WCDMA R11 Feature Parameter Description_Handover

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Huawei Proprietary and Confidential

Copyright Huawei Technologies Co., Ltd

RAN

HandoverParameter Description

Issue 02

Date 2009-06-30


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Huawei Proprietary and Confidential


Copyright Huawei Technologies Co., Ltd. 2009. All rights reserved.

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

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

All other trademarks and trade names mentioned in this document are the property of their respectiveholders.

Notice

The purchased products, services and features are stipulated by the contract made between Huawei andthe customer. All or part of the products, services and features described in this document may not be

within the purchase scope or the usage scope. Unless otherwise specified in the contract, all statements,information, and recommendations in this document are providedAS IS without warranties, guarantees

or representations of any kind, either express or implied.

The information in this document is subject to change without notice. Every effort has been made in thepreparation of this document to ensure accuracy of the contents, but all statements, information, andrecommendations in this document do not constitute the warranty of any kind, express or implied.

Huawei Technologies Co., Ltd.

Address: Huawei Industrial Base

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iii

Contents

1 Introduction to This Document ............................................................................................... 1-1

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

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

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

2 Overview of Handover .............................................................................................................. 2-1

2.1 Handover Types ............................................................. ................................................................. ............... 2-1

2.2 Intra-Frequency Handover ...................... ................................................................. ..................................... 2-2

2.3 Inter-Frequency Handover ...................... ................................................................. ..................................... 2-4

2.4 Inter-RAT Handover (3G to 2G) ........................ ................................................................. .......................... 2-5

2.4.1 Inter-RAT Handover Introduction ........................................................................................................ 2-5

2.4.2 Rules for Enabling 3G-to-2G Handover ............................................................................... ............... 2-6

3 Intra-Frequency Handover Algorithms ................................................................................. 3-1

3.1 Intra-Frequency Handover Procedure ................................................................................. .......................... 3-1

3.2 Intra-Frequency Handover Measurement ...................................................................................................... 3-1

3.2.1 Intra-Frequency Handover Measurement Quantities .................................................................... ....... 3-2

3.2.2 Intra-Frequency Handover Measurement Events ....................................................... .......................... 3-2

3.2.3 Intra-Frequency Handover Neighboring Cell Combination Algorithm ..................... .......................... 3-9

3.3 Intra-Frequency Handover Decision and Execution ..... .............................................................. ................ 3-10

3.3.1 Decision and Execution ............................ ................................................................. ........................ 3-10

3.3.2 Rate Reduction After an SHO Failure ............................................................. ................................... 3-12

3.4 Intra-Frequency Handover of HSDPA .................................... ............................................................... ..... 3-15

3.4.1 Decision and Execution of Intra-Frequency Handover ...................................................................... 3-15

3.4.2 F-DPCH Handover Protection ........................................................................ ................................... 3-16

3.5 Intra-Frequency Handover of HSUPA .................................... ............................................................... ..... 3-17

3.5.1 Decision and Execution of Intra-Frequency Handover ...................................................................... 3-17

3.5.2 Handover Between E-DCHs of 10 ms TTI and 2 ms TTI ................................................................ .. 3-20

3.6 Signaling Procedures for Intra-Frequency Handover .................................................................................. 3-20

3.6.1 Intra-NodeB Intra-Frequency Soft Handover Signaling Procedure ................................................... 3-20

3.6.2 Intra-RNC Inter-NodeB Intra-Frequency Soft Handover Signaling Procedure ................................. 3-22

3.6.3 Inter-RNC Intra-Frequency Soft Handover Signaling Procedure ...................................................... 3-24

3.6.4 Intra-RNC Inter-NodeB Intra-Frequency Hard Handover Signaling Procedure ................................ 3-26

3.6.5 Inter-RNC Intra-Frequency Hard Handover Signaling Procedure ..................................................... 3-27

4 Inter-Frequency Handover Algorithms ................................................................................. 4-1

4.1 Inter-Frequency Handover Procedure ................ ................................................................. .......................... 4-1


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4.1.1 Coverage- or QoS-based Inter-Frequency and Inter-RAT Handover Procedure .................................. 4-1

4.1.2 Load-based Inter-Frequency Handover Procedure ................................................................ ............... 4-3

4.1.3 Speed-based Inter-Frequency Handover Procedure ...................................................................... ....... 4-3

4.2 Inter-Frequency Handover Measurement ...................................................................................................... 4-5

4.2.1 Inter-Frequency Handover Measurement Switches ................................................... .......................... 4-5

4.2.2 Inter-Frequency Handover Measurement Report Modes ..................................................................... 4-6

4.2.3 Inter-Frequency Handover Measurement Quantity ............................................................... ............... 4-6

4.2.4 Inter-Frequency Handover Measurement Events ....................................................... .......................... 4-7

4.2.5 Inter-Frequency Handover Neighboring Cell Combination Algorithm .............................................. 4-10

4.2.6 Inter-Frequency Handover Compressed Mode ............... .............................................................. ..... 4-10

4.3 Inter-Frequency Handover Decision and Execution...................................... .............................................. 4-12

4.3.1 Coverage- and QoS-based Inter-Frequency Handover Decision and Execution ................................ 4-12

4.3.2 Load-based Inter-Frequency Handover Decision and Execution ....................................................... 4-14

4.3.3 Speed-based Inter-Frequency Handover Decision and Execution ..................................................... 4-15

4.3.4 Blind Handover Decision and Execution Based on Event 1F ............................................................ 4-15

4.3.5 Inter-Frequency Anti-Ping-Pong Algorithm ............................................................... ........................ 4-16

4.3.6 Inter-Frequency Handover Retry ... ................................................................. ................................... 4-16

4.4 Inter-Frequency Handover of HSDPA .......................... ................................................................. ............. 4-16

4.5 Inter-Frequency Handover of HSUPA .......................... ................................................................. ............. 4-19

4.6 Signaling Procedures for Inter-Frequency Handover .................................................................................. 4-21

4.6.1 Inter-Frequency Handover Within One RNC ............................................................. ........................ 4-21

4.6.2 Inter-Frequency Handover Between RNCs ................................................................ ........................ 4-23

5 Inter-RAT Handover Algorithms ............................................................................................ 5-1

5.1 3G-to-2G Handover Procedure .......................... ................................................................. .......................... 5-1

5.1.1 Coverage-based 3G-to-2G Handover Procedure ........................................................ .......................... 5-1

5.1.2 Load-based 3G-to-2G Handover Procedure ............................................................... .......................... 5-1

5.1.3 Service-based 3G-to-2G Handover Procedure ..................................................................................... 5-2

5.1.4 Speed-based 3G-to-2G Handover Procedure ....................................................................................... 5-2

5.2 3G-to-2G Handover Measurement ................................................................ ................................................ 5-3

5.2.1 3G-to-2G Handover Measurement Switches ............................................................. .......................... 5-3

5.2.2 3G-to-2G Handover Measurement Report Modes ............................................................................... 5-3

5.2.3 3G-to-2G Handover Measurement Quantity ................................................................................. ....... 5-35.2.4 3G-to-2G Handover Measurement Events ........................................................................................... 5-4

5.2.5 3G-to-2G Handover Neighboring Cell Combination Algorithms ........................................................ 5-7

5.2.6 3G-to-2G Handover Compressed Mode .............................................. ................................................ 5-7

5.2.7 BSIC Verification Requirements for 2G Cells ................................................................... .................. 5-7

5.3 3G-to-2G Handover Decision and Execution ........................................................... ..................................... 5-7

5.3.1 Coverage and QoS-based UMTS-to-GSM Handover Decision and Execution ................................... 5-7

5.3.2 Load- and Service-based 3G-to-2G Handover Decision and Execution .............................................. 5-8

5.3.3 3G-to-2G Handover Retry ............. ................................................................. ..................................... 5-9

5.3.4 3G-to-2G Multimedia Fallback ............................................................ .............................................. 5-10


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5.3.5 3G-to-2G Handover in the PS Domain with NACC .......................................................................... 5-12

5.4 Inter-RAT Handover of HSDPA ............................................................................................................. ..... 5-12

5.5 Inter-RAT Handover of HSUPA ............................................................................................................. ..... 5-12

5.6 2G-to-3G Handover............................................ ................................................................. ........................ 5-13

5.7 Interoperability Between Inter-RAT Handover and Inter-Frequency Handover ......................................... 5-14

5.8 Signaling Procedures for Inter-RAT Handover ........................ ................................................................. .. 5-14

5.8.1 3G-to-2G Handover in CS Domain ................................................................. ................................... 5-14

5.8.2 3G-to-2G Handover in PS Domain ................................................................. ................................... 5-15

5.8.3 3G-to-2G Handover in Both CS Domain and PS Domain ................................................................. 5-16

5.8.4 2G-to-3G Handover in CS Domain ................................................................. ................................... 5-18

5.8.5 2G-to-3G Handover in PS Domain ................................................................. ................................... 5-19

6 HCS Handover Algorithms ...................................................................................................... 6-1

6.1 HCS Handover Overview ......................................................... ................................................................. .... 6-1

6.2 HCS Handover Phases ....................................... ................................................................. .......................... 6-2

6.2.1 UE Speed Estimation ...................................................................................... ..................................... 6-2

6.2.2 HCS Handover Execution .......................................................... .......................................................... 6-3

6.3 Signaling Procedure of HCS Handover ......................................................... ................................................ 6-4

6.4 Interoperability Between HCS Handover and Other Handovers ............................................................... .... 6-4

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

8 Counters ....................................................................................................................................... 8-1

9 Glossary ....................................................................................................................................... 9-1

10 Reference Documents............................................................................................................ 10-1


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1 Introduction to This Document1.1 Scope

The document describes the handover functional area. It provides an overview of the main

functions and goes into details regarding handover.

1.2 Intended Audience

It is assumed that users of this document are familiar with WCDMA basics and have a

working knowledge of 3G telecommunication.

Personnel working on Huawei products or systems.

System operators who need a general understanding of handover.

1.3 Change HistoryThis 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 handover feature.

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

Document Issues

The document issues are as follows:

02 (2009-06-30)

01 (2009-03-30)

Draft (2009-03-10)

Draft (2009-01-15)

02 (2009-06-30)

This is the document for the second commercial release of RAN11.0.


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02 (2009-06-30)

Compared with 01 (2009-03-30) of RAN11.0, this issue adjusts the structure of the document

01 (2009-03-30)

This is the document for the first commercial issue.

Compared with draft (2009-03-10), this issue optimizes the description.

Draft (2009-03-10)

This is the second draft of the document for RAN11.0.

Compared with draft (2009-01-15), draft (2009-03-10) optimizes the description.

Draft (2009-01-15)

This is the first draft of the document for RAN11.0.

Compared with issue 02 (2008-07-30) of RAN10.0, draft (2009-01-15) incorporates the

following changes:

ChangeType

Change Description Parameter Change

Featurechange

None. The name ofSIGNAL_HO_SWITCH is changed toHO_MC_SIGNAL_SWITCH.

The name ofACT_SET_QUAL_SWITCH is

changed toHO_INTER_FREQ_RPRT_2D2F_SWITCH.

The name ofINTER_FREQ_HHO_SWITCH ischanged toHO_INTER_FREQ_HARD_HO_SWITCH.

The name of

HO_BEYOND_UE_CAP_ADD_TO_MC_SWITC

H is changed toHO_MC_MEAS_BEYOND_UE_CAP_SWITCH.

The function CS Voice

over HSPA is added.

The added parameter is as follows:

CSVoiceoverHSPASuppInd


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ChangeType

Change Description Parameter Change

Editorialchange

TheHandover

Parameter Descriptioncombines the contents

of the following

documents:

Intra-frequencyHandoverDescription

Inter-frequencyHandover

Description

Inter-RAT Handover

Description

HCS HandoverDescription

None.


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2 Overview of HandoverHandover is a basic function of the cellular mobile network. The purpose of handover is toensure that a UE in CELL_DCH state is served continuously when it moves.

The handover functions are classified into the following types:

Intra-frequency handover

Inter-frequency handover

Inter-RAT handover

2.1 Handover TypesFigure 2-1 shows the handovers supported by the Universal Mobile Telecommunications

System (UMTS), which include intra-frequency handover, inter-frequency handover, andinter-RAT handover.


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Figure 2-1Handovers supported by the UMTS

2.2 Intra-Frequency HandoverIntra-frequency handover is of the following two types:

Intra-frequency soft handover: means that multiple radio links are connected to the UE at

the same time.

Intra-frequency hard handover: means that only one radio link is connected to the UE at

the same time.

Intra-Frequency Soft Handover

Intra-frequency soft handover is more commonly used than intra-frequency hard handover.

The types of intra-frequency soft handover are as follows:

Intra-NodeB soft handover (also known as softer handover)

Intra-RNC inter-NodeB soft handover

Inter-RNC soft handover

Intra-frequency soft handover is characterized by the function that the UE can be connected to

multiple Universal Terrestrial Radio Access Network (UTRAN) access points at the same


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time. Addition and/or release of radio links are controlled by the ACTIVE SET UPDATEprocedure.

Table 2-1Differences between soft handover and softer handover

Item Softer Handover Soft Handover

Scenario When the UE is in theoverlapped coverage area ofmultiple neighboring cells of a

NodeB with combined RLs

When the UE communicates

with multiple cells by settingup multiple channels over theUu interface

When the UE is in the overlappedcoverage area of two neighboring cellsof different NodeBs

When the UE communicates with

different cells by setting up multiple

channels over the Uu interface

Uplink signal Using maximum-ratio

combination

Using selection combination

Downlink

signal

Using maximum-ratio

combination

Using maximum-ratio combination

Resource use Occupying less Iub bandwidth Occupying more Iub bandwidth

The HO_INTRA_FREQ_SOFT_HO_SWITCH parameter is used to determine whether to

enable both soft handover and softer handover. By default, this switch is set to ON, indicatingthat both soft handover and softer handover are enabled. After the RNC receives the event 1A,

1B, 1C, or 1D report, it initiates the corresponding soft handover procedure for the UE. For

example, the RNC can add or delete links.

The DivCtrlField parameter indicates whether maximum-ratio combination is enabled in theuplink during softer handover.

Intra-Frequency Hard Handover

Intra-frequency hard handover refers to a handover where all the old radio links are released

before the new radio links are established. Compared with soft handover, intra-frequency hardhandover uses fewer resources.

The scenarios of intra-frequency hard handover are as follows:

No Iur interface is present between RNCs. In this scenario, intra-frequency hardhandover instead of soft handover can be performed between two RNCs.

The Iur interface is congested between RNCs. In this scenario, also intra-frequency hardhandover instead of soft handover can be performed between two RNCs.

There is a high-speed Best Effort (BE) service.

Compared with soft handover, intra-frequency hard handover is used to save downlinkbandwidth for a high-speed BE service.

The intra-frequency soft handover fails and intra-frequency hard handover is allowed.

When intra-frequency soft handover fails because of a congestion problem of the targetcell, the RNC tries an intra-frequency hard handover with a lower service bit rate.

The HO_INTRA_FREQ_HARD_HO_SWITCH parameter is used to determine whether toenable intra-frequency hard handover. By default, this switch is set to ON.


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2.3 Inter-Frequency HandoverInter-frequency handover provides supplementary coverage for inter-frequency cells to share

load with each other and to ensure service continuity.

From the UE point of view, inter-frequency handover is the same as intra-frequency hard

handover, because for both cases, the old connection is released before a new connection isset up.

The types of inter-frequency handover are as follows:

Table 2-2Types of inter-frequency handover

Type Description

Coverage-based

inter-frequency handover

If a moving UE leaves the coverage of the current

frequency, the RNC needs to trigger the coverage-based

inter-frequency handover to avoid call drops.QoS-based inter-frequencyhandover

According to the Link Stability Control Algorithm, theRNC needs to trigger the QoS-based inter-frequency

handover to avoid call drops.

Load-based inter-frequency

blind handover

To balance the load between inter-frequency con-coverage

cells, the RNC chooses some UEs and performs theinter-frequency blind handover according to user priorities

and service priorities.

Speed-based inter-frequency

handover

When the Hierarchical Cell Structure (HCS) applies, the

cells are divided into different layers according to

coverage. The macro cell has a larger coverage and a lowerpriority, whereas the micro cell has a smaller coverage and

a higher priority.

Inter-frequency handover can be triggered by the UE speedestimation algorithm of the HCS. To reduce frequenthandovers, the UE at a higher speed is handed over to a cell

under a larger coverage, whereas the UE at a lower speed ishanded over to a cell under a smaller coverage. For detailed

information, see 6 HCS Handover Algorithms.

The coverage-based inter-frequency measurement and the QoS-based inter-frequency

measurement can coexist.

The InterFreqHOSwitch parameter is used to determine the type of inter-frequencyhandover. According to the switch, the RNC chooses the inter-frequency measurement controlparameters to implement handover measurement based on coverage, QoS, speed, and other

types.

INTER_FREQ_COV: The cell supports coverage-based inter-frequency handover.

INTER_FREQ_COV_NCOV: The cell supports coverage-based and

speed-estimation-triggered inter-frequency handover.

INTER_FREQ_TA: The inter-frequency handover is triggered by HCS traffic absorption.This function itself contains the coverage-based function.


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The HO_INTER_FREQ_HARD_HO_SWITCH parameter is used to determine whether

to allow load-based inter-frequency handover.

For detailed description of QoS-based inter-frequency blind handover switches, see theRateControl Parameter Description.

2.4 Inter-RAT Handover (3G to 2G)

2.4.1 Inter-RAT Handover Introduction

Inter-RAT handover refers to the handover performed between 3G network and 2G network.

The handover causes can be coverage limitation, link stability, or load limitation of the UMTS

network. This document mainly describes the 3G-to-2G handover.

Inter-RAT handover provides continuous coverage, load sharing, and HCS services, which

fully utilizes the existing 2G network resources and thus reduces operator's cost.Based on the handover triggering causes, the 3G-to-2G handover can be categorized as fivetypes, as described in Table 2-3.

Table 2-33G-to-2G handover types

Type Description

Coverage-based

3G-to-2G

handover

The coverage of the 3G network is incontinuous at the initial stage.

On the border of the coverage, the poor signal quality of the 3G

network triggers the 3G-to-2G measurement. If the signal quality ofthe 2G network is good enough and all the services of the UE are

supported by the 2G network, the coverage-based 3G-to-2G handoveris triggered.

QoS-based3G-to-2Ghandover

According to the Link Stability Control Algorithm, the RNC needs totrigger the QoS-based 3G-to-2G handover to avoid call drops.

Load-based3G-to-2G

handover

If the load of the 3G network is heavy and all the RABs of the UE aresupported by the 2G network, the load-based 3G-to-2G handover is

triggered.

Service-based

3G-to-2G

handover

Based on layered services, the traffic of different classes is handed

over to different systems. For example, when an Adaptive Multi Rate

(AMR) speech service is requested, this service can be handed overto the 2G network.


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Type Description

Speed-based

3G-to-2G

handover

When the Hierarchical Cell Structure (HCS) applies, the cells are

divided into different layers according to coverage. The macro cell

has a larger coverage and a lower priority, whereas the micro cell has

a smaller coverage and a higher priority.

The 3G-to-2G handover can be triggered by the UE speed estimationalgorithm of the HCS. To reduce the frequencies of handover, the UE

at a higher speed is handed over to a cell under a larger coverage,whereas the UE at a lower speed is handed over to a cell under a

smaller coverage. For detailed information, see 6 HCS Handover

Algorithms.

Note:

The principles of the 3G-to-2G handover based on HCS speed

estimation are similar to those of inter-frequency handover.

2.4.2 Rules for Enabling 3G-to-2G Handover

Before handover, the RNC checks whether all the preconditions for the 3G-to-2G handoverare met. The preconditions include service handover indicators, service requirements, and

handover rules.

Before deciding the 3G-to-2G handover, the RNC considers 2G cell capability, service

capability and UE capability.

2G cell capability

2G cell capability is configured through the parameter RATCELLTYPE. Thisparameter indicates whether the cell supports the GSM, GPRS, or EDGE.

Service capability

The Required 2G Capability (Req2GCap) specifies the capability of 2G cells requiredby inter-RAT handover. This indicates whether the service is supported by the GSM,

GPRS, or EDGE. For the default value provided by the RNC, see Table 2-6.

UE capability

Upon the reception of the UE capability information message, the RNC decides whetherto start the inter-RAT measurement. The information indicates whether the UE supports

the GSM, GPRS, or EDGE.

The rules for enabling the 3G-to-2G handover are based on the Service Handover

Indicator and the three types of capability. The rules vary according to the types ofinter-RAT handover.

Rules for Enabling Coverage- and QoS-based 3G-to-2G Handover

The RNC initiates the coverage- or QoS-based UMTS-to-GSM handover only when Service

Handover Indicator is set as follows:

HO_TO_GSM_SHOULD_BE_PERFORM

HO_TO_GSM_SHOULD_NOT_BE_PERFORM

The following tables describe the impacts of different types of capability on handoverdecision. If the capability of all 2G neighboring cells does not meet the requirement, theinter-RAT measurement will not be triggered.


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Table 2-4Impacts of different types of capability on handover decision

CellCapability

UE Capability Service Capability (Required by 2G)

EDGE GPRS GSM

EDGE EDGE Allowed Allowed Allowed

GPRS Allowed Allowed Allowed

GSM Not allowed Not allowed Allowed

Not supported by

2GNot allowed Not allowed Not allowed

GPRS EDGE Allowed Allowed Allowed

GPRS Allowed Allowed Allowed

GSM Not allowed Not allowed AllowedNot supported by


GSM EDGE Not allowed Not allowed Allowed

GPRS Not allowed Not allowed Allowed


Not supported by


Rules for Enabling Load- and Service-based 3G-to-2G Handover

The RNC initiates the load-based 3G-to-2G handover only when Service Handover Indicator

is set as follows:

HO_TO_GSM_SHOULD_BE_PERFORM


The RNC initiates the service-based 3G-to-2G handover only when the Service Handover

Indicator is set to HO_TO_GSM_SHOULD_BE_PERFORM.

The following three tables describe the impacts of different types of capability on handoverdecision.

Table 2-5Impacts of different types of capability on handover decision

CellCapability


EDGE GPRS GSM

EDGE EDGE Allowed Allowed Allowed

GPRS Not allowed Allowed Allowed



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CellCapability


EDGE GPRS GSM

Not supported by 2G Not allowed Not allowed Not allowed

GPRS EDGE Not allowed Allowed Allowed

GPRS Not allowed Allowed Allowed



GSM EDGE Not allowed Not allowed Allowed

GPRS Not allowed Not allowed Allowed



If the capability of all neighboring 2G cells does not meet the requirement, the inter-RATmeasurement will not be triggered.

Switches for Service-based 3G-to-2G Handover

To perform the service-based 3G-to-2G handover, the RNC must turn on the related switches

for services in the CS and PS domains.

When a single CS service is initially set up by the UE, the RNC allows the 3G-to-2Gservice-based handover ifCSServiceHOSwitch is set to ON.

When a single PS service is initially set up by the UE, the RNC allows the service-based3G-to-2G handover ifPSServiceHOSwitch is set to ON.

For the CS and PS combined services, no service-based handover is triggered.

Service Handover Indicator

The IE Service Handover Indicator indicates the CN policy for the service handover to the 2G

network. This IE is indicated in the Radio Access Bearer (RAB) assignment signalingassigned by the CN, or in Table 2-6 provided by the RNC side.

The algorithm switch HoSwitch: HO_INTER_RAT_RNC_SERVICE_HO_SWITCHdecides whether the service attribute of inter-RAT handover is based on the RNC or the CN.

If the switch is set to ON, the service attribute of inter-RAT handover is based on the

parameter configured on the RNC side.

If the switch is set to OFF, the service attribute of inter-RAT handover is first based on

the CN when the indicator is contained in the RAB assignment signaling assigned by theCN. If the CN does not allocate a service indicator, the service attribute of inter-RAT

handover is based on the RNC side.

Through the SHIND parameter, the service handover indicators are set as follows:

HO_TO_GSM_SHOULD_BE_PERFORM: means that the handover to the 2G network

is performed when 2G signals are available.


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HO_TO_GSM_SHOULD_NOT_BE_PERFORM: means that the handover to the 2Gnetwork is performed when 3G signals are weak but 2G signals are strong.

HO_TO_GSM_SHALL_NOT_BE_PERFORM: means that the handover to the 2Gnetwork is not performed even when 3G signals are weak but 2G signals are strong.

Figure 2-2 shows an example of rules for the indicator of the 3G-to-2G handover based onload and service.

Figure 2-2Example of rules for indicator of 3G-to-2G handover based on load and service

By default, the RNC does as follows:

For a UE with a single signaling RAB, the RNC supports the handover to the GSM. Butit is not recommended.

For the UE accessing combined services (with CS services), the RNC sets the service

handover indicator of the UE to that of the CS service, because the CS service has the

highest QoS priority.

For the UE accessing combined services (with only PS services), the RNC sets the

service handover indicator of the UE to that of the PS service, because the PS service hasthe highest QoS priority

If the service handover indicators are not configured by the CN, each indictor can be set to the

service parameter index of a service on the RNC. Eachservice parameter index is the index ofone typical service RAB, which involves a set of service type, source description, CN domain

ID, and maximum rate (bit/s).

Table 2-6 describes the service handover indicators recommended by Huawei.


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Table 2-6Service handover indicators (default values)

RAB

Index

Traffic

Direction

CNDomain

ID

Traffic

Class

MaxRate

(bit/s)

SourceDescripti

on

Service Handover

Indicator

Required2G

Capability

0Uplink and

downlink

CS_DOM

AIN

CONVER

SATION

AL12200 SPEECH

HO_TO_GSM_SHOUL

D_NOT_BE_PERFORMGSM

1Uplink anddownlink

CS_DOMAIN

CONVER

SATIONAL

23850 SPEECHHO_TO_GSM_SHOULD_NOT_BE_PERFORM

GSM

2Uplink and

downlink

CS_DOM

AIN

CONVERSATION

AL

28800UNKNO

WN

HO_TO_GSM_SHALL_

NOT_BE_PERFORMGSM

3

Uplink anddownlink

CS_DOM

AIN

CONVERSATION

AL32000

UNKNO

WN

HO_TO_GSM_SHALL_

NOT_BE_PERFORMGSM

4

Uplink and

downlinkCS_DOM

AIN

CONVER

SATIONAL

56000UNKNO

WN

HO_TO_GSM_SHALL_

NOT_BE_PERFORMGSM

5

Uplink anddownlink

CS_DOM

AIN

CONVERSATION

AL64000

UNKNO

WN

HO_TO_GSM_SHALL_

NOT_BE_PERFORMGSM

6Uplink and

downlink

CS_DOM

AIN

STREAM

ING57600

UNKNO

WN

HO_TO_GSM_SHALL_

NOT_BE_PERFORMGSM

11

Uplink and

downlinkPS_DOM

AIN

CONVER

SATION

AL8000

UNKNO

WN

HO_TO_GSM_SHALL_

NOT_BE_PERFORMGSM

12

Uplink anddownlink

PS_DOM

AIN

CONVERSATION

AL16000

UNKNO

WN

HO_TO_GSM_SHALL_

NOT_BE_PERFORMEDGE

13Uplink anddownlink

PS_DOM

AIN

CONVERSATION

AL

32000UNKNO

WN

HO_TO_GSM_SHALL_

NOT_BE_PERFORM

EDGE

15

Uplink and

downlinkPS_DOM

AIN

CONVER

SATIONAL

64000UNKNO

WN

HO_TO_GSM_SHALL_

NOT_BE_PERFORMEDGE

16

Uplink and

downlinkPS_DOMAIN

CONVER

SATION

AL38800

UNKNOWN

HO_TO_GSM_SHALL_NOT_BE_PERFORM

EDGE

17

Uplink and

downlinkPS_DOMAIN

CONVER

SATIONAL

39200UNKNOWN


EDGE


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2-11

RABIndex

TrafficDirection

CNDomainID

TrafficClass

MaxRate(bit/s)

SourceDescription

Service HandoverIndicator

Required2GCapab

ility

18

Uplink and

downlinkPS_DOMAIN

CONVER

SATION

AL40000

UNKNOWN


EDGE

19

Uplink and

downlinkPS_DOM

AIN

CONVER

SATIONAL

42800UNKNO

WN

HO_TO_GSM_SHALL_

NOT_BE_PERFORMEDGE

21Uplink and

downlink

PS_DOM

AIN

STREAM

ING8000

UNKNO

WN

HO_TO_GSM_SHALL_

NOT_BE_PERFORMEDGE

22Uplink and

downlink

PS_DOM

AIN

STREAM

ING 16000UNKNO

WN

HO_TO_GSM_SHALL_

NOT_BE_PERFORM EDGE

23Uplink and

downlink

PS_DOM

AIN

STREAM

ING32000

UNKNO

WN

HO_TO_GSM_SHALL_

NOT_BE_PERFORMEDGE

24Uplink and

downlink

PS_DOM

AIN

STREAM

ING64000

UNKNO

WN

HO_TO_GSM_SHALL_

NOT_BE_PERFORMEDGE

25Uplink and

downlink

PS_DOM

AIN

STREAM

ING128000

UNKNO

WN

HO_TO_GSM_SHALL_

NOT_BE_PERFORMEDGE

26Uplink and

downlink

PS_DOM

AIN

STREAM

ING144000

UNKNO

WN

HO_TO_GSM_SHALL_

NOT_BE_PERFORMEDGE

27Uplink and

downlink

PS_DOM

AIN

STREAM

ING256000

UNKNO

WN

HO_TO_GSM_SHALL_

NOT_BE_PERFORMEDGE

28Uplink and

downlink

PS_DOM

AIN

STREAM

ING384000

UNKNO

WN

HO_TO_GSM_SHALL_

NOT_BE_PERFORMEDGE

40Uplink and

downlink

PS_DOM

AIN

INTERAC

TIVE0

UNKNO

WN

HO_TO_GSM_SHOUL

D_NOT_BE_PERFORMGPRS

41Uplink and

downlink

PS_DOM

AIN

INTERAC

TIVE8000

UNKNO

WN

HO_TO_GSM_SHOUL


42

Uplink and

downlink

PS_DOM

AIN

INTERAC

TIVE 16000

UNKNO

WN

HO_TO_GSM_SHOUL

D_NOT_BE_PERFORM GPRS

43Uplink and

downlink

PS_DOM

AIN

INTERAC

TIVE32000

UNKNO

WN

HO_TO_GSM_SHOUL


44Uplink and

downlink

PS_DOM

AIN

INTERAC

TIVE64000

UNKNO

WN

HO_TO_GSM_SHOUL



PS_DOMAIN

INTERACTIVE

128000UNKNOWN


EDGE

46Uplink and

downlink

PS_DOM

AIN

INTERAC

TIVE144000

UNKNO

WN

HO_TO_GSM_SHOUL

D_NOT_BE_PERFORMEDGE


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02 (2009-06-30)

RABIndex

TrafficDirection

CNDomainID

TrafficClass

MaxRate(bit/s)

SourceDescription


Required2GCapab

ility

47Uplink and

downlink

PS_DOM

AIN

INTERAC

TIVE256000

UNKNO

WN

HO_TO_GSM_SHOUL


48Uplink and

downlink

PS_DOM

AIN

INTERAC

TIVE384000

UNKNO

WN

HO_TO_GSM_SHOUL


49 UplinkPS_DOM

AIN

INTERAC

TIVE608000

UNKNO

WN

HO_TO_GSM_SHALL_

NOT_BE_PERFORMEDGE

50 DownlinkPS_DOM

AIN

INTERAC

TIVE768000

UNKNO

WN

HO_TO_GSM_SHALL_

NOT_BE_PERFORMEDGE

51 Downlink PS_DOMAIN

INTERACTIVE

1024000 UNKNOWN


EDGE

52 UplinkPS_DOMAIN

INTERACTIVE

1440000UNKNOWN


EDGE

53 DownlinkPS_DOM

AIN

INTERAC

TIVE1536000

UNKNO

WN

HO_TO_GSM_SHALL_

NOT_BE_PERFORMEDGE

54 DownlinkPS_DOM

AIN

INTERAC

TIVE1800000

UNKNO

WN

HO_TO_GSM_SHALL_

NOT_BE_PERFORMEDGE

55Uplink and

downlink

PS_DOM

AIN

INTERAC

TIVE

2048000UNKNO

WN

HO_TO_GSM_SHALL_

NOT_BE_PERFORM

EDGE

56 UplinkPS_DOM

AIN

INTERAC

TIVE2880000

UNKNO

WN

HO_TO_GSM_SHALL_

NOT_BE_PERFORMEDGE

57 DownlinkPS_DOM

AIN

INTERAC

TIVE3600000

UNKNO

WN

HO_TO_GSM_SHALL_

NOT_BE_PERFORMEDGE

58 UplinkPS_DOMAIN

INTERACTIVE

5740000UNKNOWN


EDGE

59 DownlinkPS_DOM

AIN

INTERAC

TIVE7200000

UNKNO

WN

HO_TO_GSM_SHALL_

NOT_BE_PERFORMEDGE


INTERACTIVE

10100000 UNKNOWN


EDGE

61 DownlinkPS_DOM

AIN

INTERAC

TIVE13900000

UNKNO

WN

HO_TO_GSM_SHALL_

NOT_BE_PERFORMEDGE

62 DownlinkPS_DOM

AIN

INTERAC

TIVE21000000

UNKNO

WN

HO_TO_GSM_SHALL_

NOT_BE_PERFORMEDGE

63 DownlinkPS_DOM

AIN

INTERAC

TIVE27900000

UNKNO

WN

HO_TO_GSM_SHALL_

NOT_BE_PERFORMEDGE

70Uplink and

downlink

PS_DOM

AIN

BACKGR

OUND0

UNKNO

WN

HO_TO_GSM_SHOUL



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2-13

RABIndex

TrafficDirection

CNDomainID

TrafficClass

MaxRate(bit/s)

SourceDescription


Required2GCapab

ility

71Uplink and

downlink

PS_DOM

AIN

BACKGR

OUND8000

UNKNO

WN

HO_TO_GSM_SHOUL


72Uplink and

downlink

PS_DOM

AIN

BACKGR

OUND16000

UNKNO

WN

HO_TO_GSM_SHOUL


73Uplink and

downlink

PS_DOM

AIN

BACKGR

OUND32000

UNKNO

WN

HO_TO_GSM_SHOUL


74Uplink and

downlink

PS_DOM

AIN

BACKGR

OUND64000

UNKNO

WN

HO_TO_GSM_SHOUL


75 Uplink anddownlink

PS_DOMAIN

BACKGROUND

128000 UNKNOWN


EDGE


PS_DOMAIN

BACKGROUND

144000UNKNOWN


EDGE

77Uplink and

downlink

PS_DOM

AIN

BACKGR

OUND256000

UNKNO

WN

HO_TO_GSM_SHOUL


78Uplink and

downlink

PS_DOM

AIN

BACKGR

OUND384000

UNKNO

WN

HO_TO_GSM_SHOUL


79 UplinkPS_DOM

AIN

BACKGR

OUND

608000UNKNO

WN

HO_TO_GSM_SHALL_

NOT_BE_PERFORM

EDGE

80 DownlinkPS_DOM

AIN

BACKGR

OUND768000

UNKNO

WN

HO_TO_GSM_SHALL_

NOT_BE_PERFORMEDGE

81 DownlinkPS_DOM

AIN

BACKGR

OUND1024000

UNKNO

WN

HO_TO_GSM_SHALL_

NOT_BE_PERFORMEDGE

82 UplinkPS_DOMAIN

BACKGROUND

1440000UNKNOWN


EDGE

83 DownlinkPS_DOM

AIN

BACKGR

OUND1536000

UNKNO

WN

HO_TO_GSM_SHALL_

NOT_BE_PERFORMEDGE


BACKGROUND

1800000 UNKNOWN


EDGE

85Uplink and

downlink

PS_DOM

AIN

BACKGR

OUND2048000

UNKNO

WN

HO_TO_GSM_SHALL_

NOT_BE_PERFORMEDGE

86 UplinkPS_DOM

AIN

BACKGR

OUND2880000

UNKNO

WN

HO_TO_GSM_SHALL_

NOT_BE_PERFORMEDGE

87 DownlinkPS_DOM

AIN

BACKGR

OUND3600000

UNKNO

WN

HO_TO_GSM_SHALL_

NOT_BE_PERFORMEDGE

88 UplinkPS_DOM

AIN

BACKGR

OUND5740000

UNKNO

WN

HO_TO_GSM_SHALL_

NOT_BE_PERFORMEDGE


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02 (2009-06-30)

RABIndex

TrafficDirection

CNDomainID

TrafficClass

MaxRate(bit/s)

SourceDescription


Required2GCapab

ility

89 DownlinkPS_DOM

AIN

BACKGR

OUND7200000

UNKNO

WN

HO_TO_GSM_SHALL_

NOT_BE_PERFORMEDGE

90 DownlinkPS_DOM

AIN

BACKGR

OUND10100000

UNKNO

WN

HO_TO_GSM_SHALL_

NOT_BE_PERFORMEDGE

91 DownlinkPS_DOM

AIN

BACKGR

OUND13900000

UNKNO

WN

HO_TO_GSM_SHALL_

NOT_BE_PERFORMEDGE

92 DownlinkPS_DOM

AIN

BACKGR

OUND21000000

UNKNO

WN

HO_TO_GSM_SHALL_

NOT_BE_PERFORMEDGE


BACKGROUND

27900000 UNKNOWN


EDGE

Note:

Rows without RAB index are all NA.


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Handover 3 Intra-Frequency Handover Algorithms



3-1

3 Intra-Frequency Handover Algorithms3.1 Intra-Frequency Handover Procedure

The intra-frequency handover procedure is divided into three phases: handover measurement,handover decision, and handover execution.

After the UE transits to the CELL_DCH state in connected mode during a call, the RNCsends a MEASUREMENT CONTROL message to instruct the UE to take measurements and

report the measurement event results.

The MEASUREMENT CONTROL message carries the following information:

Event trigger threshold

Hysteresis value

Event trigger delay time

Neighboring cell list

Upon the reception of an event report from the UE, the RNC makes a handover decision andperforms the corresponding handover, as shown in Figure 3-1.

Figure 3-1Intra-frequency handover procedure

3.2 Intra-Frequency Handover MeasurementIn the measurement phase, the UE takes measurements according to the MEASUREMENTCONTROL message received from the RNC. When the event triggering conditions are met,

the UE sends measurement reports to the RNC according to the rules defined in the

MEASUREMENT CONTROL message.


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3 Intra-Frequency Handover Algorithms

RAN

Handover



02 (2009-06-30)

3.2.1 Intra-Frequency Handover Measurement Quantities

Intra-frequency handover uses Ec/No or RSCP of the CPICH as the measurement value.

Intra-frequency handover measurement events can be configured through the parameterIntraFreqMeasQuantity.

The UE performs layer 3 filtering on measurement values before it decides measurementevents and sends measurement reports. The measurement model, as shown in Figure 3-2, isdefined in 3GPP25.302. Figure 3-2 shows the position of layer 3 filtering in the measurement

procedure.

Figure 3-2Measurement model in the WCDMA system

Figure 3-2 also shows the measurement points of the model, where

A: measurement value of the physical layer

B: measurement value obtained after layer-1 filtering. The value is weighted by the layer

3 filtering coefficient.

C: measurement value obtained after layer 3 filtering. This value is controlled by the

higher layer. Filtering coefficient C is applicable to event reports and periodic reports. C': another measurement value. C' and C are measured in the same way.

D: measurement report information (message) of Uu or Iub transmission.

Parameters (a) include the layer 3 filtering system and Parameters (b) include the

measurement report configuration.

The calculation is based on the following formula:

Fn = (1 - ) x Fn-1+ x Mn

Fn: measurement value obtained after the nth filtering

Fn-1: measurement value obtained after the (n-1)th filtering

Mn: measurement value of the nth physical layer

= 1/2(k/2)

: k is determined by the parameter which is the layer 3 filtering coefficient ofintra-frequency handover measurement.

When is set to 1, k = 0 and layer3 filtering is not performed.

3.2.2 Intra-Frequency Handover Measurement Events

In intra-frequency handover, the UE reports measurement results to the RNC through event

reporting.


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3-3

Event Description

1A A primary CPICH enters the reporting range. This indicates that the quality of a

cell is close to the quality of the best cell in the active set. A relatively high

combined gain can be achieved when the cell is added to the active set.

1B A primary CPICH leaves the reporting range. This indicates that a cell has a lower

quality than the best cell in the active set. The cell has to be deleted from the

active set.

1C A non-active primary CPICH becomes better than an active primary CPICH. This

indicates that the quality of a cell is better than the quality of the worst cell in the

active set. The RNC replaces a cell in the active set with a cell in the monitoredset.

1D The best cell changes.

1J RAN10.0 provides the solution to the issue of how to add an HSUPA cell in a

DCH active set to an E-DCH active set. Event 1J is added to the 3GPP protocol.This event is triggered when a non-active E-DCH but active DCH primary

CPICH becomes better than an active E-DCH primary CPICH.

Triggering of Event 1A

Event 1A is triggered under the following condition:

10 x Log(MNew)+ CIONew W x 10 x Log(

AN

i

iM

1

) + (1 - W) x 10 x Log(MBest) - (R1a -

H1a/2)

MNew is the measurement value of the cell in the reporting range.

CIONew is equal to the sum ofCIO and CIOOffset, which adjusts the cell boundary in

the handover algorithms. This parameter is determined by network planning according toactual environment configuration. To facilitate handover in neighboring cell

configuration, the parameter is set as a positive value; otherwise, the parameter is set as anegative value.

W represents Weighted factor, which is determined by the parameter Weight. The total

quality of the best cell and the active set is specified by W.

Mi is the measurement value of a cell in the active set.

NA is the number of cells not forbidden to affect the reporting range in the active set. Theparameter CellsForbidden1A indicates whether adding the cell to the active set affectsthe relative threshold of event 1A.

MBest is the measurement value of the best cell in the active set.

R1a is the reporting range or the relative threshold of soft handover. The threshold

parameters of the CS non-VP service, VP service, and PS service are as follows:

IntraRelThdFor1ACSVP

IntraRelThdFor1ACSNVP

IntraRelThdFor1APS


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For the PS and CS combined services, the threshold for CS services is used.

For the single signaling connection of the UE, the threshold for CS services is used.

H1a represents 1A hysteresis, the hysteresis value of event 1A

Figure 3-3 shows the triggering of event 1A. In this procedure, the default parameter valuesare used.

If the signal quality of a cell that is not in the active set is higher than Th1A for a period oftime specified by TrigTime1A (that is, Time to trigger in Figure 3-3), the UE reports event

1A.

Th1A = (CPICH Ec/No of the best cell in the active set) - (reporting range for event 1A)

IfWeighted factor > 0, then Th1A = (general signal quality of all the cells in the activeset) - (reporting range for event 1A).

Reporting range for event 1A is equal to the value ofIntraRelThdFor1ACSVP,

IntraRelThdFor1ACSNVP, or IntraRelThdFor1APS.

Figure 3-3Triggering of event 1A

A: signal quality curve of the best cell in the active set

B: signal quality curve of a cell in the monitored set

C: curve of Th1A

Triggering of Event 1B

Event 1B is triggered under the following condition:

10 x Log(Mold)+ CIOold W x 10 x Log(

BN

i

iM

1

) + (1-W) x 10 x Log(MBest) - (R1b+H1b/2)

MOld is the measurement value of the cell that becomes worse.

CIOOld is equal to the sum ofCIO and CIOOffset, which is the offset between the cell inthe reporting range and the best cell in the active set.


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3-5

W represents Weighted factor, used to weight the quality of the active set. The totalquality of the best cell and the active set is specified by the parameter Weight.

Mi is the measurement value of a cell in the active set.

NB is the number of cells not forbidden to affect the reporting range in the active set. The

parameter CellsForbidden1B indicates whether adding the cell to the active set affectsthe relative threshold of event 1B.


R1b is the reporting range or the relative threshold of soft handover. The threshold

parameters of the CS non-VP service, VP service, and PS services are as follows:

IntraRelThdFor1BCSVP

IntraRelThdFor1BCSNVP

IntraRelThdFor1BPS

For the PS and CS combined services, the threshold for CS services is used.

If the UE currently has only signaling connections, the threshold for CS services is used. H1b is the hysteresis value of event 1B, which is determined by the parameter

Hystfor1B.

Configuration rule and restriction

The value ofIntraRelThdFor1BCSNVP has to be larger than that ofIntraRelThdFor1ACSNVP.

The value ofIntraRelThdFor1BCSVP has to be larger than that ofIntraRelThdFor1ACSVP.

The value ofIntraRelThdFor1BPS has to be larger than that ofIntraRelThdFor1APS.

Figure 3-4 shows the triggering of event 1B. In this procedure, the default parameter values

are used.

Figure 3-4Triggering of event 1B


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B: signal quality curve of the best cell in the monitored set

C: curve of Th1B

Th1B = (CPICH Ec/No of the best cell in the active set) - (reporting range for event 1B)where

Reporting range for event 1B is equal to the value ofIntraRelThdFor1BCSVP,IntraRelThdFor1BCSNVP, or IntraRelThdFor1BPS.

IfWeight > 0, then Th1B = (general signal quality of all the cells in the active set) -(reporting range for event 1B).

If the signal quality of a cell in the active set is lower than Th1B for a period of time specified

by TrigTime1B (Time to trigger in the figure), the UE reports event 1B.

Triggering of Event 1C

Event 1C is triggered under the following condition:

10 x Log(MNew)+ CIONew 10 x Log(MInAS) + CIOInAS + H1c/2

MNew is the measurement value of the cell in the reporting range.

CIONew is the cell individual offset value of the cell in the reporting range. It is equal tothe sum ofCIO and CIOOffset, which is the offset between the cell in the reportingrange and the best cell in the active set.

MInAS is the measurement value of the worst cell in the active set.

H1c is the hysteresis value of event 1C, which is determined by the parameterHystfor1C.

Figure 3-5 shows the triggering of event 1C. In this procedure, the default parameter values

are used.

Figure 3-5Triggering of event 1C


B: signal quality curve of a cell in the active set


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3-7

C: signal quality curve of the worst cell in the active set

D: signal quality curve of a cell in the monitored set

E: curve of Th1C

Th1C = (CPICH Ec/No of the worst cell in the active set) + (hysteresis/2)where

Hysteresis is equal to the value ofHystfor1C.

If the signal quality of a cell not in the active set is higher than Th1C for a period of time

specified by TrigTime1C (Time to trigger in the figure), the UE reports event 1C, as shownin the figure.

The UE reports event 1C for qualified cells after the number of cells in the active set reaches

the maximum value. The maximum number of cells in the active set can be set by the

MaxCellInActiveSet parameter.

Triggering of Event 1D

Event 1D is triggered under the following condition:

10 x Log(MNotBest)+ CIONotBest 10 x Log(MBest) + CIOBest + H1d/2

MNotBest is the measurement value of a cell that is not the best cell.

CIONotBest is equal to the sum ofCIO and CIOOffset, which is the offset between thecell in the reporting range and the best cell in the active set.


CIOBest is the cell individual offset value of the best cell. This parameter is not used for

event 1D.

H1d is the hysteresis value of event 1D, which is determined by the parameterHystfor1D.

Figure 3-6 shows the triggering of event 1D. In this procedure, the default parameter valuesare used.

Figure 3-6Triggering of event 1D


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B: signal quality curve of a cell in the active set or the monitored set

C: curve of Th1D

Hysteresis is equal to the value ofHystfor1D.

If the signal quality of a cell not in the active set is higher than Th1D for a period of timespecified by TrigTime1D (Time to trigger in the figure), the UE reports event 1D.

Triggering of Event 1J

Event 1J is triggered under the following condition:

10 x Log(MNew)+ CIONew 10 x Log(MInAS) + CIOInAS + H1j/2

MNew is the measurement result of the cell not in the E-DCH active set but in the DCHactive set.

CIONew

and CIOInAS

refer to the offset of each cell.

MInAS is the measurement result of the cell in the E-DCH active set with the lowest

measurement result.

H1J is the hysteresis parameter for event 1J and is determined by Hystfor1J.

If the measurement result is CPICH-Ec/No, MNew and MInAS are expressed as ratios.

If the measurement result is CPICH-RSCP, MNew and MInAS are expressed in mW.

Figure 3-7Triggering of event 1J

A: signal quality curve of a cell in the E-DCH active set

B: signal quality curve of the worst cell in the E-DCH active set

C: signal quality curve of a cell not in the E-DCH active set but included in DCH active

set

D: signal quality curve of a cell not in the E-DCH active set but included in DCH active

set

In Figure 3-7, the hysteresis and the cell individual offsets for all cells equal 0.


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3-9

The first measurement report is sent when primary CPICH D becomes better than primaryCPICH B. The "cell measurement event result" of the measurement report contains the

information of primary CPICH D and CPICH B.

On the assumption that the E-DCH active set has been updated after the first measurement

report (E-DCH active set is now primary CPICH A and primary CPICH D), the second reportis sent when primary CPICH C becomes better than primary CPICH A. The "cell

measurement event result" of the second measurement report shows that primary CPICH C is

better than primary CPICH A in quality.

The following parameters need to be set on the RNC LMT:

Hystfor1J: hysteresis of event 1F

TrigTime1J: time to trigger event 1J

PeriodMRReportNumfor1J: number of periodic reports for event 1J

ReportIntervalfor1J: report interval for event 1J after change to the periodic report

HO_INTRA_FREQ_RPRT_1J_SWITCH: measurement control switch for event 1J.When the switch is ON, the UE version is R6 and event 1J is included in theintra-frequency measurement control message.

After receiving the intra-frequency measurement report from the UE, the RNC decides

whether to go to the execution phase, depending on the information in the report.

3.2.3 Intra-Frequency Handover Neighboring Cell CombinationAlgorithm

After the active set is updated, the RNC updates the neighboring cell list by using the

neighboring cell combination algorithm according to the status of the active set. This list

includes the new intra-frequency, inter-frequency, and inter-RAT neighboring cells. Thecombination methods of intra-frequency handover, inter-frequency handover, and inter-RAT

handover are the same.

If the radio link of the Drift RNC (DRNC) is added to the active set, the Source RNC (SRNC)buffers the intra-frequency, inter-frequency, and inter-RAT neighboring cell lists of the DRNCuntil the radio link of the DRNC is released.

The neighboring cell combination result is contained in the MEASUREMENT CONTROLmessage and sent to the UE, which instructs the UE to perform intra-frequency,

inter-frequency, and inter-RAT measurement and handover procedures.

The number of inter-frequency neighboring cells is configured as follows:

A maximum of 32 intra-frequency neighboring cells are configured. A maximum of 32 single-carrier inter-frequency neighboring cells are configured.

A maximum of 64 multi-carrier inter-frequency neighboring cells are configured.

A maximum of 32 inter-RAT neighboring cells are configured.

Neighboring Cell Combination Switch

HO_MC_NCELL_COMBINE_SWITCH is the neighboring cell combination switch.

If the switch is set to ON, measurement objects are chosen from the neighboring cells of

all the cells in the active set.


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02 (2009-06-30)

If the switch is set to OFF, measurement objects are chosen from the neighboring cellsof the best cell.

HO_MC_NCELL_COMBINE_SWITCH is set to ON by default.

Description of the Neighboring Cell Combination Algorithm

After obtaining the intra-frequency neighboring cells of each cell in the active set, the RNC

calculates the union neighboring cell set of the intra-frequency cells, which is referred as Sall,

by using the following method. This method can also be used to generate the Sall ofinter-frequency or inter-RAT cells.

The intra-frequency, inter-frequency, and inter-RAT neighboring cells of each cell in thecurrent active set are obtained.

The RNC sequences the cells in the active set in descending order of CPICH Ec/No

according to the latest measurement report (event 1A, 1B, 1C, or 1D) from the UE. Thebest cell is based on event 1D, whereas other cells are based on the latest measurement

report. The cells in the active set are added to Sall.

The neighboring cells of the best cell in the active set are added to Sall. NprioFlag (theflag of the priority) and Nprio (the priority of the neighboring cell), which are set foreach neighboring cell, are used to change the order of adding the neighboring cells to

Sall.

When NprioFlag is switched to FALSE, NPrio is cleared.

When NprioFlag is switched to TRUE, NPrio is set simultaneously.

The neighboring cells of other cells in the active set are added to Sall in descending orderby CPICH Ec/No values of these cells in the active set. The neighboring cells of thesame cell in the active set are added according to Nprio and the number of repeated

neighboring cell is recorded.

If there are more than 32 intra-frequency neighboring cells in Sall, delete the repeated

neighboring cells whose number in Sall is less. The top 32 neighboring cells are grouped into

the final Sall.

If there are more than 64 (multi-carrier) or 32 (single-carrier) inter-frequency neighboring

cells in Sall, the top 64 or 32 neighboring cells are grouped into the final Sall.

3.3 Intra-Frequency Handover Decision and Execution

The intra-frequency handover decision and execution procedure depends on the differentmeasurement events that the RNC receives.

3.3.1 Decision and Execution

Table 3-1 lists different types of intra-frequency handover decision and execution based on

different events.


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Table 3-1Intra-frequency handover decision and execution

Event Decision and Execution

1A When receiving an event 1A report, the RNC decides whether to add a cell.

For event 1A, the UE can report more than one cell in the event list in onemeasurement report. These cells are in the list of the MEASUREMENTCONTROL message, and they are sequenced in descending order ofmeasurement quantity.

For the cells in the list, the RNC adds the radio link to the active set only if the

number of cells in the active set does not reach the maximum value. This

operation is not required if the number of cells in the active set reaches aspecified value.

1B When receiving an event 1B report, the RNC decides whether to delete a cell.

For event 1B, if there is more than one radio link in the active set, the RNCdecides whether to delete a radio link. This operation is not required if there is

only one radio link in the active set.

1C When receiving an event 1C report, the RNC decides whether to change the

worst cell.

For event 1C, the UE reports a list that contains good cells and the cells to be

replaced, and sequences the cells in descending order by measurement quantity.After receiving the list from the UE, the RNC replaces the bad cells in the active

set with the good cells in the list.

1D As stipulated in related protocols, an event 1D report includes information about

only one cell. This cell can be listed in an active set or a monitored set. The RNClearns that the quality of this cell is better than that of the serving cell and takes

one of the following actions:If the reported cell is in the active set, the RNC decides whether to change the

best cell or reconfigure measurement control.

If the reported cell is in the monitored set, then:

If the number of cells in the active set has not reached the maximum value, theRNC adds the cell to the active set.

If the number of cells in the active set has reached the maximum value, the

RNC replaces the worst cell in the active set with the reported cell.

The best cell is changed to the reported cell.

The RNC determines whether the intra-frequency hard handover scenarios areapplicable. For detailed information, see 2.1 Handover Types. If any scenario is

applicable, the RNC performs an intra-frequency hard handover.

1J When receiving an event 1J report with information about the good cells and the

cells to be replaced, the RNC proceeds as follows:

If the current number of cells in the E-DCH active set is smaller than the value

ofMaxEdchCellInActiveSet, the uplink of the cell where event 1J is triggeredis reconfigured to E-DCH.

If the current number of cells in the E-DCH active set is equal to the value of

MaxEdchCellInActiveSet, the RNC searches the measurement report for the

non-serving E-DCH with the lowest measured quality in the E-DCH active set.

Then, the uplink of the cell where event 1J is triggered is reconfigured from

DCH to E-DCH.


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Minimum Quality Threshold for Soft Handover

When receiving an event 1A, 1C, or 1D report, the RNC adds a target cell to the active setonly when the CPICH Ec/No of the target cell is higher than the absolute threshold

SHOQualmin.

SHO: soft handover

Switch for Cross-Iur Intra-Frequency Handover

If the RRC connection has been set up but the Radio Bearers (RBs) have not, whether a

cross-Iur soft handover can be executed is determined by

HO_MC_SIGNAL_IUR_INTRA_SWITCH of the SET CORRMALGOSWITCHparameter. Only if the switch is set to ON, can the cross-Iur soft handover be executed.

3.3.2 Rate Reduction After an SHO Failure

If the radio link addition for a soft handover fails, the rate reduction is triggered for R99 NRT(Non Real Time) services to increase the probability of a successful soft handover.

Estimation Procedure for Rate Reduction

If the RNC receives a 1A, 1C, or 1D measurement report, the RNC tries to add the

corresponding cell to the active set. If the addition fails, the RNC performs the estimationprocedure for rate reduction.


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Figure 3-8Estimation procedure for rate reduction

1. The RNC evaluates whether the measurement quantity of the cell failing to be admittedmeets the condition of rate reduction.

If the condition is met, the RNC performs a rate reduction process for the accessservice immediately, as described in the next section Procedure of Rate ReductionExecution.

If the condition is not met, the RNC performs the next step (Step 2).

The condition of rate reduction is as follows: Mnew > Mbest_cell - RelThdForDwnGrd

Mnew is the CPICH Ec/No measurement value of the cell failing to be admitted.

Mbest_cell is the CPICH Ec/No measurement value of the best cell in the active set.

RelThdForDwnGrd is configured through the parameter Relative threshold of SHO

failure.

2. The RNC evaluates whether the number of SHO failures in the cell exceeds theThreshold number of SHO failure.

If the number of SHO failures in the cell is smaller than the ShoFailNumForDwnGrd:

If the timer has not been started, the RNC starts it.

If the timer has been started, the RNC increments the SHO failure counter by one.

The timer length is set through the parameter ShoFailPeriod.

The SHO failure counter of a cell is used to record the number of SHO failures in this

cell. For each UE, the RNC records the number of SHO failures in three cells at most.For SHO failures in any other cells, the RNC does not record the number.

Before the SHO failure evaluation timer expires, no action is taken and the RNC waits

for the next measurement report period.

When the SHO failure evaluation timer expires, the RNC sets the SHO failure counter ofthe corresponding cell to 0 and ends the evaluation.


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If the number of SHO failures in the cell is larger than or equal to the parameterShoFailNumForDwnGrd, the RNC performs a rate reduction process for the access

service,

Procedure of Rate Reduction Execution

Figure 3-9Procedure of rate reduction execution

2. The RNC performs a rate reduction process for the access service. The method ofdetermining the access rate after the rate reduction is the same as that described in RateNegotiation ofLoad Control Parameter Description.

3. After the rate reduction succeeds, the RNC immediately attempts to add this cell to theactive set without measurement:

If the cell succeeds in admitting the UE, the RNC adds the radio link and sets the SHO

failure counter of the cell to 0 and ends the execution. If the cell fails to admit the UE, the RNC starts the Period of penalty timer for SHO

failure after down rate to avoid an increase in the rate triggered by DCCC within theperiod. Also in this period, the RNC sets the SHO failure counter of the cell to 0 and

ends the execution.

If the RNC fails to perform a soft handover again, it performs the estimation procedure and

the execution procedure, as previously described.


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3.4 Intra-Frequency Handover of HSDPAThis section describes the decision and execution of intra-frequency handover, and the

handover between a cell supporting the F-DPCH and a cell not supporting the F-DPCH after

the introduction of HSDPA.

3.4.1 Decision and Execution of Intra-Frequency Handover

Handling of Event 1A

After receiving an event 1A report, the RNC proceeds as follows:

If the number of cells in the active set does not reach the maximum value, the RNC addsthe cell to the active set.

If the number of cells in the active set reaches the maximum value, the RNC does not

add the radio link to the active set.

Handling of Event 1B

After receiving an event 1B report, the RNC determines whether to delete a cell.

If the cell to be deleted is not an HSDPA serving cell, the cell is directly removed.

If the cell to be deleted is an HSDPA serving cell, then:

If the new best cell supports HSDPA, the new best cell is reconfigured to be an

HSDPA serving cell. If the reconfiguration fails, the service is reconfigured ontoDPCH.

If the new best cell does not support HSDPA, the service is reconfigured onto DPCH

to ensure the continuity of the service.

Handling of Event 1C

After receiving an event 1C report, the RNC decides whether to change the worst cell.

If the cell to be replaced is not an HSDPA serving cell, the cell is directly removed.

If the cell to be replaced is an HSDPA serving cell, then:

If the best cell supports HSDPA, the best cell is reconfigured to be an HSDPA servingcell. If the reconfiguration fails, the service is reconfigured onto DPCH.

If the best cell does not support HSDPA, the service is reconfigured onto DPCH to

ensure the continuity of the service.

Handling of Event 1D

After receiving an event 1D report, the RNC proceeds as follows:

If the downlink service is carried on the HSDPA, then:

If the new best cell in the active set supports HSDPA and the HSPA hysteresis timerexpires, the new best cell is reconfigured to be an HSDPA serving cell. The HSPAhysteresis timer is restarted after the serving cell change and is to avoid frequent

updates at the boundary between two HSDPA cells. The timer length is specified by

the parameter HspaTimerLen.

Figure 3-10 shows an example of how to handle event 1D in this situation. Assumethat the UE moves from HSDPA cell 1 to HSDPA cell 2, that the two cells are


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intra-frequency neighboring cells, and that all the cells in the active set supportHSDPA. The RNC updates the HSDPA serving cell according to the reported event

and keeps the HSDPA serving cell consistent with the best cell.

If the new best cell in the active set does not support HSDPA, the downlink service is

directed to the DCH through the reconfiguration.

Figure 3-10Intra-frequency handover between HSDPA cells when the best cell changes

If the downlink service is carried on the DCH, then:

To avoid frequent handovers at the boundary between an HSDPA cell and an R99 cell, aprotection timer is used. After an intra-frequency handover, the timer starts. After this

timer expires, the RNC reconfigures the service of the UE onto the HS-PDSCH of the

HSDPA cell if either of the following two conditions is met:

The target cell supports HSDPA.

The target cell does not support HSDPA but has a DRD neighboring cell.

The timer length is specified by the parameter ChannelRetryHoTimerLen.

In the execution procedure mentioned above,CMP_UU_SERV_CELL_CHG_WITH_ASU_SWITCHof the CmpSwitch parameter is

used to determine whether the update of the active set and the change of the serving cell aresynchronized. This switch is applicable to only R6 UEs.

If the switch is ON, the UE supports the synchronization of the update of the active setand the change of the serving cell.

If the switch is OFF, the UE reconfigures the change of the serving cell by allocating

physical channels after updating the active set.

During the update of the HSDPA serving cell, set the NBMMachsResetAlgoSelSwitchparameter to determine whether to reset the UE MAC-hs.

3.4.2 F-DPCH Handover Protection

If all the cells in the active set support the F-DPCH after the active set is updated and the

Signaling Radio Bearer (SRB) is carried on the DCH, the timer ChannelRetryHoTimerLenstarts. After this timer expires, the RNC decides whether to switch the SRB to the HS-DSCH.


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After the UE is handed over to an HSDPA cell from an R99 cell, the D2HRetryTimer starts.After this timer expires, the RNC decides whether to switch the SRB to the HS-DSCH and

whether to set up the F-DPCH.D2HRetryTimer is set through ChannelRetryHoTimerLen.

3.5 Intra-Frequency Handover of HSUPAThis section describes the decision and execution of intra-frequency handover, and the

handover between E-DCHs of 10 ms TTI and 2 ms TTI after the introduction of HSUPA.

3.5.1 Decision and Execution of Intra-Frequency Handover

Handling of Event 1A

After receiving the measurement report, the RNC proceeds as follows:

If the target cell supports HSUPA and the uplink service is carried on the E-DCH, then:

If the current number of cells in the E-DCH active set is smaller than the value of

MaxEdchCellInActiveSet, the target cell is added to both the DCH and E-DCH activesets.

Otherwise, the target cell is added to only the DCH active set.

After deciding that a cell can be added to the E-DCH active set,

If the admission in the downlink fails, the cell is added to neither the E-DCH active set

nor the DCH active set. It waits for the next event 1A report for retry.

Otherwise, if the admission in the downlink succeeds, the RNC perform the HSUPAadmission in the uplink.

If HSUPA admission in the uplink succeeds, the cell is added to the E-DCH active set

and the DCH active set.

If HSUPA admission in the uplink fails, the cell is added only to the DCH active set.If the DCH admission in the uplink still fails, the cell is added to neither the E-DCHactive set nor the DCH active set. It waits for the next event 1A report for retry.

Handling of Event 1B

If the number of radio links in the DCH active set is larger than one, then:

If the cell to be removed is not an HSUPA serving cell, the cell is directly removed.

If the cell to be removed is an HSUPA serving cell, then: