134170437 directed-retry-decision-libre

Directed Retry Decision RAN12.0

Feature Parameter Description

Issue 03

Date 2010-12-20

HUAWEI TECHNOLOGIES CO., LTD.

Copyright © Huawei Technologies Co., Ltd. 2011. All rights reserved.

No part of this document may be reproduced or transmitted in any form or by any means without prior written consent of Huawei Technologies Co., Ltd.

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

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WCDMA RAN Directed Retry Decision Contents

Issue 03 (2010-12-20) Huawei Proprietary and Confidential Copyright © Huawei Technologies Co., Ltd.

ii

Contents

1 Introduction ................................................................................................................................ 1-1

1.1 Scope ............................................................................................................................................ 1-1

1.2 Intended Audience ........................................................................................................................ 1-1

1.3 Change History .............................................................................................................................. 1-1

2 Overview of DRD ....................................................................................................................... 2-1

3 RRC DRD ..................................................................................................................................... 3-1

4 Non-periodic DRD ..................................................................................................................... 4-1

4.1 Overview ....................................................................................................................................... 4-1

4.1.1 Blind-handover-based Non-periodic DRD ............................................................................ 4-1

4.1.2 Measurement-based Non-periodic DRD .............................................................................. 4-1

4.2 Inter-Frequency DRD Procedure .................................................................................................. 4-2

4.3 DRD for Technological Satisfaction ............................................................................................... 4-3

4.3.1 Overview ............................................................................................................................... 4-3

4.3.2 Priority Sequence of HSPA+ Technologies .......................................................................... 4-4

4.3.3 Procedure of DRD for Technological Satisfaction ................................................................ 4-4

4.4 Inter-Frequency DRD for Service Steering ................................................................................... 4-5

4.4.1 Cell Service Priorities ........................................................................................................... 4-5

4.4.2 Procedure of DRD for Service Steering................................................................................ 4-6

4.5 Inter-Frequency DRD for Load Balancing ..................................................................................... 4-8

4.5.1 Overview of DRD for Load Balancing ................................................................................... 4-8

4.5.2 Power-Based DRD for Load Balancing ................................................................................ 4-8

4.5.3 Code-Based DRD for Load Balancing ................................................................................ 4-12

4.6 Inter-RAT DRD ............................................................................................................................ 4-14

4.7 MBDR .......................................................................................................................................... 4-15

4.7.1 Overview of the MBDR Algorithm ....................................................................................... 4-15

4.7.2 MBDR Algorithm Switches ................................................................................................. 4-15

4.7.3 Procedure for the MBDR Algorithm .................................................................................... 4-15

5 Periodic DRD .............................................................................................................................. 5-1

5.1 Overview ....................................................................................................................................... 5-1

5.1.1 Switches for Periodic DRD ................................................................................................... 5-1

5.1.2 Triggering of Periodic DRD ................................................................................................... 5-1

5.2 Periodic DRD Procedure ............................................................................................................... 5-2

5.2.1 Blind-Handover-Based Periodic DRD .................................................................................. 5-2

5.2.2 Measurement-Based Periodic DRD ..................................................................................... 5-3

6 Parameters ................................................................................................................................. 6-1

7 Counters ...................................................................................................................................... 7-1

WCDMA RAN Directed Retry Decision Contents


iii

8 Glossary ...................................................................................................................................... 8-1

9 Reference Documents ............................................................................................................. 9-1

WCDMA RAN Directed Retry Decision 1 Introduction


1-1

1 Introduction

1.1 Scope

This document describes Directed Retry Decision (DRD). It covers both the RRC DRD and the RAB DRD, and furthermore provides parameter descriptions.

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 the change in the DRD feature.

Editorial change: refers to the change in wording or the addition of the information that was not described in the earlier version.

Document Issues

The document issues are as follows:

03 (2010-12-20)

02 (2010-06-20)

01 (2010-03-30)

Draft (2009-12-05)

03 (2010-12-20)

This is the document for the third commercial release of RAN12.0.

Compared with issue 02 (2010-06-20) of RAN12.0, this issue optimizes the description.

02 (2010-06-20)

This is the document for the second commercial release of RAN12.0.

Compared with issue 01 (2010-03-30) of RAN12.0, this issue corrects the error in 4.6 “Inter-RAT DRD.”

01 (2010-03-30)

This is the document for the first commercial release of RAN12.0.

Compared with issue Draft (2009-12-05) of RAN12.0, this issue incorporates the changes described in the following table.

WCDMA RAN Directed Retry Decision 1 Introduction


1-2

Change Type Change Description Parameter Change

Feature change The description about measurement-based non-periodic DRD (MBDR) is added. For details, see “4.7 MBDR.”

The added parameters are listed as follows:

InterFreqActiveType

InterRatActiveType

UlNonCtrlThdForAMR

UlNonCtrlThdForNonAMR

UlNonCtrlThdForOther

DlConvAMRThd

DlConvNonAMRThd

DlOtherThd

InterFreqUlMbdrTrigThreshold

InterFreqDlMbdrTrigThreshold

InterRatUlMbdrTrigThreshold

InterRatDlMbdrTrigThreshold

UserPercentage

MBDRPrio

MaxAttNum

MBDRFlag

InterFreqReportMode

TrigTime2C

InterFreqMeasQuantity

HOThdEcN0

HOThdRscp

InterRatReportMode

InterRATPeriodReportInterval

InterRATHOThd

TrigTime3C

Editorial change None. None.

Draft (2009-12-05)

This is the draft of the document for RAN12.0.

This is a new document. The description about RRC DRD and non-periodic DRD is separated from the Load Control Feature Parameter Description; the description about periodic DRD is newly added.

Load%20Control.htm

WCDMA RAN Directed Retry Decision 2 Overview of DRD


2-1

2 Overview of DRD

Directed Retry Decision (DRD) is used to select a suitable cell for a UE to access. Different types of DRD can be adopted during different phases of service processing. In this way, the system capacity can be maximized, and better services can be provided.

Figure 2-1 shows the different types of DRD.

Figure 2-1 Types of DRD

RAB DRD is performed during the RAB phase, which starts from RAB setup processing and ends in RAB release. There are two types of RAB DRD, non-periodic DRD and periodic DRD, as shown in Figure 2-1.

DRD Type Application Scenario

Description

RRC DRD During RRC setup

RRC DRD is used to select a suitable inter-frequency neighboring cell for a UE to set up an RRC connection in either of the following situations:

The RRC connection setup fails in the cell that the UE tries to access.

The cell that the UE tries to access does not support signaling radio bearer (SRB) over HSPA when SRB over HSPA is selected as the bearer scheme.

RRC DRD is based on blind handover.

WCDMA RAN Directed Retry Decision 2 Overview of DRD


2-2

DRD Type Application Scenario

Description

Non-periodic DRD

During RAB setup, RAB modification, or DCCC channel reconfiguration

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

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

Measurement-based non-periodic DRD, that is, Measurement Based Directed Retry (MBDR) is used to select a signal qualified cell for a UE according to the measurement result. Compared with blind-handover-based non-periodic DRD, MBDR can increase the DRD success rate when the current cell and the DRD target cell cover different areas.

NOTE:

Blind-handover-based non-periodic DRD cannot work with MBDR. When MBDR is enabled, this type of DRD is disabled automatically.

Periodic DRD

After RAB setup or after the bearer scheme is changed

Periodic DRD is triggered by the HSPA/HSPA+ retry or cell service priority. It can be performed to select a suitable cell when the RNC determines that the UE can be served by a better HSPA/HSPA+ technology or when a neighboring cell has a higher service priority than the current cell. Note that only measurement-based periodic DRD can be triggered by cell service priority.

After periodic DRD is triggered, it can be performed through either of the following two ways:

Blind-handover-based periodic DRD: It mainly applies to the inter-frequency same-coverage scenarios. It selects the target cell that support blind handover and does not consider the signal quality of the target cell.

Measurement-based periodic DRD: It applies to both the inter-frequency different-coverage scenarios and the inter-frequency same-coverage scenarios. It selects the target cell according to the signal measurement results. Only the cell that meets the specified signal conditions can be selected as the target cell.

NOTE:

Blind-handover-based periodic DRD cannot work with measurement-based periodic DRD. When the latter is enabled, the former is disabled automatically.

WCDMA RAN Directed Retry Decision 3 RRC DRD


3-1

3 RRC DRD

RRC DRD is performed during RRC connection setup. When a UE fails to access the current cell, the RNC performs RRC DRD. The purpose is to instruct the UE to set up an RRC connection in a suitable inter-frequency neighboring cell.

The DR_ RRC_DRD_SWITCH subparameter of the DrSwitch parameter determines whether RRC DRD is enabled.

The RRC DRD procedure is as follows:

1. The RNC selects the intra-band inter-frequency neighboring cells of the current cell. These neighboring cells are suitable for blind handovers. Whether the neighboring cells support blind handover is specified by the parameter BlindHoFlag.

2. The RNC generates a list of candidate DRD-supportive inter-frequency cells according to the following condition

(CPICH_EcNo)RACH > DRD_EcNOnbcell

Here:

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

− DRD_EcNOnbcell is the DRD threshold (DRDEcN0Threshhold) of the neighboring cell.

3. The RNC selects a target cell from the candidate cells for UE access. If the candidate cell list is empty, the RRC DRD fails. The RNC performs RRC redirection. If the candidate cell list contains more than one cell, the UE tries a cell randomly.

− If the admission is successful, the RNC continues the RRC connection setup procedure.

− If the admission to a cell fails, the UE tries admission to another cell in the candidate cell list until an admission is successful or all admission attempts fail.

If all the admission attempts fail, then

− The RNC makes an RRC redirection decision when the function of RRC redirection after DRD failure is enabled.

− The RRC connection setup fails when the function of RRC redirection after DRD failure is disabled.

For information about RRC redirection after DRD failure, see the Load Control Feature Parameter Description.

Load%20Control.htm

Load%20Control.htm

WCDMA RAN Directed Retry Decision 4 Non-periodic DRD


4-1

4 Non-periodic DRD

This section involves 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 RAB setup, RAB modification, or DCCC channel reconfiguration.

Non-periodic DRD can be performed based on measurement or blind handover. Blind-handover-based non-periodic DRD and measurement-based non-periodic DRD (that is, MBDR) can not be used simultaneously. When the MBDR algorithm is enabled, other non-periodic DRD algorithms are automatically disabled.

4.1.1 Blind-handover-based Non-periodic DRD

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

The following parameters determine whether to enable blind-handover-based non-periodic DRD:

For a single service, blind-handover-based non-periodic DRD is enabled by the DR_RAB_SING_DRD_SWITCH subparameter of the DrSwitch parameter.

For a service combination, blind-handover-based non-periodic DRD is enabled by the DR_RAB_COMB_DRD_SWITCH subparameter of the DrSwitch parameter.

Note that if the measurement-based periodic DRD switch BasedOnMeasHRetryDRDSwitch is set to ON, blind-handover-based non-periodic DRD is also controlled by the BlindDrdExceptHRetrySwitch parameter.

For example, when the DR_RAB_SING_DRD_SWITCH subparameter of the DrSwitch parameter is set to ON and the BasedOnMeasHRetryDRDSwitch parameter is set to ON, blind-handover-based non-periodic DRD for a single service is enabled only if the BlindDrdExceptHRetrySwitch parameter is set to ON.

For detailed information about blind-handover-based non-periodic DRD, see the following sections:

4.2 Inter-Frequency DRD Procedure

4.3 DRD for Technological Satisfaction

4.4 Inter-Frequency DRD for Service Steering

4.5 Inter-Frequency DRD for Load Balancing

4.6 Inter-RAT DRD

4.1.2 Measurement-based Non-periodic DRD

Measurement-based non-periodic DRD (MBDR) is a feature introduced in RAN12.0. It can increase the success rate of DRD, reduce the service drops caused by DRD with blind handover, and improve the network performance.



4-2

After an RRC connection is set up, the RNC decides whether to establish the requested service in an inter-frequency or inter-RAT cell based on the current cell load and the type of service to be established. If the RNC decides to establish the service in such a neighboring cell, the RNC sends an inter-frequency or inter-RAT measurement control message to the UE, instructing the UE to measure the signal quality of neighboring cells. If the signal quality of a neighboring cell meets the specified requirements, the RNC establishes the service in this cell. Otherwise, the RNC attempts to establish the service in the current cell.

For a type of service, whether MBDR can be performed can be set through the parameters InterFreqActiveType and InterRatActiveTyp.

For detailed information about blind-handover-based non-periodic DRD, see 4.7 MBDR.

4.2 Inter-Frequency DRD Procedure

An inter-frequency DRD procedure consists of DRD for technological satisfaction, DRD for service steering, and DRD for load balancing. The RNC performs these DRDs in sequence, as shown in Figure 4-1.

Figure 4-1 Performing DRDs in sequence

DRD for technological satisfaction

DRD for service steering

DRD for load balancing

Sequence of performing DRDs

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

DRD for technological satisfaction is efficient, but it is applicable only to UEs requesting HSPA+ services. DRD for service steering and DRD for load balancing are controlled by the related parameters.

If all the DRD functions are enabled, the RNC performs the following steps:

1. The RNC determines the candidate cells to which a blind handover can be performed. Whether the neighboring cells support blind handover is specified by the parameter BlindHoFlag. A candidate cell must meet the following conditions:

− The candidate cell supports the requested service.

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

− The current cell meets the quality requirements of inter-frequency DRD. For details, see 3 "RRC DRD."

2. The RNC selects a target cell from the candidate cells for UE access as follows:

(1) The RNC selects a cell with the highest technological satisfaction.

(2) If multiple cells have the highest technological satisfaction or the requested service is not an HSPA+ one, the RNC selects a cell based on DRD for service steering as described in section 4.4 “Inter-Frequency DRD for Service Steering.“



4-3

(3) If multiple cells have the highest service priority, the RNC selects a cell based on DRD for load balancing as described in section 4.4 "Inter-Frequency DRD for Service Steering."

3. The CAC algorithm makes an admission decision based on the resource status 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 candidate cells and then checks whether all candidate cells are tried.

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

b. If all candidate cells haven been tried, then:

− If the service request is an HSPA one, the HSPA request falls back to a DCH one. Then, the algorithm goes back to step 1 to retry admission based on R99 service priorities.

− If the service request is a DCH one, the RNC initiates an inter-RAT DRD.

For UEs requesting the non-HSPA+ services, If both DRD for service steering and DRD for load balancing are disabled, the RNC performs the following steps:

1. The UE attempts to access the current cell when its service priority is not 0. If the service priority of the current cell is 0, the UE attempts to access a neighboring cell with the highest priority of blind handover. The blind handover priority of the cell is specified by the parameter BlindHOPrio.

2. The CAC algorithm makes an admission decision based on the cell status. For details about the CAC procedure, see the Call Admission Control Feature Parameter Description.

− If the admission attempt is successful, the RNC admits the service request.

− If the admission attempt fails, the UE attempts to access another candidate cell randomly.

3. If any request for access to a candidate cell is rejected, then:

− If the service request is an HSPA one, the HSPA request falls back to a DCH one. Then, the algorithm goes back to step 1 to retry admission based on R99 service priorities.

− If the service request is a DCH one, the RNC initiates an inter-RAT DRD. For details about inter-RAT DRD, see section 4.6 "Inter-RAT DRD."

4.3 DRD for Technological Satisfaction

4.3.1 Overview

DRD for technical satisfaction is used to select a suitable cell and HSPA+ technologies for a UE based on the HSPA+ technologies supported by the UE and attributes of the requested service such as the bearer channel, service type, and service rate.

DRD for technical satisfaction consists of the following phases:

1. The RNC determines the HSPA+ technologies that can be configured for the UE, based on the HSPA+ technologies supported by the UE and attributes of the requested service, as described in

the Radio Bearers Feature Parameter Description.

2. The RNC determines the HSPA+ technical satisfaction of each candidate cell based on the priorities of HSPA+ technologies and the intersection of the HSPA+ technologies that can be configured for the UE and supported by the cell.

3. The RNC selects a suitable cell for the UE based on the priority sequence of HSPA+ technologies. In addition, the RNC determines the HSPA+ technologies for the UE, which are the intersection of the HSPA+ technologies that can be configured for the UE and supported by this cell.

Call%20Admission%20Control.htm

Radio%20Bearers.htm



4-4

4.3.2 Priority Sequence of HSPA+ Technologies

From a UE perspective, the technical satisfaction of a cell is determined by the intersection of the HSPA+ technologies that can be configured for the UE and supported by the cell. If the HSPA+ technologies in the intersection have a high priority, the cell has high technical satisfaction.

The HSPA+ technologies comprise DC-HSDPA, enhanced layer 2 (L2), MIMO, 64QAM, DTX+DRX, UL 16QAM, and HS-SCCH Less Operation. The priority sequences of the technologies in a cell supporting HSPA+ are as follows:

When MIMO64QAMorDCHSDPASwitch is set to DC-HSDPA and MIMOor64QAMSwitch to MIMO, the priority sequence is DC-HSDPA (with downlink 64QAM activated in at least one cell) > MIMO+64QAM > DC-HSDPA (with downlink 16QAM activated in at least one cell) > MIMO+DL 16QAM > DL 64QAM > DL enhanced L2 > UL 16QAM > UL enhanced L2 > DTX+DRX > HS-SCCH Less Operation.

When MIMO64QAMorDCHSDPASwitch is set to DC-HSDPA and MIMOor64QAMSwitch to 64QAM, the priority sequence is DC-HSDPA (with downlink 64QAM activated in at least one cell) > MIMO+64QAM > DC-HSDPA (with downlink 16QAM activated in at least one cell) > DL 64QAM > MIMO+DL 16QAM > DL enhanced L2 > UL 16QAM > UL enhanced L2 > DTX+DRX > HS-SCCH Less Operation.

When MIMO64QAMorDCHSDPASwitch is set to MIMO_64QAM and MIMOor64QAMSwitch to MIMO, the priority sequence is MIMO+64QAM > DC-HSDPA (with downlink 64QAM activated in at least one cell) > MIMO+DL 16QAM > DL 64QAM > DC-HSDPA (with downlink 16QAM activated in at least one cell) > DL enhanced L2 > UL 16QAM > UL enhanced L2 > DTX+DRX > HS-SCCH Less Operation.

When MIMO64QAMorDCHSDPASwitch is set to MIMO_64QAM and MIMOor64QAMSwitch to 64QAM, the priority sequence is MIMO+64QAM > DC-HSDPA (with downlink 64QAM activated in at least one cell) > DL 64QAM > MIMO+DL 16QAM > DC-HSDPA (with downlink 16QAM activated in at least one cell) > DL enhanced L2 > UL 16QAM > UL enhanced L2 > DTX+DRX > HS-SCCH Less Operation.

4.3.3 Procedure of DRD for Technological Satisfaction

The procedure for performing DRD for technological satisfaction is as follows:

1. The RNC determines the candidate cells to which blind handovers can be performed. Whether the neighboring cells support blind handover is specified by the parameter BlindHoFlag. A candidate cell must meet the following conditions:




2. The RNC selects a cell with the highest technical satisfaction as the target cell. If multiple cells have the highest technical satisfaction, the RNC selects a suitable cell based on DRD for service steering. Then, if multiple cells have the highest service priority, the RNC selects a suitable cell based on DRD for load balancing.

The RNC also determines the HSPA technologies for the UE in this step.

If the UE requires the DC-HSPA technology, the RNC searches for a DC-HSPA cell group based on the target cell. If multiple DC-HSPA cell groups have the highest technical satisfaction, the RNC selects a suitable cell group based on DRD for service steering. Then, if multiple cell groups have the highest service priority, the RNC selects a suitable cell group based on DRD for load balancing.



4-5

3. The CAC algorithm makes an admission decision based on the resource status of the cell or cell group.

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

− If the admission attempt fails, the RNC removes the cell or cell group from the candidate cells and then checks whether all candidate cells are tried.

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

b. If all candidate cells have been tried and the service request is an HSPA one, the HSPA request falls back to a DCH one to retry admission based on R99 service priorities according to the DRD for service steering and load balancing.

4.4 Inter-Frequency DRD for Service Steering

This section describes the features WRFD-02040004 Traffic Steering and Load Sharing During RAB Setup.

If the UE requests a service in an area covered by multiple frequencies, the RNC selects the cell with the highest service priority for UE access, based on the service type of RAB and the definitions of service priorities in the cells.

The availability of DRD for service steering is specified by the ServiceDiffDrdSwitch parameter.

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

"Inter-frequency DRD for service steering" is called "DRD for service steering" for short in this section.

4.4.1 Cell Service Priorities

A cell service priority is a service-specific priority of a cell among cells under the same coverage. Cell service priorities help achieve traffic absorption in a hierarchical way.

The service priorities of a cell are set as follows:

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

2. Run the ADD UCELLSETUP, MOD UCELLSETUP, or ADD UCELLQUICKSETUP command to assign the SPG identity to the cell, that is, 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 set to 0 in an SPG, the establishment of this service is impossible in the cells belonging to the SPG, regardless of whether DRD for service steering is activated or not.

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

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

Assume that the service priority groups given in the following table are defined on an RNC.



4-6

Cell SPG Identity

Service Priority of R99 RT Service

Service Priority of R99 NRT Service

Service Priority of HSDPA Service

Service Priority of HSUPA Service

Service Priority of Other 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 of the R99 RT service than cell A. If the UE requests an R99 RT service in cell A, preferably the RNC selects cell B for the UE to access.

Figure 4-2 Example of DRD for service steering

If the requested service is a combination of multiple services, the RAB with the highest priority is used when a cell is selected for RAB processing. In addition, the target cell must support all these services.

4.4.2 Procedure of DRD for Service Steering

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



4-7

Figure 4-3 Procedure of DRD for service steering

The procedure of DRD for service steering is as follows:

1. The RNC determines the candidate cells to which blind handovers can be performed and sorts the candidate cells in descending order according to service priority.

A candidate cell must meet the following conditions:

− The candidate cell supports blind handover. Whether the neighboring cells support blind handover is specified by the parameter BlindHoFlag.




2. The RNC selects a target cell from the candidate cells in order of service priority for the UE to access.

If there is more than one cell with the same service priority,

− When the cell, in which the UE requests the service, is one of the candidate cells with the same service priority, preferably, the RNC selects this cell for admission decision.

− Otherwise, the RNC randomly selects a cell as the target cell.

3. 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 removes the cell from the candidate cells and then checks whether all candidate cells are tried.

− If there are any cells where no admission decision has been made, the algorithm goes back to step 2.

− If admission decisions have been made in all the candidate cells, then:

a. If the service request is an HSPA one, the HSPA request falls back to a DCH one. Then, the algorithm goes back to step 1 to make an admission decision based on R99 service priorities.

b. If the service request is a DCH one, the RNC initiates an inter-RAT DRD.

In the case of DC-HSDPA services, if multiple DC-HSDPA cell groups have the highest technical satisfaction, the RNC selects a cell group with the highest service priority.



4-8

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

4.5 Inter-Frequency DRD for Load Balancing

This section involves the feature WRFD-02040004 Traffic Steering and Load Sharing During RAB Setup.

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 achieve load balancing among the cells on the different 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 of DRD for load balancing when DRD for service steering is disabled.

4.5.1 Overview of DRD for Load Balancing

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

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

The availability of power-based DRD for load balancing for DCH service is specified by the LdbDRDSwitchDCH parameter.

The availability of power-based DRD for load balancing for HSDPA service is specified by the LdbDRDSwitchHSDPA parameter.

The availability of code-based DRD for load balancing is specified by the CodeBalancingDrdSwitch parameter.

In practice, it is recommended that only either a power-based DRD for load balancing or a code-based DRD for load balancing be activated. If both are activated, power-based DRD for load balancing takes precedence over code-based DRD for load balancing.

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

4.5.2 Power-Based DRD for Load Balancing

In the Case of Non-DC-HSDPA Services

The following two algorithms are available for power-based load balancing. The algorithm used is specified by the LdbDRDchoice parameter.

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

− For DCH service, the RNC sets up the service on a carrier with a light load of non-HSDPA power to achieve load balancing among the cells at the different frequencies.

− For HSDPA service, the RNC sets up the service on a carrier with a light load of HS-DSCH GBP 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.

− For DCH service, the RNC sets up the service on a carrier with a light load of DCH ENU to achieve load balancing among the cells on different frequencies.

− For HSDPA service, the RNC sets up the service on a carrier with a light load of HSDPA user to achieve load balancing among the cells on different frequencies.



4-9

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

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

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

1. The RNC determines the candidate cells to which blind handovers can be performed.

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





2. If the current cell meets the preceding conditions, the RNC proceeds to step 3. Otherwise, the RNC selects the cell with lowest load from the candidate cell list and goes to step 5.

3. The RNC determines whether the current cell meets the following condition (condition 1).

− For algorithm 1, condition 1 is as follows:



4-10

a. For DCH service

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

Here,

ThdAMR,cutcell is specified by DlConvAMRThd.

Pnon-H,cutcell is the Non-HSDPA power load of the current cell.

Thdnon-H is specified by LdbDRDLoadRemainThdDCH.

b. For HSDPA service

(Thdtotal,cutcell - PGBP,cutcell) > ThdH

Here,

Thdtotal,cutcell is specified by DlCellTotalThd.

PGBP,cutcell is the HS-DSCH GBP load of the current cell.

ThdH is specified by LdbDRDLoadRemainThdHSDPA.

− For algorithm 2, condition 1 is as follows:

a. For DCH service

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

Here, PD-enu,cutcell is DCH ENU load of the current cell.

b. For HSDPA service

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

Here,

ThdH-ue,cutcell is specified by MaxHsdpaUserNum.

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

If... Then...

Condition 1 is met For non-DC-HSDPA services:

If the current cell does not support DC-HSDPA, the service tries admission to the current cell. Goes to step 5.

If the DC-HSDPA cell group is selected, the cell with the lowest load is selected. Goes to step 5.

Condition 1 is not met Goes to step 4.

4. The RNC selects a target cell for the UE to access.

The RNC determines whether any inter-frequency neighboring cell meets the following condition (condition 2):

For algorithm 1, condition 2 is as follows:

− For DCH service

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

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

Here,

ThdAMR,nbcell is specified by DlConvAMRThd.

Pnon-H,nbcell is the Non-HSDPA power load of the neighboring cell.



4-11

ThdD,loadoffset is specified by LdbDRDOffsetDCH.

Pload,cutcell is the sum of the non-HSDPA power and the GBP load of the current cell.

Thdtotal,nbcell is specified by DlCellTotalThd.

Pload,nbcell is the sum of the non-HSDPA power and the GBP load of the neighboring cell.

Thdtotal,loadoffset is specified by LdbDRDTotalPwrProThd.

For HSDPA service

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

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

Here,

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

ThdH,loadoffset is specified by LdbDRDOffsetHSDPA.

For algorithm 2, condition 2 is as follows:

− For a DCH service

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

Here, PD-enu,nbcell is the DCH ENU load of the neighboring cell.

− For an HSDPA service

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

Here,

ThdH-ue,nbcell is specified by MaxHsdpaUserNum.

PH-ue,nbcell is 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 the condition 2, the RNC selects this cell as the target cell. If there are multiple such cells:

− For a DCH service

a. If algorithm 1 is used, the RNC selects the cell with the lightest non-HSDPA load as the target cell.

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

− For an HSDPA service

a. If algorithm 1 is used, the RNC selects the cell with the lightest load of HS-DSCH required power as the target cell.

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

If there is no such cell, the RNC selects the current cell as the target cell.


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

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

− If there is any cell where no admission decision is made, the algorithm goes back to step 2.

− If admission decisions have been made in 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 1 to make an admission decision based on R99 service priorities.

b. When the service request is a DCH one, the RNC initiates an inter-RAT DRD.



4-12

In the Case of DC-HSDPA Services

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

DRD for load balancing in the case of DC-HSDPA services is similar to that in the case of non-DC-HSDPA services. The difference is that the former considers cell groups (not individual cells), calculates the load factors of cell groups, and finally selects a suitable cell group.

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

If the uplink load balancing switch ULLdbDRDSwitchDcHSDPA is turned off, the RNC selects either of 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 the primary cell for multiple UEs requesting DC-HSDPA services.

The uplink load balancing between the two cells is performed based on the uplink ENU:

During Uplink load balancing, if the serving cell is not in the target DC-HSDPA cell group, the RNC selects a primary cell with lower load. Otherwise, the RNC checks whether the UL load margin of the serving cell is higher than the value of ULLdbDRDLoadRemainThdDCHSDPA:

If the condition is met, the RNC selects the serving cell as the primary cell.

If the condition is not met, the RNC calculates the difference between the UL load margin of the serving cell and that of the target cell. Then,

− If the difference is greater than the value of ULLdbDRDOffsetDcHSDPA, the RNC selects the target cell as the primary cell.

− Otherwise, the RNC selects the serving cell as the primary cell.

4.5.3 Code-Based DRD for Load Balancing

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

The following figure shows the procedure for selecting a target cell based on code resource.



4-13

Figure 4-5 Procedure of 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 the minimum SF threshold of DRD for code balancing (CodeBalancingDrdMinSFThd).

If the minimum SF is smaller than this threshold, the RNC tries the admission of the service request to the current cell.

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

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

If the code load is lower than this threshold, the service tries the admission to 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 by the current cell, and the difference between the code resource occupancies of the two is larger than or equal to the value of DeltaCodeOccupiedRate, the RNC selects the cell with the lightest code load as the target cell. Otherwise, the RNC selects the current cell as the target cell.



4-14

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

4.6 Inter-RAT DRD

When all admission attempts for inter-frequency DRD during RAB processing fail, the RNC determines whether to initiate an inter-RAT DRD.

The following figure shows the inter-RAT DRD procedure.

Figure 4-6 Inter-RAT DRD procedure

The inter-RAT DRD procedure is as follows:

1. If the current cell is configured with any neighboring GSM cell suitable for blind handover, and if the "service handover" IE that is contained in the RAB assignment signaling assigned by the CN is set to "handover to GSM should be performed" or "handover to GSM should not be performed" , then the RNC performs step 2. Otherwise, the service request undergoes preemption and queuing.

Whether the neighboring cells support blind handover is specified by the parameter BlindHoFlag.

2. The RNC generates a list of candidate DRD-supportive inter-RAT cells that fulfill the quality requirement. For details, see 3 "RRC DRD". If the candidate cell list does not include any cell, the service request 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 parameter BlindHOPrio.

4. If all admission attempts fail or the number of inter-RAT handover retries exceeds the value of DRMaxGSMNum, the service request undergoes preemption and queuing.



4-15

The Inter-RAT DRD is not applicable to RABs of combined services, R99 PS services, and HSPA services.

4.7 MBDR

This section describes the feature WRFD-020402 Measurement based Direct Retry.

4.7.1 Overview of the MBDR Algorithm

When an RAB is set up, the DRD algorithm uses the blind handover procedure to achieve load balancing and service steering. In this situation, if the current cell and the DRD target cell cover different areas, the UE DRD may fail.

After the Measurement Based Directed Retry (MBDR) function is implemented, inter-frequency or inter-RAT measurement is performed. This ensures good signal quality of the DRD target cell. With this function, the success rate of inter-frequency or inter-RAT DRD can be ensured even if the current cell and the DRD target cell cover different areas. The UE access delay, however, is increased.

Note that the MBDR algorithm cannot be used with other non-periodic DRD algorithms simultaneously. When the MBDR algorithm is enabled, other non-periodic DRD algorithms are automatically disabled.

4.7.2 MBDR Algorithm Switches

The MBDR algorithm switches are InterFreqActiveType and InterRatActiveType. They specify whether a type of service can use MBDR.

The following types of service support inter-frequency MBDR:

− CS AMR

− CS non-AMR

− PS R99

− PS HSPA

Only CS AMR services support inter-RAT MBDR.

4.7.3 Procedure for the MBDR Algorithm

Overview

After an RRC connection setup, the RNC determines whether to establish services in inter-frequency or inter-RAT cells based on the current cell load and the type of services to be established. If required, the RNC sends the UE an inter-frequency or inter-RAT measurement control message, instructing the UE to measure the signal quality of the target cell. If the signal quality of the target cell meets the specified requirements, the RNC establishes services in the target cell. Otherwise, the RNC attempts to establish services in the current cell.

The procedure for the inter-frequency MBDR algorithm is as follows:

1. After an RRC connection setup, the MBDR algorithm triggers the measurement of an inter-frequency MBDR cell if the corresponding MBDR algorithm switch is turned on and the current cell load exceeds the MBDR congestion decision threshold.

2. The RNC sends the UE an inter-frequency measurement control message, instructing the UE to measure the signal quality of the inter-frequency MBDR cell. If the signal quality of the inter-frequency MBDR cell meets the specified requirements, the RNC establishes services in this cell.

If several inter-frequency MBDR cells are qualified, the RNC prioritizes these cells and establishes services in the cell with the highest priority.



4-16

3. If services are established successfully, the RAB is set up successfully. Otherwise, the RNC attempts to establish services in the cell with the second highest priority.

The procedure for the inter-RAT MBDR algorithm is similar to that for the inter-frequency MBDR algorithm.

Trigger Conditions of MBDR

After an RRC connection setup, if the MBDR algorithm switch for the service type to which this RAB belongs is turned on, the RNC triggers MBDR when either of the following conditions is met:

The uplink admission control switch NBMUlCacAlgoSelSwitch is not set to ALGORITHM_OFF, and the cell is in the MBDR congestion state, that is, the formula {Uplink admission threshold × MBDR congestion decision threshold ≤ Current cell load factor ≤ Uplink admission threshold } is fulfilled.

The downlink admission control switch NBMDlCacAlgoSelSwitch is not set to ALGORITHM_OFF, and the cell is in the MBDR congestion state, that is, the formula {Downlink admission threshold × MBDR congestion decision threshold ≤ Current cell load factor ≤ Downlink admission threshold } is fulfilled.

In the above two formulas:

The uplink admission threshold is specified by the UlNonCtrlThdForAMR, UlNonCtrlThdForNonAMR, or UlNonCtrlThdForOther parameter. The downlink admission threshold is specified by the DlConvAMRThd, DlConvNonAMRThd, or DlOtherThd parameter.

The MBDR congestion decision threshold is specified by the InterFreqUlMbdrTrigThreshold, InterFreqDlMbdrTrigThreshold, InterRatUlMbdrTrigThreshold, or InterRatDlMbdrTrigThreshold parameter.

The current cell load factor indicates the percentage of the used cell capacity to the total cell capacity. The current cell load factor in both uplink and downlink is calculated by the RNC according to the cell load measurement results reported by the NodeB. For details, see the Load Control Parameter Description.

In the case of inter-RAT MBDR, the RNC triggers MBDR for only a certain percentage of UEs that meet the trigger conditions. This percentage is specified by the UserPercentage parameter.

MBDR Target Cell Selection

After MBDR is triggered, the RNC starts target cell selection.

If the current cell has only one MBDR neighboring cell, the RNC sends the UE a measurement request, instructing the UE to measure the signal quality of this neighboring cell. If the measured signal quality meets the specified requirements, the RNC establishes services in this neighboring cell. If service establishment fails, the RNC establishes services in the current cell.

If the current cell has more than one MBDR neighboring cell, the following procedure is triggered:

1. The RNC sends the UE a measurement request, instructing the UE to measure the signal quality of all the MBDR neighboring cells.

2. According to the measurement results, the RNC selects the neighboring cells that meet the specified requirements as target cells. Note that the neighboring cell in the MBDR congestion state can not be selected as target cell.

− If only one neighboring cell meets the specified requirements, the RNC establishes services in this neighboring cell.

− If more than one neighboring cell meets the specified requirements, the RNC prioritizes these cells based on the value of the MBDRPrio parameter and then establishes services in the cell with the highest priority. If these cells have the same priority, the RNC randomly selects one of them and then establishes services in this cell. A smaller value of MBDRPrio indicates a higher priority.



4-17

3. If services fail to be established in the cell with the highest priority, the RNC attempts to establish services in the cell with the second highest priority. If service establishment still fails, the RNC tries the neighboring cell with the third highest priority. By this analogy, the RNC establishes services in the current cell only after the number of attempts exceeds the value of the MaxAttNum parameter or after the RNC tries all the target cells.

MBDR neighboring cells are specified by the MBDRFlag parameter.

Measurement Control Items

After MBDR is triggered, the RNC sends the UE a measurement control message, instructing the UE to measure the signal quality of the target cell. After measurement, the UE reports the measurement results to the RNC.

The parameters associated with measurement control items, for example, the measurement report mode and trigger threshold, can be configured by running the ADD CELLMBDRINTERFREQ or ADD CELLMBDRINTERRAT command.

In the case of inter-frequency MBDR, you can:

Set the InterFreqReportMode parameter to PERIODICAL_REPORTING or EVENT_TRIGGER.

− If the InterFreqReportMode parameter is set to PERIODICAL_REPORTING, the UE reports measurement results to the RNC at an interval of PrdReportInterval. Then, the RNC determines whether the signal quality of this inter-frequency cell meets the specified requirements according to the measurement results and the tigger conditions.

− If the InterFreqReportMode parameter is set to EVENT_TRIGGER, the UE sends the RNC a measurement report (indicating that the signal quality of the inter-frequency cell meets the inter-frequency handover requirements) when the signal quality of the inter-frequency cell is higher than the trigger threshold for the period specified by TrigTime2C.

Set the InterFreqMeasQuantity parameter to Ec/No, RSCP, or BOTH.

The InterFreqMeasQuantity parameter cannot be set to BOTH if the InterFreqReportMode parameter is set to EVENT_TRIGGER.

− If the InterFreqMeasQuantity parameter is set to Ec/No, the Ec/No value of the target cell must reach the inter-frequency handover trigger threshold, which is specified by the HOThdEcN0 parameter.

− If the InterFreqMeasQuantity parameter is set to RSCP, the RSCP value of the target cell must reach the inter-frequency handover trigger threshold, which is specified by the HOThdRscp parameter.

− If the InterFreqMeasQuantity parameter is set to BOTH, both the Ec/No and RSCP values of the target cell must reach the corresponding inter-frequency handover trigger threshold.

In the case of inter-RAT MBDR, you can set the InterRatReportMode parameter to PERIODICAL_REPORTING or EVENT_TRIGGER.

If the InterRatReportMode parameter is set to PERIODICAL_REPORTING, the UE reports measurement results to the RNC at an interval of InterRATPeriodReportInterval. Then, the RNC compares the measurement results with InterRATHOThd to determine whether the signal quality of this inter-RAT cell meets the specified requirements.

If the InterRatReportMode parameter is set to EVENT_TRIGGER, the UE sends the RNC a measurement report (indicating that the signal quality of the inter-RAT cell meets the inter-RAT handover requirements) when the signal quality of the inter-RAT cell is higher than the trigger threshold for the period specified by TrigTime3C.



4-18

The measurement mechanism for inter-frequency or inter-RAT MBDR is the same as that for handover. For details about the measurement mechanism, see the Handover Parameter Description.

WCDMA RAN Directed Retry Decision 5 Periodic DRD


5-1

5 Periodic DRD

5.1 Overview

5.1.1 Switches for Periodic DRD

The DR_RAB_SING_DRD_SWITCH and DR_RAB_COMB_DRD_SWITCH subparameters of the DrSwitch parameter determine whether to enable RAB DRD for a single service and a service combination respectively. The BasedOnMeasHRetryDRDSwitch parameter further determines whether to enable blind-handover-based non-periodic DRD, blind-handover-based periodic DRD, or measurement-based periodic DRD.

When the subparameter DR_RAB_SING_DRD_SWITCH or DR_RAB_COMB_DRD_SWITCH is set to ON, the functions of the BasedOnMeasHRetryDRDSwitch parameter are as follows:

When the BasedOnMeasHRetryDRDSwitch parameter is set to ON:

− Measurement-based periodic DRD is enabled.

− Blind-handover-based periodic DRD is disabled.

− Blind-handover-based non-periodic DRD is further controlled by the BlindDrdExceptHRetrySwitch parameter.

When the BasedOnMeasHRetryDRDSwitch parameter is set to OFF:

− Measurement-based periodic DRD is disabled.

− Blind-handover-based periodic DRD is enabled if the ChannelRetryTimerLen parameter is not set to 0.

− Blind-handover-based non-periodic DRD is enabled.

5.1.2 Triggering of Periodic DRD

Periodic DRD is triggered by the HSPA/HSPA+ retry. The HSPA/HSPA+ retry can be performed after the bearer scheme of a service is changed, for example, after RAB setup, RAB modification, soft handover, hard handover, or best cell change.

After the bearer scheme of a service is changed, the RNC determines whether the UE can be served by a better HSPA/HSPA+ technology by considering the technological satisfaction. If a better HSPA/HSPA+ technology can be used, the HSPA/HSPA+ retry is performed and consequently periodic DRD is triggered. In this way, a suitable cell can be selected to serve the UE with a better HSPA/HSPA+ technology.

Measurement-based periodic DRD can also be triggered when a neighboring cell has a higher service priority than the current cell. In this way, service steering is achieved.

In different situations, HSPA/HSPA+ technologies that can trigger HSPA/HSPA+ retry and consequently periodic DRD are different. The conditions on which an HSPA/HSPA+ technology can trigger HSPA/HSPA+ retry and consequently periodic DRD are as follows:

The HSPA+ technology must be selected through RetryCapability parameter.

This condition does not apply to the HSPA technologies.

The HSPA/HSPA+ technology must be supported by periodic DRD.

Note that different types of periodic DRD support different HSPA/HSPA+ technologies.



5-2

− For blind-handover-based periodic DRD, the supported HSPA/HSPA+ technologies are HSUPA, HSDPA, 64QAM, MIMO, and DC-HSDPA.

− For measurement-based periodic DRD, the supported HSPA/HSPA+ technologies are HSDPA, HSUPA, uplink enhanced L2, uplink 16QAM, downlink enhanced L2, CPC, 64QAM, DC-HSDPA, and MIMO.

The reason why measurement-based periodic DRD supports more HSPA+ technologies than blind-handover-based periodic DRD is as follows: When measurement-based periodic DRD is enabled, non-periodic DRD may not be applied. In such a case, the HSPA+ technologies that are supported by non-periodic DRD can be supported by measurement-based periodic DRD. In this way, the function of non-periodic DRD can be indirectly implemented through measurement-based periodic DRD.

When measurement-based periodic DRD is enabled, whether non-periodic DRD can be applied is further determined by the BlindDrdExceptHRetrySwitch parameter. For details, see 4 “Non-periodic DRD.”

5.2 Periodic DRD Procedure

5.2.1 Blind-Handover-Based Periodic DRD

Blind-handover-based periodic DRD applies to the inter-frequency same-coverage scenarios. It is performed at regular intervals. The interval is specified by the ChannelRetryTimerLen parameter.

Figure 5-1 shows the procedure of blind-handover-based periodic DRD.

Figure 5-1 Procedure of blind-handover-based periodic DRD

The procedure of blind-handover-based periodic DRD is as follows:

1. The RNC decides whether candidate cells that the UE can retry accessing exist. The candidate cells are selected from the same-coverage neighboring cells of the current best cell. A candidate cell must meet the following conditions:



5-3


− The frequency of the cell is within the band supported by the UE.

− The cell supports the requested service.

− The cell is not overloaded.

− The HSPA+ technological satisfaction of the cell is higher than that of the current cell.

If such candidate cells do not exist, the procedure of blind-handover-based periodic DRD fails. In such a case, the RNC waits for the next DRD period.

If such candidate cells exist, the following step is performed.

2. The RNC sequences the candidate cells according to the HSPA+ technological satisfaction.

3. The RNC selects a target cell for UE access according to the sequence from the highest to the lowest.



If the admission attempt fails, the RNC removes the cell from the candidate cells and then checks whether all candidate cells are tried.


− If admission decisions fail in all the candidate cells, the procedure of blind-handover-based periodic DRD fails. In such a case, the RNC waits for the next DRD period.

5.2.2 Measurement-Based Periodic DRD

In a multi-band network, the cells that operate on different frequency bands have different coverage areas. When a UE needs to perform an inter-frequency handover in a multi-band network, it normally does not perform a blind handover as the success rate of the blind handover is relatively low. Instead, the UE performs handover decision according to the signal of each inter-frequency cell. Measurement-based periodic DRD is introduced to select a signal-qualified cell for the UE to access.

Measurement-based periodic DRD applies to both the inter-frequency same-coverage scenarios and the inter-frequency different-coverage scenarios. It can increase the DRD success rate in both the same-coverage scenarios and the different-coverage scenarios.

Figure 5-2 shows the procedure of measurement-based periodic DRD.



5-4

Figure 5-2 Procedure of measurement-based periodic DRD

The procedure of measurement-based periodic DRD is as follows:

1. Based on HSPA+ technological satisfaction and cell service priority, the RNC decides whether candidate cells that the UE can retry accessing exist. The candidate cells are selected from the best cell and its neighboring cells.

A candidate cell must meet the following conditions:

− The frequency of the cell is within the band supported by the UE.

− The cell supports the requested service.

− The DrdOrLdrFlag parameter of the cell is set to True, indicating that the cell can be measured.

− The HSPA+ technological satisfaction of the cell is higher than that of the current cell, or the service priority of the cell is higher than or equal to that of the current cell.

For details about the HSPA+ technological satisfaction and cell service priority, see the Load Control Feature Parameter Description.

If such candidate cells exist, the following step is performed.

2. The RNC starts the timer for periodic DRD. The length of the timer is specified by the HRetryTimerLength parameter.

− If there is only one candidate cell and it is the current cell, the UE retries higher HSPA+ technologies in the current cell when the timer expires.

− In other situations, the RNC issues a measurement control message, requesting the UE to measure the signal quality of all candidate cells.

3. The UE measures the RSCP and Ec/No of the candidate cells and periodically reports the measurement results to the RNC. The reporting period is specified by the PrdReportInterval parameter.

Load%20Control.htm

Load%20Control.htm



5-5

4. Based on the received measurement results, the RNC selects the candidate target cells.

A candidate target cell must meet the following conditions:

− The cell is not overloaded.

− The measured RSCP is higher than the RSCP threshold that is specified by the TargetFreqThdRscp parameter.

− The measured Ec/No is higher than the Ec/No threshold that is specified by the TargetFreqThdEcN0 parameter.

If such candidate target cells do not exist, the procedure of measurement-based periodic DRD fails. In such a case, the RNC waits for the DRD timer to expire.

If such candidate target cells exist, the following step is performed.

5. The RNC sequences the candidate target cells according to the HSPA+ technological satisfaction and cell service priority.

6. The RNC selects a candidate target cell for UE access according to the sequence from the highest to the lowest.

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


If the admission attempt fails, the RNC removes the cell from the candidate target cells and then checks whether all candidate target cells are tried.


− If admission decisions fail in all the candidate target cells, the procedure of measurement-based periodic DRD fails. In such a case, the RNC waits for the DRD timer to expire.

If the measurement or retry fails during the procedure of measurement-based periodic DRD, a failure penalty timer is started when the DRD timer expires. During the penalty time, such a procedure cannot be performed and the UE can retry accessing only the current cell. The length of the penalty timer is specified by multiplying the value of the HRetryTimerLength parameter by the value of the DrdFaiPenaltyPeriodNum parameter.

WCDMA RAN Directed Retry Decision 6 Parameters


6-1

6 Parameters Table 6-1 Parameter description

Parameter ID NE MML Command Description

BasedOnMeasHRetryDRDSwitch

BSC6900

SET UDRD(Optional)

Meaning: Controls the validity of the measurement-based DRD algorithm. Assume that the DRD algorithm is enabled. If the switch is on, the RNC uses the DRD algorithm based on the measurement (for measuring the signals in the neighboring cell of the best cell). You can run the "SET UMCDRD" command to configure the related parameters. If the switch is off, the RNC implements the DRD algorithm based on blind handovers. Note: When the measurement-based DRD algorithm is used, you need to measure the signal quality of the target cell before a DRD retry. This cell can act as the actual target cell only when its signal quality meets the preset threshold. The measurement-based DRD is performed only for the periodic retry flow. GUI Value Range: OFF, ON Actual Value Range: OFF, ON Unit: None Default Value: OFF

BlindDrdExceptHRetrySwitch

BSC6900

ADD UCELLMCDRD(Optional) MOD UCELLMCDRD(Optional)

Meaning: When the measurement-based DRD is performed, this parameter is used to determine whether the DRD retry for blind handover is performed in aperiodic mode. The aperiodic retry includes the setup of the RAB, modification of the RAB, and DCCC channel handover. If this parameter is set to "ON", the DRD retry for blind handover is performed in aperiodic mode. If this switch is set to "OFF", the DRD retry for blind handover is not performed in aperiodic mode. GUI Value Range: OFF, ON Actual Value Range: OFF, ON Unit: None Default Value: OFF

ChannelRetryTimerLen

BSC6900

SET UCOIFTIMER(Optional)

Meaning: This parameter specifies the value of the channel retry timer. The timer will start when traffic is set up or reconfigured and some higher technique is not configured by some reason except for the capability of UE or cell. Channel retry will be performed after this timer expires. GUI Value Range: 0~180 Actual Value Range: 0~180 Unit: s Default Value: 5



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CodeBalancingDrdCodeRateThd

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ADD UCELLDRD(Optional) MOD UCELLDRD(Optional)

Meaning: One of the triggering conditions of code balancing DRD. The other condition is the minimum spreading factor. Code balancing DRD is applied only when the code occupancy in the best cell is not lower than the value of this parameter. GUI Value Range: 0~100 Actual Value Range: 0~100 Unit: % Default Value: 13

CodeBalancingDrdMinSFThd

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Meaning: One of the triggering conditions of code balancing DRD. The other condition is the code occupancy threshold. Code balancing DRD is applied only when the minimum spreading factor in the best cell is not lower than the value of this parameter. GUI Value Range: SF4, SF8, SF16, SF32, SF64, SF128, SF256 Actual Value Range: SF4, SF8, SF16, SF32, SF64, SF128, SF256 Unit: None Default Value: SF8

CodeBalancingDrdSwitch

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Meaning: Whether to apply the code balancing DRD algorithm. The "DR_RAB_SING_DRD_SWITCH" parameter in "SET UCORRMALGOSWITCH" needs to be enabled. For combination services, the "DR_RAB_COMB_DRD_SWITCH" parameter needs to be enabled. GUI Value Range: ON, OFF Actual Value Range: ON, OFF Unit: None Default Value: OFF

ConnectFailRrcRedirSwitch

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SET UDRD(Optional)

Meaning: RRC redirection switch used in the case of admission failure. It is valid only when the "DR_RRC_DRD_SWITCH" parameter is set to ON. - OFF indicates that the RRC redirection is not allowed. - Only_To_Inter_Frequency indicates that only RRC redirection to inter-frequency cells is allowed. - Allowed_To_Inter_RAT indicates that both RRC redirection to inter-frequency cells and redirection to inter-RAT cells are allowed. GUI Value Range: OFF, Only_To_Inter_Frequency, Allowed_To_Inter_RAT Actual Value Range: OFF, Only_To_Inter_Frequency, Allowed_To_Inter_RAT Unit: None Default Value: Only_To_Inter_Frequency



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DeltaCodeOccupiedRate

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SET UDRD(Optional)

Meaning: Threshold of code occupancy offset between the current cell and the target cell when code balancing DRD is applied. Only when the cell code occupancy offset reaches this threshold can a neighboring cell be selected to be a candidate cell for DRD. GUI Value Range: 0~100 Actual Value Range: 0~100 Unit: % Default Value: 7

DlCellTotalThd BSC6900

ADD UCELLCAC(Optional) MOD UCELLCAC(Optional)

Meaning: Admission threshold of the total cell downlink power. If the value is too high, too many users will be admitted. However, the throughput of a single user is easy to be limited. If the value is too low, cell capacity will be wasted. GUI Value Range: 0~100 Actual Value Range: 0~1, step:0.01 Unit: % Default Value: 90

DlConvAMRThd BSC6900


Meaning: The percentage of the conversational AMR service threshold to the 100% downlink load. It is applicable to algorithm 1 and algorithm 2. The parameter is used for controlling the AMR service admission. That is, when an AMR service is accessing, the RNC evaluates the measurement value of the downlink load after the service is accessed. If the DL load of a cell is higher than this threshold after the access of an AMR speech service, this service will be rejected. If the DL load of a cell will not be higher than this threshold, this service will be admitted. The DL load factor thresholds include parameters of [DL threshold of Conv non_AMR service], [DL handover access threshold] and [DL threshold of other services]. The four parameters can be used to limit the proportion between the conversational service, handover user and other services in a specific cell, and to guarantee the access priority of the conversational AMR service. GUI Value Range: 0~100 Actual Value Range: 0~1, step:0.01 Unit: % Default Value: 80



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DlConvNonAMRThd

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Meaning: The percentage of the conversational non-AMR service threshold to the 100% downlink load. It is applicable to algorithm 1 and algorithm 2. The parameter is used for controlling the non-AMR service admission. That is, when a non-AMR service is accessing, the RNC evaluates the measurement value of the downlink load after the service is accessed. If the DL load of a cell is higher than this threshold after the access of a non-AMR speech service, this service will be rejected. If the DL load of a cell will not be higher than this threshold, this service will be admitted. The DL load factor thresholds include parameters of [DL threshold of Conv non_AMR service], [DL handover access threshold] and [DL threshold of other services]. The four parameters can be used to limit the proportion between the conversational service, handover user and other services in a specific cell, and to guarantee the access priority of the conversational non-AMR service. GUI Value Range: 0~100 Actual Value Range: 0~1, step:0.01 Unit: % Default Value: 80

DlOtherThd BSC6900


Meaning: The percentage of other service thresholds to the 100% downlink load. The services refer to other admissions except the conversational AMR service, conversational non-AMR service, and handover scenarios. It is applicable to algorithm 1 and algorithm 2. The parameter is used for controlling other service admissions. That is, when a service is accessing, the RNC evaluates the measurement value of the downlink load after the service is accessed. If the DL load of a cell is higher than this threshold after the access of a service, this service will be rejected. If the DL load of a cell will not be higher than this threshold, this service will be admitted. The DL load factor thresholds include parameters of [DL threshold of Conv non_AMR service], [DL handover access threshold] and [DL threshold of other services]. The four parameters can be used to limit the proportion between the conversational service, handover user and other services in a specific cell, and to guarantee the access priority of other services. GUI Value Range: 0~100 Actual Value Range: 0~1, step:0.01 Unit: % Default Value: 75



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DRDEcN0Threshhold

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ADD U2GNCELL(Optional) MOD U2GNCELL(Optional)

Meaning: DRD Ec/No threshold for determining whether to perform the blind handover. The DRD is permitted if Ec/No of the current cell is greater than the DRD Ec/No threshold of a inter-RAT/inter-frequency neighboring cell. GUI Value Range: -24~0 Actual Value Range: -24~0 Unit: dB Default Value: -18

DrdFaiPenaltyPeriodNum

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Meaning: Number of retry periods in the interval between a failure of a measurement-based DRD re-attempt and the initiation of the next DRD re-attempt. If this parameter is set to a great value, the probability of a user re-accessing a cell with a high priority becomes low; If this parameter is set to a small value, the probability of a user re-accessing a cell with a high priority becomes high; however, the performance is greatly affected. Note: The process of a measurement-based DRD retry is as follows: At the beginning, the RNC determines to enable the DRD retry; then, it starts inter-frequency measurement control; next, the RNC receives the measurement report from a UE; after that, the RNC retries the access to a cell in the reported DRD cell list. The process ends until the cell access succeeds. GUI Value Range: 1~65535 Actual Value Range: 1~65535 Unit: None Default Value: 10

DrdOrLdrFlag BSC6900

ADD UINTERFREQNCELL(Optional) MOD UINTERFREQNCELL(Optional)

Meaning: Specify the flags of the cells that the DRD measurement or LDR measurement is performed. The value "TRUE" indicates that the cell can be considered as the measurement object in the DRD measurement algorithm or LDR measurement algorithm. The value "FALSE" indicates that the cell is invalid. GUI Value Range: FALSE(Do not send), TRUE(Send) Actual Value Range: FALSE, TRUE Unit: None Default Value: False

DRMaxGSMNum

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Meaning: Maximum number of inter-RAT RAB directed retries. It decides the size of the candidate set for inter-RAT DRD. The value 0 indicates that inter-RAT RAB DRD is not applicable. This parameter can be cell-oriented. GUI Value Range: 0~5 Actual Value Range: 0~5 Unit: None Default Value: 2



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DrSwitch BSC6900

SET UCORRMALGOSWITCH(Optional)

Meaning: Direct retry switch group. 1) DR_RRC_DRD_SWITCH(DRD switch for RRC connection): When the switch is on, DRD and redirection is performed for RRC connection if retry is required. 2) DR_RAB_SING_DRD_SWITCH(DRD switch for single RAB): When the switch is on, DRD is performed for single service if retry is required. 3) DR_RAB_COMB_DRD_SWITCH(DRD switch for combine RAB): When the switch is on, DRD is performed for combined services if retry is required. GUI Value Range: DR_RRC_DRD_SWITCH, DR_RAB_SING_DRD_SWITCH, DR_RAB_COMB_DRD_SWITCH Actual Value Range: DR_RRC_DRD_SWITCH, DR_RAB_SING_DRD_SWITCH, DR_RAB_COMB_DRD_SWITCH Unit: None Default Value: None

HOThdEcN0 BSC6900

ADD UCELLMBDRINTERFREQ(Optional) MOD UCELLMBDRINTERFREQ(Optional)

Meaning: Threshold of signal quality of the target frequency for triggering inter-frequency(Ec/No) measurement. If the mode is set to event mode, this parameter is used to set measurement control on the event 2C. If the mode is set to periodical mode, this parameter is used to estimate the periodical reports and only if quality of the target frequency is beyond the threshold, the DRD procedure is triggered. GUI Value Range: -24~0 Actual Value Range: -24~0 Unit: dB Default Value: -16

HOThdRscp BSC6900


Meaning: Threshold of signal quality of the target frequency for triggering inter-frequency(RSCP) measurement. If the mode is set to event mode, this parameter is used to set measurement control on the event 2C. If the mode is set to periodical mode, this parameter is used to estimate the periodical reports and only if quality of the target frequency is beyond the threshold, the DRD procedure is triggered. GUI Value Range: -115~-25 Actual Value Range: -115~-25 Unit: dB Default Value: -92



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HRetryTimerLength

BSC6900


Meaning: Specifies the time length of the measurement-based DRD periodic retry timer. After the service is set up or the data reconfiguration is complete, and if the service data can be carried by the neighboring cell applied with an advanced technology or carried by the HCS cell with a higher priority, you need to enable the measurement-based DRD periodic retry timer, initiate an inter-frequency measurement for the DRD inter-frequency neighboring cell, and initiate the channel retry when the inter-frequency measurement report from the UE is received. When the timer expires, the channel retry can be initiated only in this cell. If this parameter is set to a greater value, the probability for subscribers to re-access the cell with a high priority becomes low. If this parameter is set to a smaller value, the probability for subscribers to re-access the cell with a high priority becomes high. GUI Value Range: 1~255 Actual Value Range: 1~255 Unit: s Default Value: 10

InterFreqActiveType

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Meaning: MBDR switch GUI Value Range: CSAMR_INTERFREQ(CS AMR inter-frequency switch), CSNONAMR_INTERFREQ(CS non AMR inter-frequency switch), PSR99_INTERFREQ(PSR99 inter-frequency switch), PSHSPA_INTERFREQ(PSHSPA inter-frequency switch) Actual Value Range: CSAMR_INTERFREQ, CSNONAMR_INTERFREQ, PSR99_INTERFREQ, PSHSPA_INTERFREQ Unit: None Default Value: None

InterFreqDlMbdrTrigThreshold

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Meaning: This parameter is the relative threshold of cell for judging whether downlink MBDR algorithm of inter frequency is in overload state. It represents the percentage of the cell admission control threshold of downlink. The smaller this parameter is, the earlier downlink MBDR algorithm of inter frequency goes into overload state. When cell load is higher than the product of downlink cell admission control threshold and this parameter, and is lower than the downlink cell admission control threshold, downlink MBDR algorithm of inter frequency is in overload state. GUI Value Range: 0~100 Actual Value Range: 0~100 Unit: None Default Value: 80



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InterFreqMeasQuantity

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Meaning: Measurement quantity used in measurement-based inter-frequency measurement in event (2C) triggered or periodical reporting mode. - CPICH: Common Pilot Channel - Ec/No: Signal-to-Noise Ratio - RSCP: Received Signal Code Power - CPICH_Ec/No: to use the Ec/No measurement quantity for event 2C or Inter-Frequency periodical measurement. The physical unit is dB. - CPICH_RSCP: to use the RSCP measurement quantity for event 2C or Inter-Frequency periodical measurement. The physical unit is dBm. - BOTH:both quantities of the target cell must be satisfied when performing the handover judgement.Valid when the Inter-Frequency measurement chooses PERIODICAL_REPORTING Mode. Recommended value (default value): BOTH(PERIODICAL_REPORTING Mode), CPICH_RSCP(EVENT_TRIGGER Mode) GUI Value Range: CPICH_EC/NO, CPICH_RSCP, BOTH Actual Value Range: CPICH_EC/NO, CPICH_RSCP, BOTH Unit: None Default Value: CPICH_EC/NO



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InterFreqReportMode

BSC6900

ADD UCELLINTERFREQHOCOV(Optional) MOD UCELLINTERFREQHOCOV(Optional)

Meaning: Inter-frequency measurement report mode. If this parameter is set to PERIODICAL_REPORTING, measurement reports are periodically reported. If this parameter is set to EVENT_TRIGGER, measurement reports are reported by triggering the event. There are two inter-frequency handover report modes in the RNC, namely, event-triggered report and periodical report. The report mode is selected by setting the inter-frequency report mode switch that is RNC-oriented. Event-triggered report mode In this mode, event 2B is used to decide whether to trigger inter-frequency handover. This prevents the ping-pong handover (The quality of the currently used frequency is lower than the absolute threshold "used frequency quality threshold", and the quality of the unused frequency is higher than another absolute threshold "target frequency trigger threshold"). Event 2B cannot change from event-triggered mode to periodical mode. When event-triggered measurement report mode is selected, Ec/No and RSCP are both used as the measurement quantity for inter-frequency measurement.The advantage of event-triggered report mode is that the signaling transmission and processing load are saved. Comparing the signal quality between intra-frequency and inter-frequency handovers, the ping-pong effect in handover is prevented to some extent. The disadvantage of event-triggered report mode is that the event is reported only once and cannot be changed to periodical mode. For the cell-oriented algorithm parameters, each time when the best cell is updated, the inter-frequency measurement parameters should be updated accordingly. Periodical report mode In this mode, event 2D/2F is used to start and stop the compressed mode, and to periodically report the inter-frequency cell measurement result in compressed mode. When the cell quality reported by the UE is higher than the absolute threshold plus hysteresis, the triggering delay timer is started. If the conditions are always met before the timer expires, the inter-frequency handover is started after the timer expires. If the handover fails, the handover decision is performed, according to the periodical inter-frequency measurement report. The advantage of the periodical measurement report mode is that it can repeatedly perform direct retry on the same cell when the handover fails, and that the following algorithms can be flexibly developed. For the cell-oriented algorithm parameters, the UE need not be informed through signaling but the cell need be updated only when the handover decision is performed in the RNC. The disadvantage of the periodical measurement report mode is that it requires large amount of signaling and increases the load on the air interface and for signaling processing. As for the impact on network performance,the two



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measurement report modes have both advantages and disadvantages. Currently, the traditional periodical report mode is preferred. GUI Value Range: PERIODICAL_REPORTING(Periodical reporting), EVENT_TRIGGER(Event trigger) Actual Value Range: PERIODICAL_REPORTING, EVENT_TRIGGER Unit: None Default Value: PERIODICAL_REPORTING

InterFreqUlMbdrTrigThreshold

BSC6900


Meaning: This parameter is the relative threshold of cell for judging whether uplink MBDR algorithm of inter frequency is in overload state. It represents the percentage of the cell admission control threshold of uplink. The smaller this parameter is, the earlier uplink MBDR algorithm of inter frequency goes into overload state. When cell load is higher than the product of uplink cell admission control threshold and this parameter, and is lower than the uplink cell admission control threshold, uplink MBDR algorithm of inter frequency is in overload state. GUI Value Range: 0~100 Actual Value Range: 0~100 Unit: None Default Value: 80



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InterRatActiveType

BSC6900

ADD UCELLMBDRINTERRAT(Optional) MOD UCELLMBDRINTERRAT(Optional)

Meaning: MBDR switch GUI Value Range: CSAMR_INTERRAT(CS AMR inter-RAT switch) Actual Value Range: CSAMR_INTERRAT Unit: None Default Value: None

InterRatDlMbdrTrigThreshold

BSC6900


Meaning: This parameter is the relative threshold of cell for judging whether downlink MBDR algorithm of inter RAT is in overload state. It represents the percentage of the cell admission control threshold of downlink. The smaller this parameter is, the earlier downlink MBDR algorithm of inter RAT goes into overload state. When cell load is higher than the product of downlink cell admission control threshold and this parameter, and is lower than the downlink cell admission control threshold, downlink MBDR algorithm of inter RAT is in overload state. GUI Value Range: 0~100 Actual Value Range: 0~100 Unit: None Default Value: 80



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InterRATHOThd BSC6900


Meaning: Quality requirement for the inter-RAT cell during an inter-RAT handover with CS domain services. This parameter is used to set measurement control on the event 3C. The event 3C is triggered when the signal quality of the target frequency is above this threshold. Note that the value 0 indicates that the physical value is smaller than -110 dBm. If the periodical report mode is used, the inter-RAT handover decision thresholds are used for the assessment of inter-RAT coverage handover, namely as Tother_RAT in the following formulas. The inter-RAT handover decision thresholds are the absolute thresholds (RSSI) of inter-RAT cell quality for the inter-RAT handover decision. If the quality of another RAT in the inter-RAT measurement report meets the following condition: Mother_RAT + CIO >= Tother_RAT + H/2 the system starts the trigger timer and implements the handover decision after timeout. If the quality of the preceding RAT meets the following condition before timeout: Mother_RAT + CIO < Tother_RAT - H/2 The system stops the timer, and the RNC waits for another inter-RAT measurement report. In which, Mother_RAT indicates the measurement result of the GSM RSSI; Tother_RAT indicates the inter-RAT handover decision threshold; Cell Individual Offset (CIO) indicates the offset of the inter-RAT cell; H represents the hysteresis. Hysteresis can reduce wrong decisions caused by signal jitters. The sensitivity of a GSM mobile phone is -102 dBm, so the outdoor reception level should not be lower than -90 dBm, considering a margin of 3 dB for compensation of fast fading, 5 dB for compensation of slow fading, 2 dB for compensation of interference noise, and 2 dB for compensation of ambient noise. The values of inter-RAT handover decision thresholds vary with the handover policy. To have UEs hand over only to the GSM cells with high quality, you can set the inter-RAT handover decision threshold to a comparatively high value, for example -85 dBm. GUI Value Range: 0~63 Actual Value Range: lower than -110, -110~-48(Actual value meets the condition: Actual Value = GUI Value - 111) Unit: dBm Default Value: 21



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InterRATPeriodReportInterval

BSC6900

ADD UCELLINTERRATHOCOV(Optional) MOD UCELLINTERRATHOCOV(Optional)

Meaning: Interval that the UE reports inter-RAT measurement results to the RNC. This parameter specifies the interval that the UE sends inter-RAT measurement results to the RNC in periodical reporting mode. It is not recommended that this parameter is set to NON_PERIODIC_REPORT since the UE behavior may be unknown. The GSM RSSI measurement period is 480 ms. Therefore, the inter-RAT periodical reporting interval should be longer than 480 ms. If the periodical reporting interval is excessively high, the handover decision time will be long, and handovers will be slow. The adjustment should be made according to the configured GSM RSSI measurement compressed mode sequence. According to the current configured GSM RSSI measurement compressed mode sequence, the RSSI measurement of eight GSM cells can be finished in 480 ms. Therefore, the RSSI measurement of 16 GSM cells can be finished in 1000 ms. According to 3GPP specifications, the number of inter-RAT neighboring cells should not exceed 32. Therefore, the parameter value can be set to 2000 ms if the number of neighboring GSM cells exceeds 16. The setting of this parameter has impact on the Uu signaling traffic. If the period is too short and the reporting frequency is too high, the RNC may have high load in processing signaling. If the period is too long, the network cannot detect the signal changes in time, which may delay the inter-RAT handover and thus cause call drops. GUI Value Range: NON_PERIODIC_REPORT(Non periodical reporting), D250~1 D500~2 D1000~3 D2000~4 D3000~5 D4000~6 D6000~7 D8000~8 D12000~9 D16000~10 D20000~11 D24000~12 D28000~13 D32000~14 D64000 Actual Value Range: NON_PERIODIC_REPORT, 250, 500, 1000, 2000, 3000, 4000, 6000, 8000, 12000, 16000, 20000, 24000, 28000, 32000, 64000 Unit: ms Default Value: D1000



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InterRatReportMode

BSC6900

ADD UCELLINTERRATHOCOV(Optional) MOD UCELLINTERRATHOCOV(Optional)

Meaning: Inter-RAT measurement reporting mode. When PERIODICAL_REPORTING is selected, the periodical reporting is used for inter-RAT measurement. When EVENT_TRIGGER is selected, the event-triggered reporting is used for inter-RAT measurement. The RNC provides two inter-RAT measurement reporting modes, event-triggered reporting and periodical reporting. Event-triggered reporting To avoid the ping-pong effect before and after the inter-RAT handover, use event 3A (quality of the currently used frequency is lower than the absolute threshold and the signal level of the GSM cell is higher than another absolute threshold) as the triggering event that determines the inter-RAT handover. To improve the handover success rate, the BSIC of the GSM cell whose event 3A needs to be triggered must be decoded correctly by the UE. The reporting mode of event 3A is not changed from event-triggered reporting to periodical reporting. Therefore, no handover re-attempt is made when the handover fails unless event 3A is triggered in this cell again. The advantage of event-triggered reporting is that the signaling transmission and processing load are saved. Comparing the signal quality between intra-frequency and inter-frequency handovers, the ping-pong effect in handover is prevented to some extent. The drawback of event-triggered reporting is that the event is reported only once and cannot be changed to periodical reporting. For the cell-oriented algorithm parameters, each time when the best cell is updated, the inter-frequency measurement parameters should be updated accordingly. Periodical reporting When the quality of the GSM cell reported by the UE meets the criteria for inter-RAT handover, the delay trigger timer is started. If the quality of the GSM cell always meets the criteria for inter-RAT handover before timeout, the inter-RAT handover is triggered after the delay trigger timer expires. For the GSM cell whose BSIC can be decoded correctly, a shorter delay trigger time should be set to indicate the high priority attribute of the GSM cell. For the GSM cell whose BSIC is not verified, a longer delay trigger time should be set to indicate the low priority attribute of the GSM cell. In this manner, the BSIC can be decoded faster. If the handover fails, the handover re-attempt is made again according to the periodical inter-RAT measurement report. The advantage of periodical reporting is that it can be used for repeated handover re-attempts on the same cell when the handover fails, and that subsequent algorithms can be flexibly developed. In addition, for the cell-oriented algorithm parameters, the RNC updates the parameters when making internal handover decision and the system needs not to inform the UEs of the parameter change through signaling messages after the handovers. The drawback of periodical reporting is that it requires large amount of signaling and



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increases the load on the air interface and for signaling processing. The two reporting modes have both advantage and drawback. Currently, the traditional periodical reporting mode is preferred. GUI Value Range: PERIODICAL_REPORTING(Periodical reporting), EVENT_TRIGGER(Event trigger) Actual Value Range: PERIODICAL_REPORTING, EVENT_TRIGGER Unit: None Default Value: PERIODICAL_REPORTING

InterRatUlMbdrTrigThreshold

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Meaning: This parameter is the relative threshold of cell for judging whether uplink MBDR algorithm of inter RAT is in overload state. It represents the percentage of the cell admission control threshold of uplink. The smaller this parameter is, the earlier uplink MBDR algorithm of inter RAT goes into overload state. When cell load is higher than the product of uplink cell admission control threshold and this parameter, and is lower than the uplink cell admission control threshold, uplink MBDR algorithm of inter RAT is in overload state. GUI Value Range: 0~100 Actual Value Range: 0~100 Unit: None Default Value: 80



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LdbDRDchoice BSC6900


Meaning: Whether load balancing DRD is based on power or on user number. - Power: Power(Downlink none-HSDPA power is used for DCH services, and downlink HSDPA guarantee power is used for HSDPA services) will be applied to the load balancing DRD algorithm. - UserNumber: User number(Downlink R99 equivalent user number is used for DCH services, and downlink HSDPA user number is used for HSDPA services) will be applied to the load balancing DRD algorithm. GUI Value Range: Power, UserNumber Actual Value Range: Power, UserNumber Unit: None Default Value: UserNumber

LdbDRDLoadRemainThdDCH

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Meaning: Downlink load threshold to trigger load balancing DRD for DCH services. The load balancing DRD will be triggered only when the downlink remnant non-H power or remnant R99 equivalent user number of the cell is less than this threshold. GUI Value Range: 0~100 Actual Value Range: 0~100 Unit: % Default Value: 35

LdbDRDLoadRemainThdHSDPA

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Meaning: Downlink load threshold to trigger load balancing DRD for HSDPA services. The load balancing DRD will probably be triggered only when the downlink remnant HSDPA guarantee power or remnant HSDPA user number of the cell is less than this threshold. GUI Value Range: 0~100 Actual Value Range: 0~100 Unit: % Default Value: 100

LdbDRDOffsetDCH

BSC6900

SET UDRD(Optional)

Meaning: Threshold of remnant load offset between the current cell and the target cell when load balancing DRD is applied to DCH users. Only when the remnant load offset reaches this threshold can a neighboring cell be selected as a candidate DRD cell for DCH users. If "Load Balancing DRD Choice" is set to Power, additional condition should also be satisfied, that is, total power remnant difference between the current cell and target cell must be less than "Load Balance DRD Total Power Protect Threshold"; if "Load Balancing DRD Choice" is set to UserNumber, additional condition is not needed. GUI Value Range: 0~100 Actual Value Range: 0~100 Unit: %



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Default Value: 10

LdbDRDOffsetHSDPA

BSC6900

SET UDRD(Optional)

Meaning: Threshold of remnant load offset between the current cell and the target cell when load balancing DRD is applied to HSDPA users. Only when the remnant load offset reaches this threshold can a neighboring cell be selected as a candidate DRD cell for HSDPA users. If "Load Balancing DRD Choice" is set to Power, additional condition should also be satisfied, that is, total power remnant difference between the current cell and target cell must be less than "Load Balance DRD Total Power Protect Threshold"; if "Load Balancing DRD Choice" is set to UserNumber, additional condition is not needed. GUI Value Range: 0~100 Actual Value Range: 0~100 Unit: % Default Value: 10

LdbDRDSwitchDCH

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Meaning: Whether the load balancing DRD algorithm is applied to DCH services. - ON: The load balancing DRD algorithm will be applied. - OFF: The load balancing DRD algorithm will not be applied. GUI Value Range: ON, OFF Actual Value Range: ON, OFF Unit: None Default Value: OFF



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LdbDRDSwitchHSDPA

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Meaning: Whether the load balancing DRD algorithm is applied to HSDPA services. - ON: The load balancing DRD algorithm will be applied. - OFF: The load balancing DRD algorithm will not be applied. GUI Value Range: ON, OFF Actual Value Range: ON, OFF Unit: None Default Value: OFF

LdbDRDTotalPwrProThd

BSC6900

SET UDRD(Optional)

Meaning: Threshold of the total downlink remnant power difference between the current cell and the target cell when load balancing DRD is applied and the "Load Balancing DRD Choice" parameter is set to Power. Only when the total downlink remnant power difference is less than this threshold can a neighboring cell be selected as a candidate DRD cell. The other condition is that remnant load offset reaches the threshold defined by the parameter of "Load Balance DRD Offset for DCH" or "Load Balance DRD Offset for HSDPA". GUI Value Range: 0~100 Actual Value Range: 0~100 Unit: % Default Value: 30

MaxAttNum BSC6900


Meaning: The maximum number of attempts to perform inter-freq handovers This parameter specifies the maximum number of attempts for the RNC to perform inter-freq handover after inter-freq handover failure. The handover attempts should involve the cells that have not been tried but satisfy the handover conditions. GUI Value Range: 0~3 Actual Value Range: 0~3 Unit: None Default Value: 1

MaxHsdpaUserNum

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Meaning: Maximum number of users supported by the HSDPA channel. The user in this parameter refers to the user with services on the HSDPA channel, regardless of the number of RABs carried on the HSDPA channel. Maximum HSDPA user number cannot exceed the HSDPA capability of the NodeB product, In practice, the value can be set based on the cell type and the richness of the available HSDPA power and code resources. GUI Value Range: 0~128 Actual Value Range: 0~128 Unit: None Default Value: 64



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MBDRFlag BSC6900


Meaning: Whether the cell supports the measure-based directed retry (MBDR) algorithm. The value TRUE indicates that the cell supports the MBDR algorithm, and the value FALSE indicates that the cell does not support the MBDR algorithm. GUI Value Range: FALSE(Do not send), TRUE(Send) Actual Value Range: FALSE, TRUE Unit: None Default Value: False

MBDRPrio BSC6900


Meaning: Priority of a MBDR cell. This parameter is valid only when the "MBDRFlag" parameter is set to TRUE. It indicates the tiptop priority when the value is set to 0, and the lowest priority when the value is set to 15. The higher the priority, the easier it is for the MBDR cell to be delivered as the measurement object and the easier to be selected to the handover target cell when there are many of cells meet the quality condition. Attention, when there does not have cell meet the quality condition base on the MBDR measurement result, if there exists a cell which has the priority of 0, and the type of the measurement report is periodic, then it can be selected to blind handover target cell. GUI Value Range: 0~15 Actual Value Range: 0~15 Unit: None Default Value: 0

MIMO64QAMorDCHSDPASwitch

BSC6900

SET UFRC(Optional)

Meaning: This parameter specifies the priority of MIMO_64QAM or DC-HSDPA. According to different protocols, the following situations may occur: MIMO and DC-HSDPA cannot be used together; both 64QAM and DC-HSDPA are supported, but cannot be used together. In this case, "MIMO64QAMorDCHSDPASwitch" is used to configure the priorities of the features. When the parameter assigns preference for MIMO over DC-HSDPA, then the priority of 64QAM will be higher than for DC-HSDPA. When the DC-HSDPA is assigned preference over MIMO, then the priority of DC-HSDPA will be higher than for 64QAM. GUI Value Range: MIMO_64QAM, DC_HSDPA Actual Value Range: MIMO_64QAM, DC_HSDPA Unit: None Default Value: DC_HSDPA



6-20


MIMOor64QAMSwitch

BSC6900

SET UFRC(Optional)

Meaning: According to the R8 protocol, MIMO and 64QAM can be used together. When the condition is not met, for example the cell does not support the features, MIMO may be not used together with 64QAM. In this case, "MIMOor64QAMSwitch" is used to determine whether MIMO or 64QAM is preferentially used. GUI Value Range: MIMO, 64QAM Actual Value Range: MIMO, 64QAM Unit: None Default Value: MIMO

NBMDlCacAlgoSelSwitch

BSC6900

ADD UCELLALGOSWITCH(Mandatory) MOD UCELLALGOSWITCH(Optional)

Meaning: The algorithms with the above values represent are as follow: ALGORITHM_OFF: Disable downlink call admission control algorithm. ALGORITHM_FIRST: The load factor prediction algorithm will be used in downlink CAC. ALGORITHM_SECOND: The equivalent user number algorithm will be used in downlink CAC. ALGORITHM_THIRD: The loose call admission control algorithm will be used in downlink CAC. GUI Value Range: ALGORITHM_OFF, ALGORITHM_FIRST, ALGORITHM_SECOND, ALGORITHM_THIRD Actual Value Range: ALGORITHM_OFF, ALGORITHM_FIRST, ALGORITHM_SECOND, ALGORITHM_THIRD Unit: None Default Value: None

NBMUlCacAlgoSelSwitch

BSC6900

ADD UCELLALGOSWITCH(Mandatory) MOD UCELLALGOSWITCH(Optional)

Meaning: The algorithms with the above values represent are as follow: ALGORITHM_OFF: Disable uplink call admission control algorithm. ALGORITHM_FIRST: The load factor prediction algorithm will be used in uplink CAC. ALGORITHM_SECOND: The equivalent user number algorithm will be used in uplink CAC. ALGORITHM_THIRD: The loose call admission control algorithm will be used in uplink CAC. GUI Value Range: ALGORITHM_OFF, ALGORITHM_FIRST, ALGORITHM_SECOND, ALGORITHM_THIRD Actual Value Range: ALGORITHM_OFF, ALGORITHM_FIRST, ALGORITHM_SECOND, ALGORITHM_THIRD Unit: None Default Value: None



6-21


PrdReportInterval

BSC6900

ADD UCELLINTERFREQHOCOV(Optional) MOD UCELLINTERFREQHOCOV(Optional)

Meaning: Interval between periodic reporting for the inter-frequency handover. In periodic reporting mode, the inter-frequency handover attempts is reported at the preset interval. It is not recommended that this parameter be set to "NON_PERIODIC_REPORT" since the UE behavior may be unknown. This parameter has impact on the Uu signaling flow. If the interval is too short and the frequency is too high, the RNC may have high load when processing signaling. If the interval is too long, the network cannot detect the signal changes in time. This may delay the inter-frequency handover, thus causing call drops. GUI Value Range: NON_PERIODIC_REPORT(Non periodical reporting), D250~1 D500~2 D1000~3 D2000~4 D3000~5 D4000~6 D6000~7 D8000~8 D12000~9 D16000~10 D20000~11 D24000~12 D28000~13 D32000~14 D64000 Actual Value Range: NON_PERIODIC_REPORT, 250, 500, 1000, 2000, 3000, 4000, 6000, 8000, 12000, 16000, 20000, 24000, 28000, 32000, 64000 Unit: ms Default Value: D500

PrdReportInterval

BSC6900


Meaning: Interval between sending of periodic measurement reports. This parameter has impact on the Uu signaling flow. If this parameter is set to a small value, the RNC may have high load when processing signaling. If this parameter is set to a great value, the network cannot detect the signal changes in time. This may delay the inter-frequency handover. GUI Value Range: D250, D500, D1000, D2000, D3000, D4000, D6000, D8000, D12000, D16000, D20000, D24000, D28000, D32000, D64000 Actual Value Range: 250, 500, 1000, 2000, 3000, 4000, 6000, 8000, 12000, 16000, 20000, 24000, 28000, 32000, 64000 Unit: ms Default Value: D3000



6-22


RetryCapability BSC6900

SET UFRC(Optional)

Meaning: This parameter specifies which HSPA technologies can be retried by UEs. When the HSPA technologies are selected and currently UE is not using them, RNC will initiate these HSPA technologies retry for UE. GUI Value Range: SRB_OVER_HSDPA, SRB_OVER_HSUPA, TTI_2MS, MIMO, 64QAM, DL_L2_ENHANCE, DTX_DRX, HSSCCH_LESS_OPERATION, MIMO_64QAM, DC_HSDPA, UL_L2_ENHANCE, UL_16QAM Actual Value Range: SRB_OVER_HSDPA, SRB_OVER_HSUPA, TTI_2MS, MIMO, 64QAM, L2_ENHANCE, DTX_DRX, HSSCCH_LESS_OPERATION, MIMO_64QAM, DC_HSDPA, UL_L2_ENHANCE, UL_16QAM Unit: None Default Value: None

ServiceDiffDrdSwitch

BSC6900


Meaning: Whether the service steering DRD algorithm is applied. GUI Value Range: ON, OFF Actual Value Range: ON, OFF Unit: None Default Value: OFF

TargetFreqThdEcN0

BSC6900


Meaning: Ec/No Threshold for the target cell. This parameter is used to estimate the signal quality of the periodic reports. The DRD is triggered only when the signal quality of the target cell is higher than this parameter. If this parameter is set to a greater value, it is difficult for subscribers to re-access another cell with a higher priority; however, the re-attempt success rate is high. If this parameter is set to a lower value, it is easy for subscribers to re-access another cell with a higher priority; however, the re-attempt success rate however is low. Note: The threshold can be reached only when RSCP and Ec/No of the target cell are above the RSCP and EcNo that are set in the command.In order to increase the successful rate of handover, inner protection mechanism keep Ec/No of target cell larger than -16. GUI Value Range: -24~0 Actual Value Range: -24~0 Unit: dB Default Value: -12



6-23


TargetFreqThdRscp

BSC6900


Meaning: RSCP Threshold for the target cell. This parameter is used to estimate the signal quality of the periodic reports.The DRD is triggered only when the signal quality of the target cell is higher than this parameter. If this parameter is set to a greater value, it is difficult for subscribers to re-access another cell with a higher priority; however, the re-attempt success rate is high. If this parameter is set to a lower value, it is easy for subscribers to re-access another cell with a higher priority; however, the re-attempt success rate however is low. Note: The threshold can be reached only when RSCP and Ec/No of the target cell are above the RSCP and Ec/No that are set in the command. GUI Value Range: -115~-25 Actual Value Range: -115~-25 Unit: dBm Default Value: -92

TrigTime2C BSC6900

ADD UCELLINTERFREQHONCOV(Optional) MOD UCELLINTERFREQHONCOV(Optional)

Meaning: Interval time between detection of event 2C and sending of the measurement report. The value of this parameter is associated with slow fading. If this parameter is set to a greater value, the probability of incorrect decision becomes low; however, the handover algorithm becomes slow in responding to signal change. The emulation results show that setting this interval can effectively reduce the average number of handovers and the number of incorrect handovers, preventing unnecessary handovers. In addition, the UE at different rates may react differently to the same interval. For the fast-moving UE, the call drop rate is more sensitive to this interval, whereas, for the slow-moving UE, the call drop rate is less sensitive to this interval. Therefore, for the cell with most of the fast-moving UEs, this parameter can be set to a smaller value, whereas for the cell with most of the slow-moving UEs, this parameter can be set to a greater value. The value of this parameter can be adjusted according to the actual network statistics. GUI Value Range: D0, D10, D20, D40, D60, D80, D100, D120, D160, D200, D240, D320, D640, D1280, D2560, D5000 Actual Value Range: 0, 10, 20, 40, 60, 80, 100, 120, 160, 200, 240, 320, 640, 1280, 2560, 5000 Unit: ms Default Value: D640



6-24


TrigTime3C BSC6900

ADD UCELLINTERRATHONCOV(Optional) MOD UCELLINTERRATHONCOV(Optional)

Meaning: Interval time between detection of event 3C and sending of the measurement report. The value of this parameter is associated with the slow fading. If this parameter is set to a greater value, the probability of incorrect handover decision becomes low; however, the handover algorithm becomes slow in responding to signal change. If this parameter is set to a smaller value, the handover algorithm becomes fast in responding to signal change; however, the probability of incorrect decision becomes high. The emulation result shows that the hysteresis setting can effectively reduce the average number of handovers and the number of incorrect handovers, thus preventing unnecessary handovers. The emulation result also shows that the UE at different data rates may react differently to the delay for triggering the event. For the fast-moving UE, the call drop rate is more sensitive to the delay, whereas, for the slow-moving UE, the call drop rate is less sensitive to the delay. This can also reduce ping-pong handovers and incorrect handovers. Therefore, for the cell where most UEs are in fast movement, this parameter can be set to a smaller value, whereas for the cell where most UEs are in slow movement, this parameter can be set to a greater value. The value of this parameter can be adjusted according to the actual network statistics. The inter-frequency measurement reporting period is 480 ms. Therefore, the trigger delay time shorter than 480 ms is invalid. If the parameter is set to a larger value, handover is unlikely to be triggered. However, call drops may increase as the parameter value increases. GUI Value Range: D0, D10, D20, D40, D60, D80, D100, D120, D160, D200, D240, D320, D640, D1280, D2560, D5000 Actual Value Range: 0, 10, 20, 40, 60, 80, 100, 120, 160, 200, 240, 320, 640, 1280, 2560, 5000 Unit: ms Default Value: D640

ULLdbDRDLoadRemainThdDcHSDPA

BSC6900


Meaning: This parameter specifies the threshold of triggering the uplink load balance for DC-HSDPA traffic. If the remaining number of equivalent users in the uplink is less than the value of this parameter, uplink load balance for DC-HSDPA traffic is triggered. GUI Value Range: 0~100 Actual Value Range: 0~100 Unit: % Default Value: 25



6-25


ULLdbDRDOffsetDcHSDPA

BSC6900

SET UDRD(Optional)

Meaning: If the difference of the remaining number of equivalent users in the uplink between the target cell and the serving cell is greater than the value of this parameter, the target cell meets one of the qualifications to be the candidate cell for directed retry. GUI Value Range: 0~100 Actual Value Range: 0~100 Unit: % Default Value: 10

ULLdbDRDSwitchDcHSDPA

BSC6900


Meaning: This parameter specifies whether to enable the uplink load balance for DC-HSDPA traffic. The uplink load balance is performed on the basis of the equivalent number of users. GUI Value Range: ON, OFF Actual Value Range: ON, OFF Unit: None Default Value: OFF

UlNonCtrlThdForAMR

BSC6900


Meaning: The percentage of the conversational non-AMR service threshold to the 100% uplink load. It is applicable to algorithm 1 and algorithm 2. The parameter is used for controlling the non-AMR service admission. That is, when a non-AMR service is accessing, the RNC evaluates the measurement value of the uplink load after the service is accessed. If the UL load of a cell is higher than this threshold after the access of a non-AMR speech service, this service will be rejected. If the UL load of a cell will not be higher than this threshold, this service will be admitted. The UL load factor thresholds include parameters of [UL threshold of Conv non_AMR service], [UL handover access threshold] and [UL threshold of other services]. The four parameters can be used to limit the proportion between the conversational service, handover user and other services in a specific cell, and to guarantee the access priority of the conversational non-AMR service. GUI Value Range: 0~100 Actual Value Range: 0~1, step:0.01 Unit: % Default Value: 75



6-26


UlNonCtrlThdForNonAMR

BSC6900


Meaning: The percentage of the conversational non-AMR service threshold to the 100% uplink load. It is applicable to algorithm 1 and algorithm 2. The parameter is used for controlling the non-AMR service admission. That is, when a non-AMR service is accessing, the RNC evaluates the measurement value of the uplink load after the service is accessed. If the UL load of a cell is higher than this threshold after the access of a non-AMR speech service, this service will be rejected. If the UL load of a cell will not be higher than this threshold, this service will be admitted. The UL load factor thresholds include parameters of [UL threshold of Conv non_AMR service], [UL handover access threshold] and [UL threshold of other services]. The four parameters can be used to limit the proportion between the conversational service, handover user and other services in a specific cell, and to guarantee the access priority of the conversational non-AMR service. GUI Value Range: 0~100 Actual Value Range: 0~1, step:0.01 Unit: % Default Value: 75

UlNonCtrlThdForOther

BSC6900


Meaning: The percentage of other service thresholds to the 100% uplink load. The services refer to other admissions except the conversational AMR service, conversational non-AMR service, and handover scenarios. It is applicable to algorithm 1 and algorithm 2. The parameter is used for controlling other service admissions. That is, when a service is accessing, the RNC evaluates the measurement value of the uplink load after the service is accessed. If the UL load of a cell is higher than this threshold after the access of a service, this service will be rejected. If the UL load of a cell will not be higher than this threshold, this service will be admitted. The UL load factor thresholds include parameters of [UL threshold of Conv non_AMR service], [UL handover access threshold] and [UL threshold of other services]. The four parameters can be used to limit the proportion between the conversational service, handover user and other services in a specific cell, and to guarantee the access priority of other services. GUI Value Range: 0~100 Actual Value Range: 0~1, step:0.01 Unit: % Default Value: 60



6-27


UserPercentage BSC6900


Meaning: The ratio of the users which could launch the handover to inter-RAT neighbour cell. When the parameter is ALL_USER, it means all of the users could be handover to the inter-RAT neighbour cell. When the parameter is HALF, it means only 1/2 of the users could be handover to the inter-RAT neighbour cell. When the parameter is THIRD, it means only 1/3 of the users could be handover to the inter-RAT neighbour cell. When the parameter is QUARTER, it means only 1/4 of the users could be handover to the inter-RAT neighbour cell. GUI Value Range: ALL_USER(All User), HALF(Half), THIRD(THIRD), QUARTER(QUARTER) Actual Value Range: ALL_USER, HALF, THIRD, QUARTER Unit: None Default Value: ALL_USER

WCDMA RAN Directed Retry Decision 7 Counters


7-1

7 Counters

For details, see the BSC6900 UMTS Performance Counter Reference.

WCDMA RAN Directed Retry Decision 8 Glossary


8-1

8 Glossary

For the acronyms, abbreviations, terms, and definitions, see the Glossary.

Glossary.htm

WCDMA RAN Directed Retry Decision 9 Reference Documents


9-1

9 Reference Documents [1] Call Admission Control Feature Parameter Description

[2] Load Control Feature Parameter Description

[3] BSC6900 UMTS Performance Counter Reference

Call%20Admission%20Control.htm

Load%20Control.htm

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