OWO113030 WCDMA RAN11 Handover Algorithm and Parameters ISSUE1.02

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

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WCDMA Handover Algorithm and

Parameters

Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved. Page3

Foreword

Why mobile system need handover?

The mobility of UE

Load Balance

Any others?


References 3GPP TS 23.122: Non Access Stratum functions related to

Mobile Station (MS) in idle mode

3GPP TS 24.008: Mobile radio interface layer 3 specification; Core Network Protocols - Stage 3

3GPP TS 25.304: UE Procedures in Idle Mode and Procedures for Cell Reselection in Connected Mode

3GPP TS 25.331: RRC Protocol Specification

3GPP TS 23.060: General Packet Radio Service (GPRS); Service description

3GPP TS 25.931: UTRAN Functions, Examples on Signalling Procedures


Objectives

Upon completion of this course, you will be able to:

Explain the features of each handover

Describe the procedures of each handover

Perform the parameters setting of each handover


The Basic Concepts of Handover Active set

Monitored set

Detected set

Radio link (RL)

Radio link set (RLS)

Maximum ratio

combination

Selective combination

Soft handover gain

PCPICH


Contents

1. Intra-Frequency Handover

2. Inter-Frequency Handover

3. Inter-RAT Handover


Contents





Contents


1. Intra-Frequency Handover Overview

2. Intra-Frequency Handover Procedure

3. Signaling Procedures for Intra-Frequency Handover


Intra-Frequency Handover Types The carrier frequencies of the current cell and target cell

are the same:

Intra-frequency soft handover

Intra-frequency hard handover


Intra-Frequency Handover Types (Cont.)

Item Soft Handover Hard Handover

The number of RLs in

active set during

handover

Several One

Interruption during

handoverNo Yes

The frequencies of

cells

Only happened

between Intra-

frequency cells

Can be happened in Intra-

frequency cells or Inter-

frequency cells

Comparison between soft handover and hard

handover:


Intra-Frequency Soft 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 (cont.)

Item Softer Handover Soft Handover

Scenario

When the UE is in the

overlapped coverage area of

two neighboring cells of a

NodeB with combined RLs

When the UE is in the

overlapped coverage area of

two neighboring cells of

different NodeBs

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

Comparison between soft handover and softer

handover:


Intra-Frequency Hard Handover Intra-frequency hard handover:

No Iur interface

Iur interface is congested

High-speed Best Effort (BE) service Handover

Soft handover fails


Contents






Intra-Frequency Handover Procedure

Decision

Execution

Measurement


Contents




1. Intra-Frequency Handover Measurement

2. Intra-Frequency Handover Decision and Execution

3. Neighboring Cell Combination Algorithm



Intra-Frequency Handover Measurement Measurement control:

UE UTRAN

MEASUREMENT CONTROL


Intra-Frequency Handover Measurement (Cont.) Measurement report:

UE UTRAN

MEASUREMENT REPORT


Intra-Frequency Handover Measurement (Cont.)

nnn MFF 1)1(

Measurement model in the WCDMA system:

L3 filtering formula:


Parameters of Intra-Frequency Measurement IntraFreqMeasQuantity

Parameter name: Intra-freq Measure Quantity

Recommended value: CPICH_EC/NO

FilterCoef

Parameter name: Intra-freq meas L3 filter coeff

Recommended value: D3, namely K=3


Intra-Frequency Handover Measurement EventsEven

tDescription

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.

1BA 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 monitored set.

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.


Intra-Frequency Handover Measurement Events (Cont.)

)2/()1()( 111

aaBest

N

iiNewNew HRMWMWCIOM

A

1A event

Event 1A is triggered on the basis of the following

formula:



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


Parameters of Intra-Frequency Handover (Cont.) CIO

Parameter name: Cell oriented Cell Individual Offset

Recommended value: 0, namely 0dB

CIOOffset

Parameter name: Neighboring cell oriented CIO



Parameters of Intra-Frequency Handover (Cont.) IntraRelThdFor1ACSNVP

Parameter name: CS non VP service 1A event relative THD


IntraRelThdFor1ACSVP

Parameter name: VP service 1A event relative THD


IntraRelThdFor1APS

Parameter name: PS service 1A event relative threshold



Parameters of Intra-Frequency Handover (Cont.) Hystfor1A

Parameter name: 1A hysteresis


TrigTime1A

Parameter name: 1A event trigger delay time

Recommended value: D320, namely 320ms

Weight

Parameter name: Weighted factor

Recommended value: 0


Intra-Frequency Handover Measurement Events (Cont.) 1A event report mode:

Event trigger report

Event to periodical report


Parameters of Intra-Frequency Handover (Cont.) ReportIntervalfor1A

Parameter name: 1A event to periodical rpt period


PeriodMRReportNumfor1A

Parameter name: 1A event to periodical rpt number

Recommended value: D16



)2/()1()( 111

bbBest

N

iiOldOld HRMWMWCIOM

A

1B event

Event 1B is triggered on the basis of the following

formula:




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

C: curve of Th1B


Parameters of Intra-Frequency Handover (Cont.) IntraRelThdFor1BCSNVP

Parameter name: CS non VP service 1B event relative

THD


IntraRelThdFor1BCSVP

Parameter name: VP service 1B event relative THD


IntraRelThdFor1BPS

Parameter name: PS service 1B event relative threshold



Parameters of Intra-Frequency Handover (Cont.) Hystfor1B

Parameter name: 1B hysteresis


TrigTime1B

Parameter name: 1B event trigger delay time




2/1cInASInASNewNew HCIOMCIOM

1C event

Event 1C is triggered on the basis of the following

formula:




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

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


Parameters of Intra-Frequency Handover (Cont.) Hystfor1C

Parameter name: 1C hysteresis


TrigTime1C

Parameter name: 1C event trigger delay time



Intra-Frequency Handover Measurement Events (Cont.) 1C event report mode:




Parameters of Intra-Frequency Handover (Cont.) ReportIntervalfor1C

Parameter name: 1C event to periodical rpt period


PeriodMRReportNumfor1C

Parameter name: 1C event to periodical rpt number




2/1dBestBestNotBestNotBest HCIOMCIOM

1D event

Event 1D is triggered on the basis of the following

formula:




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

C: curve of Th1D


Parameters of Intra-Frequency Handover (Cont.) Hystfor1D

Parameter name: 1D hysteresis


TrigTime1D

Parameter name: 1D event trigger delay time




2/1JInASInASNewNew HCIOMCIOM

1J event

Event 1J is triggered on the basis of the following

formula:



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


Parameters of Intra-Frequency Handover (Cont.) Hystfor1J

Parameter name: 1J hysteresis


TrigTime1J

Parameter name: 1J event trigger delay time


MaxEdchCellInActiveSet

Parameter name: Max number of cell in EDCH active set



Intra-Frequency Handover Measurement Events (Cont.) 1J event report mode:




Parameters of Intra-Frequency Handover (Cont.) ReportIntervalfor1J

Parameter name: 1J event to periodical rpt period


PeriodMRReportNumfor1J

Parameter name: 1J event to periodical rpt number



Contents









Intra-Frequency Handover Decision and Execution The intra-frequency handover decision and

execution procedure depends on the different

measurement events that the RNC receives:

1A Event

1B Event

1C Event

1D Event

1J Event


Parameters of Intra-Frequency Handover (Cont.) MaxCellInActiveSet

Parameter name: Max number of cell in active set


SHOQualmin

Parameter name: Min quality THD for SHO

Recommended value: -24, namely -24dB


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

handover1A,1C,1D is received by RNC

Execute admission control in target cell

Admission succeed?

Execute Handover

Rate Reduction

Estimation

Execution

Yes

No


Estimation Procedure for Rate Reduction


Parameters of Intra-Frequency Handover (Cont.) RelThdForDwnGrd

Parameter name: Relative threshold of SHO failure


ShoFailPeriod

Parameter name: Max evaluation period of SHO failure

Recommended value: 60, namely 60s

ShoFailNumForDwnGrd

Parameter name: Threshold number of SHO failure



Procedure of Rate Reduction Execution


Parameters of Intra-Frequency Handover (Cont.) DcccShoPenaltyTime

Parameter name: Period of penalty timer for SHO

failure after down rate



Contents









Neighboring Cell Combination Algorithm

Cell A Cell B Cell C

Cell A Cell B Cell C A B C

Firstly, the cells in the active set are added.

Secondly, the neighboring cells of cell A are added.

After that, the neighboring cells of cell B are added.

Finally, the neighboring cells of cell C are added.

Cell A, Cell B and Cell C are in active set. Cell A is the best cell. Cell B Ec/No is greater than Cell C.


Parameters of Neighboring Cell Combination Algorithm HO_MC_NCELL_COMBINE_SWITCH

Parameter name: Neighboring Cell Combination Switch

Recommended value: ON

NprioFlag

Parameter name: The flag of the priority

Recommended value: FALSE

Nprio

Parameter name: the priority of the neighboring cell

Recommended value: None


Contents






Signaling Procedures for Intra-Frequency Handover There are five types of signaling procedures

for intra-frequency handover:

Intra-NodeB Intra-Frequency Soft Handover

Intra-RNC Inter-NodeB Intra-Frequency Soft Handover

Inter-RNC Intra-Frequency Soft Handover

Intra-RNC Inter-NodeB Intra-Frequency Hard Handover

Inter-RNC Intra-Frequency Hard Handover


Intra-NodeB Intra-Frequency Soft Handover


Intra-RNC Inter-NodeB Intra-Frequency Soft Handover


Inter-RNC Intra-Frequency Soft Handover


Intra-RNC Inter-NodeB Intra-Frequency Hard Handover


Inter-RNC Intra-Frequency Hard Handover


Contents





Contents


1. Inter-Frequency Handover Overview

2. Inter-Frequency Handover Procedure

3. Signaling Procedures for Inter-Frequency Handover


Inter-Frequency Handover Types The carrier frequency of the current cell and target

cell are different

Based on the triggering causes of handover, inter-

frequency handover can be categorized into two

types:

Coverage-based inter-frequency handover

Load-based inter-frequency handover


Contents




1. Coverage-based Inter-Frequency Handover

2. Load-based Inter-Frequency Handover

3. Blind Handover based on Event 1F

4. Inter-Frequency anti-Ping-Pong



Coverage-based Inter-Frequency Handover


Coverage-based Inter-Frequency Handover - Triggering Phase Triggering event:

2D event:

The estimated quality of the currently used frequency is

below a certain threshold

2F event:


above a certain threshold


Compressed Mode Purpose

Measure the inter-frequency cell or inter-RAT cell under FDD mode

Categories Downlink compressed mode

Uplink compressed mode

Realization Methods SF/2

Higher layer scheduling


Coverage-based Inter-Frequency Handover Events 2D event:


formula:QUsed ≤ TUsed2d - H2d/2


Parameters of Inter-Frequency Handover InterFreqCSThd2DEcN0

Parameter name: Inter-freq CS measure start Ec/No THD


InterFreqR99PsThd2DEcN0

Parameter name: Inter-freq R99 PS measure start Ec/No

THD


InterFreqHThd2DEcN0

Parameter name: Inter-freq H measure start Ec/No THD



Parameters of Inter-Frequency Handover (Cont.) InterFreqCSThd2DRSCP

Parameter name: Inter-freq CS measure start RSCP THD

Recommended value: -95, namely -95dBm

InterFreqR99PsThd2DRSCP

Parameter name: Inter-freq R99 PS measure start RSCP

THD


InterFreqHThd2DRSCP

Parameter name: Inter-freq H measure start RSCP THD



Parameters of Inter-Frequency Handover (Cont.) HystFor2D

Parameter name: 2D hysteresis


TimeToTrig2D

Parameter name: 2D event trigger delay time



Coverage-based Inter-Frequency Handover Events (Cont.) 2F event

Event 2F is triggered on the basis of the following

formula:

QUsed ≥ TUsed2f +

H2f/2


Parameters of Inter-Frequency Handover (Cont.) InterFreqCSThd2FEcN0

Parameter name: Inter-freq CS measure stop Ec/No THD


InterFreqR99PsThd2FEcN0

Parameter name: Inter-freq R99 PS measure stop Ec/No

THD


InterFreqHThd2FEcN0

Parameter name: Inter-freq H measure stop Ec/No THD



Parameters of Inter-Frequency Handover (Cont.) InterFreqCSThd2FRSCP

Parameter name: Inter-freq CS measure stop RSCP THD


InterFreqR99PsThd2FRSCP

Parameter name: Inter-freq R99 PS measure stop RSCP

THD


InterFreqHThd2FRSCP

Parameter name: Inter-freq H measure stop RSCP THD



Parameters of Inter-Frequency Handover (Cont.) HystFor2F

Parameter name: 2F hysteresis


TimeToTrig2F

Parameter name: 2F event trigger delay time



Coverage-based Inter-Frequency Handover - Measurement Phase Measurement control:

UE RNC

Measurement report (2D)

Physical Channel Recfg (CM)

Measurement control

Physical Channel Recfg Complet (CM)

UE RNC



Measurement control (RSCP)


Measurement control (Ec/No)

Periodical Reporting Event Reporting


Coverage-based Inter-Frequency Handover - Measurement Phase (Cont.) Measurement report:

Measurement report

Handover

Measurement report

UE RNC

Handover

Measurement report (2B)


UE RNC

Measurement report


Parameters of Inter-Frequency Handover (Cont.) InterFreqReportMode

Parameter name: Inter-frequency measure report mode

Recommended value: Periodical reporting

PrdReportInterval

Parameter name: Inter-frequency measure periodical rpt

period


InterFreqMeasTime

Parameter name: Inter-freq measure timer length



Coverage-based Inter-Frequency Handover - Decision Phase The coverage-based inter-frequency handovers are

categorized into two types according to the following

two measurement report modes:

periodical measurement report mode

event-triggered measurement report mode

Each mode corresponds to a different decision and

execution procedure


Coverage-based Inter-Frequency Handover - Decision Phase (Cont.) Periodical measurement report mode:

RNC decide whether both the CPICH Ec/No value and CPICH RSCP

value of the pilot signal of the target cell meet the requirement of

inter-frequency handover. The evaluation formula is listed below:

M other_Freq + CIOother_Freq ≥ Tother_Freq + H/2

Start the hard handover time-to-trigger timer, which is configured

through the parameter TimeToTrigForPrdInterFreq

If M other_Freq + CIOother_Freq < Tother_Freq - H/2, stop the

timer

Select the cells in sequence, that is, from high quality cells to low

quality ones, to initiate inter-frequency handover in the cells

where the hard handover time-to-trigger timer expires


Coverage-based Inter-Frequency Handover - Decision Phase (Cont.) Periodical measurement report mode:


Parameters of Inter-Frequency Handover (Cont.) CIO



CIOOffset




Parameters of Inter-Frequency Handover (Cont.) HystForPrdInterFreq

Parameter name: HHO hysteresis


TimeToTrigForPrdInterFreq

Parameter name: HHO period trigger delay time

Recommended value: 0, namely 0ms


Coverage-based Inter-Frequency Handover - Decision Phase (Cont.) Event-triggered measurement report mode:

After receiving the event 2B measurement report, the

RNC starts the following procedure:

Add all the pilot cells that trigger event 2B to a cell set

and arrange the cells according to the measurement

quality of CPICH_Ec/No in descending order

Select the cells in turn from the cell set to perform inter-

frequency handover


Coverage-based Inter-Frequency Handover - Decision Phase (Cont.) 2B event:

The estimated quality of the currently used frequency

is below a certain threshold and the estimated quality

of a non-used frequency is above a certain threshold

Event 2B is triggered on the basis of the following

formula:QNoused ≥ TNoused2b +

H2b/2

QUsed ≤ TUsed2b - H2b/2


Parameters of Inter-Frequency Handover (Cont.) TargetFreqCsThdEcN0

Parameter name: Inter-freq CS target frequency trigger

Ec/No THD


UsedFreqCSThdEcN0

Parameter name: Inter-freq CS Used frequency trigger

Ec/No THD



Parameters of Inter-Frequency Handover (Cont.)

Objective Target Cell Used Cell

CS Ec/No

threshold

-12, namely -

12dB

-12, namely -

12dB

PS Ec/No

threshold

-12, namely -

12dB

-12, namely -

12dB

H Ec/No

threshold

-12, namely -

12dB

-12, namely -

12dB

CS RSCP

threshold

-92, namely -

92dBm

-92, namely -

92dBm

PS RSCP

threshold

-92, namely -

92dBm

-92, namely -

92dBm

H RSCP threshold -92, namely -

92dBm

-92, namely -

92dBm

Recommended values of 2B event:


Parameters of Inter-Frequency Handover (Cont.) HystFor2B

Parameter name: 2B hysteresis


TimeToTrig2B

Parameter name: 2B event trigger delay time



Contents










Load-based Inter-Frequency Handover


Load-based Inter-Frequency Handover - Triggering Phase Current cell

Heavy load

Target cell

Light load

Blind handover flag is true

Target user

User with lower integrated priority


Parameters of Inter-Frequency Handover (Cont.) BlindHOFlag

Parameter name: Blind handover flag

Recommended value: False


Load-based Inter-Frequency Handover - Decision Phase Step 1: Based on the handover state, the RNC determines

how to trigger an inter-frequency blind handover:

Perform direct blind handover, go to step 2

Perform conditional blind handover, go to step 3

Do not perform blind handover

Step 2: The RNC check whether the conditions of direct blind

handover are met or not. If yes, UE perform direct blind

handover. Otherwise, go to step 3

Step 3: The RNC check whether the conditions of conditional

blind handover are met or not. If yes, UE perform conditional

blind handover. Otherwise, not perform blind handover


Parameters of Inter-Frequency Handover (Cont.) HO_ALGO_LDR_ALLOW_SHO_SWITCH

Parameter name: HandOver switch


BlindHOQualityCondition

Parameter name: Blind handover condition



Parameters of Inter-Frequency Handover (Cont.) BlindHOIntrafreqMRInterval

Parameter name: Intrafrequency measurement report

interval of blind HO


BlindHOIntrafreqMRAmount

Parameter name: Intrafrequency measurement report

amount of blind handover

Recommended value: D2, namely 2 times


Contents










Blind Handover based on Event 1F

Blind handover in inter-frequency handover:

Load-based handover

Speed-based handover from micro cell to macro cell

1F event triggered inter-frequency handover


Blind Handover based on Event 1F (Cont.) 1F event:

A PCPICH becomes worse than an absolute threshold


formula:MOld ≤ T1f - H1f/2


Parameters of Inter-Frequency Handover (Cont.) IntraAblThdFor1FecNo

Parameter name: 1F event absolute EcNo threshold


IntraAblThdFor1FRSCP

Parameter name: 1F event absolute RSCP threshold



Parameters of Inter-Frequency Handover (Cont.) Hystfor1F

Parameter name: 1F hysteresis


TrigTime1F

Parameter name: 1F event trigger delay time


BlindHORSCP1FThreshold

Parameter name: 1F event blind handover trigger

condition



Contents





2. QoS-based Inter-Frequency Handover


4. Speed-based Inter-Frequency Handover



7. Inter-Frequency Handover Retry



Inter-Frequency anti-Ping-Pong When a coverage-based inter-frequency handover or an

inter-frequency blind handover based on event 1F

occurs, the RNC starts the timer specified by

IFAntiPingpangTimerLength for the UE

When a non-coverage-based inter-frequency handover is

triggered, first, the RNC determines whether the timer

specified by IFAntiPingpangTimerLength expires

If the timer does not expire, the RNC cancels the handover

If the timer expires, the RNC performs the handover


Parameters of Inter-Frequency Handover (Cont.) IFAntiPingpangTimerLength

Parameter name: The timer length of anti pingpong

NCOV interfreq handover



Contents






Signaling Procedures for Inter-Frequency Handover Intra-RNC inter-frequency handover:


Signaling Procedures for Inter-Frequency Handover (Cont.) Inter-RNC inter-frequency handover:


Contents





Contents


1. Inter-RAT Handover Overview

2. Inter-RAT Handover Procedure

3. Signaling Procedures for Inter-RAT Handover


Inter-RAT Handover Scenarios


Inter-RAT Handover Types

Based on the triggering causes of handover, inter-

frequency handover can be categorized into three

types:

Coverage-based 3G to 2G handover

Load-based 3G to 2G handover

Service-based 3G to 2G handover


Inter-RAT Handover Preconditions Before handover, the RNC checks whether all the

following preconditions for the 3G to 2G handover

are met:

2G cell capability

Service capability

UE capability

Service handover indicator


Inter-RAT Handover Rules

Rules for coverage-based and QoS-based 3G to 2G

Handover:

Service handover indicator:

HO_TO_GSM_SHOULD_BE_PERFORM

HO_TO_GSM_SHOULD_NOT_BE_PERFORM

Three types of capability:

Refer to the following table


Inter-RAT Handover Rules (Cont.) Rules for Load-based 3G to 2G Handover:

Service handover indicator:


HO_TO_GSM_SHOULD_NOT_BE_PERFORM


Refer to the following table


Inter-RAT Handover Rules (Cont.) Rules for service-based 3G to 2G Handover

Service Handover Indicator



Refer to the table of load-based handover

Service switch


Contents




1. Coverage-based Inter-RAT Handover

2. Load-based Inter-RAT Handover

3. Service-based Inter-RAT Handover

4. UMTS to GSM Multimedia Fallback



Coverage-based Inter-RAT Handover


Coverage-based Inter-RAT Handover - Triggering Phase Triggering event:

2D event:


below a certain threshold

2F event:


above a certain threshold


Coverage-based Inter-RAT Handover Events 2D event:


formula:QUsed ≤ TUsed2d - H2d/2


Parameters of Inter-RAT Handover

Parameter Recommended Value

InterRATCSThd2DEcN0 -14, namely -14dB

InterRATR99PsThd2DEcN0 -15, namely -15dB

InterRATHThd2DEcN0 -15, namely-15dB

InterRATCSThd2DRSCP -100, namely -100dBm

InterRATR99PsThd2DRSCP -110, namely -110dBm

InterRATHThd2DRSCP -110, namely -110dBm

HystFor2D 4, namely 2dB

TimeToTrig2D D320, namely 320ms

Recommended values of 2D event:


Coverage-based Inter-RAT Handover Events (Cont.) 2F event:


formula:QUsed ≥ TUsed2f + H2f/2


Parameters of Inter-RAT Handover (Cont.)

Parameter Recommended Value

InterRATCSThd2FEcN0 -12, namely -12dB

InterRATR99PsThd2FEcN0 -13, namely -13dB

InterRATHThd2FEcN0 -13, namely-13dB

InterRATCSThd2FRSCP -97, namely -97dBm

InterRATR99PsThd2FRSCP -107, namely -107dBm

InterRATHThd2FRSCP -107, namely -107dBm

HystFor2F 4, namely 2dB

TimeToTrig2F D1280, namely 1280ms

Recommended values of 2F event:


Interoperability between Inter-RAT and Inter-Frequency Handover Inter-frequency measurement:

2D, 2F event

Inter-frequency neighboring cell

Inter-RAT measurement:

2D, 2F event

Inter-RAT neighboring cell

Measure inter-RAT neighbor?

Measure inter-RAT neighbor?

Measure inter-

frequency neighbor?

Measure inter-

frequency neighbor?


Parameters of Inter-RAT Handover (Cont.) InterFreqRATSwitch

Parameter name: Inter-freq and Inter-RAT coexist switch

Recommended value: SIMINTERFREQRAT

CoexistMeasThdChoice

Parameter name: InterFreq and InterRat coexist measure

threshold choice

Recommended value:

COEXIST_MEAS_THD_CHOICE_INTERFREQ


Coverage-based Inter-RAT Handover - Measurement Phase Measurement control:

UE RNC



Measurement control (RSCP or Ec/No)



Coverage-based Inter-RAT Handover - Measurement Phase (Cont.) Measurement report:

Measurement report

Handover

Measurement report

UE RNC

Handover

Measurement report (3A)


UE RNC

Measurement report


Parameters of Inter-RAT Handover (Cont.) InterRatReportMode

Parameter name: Inter-RAT report mode

Recommended value: PERIODICAL_REPORTING

InterRATPeriodReportInterval

Parameter name: Inter-RAT period report interval



Parameters of Inter-RAT Handover (Cont.) InterRATMeasTime

Parameter name: Inter-RAT measure timer length


MeasQuantityOf3A

Parameter name: 3A Measure Quantity

Recommended value: Auto, namely based on the 2D


Coverage-based Inter-RAT Handover - Decision Phase The coverage-based and QoS-based 3G to 2G

handover is categorized into two types according to

the following two measurement report modes:

Periodical measurement report mode

Event-triggered measurement report mode

Each mode corresponds to a different decision and

execution procedure


Coverage-based Inter-RAT Handover - Decision Phase (Cont.) Periodical measurement report mode:

RNC decide whether the quality of 2G cells meets the conditions of inter-RAT handover. The evaluation formula is listed below:

Mother_RAT + CIOother_RAT ≥ Tother_RAT + H/2

Start the evaluation of the cells that meet the quality requirement and start the time-to-trigger timer. If the measurement report meet the following formula and time-to-trigger timer does not expire, stop the time-to-trigger timer

Mother_RAT + CIOother_RAT < Tother_RAT - H/2

Select the cells in sequence, that is, from high quality cells to low quality ones, to initiate 3G to 2G handover in the cells where the handover time-to-trigger timer expires


Parameters of Inter-RAT Handover (Cont.) CIO



CIOOffset




Parameters of Inter-RAT Handover (Cont.) HystforInterRAT

Parameter name: Inter-RAT hysteresis


TimeToTrigForVerify

Parameter name: Time to trigger for verified GSM cell


TimeToTrigForNonVerify

Parameter name: Time to trigger for non-verified GSM cell



Coverage-based Inter-RAT Handover - Decision Phase (Cont.) Event-triggered measurement report mode:

After receiving the event 3A measurement report of 2G

cells, the RNC performs the following decision and

execution procedures:

Put all the 2G cells that trigger event 3A into a cell set and

arrange the cells according to the measurement quality in

descending order

Select the cells in sequence from the cell set to perform

inter-RAT handover


Coverage-based Inter-RAT Handover - Decision Phase (Cont.) 3A event:

The estimated quality of the currently used UTRAN

frequency is below a certain threshold and the

estimated quality of the other system is above a

certain threshold

Event 3A is triggered on the basis of the following

formula:QOtherRAT + CIOOtherRAT ≥ TOtherRAT +

H3a/2

QUsed ≤ TUsed - H3a/2


Parameters of Inter-RAT Handover (Cont.) UsedFreqCSThdEcN0

Parameter name: Inter-RAT CS Used frequency trigger

Ec/No THD


TargetRatCsThd

Parameter name: Inter-RAT CS handover decision THD

Recommended value: 16, namely -95dBm


Parameters of Inter-RAT Handover (Cont.)

Used cell Target cell

CS Ec/No threshold: -12, namely -12dB CS threshold: 16, namely -

95dBmPS Ec/No threshold: -13, namely -13dB

H Ec/No threshold: -13, namely -13dB PS threshold: 16, namely -

95dBmCS RSCP threshold: -97, namely -

97dBm

PS RSCP threshold: -107, namely -

107dBm H threshold: 16, namely -

95dBmH RSCP threshold: -107, namely -

107dBm

Recommended values of 3A event:


Parameters of Inter-RAT Handover (Cont.) Hystfor3A

Parameter name: 3A hysteresis


TrigTime3A

Parameter name: 3A event trigger delay time



Contents










Load-based Inter-RAT Handover


Parameters of Inter-RAT Handover (Cont.) InterRATMeasTime

Parameter name: Inter-RAT measure timer length



Load-based Inter-RAT Handover - Decision Phase 3C event:

The estimated quality of other system is above a

certain threshold

Event 3C is triggered on the basis of the following

formula:MOtherRAT + CIOOtherRAT ≥ TOtherRAT + H3c/2


Parameters of Inter-RAT Handover (Cont.) InterRATNCovHOCSThd

Parameter name: Inter-RAT CS handover decision THD


InterRATNCovHOPSThd

Parameter name: Inter-RAT PS handover decision THD



Parameters of Inter-RAT Handover (Cont.) Hystfor3C

Parameter name: 3C hysteresis


TrigTime3C

Parameter name: 3C event trigger delay time



Load-based Inter-RAT Handover - Execution Phase After receiving the event 3C measurement report of

2G cells, the RNC performs the following handover

decision and execution procedure:

Put all the 2G cells that trigger event 3C into a cell set

and arrange the cells according to the measurement

quality in descending order

Select the cells in sequence from the cell set


Parameters of Inter-RAT Handover (Cont.) SndLdInfo2GsmInd

Parameter name: Send Load Info to GSM Ind


NcovHoOn2GldInd

Parameter name: NCOV Reloc Ind based on GSM cell

load



Parameters of Inter-RAT Handover (Cont.) CSHOOut2GloadThd

Parameter name: CS domain Reloc GSM load THD

Recommended value: 80, namely 80%

PSHOOut2GloadThd

Parameter name: PS domain Reloc GSM load THD

Recommended value: 60, namely 60%


Parameters of Inter-RAT Handover (Cont.) InterRATHOAttempts

Parameter name: Inter-RAT handover max attempt

times



Contents










Service-based Inter-RAT Handover


Parameters of Inter-RAT Handover (Cont.) CSServiceHOSwitch

Parameter name: Inter-RAT CS handover switch

Recommended value: OFF

PSServiceHOSwitch

Parameter name: Inter-RAT PS handover switch

Recommended value: OFF


Contents










UMTS to GSM Multimedia Fallback

GSMWCDMA

VP AMR AMR

VP service:

Speech

Video

AMR

service:

Speech


Contents






Signaling Procedures for CS Inter-RAT Handover

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OWO113030 WCDMA RAN11 Handover Algorithm and Parameters ISSUE1.02

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