directed retry decision(ran14.0_02)

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Feature Parameter Description

Issue 02

Date 2012-07-20

HUAWEI TECHNOLOGIES CO., LTD.


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Copyright Huawei Technologies Co., Ltd. 2012. All rights reserved.

No part of this document may be reproduced or transmitted in any form or by any means without prior

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and other Huawei trademarks are trademarks of Huawei Technologies Co., Ltd.

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holders.

Notice

The purchased products, services and features are stipulated by the contract made between Huawei and

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within the purchase scope or the usage scope. Unless otherwise specified in the contract, all statements,

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The information in this document is subject to change without notice. Every effort has been made in the

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Huawei Technologies Co., Ltd.

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Directed Retry Decision Contents

Issue 02 (2012-07-20) Huawei Proprietary and Confidential

Copyright Huawei Technologies Co., Ltd.

i

Contents

1 Introduction ................................................................................................................................ 1-11.1 Scope ............................................................................................................................................ 1-11.2 Intended Audience......................................................................................................................... 1-11.3 Change History .............................................................................................................................. 1-1

2 Overview of DRD ....................................................................................................................... 2-13 RRC DRD ..................................................................................................................................... 3-1

3.1 Overview ....................................................................................................................................... 3-13.2 Procedure ...................................................................................................................................... 3-2

4 Non-Periodic DRD ..................................................................................................................... 4-14.1 Overview ....................................................................................................................................... 4-14.2 Blind-Handover-Based Non-Periodic DRD ................................................................................... 4-1

4.2.1 Inter-Frequency DRD ........................................................................................................... 4-24.2.2 Inter-Frequency DRD for Device Type Steering ................................................................... 4-44.2.3 Inter-Frequency DRD for Technological Satisfaction............................................................ 4-54.2.4 Inter-Frequency DRD for Service Steering ........................................................................... 4-64.2.5 Inter-Frequency DRD for Load Balancing ............................................................................ 4-84.2.6 Inter-RAT DRD.................................................................................................................... 4-16

4.3 Measurement-Based Non-Periodic DRD .................................................................................... 4-184.3.1 Overview ............................................................................................................................. 4-19

4.3.2 MBDR Procedure ............................................................................................................... 4-19

5 Periodic DRD .............................................................................................................................. 5-15.1 Overview ....................................................................................................................................... 5-1

5.1.1 Switches for Periodic DRD ................................................................................................... 5-15.1.2 Conditions of Periodic DRD .................................................................................................. 5-1

5.2 Periodic DRD Procedure ............................................................................................................... 5-25.2.1 Blind-Handover-based Periodic DRD ................................................................................... 5-25.2.2 Measurement-Based Periodic DRD ..................................................................................... 5-4

6 Engineering Guidelines ........................................................................................................... 6-16.1 WRFD-01061112 HSDPA DRD ..................................................................................................... 6-1

6.1.1 When to Use ......................................................................................................................... 6-16.1.2 Information to Be Collected .................................................................................................. 6-16.1.3 Feature Deployment ............................................................................................................. 6-1

6.2 WRFD-02040001 Intra System Direct Retry ................................................................................. 6-26.3 WRFD-02040002 Inter System Direct Retry ................................................................................. 6-46.4 WRFD-02040004 Traffic Steering and Load Sharing During RAB Setup ..................................... 6-66.5 WRFD-020402 Measurement Based Direct Retry ........................................................................ 6-8

7 Parameters.................................................................................................................................. 7-1


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ii

8 Counters ...................................................................................................................................... 8-19 Glossary ...................................................................................................................................... 9-110 Reference Documents ......................................................................................................... 10-1


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Directed Retry Decision 1 Introduction



1-1

1 Introduction

1.1 Scope

This document describes the Directed Retry Decision (DRD) feature. It covers both the RRC DRD andthe RAB DRD, and also provides parameter descriptions for both functions.

1.2 Intended Audience

This document is intended for:

Personnel who are familiar with WCDMA basics

Personnel who need to understand DRD

Personnel who work with Huawei products

1.3 Change History

This section provides information on the changes in different document versions.

There are two types of changes, which are defined as follows:

Feature change: refers to a change in the DRD feature.

Editorial change: refers to a change in wording or the addition of the information that was notdescribed in the earlier version.

Document Issues

The document issue is as follows:

02 (2012-07-20)

01 (2012-04-30)

Draft A (2012-02-15)

02 (2012-07-20)

This is the second commercial version of the document in RAN14.0.

Compared with 01(2012-04-30), this issue incorporates the changes described in the following table.

Change Type Change Description Parameter Change

Feature change Optimized the conditions for

determinging a non-overloaded cellin periodic DRD. For details, seesection5.2.1"Blind-Handover-based PeriodicDRD"and section5.2.2Measurement-Based PeriodicDRD."

Added the following parameter:

HRetryTargCellLoadStusInd

Editorial change The description aboutmeasurement-based non-periodicDRD (MBDR) is optimized. Fordetails, see section 4.3.1"Overview"and MBDR Target Cell Selectionin

section4.3.2 "MBDR Procedure."

None.
http://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucelldrd_hretrytargcellloadstusind.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucelldrd_hretrytargcellloadstusind.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucelldrd_hretrytargcellloadstusind.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucelldrd_hretrytargcellloadstusind.html


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1-2

Change Type Change Description Parameter Change

Added the description about how aUE selects the target cell whenconditions 1 and 2 of power-basedDRD for load balancing are met. Fordetails, see "Power-Based DRD forLoad Balancing"in section4.2.5"Inter-Frequency DRD for LoadBalancing."

None.

Added the procedures for deployingfeatures used in this document. Fordetails, see6 "EngineeringGuidelines."

None.

01 (2012-04-30)

This is the first commercial version of the document in RAN14.0.

Compared with Draft A (2012-02-15), this issue incorporates the changes described in the followingtable.

ChangeType

Change Description Parameter Change

Featurechange

Added descriptions about how todetermine the cell service priority

based on the uplink and downlinkservice channels for UEs. Fordetails, see section4.2.4Inter-Frequency DRD for ServiceSteering."

Added the following parameter:

ReservedSwitch1:RESERVED_SWITCH_1_BIT16 ReservedSwitch1:RESERVED_SWITCH_1_BIT17

Editorialchange

None. None.

Draft A (2012-02-15)

This is the first draft of the document for RAN14.0.

Compared with issue 01 (2011-04-30) of RAN13.0, this issue incorporates the changes described in thefollowing table.

ChangeType


Featurechange

Added a switch forenabling/disabling HSPA+technological satisfaction in theDRD procedure.

The added parameter is listed as follows:

HSPAPlusSatisSwitch
http://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucorrmalgoswitch_reservedswitch1.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucorrmalgoswitch_reservedswitch1.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucorrmalgoswitch_reservedswitch1.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucorrmalgoswitch_reservedswitch1.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucorrmalgoswitch_reservedswitch1.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucorrmalgoswitch_reservedswitch1.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucelldrd_hspaplussatisswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucelldrd_hspaplussatisswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucelldrd_hspaplussatisswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucorrmalgoswitch_reservedswitch1.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucorrmalgoswitch_reservedswitch1.html


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1-3

ChangeType


Editorialchange

The document description isoptimized to improve thereadability.

None.


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Directed Retry Decision 2 Overview of DRD



2-1

2 Overview of DRD

DRD is used to select a suitable cell for a UE to access. Different types of DRD can be adopted duringdifferent phases of service processing. In this way, the system capacity is maximized, and better

services are provided.

Figure 2-1 shows the different types of DRD.

Figure 2-1 Types of DRD

As show inFigure 2-1,RRC DRD is performed during RRC setup phase, which starts with RRCconnection request and ends with RRC connection setup complete.

As show inFigure 2-1,RAB DRD is performed during the RAB phase, which starts with RAB setupprocessing and ends with RAB release. There are two types of RAB DRD:

Non-periodic DRD

Non-periodic DRD is available during RAB setup, RAB modification, or DCCC channel reconfiguration.

Periodic DRD.

Periodic DRD is available after RAB setup or after the bearer scheme is changed.


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Directed Retry Decision 3 RRC DRD



3-1

3 RRC DRD

3.1 Overview

The RNC preferably selects the serving cell for the UE to access, if the serving cell does not supportSRB over HSPA when it is selected as the bearer scheme, or RRC connection setup fails in the servingcell, RRC DRD is performed and RNC instructs the UE to try to set up an RRC connection in a suitableinter-frequency neighboring cell on the same frequency band.

The causes of RRC connection setup failure contain the call admission failure in the RNC side and theRL setup failure for the resources insufficient in the NodeB side.

RRC DRD can make the UE preferably setting up RRC connection in the cell that supports the preferredtype of channel for carrying SRBs and improving RRC connection setup success rate.

The DR_ RRC_DRD_SWITCH sub-parameter of theDrSwitchparameter determines whether RRCDRD is enabled.
http://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucorrmalgoswitch_drswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucorrmalgoswitch_drswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucorrmalgoswitch_drswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucorrmalgoswitch_drswitch.html


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3-2

3.2 Procedure

Figure 3-1 The RRC DRD procedure

The RRC DRD procedure is as follows:

1. When receiving an RRC connection request, the RNC determines whether to process RRCconnection setup in the serving cell based on the preferred type of channel for carrying SRBs. Detailsare as follows:

If the serving cell supports the preferred type of channel for carrying SRBs, the RRC connection isset up in the serving cell. If the RRC connection setup fails in the serving cell, the RNC proceeds withthe operation specified in step2.

If the serving cell does not support the preferred type of channel for carrying SRBs, the RNCproceeds with the operation specified in step2.

TheSrbChlType parameter specifies the preferred type of channel for carrying SRBs,

DCH(Uplink_DCH, Downlink_DCH), HSDPA(Uplink _DCH, Downlink _HSDSCH), HSUPA(Uplink
http://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ufrcchltypepara_srbchltype.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ufrcchltypepara_srbchltype.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ufrcchltypepara_srbchltype.html


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3-3

_EDCH, Downlink _DCH), or HSPA(Uplink EDCH, Downlink_HSDSCH) can be configured as thepreferred type of channel for carrying SRBs. During RRC connection setup phase, this parameter isvalid only when theSrbChlTypeRrcEffectFlag parameter is set to true.

2. Determine whether the serving cell has an inter-frequency co-coverage neighboring cell running on

the same frequency band for blind handovers.If the serving cell has such neighboring cells and,

a. Some of these cells support the preferred type of channel for carrying SRBs, the neighboringcells that support the preferred type of channel for carrying SRBs are DRD candidate cells. In thiscase, the RNC proceeds with the operation specified in step3.

b. None of these neighboring cells supports the preferred type of channel for carrying SRBs, theRRC connection is set up in the serving cell by channel fallback. If the RRC connection setup fails, allinter-frequency neighboring cells running on the same frequency band for blind handovers are DRDcandidate cells, and the RNC proceeds with the operation specified in step3.

If the serving cell does not have such a neighboring cell, the RRC connection is set up in the servingcell by channel fallback. If the RRC connection setup fails, the algorithm goes to step 5.

Whether the neighboring cells support blind handovers is specified by the parameterBlindHoFlag.3. The RNC generates a list of inter-frequency candidate cells that support DRD according to the

following condition:

(CPICH_EcNo)RACH> DRD_EcNOnbcell

Here:

(CPICH_EcNo)RACHis the cached CPICH Ec/N0 value included in the RACH measurement report.Note that this value is for the current cell.

DRD_EcNOnbcellis the DRD threshold (specified by theDRDEcN0Threshhold parameter of celllevel) of the neighboring cell.

4. The RNC selects a target cell from the candidate cells for UE access. If the candidate cell list

contains more than one cell, the RNC selects the target cell randomly.If the UE is granted access, the RNC sends the UE an RRC Connection Setup message, containingthe information about the target cell. The UE sends the RNC an RRC Connection Setup Completemessage, indicating that UE access is complete.

If the UE is not granted access, the RNC instructs the UE to try to access another cell in thecandidate cell list until it successfully accesses a cell. If all access attempts fail, the algorithm goes tostep 5.

5. If the function of RRC redirection after DRD failure is enabled, the RNC performs RRC redirection.Otherwise, the RRC connection setup fails. For details about RRC redirection after the DRD failure,see theLoad Control Feature Parameter Description.
http://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ufrcchltypepara_srbchltyperrceffectflag.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ufrcchltypepara_srbchltyperrceffectflag.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/uinterfreqncell_blindhoflag.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/uinterfreqncell_blindhoflag.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/uinterfreqncell_blindhoflag.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/uinterfreqncell_drdecn0threshhold.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/uinterfreqncell_drdecn0threshhold.htmlhttp://localhost/var/www/apps/conversion/tmp/scratch_7/Load%20Control.htmhttp://localhost/var/www/apps/conversion/tmp/scratch_7/Load%20Control.htmhttp://localhost/var/www/apps/conversion/tmp/scratch_7/Load%20Control.htmhttp://localhost/var/www/apps/conversion/tmp/scratch_7/Load%20Control.htmhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/uinterfreqncell_drdecn0threshhold.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/uinterfreqncell_blindhoflag.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ufrcchltypepara_srbchltyperrceffectflag.html


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Directed Retry Decision 4 Non-Periodic DRD



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4 Non-Periodic DRD

This section covers the following features:

WRFD-02040001 Intra System Direct Retry

WRFD-02040002 Inter System Direct Retry

WRFD-01061112 HSDPA DRD

WRFD-020402 Measurement-based Direct Retry

4.1 Overview

Non-periodic DRD is used to select a suitable cell for UE access. It can be performed during a RABsetup, RAB modification, or DCCC channel reconfiguration.

Non-periodic DRD can be measurement-based or blind-handover-based.

Blind-handover-based non-periodic DRD is used to select a suitable cell for a UE to access accordingto device type priority, HSPA+ technological satisfaction, service priority, and cell load. It enables theUE to be served with the best technological satisfaction and implements service steering and loadbalancing.

Measurement-based non-periodic DRD (MBDR) is used to select a cell with qualifying signals for a UEto access according to the measurement result of signal quality. Compared with blind-handover-basednon-periodic DRD, MBDR increases DRD success rate when the current cell and the DRD target cellcover different areas, however, increase the UE access delay.

Blind-handover-based non-periodic DRD and measurement-based non-periodic DRD (MBDR) cannotbe used simultaneously. When MBDR is enabled, blind-handover-based non-periodic DRD isautomatically disabled. When MBDR is disabled, the following parameters determine whether to enableblind-handover-based non-periodic DRD:

For a single service, blind-handover-based non-periodic DRD is enabled by theDR_RAB_SING_DRD_SWITCH sub-parameter of theDrSwitchparameter.

For combined services, blind-handover-based non-periodic DRD is enabled by theDR_RAB_COMB_DRD_SWITCH sub-parameter of theDrSwitchparameter.

Note that if the measurement-based periodic DRD switchBasedOnMeasHRetryDRDSwitchis set toON, blind-handover-based non-periodic DRD is also controlled by theBlindDrdExceptHRetrySwitchparameter.

For example, if MBDR is disabled, the DR_RAB_SING_DRD_SWITCH sub-parameter of theDrSwitchparameter is set to ON, and theBasedOnMeasHRetryDRDSwitchparameter is set to ON, thenblind-handover-based non-periodic DRD for a single service is enabled only if the

BlindDrdExceptHRetrySwitchparameter is also set to ON.

For detailed information about blind-handover-based non-periodic DRD, see section4.2"Blind-Handover-Based Non-Periodic DRD."

For detailed information about measurement-based non-periodic DRD, see section4.3"Measurement-Based Non-Periodic DRD."

4.2 Blind-Handover-Based Non-Periodic DRD

Blind-handover-based non-periodic DRD consists of inter-frequency DRD (WRFD-02040001 IntraSystem Direct Retry) and inter-RAT DRD (WRFD-02040002 Inter System Direct Retry).

For detailed information about inter-frequency DRD, see section4.2.1 "Inter-Frequency DRD."
http://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucorrmalgoswitch_drswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucorrmalgoswitch_drswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucorrmalgoswitch_drswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucorrmalgoswitch_drswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucorrmalgoswitch_drswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucorrmalgoswitch_drswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/udrd_basedonmeashretrydrdswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/udrd_basedonmeashretrydrdswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/udrd_basedonmeashretrydrdswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellmcdrd_blinddrdexcepthretryswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellmcdrd_blinddrdexcepthretryswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellmcdrd_blinddrdexcepthretryswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucorrmalgoswitch_drswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucorrmalgoswitch_drswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucorrmalgoswitch_drswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/udrd_basedonmeashretrydrdswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/udrd_basedonmeashretrydrdswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/udrd_basedonmeashretrydrdswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellmcdrd_blinddrdexcepthretryswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellmcdrd_blinddrdexcepthretryswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellmcdrd_blinddrdexcepthretryswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/udrd_basedonmeashretrydrdswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucorrmalgoswitch_drswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellmcdrd_blinddrdexcepthretryswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/udrd_basedonmeashretrydrdswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucorrmalgoswitch_drswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucorrmalgoswitch_drswitch.html


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4-2

For detailed information about inter-RAT DRD, see section4.2.6 "Inter-RAT DRD."

4.2.1 Inter-Frequency DRD

Overview

An inter-frequency DRD procedure consists of DRD for device type steering, DRD for technologicalsatisfaction, DRD for service steering, and DRD for load balancing. The RNC performs these DRDs insequence.

Table 4-1 describes the parameters that control the corresponding DRD functions.

Table 4-1 Parameters that control the corresponding DRD functions

DRD Function Description of Control Switches

DRD for device type steering DRD for device type steering is controlled by the parameterDPGDRDSwitch.

DRD for HSPA+ technologicalsatisfaction

DRD for HSPA+ technological satisfaction is controlled by the parameterHSPAPlusSatisSwitch.

DRD for HSPA+ technological satisfaction is applicable only to UEsrequesting HSPA+ services.

DRD for service steering DRD for service steering is controlled by the parameterServiceDif fDrdSwitch

DRD for load balancing The availability of DRD for load balancing is specified by associatedparameters as follows:

The availability of power-based DRD for load balancing for DCH

services is specified by theLdbDRDSwitchDCHparameter. The availability of power-based DRD for load balancing for HSDPA

services is specified by theLdbDRDSwitchHSDPAparameter.

The availability of code-based DRD for load balancing is specified bytheCodeBalancingDrdSwitchparameter.

If one of the DRD functions is disabled, the RNC does not consider the conditions based on which thistype of DRD is performed. For example, if DRD for load balancing is disabled, the RNC does notconsider the cell load when selecting a cell based on inter-frequency DRD.

ProcedureFigure 4-1 shows the algorithm procedure of inter-frequency DRD when one of DRD functions isavailable at least, that is the UE requesting HSPA+ Service or the UE requesting non-HSPA+ Serviceand one of DRD functions (DRD for device type steering, DRD for service steering and DRD for loadbalancing) enabled at least.

Note:

DRD for HSPA+ technological satisfaction is applicable only to UEs requesting HSPA+ services.
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Figure 4-1 Inter-Frequency DRD procedure when at least one DRD function is available

As show inFigure 4-1,when one of DRD functions is available at least, the inter-frequency DRDprocedure is as follows:

1. The RNC determines the candidate cells to which blind handovers can be performed. Whether theneighboring cells support blind handovers is specified by the parameterBlindHoFlag.A candidatecell must meet the following conditions:

The candidate cell supports the requested service.

The frequency of the candidate cell is in the band supported by the UE.

The current cell meets the quality requirements of inter-frequency DRD. For details, see chapter3"RRC DRD."

The current cell is also considered as a candidate cell if it supports the requested service.
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2. The RNC selects a target cell from the candidate cells for UE access as follows:

(a) When DRD for device type steering is enabled, the RNC selects a cell with the highest devicetype steering priority as described in section4.2.2 "Inter-Frequency DRD for Device Type Steering." Ifmultiple cells have the highest device type steering priority, proceed to step (b). Otherwise, proceed

to step 3.(b) When DRD for HSPA+ technological satisfaction is enabled and the UE requests HSPA+ services.the RNC selects a cell with the highest technological satisfaction as described in section4.2.3"Inter-Frequency DRD for Technological Satisfaction." If multiple cells have the highest technologicalsatisfaction, proceed to step (c). Otherwise, proceed to step 3..

(c) when DRD for service steering is enabled, the RNC selects a cell based on DRD for servicesteering as described in section4.2.4 "Inter-Frequency DRD for Service Steering." If multiple cellshave the highest service priority, proceed to step (d). Otherwise, proceed to step 3.

(d) When DRD for load balancing is enabled, the RNC selects a cell based on DRD for loadbalancing as described in section4.2.5 Inter-Frequency DRD for Load Balancing".If multiple cellshave the lightest load, the RNC selects the target cell randomly from the candidate cells of thelightest load. Otherwise, the RNC selects the target cell randomly from the candidate cells of the

highest priority. Proceed to step 3.

When none of DRD functions is available, that is DRD for device type steering, DRD for service steering, DRD forHSPA+ technological satisfaction and DRD for load balancing are disabled, the RNC firstly instructs the UE to try toaccess the current cell. If the access fails, the RNC selects a target cell randomly from the candidate cells for the UE,proceed to step 3.

3. The call admission control (CAC) algorithm makes an admission decision based on the resourcestatus of the cell.

If the admission attempt is successful, the RNC initiates an inter-frequency blind handover to the cell.

If the admission attempt fails, the RNC removes the cell from the list of candidate cells and thenchecks whether all candidate cells have been tried.

If there is any candidate cell that has not been tried, the algorithm goes back to step 2 to try this cell.

If all candidate cells have been tried and

(a) When the service request is an HSPA one, the HSPA request is demoted to a DCH request andthe algorithm goes back to step 1 to retry admission based on R99 service requests.

(b) When the service request is a DCH one, the RNC initiates an inter-RAT DRD as described insection4.2.6 "Inter-RAT DRD."

4.2.2 Inter-Frequency DRD for Device Type Steering

Inter-Frequency DRD for device type steering belongs to the feature WRFD-020135 IntelligentInter-Carrier Layered Management, which allows the RAN to intelligently distinguish between user

equipment (UEs) and data cards in multi-carrier scenarios and set up services on different carriersbased on terminal type priority.

The availability of DRD for device type steering is specified by theDPGDRDSwitch parameter throughMML command SET UDRD(RNC level switch) or ADD UCELLDRD(cell level switch).

For details, see theIntelligent Inter-Carrier Layered Management on UEs and Data Cards FeatureParameter Description.
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4.2.3 Inter-Frequency DRD for Technological Satisfaction

Overview

Technological satisfaction refers to determining whether a candidate cell satisfies the technical

specifications for certain services, such as HSPA/HSPA+ services. DRD for technological satisfaction isused to select a suitable cell and HSPA/HSPA+ technologies for a UE based on the HSPA+ technologiessupported by the UE and the attributes of the requested service, such as the bearer channel, servicetype, and service rate.

HSPA Technological Satisfaction

For a UE requesting HSPA services, the RNC preferentially enables the UE to access an HSPA cell.

The priority order for HSPA technologies is as follows: HSDPA/HSUPA > HSDPA/DCH > DCH/HSUPA.The priority order is not controlled by switches and is always active for HSPA services.

HSPA+ Technological Satisfaction

DRD for HSPA+ technological satisfaction is applicable only to UEs requesting HSPA+ services.

DRD for HSPA+ technological satisfaction consists of the following processes:

1. The RNC determines the HSPA+ technologies that can be configured on the UE, based on theHSPA+ technologies supported by the UE and attributes of the requested service, as described intheRadio Bearers Feature Parameter Description.

2. The RNC determines the HSPA+ technological satisfaction of each candidate cell based on thepriorities of HSPA+ technologies as well as the HSPA+ technologies that can be both configured onthe UE and supported by the cell.

3. The RNC selects a suitable cell for the UE based on the priority sequence of HSPA+ technologies.The RNC also determines the HSPA+ technologies for the UE, which are the HSPA+ technologiesthat can be both configured on the UE and supported by the cell.

Priority Sequence of HSPA+ Technologies

TheHSPAPlusSatisSwitchparameter specifies whether HSPA+ technological satisfaction isconsidered in the DRD procedure. When this parameter is set to ON, HSPA+ technological satisfactionis considered in the DRD procedure for the HSPA+ services.

The technological satisfaction of a cell is determined by the HSPA+ technologies that can be bothconfigured on the UE and supported by the cell. If these HSPA+ technologies have a high priority, thecell is considered to have a high technological satisfaction.

The HSPA+ technologies comprise DC-HSDPA, enhanced layer 2 (L2), MIMO, 64QAM, DTX+DRX,

E-DPCCH Boosting, UL 16QAM, and HS-SCCH Less Operation. The priority sequences of thetechnologies in a cell supporting HSPA+ are as follows:

Table 4-2 Priority sequences of the technologies in a cell supporting HSPA+

Configuration ofMIMO64QAMorDCHSDPASwitch

Configuration ofMIMOor64QAMSwitch

Priority Sequence

DC-HSDPA MIMO DC-HSUPA+DC-HSDPA > DC-HSDPA +MIMO > DC-HSDPA(with downlink 64QAM activated in at least one cell) >MIMO+64QAM > DC-HSDPA (with downlink 16QAMactivated in at least one cell) > MIMO+DL 16QAM > DL

64QAM > DL enhanced L2 > E-DPCCH Boosting > UL
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Configuration ofMIMO64QAMorDCHSDPASwitch

Configuration ofMIMOor64QAMSwitch

Priority Sequence

16QAM > UL enhanced L2 > DTX+DRX > HS-SCCH Less

Operation

DC-HSDPA 64QAM DC-HSUPA+DC-HSDPA > DC-HSDPA+MIMO > DC-HSDPA(with downlink 64QAM activated in at least one cell) >MIMO+64QAM > DC-HSDPA (with downlink 16QAMactivated in at least one cell) > DL 64QAM > MIMO+DL16QAM > DL enhanced L2 > E-DPCCH Boosting >UL16QAM > UL enhanced L2 > DTX+DRX > HS-SCCH LessOperation

MIMO_64QAM MIMO DC-HSUPA+DC-HSDPA > DC-HSDPA+MIMO >MIMO+64QAM > DC-HSDPA (with downlink 64QAMactivated in at least one cell) > MIMO+DL 16QAM > DL64QAM > DC-HSDPA (with downlink 16QAM activated in atleast one cell) > DL enhanced L2 > E-DPCCH Boosting > UL16QAM > UL enhanced L2 > DTX+DRX > HS-SCCH LessOperation

MIMO_64QAM 64QAM DC-HSUPA+DC-HSDPA > DC-HSDPA+MIMO >MIMO+64QAM > DC-HSDPA (with downlink 64QAMactivated in at least one cell) > DL 64QAM > MIMO+DL16QAM > DC-HSDPA (with downlink 16QAM activated in atleast one cell) > DL enhanced L2 > E-DPCCH Boosting > UL16QAM > UL enhanced L2 > DTX+DRX > HS-SCCH LessOperation

One or two DC-HSDPA cells may support MIMO, depending on the configuration of the DC-HSDPA cells.Gains also vary according to whether the DC-HSDPA or MIMO technique is used. DC-HSDPA UEs havehigher throughput in low-traffic cells, whereas MIMO UEs have higher throughput in high-traffic cells.Therefore, when both DC-HSDPA and MIMO are available, Huawei introduces the DC-HSDPA andMIMO dynamic selection algorithm to determine what technique will carry incoming services accordingto the current number of HSDPA UEs and the downlink load status of the cell. This algorithm selects theoptimal technique for carrying services, thereby achieving higher throughput and improving userexperience. For details about DC-HSDPA and MIMO dynamic selection, see theMIMO Feature

Parameter Description.

4.2.4 Inter-Frequency DRD for Service Steering

Overview

This section describes the feature WRFD-02040004 Traffic Steering and Load Sharing During RABSetup.

If the UE requests a service in an area covered by multiple frequencies, the RNC selects the cell with thehighest service priority for UE access, based on the RAB service type and the service priorities in thecells.
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The availability of DRD for service steering is specified by theServiceDif fDrdSwitchparameter throughMML command SET UDRD(RNC level switch) or ADD UCELLDRD(cell level switch).

Inter frequency DRD for service steering can also be called inter-frequency DRD for traffic steering.

Cell Service PrioritiesA cell service priority is a service-specific priority for a cell among cells in the same coverage area. Cellservice priorities help achieve traffic absorption in a hierarchical way.

The service priorities of a cell are set as follows:

1. Run the ADD USPGcommand to add a service priority group, which is identified by SpgId.Thisgroup includes the service priorities of a cell.

2. Run the ADD UCELLSETUP, MOD UCELLSETUP, or ADD UCELLQUICKSETUP command toassign the SPG identity to the cell, that is, to set the service priorities for the cell.

The SPG to which a cell belongs is independent of DRD for service steering. For example, if the priority of a service is setto 0 in an SPG, this service cannot be established in the cells belonging to the SPG, regardless of whether DRD for servicesteering is activated or not.

When selecting a target cell for RAB processing, the RNC selects a cell with a high priority, that is, a cellthat has a low service priority value.

The service priority groups given in the following table are defined on the RNC.

Cell SPGIdentity

ServicePriority of R99RT Service

ServicePriority of R99NRT Service

ServicePriority ofHSDPAService

Service Priorityof HSUPAService

Service Priority ofExtension Services

A 1 2 1 1 1 0

B 2 1 2 0 0 0

As shown in the following figure, cell B has a higher service priority for the R99 RT service than cell A. Ifthe UE requests an R99 RT service in cell A, the RNC preferably selects cell B for the UE to access.
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Figure 4-2 Example of DRD for service steering

If the requested service is a combined service, the RAB with the highest priority is used when a cell is selected for RABprocessing. In addition, the target cell must support all of the necessary services. For details about the priority of a RAB,see theLoad Control Feature Parameter Description.

The service priority of a DC-HSDPA /DC-HSUPA cell group is determined by the highest service priorityof the two cells.

The RNC determines the cell service priority based on the uplink and downlink service channels of theUE. The UE selects a cell with a higher service priority to access.

For UEs whose uplink and downlink services are both carried on HSPA channels:

WhenReservedSwitch1:RESERVED_SWITCH_1_BIT16 of the SET UCORRMALGOSWITCHcommand is set to 1, the RNC first considers the HSDPA service priority of candidate cells whendetermining the cell service priority. If the HSDPA service priority of candidate cells is the same, theRNC considers the HSUPA service priority.

WhenReservedSwitch1:RESERVED_SWITCH_1_BIT16 of the SET UCORRMALGOSWITCHcommand is set to 0, the RNC first considers the HSUPA service priority of candidate cells whendetermining the cell service priority. If the HSUPA service priority of candidate cells is the same, theRNC considers the HSDPA service priority.

For UEs whose either uplink or downlink services (but not both) are carried on HSPA channels:

WhenReservedSwitch1:RESERVED_SWITCH_1_BIT17 of the SET UCORRMALGOSWITCHcommand is set to 1, the RNC only considers the HSUPA or HSDPA service priority (but not both)when determining the cell service priority.

WhenReservedSwitch1:RESERVED_SWITCH_1_BIT17 of the SET UCORRMALGOSWITCHcommand is set to 0, the RNC first considers the HSUPA or HSDPA service priority (but not both)when determining the cell service priority. If the HSUPA or HSDPA service priority of candidate cells isthe same, the RNC considers the R99 service priority. Among R99 services, RT services and NRTservices are assigned different priorities.

4.2.5 Inter-Frequency DRD for Load Balancing

This section describes the feature WRFD-02040004 Traffic Steering and Load Sharing During RAB

Setup.
http://localhost/var/www/apps/conversion/tmp/scratch_7/Load%20Control.htmhttp://localhost/var/www/apps/conversion/tmp/scratch_7/Load%20Control.htmhttp://localhost/var/www/apps/conversion/tmp/scratch_7/Load%20Control.htmhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucorrmalgoswitch_reservedswitch1.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucorrmalgoswitch_reservedswitch1.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucorrmalgoswitch_reservedswitch1.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucorrmalgoswitch_reservedswitch1.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucorrmalgoswitch_reservedswitch1.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucorrmalgoswitch_reservedswitch1.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucorrmalgoswitch_reservedswitch1.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucorrmalgoswitch_reservedswitch1.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucorrmalgoswitch_reservedswitch1.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucorrmalgoswitch_reservedswitch1.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucorrmalgoswitch_reservedswitch1.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucorrmalgoswitch_reservedswitch1.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucorrmalgoswitch_reservedswitch1.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucorrmalgoswitch_reservedswitch1.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucorrmalgoswitch_reservedswitch1.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucorrmalgoswitch_reservedswitch1.htmlhttp://localhost/var/www/apps/conversion/tmp/scratch_7/Load%20Control.htm


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If the UE requests a service setup or channel reconfiguration in an area covered by multiple frequencies,the RNC sets up the service on a carrier with a light load to balance out the load among the cells on thedifferent frequencies.

Inter-frequency DRD for load balancing also can be called inter-frequency DRD for load sharing.

"Inter-frequency DRD for load balancing" is called "DRD for load balancing" for short in this section.

This section describes the procedure for performing DRD for load balancing when DRD for service steering is disabled.

Overview

DRD for load balancing concerns two resources: power and code.

The availability of DRD for load balancing is specified by associated parameters as follows:

The availability of power-based DRD for load balancing for DCH services is specified by theLdbDRDSwitchDCHparameter.

The availability of power-based DRD for load balancing for HSDPA services is specified by theLdbDRDSwitchHSDPA parameter.

The availability of code-based DRD for load balancing is specified by theCodeBalancingDrdSwitchparameter.

It is recommended that only power-based DRD for load balancing or code-based DRD for load balancingbe activated. When both are activated, power-based DRD for load balancing takes precedence overcode-based DRD for load balancing.

Code-based DRD for load balancing is applicable to only R99 services because HSDPA services usereserved codes.

Power-Based DRD for Load Balancing

For Non-DC-HSDPA/ Non-DC-HSUPA Services

The following two algorithms are available for power-based load balancing. The algorithm used isspecified by theLdbDRDchoiceparameter.

Algorithm 1: DRD for load balancing is performed according to the cell measurement values for the DLnon-HSDPA power and DL HS-DSCH GBP.

ThePowLoadDRDOptSwitchparameter has been added to specify whether DRD for load balancingconsiders the load caused by non-HSPA services and the GBP load caused by HSDPA services.

When thePowLoadDRDOptSwitchparameter is set to OFF,

The RNC sets up DCH services on a carrier with a light non-HSDPA power load to achieve load

balancing among the cells at different frequencies.The RNC sets up the HSDPA services on a carrier with a light HS-DSCH GBP load to achieve loadbalancing among the cells at different frequencies.

When thePowLoadDRDOptSwitchparameter is set to ON,

The RNC sets up DCH or HSDPA services on a carrier with a light (non-HSDPA power + HS-DSCHGBP) load to achieve load balancing among the cells at different frequencies.

Algorithm 2: DRD for load balancing is performed according to the DCH equivalent number of users(ENU) and HSDPA user number.

The RNC sets up DCH services on a carrier with a light DCH ENU load to achieve load balancingamong the cells at different frequencies.

The RNC sets up HSDPA services on a carrier with a light HSDPA user load to achieve loadbalancing among the cells at different frequencies.
http://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucelldrd_ldbdrdswitchdch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucelldrd_ldbdrdswitchdch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucelldrd_ldbdrdswitchhsdpa.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucelldrd_ldbdrdswitchhsdpa.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucelldrd_codebalancingdrdswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucelldrd_codebalancingdrdswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucelldrd_codebalancingdrdswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucelldrd_ldbdrdchoice.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucelldrd_ldbdrdchoice.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucelldrd_ldbdrdchoice.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/udrd_powloaddrdoptswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/udrd_powloaddrdoptswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/udrd_powloaddrdoptswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/udrd_powloaddrdoptswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/udrd_powloaddrdoptswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/udrd_powloaddrdoptswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/udrd_powloaddrdoptswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/udrd_powloaddrdoptswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/udrd_powloaddrdoptswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/udrd_powloaddrdoptswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/udrd_powloaddrdoptswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/udrd_powloaddrdoptswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucelldrd_ldbdrdchoice.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucelldrd_codebalancingdrdswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucelldrd_ldbdrdswitchhsdpa.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucelldrd_ldbdrdswitchdch.html


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Figure 4-3 shows the procedure for power-based DRD for load balancing.

Figure 4-3 Procedure for power-based DRD for load balancing

The procedure for power-based DRD for load balancing is as follows:

1. The RNC determines the candidate cells.

A candidate cell must meet the following conditions: (Note that target cell selection is also based onthe resources of the DC-HSDPA cell group when the cell group is involved).

The candidate cell supports blind handover. Whether the neighboring cells support blind handovers isspecified by the parameterBlindHoFlag.

The candidate cell supports the requested service.

The frequency of the candidate cell is in the band supported by the UE.

The current cell meets the quality requirements of inter-frequency DRD. For details, see chapter3"RRC DRD."

The current cell is also considered as a candidate cell if it supports the requested service.

2. If the current cell is a candidate cell, the RNC proceeds to step 3. Otherwise, the RNC selects the cellwith lightest load from the candidate cell list and goes to step 5.
http://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/uinterfreqncell_blindhoflag.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/uinterfreqncell_blindhoflag.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/uinterfreqncell_blindhoflag.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/uinterfreqncell_blindhoflag.html


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3. The RNC determines whether the current cell meets the following condition (condition 1). If thecurrent cell meets condition 1, the load margin of the current cell is large and the UE accesses thecurrent cell without attempting to access an inter-frequency neighboring cell.

For algorithm 1, condition 1 is as follows:

a. For DCH servicesWhen thePowLoadDRDOptSwitchparameter is set to OFF,

(ThdAMR,cutcell- Pnon-H,cutcell) > Thdnon-H


(Thdtotal,cutcell- Pnon-H,cutcell-PGBP,cutcell) > Thdnon-H

Here,

ThdAMR,cutcellis specified byDlConvAMRThdof the current cell.

Pnon-H,cutcellis the ratio of the non-HSDPA power load of the current cell to the total downlink load.

Thdnon-His specified byLdbDRDLoadRemainThdDCH.Thdtotal.cutcellis the total power load thresholdDlCellTotalThd.

b. For HSDPA services


(Thdtotal,cutcell- PGBP,cutcell) > ThdH


(Thdtotal,cutcell- Pnon-H,cutcell- PGBP,cutcell) > ThdH

Here,

Thdtotal,cutcellis specified byDlCellTotalThdof the current cell.

PGBP,cutcellis the ratio of the HS-DSCH GBP load of the current cell to the total downlink load.

ThdHis specified byLdbDRDLoadRemainThdHSDPA .


a. For DCH services

(ThdAMR,cutcell- PD-enu,cutcell) > Thdnon-H

Here, PD-enu,cutcellis the ratio of the DCH ENU load of the current cell to the total downlink ENU load.The total equivalent user number corresponding to the total downlink load is specified byDlTotalEqUserNum.

b. For HSDPA services

(ThdH-ue,cutcell-PH-ue,cutcell) / ThdH-ue,cutcell> ThdHHere,

ThdH-ue,cutcellis specified byMaxHsdpaUserNumof the current cell.

PH-ue,cutcellis the total number of HSDPA users of the current cell.

If condition 1 is met, go to step 5. If condition 1 is not met, go to step 4.

4. The RNC selects a target cell for theUE to access.

The RNC determines whether any inter-frequency neighboring cell meets the following condition(condition 2). If an inter-frequency neighboring cell meets condition 2, the load margin of thisinter-frequency neighboring cell is large and the UE attempts to access this inter-frequencyneighboring cell.

http://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/udrd_powloaddrdoptswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/udrd_powloaddrdoptswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/udrd_powloaddrdoptswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/udrd_powloaddrdoptswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/udrd_powloaddrdoptswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/udrd_powloaddrdoptswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellcac_dlconvamrthd.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellcac_dlconvamrthd.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellcac_dlconvamrthd.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucelldrd_ldbdrdloadremainthddch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucelldrd_ldbdrdloadremainthddch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucelldrd_ldbdrdloadremainthddch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellcac_dlcelltotalthd.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellcac_dlcelltotalthd.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellcac_dlcelltotalthd.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/udrd_powloaddrdoptswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/udrd_powloaddrdoptswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/udrd_powloaddrdoptswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/udrd_powloaddrdoptswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/udrd_powloaddrdoptswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/udrd_powloaddrdoptswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellcac_dlcelltotalthd.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellcac_dlcelltotalthd.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellcac_dlcelltotalthd.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucelldrd_ldbdrdloadremainthdhsdpa.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucelldrd_ldbdrdloadremainthdhsdpa.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucelldrd_ldbdrdloadremainthdhsdpa.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellcac_dltotalequsernum.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellcac_dltotalequsernum.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellcac_maxhsdpausernum.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellcac_maxhsdpausernum.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellcac_maxhsdpausernum.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellcac_maxhsdpausernum.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellcac_dltotalequsernum.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucelldrd_ldbdrdloadremainthdhsdpa.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellcac_dlcelltotalthd.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/udrd_powloaddrdoptswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/udrd_powloaddrdoptswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellcac_dlcelltotalthd.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucelldrd_ldbdrdloadremainthddch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellcac_dlconvamrthd.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/udrd_powloaddrdoptswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/udrd_powloaddrdoptswitch.html


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For DCH services


(ThdAMR,nbcell- Pnon-H,nbcell) - (ThdAMR,cutcell- Pnon-H,cutcell) > ThdD,loadoffset

(Thdtotal,cutcell- Pload,cutcell) - (Thdtotal,nbcell- Pload,nbcell) < Thdtotal,loadoffset


(Thdtotal, nbcell- Pnon-H, nbcell- PGBP, nbcell) - (Thdtotal,cutcell- Pnon-H,cutcell- PGBP,cutcell) > ThdD,loadoffset

Here,

ThdAMR,nbcellis specified byDlConvAMRThdof the neighboring cell.

Pnon-H,nbcellis the ratio of the non-HSDPA power load of the neighboring cell to the total downlink load.

ThdD,loadoffsetis specified byLdbDRDOffsetDCH.

Pload,cutcellis the ratio of the sum of the non-HSDPA power and the HS-DSCH GBP load of the currentcell to the total downlink load. The HS-DSCH GBP load of the current cell is the sum of the HSDPAservice GBPs in the current cell. GBP for a HSDPA service is the minimum power required to ensurethe GBR on HS-DSCH. If there is no data transmitting for a HSDPA service, the GBP for this HSDPAservice is zero.

Thdtotal,nbcell is specified byDlCellTotalThdof the neighboring cell.

Pload,nbcellis the ratio of the sum of the non-HSDPA power and the GBP load of the neighboring cell tothe total downlink load.

Thdtotal,loadoffset is specified byLdbDRDTotalPwrProThd.

For HSDPA services


(Thdtotal,nbcell- PGBP,nbcell) - (Thdtotal,cutcell- PGBP,cutcell)> ThdH,loadoffset

(Thdtotal,cutcell- Pload,cutcell

) - (Thdtotal,nbcell- Pload,nbcell

) ThdH,loadoffset

Here,

PGBP,nbcellis the HS-DSCH GBP load of the neighboring cell.

ThdH,loadoffsetis specified byLdbDRDOffsetHSDPA .


For DCH services

(ThdAMR,nbcell- PD-enu,nbcell) - (ThdAMR,cutcell- PD-enu,cutcell) > ThdD,loadoffset

Here, PD-enu,nbcellis the ratio of the DCH ENU load of the neighboring cell to the total downlink ENUload.

For HSDPA services

(ThdH-ue,nbcell- PH-ue,nbcell) / ThdH-ue,nbcell- (ThdH-ue,cutcell- PH-ue,cutcell) / ThdH-ue,cutcell> ThdH,loadoffset

Here,

ThdH-ue,nbcellis specified byMaxHsdpaUserNumof the neighboring cell.

PH-ue,nbcellis the total number of HSDPA users of the neighboring cell.

Then, the RNC selects the target cell as follows:

If there is only one inter-frequency neighboring cell that meets condition 2, the RNC selects this cell asthe target cell. If there are multiple such cells:

For DCH services
http://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/udrd_powloaddrdoptswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/udrd_powloaddrdoptswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/udrd_powloaddrdoptswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/udrd_powloaddrdoptswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/udrd_powloaddrdoptswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/udrd_powloaddrdoptswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellcac_dlconvamrthd.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellcac_dlconvamrthd.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellcac_dlconvamrthd.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/udrd_ldbdrdoffsetdch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/udrd_ldbdrdoffsetdch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/udrd_ldbdrdoffsetdch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellcac_dlcelltotalthd.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellcac_dlcelltotalthd.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellcac_dlcelltotalthd.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/udrd_ldbdrdtotalpwrprothd.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/udrd_ldbdrdtotalpwrprothd.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/udrd_ldbdrdtotalpwrprothd.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/udrd_powloaddrdoptswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/udrd_powloaddrdoptswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/udrd_powloaddrdoptswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/udrd_powloaddrdoptswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/udrd_powloaddrdoptswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/udrd_powloaddrdoptswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/udrd_ldbdrdoffsethsdpa.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/udrd_ldbdrdoffsethsdpa.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/udrd_ldbdrdoffsethsdpa.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellcac_maxhsdpausernum.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellcac_maxhsdpausernum.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellcac_maxhsdpausernum.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellcac_maxhsdpausernum.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/udrd_ldbdrdoffsethsdpa.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/udrd_powloaddrdoptswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/udrd_powloaddrdoptswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/udrd_ldbdrdtotalpwrprothd.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellcac_dlcelltotalthd.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/udrd_ldbdrdoffsetdch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellcac_dlconvamrthd.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/udrd_powloaddrdoptswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/udrd_powloaddrdoptswitch.html


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a. If algorithm 1 is used,

When thePowLoadDRDOptSwitchparameter is set to OFF, the RNC selects the cell with thelightest non-HSDPA load as the target cell.

When thePowLoadDRDOptSwitchparameter is set to ON, the RNC sets up DCH services on a

carrier with a light (non-HSDPA power + HS-DSCH GBP) load to achieve load balancing among thecells at different frequencies.

b. If algorithm 2 is used, the RNC selects the cell with the lightest DCH ENU load as the target cell.

For HSDPA services

a. If algorithm 1 is used,

When thePowLoadDRDOptSwitchparameter is set to OFF, the RNC selects the cell with thelightest load of HS-DSCH required power as the target cell.

When thePowLoadDRDOptSwitchparameter is set to ON, the RNC sets up HSDPA services on acarrier with a light (non-HSDPA power + HS-DSCH GBP) load to achieve load balancing among thecells at different frequencies.

b. If algorithm 2 is used, the RNC selects the cell with the lightest HSDPA user load as the targetcell.

If there no cell meets condition 2, the RNC selects the current cell as the target cell.

5. The CAC algorithm makes an admission decision based on the status of the target cell.

If the admission attempt is successful, the RNC accepts the service request.

If the admission attempt fails, the RNC checks whether admission decisions have been made for allthe candidate inter-frequency neighboring cells.

If there is any candidate cell that has not been tried, the algorithm goes back to step 2 to try this cell.

If admission decisions have been made for all the candidate cells:

a. When the service request is an HSPA one, the HSPA request falls back to a DCH one. Then, the

algorithm goes back to step 1to retry admission based on R99 service request.b. When the service request is a DCH one, the RNC initiates an inter-RAT DRD.

For DC-HSDPA Services

If multiple DC-HSDPA cell groups are available after DRD for technological satisfaction and DRD forservice steering, the RNC performs DRD for load balancing.

DRD for load balancing for DC-HSDPA services is similar to that of non-DC-HSDPA services. Thedifference is that the former considers cell groups (not individual cells), calculates their load factors, andfinally selects a suitable cell group.

After the RNC selects a suitable DC-HSDPA cell group, it determines the primary cell based on thetechnological satisfaction and service priorities of the two cells. If the two cells have the same

technological satisfaction and service priority, the RNC performs the following operations:

If the uplink load balancing switchULLdbDRDSwitchDcHSDPA is turned off, the RNC selects eitherof the two cells as the primary cell.

If this switch is turned on, the RNC determines the primary cell based on uplink load balancing.

The uplink load balancing mechanism is introduced to prevent RNC from selecting the same cell as theprimary cell for multiple UEs requesting DC-HSDPA services.

Uplink load balancing between the two cells is performed based on the uplink ENU.

The procedure for uplink power-based DRD for load balancing is as follows:

6. If the current cell is not in the target DC-HSDPA cell group, the RNC selects a primary cell with alighter load.
http://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/udrd_powloaddrdoptswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/udrd_powloaddrdoptswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/udrd_powloaddrdoptswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/udrd_powloaddrdoptswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/udrd_powloaddrdoptswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/udrd_powloaddrdoptswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/udrd_powloaddrdoptswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/udrd_powloaddrdoptswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/udrd_powloaddrdoptswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/udrd_powloaddrdoptswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/udrd_powloaddrdoptswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/udrd_powloaddrdoptswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucelldrd_ulldbdrdswitchdchsdpa.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucelldrd_ulldbdrdswitchdchsdpa.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucelldrd_ulldbdrdswitchdchsdpa.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucelldrd_ulldbdrdswitchdchsdpa.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/udrd_powloaddrdoptswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/udrd_powloaddrdoptswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/udrd_powloaddrdoptswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/udrd_powloaddrdoptswitch.html


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7. If the current cell is in the target DC-HSDPA cell group, the RNC checks whether the UL load marginof the current cell is higher than the value ofULLdbDRDLoadRemainThdDCHSDPA:

If the margin is higher, the RNC selects the current cell as the primary cell.

If the margin is not higher, the RNC calculates the difference between the UL load margin of the target

cell and that of the current cell. Then,If the difference is greater than the value ofULLdbDRDOffsetDcHSDPA ,the RNC selects the targetcell as the primary cell.

Otherwise, the RNC selects the current cell as the primary cell.

For DC-HSUPA Services

The RNC determines only the primary carrier in the DC-HSUPA DRD procedure. The secondary carrieris automatically determined after the primary carrier is determined. The configuration of the primaryDC-HSUPA carrier is the same as that of the primary DC-HSDPA carrier. Therefore, the DRD proceduresof DC-HSUPA and DC-HSDPA are the same.

Code-Based DRD for Load Balancing

Code-based DRD for load balancing is similar to power-based DRD for load balancing. The difference isthat the RNC considers code resources when selecting a target cell.

The following figure shows the procedure for code-based DRD for load balancing.
http://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucelldrd_ulldbdrdloadremainthddchsdpa.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucelldrd_ulldbdrdloadremainthddchsdpa.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucelldrd_ulldbdrdloadremainthddchsdpa.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/udrd_ulldbdrdoffsetdchsdpa.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/udrd_ulldbdrdoffsetdchsdpa.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/udrd_ulldbdrdoffsetdchsdpa.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/udrd_ulldbdrdoffsetdchsdpa.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucelldrd_ulldbdrdloadremainthddchsdpa.html


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Figure 4-4 Procedure for code-based DRD for load balancing

The procedure is as follows:

1. The RNC determines whether the minimum remaining SF of the current cell is smaller than theminimum SF threshold of DRD for code balancing (CodeBalancingDrdMinSFThd).

If the minimum remaining SF is smaller than this threshold, the RNC requests access to the currentcell.

If the minimum remaining SF is not smaller than this threshold, the RNC goes to the next step.

For handovers, the minimum remaining SF indicates the minimum spreading factor available in acell. For other services, the minimum remaining SF indicates the minimum spreading factoravailable in a cell based on the assumption that another handover reservation code (set by theDlHoCeCodeResvSfparameter) is allocated.

Calculating the minimum remaining SF considers HSDPA dynamic code allocation. The minimumcode allocated to an HSDPA user is considered as occupied and the other allocated dynamic codesare considered as vacant when the minimum remaining SF is calculated. For details about HSDPAdynamic code allocation, see theHSDPA Feature Parameter Description.
http://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucelldrd_codebalancingdrdminsfthd.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucelldrd_codebalancingdrdminsfthd.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucelldrd_codebalancingdrdminsfthd.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellcac_dlhocecoderesvsf.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellcac_dlhocecoderesvsf.htmlhttp://localhost/var/www/apps/conversion/tmp/scratch_7/HSDPA.htmhttp://localhost/var/www/apps/conversion/tmp/scratch_7/HSDPA.htmhttp://localhost/var/www/apps/conversion/tmp/scratch_7/HSDPA.htmhttp://localhost/var/www/apps/conversion/tmp/scratch_7/HSDPA.htmhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucellcac_dlhocecoderesvsf.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucelldrd_codebalancingdrdminsfthd.html


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2. The RNC determines whether the code load of the current cell is lower than the code occupation ratethreshold of DRD for code balancing (CodeBalancingDrdCodeRateThd).

If the code load is lower than this threshold, the service tries to access the current cell.

If the code load is higher than or equal to this threshold, the RNC selects the cell as follows:

If the minimum SF supported by the cell with the lightest code load is the same as that supported bythe current cell, and the difference between the code resource occupancies of the two is greater thanor equal to the value ofDeltaCodeOccupiedRate,the RNC selects the cell with the lightest codeload as the target cell. Otherwise, the RNC selects the current cell as the target cell.

If the minimum SF supported by the cell with the lightest code load is smaller than the minimum SFsupported by the current cell, the RNC selects the cell with the lightest code load as the target cell.

4.2.6 Inter-RAT DRD

Overview

When all admission attempts for inter-frequency DRD during RAB processing fail, the RNC determines

whether to initiate an inter-RAT DRD.

The DR_INTER_RAT_DRD_SWITCH sub-parameter of theDrSwitchparameter determines whetherRRC DRD is enabled.

Procedure

The following figure shows the inter-RAT DRD procedure.

Figure 4-5 Inter-RAT DRD procedure

The inter-RAT DRD procedure is as follows:
http://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucelldrd_codebalancingdrdcoderatethd.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucelldrd_codebalancingdrdcoderatethd.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucelldrd_codebalancingdrdcoderatethd.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/udrd_deltacodeoccupiedrate.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/udrd_deltacodeoccupiedrate.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/udrd_deltacodeoccupiedrate.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucorrmalgoswitch_drswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucorrmalgoswitch_drswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucorrmalgoswitch_drswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucorrmalgoswitch_drswitch.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/udrd_deltacodeoccupiedrate.htmlhttp://localhost/var/www/apps/conversion/tmp/RNCParaHtml/mbsc/m-para/ucelldrd_codebalancingdrdcoderatethd.html


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1. If the current cell is configured with any neighboring GSM cell suitable for blind handover and if the"service handover" IE in the RAB assignment signaling assigned by the CN is set to "handover toGSM should be performed" or "handover to GSM should not be performed", then the RNC performsstep 2. Otherwise, the service request undergoes preemption and queuing as described in theLoadControl Feature Parameter Description.

Whether the neighboring cells support blind handovers is specified by the parameterBlindHoFlag.

2. The RNC generates a list of candidate inter-RAT cells that support DRD and fulfill the qualityrequirement. For details, see chapter3 "RRC DRD." If the candidate cell list is empty, the servicerequest undergoes preemption and queuing.

3. The RNC selects target GSM cells for the service request according to the blind handover priority.The blind handover priority of the cell is specified by the parameterBlindHOPrio.

4. If all admission attempts fail or the number of inter-RAT handover