channel number and given a new walsh cover index for the forward channel.A single moderate click may be heard on the mobile side. The mobile quickly goes intosoft handoff with various North/East site pns.

Not perfect, but acceptable:

5.13.6.3.1.2 The events of paragraph section 5.13.6.3.1 occur and then:

the new pilot on the North/East frequency falls T_comp below a now-visible South/Westregion site transmitting a beacon on the North/East frequency. The XC sends the mobileback via inter-carrier hard handoff to the South/West Site. Propagation conditions contin-ue to change and the mobile sees the North/East site, South/West frequency beaconagain and inter-carrier hard handoffs back one more time, for a total of 3 HHOs in crossingthe seam region. From our mini-test area at I-355 and Lake, this seems to be a typicaloccurrence.

Successful, but poorer audio:

5.13.6.3.1.3 The events of paragraph section 5.13.6.3.1 occur and there is no quickevolution to the T_comp event. Instead, the mobile sees another distant South/West fre-quency pilot (with traffic) along with the beacon. The mobile goes into SHO with this pilotand is not close enough to the beacon site to trigger T_comp (the beacon is not T_compbetter than the active set). If inter-CBSC SHO were in place, the mobile would now be inSHO with what is the North/East beacon site. Instead the North/East beacon interfereswith the mobile and causes multiple frame erasures. Finally, the beacon is T_comp bet-ter than all active set members and the inter-carrier HHO takes place. The audio qualitymay or may not immediately improve.

Unsuccessful, neighbor list:

5.13.6.3.1.4 The events of paragraph section 5.13.6.3.1 occur, followed by T_comp.However, the beacon pn index is not in the neighbor list, so no HHO is allowed. Eventu-ally, the mobile RF losses on it's South/West frequency active set.

Unsuccessful, beacon ok but traffic dead:

5.13.6.3.1.5 The events of paragraph section 5.13.6.3.1 occur, followed by a handoffdirection message to a channel on the North/East frequency. Unfortunately, in this sce-nario, pilot, paging, sync and traffic at this sector on the North/East frequency are all

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dead because there is a site problem and there is no alarm to inform the system opera-tor. The mobile HHOs to the North/East frequency but finds no live channel. It has beensuggested that this problem be avoided by shutting down the beacon if there is no poweron the traffic channel.

Unsuccessful, poor audio and no handoff:

5.13.6.3.1.6 The events of paragraph section 5.13.6.3.1 occur, followed by an evolutionsimilar to paragraph 3, but there is no T_comp event before the mobile fade timer expiresand the mobile RF losses. To avoid this, try lowering T_comp.

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6.0 Idle Handoff Solution Description

As described in Section 5.6.1, “Idle Mode Handoffs,” on page 138, idle-mode handoffproblems have been observed that cause lapses in system acquisition by the subscriberunit. This section outlines the only solution for the problem in SC-2.5.1. The solution hasbeen tested in several Motorola CDMA markets and provides relief from the idle-modehandoff problems associated with Pilot Beacon intiated handoffs..

The nature of the solution involves a characteristic of the SC-2.5.1 software load that re-quires that all carriers at a BTS/sector transmit identical parameter information on syn-chronization and paging channels. In particular, the CDMA Channel List Message on thepaging channel and the Sync Channel Message body on the synchronization channel canbe used on pilot beacon carriers to force the subscriber unit to re-tune it’s frequency syn-thesizer to the over-laid (non-beacon) RF carrier.

Consider the simple diagram below (Figure 26, “Subscriber Unit Traversing CBSCSeam,” on page 156) which depicts hypothetical control flow for subscriber unit idle-modeactivity. CBSC #1 (cell #1) and #2 (cell #2) are to the left and right of the seam respective-ly. Traffic channel RF carriers F1 and F2 are also deployed to the left and right of the seamrespectively. A subscriber unit, in idle-mode, is traversing the seam from left to right andis currently monitoring the paging channel for CBSC #1 on F1.

The sequence of events is as follows:

• Subscriber unit monitors pilot Ec/Io and paging channel FER of current idle-mode actset1 cell (cell #1) on frequency F1.

• Subscriber unit determines that coverage of current active set cell (cell #1) is no longequate and that beacon cell pilot (also F1) is superior in terms of Ec/Io.

• Subscriber unit changes active set pilot to beacon cell (cell #2) and monitors synchrotion channel.

• Subscriber unit recovers the CDMA_FREQ field from the synchronizationSync ChannelMessage body.

• The subscriber unit then begins monitoring the paging channel (on F1) at the beacon(cell #2) and recovers the CDMA_FREQ field from theCDMA Channel List Message body.

• Subscriber unit determines that such that a frequency retun

required.

• Subscriber unit retunes from F1 (beacon) to F2 (TCH bearing pilot) at cell #2 and begmonitoring synchronization channel, etc.

1. J-STD-008 uses the identical terminology (e.g. “active set”, “neighbor set”, etc.) to describe both idle-mode and tch-mode pilots.

CDMA_FREQS CDMA_FREQR≠

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FIGURE 26. Subscriber Unit Traversing CBSC Seam

6.1 Idle Handoff Equipage Procedural Detail

Given that the beacon sites are already provisioned, we will only have to add one over-head MCC for each sector that is involved in the beacon hand-off. The following is anoutline of the procedure to add and equipe the overhead MCC without equipping any traf-fic channels (critical to the implementation of Pilot Beacon). After the MCC-8 card hasbeen physically installed in the CCP Shelf;

• Add a synch channel with the ADD SCH command, for example:

add sch-bts #-sector #-carrier #-sch #

Scan currentactive pagingchannel.

Start

Currentpaging channel coverage exhausted?

Obtainneighbor (F1 beacon) cell sample

Beaconcell coverage established (F1)?

No

Yes

No

Yes

No Yes

Scan other PNs, possibly other RF carriers.

Acquire new cellsynchronization channel

Acquire new cell paging channel

Current RFcarrier.EQ. RFcarrier inCDMA Chan List Msg?

Subscriber Unitcamps on beaconsignal (undesiredoutcome)

Subscriber Unitretunes to RFcarrier inCDMAChan List Msgand monitorssynch/paging

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, for

ed)to1 and only

• Add a paging channel with the ADD PCH command, for example:

add pch-bts #-sector #-carrier #-pch #

• Add an access channel with the ADD ACH command:

add ach-bts #-sector #-carrier #-pch #-ach #

• Add the mcc with the ADD MCC command. The srchans should be linked to 0-0-0-0which inhibits all channel elements. This allows the addition of the MCC without usinvaluable timelslots.

add mcc-bts#-sector#-mcc# SRCHAN0=SRCHAN1=SRCHAN2=0-0-0-0 SRCHAN3=0-0-0-0 SRCHAN4=0-0-0-0 SRCHAN5=0-0-0-0 SRCHAN6=0-0-0-0 SRCHAN7=0-0-0-0MODE=ONEOCG MCCTYPE=MCC8

• Link the synch, paging and access channels to the MCCCE with the EDIT commandsexample;

edit sch-bts #-sector #-carrier #-sch # link ce=bts #-mcc #-ce #

edit pch-bts #-sector #-carrier #-pch # link ce=bts #-mcc #-ce #

edit ach-bts #-sector #-carrier #-pch #-ach # link ce=bts #-mcc #-ce #

• Link the channel list of the PB site (for which the overhead channels were just equippthe carrier equipped with the traffic channels. For example, if the site has traffic on Fthe beacon is on F2, then the channel list message on the beacon site should inlcudeF2. This is done with the EDIT CARRIER command, for example;

edit carrier-bts#-sector#-carrier# channellist chan1=1

• Move the MCC from a PRECUT state to OOS_MANUAL by typing:

cutover mcc-bts #-mcc #

• Activate the MCC by typing:

activate mcc-bts #-mcc #

• Enable the MCC by typing:

ena mcc-bts #-mcc # unc

There is a possibility that the MCC may not come INS. If that happens, it is most likely dueto the gli_dev_map not getting updated real-time. In order to "work-around" this problemif it is seen, simply disable/enable the cage controlling gli.

The above changes will link the beacon's channellist to the frequency of the traffic cageand allow the mobile to re-tune to the frequency specified in the message. In addition,SyncCdmaFreq parameter in the Sync Channel Message will get set to the same frequen-cy as is specified in the Channellist Message. So, a mobile powering-up in the zone couldre-tune without having to acquire paging.

6.2 Pilot Beacon Output Power

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Since the addition of paging and synchronization channels to the beacon carriers, will re-sult in an additional 2.67 dB of extra output power, it might be necessary in some situa-tions to reassess beacon output power and adjust (upward) accordingly. The expectationis that this should be a rare occurrence nevertheless, field engineers should be alert forundesirable changes in handoff locations. These changes, should they occur, will mostprobably manifest themselves between beacon sites.

6.3 Expectation for Empirical Results

The desired result from deployment of this technique is quicker response time by the sub-scriber unit in acquiring the synch/paging channels of the TCH-bearing RF carrier at thetarget cell during a seam transition. With the current deployment, the Qualcomm subscrib-er unit will attempt to scan all PN-space on the current carrier (while at the beacon site)before aborting and retuning to another carrier for system acquisition attempts. This hasbeen monitored by both customers and Motorola personnel and is estimated to take noless than several seconds. During this period, the subscriber is inhibited from placing callattempts or receiving pages.

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6.4 Static Simulator

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6.5 Partial Overlay

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7.0 FutureTools

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7.1 Frequency Hopping Pilot Beacon

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Frequency Hopping Pilot Beacon

May xx,1997

by

Scott M. HallSenior Staff EngineerJon St.Clair, Senior Staff Engineer

________________________________________________________________________Motorola Confidential Proprietary

Abstract:

• Frequency Hopping Pilot Beacon reduces costs by eliminating multiple pilot beaconeach sector of a BTS. The frequency hopping is very very slow and is not used to spread theas in a CDMA-Frequency-Hopping system A single TX pilot beacon is scanned between athe pilot beacon frequencies in a sector. The time spent on each frequency is long enoughcally 2 seconds) to cause a hard handoff. The time to cover all frequencies is short enoug12 seconds for 2 to 6 frequencies) to cause mobiles traveling across the hard handoff bounhandoff before the mobiles are impaired. Idle mode handoff requires a sync channel for J-008. Idle mode handoff requires both sync and page channel for IS-95A and Japan-CDMA.and page information does not change as the pilot beacon hops frequences. Active calls dosync or page channels.

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er fre-lizedber of

Table on Contents• Introduction

• Theory

• Lab Test

• Field Test

• Where it does not apply

• Conclusion

• Appendix A:Hard Handoff explaination

• Appendix B:Initial Concerns

Introduction:

• Currently all hard handoffs in CDMA are caused by pilot beacons. Pilot beacons arecally 10 dB lower than pilots. As the mobile travels into the coverage area of the new cell wpilot beacon, the beacon will, at some point, get stronger than the pilot from the old cell. Thgers a hard handoff to a new frequency. Please refer to Appendix A for more detaileds onbeacon theory.

• Today, each frequency in the old cell requires a corresponding pilot beacon. Three Cfrequencies in the old cell would require three pilot beacons in the new cell. However, the necan have one, three, or any number of CDMA frequencies.

• Frequency Hopping Pilot Beacon reduces costs by replacing multiple pilot beacon ement in each sector of a BTS with one peice of pilot beacon equipment. The single TX pilot bis scanned amoung the old frequecies.

• The purpose of this document is to outline the plan to show proof of concept for scapilot beacons. Theory, Lab Test, Field Test, and where it does not apply. A lot of informapresented in this paper applies to all pilot beacons independent of whether they are frequenping or not. Appendex A covers the general Pilot Beacon theory. Appendex B has initial conabout frequency hopping pilot beacons

• This paperõs idealized examples use 3 hopping frequencies, 2 seconds dwell time pquency, 4 dB Tcomp and 0.2 watt pilot beacon power. The concepts shown by these ideaexamples can be easily transfered to real world CDMA systems that may have different numfrequences, dwell time, Tcomp, or pilot beacon power.

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General Hopping Beacon Theory

• The three figures on the previous page represent the generalize case for frequency hpilot beacon.

• Figure 1 shows that pilot beacon does not imply that only pilot is transmitted. Sync page channels are also used except for J-STD-008 where only page channel is not neededbeacons are set 10 dB lower (0.2 watts) than that typical pilot (2 watts) in a system. The lobeacon power insures that when a mobile hard handoffs to the new frequency, that it is closcell and well withing the cell range on the new frequency.

• Figure 1 implies that the only thing that changes over time is the frequency switch. Itbetween Freq 1, Freq 2, Freq 3, Freq 1, etc. Note how there is no change in the pilot, sync, channels. However, the hopping beacon must use the same PN for all 3 frequencies. This awas chosen to simplify the software and hardward need for pilot beacon. Changing TX frequkeying and dekeying the LPA can easily be isolated to the BBX software. No CBSC softwmodification is needed to change sync and page information as the beacon hops in freque

• Hard handoff during an active call is illustrated in Figure 2. A mobile has a call on FrFreq 2, or Freq 3 in an old cell. As a mobile travels to a new cell with a beacon, the beacon (B1, Beacon 2 or Beacon 3 respectfully will get to point where it is 4 dB stronger than the old At that point, after receiving a Tcomp PSMM (Pilot Strengh Measurement Message) from thbile, the CBSC will direct the mobile to hard handoff to Freq 4, Freq 5 or Freq 6 respectfullythe new cell. No sync or page information is used for the handoff.

• Idle mode hard handoff is much different as shown in Figure 3. A true MAHO with nCBSC involvment, the mobile monitors pilot and sync and maybe page to make its own hardoff decision. A mobile monitoring Freq 1, Freq 2, or Freq 3 in an old cell. The exact frequendetermined by a hashing algorithm. As a mobile travels to a new cell with a beacon, the be(Beacon 1, Beacon 2 or Beacon 3 respectfully will get to point where it is stronger than the ol. At that point, the mobile read the beacon sync channel. In J-STD-008, the CDMA_FREQrameter in the sync message will cause the mobile to start to monitor Freq 4. For other CDstandards, the mobile must continue on to the paging channel to receive a CDMA Channelmessage to cause the change to Freq 4. A new hashing algorithm on the new cell will thenthe mobile to monitor Freq 4, Freq 5 or Freq 6.

•

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does directs directmobileothessage

callandoffit goes

• Figures 4, 4 & 6 illustrate the slight differences between the standards. J-STD-008 not require a page channel. The CDMA_FREQ information at the end of the sync messagemobiles to the new frequency. IS-95A uses the CDMA Channel List on the page channel tomobiles to the new frequency. The Global Service Redirest Message, which can also direct to new frequencys, is not currently available in Motorola CDMA systems. We know that bsysc and page are need for Japan CDMA. However, we have deturmined the exact page mused.

• Figure 7 shows an older implimentation of pilot beacon with no sync or page. Activehard handoff works fine, since it does not use sync or page. However, mobile idle mode hhad some out of service time. When a mobile receives a strong pilot beacon with no sync,

Use Worview Ma

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tect a
to its primary frequency. If the primary frequency was Freq 1, the mobile will then again destrong pilot beacon with no sync. The mobile repeats this cycle 50 to 100 times.
Hard Handoff Flows

Active Call

1. Strongest Pilot in Old Cell2. Pilot Beacon in Neighbor List3. Pilot Beacon > Tadd

Mobile issues PSMMCBSC denies Soft Handoff to New PilotMobile may repeat step 3 several times

4. Pilot Beacon > TcompMobile issues PSMMCBSC issues Hard Handoff for mobile to New Frequency

Idle Mode J-STD-008

1. Strongest Pilot in Old Cell2. Pilot Beacon in Neighbor List3. Pilot Beacon > Old Pilot4. Mobile receives Beacon Sync Message

CDMA_FREQ field in sync causes Mobile to change to New Frequency5. Mobile receives new sync and page6. CDMA Channel List message in page causes Mobile to hash to its

appropriate Frequency.

Idle Mode IS-95A

1. Strongest Pilot in Old Cell2. Pilot Beacon in Neighbor List3. Pilot Beacon > Old Pilot4. Mobile receives Beacon Sync Message5. Mobile moves to Beacon Page Channel

CDMA Channel List message in page causes Mobile to changeto New Frequency.

6. Mobile receives new sync and page7. CDMA Channel List message in page causes Mobile to hash to its

appropriate Frequency.

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lete a

nd this

t

Frequency Hop Timming

* Typical Sync cycle is less than 240 mS. Give two cycles for the mobile to lock and compcomplete cycles.

* Typical paging channel decode time is also estimated to be around 240 mS at 4800 BPS aassumes that there are no personal station directed messages.

* The paging channel is there to deliver theSystem Parameter Message, CDMA Channel LisMessage, and most importantly , the Global Service Redirection Message.

* Call processing dictates that, if theGlobal Service Redirection Message is sent, it shall be sentonce every 1.28 Seconds (the T1b time period). *

• Idle Slotted Mode (1.28 or less timing)

• Origination (Originate, then get bommed) low prob event.

• Phone Power Up

Lab Test

• Soft Handoff if HH not available.

• handoff is one shot deal. HH. vary on time

• Call, idle

Use Word 6.0c orview Macintosh p

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the

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er list)lwaysr coin-pilot

e Can-ndoff is

Field Test

• Before and After data.

• 4 phones, 2 people van, 1 person land line.

• Drive one direction. Find handoff point. All tries except drops when mobile reaches point. (100 drive bys @ 10 per hour = 10 hours of testing.)10 hour before data, 10 hour after data.

• Put programable atten on beacon. Adjust duty cycle to match. 2 seconds on, 10 soff. Call Drops out of 100 calls. Idle mode, no valid system out of 100 tries. Call Terminatioof 100 calls. (with slotted if available) Call origination 100 calls. Call origination 100 calls.

Where does not apply

• Not test extreem situation. Over a hill the signal disappears rapidly.2% of situations will not work. Require more pilot beacons.

• Rapid Change of pilots

• Cresting a hill

• Extreme shadowing

•

•

Categories of Personal Station Service States

1. Mobiles in the ACTIVE mode, engaged in a call.

These mobiles are constantly searching the neighbor list (and more infrequently the remaindlooking for neighbor cells and sectors for soft or softer hand-off. The Beacon pilot should abe configured in adjacent cell neighbor lists. When a mobile search of the beacon neighbocides with the multiplexed transmission on the mobile frequency, the mobile will detect the and take asses the signal strength.

If the signal strength is above the absolute T_ADD threshold, the mobile adds the pilot to thdidate Set and sends up a Pilot Strength Measurement Message to the base. This soft hadenied by the CBSC since it knows the beacon pilot does not support soft handoff.

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e Can-e triggersging

Wheng chan-d of

en the

5A mo-el

ing on

therches This is not

goingbackpilotegion

sync

If the signal strength is above the relative T_COMP threshold, the mobile adds the pilot to thdidate Set and sends up a Pilot Strength Measurement Message to the base. This messagthe base to perform a hard hand-off. The hard hand-off is performed and the Sync and Pachannels are never decoded.

2. Mobiles in the IDLE mode, constantly monitoring the paging channel.

These mobiles are constantly looking for neighbors also to perform an Idle mode hand-off. an Idle mode mobile hands off to a pilot beacon, it proceeds to decode the Sync and Paginnels. If it is a PCS JS-STD-008 mobile, it will detect the CDMA_FREQ parameter at the enthe Sync message and change to that frequency instantly.

If it is a IS-95A mobile, it will decode sync and proceed to decode the paging channel. Whmobile reads the Global Service Redirection Message it performs an hard hand-off the specifiedfrequency. (Note: it has been proposed that the paging channel could be eliminated for IS-9biles by setting the sync channel MIN_P_REV {minimum protocol revision} level to one levabove all mobiles in service.)

3. Mobiles in entering the System Determination Substate, recovering from a fade or powerwithin range of the beacon.

These mobiles come up into the IDLE mode first, so all of the above apply to them also. Ifmobile comes up during the period when the carrier is multiplexed off, then the mobile seafor the secondary or tertiary CDMA carriers (or the AMPS signaling channel) automatically. is exactly what would happen if the mobile came up in a region just beyond the beacon, anda problem.

Placing Sync and Paging on the beacon avoids the problem of the mobile chasing its tail byto the primary CDMA frequency, detecting a pilot, attempting sync detection, failing, going to system determination, being reassigned to the primary CDMA frequency, searching for etc. A process which can disrupt service for typically 15 to 20 seconds, until the beacon ris crossed or the mobile gives up and tries another frequency.

Note, multiplexing a pilot only signal quickly, at a low duty cycle, may element the need for and paging altogether.

•

•

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Theell 1,

e callell 2 dB.

U v in

Appendix A:Pilot Beacon Theroy

Hard handoff from one CDMA frequency to another is illustrated in Figure 1. above. Cell 1, F1 (Frequency 1) pilot power and the Cell 2, F2 pilot power are 2 watts each. The CF2 pilot beacon and theCell 2, F1 pilot beacon are 0.2 watts each.

Assume a mobile starts a call at Cell 1 and travels to Cell 2. The mobile initiates thon F1. The MHO (mobile assisted handoff) algorithm will keep the mobile on F1 until the Cpilot beacon on F1 is received 4 dB higher at the mobile than the Cell 1 pilot on F1. The 4higher condition, which occurs at Point A, causes the mobile to hard handoff from F1 to F2

A mobile traveling from Cell 2 to Cell 1 will hard handoff atPoint B.

se Wordiew Mac

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icess place

nd oneng 60econdsrd hand-

whenne willan 2acone hard

U 6v n

Figure 2 shows a scanning pilot beacon in a 6 frequency CDMA system. Cell 1 servcalls using odd frequencies. Cell 2 services calls using even frequencies. Hard handoff takefrom odd and even frequencies and vice versa. (F1<--> F2, F3<-->F4, F5<-->F6)

Assume a van, at Cell 1, starts 3 calls on 3 phones, one call on F1, one call on F3, acall on F5. The van travels to Cell 2. Cell 1 and Cell 2 are 1 mile apart. The van is travelimph. Also, assume the Cell 2 pilot beacon is scanned between F1, F3 and F5, dwelling 2 son each frequency. Finally, assume a phone can lock onto a scanning pilot beacon and haoff in less than 2 seconds.

The van arrives at the Cell 1 & Cell 2 hard handoff boundary, at t=0 seconds, exactly the Cell 2 scanning pilot beacon starts to TX on F1. Less than 2 seconds latter, the F1 phohard handoff to F2. At t=2 seconds, the scanning pilot beacon starts to TX on F3. Less thseconds latter, the F3 phone will hard handoff to F4. At t=4 seconds, the scanning pilot bestarts to TX on F5. Less than 2 seconds latter, the F5 phone will hard handoff to F6. All thhandoffs occurred within 6 seconds, or 0.1 miles of the hard handoff boundary.

se Wordiew Maci

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omese origh ca-

ower to ini-ations

ntownectors.r all 8

mple 6f. Po-

hereead ofis need-

ginged Mes-

terthodsall bea-

ainssible.

•

•

• Attachment for Part 2: (State the problem(s) solved by the invention)

• The Pilot Beacon approach to managing hard handoff in a CDMA cellular system becvery costly in systems with more than three or four carriers. Lower capacity sites, with ontwo carriers must deploy a pilot beacon on every carrier sector supported by an adjacent hpacity with many more carriers.

• When handing down from a high capacity site, with more carriers than an adjoining lcapacity site, mobile units must soft handoff on the intersecting carriers or receive a beacontiate a hard handoff on the carriers not covered at the lower capacity site. Various configurrequire many pilot beacons.

• For example, a JCDMA system has 10 carriers deployed in 6 sectors per site in a dowurban area. A site along a highway out of town or in a subway tunnel deploys 2 carriers in 3 sEven though the low capacity site has only 6 carrier sectors, it must provide pilot beacons foother carriers, on each of the 3 sectors. Total beacons required = 24. In this example a sicarrier-sector site needs to broadcast another 24 pilot beacons just to support hard handoftentially a costly problem.

• The deployment of pilot beacons will vary widely from site to site depending upon wthe hard handoff boundaries are. It is not desirable to burden every cell site with the overhpilot beacon hardware for the sake of the few sites that need it. A simple modular approach ed.

•

• Beacon provides a Sync channel for the primary CDMA_FREQ parameter and a pachannel for the Global System Redirection Message. There are no Personal Station Directsages on the Paging Channel.

• Attachment for Part 5: (Improvements over known technology)

• Primary improvement: Integration of multiple pilot beacon carriers into one transmitsignificantly reduces device cost, size, and complexity. Issues with antenna combining meare reduced. No longer are multiple turned cavity power combiners necessary to combine con carriers prior to connection to an antenna.

• The optimal trade-off between multiplexing channel gain and system performance remto be determined, but it is conceivable that from 3 to 1 up to 6 to 1 multiplexing may be fea

Appendex B:Scanning Beacon Initial Concerns

1. Scanning pilot would increase the handover detection time.

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oc-

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lar ve-hicle

allto cap- the

f con-ld do.es. It work,

be on

t dif-

r spe-sts,

This will increase dropped call rates.Joe Pettinger

2. When the scanning pilot comes up on a carrier, bursts of handoff on that carrier willcure. Joe Pettinger

3. Will mobiles get confused and not be able to receive pages because it's constantly lunlocking on a time shared pilot?Joe Pettinger

4. We've always assumed that QC has tweaked their chipset and SW for some particuhicle speed. How could you build a matched filter for a fading process without knowing the vespeed? Answer: You don't. You just try to build something that does a "reasonable" job at speeds. Coupled with this is some sampling scheme that is simultaneously "slow enough" ture decorrelated data while "fast enough" not to miss interesting portions of the signal. It'ssampling that has me worried.Barry Menich

5. I think the best thing we could do would be to actually test scanning under a variety oditions with QC, Motorola, Oki, Samsung, LG, and Nokia mobiles and see what they all wouSince, unlike GSM, none of this is in the spec., I can only warn against undesirable outcomwould be unfortunate to design a hopping beacon and then find out that Nokia mobiles won'tetc.

Barry Menich

6. Slotted mode and idle handoff muddy the waters as to exactly when sectors need toor off. Barry Menich

7. Different pilot Ec/Io filters implemented by different subscriber manufacturers make ificult to speculate on a minimum energy requirement.

Barry Menich

8. The baseband portion of the hopping generator would need to be cognizant of sectocific information needed on the sync/paging channel (Global Service Redirect, Neighbor Lietc.). Barry Menich

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7.2 N-Way SHO and Complex SHO (Barry’s paper or parts thereof

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of 182

11/25/97


TO: Neal Campbell, Pat Connors

FROM: Barry J. Menich, Chris Schmidt, & Dennis Thompson

RE: Partial N-way, Minimal Complex Handoff AlgorithmStrawman/Proposal

CC: Jim Aldrich, Anil Barot, Will Bayer, Matt Dillon, Marilyn Escue,Steve Dubberstein,Ken Fujikawa, Roland Ho, John Kay, Randy Kohl, Gerry Labedz, Bob Love, JohnNolting, Devesh Patel, Joseph Pedziwiatr, Joseph Pettinger, Tom Ritchie, GinoScribano, Paul Steinberg, Keith Ten Brook,John Thode, John Voigt, Dan Willey

This memo will serve as a “strawman” proposal for our next round of softhandoff upgrades which is centered around the “Partial N-Way SHO” algo-rithm. We are soliciting feedback from the technical community regardingthe necessity for this feature as well as the algorithms that comprise thefeature. Please forward your comments to Barry Menich, Chris Schmidt, orKen Fujikawa.

Two algorithms will be discussed. One algorithm is a very simple extensionof today’s normal soft handoff algorithm with Fast Pilot Shuffling. The otheralgorithm is more complicated and strives to minimize PN “thrashing” aswell as limiting pilot shuffling “exposure” during periods of poor RF or non-dominant PN.

Per our previous discussions, it is assumed we are still targeting R8 as therelease for introduction. More specifically, this memo will contain proposalsfor sub-algorithms known as “Cell Swapping1”, “Soft Shuffling”, and “SofterShuffling”. Obviously, simulation results of any algorithms propsed hereinare desirable prior to full committment to a particular release. However, thisdocument represents a “best shot guesstimation” of an N-Way SHO algo-rithm. Note that the complexity of the algorithms derives partly from thelack of HW available to support true 6-Way SHO.

Definitions:Provided below are some definitions that we’ve adopted for the sake of thisdocument and to further facilitate internal discussion. Note that there areno industry standards with regard to these. Thus, they should not be usedoutside Motorola until such time that we are confident in the need for thesefeatures and/or their implementation in a particular software release.

HHO. Hard HandOff.

SHO. Soft HandOff.

1. This algorithm will probably replace the current “Fast Pilot Shuffling” feature.

PAGE 183 OF 208


s.

c.

Full Complex : This feature implies the ability (on the part of the infrastructure) to per-form multiple add and/or drop operations within one Extended Handoff Direction Mes-sage. Because of the desire, at the time of Extended Handoff Direction Messagetransmission to utilize the maximum number of currently available forward and reverselinks for the procedure transaction, this also implies 2N forward/reverse links where N isthe maximum expected size of the active set.

Partial Complex : This feature implies those complex operations that may be accom-plished by utilizing existing XCDR hardware. These operations are defined by the JimAldrich matrix and constrained by the number of forward and reverse links required tocomplete any given handoff operation1.

HHO Complex : Also known as “complex HHO”, this feature implies the ability on the partof both subscriber unit and infrastructure to connect the subscriber unit into at least 3-way soft/softer handoff immediately at the target following an Extended Handoff DirectionMessage. Thus, N forward links are transmitting as the subscriber unit performs connec-tion procedures at the target.

Full N-Way : This feature implies XC hardware able to support 6 forward and 6 reverselinks. Uses “Next Generation” or “improved” XCDR circuitry that supports the ability tomanage 6 MCCce’s.

Partial N-Way : This feature implies the ability to support up to 6 forward (Walsh codes)and 3 reverse links2. Uses currently available XCDR circuitry. Forward links are a mix ofsoft and softer connections such that we are always constrained to 3 reverse links.

Full Diversity N-Way : This feature implies everything contained with “Full N-Way” aswell as subscriber unit hardware with N demodulation elements.

Mobile Assisted Pilot Dominance : This feature refers to the recent Qualcomm pro-posal of using a secondary threshold that is a function of the sum of the active set SNRsas a technique to inhibit Pilot Strength Measurement Messages. See appendix #B forclarification of the Qualcomm proposal.

Infrastructure Assisted Pilot Dominance : This feature implies a handoff algorithm onthe part of the infrastructure that examines active set and candidate set pilot Ec/Io esti-mates in the Pilot Strength Measurement Message and attempts to determine an optimalactive set while simultaneously minimizing the number of forward link transmitters to theminimum required for quality forward link reception.

Cell Swapping : An algorithm in the infrastructure that works with Partial N-Way SHOand actually performs reverse link handoff (switching an XC connection) from one cell

1. As an example, consider the situation where a subscriber unit is in 3-way SHO between 3 different BTSIf we wanted to simultaneously add a new BTS while dropping one of the existing BTSs, we’d still want totransmit theHandoff Direction Message via the transmitters of the 3 existing BTSs and receive theHandoffCompletion Message via the receivers of the 3 new BTSs. Due to current downlink combining techniques,we can’t just decide to drop a transmitter from the active set without first informing the subscriber unit, et2. If the combining bit in theExtended Handoff Direction Message is used, then the mobile only responds to3 sets of PCG puncture bits.

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heicee the

ive set

ill

le havewhere

a

,

metors

(BTS) to another. It is an operation similar to Fast Pilot Shuffling, however performed atthe BTS, rather than PN, level.

Soft Shuffling . A technique used with Partial N-Way SHO whereby a pilot at one BTS isswapped out in favor of another, superior performing, pilot at another BTS. Both BTSscurrently serve the subscriber unit.

Softer Shuffling . A technique used with Partial N-Way SHO whereby a pilot at one BTSis swapped out in favor of another, superior performing, pilot at the same BTS.

Fast Pilot Shuffling . Also known as “FPS”, a technique used in R5, R6, and R7 wherebyT_TDROP timers for active set pilots are preempted only in three way SHO when in thepresense of a candidate set pilot that meets the shuffle criteria. Fast Pilot Shuffling doesnot discriminate between soft and softer connections.

Non-Dominant PN . This is a condition defined by good/excellent RF coverage (non-ther-mal noise limited case, >-80 dBm) with poor pilot Ec/Io performance. Also described bysome in the industry as “pilot pollution”.

Algorithm Requir ements / Wish ListN-Way soft handoff will require modifications to the MM to determine when to “CellSwap”. Because of the current software limitation of 3 forward/reverse link pairs, the FastPilot Shuffling algorithm does not discriminate between pilots that originate from thesame or different sites. Thus, FPS will no longer be useful. Instead, FPS concepts needto be extended to “Cell Swapping”.• Minimize the number of “Cell Swaps”. As with FPS, Cell Swapping is an undesirable additional burden on t

infrastructure as well as an additional handoff operation, with all it’s attendant messaging (and resulting vodegradation due to lost speech content), to the end user. In addition, Cell Swaps have the potential to leavsubscriber unit especially vulnerable on the forward link during swap transitions.

• Give the customer/system optimizer some control over “Cell Swaps”. The current FPS algorithm triggers off aT_COMP event as well as an event defined by the candidate set pilot Ec/Io being stronger than 2 of 3 actpilot Ec/Io’s. This latter trigger is not directly1 under the control of the optimizer/operator. Should this becomeknown to the operators (right now this is not generally known - even within Motorola), it could be provoke feelings.

• Suppress Cell Swapping under poor pilot conditions or conditions of non-dominant PN. One negative attributeof the current FPS algorithm is that it is completely insensitive to absolute pilot Ec/Io values. Several peopcome forth to complain about the algorithms performance in poor RF and/or non-dominant PN conditions dropping down to 2 forward links (during the shuffle operation) is detrimental to the health of the call.

• Concurrent drop of multiple softer links. This is desirable to minimize the amount of “exposure time” while inmarginal forward link diversity state due to the lack of Full Complex capability2.

• Full N-Way Softer Capability. Japan 6-sector will eventually be implemented with single BTS cellsites. Thuspossibility exists for 3-way, 4-way, and possibly more, softer handoff.

1. Use of increasing values of T_ADD can be used to “weed out” the candidate set and thereby inhibit sonumber of FPS operations. Unfortunately, this requires more skill than most operators and system operapossess.2. Chris believes that this is possible.

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y

-

inpment

as-

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better

active

criber

n otherter, etc.

-

s

• Provide at least some Pilot Dominance capability.It should be noted that the release date for an N-Way SHOalgorithm is sufficiently far enough into the future to warrant consideration of impact with respect to heavilloaded CDMA systems1.

• Provide growth path for the eventuality of Full Complex, Full N-Way, and a full implementation of Infrastructure Assisted Pilot Dominance algorithm(s). The R8 implementation should not inhibit, or restrict, future softhandoff algorithm evolution.

• Factor in consideration for IS-95/J-STD-008 Pilot Strength Measurement Message transmission rules. Bothspecifications have clear rules for transmission ofPilot Strength Measurement Messages. This rules must beadhered to.

• The implementation must be “achievable” by R8. This implies that the algorithm eventually selected lies withthe capabilities of current hardware configurations (including inter-CBSC soft handoff) and software develoavailability (ie. not so complex that it cannot be completed within a release cycle).

• Provide “Fall-back” position in case of possible dissatisfaction with Qualcomm demodulator assignment/resignment algorithm(s). This one’s gonna be tough2.

General Attrib utes of “Partial N-Way”Partial N-Way soft handoff has the following attributes:

1.) General ADD/DROP Operations Preserved: Usage of T_ADD, T_DROP, T_COMP, and T_TDROP parais preserved.

2.) Cell Swapping: Swap connections from one cell to one, or more, connections at another cell.

3.) Softer Shuffling: Fast Pilot Shuffling amongst pilots eminating from a single BTS.

4.) Soft Shuffling: Fast Pilot Shuffling amongst pilots eminating from two different BTSs.

5.) Softer Active Set Limiting: Limitation of the number of subscriber active set members by BTS (needdescription here.

6.) Multiple Softer ADD Operation: Adding more than 1 co-BTS pilot (softer connection) to the subscriber set.

7.) Multiple Softer DROP Operation: Dropping more than 1 co-BTS pilot (softer connection) from the subsactive set.

8.) Maximum number of softer handoff legs from any site is self-limited 3-sector or 6-sector deployments. Iwords, we would never implement a 6-sector site with MCCx8 HW and expect it to be capable of 4-Way sofAll 6-sector sites to be implemented by MCCx24 HW.

Cell Swapping Under “Partial N-Way”Consider Figure #1 below where a subscriber unit is in 5-way soft handoff with cells A,B, and C. In this figure, solid lines are indicative of forward link connections from thecell(s) in question. Thus, the subscriber unit is in 2-way softer handoff with cell A, 2-way

1. As an example, consider the current subscriber growth rate for Hong Kong extrapolated to the R8 timeframe.2. Motorola has no experience with Qualcomm subscriber unit performance under N-Way SHO conditionbeyond N=3.

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softer handoff with cell C, and 1-way soft handoff with cell B. The dotted line eminatingfrom cell D and terminating at the subscriber unit denotes that one sector from cell D hasachieved candidate set status from the subscriber unit’s perspective.

Figure #27. 5-Way Soft Handoff via Partial N-Way

For the purposes of our discussion, we shall assume that the soft handoff algorithm inthe MM has decided that cell D’s pilot will provide better forward link performance for thesubscriber unit than the composite forward link signals from cell A. This trigger is called a“cell swap”, and the intermediate step is shown in Figure #2 along with the final result inFigure #3. Notice in Figure #2 that all forward links from Cell A have been dropped simul-taneously.

Notice the simularity between “Cell Swapping” and the current FPS algorithm. FPS doesnot discriminate between soft and softer connections. Cell Swapping will need to havethis capability.

Figure #28. Intermediate Stage of “Cell Swap” Procedure

Cell A

Cell B

Cell C

Cell D

Mobile

Cell A

Cell B

Cell C

Cell D

Mobile

All forward linksassociated withCell A have beendisconnected.

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Figure #29. Final Result of “Cell Swap” Procedure

The execution aspects of cell swapping are obvious. They are soft handoff “add” opera-tions that are identical to those currently performed. The soft handoff “drop” operation ofmultiple forward links is a small stretch from today’s single forward link drops.

Softer Shuffling Under “Partial N-Way”Consider Figure #4 below where a subscriber unit is in 5-way soft handoff with cells A,B,and C. In this figure, solid lines are indicative of forward link connections from the cell(s)in question. Dotted lines indicate transmission cells/sectors for candidate set pilots. Inthis illustration, pilots #1 and #2 are active set pilots while pilot #3 is a pilot that hasachieved an Ec/Io level sufficient to trigger a softer shuffle.


In Figure #5, the intermediate step of a softer shuffle is depicted with the MM having cho-sen pilot #1 as the pilot to be dropped from the active set. Note that pilot #1 and pilot #3are co-BTS pilots.

Cell A

Cell B

Cell C

Cell D

Mobile

Cell A

Cell B

Mobile Cell C

#1#2#3

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Figure #31. Intermediate Stage of Softer Shuffle Procedure

The procedure finally finished in Figure #6 which shows that pilot #3 has been “shuffled”into the subscriber unit active set. Note that the mechanism used was not “Full Com-plex”. Note also that Cell C was limited to 2 active set pilots only. This will be covered inthe section on “Pilot Dominance”.

Figure #32. Final Stage of Softer Shuffle Procedure

Soft Shuffling Under “Partial N-Way”Consider Figure #7 below where a subscriber unit is in 6-way soft handoff with cells A,B,and C. In this figure, solid lines are indicative of forward link connections from the cell(s)in question. Dotted lines indicate transmission cells/sectors for candidate set pilots. Inthis illustration, pilots #1 and #2 are active set pilots while pilot #3 is a pilot that hasachieved an Ec/Io level sufficient to trigger a soft shuffle. In this example, pilot #4 hasbeen chosen by the MM software as an underperforming pilot to be dropped from thesubscriber unit active set in favor of pilot #3.

Figures #8 and #9 depict intermediate and final stages of the soft shuffling operation.

Cell A

Cell B

Mobile Cell C

#1#2#3

Cell A

Cell B

Mobile Cell C

#1#2#3

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Figure #34. Intermediate Stage of Soft Shuffle Procedure

Figure #35. Final Stage of Soft Shuffle Procedure

Implications of N-Way SHO ImplementationThe CDMA Static Simulation (CSSS) may need to be ugraded. This upgrade work wouldtake into account the eventual partial N-Way algorithm chosen.

Cell A

Cell B

Mobile Cell C

#1#2#3

#4

Cell A

Cell B

Mobile Cell C

#1#2#3

Cell A

Cell B

Mobile Cell C

#1#2#3

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not

e.

red.

ich

Won’t have gains for 4, 5, and 6-way forward power control unless we specify. Not havinggains available will put us in a position of possibly delivering poorer capacity than wouldbe possible. Perhaps this is acceptable for 1, or 2, release cycles.

Algorithms

Proposed Simple RulesThe following proposed simple rules should always apply regardless of what algorithm isfinally chosen.

Rule #9.) The algorithms will follow the convention in Fast Pilot Shuffling whereby the XC and MM arerequired to have memory capability with regard to “add” pilots on any shuffle operations.

Rule #10.) Any T_COMP event for a candidate set pilot where the candidate’s Ec/Io in thePilot Strength Measure-ment Message is T_COMP dB greater thanall active set pilot Ec/Io, from any BTS, shall be honored1. This event willbe referred to as “T_COMP Prime” in this document and willalways invoke some response from the infrastructur

Rule #11.) Any T_DROP event in aPilot Strength Measurement Message will always result in at least one active setpilot drop. Add events in PSMM always prioritized over drop events, except in cases where shuffling is requi

Algorithm DetailThe basic philosophy taken with the proposed approach is to minimize the number of“highest risk” handoff operations. Beyond that, the algorithm is no more complicated thanmaking decisions of when to add candidate pilots and when to drop active pilots. Handoffoperation risk is proposed as Figure #10 below.

Figure #36. Handoff Risk Hierarchy

The current state of the call (which includes the number of active set pilots and theirassociated BTS identities) and the current contents of the Pilot Strength MeasurementMessage (active set and candidate set Ec/Io information and “keep” flags) defines thefuture state space per Simple Rule #1.

The primary algorithm we are proposing (Algorithm #1) assumes sorting of Ec/Io foractive set and candidate set pilots as well as the ability to associate both with BTSs. Thisstatement is a gross oversimplification of the algorithm/software actually required to real-

1. Honoring this simple rule gets us past J-STD-008 section 2.6.6.2.5.2 and IS-95A section 6.6.6.2.5.2 whspecifies rules for transmitting T_COMP event information to the infrastructure.

Cell SwapSoft ShuffleT_COMP PrimeSofter ShuffleDrop BTS (non-Cell Swap)T_ADD (single or multiple)T_DROP (single)In

crea

sing

R

isk

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ize such a capability. The pre-processing portions of the algorithm are shown in Figure#11 below as a process flow. Note that the entire flow need not be executed for allevents. For example, a simple single pilot drop event or a BTS with only one connectionneed not invoke any Ec/Io sorting or any BTS Associations.

Figure #37. Handoff Pre-processing Example

In terms of detection, Figure #10 can be expanded to yield the following criteria require-ments:• Single pilot drop.

• Single pilot add.

• Multiple pilot add (same BTS only).

• Multiple pilot drop (same BTS only).

• Softer Shuffle.

• Soft Shuffle.

• Cell Swap.

Finally, three algorithms are presented here. Algorithm #1 is extremely complicated.Algorithm #2 is insensitive to soft versus softer connections. Algorithm #3 requires someof the logic of Algorithm #1 but strives to minimize the active set via a form of “diversity”calculation utilizing the information in each Pilot Strength Measurement Message.

Algorithm #1Algorithm #1 is an intentionally complicated algorithm where a “superstructure” makesdecisions regarding add/drop/null events and then calls various sub-procedures (add,drop, swap). The “superstructure” and sub-procedures are presented separately toreduce visual complexity. Note the use of the “AddFlag”. If any “add” operations shouldfail to produce a result, then any existing “drop” events in the PSMM will be honored. Thismakes use of every opportunity to keep the active set “clean”. The algorithm alsoassumes that Table #1 allows four BTS connections. The algorithms have also not beenreduced to their minimal logical expressions and may contain flaws at this point.

One point needs to be made with regard to the handoff “add” operation. It is the philoso-phy of this document that new BTSs be added to a call instead of additional sectors atexisting servers in the case of multiple candidate pilots existing in a Pilot Strength Mea-surement Message. The idea here is that the macrodiversity benefit to the call might be

PSMM Event Discrimination

Ec/Io Sorting (Active Set)Ec/Io Sorting (Candidate Set)

BTS Associations with

HandoffDecision

Parallel Activity?

associated Handoff Events

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h

of more value than additional softer handoff legs due to high probability of decorrelatedshadowing between sites.

SuperStructure :Perform Event Discrimination

For (i=0; i<All Candidate Set Pilots; i++)If

Then

EndifEndforSort T_COMPPrimePilotSort and count Drop pilot(s)Sort and count candidate set pilot(s)

Sort and count T_COMP pilot(s)Sort and count Add pilot(s)

AddFlag = 0DropFlag = 0

Set

If (((Event == ADD) || (Event == T_COMP) || (Event == T_COMPPrime)) && (#BTS == 3))

IfThen CallCell Swap

ElseIf

If ((active_set_size == 6) && (Candidate BTS currently at Table#1_Constraint))Then CallSoft Shuffle

Else If ((active_set_size < 6) && (Candidate BTS currently at Table#1_Constraint))Call Softer Shuffle

Else CallAddEndif

EndifEndif

EndifIf (AddFlag = 0)

If (((Event == ADD) || (Event == T_COMP) || (Event == T_COMPPrime)) && (#BTS < 3))If (active_set_size < 6)

Then CallAddElse CallSoft Shuffle1

EndifEndif

EndifIf ((AddFlag == 0) && (DropFlag == 0) && (T_DROP Event))

Then CallDropEnd

1. This call should handle the situation of 2 BTSs with 3 forward links each. The other 2 BTS situation wit4 links and 2 links is not allowed given Table #1.

Candidate Ec/Ioi T_ADD>( )

CandidateScreenedi Candidatei=

#BTS Active BTSii 1=

N

∑=

Best Candidate Set Pilot Current Serving BTSs∉( )

Best Candidate Set Pilot Current Serving BTSs∈( )

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p

Drop : The following is an example of a simple “drop” event where single or multipleNoKeep1 pilots are involved. The precedence is to always try to drop an entire BTS worthof forward links, then all NoKeep pilots, and finally a single pilot. Unfortunately, it is thelatter case that will occur with the greatest frequency. Note that this loop causes no shuf-fling:If (#Drop Events in PSMM > 1)

Count NoKeep Pilots per BTSSort CountFind BTS with greatest countIf (All NoKeep Pilots In Same BTS)

If (Ec/Io of any NoKeep Pilot > Ec/Io of all Keep Act Pilot at same BTS)If (#BTS > 1)

Then DropALL pilots at BTSElse If (#BTS == 1)

If (# of Keep Act Pilots >= 1)Then Dropall NoKeep pilots at BTS

ElseDropweakest2 NoKeep pilot at BTS

EndifDropFlag = 1

EndifElse If (Ec/Io of any NoKeep Pilot ! > Ec/Io of all Keep Act Pilot at same BTS)

If (#BTS > 1)Then Dropall NoKeep pilots at BTS DropFlag = 1

EndifEndif

Else If (NoKeep Pilots Distributed Amongst Multiple BTSs)If (Ec/Io of any NoKeep Pilot > Ec/Io of all Keep Act Pilot at same BTS)

Then Dropall NoKeep pilots at BTSElse Dropweakest (by Ec/Io) NoKeep pilotEndifDropFlag = 1

EndifEndif

Else If ((#Drop Events in PSMM == 1) && (#Active_Pilots > 1))If (Ec/Io of any NoKeep Pilot > Ec/Io of any Keep Act Pilot at same BTS)

If (#BTS > 1)Then DropALL pilots at BTS

EndifElse

Droponly NoKeep pilotEndifDropFlag = 1

Endif

1. “NoKeep” pilots are active set pilots represented in the Pilot Strength Measurement Message with keeflag set to zero.2. This is obviously an unfortunate situation to find ourselves in.

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er

er

g

Add : The following is an example of a simple “add” event where single or multiple candi-date set pilots1 are involved. Note that this loop causes no shuffling. Also, the word “can-didate” is underlined everywhere to draw attention to singular and plural forms. In thecase of adding multiple forward links from a new BTS, all candidate pilot Ec/Io associatedwith that BTS must satisfy the composite2 T_ADD criteria in order to be added (i.e. aform of pilot dominance):Rank order pilot Ec/IoIf (#Candidates in PSMM > 1){

If (All Candidates in same BTS){If (BTS == OLD_BTS){

Then add allcandidates at OLD_BTS above composite T_ADD .AND. per Table#1_Constraint3 .AND.such that #Actives < 7.

AddFlag = 1Else If (BTS == NEW_BTS){

Then add all candidates at NEW_BTS above composite T_ADD .AND. pTable#1_Constraint4 .AND. such that #Actives < 7.

AddFlag = 1 Endif

EndifElse If (Candidates distributed over multiple BTSs){

If (BTS == NEW_BTS){Then add all candidates at NEW_BTS above composite T_ADD .AND. p

Table#1_Constraint5 .AND. such that #Actives < 7. AddFlag = 1

Else If (BTS == OLD_BTS){If (#Candidates < Table#1_Constraint6)

Then add strongestcandidate in PSMM.AddFlag = 1

EndifEndif

EndifElse If (#Candidates in PSMM == 1){

If (BTS == OLD_BTS){Then addcandidate per Table#1_Constraint7

AddFlag = 1Else If (BTS == NEW_BTS){

Else addcandidate AddFlag = 1

Endif

1. The probability of this occurring is probably higher than that of seeing multiple NoKeep pilots sincehandoff add operations might be deferred in favor of drops/swaps/T_COMP events.2. By this we mean the T_ADD value chosen by the MM algorithm that merges handoff parameters durinsoft handoff operations.3. Table constraint exception allowed under T_COMPPrime conditions.4. Table constraint exception allowed under T_COMPPrime conditions.5. Table constraint exception allowed under T_COMPPrime conditions.6. Table constraint exception allowed under T_COMPPrime conditions.7. Table constraint exception allowed under T_COMPPrime conditions.

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EndifEndif

Softer Shuffle : The following is an example of testing for the Softer Shuffling criteria andchoosing a pilot to drop.If (T_COMPPrime Event){

If (NoKeep pilots exist for this BTS)Then drop all NoKeep pilots at this BTS

Else drop weakest pilot associated with this BTS.Endif

Else

Calculate

If ( ) || (T_COMP Event)){

If (NoKeep pilots exist for this BTS)Then drop all NoKeep pilots at this BTS

Else drop weakest pilot associated with this BTS.Endif

EndifEndif

Soft Shuffle : The following is an example of testing for the Soft Shuffling criteria andchoosing a pilot to drop.If (T_COMP Event on OLD_BTS){

Find weakest pilot on other 2 BTSs.If (NoKeep pilots exist for this BTS)

Then drop all NoKeep pilots at this BTSElse drop weakest pilot associated with this BTS.Endif

Else If (T_ADD Event on OLD_BTS){

Calculate for other 2 BTSs.

Sort to find

If {

If (NoKeep pilots exist at )

Then drop all NoKeep pilots at

Else drop weakest pilot associated with .

EndifEndif

Endif

Cell Swap : The following is an example of testing for the Cell Swap criteria and choosinga BTS to drop.

Calculate for all legs of all 3current BTSs.

σBTS Ec/Ioii 1=

N

∑=

Candidate Ec/Io σBTS>( )

σBTS Ec/Ioii 1=

N

∑=

σWeakest BTS

Candidate Ec/Io σWeakest BTS>( )

σWeakest BTS

σWeakest BTS

σWeakest BTS

σBTS Ec/Ioii 1=

N

∑=

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Calculate for all candidate set pilots at new BTSs1

Rank order

Set from all

Rank order

Set from all

If (T_COMPPrime Event){

Drop all pilots at

DropFlag = 1Else If (T_ADD Event or Other T_COMP Event){

If {

Drop all pilots at

DropFlag = 1Endif

Endif

Non-Dominant PN or “Poor Coverage” : An algorithm extension to those shown abovewould suppress softer shuffling, soft shuffling, or cell swapping under conditions of non-dominant PN. The justification for this is that the shuffling/swapping procedures “expose”the subscriber unit to unnecessary risk on the forward link as the number of available for-ward links goes from N to (N-M) during the “drop” portion of the shuffle/swap. This ismore “true” in the cell swap case as cell swapping has the possibility of dropping severalforward links in one simultaneous procedure. One could argue that soft and softer shufflehave less inherent risk than a cell swap.

A simple technique to limit cell swapping under conditions of non-dominant PN would beto alter the trigger criteria (shown above) to eliminate T_ADD and T_COMP events.Thus, the algorithm would only trigger on T_COMPPrime events and honor Simple Rule#2. The disadvantage here is probably just a small capacity hit from having non-optimalBTS connections (due to the lack of the T_ADD and T_COMP triggers) in areas of domi-nant PN.

Another simple technique to limit cell swapping under conditions of non-dominant PNwould be to alter the values depicted in Appendix A to make cell swapping more difficultas a function of decreasing . The problem here is in deciding on a scaling factor. Theproblem is further compounded by noting that the algorithm will probably need to existduring an epoch when subscriber manufacturers go from the QC ASIC to proprietarydesigns that possibly support more than 3 demodulators. This has the effect of making itdifficult to decide on appropriate values of to use as forward link sensitivity is greatlyaffected by the diversity available2.

1. This should handle the situation where a call is already engaged with 3 BTSs and candidate set pilotsappear for more than one new BTS.2. In fact, we don’t even have forward link FER data available for anything beyond 3 demodulators.

σCand Ec/IoCandi 1=

N

∑=

σCand

σStrongest Cand BTS σCand

σBTS

σWeakest BTS σBTS

σWeakest BTS

σStrongest Cand BTS σWeakest BTS>( )

σWeakest BTS

σBTS

σBTS

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not

No

powerhis

hannel

n the some

Algorithm #2Algorithm #2 is much simpler than algorithm #1 in that it is insensitive to issues of softshuffling, softer shuffling, cell swapping, or non-dominant PN. The algorithm merelyexamines each Pilot Strength Measurement Message received and makes add/dropdecisions based on the contents. There is also no concurrent add/drop of softer links. Alimit is placed such that only 3 BTS are used no matter how many forward links are inSHO (just as in Algorithm #1). Fast Pilot Shuffling works in the same fashion as it doestoday, with the only modification being that it triggers with 6 forward links instead of 3 for-ward links and triggers with 3 BTSs in the presence of a 4th BTS candidate.

The advantage of Algorithm #2 is pure reduction in development effort making an R8 tar-get date more “achievable”. There is certainly much smaller development associated witherror legs in this case. The disadvantage of Algorithm #2 is lack of handoff suppressionfeatures (particularly cell swapping). It might be that the only way to achieve algorithm #1would be to code algorithm #2 into release R8 and then “evolve” it into algorithm #1 inrelease R9.

Algorithm #3The suggestion has been made that the table in Appendix A be used to calculate a “com-bined” Ec/Io value for the contents of every Pilot Strength Measurement Message usingboth active and candidate set pilots and then using this value in a comparison functionwith a target threshold. The algorithm would strive to add those candidates that assist inachieving the threshold and dropping those active set pilots that do not. The goal of suchan algorithm is simplification wrt to Algorithm #1. Several points can be made:• An algorithm of this type would possibly end up being insensitive to soft vs. softer connections and would

favor the adding of softer legs over cell swapping as Algorithm #1 does.

• Some form of cell swapping (and decision criteria) would still be required.

• Choosing the target combined Ec/Io would be a subject of debate. Witness the variety Ec/Io and TCH Eb/required to reach 1% FER as a function of vehicle speed, delay spread, etc.

• Choosing the target combined Ec/Io makes the algorithm insensitive to TCH Eb/No. Note that our forwardcontrol algorithm changes gain as a function of the number of forward TCHs involved in the soft handoff. Twould require a combined Ec/Io threshold that is a function of soft handoff.

• Choosing the target combined Ec/Io would be further complicated by differences in RS1 and RS2 forward cperformance. This might become especially vexing in a mixed vocoder system.

• As with Pilot Dominance, optimization choice is taken away from the field technician and instead, vested ialgorithm. While this is prudent approach the vast majority of the time, we will probably be presented withnumber of situations where a number of handoff “knobs” will be useful.

Algorithm Summary (Algorithm #1 Specific)As you can see, there’s a need for “add detection” and “drop target” algorithms at theMM. This is merely an extension of algorithms implemented today with FPS. In otherwords, you need to be able to detect a condition that would cause a shuffle or swap andthen decide on which pilot(s) to add. Since cell swapping is now the dominant feature

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e the

e exists

ble

value.

lute

that will put us at a disadvantage on the forward link (no availability of full N-way or fullcomplex), we make the following observations:• Ec/Io values contained with Pilot Strength Measurement Messages are transient values present at the tim

message was sent. Care must be taken to develop confidence in these values as swap/shuffle triggers.

• Choice(s) of drop cells/pilots needs to be made with high confidence.

• Choice(s) of add cells/pilots needs to be made with high confidence. By this we mean that high confidencthat the cell(s) to be added will out-perform the cell(s) dropped.

• A mechanism needs to be implemented to ensure that a PSMM containing “add” information will be availaupon termination of the “drop” portion of any swap/shuffle operation.

What is not so obvious is the criteria for cell swap detection or pilot shuffling. Many havemade the observation wrt the FPS feature that we tend to perform an excessive numberof handoff operations, more so than is necessary to support the call. This is probably afunction of the secondary criteria for pilot shuffling that the candidate set pilot have stron-ger Ec/Io than 2 out of 3 active set pilots. For Cell Swapping, we intend to put in place amore rigorous criteria and attempt to reduce the amount of falsing associated with shuf-fling/swapping. Appendix A shows a an Ec/Io Conversion look-up table composed ofintegers that correspond to the Ec/Io values contained in a Pilot Strength MeasurementMessage.The purpose of this table is to provide an integer-based means for dealing withEc/Io values without having to implement floating-point arithmetic (costly). There is alsosome execution time savings in using a look-up table technique.

The table in Appendix A is used as input to the Cell Swapping algorithm.• Each active set pilot Ec/Io in the Handoff Request Message is used to lookup the corresponding absolute

• Each candidate set pilot Ec/Io in the Handoff Request Message is used to lookup the corresponding absovalue.

It should be noted that, with the inclusion of mechanisms to perform multiple simulta-neous softer adds and softer drops, that the Cell Swapping is really no worse than thecurrent FPS algorithm while providing the benefits of more than 3 forward links.

Nature of Ec/Io Values in Pilot Strength Measurement MessagesThe Ec/Io measurement made by the subscriber unit places Ec both in the numeratorand the denominator. Thus, when is Ec is large, and all other interference sources aresmall (i.e. Ec >> Io), the Ec/Io ratio exhibits relatively small variance. When Ec is smallrelative to Io (i.e. Io > Ec), the variance of the Ec/Io ratio increases and more of the fadingattenuation can be seen in the measurement. Thus, confidence in static, forward linkSNR for a subscriber unit wrt any given pilot measurement is a function of that measure-ment. In addition, it seems realistic to expect that the stationarity of the Ec/Io frequency/density function is only short in time duration for most subscriber cases and dependenton the time rate of change of the pathloss.

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ner-

Figure #38. Ec/Io Confidence

The main point in the discussion above is one of having high confidence in Cell Swapand Pilot Dominance operations. Both of these have high risk associated with them suchthat triggers for both and ultimate active set composition decisions need either a lot morestudy or sufficient parameterization such that we can “parameterize our way out of ajam”. Figure #13 below shows select Ec/Io frequency distributions for the simple case1 of

as an example of the variation of Ec/Io as a function of ambientnoise where the scaler represents the fast fading process. This should reinforce thenotion in Figure #12 by asking to what distribution the value of -13 dB Ec/Io returned in aPilot Strength Measurement Message would be assigned2. Note that in this example the9 dB and 15 dB Nth/Ec distributions overlap. The situation is further complicated by not-ing that the above equation is extremely simplistic and that additional terms in thedenominator are present for increasing numbers of cells3.

1. NThermal is usually a gaussian random variate but is held constant in this experiment.2. This observation has broad implications for target selection in DAHO deployments as well as possiblyinfluencing the soft handoff model in the CDMA Static Simulation.3. For the sake of this simple demonstration, I choose to exclude delay spread, traffic channel energies, egies from interfering systems, paging and synchronization channel energies, etc.

-3-4-5-6-7-8-9-10-11-12-13-14-15-16-17-18 . . .

Ec/IoMeasurement Increasing

Confidence

DecreasingConfidence

Ec I o⁄ζ1 Ec⋅

ζ1 Ec⋅ NThermal+-------------------------------------------=

ζ1

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nt.

Figure #39. Example of Single Pilot Ec/Io as a function of Nth/Ec.

In general, the sum of several independent random variables (e.g. non-correlated fadingfrom several cells/sectors) should sum .These random variables actually make up the Io portion of the measurement and eachrandom variable has a scaling factor attributed to it’s transmission loss wrt the subscriberunit. Thus, we would expect the variance of any Ec/Io measurement to increase as thenumber of cells with “detectable” Ec increases1. Figure #14 below depicts a continuationof the above simple experiment extended to 2 and 3 Ec values. This time, the graph isdrawn as a function of NTh/Ec.

The conclusion to be drawn is that any Ec/Io value represented in a single Pilot StrengthMeasurement Message is probably a poor estimator of E[Ec/Io] (or SNR). This may bewhy the Korean manufacturers have implemented their Pilot Dominance algorithm(s)with periodic Power Measurement Report Message reporting. They have essentiallymoved the filtering process for active set pilot drops (pre-empting the T_DROP/T_TDROP process) out of the subscriber unit and into the infrastructure.

1. Of course, at some point excessive transmission loss renders the variance of any particular Ec irreleva

0

5

10

15

20

-25 -20 -15 -10 -5 0

Single Pilot Ec/Io Frequency Distributions(Thermal Noise relative to Ec, N=5000, 100 Hz, 0.02 Sampling)

0 dB15 dB9 dB

% of distribution

Ec/Io dB

BJM 05/07/97

Var X1 X2 … XN+ + +( ) Var X1( ) Var X2( ) … Var XN( )+ + +=

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)
Figure #40. Example Ec/Io variance as a function of number of pilot signals (all at equal transmission loss
and Nth/Ec.

Also, provide diagram of subscriber combining. Should have a picture with basic SHOtheory and how you really want to make sure a pilot is dead before you take it out of theactive set. “When one pilot fades, the other pilot(s) get better!”.

Proposed (Simple) Algorithm Extensions for Pilot DominanceWhile Pilot Dominance algorithms seek to maintain the minimum number of forwardlinks1, most of the work would be similar to algorithm #2 with additional parameters.Obviously, Pilot Dominance would be optimized under conditions of Full Complex SHO(which is not available).

It should be noted that adjusting handoff parameters is an indirect way of applying PilotDominance. Adjusting the T_ADD parameter for higher Ec/Io values limits the usage ofthe candidate set. Higher values of T_DROP and lower values of T_TDROP also limit thecandidate set size as well as “trimming” the active set.

1. Does Pilot Dominance also seek to optimize the reverse link?

2.5

3

3.5

4

4.5

5

5.5

6

0 2 4 6 8 10 12 14 16

Ec/Io Variance as a function of Nth/Ecand number of pilots (Ioc)

One PilotTwo Pilots

Three Pilots

VAR(Ec/Io) dB

Nth/Ec dB

BJM 05/08/97

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One possible extension to the algorithms proposed above to include minimizing theactive set size would be to drop all connections from a BTS in the event of T_TDROPtimer expiry and associated pilot Ec/Io being greater than all other pilot Ec/Io’s from thatsame BTS (as represented in the same Pilot Strength Measurement Message). Notethat this proposal relies only on the ability to simultaneously drop all connections from aBTS and does not rely on complex operations of the sort that produce simultaneous addand drop operations. Note also that the MM would have to be cognizant of how manypilots remain in the active set (under the assumption that the procedure would be suc-cessful) and ensure that at least one active set pilot remains at the end of each proce-dure execution.

In the case of adding multiple forward links, either for a new BTS or for an existing BTS,the convention of only adding those candidates whose Ec/Io value in the current PilotStrength Measurement Message helps to limit the number of forward transmitters.

Another possible extension for Pilot Dominance would be to limit the amount of softerhandoff used by a subscriber unit as a function of the number of BTS connections. Thisassumes that the primary mechanism by which forward links are added remains the sim-ple T_ADD event. An example is given in the table below. This technique also serves thefunction of keeping “open” active set slots for an emergency handoff situation. However,Note that imposing constraints on the maximum number of softer handoff connectionsallowed from a single BTS might cause us to perform more softer shuffling, etc.

Table #5.) Softer Handoff Inhibit for Pilot Dominance

Notes:Argument for Pilot Dominance is expected loads on HK and PrimeCo by the time R8 hits.How to play this off against QC proposal?

We are now implementing the opposite of handoff detection and target selection bydetecting when a pilot has gone bad and deciding how/whether to swap out.

a. Pending confirmation that current Channel Elementtracking algorithms can handle four simultaneous sec-tors’ worth of activity.

Number of BTSsInvolved in Soft

Handoff

Maximum Number ofSofter ConnectionsAllowed from One

BTS

1 4a

2 3

3 2

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Do MCCx8 and MCCx24 really have full reverse link diversity, or is it only limited to trans-mit sectors? Will?

Might have to send PMROs in those situations where the spec. precludes additionaltransmission of PSMM.

Charles Nicoll idea! Vary soft handoff parameters as a function of the number of legs insoft/softer handoff.

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Appendix A: Ec/Io Conversion Table

Ec/IoReported in

PSMM

ActualEc/IodB

Absolute ValueFunction (Integer)

0 0 15848

1 -0.5 14125

2 -1 12589

3 -1.5 11220

4 -2 10000

5 -2.5 8912

6 -3 7943

7 -3.5 7079

8 -4 6309

9 -4.5 5623

10 -5 5011

11 -5.5 4466

12 -6 3981

13 -6.5 3548

14 -7 3162

15 -7.5 2818

16 -8 2511

17 -8.5 2238

18 -9 1995

19 -9.5 1778

20 -10 1584

21 -10.5 1412

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22 -11 1258

23 -11.5 1122

24 -12 1000

25 -12.5 891

26 -13 794

27 -13.5 707

28 -14 630

29 -14.5 562

30 -15 501

31 -15.5 446

32 -16 398

33 -16.5 354

34 -17 316

35 -17.5 281

36 -18 251

37 -18.5 223

38 -19 199

39 -19.5 177

40 -20 158

41 -20.5 141

42 -21 125

43 -21.5 112

44 -22 100

45 -22.5 89

Ec/IoReported in

PSMM

ActualEc/IodB


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46 -23 79

47 -23.5 70

48 -24 63

49 -24.5 56

50 -25 50

51 -25.5 44

52 -26 39

53 -26.5 35

54 -27 31

55 -27.5 28

56 -28 25

57 -28.5 22

58 -29 19

59 -29.5 17

60 -30 15

61 -30.5 14

62 -31 12

63 -31.5 11

64 -32 10

Ec/IoReported in

PSMM

ActualEc/IodB


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Appendix B: Qualcomm Subscriber Unit Pilot Dominance Quick SummaryQualcomm is proposing a modification to the current J-STD-008 and IS-95 rules fortransmission of Pilot Strength Measurement Messages. The technique forces the sub-scriber unit to perform summation operations on active set SNR values and use those asa basis for comparison with candidate set SNRs on and individual candidate set pilotbasis. In addition, the proposal also contains a point-slope inequality (depicted below)with y-intercept and slope parameters under control of the infrastructure. This techniqueshould result in reduced PSMM messaging by the subscriber unit. It should also result inreduced soft handoff factor under judicious selection of the aforementioned parameters1.Note also that Qualcomm probably does not use the term “Pilot Dominance” to describerthe benefits provided by this proposal.

1. Obviously there’s trade-offs between forward link capacity and the integrity of the forward link.

ActiveSet_SNRii 1=

N

∑

Can

dida

te S

NR

SendPSMM

Do NotSendPSMM

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7.3 Umbrella CellJohn Toone slides from April ‘97 PrimeCo TEM

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7.4 Six Sector• Dennis Schaeffer 30 degree rotation idea.


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hetheere a thencyardg ofterigh-

7.5 DAHO optimization strategies

DAHO uses cell configuration information stored in the CBSC/BTS along with the sys-tem’s knowledge of which cells/sectors control a particular call.

Triggers on Active Set information from the last PSMM

Uses strongest Active Set pilot

Best trigger is two-way to one-way drop

Worst trigger is the completion of a pilot shuffle• Notes on Ec/Io statistics fromPilot Strength Measurement Message.



From Dan Declerck’s taxonomy:

Database Assisted handoff (DAHO) is a hard handoff triggered by the active set of tmobile station being comprised of a majority of sectors on a seam. It is triggered by TADD event of adding a pilot on the seam, or TDROP of a pilot not on the seam, whmajority of the remaining pilots in the active set are on the seam. DAHO suffers fromlargesse required to deploy it. Typically, two rows of base stations outside the frequecoverage area are required to handle all combinations of soft-handoff to trigger the hhandoff. This is due to the TADD nature of DAHO, where the mobile biases the addina pilot over the dropping of a pilot, due to the hysteresis of TTDROP used in soft/sofhandoff. This is illustrated in Figure 1. All DAHO marked sectors would include all nebor PN’s of Cells 1, 2, and 3. All DAHO sectors are indicated with aD.

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Two CDMA Carrier Domain

Single, Primary CDMA carrier domain

DD

D

DDD D

DD

DDDD

D D

Figure 1

Cell 1 Cell 2 Cell 3

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7.6 Back To Back Antennas

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en-obile

ot

target

cann-

ehead

7.7 Mobile Specification Changesfrom Dan DeClerck’s taxonomy:

This technique basically involves the mobile station vacating the traffic channel for aperiod of time to visit other frequencies to scan for pilots. This method will inherentlydegrade speech quality for the period the mobile is scanning other pilots.

Typically a DAHO technique would be employed to trigger the scan of adjacent frequcies, as it would not be prudent to degrade the speech quality constantly when the mis not on a frequency seam. The trigger for hard handoff would include the target pilchannel being TCOMP higher in strength than all active set pilots.

The advantage of this method over the others, is that the mobile actually samples theenvironment and it is used as a criteria for triggering a handoff.

7.8 Nokia/Qualcomm contribution.

This contribution set allows the subscriber unit to vacate the traffic channel to sadjacent frequencies, with two methods somewhat similar in execution.The dowside to this method is the inherent degradation of speech quality.

7.9 DeClerck/Ashley improvements.

Motorola’s improvement over this method utilizes the same traffic channel framformats, and improves speech quality by allowing the subsciber unit to vocode aof time, and provide a more consistent scan of the RF spectrum.

from Dan DeClerck’s CDG IAT/ TR45.5 WG III trip report:

Presently there are three methods for using MAHO techniques for CDMA hard

handoff:

1. 1) a one-shot method, where the mobile does a single scan of the pilots/chan-nels on other frequencies and returns with a report.

2. a periodic method, where the mobile does repeated scans at approximate inter-vals specified by the base station, and reports when those scans indicate a hand-off might be required.The pre-quel to the scan, the base gives the the mobile it’s scan list, and themobile reports it’s ability as a total time to scan all elements in the list, as well asthe longest number of consecutive frames it will be away.The base then can adjust the periodic interval the mobile is away

to scan the adjacent frequency(s).

3. a method where the mobile is hard-handed off, and if it fails, it can be optionallytold by the base to do a complete scan of all pilots in the list and report it’s results.

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TITLE:

Enhancements for inter-frequency hard handoff

SOURCE:

Motorola Inc.

Dan [email protected]

ABSTRACT:

This contribution provides a proposal to enhance the inter-frequency hardhandoff in a way that speech quality is not degraded for inter-frequencysearch intervals.

RECOMMENDATION:

That the group review the proposed changes to inter-frequency hard hand-off procedure.

Notice

©1997 Motorola, Inc.

The information contained in this contribution is provided for the sole purpose of promoting discussionwithin the TIA and is not binding on the contributor. The contributor reserves the right to add to, amendor withdraw the statements contained herein.

The contributor grants a free, irrevocable license to the Telecommunications Industry Association (TIA) toincorporate text contained in this contribution and any modifications thereof in the creation of a TIA stan-dards publication; to copyright in TIA's name any TIA standards publication even though it may includeportions of this contribution; and at TIA's sole discretion to permit others to reproduce in whole or in partthe resulting TIA standards publications.

The contributor may hold one or more patents or copyrights that cover information contained in this con-tribution. A license will be made available to applicants under reasonable terms and conditions that aredemonstrably free of any unfair discrimination.

Nothing contained herein shall be construed as conferring by implication, estoppel, or otherwise any licenseor right under any patent, whether or not the use of information herein necessarily employs an invention ofany existing or later issued patent, or copyright. The contributor reserves the right to use all material sub-mitted in this contribution for their own purposes, including republication and distribution to others.

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Introduction

The proposals that are currently being considered for inter-frequency hard handoff require a mo-bile station to periodically scan adjacent CDMA channels for an indeterminate period of time.During this period of time, the voice quality will degrade substantially. This contribution propos-es a mechanism that ensures preservation of a reasonable level of voice quality by utilizing exist-ing capabilities of IS-95 (such as Service Configuration and Negotiation). The contributionutilizes the signaling method proposed by QUALCOMM.

Recommendations

Motorola proposes that the following key enablers for hard handoff be added to PN-3693:

1 .A mechanism (negotiated using Service Configuration procedure) that allows delaying thesending of speech frames by 20 ms (one frame) and forcing the vocoder to the maximum cod-ing rate of half-rate for two frames prior to an open frame. During the open frame, the mobilestation changes frequency to scan adjacent channels for stronger pilots. It indicates the re-sult of the search to the base station, and the procedure for hard handoff continues as de-scribed in other proposals. In a frame prior to the open frame (the frame where the mobilestation scans other frequencies), the base station and mobile station transmit two half-rateframes in a single full-rate frame. Secondary Traffic is used for the second half-rate frame,as allowed in IS-95. Such a mechanism should be negotiated when it is deemed necessaryby the base station, using Service Configuration and Negotiation procedure.

2.

3 .The base station should be allowed to specify the time-period between adjacent scanning pe-riods. This gives the base station the flexibility in the trade-off between scan time and speechdegradation. This time period would be in frames, and would most likely be transmitted inthe Candidate Frequency Neighbor List Message (CFNLM) previously proposed.

4 .

5 .The specific frame used by the mobile station to scan adjacent frames may be derived usinga hash algorithm, similar to the one described in Section 6.6.7.1, with mobile stationõs ESNas the HASH_KEY modulo divided by the number of frames in the scan period. The reason tostagger the frames used is that this adjacent scanning method will probably be used in spe-cific geographic regions, and that most of the mobile stations in this region would employ thisalgorithm. Ensuring that all mobile stations do not vacate the traffic channel simultaneouslyensures a more uniform radio environment, similar to that of the traffic channel.

It is recommended that the above aspects be incorporated as part of an enhancement to the pro-posal that is adopted for inter-frequency hard handoff.

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7.10 Pilot Dominance

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7.11 Complex Handoff

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Inter-CBSC Soft Handover 11/25/97 Digital Systems Division


Inter-CBSC Soft Handover

11/25/97

Digital Systems Division

of 264

MOTOROLA CONFIDENTIAL PROPRIETARY

Cellular Infrastructure Group

PD

Contents
❑ Introduction
❑ Architecture

❑ Call Processing◗ HO Detection◗ Procedures◗ Inter-CBSC Trunk Group Resource Management◗ Restrictions◗ Example

❑ Operations and Maintenance◗ Configuration Management◗ Fault Management

➠ IC Trunk Group Mgmt.➠ IC Link Mgmt.➠ Global Reset

◗ Performance Management

MOTOROLA CONFIDENTIAL PROPRIETARYSupercell Ar c

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Introduction: Intra-CBSC Soft Handoff
❑ Intra-CBSC Soft Handoff
◗ Support of multiple active legs between the MS and Base Station within a co m➠ Mobility Control

✓ Handoff Detection and Determination✓ MS Power Control✓ RF Resource Allocation

➠ Physical Connectivity✓ Control Messaging between MM, XCDR and MCCce(s)✓ Traffic Frame Delivery to MCCce(s) (via Strau) and MSC (TerCkts)

◗ Unable to support Soft Handoff across CBSC Boundaries◗ Requires Hard Handoff to External CBSC

➠ MAHO via Pilot Beacon Configuration➠ DAHO via Configuration Parameters

Source Target(CBSC-2)(CBSC-1)

Target(CBSC-3)

= Pilot Beacons

= Internalsectors(first ring in)

1-1-2

1-1-3

1-1-1

1-2-3

1-2-2

1-2-1

1-4-3

1-4-2

1-4-1

1-3-31-3-2

1-3-1

1-5-3

1-5-2

1-5-1

1-6-3

1-6-2

1-6-1

2-1-2

2-1-3

2-1-1

2-3-2

2-3-3

2-3-1 2-2-2

2-2-2

2-2-3

2-5-2

2-5-3

1-1-1 2-4-1

2-4-2

2-4-3

2-6-2

2-6-3

2-6-1

3-1-2

3-1-3

3-1-1

3-2-2

3-2-3

3-2-1 3-3-2

3-3-3

3-3-1

A-B-C = A: CBSC #,B: BTS #,C: Sector #

= Internalsectors

MS

Hard Handoff Seam

Carrier A Carrier B

Carrier C

= Xcsectors


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Introduction: Inter-CBSC Soft Handoff
❑ Inter-CBSC Soft Handoff
◗ Support of multiple active legs between the MS and Base Station within a co mand across CBSC Boundaries.➠ Eliminates need for Pilot Beacons

✓ Frees CDMA Spectrum✓ Eliminates need to purchase Pilot Beacon Hardware (BTS Shelf, GLIs, MCCces, B

➠ Introduces a buffer zone between Intra-Carrier SHO and Hard Handoff✓ Reduces Hard Handoff Ping-Ponging between CBSCs

➠ Supports Inter-CBSC SHO simultaneously with Multiple CBSCs/MSC


Target(CBSC-3)

= Xcsectors

= Internalsectors(first ring

1-6-3

1-6-2

1-6-1

2-1-2

2-1-1

2-2-2

2-2-3

1-1-1 2-4-1

2-4-2

2-4-3

2-6-2

2-6-3

2-6-1

3-2-2

3-2-3

3-2-1 3-3-2

3-3-1

A-B-C = A: CBSCB: BTS C: Secto

= Internalsectors

IC SHO Handoff Seam

2-3-2

2-3-32-3-1

MS

3-1-2

3-1-33-1-1

2-1-3

Hard Handoff Seam (CBSC-2)

1-1-2

1-1-1

1-3-2

1-3-1

1-1-3

1-2-3

1-2-2

1-2-1

1-4-3

1-4-2

1-4-1

1-3-3

1-5-3

1-5-2

1-5-1

Hard Handoff Seam (CBSC-1)

2-2-2

2-5-3

2-5-2

3-3-3

Carrier A Carrier A

Carrier A


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ICBSC SHO: Architecture


= Ex

= In= In

ICBSC SHO: Architecture

❑ Strategy◗ Inter-connect CBSCs (that may collaborate in SHO) via

dedicated trunks➠ Control: Inter-CBSC resource allocation, power control, add/drop HO

execution➠ Traffic: 16 kbps STRAU

◗ Backhaul soft handoff legs via inter-CBSC trunks◗ Anchor handoff (non-data calls) when MS is established

(via SHO) in another CBSC◗ Inter-CBSC Soft Handoff detection via standard CDMA

MAHO◗ MSC (A+) not involved except for anchor handoff

❑ Terminology◗ Source : Anchor CBSC containing transcoding, frame

selection, and terckt to MSC◗ Target : CBSC providing soft(er) handoff legs -

backhauled to source via inter-CBSC trunks

MSC-2

CBSC-1

CBSC-2

CBSC-3

CBSC-4CBSC-5

MSC-1

isting PCM Trunks

ter-CBSC Trunkster-CBSC Trunks (Complex-KeepSoft only)

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Architectural Premise: Scope

MSC

MM XC

CBSC

BTS BTS BTS BTS

XC

OMC-R

= Voice

= Cont r

AP

Scap / LAPD

Scap/TCP-IP

NEC-A / J7

RNMP / TCP-IP

NFS,TCP-IP

Scap / LAPD


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ICBSH SHO: Architecture


B 1

: BTS Control Linomitted for clari

CBS 2

rol Path Exte Path Exten sontrol Exten s

ICBSH SHO: Architecture

FEP-1-1

FEP-1-2

XCDR

CPPGPROC

MSI

MSI

MSI

MSIMSI

Callproc1MM-1

XC-1

TS-1 BTS-2

MSC

MSCSPAN

TERCKT (PCM)

ICTRKGRPICSRCHAN(16kbps subrate)

ICLINKs(Full DS0)

FEP-2-1

FEP-2-2

XCDR

CPPGPROC

MSI

MSI

MSI

MSI MSI

Callproc1MM-2

XC-2

BTS-20BTS-202

MSCSPAN

MS

(Full DS0)

ICSPANs

PSTN

ks / FEP connectionsty

C-1 CBSC-

Src CallS-1

TargetT-1

= Cont= Voice= CP C

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Handoff Determination and Detection


Handoff Determination and Detection

❑ HO Detection◗ Performed on Anchor CBSC◗ Use of existing Handoff Detection Algorithms (TAdd,

TComp)

❑ Mobile Scans all Neighbor Candidates◗ Neighbor Set Pilot:

➠ Prior to entering Inter-CBSC SHO✓ Local Neighbors (internal sectors)✓ Selective Remote Neighbors (Xcsectors)-Path into remote CBSCis only via source Xcsector

➠ During Inter-CBSC SHO✓ Local Neighbors (internal sectors)✓ Selective Remote Neighbors (Xcsectors)✓ Neighbor list of remote sector (including “external” neighbors totarget)

◗ MS updated with merged neighbor list and parametersusing current algorithms➠ On Remote Add, backhaul additional DB Information

✓ Neighbor list of remote sector (including “external” neighbortarget)✓ Search and power control parameters

◗ “Fast pilot shuffle” supported for remote/local legmixtures

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Handoff Determination and Detection IC SHO Entry


Handoff Determination and DetectionIC SHO Entry

❑ Adding IC SHO (Initial and Subsequent IC SHOADDs)◗ Performed on Anchor CBSC◗ MAHO Indication used to Select SHO Candidate (Remote

or Local)◗ Database parameter at IC Trunk Group level

(HOOverRide) specifies entry criteria➠ No_Handoff

✓ Overrides XCSECTOR Handoff Method specification(HandOffMeth)✓ No Hard or Soft Handoffs allowed to remote CBSC.

➠ Hard✓ Overrides XCSECTOR Handoff Method specification(HandOffMeth)✓ Inhibits IC SHO, new Active Leg added via Hard Handoff(Must pass current Inter-CBSC Hard Handoff checks)

➠ No_OVERRIDE✓ Use XCSECTOR Handoff Method specification(HandOffMeth) None

◗ Database parameter at XCSECTOR level (HandOffMeth)➠ None

✓ No Handoff Performed➠ Hard

✓ Perform Hard Handoff➠ Soft_Trunking

✓ Attempt IC SHO, could override via IC Trunk Group: HOOverRideSetting

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Handoff Determination and Detection IC SHO Exit Criteria


Handoff Determination and DetectionIC SHO Exit Criteria

◗ Performed on Anchor CBSC◗ Checked at completion of ADD or DROP Operation

✓ Fast Pilot Shuffling viewed as atomic operation◗ Active Calls: Database parameter at source CBSC level

(AnchorHoMeth) controls exiting criteria➠ “Legs_Remote”

✓ No HO legs are in source CBSC (NOTE: multiple targets may beinvolved)✓ No HO legs are “known” (i.e., correspond to an Xcsector) to thesource✓ Hard handoff is not otherwise blocked (e.g., data call)

➠ “No_Legs”✓ No HO legs are in source CBSC (NOTE: multiple targets may beinvolved)✓ Hard handoff is not otherwise blocked (e.g., data call)

➠ “Keep_Soft” (Simple)✓ Support call with only MAHO backhauled information

◗ Anchor Handoff for Active Calls➠ Leg with best signal strength (Ec/Io) is chosen for hard-handoff

candidate➠ Conventional CDMA-to-CDMA hard handoff employed

◗ IC Target Failure➠ Failure in Target Side Procedure

✓ Results in Call Teardown◗ MS Re-enters Anchor CBSC

➠ No Remaining Active Legs on Target CBSC◗ Call Release

➠ Normal Call Release (e.g., Land Release) or Abnormal Call Release(e.g., Drop Call)

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ICBSC SHO: Call Processing - SHO Detection

Step Active SetNeighbor Candidate List

(Assume: (1) sector’s neighbors are adjacent sectors and (2) ignorelatent neighbor list from last drop)

Comments

1 1-3-1, 1-3-2 1-1-2, 1-3-3, 1-5-1, 2-3-3,3-1-2 Initial Conditions


Target(CBSC-3)

= Xcsectors


1-1-2

1-1-3

1-1-1

1-2-3

1-2-2

1-2-1

1-4-3

1-4-2

1-4-1

1-3-3

1-3-2

1-3-1

1-5-3

1-5-2

1-5-1

1-6-3

1-6-2

1-6-1

2-1-2

2-1-3

2-1-1

2-3-2

2-3-3

2-3-1 2-2-2

2-2-2

2-2-3

2-5-2

2-5-3

1-1-1 2-4-1

2-4-2

2-4-3

2-6-2

2-6-3

2-6-1

3-1-2

3-1-3

3-1-1

3-2-2

3-2-3

3-2-1 3-3-2

3-3-3

3-3-1


= Internalsectors

1


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Comments


2 1-3-1, 1-3-2,2-3-3 1-1-2, 1-3-3, 1-5-1,2-3-1, 2-3-2,3-1-3 Add 2-3-3


Target(CBSC-3)

= Xcsectors


1-1-2

1-1-3

1-1-1

1-2-3

1-2-2

1-2-1

1-4-3

1-4-2

1-4-1

1-3-3

1-3-2

1-3-1

1-5-3

1-5-2

1-5-1

1-6-3

1-6-2

1-6-1

2-1-2

2-1-3

2-1-1

2-3-2

2-3-32-3-1 2-2-2

2-2-2

2-2-3

2-5-2

2-5-3

1-1-1 2-4-1

2-4-2

2-4-3

2-6-2

2-6-3

2-6-1

3-1-2

3-1-3

3-1-1

3-2-2

3-2-3

3-2-1 3-3-2

3-3-3

3-3-1


= Internalsectors

12


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Comments


2 1-3-1, 1-3-2,2-3-3 1-1-2, 1-3-3, 1-5-1,2-3-1, 2-3-2,3-1-3 Add 2-3-3

3 1-3-2,2-3-3,3-1-3 1-1-2, 1-3-1, 1-3-3, 1-5-1,2-3-1, 2-3-2,3-1-1, 3-1-2 Drop 1-3-1,Add 3-1-3


Target(CBSC-3)

= Xcsectors


1-1-2

1-1-3

1-1-1

1-2-3

1-2-2

1-2-1

1-4-3

1-4-2

1-4-1

1-3-3

1-3-2

1-3-1

1-5-3

1-5-2

1-5-1

1-6-3

1-6-2

1-6-1

2-1-2

2-1-3

2-1-1

2-3-2

2-3-32-3-1 2-2-2

2-2-2

2-2-3

2-5-2

2-5-3

1-1-1 2-4-1

2-4-2

2-4-3

2-6-2

2-6-3

2-6-1

3-1-2

3-1-33-1-1

3-2-2

3-2-3

3-2-1 3-3-2

3-3-3

3-3-1


= Internalsectors

12

3


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Comments


2 1-3-1, 1-3-2,2-3-3 1-1-2, 1-3-3, 1-5-1,2-3-1, 2-3-2,3-1-3 Add 2-3-3

3 1-3-2,2-3-3,3-1-3 1-3-1, 1-3-3, 1-5-1,2-3-1, 2-3-2,3-1-1, 3-1-2 Drop 1-3-1,Add 3-1-3

4 2-3-2,2-3-3, 3-1-3 1-1-2, 1-3-1, 1-3-2, 1-5-1,2-3-1, 2-5-3,3-1-1, 3-1-2 Drop 1-3-2,Add 2-3-2


Target(CBSC-3)

= Xcsectors


1-1-2

1-1-3

1-1-1

1-2-3

1-2-2

1-2-1

1-4-3

1-4-2

1-4-1

1-3-3

1-3-2

1-3-1

1-5-3

1-5-2

1-5-1

1-6-3

1-6-2

1-6-1

2-1-2

2-1-3

2-1-1

2-3-22-3-3

2-3-1 2-2-2

2-2-2

2-2-3

2-5-2

2-5-3

1-1-1 2-4-1

2-4-2

2-4-3

2-6-2

2-6-3

2-6-1

3-1-2

3-1-33-1-1

3-2-2

3-2-3

3-2-1 3-3-2

3-3-3

3-3-1


= Internalsectors

12

34


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Comments


2 1-3-1, 1-3-2,2-3-3 1-1-2, 1-3-3, 1-5-1,2-3-1, 2-3-2,3-1-3 Add 2-3-3

3 1-3-2,2-3-3,3-1-3 1-3-1, 1-3-3, 1-5-1,2-3-1, 2-3-2,3-1-1, 3-1-2 Drop 1-3-1,Add 3-1-3

4 2-3-2,2-3-3, 3-1-3 1-1-2, 1-3-1, 1-3-2, 1-5-1,2-3-1, 2-5-3,3-1-1, 3-1-2 Drop 1-3-2,Add 2-3-2

5 2-3-3, 2-3-2, 2-5-3 1-1-2, 1-3-1,2-3-1, 2-5-1, 2-5-2 Drop 3-1-3, Add 2-5-3 (3-1-1 exclu


Target(CBSC-3)

= Xcsectors


1-1-2

1-1-3

1-1-1

1-2-3

1-2-2

1-2-1

1-4-3

1-4-2

1-4-1

1-3-3

1-3-2

1-3-1

1-5-3

1-5-2

1-5-1

1-6-3

1-6-2

1-6-1

2-1-2

2-1-3

2-1-1

2-3-22-3-3

2-3-1 2-2-2

2-2-2

2-2-3

2-5-2

2-5-32-5-1 2-4-1

2-4-2

2-4-3

2-6-2

2-6-3

2-6-1

3-1-2

3-1-3

3-1-1

3-2-2

3-2-3

3-2-1 3-3-2

3-3-3

3-3-1


= Internalsectors

12

34 5


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Comments


2 1-3-1, 1-3-2,2-3-3 1-1-2, 1-3-3, 1-5-1,2-3-1, 2-3-2,3-1-3 Add 2-3-3

3 1-3-2,2-3-3,3-1-3 1-3-1, 1-3-3, 1-5-1,2-3-1, 2-3-2,3-1-1, 3-1-2 Drop 1-3-1,Add 3-1-3

4 2-3-2,2-3-3, 3-1-3 1-1-2, 1-3-1, 1-3-2, 1-5-1,2-3-1, 2-5-3,3-1-1, 3-1-2 Drop 1-3-2,Add 2-3-2

5 2-3-3, 2-3-2, 2-5-3 1-1-2, 1-3-1,2-3-1, 2-5-1, 2-5-2 Drop 3-1-3, Add 2-5-3 (3-1-1 exclu

6 2-3-2, 2-5-3 2-3-1, 2-3-2, 2-5-1, 2-5-2 Drop 2-3-3(assume2-5-3 has best E


Target(CBSC-3)

= Xcsectors


1-1-2

1-1-3

1-1-1

1-2-3

1-2-2

1-2-1

1-4-3

1-4-2

1-4-1

1-3-3

1-3-2

1-3-1

1-5-3

1-5-2

1-5-1

1-6-3

1-6-2

1-6-1

2-1-2

2-1-3

2-1-1

2-3-22-3-3

2-3-1 2-2-2

2-2-2

2-2-3

2-5-2

2-5-32-5-1 2-4-1

2-4-2

2-4-3

2-6-2

2-6-3

2-6-1

3-1-2

3-1-3

3-1-1

3-2-2

3-2-3

3-2-1 3-3-2

3-3-3

3-3-1


= Internalsectors

12

34 5 6


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Comments


2 1-3-1, 1-3-2,2-3-3 1-1-2, 1-3-3, 1-5-1,2-3-1, 2-3-2,3-1-3 Add 2-3-3

3 1-3-2,2-3-3,3-1-3 1-3-1, 1-3-3, 1-5-1,2-3-1, 2-3-2,3-1-1, 3-1-2 Drop 1-3-1,Add 3-1-3

4 2-3-2,2-3-3, 3-1-3 1-1-2, 1-3-1, 1-3-2, 1-5-1,2-3-1, 2-5-3,3-1-1, 3-1-2 Drop 1-3-2,Add 2-3-2

5 2-3-3, 2-3-2, 2-5-3 1-1-2, 1-3-1,2-3-1, 2-5-1, 2-5-2 Drop 3-1-3, Add 2-5-3 (3-1-1 exclu

6 2-3-2, 2-5-3 2-3-1, 2-3-2, 2-5-1, 2-5-2 Drop 2-3-3(assume2-5-3 has best E

7 2-5-3 2-3-2, 2-5-1, 2-5-2,3-1-1 Anchor Handoff to CBSC-2-5-3


Target(CBSC-3)

= Xcsectors


1-1-2

1-1-3

1-1-1

1-2-3

1-2-2

1-2-1

1-4-3

1-4-2

1-4-1

1-3-3

1-3-2

1-3-1

1-5-3

1-5-2

1-5-1

1-6-3

1-6-2

1-6-1

2-1-2

2-1-3

2-1-1

2-3-2

2-3-3

2-3-1 2-2-2

2-2-2

2-2-3

2-5-2

2-5-32-5-1 2-4-1

2-4-2

2-4-3

2-6-2

2-6-3

2-6-1

3-1-2

3-1-3

3-1-1

3-2-2

3-2-3

3-2-1 3-3-2

3-3-3

3-3-1


= Internalsectors

12

34 5 67


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PD

ICBSC SHO: Call Processing - Procedur e
❑ Orchestrated via Inter-CBSC SCAP Messaging (Approx. 20 new/m o
❑ Inter-CBSC Initial Soft Handoff Add◗ Establish first Soft HO leg, for a given call, on a particular target CBSC◗ Allocates Target MM, Target XC CPP GPROC, IC-SRCHAN, Target MCCce / T C

❑ Inter-CBSC Subsequent Soft/Softer Handoff Add◗ Establish second or third Soft[er] HO legs, for a given call, on a particular t a◗ Softer HO only requires allocation of target BTS TCHwc, (no IC-SRCHAN / t a

❑ Inter-CBSC Soft/Softer Handoff Drop◗ Remove a remote Soft[er] HO leg, for a given call, from a particular target C B◗ Soft HO drop deallocates IC-SRCHAN and target MCCce / TCHwc◗ Softer HO drop deallocates target BTS TCHwc

❑ Inter-CBSC Disconnect◗ Remove all target Soft[er] HO legs and Target State

➠ Deallocate Target XC CPP➠ Deallocate Target BTS MCCce(s) and TCHwc(s)➠ Deallocate IC-SRCHAN(s)

◗ Applies to Last Soft HO drop on Target and Call Release/Teardown

❑ Inter-CBSC Target Failure◗ Indication from Target to Source of non-Recoverable Failure (e.g., Equipme n◗ Results in Source-initiated Call Teardown


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ICBSC SHO: Call Processing - Inter-CBSC Trunk Group Resource Mgmt.


ICBSC SHO: Call Processing - Inter-CBSC Trunk Group Resource Mgmt.

❑ Single ICBSC Trunk Group Between two CBSCs

❑ Provisions for two-way trunks (recommended)◗ A given IC-SRCHAN may be Allocated from either CBSC◗ Simple “Opposite End” Allocation Policy◗ Glare Hold/Release Arbitration Needed (CP Retry: Similar

to Handling of other Errors)

❑ Provisions for one-way trunks (fallback)◗ All IC-SRCHANs in a given IC SPAN may only be Allocated

by one of the two CBSCs◗ Allocation Policy may be “Opposite End” or “Round

Robin”◗ Glare Hold/Release Arbitration Not Required

❑ Detection/Cleanup of IC-SRCHANs in InconsistentState◗ Detect and Automatically Recover from “Hung” IC-

SRCHANs➠ Stranded Target CBSC (MM and XC)➠ Stranded XC State (connection, GPROC, etc.)

◗ When CP Detects IC-SRCHAN in Inconsistent State➠ IC-SRCHAN is marked “Unavailable” (removed from future allocation

considerations)➠ Source/Target CP Messaging will force IC-SRCHAN “Unavailable” on

Both CBSCs➠ Source CBSC will Trigger Fault Management IC-SRCHAN “reset” to

recover IC-SRCHAN

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ICBSC SHO: Call Processing - Restrictions


ICBSC SHO: Call Processing - Restric-tions

❑ Anchor Handoff Required (except data calls)

❑ SHO Adds may not be performed to “3rd Party”CBSC sectors

❑ Hard Handoffs Blocked while Call is Configured inInter-CBSC SHO◗ CDMA to Analog◗ CDMA to CDMA (except for anchor handoff)

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ICBSC SHO: Call Processing - Initial Conditions


B 1


CBS 2

ICBSC SHO: Call Processing - Initial Con-ditions

FEP-1-1

FEP-1-2

XCDR

CPPGPROC

MSI

MSI

MSI

MSIMSI

Src CallS-1

Callproc1MM-1

XC-1

TS-1 BTS-2

MSC

MSCSPAN

TERCKT (PCM)


ICLINKs(Full DS0)

FEP-2-1

FEP-2-2

XCDR

CPPGPROC

MSI

MSI

MSI

MSI MSI

Callproc1MM-2

XC-2

BTS-20BTS-202

MSCSPAN

MS

(Full DS0)

ICSPANs

PSTN


C-1 CBSC-

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ICBSC SHO: Call Processing - Inter-CBSC Initial Soft Add


B 1


CBS 2

ICBSC SHO: Call Processing - Inter-CBSC Initial Soft Add

FEP-1-1

FEP-1-2

XCDR

CPPGPROC

MSI

MSI

MSI

MSIMSI

Src CallS-1

Callproc1MM-1

XC-1

TS-1 BTS-2

MSC

MSCSPAN

TERCKT (PCM)


ICLINKs(Full DS0)

FEP-2-1

FEP-2-2

XCDR

CPPGPROC

MSI

MSI

MSI

MSI MSI

TargetT-1

Callproc1MM-2

XC-2

BTS-20BTS-202

MSCSPAN

MS

(Full DS0)

ICSPANs

PSTN


C-1 CBSC-

of 264

ICB

SC

SH

O: C

all Processing - Inter-C

BS

C Initial S

oft Add P

rocedure

of 264

Motorola C


ICB

SC

SH

O: C

all Processing - Inter-

CB

SC

Initial Soft A

dd Procedure

Procedure U

nique to Inter-CB

SC

SH

O

SRC_MM TRG_MM SRC_XC TRG_XC ALL_TCH TARG_TCH MS

age

pilot strength & phase]

d

ission Indication

sage

rder

[7] ICP: CDMA XC Direction

[1] RF: Pilot Strength Measurement Mess

[Pilot strengths, Pilot phases, reference [2] ICP: CDMA Handoff Recognized [Soft Add]

[3] ICP: CDMA IC Initial Handoff Request

1. Detects initial IC SHO add event 2. Allocates an ICsrchan]

[4] ICP: CDMA IC Handoff Request Ack

1. Allocate Target Call Job 2. ICsrchan Update-Mark Busy 3. Allocate MCCce and TCHwc from BTS/Carrier

[5] ICP: CDMA XC Connect Call

1. Establish Target Inter-CBSC Path Connect[6] ICP: CDMA XC Connect Call Ack

1. Path Connect Complete

1. Establish Source Inter-CBSC Path Connect 2. Add New Active Pilot

[8] ICP: CDMA Handoff Channel Assigne

[9] ICP: CDMA Forward Channel Transm

[10] RF: Extended Handoff Direction Mes

1. Inform mobile of new Active Set

[11] RF: Handoff Completion Message

[12] RF: Base Station Acknowledgment O

[13] ICP: CDMA Handoff State Change

ICBSC SHO: Call Processing - Inter-CBSC Subsequent Softer Add


B 1


CBS 2

ICBSC SHO: Call Processing - Inter-CBSC Subsequent Softer Add

FEP-1-1

FEP-1-2

XCDR

CPPGPROC

MSI

MSI

MSI

MSIMSI

Src CallS-1

Callproc1MM-1

XC-1

TS-1 BTS-2

MSC

MSCSPAN

TERCKT (PCM)


ICLINKs(Full DS0)

FEP-2-1

FEP-2-2

XCDR

CPPGPROC

MSI

MSI

MSI

MSI MSI

TargetT-1

Callproc1MM-2

XC-2

BTS-20BTS-202

MSCSPAN

MS

(Full DS0)

ICSPANs

PSTN


C-1 CBSC-

of 264

ICBSC SHO: Call Processing - Source Dropped, Target Dropped & Added


B 1


CBS 2

ICBSC SHO: Call Processing - SourceDropped, Target Dropped & Added

FEP-1-1

FEP-1-2

XCDR

CPPGPROC

MSI

MSI

MSI

MSIMSI

Src CallS-1

Callproc1MM-1

XC-1

TS-1 BTS-2

MSC

MSCSPAN

TERCKT (PCM)


ICLINKs(Full DS0)

FEP-2-1

FEP-2-2

XCDR

CPPGPROC

MSI

MSI

MSI

MSI MSI

TargetT-1

Callproc1MM-2

XC-2

BTS-20BTS-202

MSCSPAN

MS

(Full DS0)

ICSPANs

PSTN


C-1 CBSC-

of 264

ICB

SC

SH

O: C

all Processing - Inter-C

BS

C Initial S

oft Last Drop P

rocedure

of 264

Motorola C


ICB

SC

SH

O: C

all Processing - Inter-

CB

SC

Initial Soft Last D

rop ProcedureP

rocedure Unique to Inter-C

BS

SRC_MM TRG_MM SRC_XC TRG_XC ALL_TCH TRG_TCH MS

ength & phase]

[1] RF: Pilot Strength Measurement Message

[Pilot strengths, Pilot phases, reference pilot str

[2] ICP: CDMA Handoff Recognized [Soft Drop]

[3] ICP: CDMA XC Direction

1. Remove Inter-CBSC Path Connect 2. Remove Pilot from Active Pilot Set

[4] ICP: CDMA Handoff State Change

[5] RF: Extended Handoff Direction Message

[6] RF: Handoff Completion Message

[7] RF: Base Station Acknowledgment Order

[8] ICP: CDMA Handoff Successful#

[9] ICP: CDMA IC Disconnect

1. Detects remove of last pilot from Target CBSC 2. Initiates Last Drop procedure on Target CBSC

[10] ICP: CDMA XC Disconnect Call

1. Disconnect Inter-CBSC Path Connect 2. Terminate XC Call Job

[11] Execute Radio Channel Release Procedure

[12] Radio Channel Release Procedure Complete

1. Deallocate BTS Resource[13] ICP: CDMA XC Disconnect Call Ack

ICBSC SHO: Call Processing - Anchor Handoff (CBSC-1 to CBSC-2) Completed


B 1


CBS 2

ICBSC SHO: Call Processing - AnchorHandoff

(CBSC-1 to CBSC-2) Completed

FEP-1-1

FEP-1-2

XCDR

CPPGPROC

MSI

MSI

MSI

MSIMSI

Callproc1MM-1

XC-1

TS-1 BTS-2

MSC

MSCSPAN

TERCKT (PCM)


ICLINKs(Full DS0)

FEP-2-1

FEP-2-2

XCDR

CPPGPROC

MSI

MSI

MSI

MSI MSI

SourceS-2

Callproc1MM-2

XC-2

BTS-20BTS-202

MSCSPAN

MS

(Full DS0)

ICSPANs

PSTN


C-1 CBSC-

of 264



PD

ICBSC SHO: O&M - Configuration Manage m
❑ Trunk Groups Named From CBSC Perspective
◗ A Single Trunk Group Typically will have Two Distinct Names◗ A Single Trunk Group may have the Same Name only if:

➠ The involved CBSCs have the same ID➠ The involved CBSCs belong to different OMC-R

◗ Child Devices (ICSPAN, ICSRCHAN, ICLINK) named Consistent with Trunk G◗ Contained Devices must be Provisioned/Named Symmetrically on Endpoint

❑ Trunk Group Unique ID Unambiguously Identifies Trunk Grou p◗ Must be Provisioned Identically on Endpoint CBSCs◗ ICTRKGRPUid and ICSRCHAN low IDs (ICSPAN-ICDS0-ICSRCHAN) Exchan g

CBSC-1

CBSC-4

CBSC-3

CBSC-2

ICTRKGRP-1-1

ICTRKGRP-2-1

ICTRKGRP-2-2

ICTRKGRP-2-3

ICTRKGRP-4-1

ICTRKGRP-4-3

ICTRKGRP-4-2

ICTRKGRP-1-2

ICTRKGRP-1-3

ICTRKGRP-3-3

ICTRKGRP-3-1ICTRKGRP-3-2

1

24

53

6

# = ICTRKGRPUid


S - 255 of 264

of 264

LEGEND:

MM Add/DelMMI

Add/Del

Required Assoc. when Provisioned

Optional Assoc. when Provisioned

Non-Parental Assoc. enforcedwhen deleting

MIB only objectCBSC

OMC

Add/Del OMCR

FRAME

DEFAULTS

ICB

SC

SH

O- C

onfiguration Managem

ent Provisioning H

ierarchy

Motorola C


ICB

SC

SH

O- C

onfiguration Managem

eP

rovisioning Hierarchy

CSM

Add/Del

GLI

RGLI

MDM

BTS

BTSLINK C7LINK

MSI

MSC SPAN

BTS SPAN

CBSC

BTSDS0

TERCKT

MSC

SRCHAN

MCC

Add/Del

Add/Del

Add/Del

Add/Del

Add/Del

Add/Del BTSSPAN

Add/Del

Add/Del Add/Del

XASECT

Add/Del

XASECT

CARRIER

TCHwc

Add/Del

CARRIER

Add/Del

MDM

BBX(R)Add/Del

XCSECT

Add/Del

XCSECT

XCLINK

Add/Del

(CPP)

NCON

Add/Del

XCLINK

FEP(R)

(OMP)

MSI

TERCKTBTSLINK C7LINK

MSCSPAN

MMI

FEP

XCLINK

BTS

BBX

GLI

CSM

BTS

CBSC

SERVOPT

Add/Del

SERVOPT

OUTROUTE

INROUTECraft only object

ICTRKGRP

Add/Del

ICTRKGRP

FRAME

RFDS

MMXCLAN

BDC*

SECTOR

n

LPA

MCCCE

Add MDM or

Add CSM

MCC

Add/Del

ICSPAN

ICSPAN

ICLINK



PD

ICBSC SHO: O&M Fault Management - ICLIN K
❑ ICLINK is Fundamental Fault Managed Device
◗ Control-Traffic-Carrying ICLINKs Managed Active/Standby (INS_ACT, INS_S B➠ First Two ICSPANs in ICTRKGRP Contain Control-Traffic-Carrying ICLINKs➠ Links are Aligned such that both CBSCs “Agree” on Active/Standby Link Status➠ Single/Symmetric Active Link Eliminates Message Ordering Issues

◗ ICLINKs on ICSPANs 3 - N are for Span Monitoring Purposes Only (INS, OO S◗ Standard DSM Operations Supported (Enable, Disable, Cutover, Uncut)◗ Link Changeover (Failure/Disable) is Automatic

❑ ICSPAN and Contained ICSRCHANs Managed via ICLINK◗ Every ICSPAN must contain one and only one ICLINK for Span Monitoring◗ Status of Span and Availability of its Resources (ICSRCHANs) Follows ICLI N

ICSPAN-1-1-1

ICSPAN-1-1-2

ICSPAN-1-1-3

ICSPAN-1-1-N

ICSPAN-2-1-1

ICSPAN-2-1-2

ICSPAN-2-1-3

ICSPAN-2-1-N

ICSPAN-1-1-1

ICSPAN-1-1-2

ICSPAN-1-1-3

ICSPAN-2-1-1

ICSPAN-2-1-2

ICSPAN-2-1-3

ICSPAN-1-1-N ICSPAN-2-1-N

ACTIVE

STANDBY

MONITOR

MONITOR

CBSC-1 CBSC-2MSIMSIMSI

MSI

MSI

MSIMSI

MSI

FEP-1-1-1

FEP-1-1-2

FEP-1-1-3

FEP-2-1-1

FEP-2-1-2

FEP-2-1-3

FEP-2-1-4

ICTRKGRP-1-1 ICTRKGRP-2-1


S - 257 of 264

ICBSC SHO: O&M Fault Management - ICTRKGRP Mgmt.


ICBSC SHO: O&M Fault Management -ICTRKGRP Mgmt.

❑ ICSRCHAN is the “allocatable” Resource Derivedfrom ICTRKGRP

❑ ICSRCHAN Status for ICSPAN Reported viaassociated ICLINK Status◗ Reports ICSRCHAN: INS/OOS◗ Reports ICSRCHAN: BUSY/IDLE/CPUNAVAIL

❑ RESCHAN Command Supported to “Reset”ICSRCHAN◗ Coordinated by FM between both Affected CBSCs◗ Attempts to Release Call Associated with ICSRCHAN via

CP Clearing◗ Forces XC Cleanup of ICSRCHAN Connection◗ Upon Success, Idles ICSRCHAN

❑ RESCHAN Processing may be Initiated by “source”CBSC when ICSRCHAN inconsistency is detected

of 264

ICBSC SHO: O&M Fault Management - ICSRCHAN Status Mapping


ICLINK StatuICSRCHANisplay Statu

OT_EQUIPP not displaye

PRE_CUT PRE_CUT

OOS_MANOOS_PAR,

OOS_AUTOOOS_FLTD

NONE

PRE_CUT

OOS

OOS

INS_CMPNS_ACT, INS_

INS

NONE

PRE_CUT

INS_IDLE

OOS_AUTO

OOS_AUTO

INS_BUSY

INS_CMPN

OOS_AUTO

OOS_AUTO

ICBSC SHO: O&M Fault Management -ICSRCHAN Status Mapping

❑ ICSRCHAN Display Status Mapping

s TypeICSRCHAN

Inhibit StatusICSRCHAN Allo-

cation StatusICSRCHAN FM

Status D

ED - - - -

- - - -

,

,

NON-TRAFFIC - - -

TRAFFIC INHIBITED - -

NOT INHIBITED IDLE CAMPON

OOS

,SBY,

NON-TRAFFIC - - -

TRAFFIC INHIBITED - -

NOT INHIBITED IDLE NULL

CAMPON

OOS

BUSY NULL

CAMPON

CPUNAVAIL NULL

CAMPON

of 264

ICB

SC

SH

O: O

&M

Fault Managem

ent - ICS

RC

HA

N S

tatus Com

mand E

xample

of 264

Motorola C


ICB

SC

SH

O: O

&M

Fault Managem

ent -IC

SR

CH

AN

Status C

omm

and Exam

ple

1.00005 00057

1.00005 00057

E

BRATE 3

NES_IDLES_IDLES_IDLES_IDLES_IDLES_IDLES_IDLES_IDLES_IDLES_IDLES_IDLES_IDLES_IDLES_IDLES_IDLES_IDLES_IDLES_IDLES_IDLES_IDLES_IDLES_IDLES_IDLE

tomahawk9-010001 > status iclink-1-2-4 add010001-00005 COMMAND ACCEPTED

ICLINK-1-2-4 97-05-26 07:49:02 tomahawk9 MM-1 D01000 INFO:3 “Command in Progress” STATUS=STARTED

ICLINK-1-2-4 97-05-26 07:49:03 tomahawk9 MM-1 D01000 INFO:35 “ICLINK Status Response” TELSTATE=INS PROCEDURE=NONE PHYSTATE=NON HDWRTYPE=None

DS0 SUBRATE 0 SUBRATE 1 SUBRATE 2 SU --- --------- --------- --------- --------- 1 NONE NONE NONE NO 2 NONE INS_IDLE INS_IDLE IN 3 NONE INS_IDLE INS_IDLE IN 4 NONE INS_IDLE INS_IDLE IN 5 NONE INS_IDLE INS_IDLE IN 6 NONE INS_IDLE INS_IDLE IN 7 NONE INS_IDLE INS_IDLE IN 8 NONE INS_IDLE INS_IDLE IN 9 NONE INS_IDLE INS_IDLE IN 10 NONE INS_IDLE INS_IDLE IN 11 NONE INS_IDLE INS_IDLE IN 12 NONE INS_IDLE INS_IDLE IN 13 NONE INS_IDLE INS_IDLE IN 14 NONE INS_IDLE INS_IDLE IN 15 NONE INS_IDLE INS_IDLE IN 16 NONE INS_IDLE INS_IDLE IN 17 NONE INS_IDLE INS_IDLE IN 18 NONE INS_IDLE INS_IDLE IN 19 NONE INS_IDLE INS_IDLE IN 20 NONE INS_IDLE INS_IDLE IN 21 NONE INS_IDLE INS_IDLE IN 22 NONE INS_IDLE INS_IDLE IN 23 NONE INS_IDLE INS_IDLE IN 24 NONE INS_IDLE INS_IDLE IN

ICBSC SHO: O&M Fault Management - Global Reset (MM callproc1 Restart)


ICBSC SHO: O&M Fault Management -Global Reset

(MM callproc1 Restart)

❑ Procedure Executed when MM callproc1 processrestarts◗ Coordinated by Fault Mgmt. as a “Global Reset” /

Restarting CBSC controls◗ Clear all local Call State and all remote Call State (source/

target) dependent upon local CBSC1. callproc1 restarts2. Restarting callproc1 blocks new traffic (Originations.

Terminations, Hard Handins, IC SHO Handins)3. callproc1 informs FM of Restart4.1 callproc1 cleans up internal resource state (Radio Chnl Release,

CPPs, TerCkts)4.2 FM camps-on all ICSRCHANs for all IC Trunk Groups4.2.a FM initiates Global Reset to each ICTRKGRP4.2.b.1 FM sends Go-Ins to XC (XC tears down all call state information)4.2.b.2 Upon Go-Ins Complete (acknowledge msg received), new traffic

allowed3. Remote CBSCs: FM Camps-on ICSRCHANs and “locally”

Releases Calls (target/source) using ICTRKGRP3. After CP Cleanup Completes, FM on remote CBSCs execute

ICSRCHAN Reset for “stuck” ICSRCHANs3. Upon completion, remote CBSCs Acknowledge Global Reset3. When local cleanup is complete (step 5 & 7) and a remote CBSC

has ack’d, Signal Global Reset Complete to other CBSC3. Remote CBSC uncamp-on ICSRCHANs

of 264

ICBSC SHO: O&M Fault Management - Global Reset Diagram


ICBSC SHO: O&M Fault Management -Global Reset Diagram

Release

C

CallRelease

Release

callproc

Global TRKGRP Reset

Global TRKGRP Reset Complete

Global TRKGRP Reset Acksc_devom sc_devom

XCXC

Radio Channel Radio Channe

processrestarts

CPPICSRCHAN

Reset

CPPICSRCHAN

Reset

callproc

ICSRCHANIdled

XC Releaseadio Channel/C Disconnect

Call

XC ReleaseRadio Channel/XC Disconnect

Call

1

3

3

3c

3a

5

4a

4b 4c5

6

7

4 8

2 Block New Calls

CP informs FM

FM Camps On ICSrchans

alls

of 264



PD

ICBSC SHO: O&M - Performance Manage m
❑ Traffic Engineering Measurements:
◗ ICTRKGRP Measurements➠ Members Equipped➠ All Channels Busy➠ Out of Service Times➠ Total Usage/Attempts/Overflows➠ Anchor Usage/Attempts/Overflows➠ Glare/Glare Retry/Glare Retry Success

◗ ICSRCHANs Measurements➠ Out of Service Times (CP Unavail. or OOS)➠ Total Usage/Attempts➠ Glare

◗ Carrier Site Level➠ IC Group Usage

◗ Carrier/Sector Level➠ IC TCHwc Usage/Attempts/Overflows

◗ MCCce Level➠ IC Usage

❑ Performance Measurements:◗ Anchor Trunk Group, Anchor Sector/Carrier, Target Sector/Carrier Level

✓ Initial Req/Attempts/Failures✓ Subsequent Soft Req/Attempts/Failures✓ Subsequent Softer Req/Attempts/Failures✓ Intermediate Soft Drop Attempts/Failures✓ Intermediate Softer Drop Attempts/Failures✓ Last Drop Attempt/Failures✓ IC RF Loss (only at Sector/Carrier level)


S - 263 of 264

ICBSC SHO: O&M - Call Detailed Log (CDL)


ICBSC SHO: O&M - Call Detailed Log(CDL)

❑ Call Detail Log (CDL)◗ Extension to Store Remote CBSC Identifiers for Remote

Call Leg Information➠ ADD MM Sys_ID Number to various fields➠ ID-10 New Release Event (INIT_MM_REL_EVENT) for IC Target

Failure➠ ID-11 Modified “HO Summary”➠ ID-12 “Last_HO_BLOCK_Cause” Extended to include IC SHO

Blocked causes.➠ ID-13 (New) “IC SHO Summary Information

✓ Initial SHO Info: Initial external Target (target MM and Sector),Local Source Information (Current Source Sector on Active Set)✓ Last SHO Info: external Target (target MM and Sector), LocalSource Information (Current Source Sector on Active Set)✓ Last Target✓ Initial IC SHO Attempts/call✓ IC SHO CBSC Interaction count (Number of different CBSCs MSwas in IC SHO with)

◗ Cleanup of Some Call Leg Information Fields

of 264


ta-re areas

of ear-s theiffi-r

entsta-

ndor

encee.

rivers,

hase

7.12 Edge Sensingfrom Dan DeClerck’s taxonomy:

7.13 Description and discussion.

This method uses whatever information is available to determine if the mobile stion is at the edge of a cell. This method has not been fully investigated, but thea number of techniques that can be employed to determine when the mobile hcome to the limit of a cell boundary. Typically, the information required mightinclude: PN phase measurements from the receiver of the base station (timing liest arriving ray) to determine RF path distance to base station, mobile station’Pilot power measurements to get a rough approximation of reverse pathloss inpresence of interference, and forward Frame Erasure Rate (FER). One of the dculties of using this method is in areas of excessive amounts of multipath and/onon-dominant pilots. In this environment, the mobile station may be constantlychanging it’s reference PN, and thus slewing it’s transmit timing. This environmof uncertain mobile station transmit timing would negate the ability of the base tion to use PN phase measurements effectively. Typically, in this environment(excessive multipath) fading is more prevalent, and may vary from subscriber veto subscriber vendor, dependent on receiver performance. To mitigate all theseeffects, it is suggested to do the following:

7.13.1 Tune TADD/TDROP/TTDROP to force the mobile into less soft-handoff.

This would reduce the number of places where the mobile switches referPN’s, and thus make the RF path distance measurements more accurat

7.13.2 Design the frequency seam using natural topological features, such as large open tracts of land (less clutter).

This would make the effects of multipath less prevalent, and make the pmeasurements more accurate.

of 268


icts a

mus ah to

er-

an-

ibu-

hetion

Figure 3 depicts a deployment of edge-sensing, using a natural boundary. It depbridge over a river which is the intersection of two Major Trading Areas (MTA).

For sectors A and B, TADD and TDROP would be set appropriately to bias thetoward single-leg traffic channels (reduce the probability of soft handoff, and thchanging Reference PN). The river is chosen to reduce the amount of multipatmake edge sensing more reliable.

7.14 E911 techniques which may be used for hard-handoff detection.

7.14.1 Bruckert/Ghosh/ et. al. developments.

This contribution is being evaluated (in a minor way) in Release 8 of Supcell software. This evaluation covers only timing of Access probes. If wewere to permanently use this trial, it would negate the use of Probe PN rdomization (which might not have a negative impact).

Presently the final contribution is being proposed to the TIA. In this contrtion, The subscriber unit vacates the traffic channel and transmits a fixedduration burst at a pre-defined power level on the alternate frequency. Tinfrastructure equipment would employ scan receivers to determine locaof the mobile.

7.14.2 DeClerck/Harris improvements.

C Band MTA CDMA carrier domain

A Band MTA CDMA Carrier Domain

Figure 3

River

A

B

of 268


erdr-sig-ise-

The contributions of Bruckert, Ghosh, et.al. do not allow for the subscribunits’ transmit timing slew, and can create grave error. Dan DeClerck anJohn Harris are investigating the transfer of the mobiles’ timing slew infomation to the base to more accurately determine the round-trip delay of nal, and thus improve estimates of edge detection. In the DeClerck/Harrproposal, the mobile station would not vacate the traffic channel for edgdetection techniques.

of 268


of 268


8.0 Background

The following sections provide handoff background information.

of 270


of 270


8.1 CDMA Hard Handoff Problems & Solutions

Presentation to DDI 01/23/97 by Barry J. Menich

Text version of a PowerPoint document. See original PowerPoint document for the manymissing pictures

8.1.1 Hard Handoff Topics

• CDMA Basics Regarding Handoff

• The Hard Handoff Problem

• Inter-CBSC and Inter-Carrier Hard Handoff

– Intra-Carrier Hard Handoff

– Associated Problems

– Pilot Beacons

» Deployment & Method

» Optimization

» Idle-mode Handoff Problems & Solutions

• Other Techniques

– Phase Measurements

– DAHO (Database Assisted HandOff)

– Ec/Io Thresholding

– Scan Receivers

8.1.2 IS-95A Pilot Definitions

• Active Set

– Those pilot signals used as phase references for purposes of demodulating forwardtraffic channels.

• Candidate Set

– Those pilot signals displaying characteristics such that they have high probability ofbeing promoted to the Active Set.

• Neighbor Set

– Those pilot signals assigned to adjacent cells and/or sectors.

• Remaining Set

–

– PN index offsets need to be on PILOT_INC boundaries

8.1.3 Pilot Status Transitions

8.1.4 Pilot Strength Measurement Message

PSMM sent upon solicitation (demand driven) from infrastructure or according to IS-95Asection 6.6.6.2.5.2 (event driven). Requires L2 acknowledgment.

of 280


• Pilot Ec/Io Information

– Ec/Io for active and candidate set pilots.

– Ec/Io for neighbor set pilots not included.

– Ec/Io for remaining set pilots not included.

• Pilot Identification

– PN Index Offset phase measurements (whole chip resolution).

– Identity of active set pilot providing timing reference.

• Event Information

– “Keep” flag for active and candidate pilots.

– Promotion of neighbor/remaining set pilot to candidate status signified by inclusion inPSMM.

8.1.5 Pilot Scan Algorithm

• Active and candidate set pilots scanned with high priority due to increased probability ofneed to demodulate.

Neighbor set pilots scanned in between scans of all active and candidate pilots. Thus,neighbor scan interval is a function of the number of pilots in the active and candidatesets.

Remaining set pilot scanned in between scans of all neighbor set pilots. Thus, remainingset scan interval is a function of the neighbor set scan interval.

• Early scan termination if preliminary integration fails to satisfy threshold.

– Bad delay spread situation may cause fraction of early terminations to decrease, thusincreasing single pilot scan times.

8.1.6 Pilot Scanning Basics

Integration period commensurate with pilot status (ie. “active”, “candidate”, “neighbor”).More integration for active/candidate, less for neighbor/remaining.

• Filtering of active and candidate set pilot Ec/Io measurements.

– Specifications on filtering accuracy are loose.

– See Chapter 9 of IS-98.

• Qualcomm mobile station defines a “pre-candidate” status for a pilot. Ec/Io > T_ADDthreshold.

8.1.7 Pilot Scan Algorithm Implications

• Scan rate for Neighbor and Remaining set pilots is non-deterministic

– Dependent on number of active and candidate set pilots

– Dependent on number of scan “sweeps” that terminate early

• Pilot scan filter parameters for any make/model subscriber unit are unknown by infra-structure.

of 280


– Corner frequency

– Skirt

• No restriction on the number of events contained within a PSMM.

• Events are not explicitly conveyed, they must be inferred.

Neighbor-->Candidate set transitions, T_TDROP and T_COMP events are lost withPSMM rubout on reverse link (check out IS-95A section 6.6.6.2.5.2). Mobile stops tryingafter 2 re-tries.

8.1.8 The Hard Handoff Problem

• Solution for current lack of inter-CBSC SHO.

• Multi-carrier needed for system-wide capacity relief.

• “Spot” Capacity Relief.

• Inter-vendor HHO.

• PCS inter-band HHO.

• CDMA to AMPS HHO.

Not much support for HHO in IS-95A and J-STD-008. Limited to frequency agility of sub-scriber unit and CDMA channel number field in Extended Handoff Direction Message.

No analog to CDMA handoff technology available yet.

8.1.9 Multi-Carrier Handoff (“Wedding Cake” Example)

8.1.10 “Spot Capacity Relief” Example

8.1.11 Hard Handoff Algorithm

(Intra-Carrier and Pilot Beacon Techniques)

• Current algorithm for both “intra” and “inter” carrier HHO.

• Infrastructure examines contents of Pilot Strength Measurement Messages sent bysubscriber unit.

• If candidate set pilot in PSMM is

– Associated with an “external CDMA sector” (XCSECT), and

– T_COMP dB better than all active set pilots represented in PSMM, then

then Handoff to XCSECT is initiated.

• Extended Handoff Direction Message contains RF carrier identity of target.

8.1.12 Intra-Carrier Hard Handoff

• Implemented as bridge to inter-CBSC SHO.

• Inter-cell approach used.

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• Poor performance!

– High FWD FER in HHO areas both before and after HHO.

» Hysteresis scheme (ie. “T_COMP”) exacerbated Ior/Ioc problem.

– “Ping-pong” phenomena only makes audio quality worse.

» Not so bad in areas of “good” coverage.

– Susceptible to non-correlated shadowing between source and target.

» EX_HO_DIR_MSG reliability issue when source is shadowed.

– Success dependent on number of “ping-pongs”

» Always an odd number of HHOs for every seam transition.

» p(success) = (message_reliability)**X

• X = # ping-pongs

•

8.1.13 Pilot Beacons (Inter-Carrier Hard Handoff)

• Current solution for inter-CBSC handoff.

• Inter-cell handoff (CBSC boundaries don’t cross sector lines).

• Advantages:

– Allows multiple target discrimination.

– Shadowing between target and subscriber unit accounted for in target Ec/Io measure-ment.

– Many optimization “knobs” relative to intra-carrier HHO.

» Much better hysteresis control.

» Minimizes, or eliminates, “ping-pong” phenomena.

– Many in industry consider this to be the “natural solution” to the HHO problem.

– Minimizes Ior/Ioc performance problems.

» Audio quality at target much better relative to intra-carrier HHO.

• Disadvantages:

– Requires extra spectrum or extra tier of spectrum in implementation area.

» Problem for cellular operators.

– Possible gaps due to reduced beacon footprint

» May require beacon deployment on sectors facing away from CBSC seam or sourcecells.

– Requires beacon hardware and associated software and communications links/resources.

» Possible increase in beacon HW complexity with increased number of carriers.

» Needs frequency agility in idle mode.

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» LPA type (multi-tone) and capacity now a concern.

» Needs GPS signals for downlink synchronization.

– Beacons required everywhere for inter-carrier HHO

» “Spot capacity relief” becomes expensive.

8.1.14 Pilot Beacon Deployment (Inter-CBSC Handoff Example)

8.1.15 Pilot Beacon Deployment (Multi-Carrier Example)

8.1.16 Pilot Beacon Optimization

• Optimization Parameters:

– Serving cell output power

» Extend range of serving pilot(s) into seam.

– Pilot Beacon output power

» Extend range of beacon signal into seam.

– Subscriber unit T_COMP parameter (“hysteresis”)

» Slow fading allowance.

» Message integrity margin.

– Forward Power Control

» Message integrity margin.

– Neighbor Search Window

» Additional hysteresis, but must be mindful of SHO effects on current side of seam.Don’t play with this unless you have to.

If necessary, simplify to the 2-cell case (one source, one target) by turning off other bea-cons in surrounding area. Make one case work, then build from that.

Adjust (in decreasing order of desirability) T_COMP, pilot beacon power, or serving cellpower to move handoff location away from an area that’s shadowed wrt to either servingor target cells.

Use SHO thresholds and Fast Pilot Shuffling to acquire “macrodiversity” state whengoing into the seam. Some situations might have multiple shadowing angles. Multiplepaths for the Extended Handoff Direction Message increase probability of successfulmessage delivery.

8.1.17 Idle Mode Handoff Problems

• Current Pilot Beacon implementation (12/96) has introduced inefficiencies in subscriberunit System Determination at HHO seam:

Subscriber unit driving out of idle-serving system “A” will not idle HO to sys “B” (other RFcarrier) until loss of sys “A” PCH.

» Momentary lapse of service availability in idle mode.

» Algorithm not specified by J-STD-008.

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» Qualcomm algorithm is unknown.

• Search all “A” PN-space before attempt at another RF carrier?

• Pilot-based or FER-based?

– Subscriber unit may attempt System Determination on Pilot Beacon (“Pilot BeaconDwell”).

» Most typical occurrence on HHO RFLOSS.

» What is Qualcomm’s dwell time before abandoning SCH acquisition?

» Search all current carrier PN-space before attempt at another RF carrier?

• Three messages control process

– CDMA Channel List Message

– Extended Neighbor List Message

– Global Service Redirection Message

• No rigorous definitions or procedures in IS-95A or J-STD-008.

Just because Qualcomm will do something in a particular fashion doesn’t guarantee thatMotorola, Oki, Nokia, or Samsung, will do it the same way.

– Probably need to beef up IS-98 and PCS analogue.

8.1.18 Idle Mode Handoff Solutions

• Optimize inefficiency:

– Program subscriber units for limited carrier search.

– Continue to optimize current beacon signals for minimum output power such that sub-scriber dwell problem is minimized.

• Equip Pilot Beacon sites with SCH and PCH capability:

– Transmit:

8.1.18.1 CDMA Channel List Message:

• Allows mobile knowledge of paging channel RF carrier hosts.

• Need for eventual implementation of “true” multi-carrier hash.

» Global Service Redirection Message:

• Prohibits subscriber unit dwell on pilot only carriers.

• Transmit Extended Neighbor List Message from handout sites:

• Parameterize subscriber unit with alternative RF carrier to scan for Pilot, PCH, andSCH signals.

CDMA Channel List Message

• Lists all RF carriers at current cell/sector that are transmitting Paging Channels.

• Assumes all RF carriers utilizing same PN index offset as current carrier?

8.1.18.2 Extended Neighbor List Message

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• PILOT_PN (current serving site) and PILOT_INC

• Neighbor cell/sector:

– Search Priorities (not currently supported)

» Unknown how Qualcomm interprets this field.

– Neighbor Paging Channel configuration

» (000) Same num. of RF carriers, same num. or PCHs.

» (001) Same num. of RF carriers, possibly different num. of PCHS.

» (010) Different num. of RF carriers

» (011) Unknown configuration

– Neighbor RF carrier

» Qualcomm confirms they will scan other RF carrier, however we don’t know details.

– Neighbor RF Band Class (ie. PCS or cellular)

8.1.18.3 Global Service Redirection Msg.

• Direct subscriber units to other carrier or other service.

• Non-ESN specific (ie. point-to-multipoint)

• Serving cell/sector PN index offset

• Access Overload Class bit map (“ACCOLC”)

• Target RF Band Class (ie. PCS or cellular)

• Number of CDMA RF carriers

• CDMA RF carrier identities

8.1.19 Capacity With Pilot Beacons

• Question: What is the capacity degradation due to the pilot beacon implementation forinter-carrier HHO across CBSC seams?

Answer: There is none. Why would there be? Since we use another RF carrier on theother side of the seam, both FWD and REV other cell interference components (Ioc) aregreatly reduced.

8.1.20 Additional HHO Solutions Under Study/Consideration

• Edge Sensing

– Intra-cell handoff

– Techniques:

– Reverse Link Phase Measurement Technique

– Ec/Io thresholding

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– DAHO

• Inter-cell handoff

– Scan Receivers

NOTE: With the exception of DAHO, all edge sensing and scan receiver techniques arestill under scientific study. Thus, no firm plans/schedules have been adopted for theirdeployment.

8.1.20.1 Edge Sensing (Phase Technique)

• Detect subscriber unit proximity to cell “edge” or coverage “edge”.

• Seen as potential solution to “spot capacity relief” problem.

• Use reverse link short code PN phase measurement offset (from system time) as trig-ger criteria.

• Advantages:

– Allows load insensitive trigger.

– Always errors on safe side.

– Allows “grading” of incoming originations into carrier coverage at a cell (ie. use ACHphase measurement).

– Minimizes, or eliminates, need for beacon equipment.

• Disadvantages:

– Algorithm complexity increases with need for SHO at border.

– Target discrimination increases complexity and is non-deterministic. Handoff is intrinsi-cally intra-cell in nature.

– NLOS conditions may trigger false handoff detect.

8.1.20.2 Mobile Timing Basics

8.1.20.3 Phase Technique Example

8.1.21 Edge Sensing (DAHO)

• DAHO = “Database Assisted Handoff”

– Perform HHO based on identities of pilots in subscriber unit active set.

– Majority coverage by border sector pilots is HHO trigger criteria.

• Inter-CBSC HHO would require more than a single cell’s worth of overlap.

• Current CDMA to AMPS handoff technique for cellular customers:

– Customers happy with reliability, but unhappy with “wasted” CDMA Erlangs in bordercells/sectors.

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» Potential for optimization through lengthening of T_TDROP timer. This has alreadybeen tried in one market with some success.

• Handoff to underlying cell with congruent (or better) coverage.

8.1.22 DAHO Deployment

8.1.23 Edge Sensing (Ec/Io Thresholding)

Use mobile station T_DROP and T_TDROP parameters to implement handoff detect atedge of cell on single, remaining active set pilot.

– Minimal impact to current software architecture.

• Intra-cell hard handoff, continue SHO on other carrier.

• Some problems/concerns:

– Sector boundaries.

– Limited detect range (-6 dB to -13 dB).

– Increasing variance with increasing thermal noise.

– Ec/Io coverage collapse proportional to loading and inversely proportional to need!

– Needs to be optimized in unloaded case with most benign propagation in cell of inter-est (ie. worst possible handout condition).

8.1.24 Edge Sensing (Ec/Io Thresholding Example)

8.1.25 CDMA Scan Receivers

• General Idea: Use a “locating receiver” as in analog systems to determine suitability foracceptance into target cell.

• Advantages:

– ?

• Disadvantages:

– Infrastructure does not control subscriber output power (open loop). Thus, absolutemeasurement is impossible.

– Scan receiver has no a priori knowledge of reverse link noise.

– Needs reference cell PN from source cell.

– Implies Phase Technique required for source cell trigger.

– Timing “slew” suppression implies no soft handoff activity

• Interesting:

Requires moderate bandwidth connection (recurring expense) to source system whichwould be orders of magnitude greater than that required for Pilot Beacons (probably lim-ited to fault management & provisioning).

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Motorola Confidential ProprietaryMay 13, 1997Version 7.0Status: Released

CHAPTER 6 CDMA HandoffDetection and TargetSelection

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6.1 General Discussion

For CDMA systems, handoff detection processing will take place in the XC anthe MM. The XC will detect the need to handoff, perform handoff preprocesand identify events. The MM will determine the handoff type, perform target setion and perform channel allocation.

6.2 CDMA Handoff Types

IS-95 [3] allows for several types of handoff to take place. The following list elarates and summarizes each possible type of supported handoff. Some of the htypes reflect the implementation of CDMA rather than IS-95. Note that there arways two types of soft and softer handoff. One type called an “add” is used tstruct the mobile to include a new pilot in its active set. The other type call“drop” is used to instruct the mobile to exclude an old pilot from its active set.

Handoffs may be triggered by either Mobile Assisted Handoff (MAHO) or Dabase Assisted Handoff (DAHO) techniques. MAHO techniques depend on msurements made by the mobile and returned to the BTS. DAHO techniques deon information on cell configuration stored in the CBSC/BTS along with the stem’s knowledge of which cells/sectors control a particular call.

MAHO techniques may be used to trigger soft, softer and hard handoffs. DAtechniques may be used to trigger hard handoffs.

• Inter BTS, intra XC Soft Handoff: This handoff type is expected to be the hiest percentage of handoffs in CDMA systems as this type contributes to thegreatest amount of reverse channel interference reduction and capacity incrA mobile station has simultaneous connections to two or three cells and recpower control orders (for reverse link closed loop power control) from each in the soft handoff. This term will be used fairly often within the body of theSFS and can be used in a generic way.

/usr/test/adv_sys/cdma/documentation/stolen/hopc/Handover_DetectionMotorola Confidential Proprietary

System Functional Specification: Handoff and Power Control 281

Complex Handoffs


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• Intra BTS, Inter Sector, Intra XC Softer Handoff: This handoff type denotesstate where a mobile station maintains connections to multiple sectors all bat the same cellsite location.

• Inter or Intra BTS Hard Handoff: This handoff type denotes either a changeoperating frequency, a change in 1.25ms frame offset, or a handoff in whichintersection of old active set pilots with new active set pilots is the null set.

• Hard Handoff to Analog: This handoff type is used to transition a multi-modmobile station from CDMA operation to operation on an analog system.

6.3 Complex Handoffs

A complex handoff in a CDMA system is defined as a handoff instruction tomobile station which makes more than one change to the mobile’s active seexample, MAHO measurements from the mobile station may indicate that it issirable to enter into a state where new connections are supported from both thrent cellsite location (softer handoff) and from another cellsite location (handoff).

This type of handoff is not supported by the current system. The BSS will only RF: Extended Handoff Direction Messages which add or drop a single pilot fromobile station’s active set.

6.4 Database Assisted Handoff (DAHO)

This handoff detection algorithm is used to determine when to transition a mstation to another frequency band and/or air interface other than CDMA. Sincemal CDMA Mobile Assisted Handoff (MAHO) handoff detection methods cannbe used to determine a suitable target, database-stored information concernintially or fully overlapping handoff targets must be used to carry out the handoff cess.

6.5 Inter-CBSC Soft Handoff (Trunking)

Soft and softer handoffs can be performed with a cell under another CBSC by inter-CBSC soft and softer handoff procedures to connect the target CBSC chelement to the source CBSC transcoder via an inter-CBSC subrate channel.to the SSRR SFS [17] and DBCM SFS [4] for details on inter-CBSC connectiv

The method of performing inter-CBSC soft/softer handoffs via subrate chanand SCAP links between CBSCs is referred to as the trunking method, to dguish it from the A+ method, using standardized IS-634 procedures, which maimplemented in the future.

A call can be in inter-CBSC soft/softer handoff with multiple target CBSCs atsame time. A call enters into inter-CBSC soft handoff when the mobile reports able candidate pilot that points to an XCSECT (external sector data base) i

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Handoff Modes


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source CBSC, and this XCSECT has inter-CBSC soft handoffs via trunkingabled. Subsequent inter-CBSC soft and softer handoff operations may occurpilots that are in the neighbor list of a target CBSC cell. Target CBSC neighborare sent back to the source as part of the inter-CBSC soft/softer procedure. In‘remote neighbor lists’, the source checks target sectors, and non-target sectoare local to the source, for matches with candidates reported by the MS. The swill ignore matches with other neighbors in the remote neighbor lists.

The source CBSC remains in control of the call until no source handoff legs remAt this point the source determines if it should transfer control to a target CBSCa hard handoff.

In general, all procedures and requirements specified for intra-CBSC soft and handoffs apply to inter-CBSC soft and softer handoffs, unless otherwise nHowever, separate handoff execution procedures have been specified for CBSC soft handoff (trunking).

6.6 Handoff Modes

The system is required to support various “handoff modes”. The handoff modfines how the handoff detection algorithm and execution procedures operatemode defines what triggers the system to add a pilot to the mobile station activTwo modes are defined - “TAdd” and “TComp”. When operating in the TAmode, any time a pilot rises above the TAdd threshold or the TComp thresholda pilot has risen TComp × 0.5dB above any active set pilot), the system will attemto add that pilot to the mobile station’s active set via a soft or softer handoff. Woperating in the TComp mode, a pilot must rise above the TComp threshold bthe system attempts to add it to the mobile station active set.

6.7 Mobile Station Operation

It is assumed that the mobile station operates as follows (from IS-95 [3]):

• Any time a neighbor set or remaining set pilot rises above TAdd, the mobiletion sends an RF: Pilot Strength Measurement Message (PSMM) to the sysThis is referred to as a TAdd indication. The mobile station will add this pilotthe candidate set and no further TAdd indications will be sent for this pilot. Ssequent PSMMs will contain strength measurements for this pilot.

• Any time a candidate set pilot rises TComp × 0.5dB above any active set pilot,the mobile station sends a PSMM to the system. This is referred to as a TCindication. After an RF: Extended Handoff Direction Message which does ninclude the TComp pilot in the new active set, the mobile station will resendTComp indication for that pilot if the condition persists.

• The mobile station removes pilots from the candidate set as follows:1) when the pilot falls below the TDrop threshold for TTDrop seconds (thehandoff drop timer has expired)2) when the candidate set is full and the mobile station must add another piit, the mobile station will remove the pilot for which the handoff drop timer is

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Database Parameters


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• Any pilot which crosses TAdd and TComp thresholds simultaneously is treaas a TComp indication by the mobile station. The mobile station only sendsPSMM for that pilot1.

• Any time an active set pilot falls below the TDrop threshold for TTDrop sec-onds, the mobile station sends a PSMM to the system. This is referred to aTDrop indication. After an RF: Extended Handoff Direction Message whichdoes not remove the TDrop pilot from the new active set, the mobile station resend the TDrop indication for that pilot if the condition persists.

6.8 Database Parameters

The following are the database parameters which apply to handoff detection. to the DBCM SFS [4] for further information and default values.

• TAdd - Pilot Detection Threshold - The threshold above which a pilot must rin order for the MS to transmit a pilot strength measurement message. Thetem sends this parameter to the mobile station in the RF: System ParameteMessage, RF: Extended Handoff Direction Message, and the RF: In Traffic tem Parameters Message.

• TComp - Active Versus Candidate Set Comparison Threshold - The threshowhich a candidate set pilot strength must rise above an active set pilot to cathe MS to transmit a pilot strength measurement message. The system senparameter to the mobile station in the RF: System Parameters Message, Rtended Handoff Direction Message, and the RF: In Traffic System ParametMessage.

• TDrop - Pilot Drop Threshold - The threshold below which a pilot strengthmust drop in order for the MS to transmit a pilot strength measurement mesage. The system sends this parameter to the mobile station in the RF: SysParameters Message, RF: Extended Handoff Direction Message, and the RTraffic System Parameters Message.

• TTDrop - Active or Candidate Set Drop Timer - The amount of time in seconthe MS will allow an active or candidate set pilot strength to remain below tdrop threshold before action is taken to remove the pilot from the active or didate set. The system sends this parameter to the mobile station in the RFtem Parameters Message, RF: Extended Handoff Direction Message, and RF: In Traffic System Parameters Message.

• HandOffMode - Specifies to the XC which handoff mode to use. Currently twmodes are defined. TAdd mode and TComp mode. TAdd mode tells the systo add a pilot to a call as soon as it crosses the TAdd threshold. TComp motells the system to wait for a pilot to rise above the TComp threshold beforeadded to a call. This data exists in the XC database, not in the MIB.

• PilotInc - Pilot PN Sequence Offset Index Increment - The mobile station uthis field to determine how remaining set pilots should be searched. It is se

1. At least this is how Motorola mobiles are understood to operate.

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RF Measurements Used in CDMA Handoff and Power Control Detection


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the largest increment such that the pilots of the neighboring sectors are intemultiples of the increment. This data is sent to the mobile station in the RF:Neighbor List Message and the RF: Neighbor List Update Message. The Xmust use the same value as is contained in the MIB.

• NeighborList - Neighbor List - This list contains all of the neighbor sector Poffsets for the current call. This parameter is passed to the XC in both theSCAP: CDMA Update Parameters Message and the SCAP: CDMA XC Chanel Assigned Message.

• DAHO - DAHO Indicator - This parameter indicates whether a sector-carrienear a border and contains neighboring or overlapping sectors operating onother frequency and/or non-CDMA signalling scheme.

• DAHOHysTimer - DAHO Hysteresis Timer - This parameter is used to preve‘ping-pong’ handoffs between two sectors which have been marked with thDAHO flag. After a hard hand-in, origination, or termination in a border sectmajority border checks will be disabled for a period of time in seconds equathe value of this parameter.

• HandoffMethod - Handoff Method - This parameter specifies the method(none, hard, soft trunking, soft aplus) to be used to hand the call off to a seexternal to the CBSC. The scope of this parameter is per external CDMA se

• Inter-CBSC Soft Handoff Override - This parameter is used to ‘turn-off’ In-ter-CBSC soft handoffs between two MMs. It is checked by both source (inhandoff detection) and target procedures. When override is allowed, the alttive action of either no handoffs or hard handoffs is indicated (no handoffs, hno override). The scope of this parameter is per inter-CBSC trunk group.

• AnchorHoMeth - Anchor Handoff Method - this per CBSC parameter indicatthe condition upon which trigger the source MM to move a mobile in Inter-CBSC soft handoff from a source (or ‘anchor’) MM to a target MM once all tsource legs have been dropped (keep soft, on no source legs, on all legs reThe parameter can be used to keep calls in soft handoff, to execute a hardoff when there are no source legs in the call, and to execute a hard handoff all the legs are remote, i.e. no known XCSECT representations in the sourcCBSC.

6.9 RF Measurements Used in CDMA Handoff andPower Control Detection

While TDMA systems offer a plethora of RF related measurements to use in hoff detection, CDMA seems to be rather sparse in this regard. Nevertheless,appears to be some latitude for creativity in this area. The list below elaboratthe usefulness of each measurement. Specific usage of measurements can bin the procedures sections dealing with handoff and power control. Due to theticulars of the CDMA air interface, it will not be possible to use the GSM 05.08gorithm to perform handoff detection. Instead, CDMA relies on the mobile stato provide an event to the infrastructure equipment to serve notice that a threhas been crossed as well as provide MAHO measurements to assist in estabtarget suitability.

of 306

CDMA Cellsite Receive Antenna Selection


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For handoff, the main piece of data to contend with is the contents of the strength measurement message. The RF: Pilot Strength Measurement Messsent autonomously by the mobile station in response to a particular pilot crothe T_ADD, T_COMP, or T_DROP thresholds. The message contains PN pmeasurements and strengths of the pilots that the mobile station is monitoringPN phase measurements are in chip offsets relative to the zero phase pilot(i.e. relative to system time). The pilot strength measurement is actually a chnoise power ratio whose value is always less than 1.0. The mobile returns arithmic compression of this measurement equal to

where Ec is the received pilot energy per chip and I0 is the total received spectradensity (note this results in the higher the value the lower the measuremenvice-versa). Thus, pilot strengths and PN phase will be used in tandem both termine the need to handoff as well as choose appropriate targets.

On the reverse link, frame errors or frame quality depending on the frame rate tected by the MCC. For full rate and half rate air interface frames, the MCC pathe frame CRC pass/fail status and the Viterbi decoder symbol error rate to sein the uplink STRAU frames. For fourth and eighth rate frames, the MCC paonly the symbol error rate to the selector. The selector determines frame erafrom this information. A frame erasure rate (FER) can be generated in the XCa sufficient number of frames have been received to begin forming the staTypically, 1% of the frames in error will be tolerated in the system. Note that dusoft handoff, the reverse FER for a call is not necessarily determined by an indual MCC circuit. Reverse FER is determined after frame selection from all MCinvolved in the call.

On the forward link, frame errors are detected by the mobile station and reportthe base station equipment in the RF: Power Measurement Report Messagemessage contains the number of errors detected over a certain number of frThis message may be sent by the mobile station either periodically or whthreshold of bad frames has been reached. The message also contains a repolot strengths for pilots included in the current mobile station active set.

6.10 CDMA Cellsite Receive Antenna Selection

During a call, and regardless of soft or softer handoff conditions, the MCC need to check for significant reverse channel energy on a per sector basis relthe call (see FIGURE 41 on page 287). When finding a signal with significant egy that exceeds the energy being used by one of the fingers, the MCC shall dea finger to that new signal. If the signal drops below another threshold, then thger is dropped from combining. The MCC is configured to operate in a sectoromni mode. This is to prevent wasted processing time looking for signals wthere are no sector inputs.

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of 306

Maintenance Command Interaction


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6.11 Maintenance Command Interaction

Several maintenance commands are available to the craft which require handteraction. The PADD command is used to add a soft or softer connection to aPDROP performs the opposite function. HOLD maintains the current state ocall by not allowing automatic adds, drops, or external handoffs. UNHOLD clethe condition.

These commands are detailed in the CDMA CP SFS [5]. Also defined in that dment are several requirements pertaining to the execution of those commandreader is referred to that document for general requirements, including CLI inttion and resource management. This document will contain specific requiremthat impact handoff detection and target selection.

Simplified single channel MCC reverse link diagramshowing finger management detail.

(120 sector site example)

Search Processors

Demodulator

Search Processors

Demodulator

Search Processors

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FIGURE 41 Simplified Single Channel MCC Reverse Link Diagram

of 306

Handoff Detection General Requirements


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When a call is in a HOLD state, automatic handoffs will not be allowed. Soft softer handoffs will be initiated through the PADD and PDROP commands.

When a soft or softer add is specified through the PADD command, the MM initiate the indicated action. Handoff type and target selection are determineparameters in the command. See the CDMA CP SFS [5] for specific requiremNote target selection may also indicate a specific MCC timeslot (MCCce).

When a soft or softer drop is specified through the PDROP command, the MMinitiate the indicated action. Handoff type determination is specified by paramin the command. See the CDMA CP SFS [5] for specific requirements.

Should a SCAP: Handoff Recognized message arrive while a PADD or PDcommand is being processed, the message shall be discarded and not acteThe CDMA CP SFS [5] contains requirements regarding actions to be taken wPADD or PDROP is requested during handoff execution.

There are some caveats for calls that are in inter-CBSC soft handoff (trunkOnly source MM call jobs will provide a successful response to a maintencommand. HOLD and UNHOLD commands apply to inter-CBSC soft hand(trunking) when performed on the source (controlling) CBSC. The target ofcommand must be a local MCCce. PADD and PDROP may be used on the sCBSC to add or drop a local sector/MCCce. A SNAP command performed CBSC that is associated with the target side of an inter-CBSC soft handoff (tring) connection will report an error. A USE command applies only to local CBchannel elements but on the local CBSC will apply to any type of channel alltion, including inter-CBSC soft handoff (trunking) target MM allocation. Whmaintenance commands display a list of active call legs, inter-CBSC soft han(trunking) legs are displayed but are not distinguished from local legs.

Note: Upon release of the HOLD condition (i.e. the UNHOLD command is pformed) it is not required to immediately determine if a handoff to analog shoulperformed.

When an add is specified through the PADD command, a target MM call shaturn an error. Refer to requirements in the Call Processing Maintenance Commchapter of the CDMA CP SFS [5].

When an drop is specified through the PDROP command, a target MM call shaturn an error. Refer to requirements in the Call Processing Maintenance Commchapter of the CDMA CP SFS [5].

6.12 Handoff Detection General Requirements

6.13 CBSC Handoff Detection Algorithm

FIGURE 42 on page 289 shows control flow for handoff detection. The partitionof tasks within this document is not meant as an indication to an implementabut rather to facilitate understanding. The algorithm assumes that the mobile s

of 306

CBSC Handoff Detection Algorithm


valid split

henresh-ssageage isocess Mes-ddi-

is already in one of several states. The diagram also shows valid events anddecisions that are output by the detection process. The software algorithm isbetween the MM and XC subsystems.

6.13.1 Procedures

The mobile station performs MAHO procedures in accordance with IS-95. Wthe mobile station detects the occurrence of any events (such as the T_ADD thold being exceeded), it sends an RF: Pilot Strength Measurement Report Meto the base station. Upon reception of this message by the XC, the L3 messrouted to the handoff detection process. Note that the handoff detection prshall store the contents of the last 16 RF: Pilot Strength Measurement Reportsages. This information can then (if desired) be retrieved by MMI or used in ational handoff detection processing.

FIGURE 42 Handoff Detection Control Flow

MobileStation

EventDiscriminator

State Validation& Detection

Pilot StrengthPN

ValidEvents

SCAP:

Valid Measurement Events:

TAddTAdd + TCompTDrop

Valid Detection Outputs:

SHO ADDSHO DROP

Handoff Detection Process Software

PN Offset IndexDetermination

Offsets

Handoff Recognized Messages

HandoffExecution

MeasurementMessages

TargetSelection

Type andtarget info

HandoffTypeDetermination

of 306



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6.13.2 PN Offset Index Determination

The purpose of the PN Offset Index Determination subprocess is to identifybase stations used in the RF: Pilot Strength Measurement Message. The XCsystem performs this function. The identity at this point in the control flow is defined as the PN offset index used by a particular base station. The algorithplied shall be the exact algorithm that Qualcomm proposes in their Network Eneering Handbook [2]. The algorithm is reproduced here for completeness.

The mobile station computes pilot PN phase øi = (Ti + 64× PILOT_PN)mod215. Tiis the arrival time of pilot i at the mobile station (relative to the mobile’s senssystem time). øi is transmitted to the infrastructure equipment in the RF: PStrength Measurement Message.

The PN Offset Index Determination subprocess will apply the following equatioeach PN phase returned to determine the identity of the base station transmittipilot:

where the operator denotes rounding the real value “x” to the largest integervalue less than or equal tox. PilotInc is a parameter supplied to the handoff detetion process. It is assumed that all PN offset indices throughout the CDMA sywill be specified in increments of PilotInc and that PilotInc will be sufficiently lar(with respect to cell sizes) so as to avoid confusion between cell identities. that PilotPn is constrained to values between 0 and 511 and this is assured bof the way the mobile station calculates øi. Note also that if a PilotInc is used that inot 1,2,4,or 8, the last PN offset should not be used due to overlap between Pset 0 and the last PN offset.

The PN offset index determination subprocess shall also tag the pilot strengtphases returned in the RF: Pilot Strength Measurement Message as to whethpilots are currently active or candidate pilots. In addition, the keep flag assocwith each pilot and the reference PN (the pilot that the mobile station is usingauge system time) shall be perpetuated to the next subprocess. Changes to erence pilot are also noted.

Note: the XC gets the reference pilot PN directly from the RF: Pilot Strength M

surement Message.

6.13.3 Event Discrimination

The purpose of event discrimination is to decide what events have caused a mstation to send an RF: Pilot Strength Measurement Message to the infrastruequipment. This function is performed by the XC subsystem.

PilotPniφi 32 PilotInc×+( )mod215

64 PilotInc×--------------------------------------------------------------------- PilotInc×=

x

offset phase 32 PilotInc×+( )mod215

64 PilotInc×--------------------------------------------------------------------------------- PilotInc×=

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In the current system, the only valid events are: TAdd threshold crossed, TCthreshold crossed, and TDrop threshold crossed. Note also that multiple eventbe possible within each message (a complex handoff). In the current system, single event will be processed. The precedence will be TComp, TAdd, and TD

Essentially, event discrimination shall scan the list of pilots and their strengthslots in the active set can be tagged as drop if their pilot strengths are shownbelow the TDrop threshold. The keep flag within the RF: Pilot Strength Measment Message is used to differentiate between those pilot signals that have below the TDrop threshold for TTDrop seconds as opposed to those pilot sigthat have momentarily dropped below TDrop at the time the RF: Pilot StreMeasurement Message was sent by the mobile station. Thus, the first activity opart of the event discriminator is to scan the pilot strengths and their assockeep flags to determine which (if any) pilots have truly met the criteria for TDrThis is done by noting which pilot strengths have fallen below TDrop and htheir associated keep flags set to zero. Pilots not in the active set are scannedif their associated strengths have crested over the TAdd threshold, or if strengths have exceeded the TComp dB of one of these pilots. In either casevent will be a handoff.

Establishing a TAdd is done by applying the known TAdd threshold to the retumeasurements for candidate pilots. Any candidate pilot strength which is grthan or equal to the current TAdd threshold is a TAdd event.

TComp can only be applied to the strength measurements of pilots that are the active set. If a candidate set pilot has equaled or exceeded any active set pTComp × 0.5 dB, the event discriminator shall tag the candidate set pilot aTComp event.

Events which do not pass the event discrimination tests are not passed alongState Validation and Detection Process.

6.13.4 State Validation and Detection

State validation and detection determines which events are consistent with thbile stations active set state (i.e. the number of pilots in the active set). This funis performed by the XC.

The tables below shows the allowed events depending on the mobile station’s set state. There is a table for both the TAdd and TComp handoff modes Refer ble 6: "TAdd Mode State Validation Table" on page 291, and Table 7: "TCoMode State Validation Table" on page 292. Each event is listed in the column hings. The mobile station active set states are listed as row headings. Valid indthat the received event is valid for the active set state, not valid indicates thaevent is not valid and will not be processed further.

Table 6: TAdd Mode State Validation Table

TAdd Event TComp Event TDrop Event

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ciatedasso-

triesut by

After determining that there is at least one valid event, the XC will formulateSCAP: CDMA Handoff Recognized Message and set the cause field as shoTable 8: "Handoff Cause Element Coding" on page 292.

Note: It can be assumed that active set pilots can only have drop events assowith them, and that candidate set pilots can only have TAdd or TComp events ciated with them.

Note: In Table 8: "Handoff Cause Element Coding" on page 292, the blank encorrespond to situations which are not possible because they were filtered oon page 292.

1 Forward Link valid valid not valid

2 Forward Links valid valid valid

3 Forward Links valid valid valid

Table 7: TComp Mode State Validation Table

TAdd Event TComp Event TDrop Event

1 Forward Link not valid valid not valid

2 Forward Links not valid valid valid

3 Forward Links not valid valid valid

Table 8: Handoff Cause Element Coding

TAddevents

TCompevents

TComp &TAddevents

TDropevents

TAdd &TDropevents

TComp &TDropevents

TAdd &TComp &TDropevents

1 ForwardLink

SHO addone cell -TAdd

SHO addone cell -TComp





2 ForwardLinks




SHO dropone cell




3 ForwardLinks




SHO dropone cell

SHO dropone cell

SHO dropone cell

SHO dropone cell

Table 6: TAdd Mode State Validation Table

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d ind to the

ndoffed in

C.ationhich

pilot

le 9:tains

ed soheckant-

d byctive

locallists,doff

Note: The Service Option List contains the mobile service option list obtainethe Status message or the Status Response message. This list shall be senMM if it is available.

6.13.5 Handoff Type Determination

The handoff type determination subprocess is used to determine the type of hato be performed - either soft or softer and add or drop. This function is performthe MM. Its input is the SCAP: CDMA Handoff Recognized Message from the XThis message contains the latest pilot strength, active set and candidate informfrom the mobile station, as well as a cause field which specifies the event wtriggered the message to be sent.

It also contains the Keep Pilot Indicator for each active pilot. When set, that should not be considered a drop candidate.

The MM determines if a handoff add or drop is required as specified in Tab"Add/Drop Selection" on page 293. For an add case where the call already con3 forward links, a check is made to see if one of the forward links can be droppthat the candidate pilot can be added (fast pilot shuffle scenario). Before this cis done, it must be verified whether a hard handoff to CDMA or analog is warred.

If an add is determined, the candidate pilots BTS and sector are determinesearching the neighbor lists of the active pilots, and the neighbor lists of any apilots which were dropped after the last add. The neighbor lists could be in thedatabase, for active pilots local to the MM, or they could be remote neighbor backhauled from a neighbor MM, for active pilots that are inter-CBSC soft hanlegs.

a. If (candidate Ec/Io is a TComp event) or(candidate Ec/Io≥ TAdd threshold and Ec/Iois > 2 or more active pilots) drop the weakestactive pilot.

Table 9: Add/Drop Selection

TAdd orTComp EventsOnly

TDrop EventsOnly

1 ForwardLink

Attempt to addthe (strongest)candidate pilot

2 ForwardLinks

Attempt to addthe (strongest)candidate pilot

Drop the(weakest)active pilot

3 ForwardLinks

Check: dropthe (weakest)active pilot?a

Drop the(weakest)active pilot

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it isck is add

ing.

rencel can- they aresofter) areter-

t bets. It

andi-

niti-t, andlace-

ents,ventes, or

If an doesand- thenels at-

any ther theult called.

local

If the candidate pilots BTS and sector are found in a remote neighbor list, andan external BTS and sector from the neighbor MMs perspective, then a chedone to see if the BTS and sector are actually local to this MM. If yes, then theis treated as a local add. If no, this candidate is excluded from further process

Should the pilot strength be equal among two candidates for an add, the prefeis to process a local candidate, irrespective of the type of handoff that the locadidate requires. Local candidates (from a local neighbor list) get preference astypically result in local soft/softer adds. Candidates from external neighbor liststhen given preference because they typically result in subsequent icbsc soft/adds or local soft/softer adds. External candidates (from a local neighbor listgiven lowest preference as they typically result in a hard handoff or an initial inCBSC soft handoff.

If an add of a pilot is indicated, and 3 forward links are already active, it musdetermined if the candidate pilot should replace one of the currently active piloshould replace an active pilot if either of the following conditions are true:1) the candidate Ec/Io is a TComp event.2) the candidate Ec/Io is equal to or greater than the TAdd threshold, and the cdate’s Ec/Io is greater than at least two of the active pilot’s Ec/Io.If either condition is true a drop of the pilot with the weakest Ec/Io should be iated. After the drop is performed, the mobile should request another add eventhe stronger candidate pilot should “win out” and be added. This means of repment is in lieu of complex handoffs and is referred to as “fast pilot shuffling”.

Because the SCAP: Handoff Recognized Message may contain multiple evHandoff Type Determination may be performed multiple times until either an ecan be acted upon, or until all events are eliminated due to unavailable resourcthe events are not supported in the current system.

The MM must also determine if a handoff procedure should be soft or softer. add is required, and the event is associated with a pilot which is in a BTS thatnot currently have a channel assigned to the call, the MM will attempt a soft hoff add, otherwise it will attempt a softer handoff add. If a drop is required, andevent is associated with a pilot which is in a BTS that currently has two chanassigned to the call, the MM will attempt a softer handoff drop, otherwise it willtempt a soft handoff drop.

Handoff Type Determination During Call Setup

Ideally the functionality discussed above would apply to a call in progress attime from call initiation to disconnect. However, it is recognized that portions ofsystem architecture do not allow this to be easily accomplished. In particuladetection and initiation of a handoff, at the MM level during call setup, is difficto achieve. Therefore a relaxed minimum set of requirements will apply duringsetup which will provide the functionality that is currently perceived to be need

The basic functionality required is the ability to add at least one soft or softer (not inter-CBSC) leg to the call (during setup).

of 306



sageumte

det-

thisleg.etup.

pro-ld be

set- for

ell.

en-

uses.ckedCDLso

ACK

onde 292.e-

foreea

d/or par-ys-

From the MM perspective, this time is from when the channel assignment mesis sent (to the XC) to when the response is received (from the XC). At a minimthe MM shall send a SCAP: CDMA XC Handoff Direction to the XC. ImmediaMM processing of the response (SCAP: CDMA Handoff Successful) does notrimentally affect the handoff and is not a minimum requirement.

It should be noted that addition of another leg (the third), while not required attime, is next in perceived importance, followed by the dropping of an existing Hard, or inter-CBSC soft, handoffs, are not perceived as that critical during sThis is due in part to the hope that inter-CBSC seams will be carefully placed.

SCAP: Handoff Recognized messages received which cannot be immediatelycessed (e.g. hard handoff indicated, handoff already in progress, etc.) shouqueued and processed when the call transitions into a stable state.

Indications of receiving, execution of, and completion of, a handoff during call up shall be included in the CDL. See the CDMA CP SFS [5] (CDL section)more detail.

Any statistics normally pegged during handoff execution shall be pegged as w

Any additional functionality which can be added at this time, or planned for, iscouraged.

Note: Handoff execution procedures may determine other Handoff Nack caRefer to the failure scenarios in the various execution procedures. If the blohandoff is a soft/softer add or a hard handoff, the cause is stored in the LAST_HO_BLOCKED_CAUSE field. Refer to the CDMA CP SFS [5]. Refer alto the SCAP document [6] for a list of all the Handoff Nack causes.

Note: The XC subsystem does not base any processing on the Handoff N’causes.

Note: In Table 9: "Add/Drop Selection" on page 293, the blank entries correspto situations which are not possible because they were filtered out by on pagIf this situation does occur, the MM will send a SCAP Handoff N’ACK with a dtailed cause of ‘Handoff not Allowed’, and issue an exception.

Note: The XC verifies that pilots with TDrop events are in the active set, therethe MM is not explicitly required to verify this. However, it may not be a bad idto do so.

6.13.6 DAHO Handoff Detection/Determination

6.13.6.1 IntroductionThe detection algorithm is based upon determining when a multi-band anmulti-air-interface system - capable mobile has entered a sector-carrier that istially or completely overlaid by another CDMA carrier or carrier from another stem using a different air interface.

of 306



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.

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ier or

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rough

At the edge of a CDMA carrier’s coverage, border cells (or sites) exist which vide both CDMA and other carrier/signalling system coverage. Mobiles may brected to handoff to the other system upon entering majority coverage by the bcell(s). In the case of dual coverage by a system using an alternate air inteoriginations and terminations will be inhibited in the border cells by making usthe IS-95AGlobal Service Redirection Message. This message will indicate to themobile station it is to acquire the non-CDMA system and not the CDMA system

For further details on the issues surrounding DAHO handoffs, please refer to BMenich’s paper, “CDMA to AMPS Handoff Proposal”, October 6, 1994 [9].

6.13.6.2 AlgorithmDAHO handoff detection is performed in the MM.

DAHO handoff detection will occur on any of the following events:

• soft add or drop

• softer add or drop

• mobile origination

• mobile termination

• hard hand-in

Upon completion of a successful hard hand-in, mobile origination or mobile tenation to a border sector, the MM will use the DAHOHysTimer database valuinhibit all subsequent DAHO border checks (as described below) for a fixed leof time. In the case of mobile origination or termination, this will give the systtime to perform any soft or softer adds or drops which might result in the mobilmaining in that sector-carrier (majority condition not met). This helps take adtage of the capacity of the border sector-carrier on which the originationtermination occurs.

For hard hand-ins, the hysteresis timer prevents the call from “ping-ponging” to the source sector-carrier.

When one of the DAHO detection triggering events occurs, or immediately uexpiration of the hysteresis timer, the MM then checks the sector-carrier assocDAHO flag in the database to determine which active pilots (sectors) are bocells (sectors), and determines whether a hard handoff to another CDMA carrsignalling system should be attempted.

The MM determines if a DAHO handoff is required by analyzing the total numof pilots and the number of pilots that are border cells, as specified in Table"DAHO Handoff Validation Table" on page 297. In addition, if there are two actpilots and only one is a border cell, whether or not they belong to the same ceis also taken into account.

Blank entries are impossible cases. Note some entries can only be reached thprevious error or unsuccessful attempts.

of 306



theAHO

rvice

nd-

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ing

addcov- drop-ormednchorote

source

tod

If a DAHO is triggered, the MM determines the best DAHO sector, which is source sector with the strongest pilot measurement that has its associated Dflag set. This is the “Best Source Sector”.

The target selection phase is entered next.

Table 10: DAHO Handoff Validation Table

6.13.7 Inter-CBSC Soft (A+) to Hard Handoff Transition

When in inter-CBSC soft handoff and the last source leg is dropped, if the seoption allows it, a hard handoff to the target is performed.

The MM knows if a hard handoff is allowed for the call by acquiring the hard haoff flag associated with the service option the call is currently on.

Target identity information used in the A+: Handoff Required shall be the samthat used in the request to initially set up the target leg (as a soft leg).

The handoff execution process is entered next.

6.13.8 Inter-CBSC Soft (Trunking) to Anchor Handoff Transition

When in inter-CBSC soft handoff (trunking) and the last source leg is droppedMM checks if the transcoding and control of the call should be moved to a taMM. If the MM so determines, an ‘anchor handoff’ is performed by executCDMA to CDMA hard handoff procedures.

While there are no active source legs in the call, then upon each inter-CBSCand drop, the MM shall check if an anchor handoff should be performed. This ers cases where the anchor handoff is not to be performed immediately uponping the last active source leg, cases where the last source drop was perfbecause of fast pilot shuffle, and cases where it is determined to perform an ahandoff but the handoff fails and the call remains in inter-CBSC soft handoff. Nthat if all active source legs are dropped, and then subsequently one or more legs are added, an anchor handoff is not performed.

a. There is considerable debate at this point whether or not this should be a “N”. It has been decidedallow this to be changed during process initialization via an environment variable. This will be removewhen the correct setting has been determined.

1 Active Pilot 2 Active PilotsDifferent Sites

2 Active PilotsSame Site

3 Active Pilots

0 DAHO Sector-Carrier Active Pilots N N N N

1 DAHO Sector-Carrier Active Pilot Y N Ya N

2 DAHO Sector-Carrier Active Pilots Y Y Y

3 DAHO Sector-Carrier Active Pilots Y

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Target Selection


be-whilee call.cates.

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when repre- if ituresdoff.

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When in inter-CBSC soft handoff, after each local drop that was not initiatedcause of fast pilot shuffle, and after each inter-CBSC add or drop performed there are no source legs, the MM checks if there are any source legs left in thIf no, and the hard handoff flag associated with the current service option indithat the call is NOT allowed to be hard handed off, no further checking is done

If the anchor handoff method indicates that the call is to remain in inter-CBSChandoff, then no further checking is done.

If the anchor handoff method indicates that anchor handoff is to be performesoon as there are no source legs, then a target CBSC is selected and CDCDMA hard handoff procedures are initiated.

If the anchor handoff method indicates that anchor handoff is to be performed none of the target CBSC sectors supporting active call legs have a databasesentation in the source CBSC, then the MM checks if this condition is true, andis, then a target CBSC is selected and CDMA to CDMA hard handoff procedare initiated. This anchor handoff method applies hysteresis to the anchor han

6.14 Target Selection

Target selection is essentially a database driven process which results in a tarlist of targets, being selected. Please refer to the diagram below for reference dthe discussion of each handoff type.

of 306

Target Selection


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FIGURE 43 Handoff Target Selection Process

6.14.1 MAHO Target Selection

There are two types of MAHO target selection. The first results from findinneighbor with an Outward Route Index (ORI) of 0. The neighbor is defined as inal or local to the CBSC. An intra-CBSC soft or softer add will result.

The second type occurs when a non-zero ORI is found. This means the neighexternal to the CBSC, in which case further processing is required.

It is the intent to exhaust all handoff candidates, within reason, before endinsearch. The process is to find the best candidate from the MAHO list reportethe mobile until the handoff can be attempted. Failures to attempt a handoff sresult in the next best candidate being attempted. Once a handoff is attemptethe handoff execution process is entered), the MAHO list is not used again. If hoff execution was entered through the outward route traversal process, a failuexecution shall result in the next best route being attempted.

Outward Route Index List

Carrier Level

ORI Route List

.

.

.

.

.

.

CBSC Level

PNx - ORI = 0

PNy - ORI != 0

Target Info

XCSect XASectMCC MCCMNCLAC

Service Option

MNCSctr1Sctr2SiteConSIDLACMaxPLMEMTACS/AMPS

CBSC Level

NeighborAssociations

Cell ID

Cell ID

RouteNum Target

Outward Route Number Table

Carrier Level

.

.

.

.

.

.

DAHO InputsBest Source Sector

Soft/Softer Handoff(ORI = 0)

Hard Handoff

(ORI != 0)noPN - ORI != 0

MAHO InputsPN (via PSMM)

Inter-CBSC Soft Handoff

Handoff Method

of 306

Target Selection


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to the, toxter-nal-

6.14.1.1 Internal Neighbor (ORI = 0)The MAHO target selection subprocess is used to verify that the resources nsary to perform the handoff specified by the handoff type determination procesavailable, and then to start the execution procedure. This function is performthe MM. Target selection is an integral part of handoff detection as resource aability is one of the inputs into the handoff type determination process

The MAHO target selection process receives handoff types and sector informfrom the handoff type determination process. If necessary (as in the case oevents), target selection makes requests to the resource allocation function (asified in the Call Processing SFS [5]). If the requested resources are available, selection will start the determined execution procedure. If resources are unable, target selection will indicate this to the handoff type determination prowhere other handoff types or events may be processed.

The handoff execution process is entered next.

6.14.1.2 External Neighbor (ORI != 0)The handoff type determination process resulted in a pilot PN, source sectosource carrier found to be an external neighbor. The target selection processnow use that information to access the neighbor association and obtain the ased Outward Route Index.

The outward route traversal process is now entered.

6.14.2 DAHO Target Selection

Input into this process is the best target sector/carrier. The Outward Route Indsociated with the DAHO event is obtained from the database.

The outward route traversal process is now entered. Note that when enterinprocess via DAHO there is no returning to the handoff type determination pro(if no viable candidate was found) because there is no SCAP: CDMA Handoff ognized message present.

6.14.3 Outward Route Traversal

As previously discussed and shown in FIGURE 43, a configurable, table-drprocess selects the primary target and associated parameters used to initiate off request to the MSC for a hard handoff, or to a target MM for inter-CBSC handoff (trunking). Source sector, source carrier, and (if available) the sourcare inputs to this process. If a handoff is not attempted (i.e. was blocked for anson), the process allows multiple alternate targets to be specified and attempte

6.14.3.1 Route Selection

At this point an Outward Route Index has been chosen and is used to index inOutward Route (Index) List, resulting in a list of logical routes, in priority orderattempt for the handoff. Each logical route will produce a pointer to either an enal CDMA sector (XCSECT) or to an external sector operating on another sig

of 306

Target Selection


lingion.

, ando the

niti- de-ll beoff is

hard the

hard

llows.igi-

vent

ation,ther-

andoff

e list.

sible

, a setws.

vent

ling system and/or carrier. Currently, only the analog (AMPS or TACS) signalsystems are supported (XASECT). See the DBCM SFS [4] for further informat

Should the route choices be examined and no viable handoff candidate foundthis process was entered with a MAHO indication, the process shall return thandoff type determination process to look for other candidates.

6.14.3.2 Hard Handoff Route

At this point, as a result of target selection, a digital to analog route, a MAHO iated digital to digital route, or a DAHO initiated digital to digital route has beentermined that maps to a hard handoff target, and so a hard handoff wiattempted. The MM first performs some checks to make sure that a hard handallowed for the current call. If a hard handoff is allowed, all routes that are not handoff routes or are not permissible hard handoff routes are removed fromroute list. This results in a list of permissible hard handoff routes to which a handoff will be attempted.

The checks performed to make sure that a hard handoff is allowed are as foThey apply to a digital to analog hard handoff, to a MAHO initiated digital to dtal hard handoff, and to a DAHO initiated digital to digital hard handoff.

1) hard handoff is allowed for the service option in effect for the call.2) if the handoff was MAHO initiated its reported signal strength is a TComp eover each of the active pilots.3) the call is not in inter-CBSC soft handoff

If the checks do not pass, and target selection was entered with a MAHO indicthe MM discards that candidate and moves on to the next best candidate. Owise, the handoff procedure is ended. Note that this assumes that a hard hroute will not be followed by a soft handoff route in the route list.

If the checks all pass, then non-permissible routes are removed from the routThese are:

1) analog routes if the MS is not analog capable2) digital routes that do not support the service option the MS is currently on3) digital routes for which the handoff method does not indicate hard handoff

The MM then proceeds to attempt a hard handoff, using this list of permisroutes.

The net result of the preceding steps is that for each of the hard handoff typesof checks must pass before that type of hard handoff will be executed, as follo

Digital to Analog (XASECT)1) hard handoff is allowed for the service option in effect for the call.2) if the handoff was MAHO initiated its reported signal strength is a TComp eover each of the active pilots.3) the (analog) capability of the mobile is compatible with the target.4) the call is not in inter-CBSC soft handoff

of 306

Target Selection


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t be the

CB-+).

n to

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this arently

d ex-

MAHO initiated Digital to Digital (XCSECT)1) hard handoff is allowed for the service option in effect for the call.2) the target system supports the current service option assigned to the MS.3) its reported signal strength is a TComp event over each of the active pilots.4) the handoff method of the target XCSECT indicates hard handoff.5) the call is not in inter-CBSC soft handoff

DAHO initiated Digital to Digital (XCSECT)1) hard handoff is allowed for the service option in effect for the call.2) the target system supports the current service option assigned to the MS.3) the handoff method of the target XCSECT indicates hard handoff.4) the call is not in inter-CBSC soft handoff

6.14.3.3 Inter-CBSC Soft Handoff (A+) Route

If the route maps to an XCSECT with a handoff method indicating inter-CBSC handoff (A+), the MM must verify an A+ soft handoff to another system is apppriate.

The MM must verify the service option capabilities of the target system are cpatible with the service option currently in use. If the service option currently inis not compatible with the target, the handoff is not allowed.

If the call is already in inter-CBSC soft handoff (A+), the candidate cell musverified to be under the control of the other CBSC. This is done by examiningMNC and ExtCBSC of the candidate cell and comparing them to the MNC/ExtSC associated with the current portion of the call in inter-CBSC soft handoff (AIf this is true the handoff is initiated.

If the handoff is not allowed the MM shall discard that candidate and move othe next best candidate and continue as described in the previous section.

6.14.3.4 Inter-CBSC Soft (Trunking) Add, Local Trigger Route

If a MAHO event resulted in detection of a candidate pilot in a local neighbor and in determination that an inter-CBSC (trunking) add of an external target shbe attempted (Handoff Type Determination indicated ‘external target, MAHO incation’ and the route maps to an XCSECT with Handoff Method set to Soft Truing), the MM must determine if an inter-CBSC soft handoff with the target Malready exists for this call.

If an inter-CBSC soft handoff with the target MM does not already exist for call, the MM must verify that the service option capabilities of the target systemcompatible with the service option currently in use. If the service option currein use is not compatible with the target, the handoff is not allowed.

If the handoff is allowed, the MM allocates an inter-CBSC subrate channel anecutes the requirements specified in Section 4.14 of the HOPC..

of 306

General Handoff Detection and Target Selection Requirements


ined,, the

thesub-f thell try

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ndoff

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ents

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, but

If the handoff is not allowed, or an inter-CBSC subrate channel cannot be obtathe MM shall try the next route for the candidate, or if there is no next routeMM shall discard that candidate and move on to the next best candidate.

If an inter-CBSC soft handoff with the target MM already exists for this call, MM determines if this is a soft or softer add. If it is a soft add, an inter-CBSC rate channel is allocated and the requirements specified in Section 4.14 oHOPC are executed. If a subrate channel could not be allocated, the MM shathe next route for the candidate, or if there is no next route, the MM shall disthat candidate and move on to the next best candidate.

If this is a softer add, the requirements specified in Section 4.14 of the HOPCexecuted.

Inter-CBSC soft vs. inter-CBSC softer add has already been determined by HaType Determination.

6.14.4 MAHO Target Selection, Inter-CBSC (Trunking) Add, External Trigger

If a MAHO event resulted in detection of a candidate pilot in an external neighlist, and in determination that an inter-CBSC (trunking) add of an external tashould be attempted (Handoff Detection indicated ‘icbsc add - external triggthe MM must determine if an inter-CBSC soft/softer handoff with the target Malready exists for this call.

If an inter-CBSC handoff with the target MM does not already exist, the MM acates an inter-CBSC subrate channel and executes the procedures specified tion 4.14 of the HOPC. If a subrate channel cannot be allocated, the MM discard that candidate and move on to the next best candidate.

If an inter-CBSC soft handoff with the target MM already exists, and Handoff TDetermination has detected a soft add, an inter-CBSC subrate channel is alloand the requirements specified in Section 4.14 of the HOPC are executed. If arate channel could not be allocated, the MM shall discard that candidate and on to the next best candidate.

If this is a softer add, as detected by Handoff Type Determination, the requiremspecified in Section 4.14 of the HOPC are executed.

Since detection of the target on an external neighbor list means that an inter-Csoft handoff to the target CBSC either currently exists or previously existed forcall, it can be presumed that the service options are compatible.

6.15 General Handoff Detection and Target SelectionRequirements

Note: The HandOffMode is not required to be recent changeable within the XCthis would be desirable.

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Post Trial Phase 2 Issues


d as

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. It iss re- Pilot

on-as-osetionr cellntly,X, atthese diag-

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hat no

eachisions pro- indi-ppenction even1 sys-

Note: Hard handoffs initiated but blocked by the MSC are considered blockewell. Error conditions such as database errors also constitute a block.

6.16 Post Trial Phase 2 Issues

Two other events for event discrimination that might be possible are vehicle tion (or distance) and excessive forward channel FER. The former would needdriven by some criteria for handoff based on a vehicle’s location. The latter ewould probably be a function of an advanced forward channel power control arithm that does not seek to evenly distribute available LPA power.

When the XC receives what it determines to be an RF: Pilot Strength MeasureMessage containing invalid information, it discards the message. Discardingmessage at this point is a rational strategy for the CDMA trial systems. Unfonately, the mobile station will not send another RF: Pilot Strength MeasuremMessage until the relative pilot strengths change and a threshold is crossedprobably a better tactic for commercial systems to query the mobile station agards his pilot measurement status after detection of a flaw in the current RF:Strength Measurement Message.

The BBX will be equipped with an RSSI circuit to measure the signal power ctained in the 1.2288 MHz bandwidth of the frequency to which the BBX is signed. This information will be useful in determining if a mobile station can clthe reverse link on handoff. This is especially critical in a hard handoff situawhere only one target cell is specified. Under this condition, there is no othe(diversity) to enhance the probability of reception on the reverse link. Currethere is no decision on how exactly to use RSSI measurements from the BBwhat rate they should collected, or even what subsystem will be processing measurements. BBX RSSI measurements are limited to being logged by thenostic monitor for the T1 system.

RSSI can be used to determine reverse channel rise which is useful for blocki

The forward channel power control process could send a message indicating tmore power could be allocated for the current connection.

The power control execution process will generate a forward channel gain formobile connection at a base station. This gain is, of course, used in future decon forward link power control, but may also be used by the handoff detectioncess. For example, the pilot strengths reported by the mobile station may notcate handoff, but the FER experienced by the mobile would. This might habecause of the adoption of a power control algorithm that adjusts gain as a funof number of users rather than on a need basis. This type of power control, orthe use of RF: Power Report Measurement Messages is not included in the Ttem.

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Post Trial Phase 2 Issues


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8.2 Moving the Selector

The hard handoff is required to move the selector function (the software/hardware thatselects the best reverse link VCELP frames to be converted to PCM) from one CBSC toanother.

Figure 44 shows a mobile in soft handoff between CBSC-A and CBSC-B. The mobile’s

VCELP voice is routed through CBSC-B to CBSC-A’s selector function. As the mobilemoves toward CBSC-B, all of the mobile’s voice will be routed through CBSC-B as shownin Figure 45.

If the mobile keeps moving away from CBSC-A, CBSC-A does not have adequate softhandoff information to sustain the call. The selector function must be moved from CBSC-A to CBSC-B (as shown in Figure 46) which currently requires a hard handoff.

This document describes the optimum methods for performing the hard handoff.

BTS

Figure 44: Inter-CBSC Soft Handoff

BTS

BTS BTS

Inter-BSC SoftHandoff BoundaryMobile

VCELP Voice

PCM Voice

SelectorCBSC A CBSC B

MSC

Inter-CBSCTrunks

BTS

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BTS

Figure 45: Inter-CBSC Soft Handoff, Backhaul

BTS

BTS BTS

Inter-BSC SoftHandoff Boundary

MobileVCELP Voice

PCM Voice

Selector

CBSC ACBSC B

MSC

Inter-CBSCTrunks

BTS

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BTS

Figure 46: Inter-CBSC Soft Handoff, After Moving the Selector

BTS

BTS BTS

Inter-BSC SoftHandoff Boundary

MobileVCELP Voice

PCM Voice

CBSC ACBSC B

MSC

Inter-CBSCTrunks

BTS

Selector

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9.0 Release Schedule

9.1 Release 5

Pilot Beacon, intra-carrier hard handoff, CDMA to analog handoff

9.2 Release 6

DAHO, SC601 support

9.3 Release 7

inter-CBSC SHO followed by N-Way to 1-Way HHO. MS can not cross a second CBSCboundary until a HHO

9.4 Release 8

9.5 Release 9

inter-CBSC SHO followed by N-Way to N-Way HHO

Inter-CBSC SHO with the source CBSC continuously controlling the call. DAHO HHOare allowed.

least-load

reserved channels for soft handoff

9.6 Release 10

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10.0 Competition

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Features:

-Complex Handoff (swap 1for 1)-Support 6 Way Handoff-Pilot Shuffle-Pilot Dominance

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Complex Handoff (swap 1for 1)

Criteria:•Active pilots must be in a “softer”handoff call state

•Candidate must be >= to Tadd•Candidate must be associated withthe “softer pair” BTS (otherwise, addleg)

•Candidate must be > at least oneactive pilot

note: capable of only dropping a singlepilot per HDMMotorola plans to have multiple pilotdrops per HDM

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6 Way Handoff

•Limited to 3 reverse link pathPossible maximum handoffcombinations:- 3 softer pairs (6 way)- 2 softer pairs and 1 way (5 way)- 1 softer pair and 2 way soft (4 way)- 3 way soft (3 way)

•Maintains 3 way or less 87% of totalTCH time

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Pilot Dominance

•Do not add unless candidate > at leastone active pilot

•Pilot Shuffle must meet the Tcompand Tadd criteria (prevent adding apilot when active pilot is relativelystrong)

•Cannot add if reverse link path is atmaximum (3way)

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Pilot Shuffle

•Performs shuffle when in 3 wayreverse (unable to add additional leg)

•Candidate NOT associated with any ofthe active BTS (cannot meet complexhandoff criteria)

•Pilot to be “shuffled in” must meetTadd and Tcomp (otherwise, ignoresPSMM)

•No PMRO

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11.0 Summary

From Dan DeClerck’s taxonomy:

Each of the previously defined methods for hard handoff detection have varioustradeoffs.Various deployment examples are given below with the preferred method ohandoff detection.

11.1 CDMA to Analog (AMPS/NAMPS/TACS) handoff, same service provider

The preferred method would involve beacons, co-located with analog cell sites.is preferred for older mobiles (IS-95A and older), due to the large number of suscriber units which do not have the necessary software upgrades to perform valocation ranging/Edge detection or Subscriber adjacent cell scanning techniqueNewer subscriber units (IS-95B) may have functionality to scan adjacent AMPSnalling channels. This could be used for very new 800 MHz CDMA deployment

11.2 N carriers to N-1 carriers handoff (CDMA carrier handoff).

11.2.1 Extra carrier for In-building or tunnel, spot coverage.

Adjacent frequency scan by subscriber unit is the preferred method, duethe large amount of multipath and a rapidly changing Reference PN, whwould reduce the effectiveness of location ranging/ edge detection tech-niques. DAHO techniques would be difficult, since the size of the area wobe small, and DAHO requires at least two base stations overlap past theboundary of the carrier’s coverage.

11.2.2 Extra carrier for large scale changes in population density (Urban to subban/ Suburban to Rural)

Location ranging/Edge detection, DAHO or pilot beacons are preferred oother techniques, due to the inherent degradation of speech quality in thSubscriber unit adjacent frequency scanning technique. It should be notthat when using Edge Detection, the frequency seam should be chosenregard to natural topological boundaries, such as water or large open flain order to reduce the amount of multipath and or frequent changes in Rence PN (non-dominant pilot scenario). The reduction of multipath and/oelimination of a rapidly changing Reference PN by the mobile ensures amore stable environment to utilize edge sensing via PN phase measurem

11.2.3 Notes on systems that have older non-adjacent frequency scanning mo

It is possible for the older mobiles to co-exist in a system with the newermobiles. The base station may indicate the ubiquitous frequencies to themobile in theChannel List Message. The newer mobile will use theExtendedNeighbor List Messageto determine the larger set of frequencies it may usAlso, the MOBILE_P_REV field in theOrigination Message can indicatethe mobiles protocol revision level, and thus, if the mobile supports adjafrequency scanning. If the protocol revision level indicates the mobile do

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e

ro-m

of atservicensingre-

not have this capability, the mobile can be channel assigned to one of thubiquitously deployed carriers.

11.3 Intersystem seam (where the Carrier bands do not intersect)

In this scenario, it is not practical to put beacons transmitting in other service pvider’s spectrum, nor is it practical to allow the mobile to transmit in this spectrufor handoff detection(E911). DAHO is not practical, since it requires an overlap least two base stations near the edge (which is not possible, since some other provider owns the spectrum). The most practical techniques would be: Edge seif the topology of the landscape permits it, or the employment of the Adjacent Fquency scan by subscriber unit.

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12.0 Vision

12.1 Timeline

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ntd in

enda-d by

eeting

13.0 System’s Engineering Recommendations

Stolen from Rebecca MacKenzie’s May 14, 1997 memo titled “Inter-CBSC SHO DeploymeRecommmendations: System Engineering”. Sections ending with an asterisk will be coverethis document.

As promised in our discussions regarding the subject matter I have started a list of recommtions Systems Engineering would like to see implemented. Specifically, this list is developethe PrimeCo Systems Engineering Group. Some of the items where listed in your kickoff magenda but I wanted to include detail from our perspective.

13.1 Criteria for Successful Feature Deployment and Operations:

1. Must be at least as good as beacon HHO. Currently, ICBSC HHO system suc-cess rate is approximately 95%. Under controlled drives across the HHO seam,success rate is 97.5%.

2. We must have a method for tracking the performance - i.e. new CFC or PMreports that measure Anchor HO success rate.

3. Minimum CBSC outage time.

4. Minimal service interruption.

5. Application note detailing:white paper on operation of ICBSC SHOrequired database commandshardware/software requirements and implicationsmsc/cbsc/bts requirementstroubleshooting and optimization guiderf implications of N-way to 1-way Anchor HOadditional sho delay measurements with anchor cbscspecific performance measurement pm reports and cfc’sfuture enhancementsnew seam placement (traffic load placement)

6. Transitioning of inter-carrier seam supported via pilot beacons to inter-CBSCseam.

7. Fallback strategy for seam transformation.

8. Transitioning of inter-carrier seam supported via DAHO to inter-CBSC SHOseam.

9. Ability to implement 2nd carrier in hot spot areas along the seam.

13.2 New CDL format:

1. Perhaps pipe delimit the data (reduces file size).

2. Concentrate on reducing the file size.

3. Include new CFC for Anchor Handoff.

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C

4. Prior to removing any CFCs distribute the list to Systems Engineering.

13.3 Trouble-Shooting Guide:

Step by step guide to debugging of Inter-CBSC SHO features such as:

1. no audio on inter-CBSC calls

2. no inter-CBSC handoffs

3. poor audio on inter-CBSC calls

4. high failure rate of inter-CBSC Soft Handoff

5. high failure rate on inter-CBSC calls - procedural related

6. high failure rate on inter-CBSC calls - RF related

7. poor audio quality after anchor handoff

8. failures/dropped calls on anchor handoff

9. unexpected usage or blocking of BTS resources

10. increased latency of soft handoffs, adds and drops

13.4 Inter-CBSC Planning Guide:

Guide to planning the RF and infrastructure for the support the inter-CBSC feature.

1. seam placement rules*

2. MSC trunking rules

13.5 Inter-CBSC Application Note:

Information required by the customer for the deployment and maintenance of the inter-CBSSHO feature.

13.6 ATP for the Inter-CBSC SHO:

Define the acceptance test plan for the Inter-CBSC SHO feature.

13.7 Inter-CBSC Customer Presentation:

Presentation geared to customer base describing the inter-CBSC SHO feature.

1. Visuals on how the system will be laid out.general seam placement proceduresMSC layoutCBSC to MSC connects

2. Present and future release expectations.

3. How we will track performance.

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4. General Anchor HO description/function.

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14.0 Bibliography

1. Jim Marocchi’s LPA TEM

2. Dennis Schaeffer’s CDMA design tools

3. Handoff and Power Control System Functional Specification

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IIdle Handoff 155

_handoff

Documents

pilot beacon installation5

hardhandoff detection

carrier hard handoff2

carrier soft handoff2

pilot beacon3

pilot beacons daho

intercarrier hhos

intercbsc hard handoffs5