Download - 10- OWJ200106 WCDMA Handover Principal (With Comment) ISSUE1.0

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Copyright 2006 Huawei Technologies Co., Ltd. All rights reserved.

C!"AHandover

#rinciple


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Page2Copyright 2006 Huawei Technologies Co., Ltd. All rights reserved.

$oreword

hy mo%ile systems need handover&

't is decided %y the characters o( mo%ile system)

The mo%ility o( *+

The mo%ile system is composed %y cells which the

coverage a%ility is limited.

#roviding the continuous service in mo%ile system

is the %asic element in o-.


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%/ectives

*pon completion o( this course, you will %e a%le to)

The %asic denitions o( Handover

The algorithms o( handover decision

The handover 1ow

The parameters o( handover


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Contents

1. Introduction of Handover

2. "easurement o( Handover

. The 3asic Handovers


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The #urpose o( Handover

#roviding the continuous service in mo%ile system is the%asic element in o-.

The load %alance) sharing the resource

The hierarchy divided %y speed and service) high

e4ciency o( using resource


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The 3asic Concepts o(Handover Active -et "onitored -et !etected set +vent reporting

+vent reporting to #eriodic reporting

#eriodic reporting 5adio Lin 75L8 5adio Lin -et 75L-8 Com%ination way)

ma9imum ratio com%ination selection com%ination

The so(t handover gain C#'CH -o(t handover, so(ter handover, hard handover


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The Categories o( Handover

According to the signaling characters) -o(t handover 7so(ter handover8

Hard handover

According to the properties o( source cell and target cell 'ntra:(re;uency handover

'nter:(re;uency handover

'nter:system handover 7*"T- -"8

According to the purpose o( handover 3ased on Coverage

3ased on Load 7ptional8

3ased on mo%ility o( *+ 7ptional8

3ased on -ervice 7ptional8



The Characters o( !i?erentHandovers

'tem -o(t Handover Hard Handover

The num%ers o( 5L in

active set a(ter

handover

-everal ne

'nterruption during

handover

@o es

The (re;uencies o(

cells

nly happened in

'ntra:(re;uency

cells

Can %e happened in 'ntra:

(re;uency cells or 'nter:

(re;uency cells

Comparison %etween so(t handover and hard

handover)



The Characters o( !i?erentHandovers Comparison %etween so(t handover and so(ter

handover

!uring so(ter handover, the uplin signaling are com%ined

in @ode3 %y ma9imum ratio com%ination, %ut during so(thandover they are com%ined in 5@C %y selection

com%ination

Compare to later one, the ma9imum ration com%ination can

get more gain. -o the per(ormance o( ma9imum ration

com%ination is %etter

-ince so(ter handover is completed in @ode3, it do not

consume transport resource o( 'u%



RNC

NodeB 2NodeB 1

-o(t Handover



RNC (WFMR)

NodeB

-o(ter Handover



Hard Handover

RNC

NodeB 2NodeB 1



Three -teps o( Handover

Decision

Execute

Measurement


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uestions

The di?erences among -o(t handover, so(terhandover and hard handover

Typical application scenarios


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-ummary

This chapter (ocus on the purpose o( handovers andthe categories o( handover in C!"A.


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Contents

B. 'ntroduction o( Handover

2. Measurement of Handover

. The 3asic Handovers


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Contents


2.1 Measurement control and measurement report

2.2 The %asic denitions o( measurement

2. "easurement event

2. Compressed mode


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Measurement Control, normal case

UE UTRN

ME!UREMENT C"NTR"#

"easurement Control


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"easurement Control


UE UTRN

ME!UREMENT C"NTR"#


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UE UTRN

ME!UREMENT RE$"RT

"easurement 5eport


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Contents


2.B "easurement control and measurement report

2.2 The basic denitions of measurement


2. Compressed mode


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The 3asic Concepts o("easurement The measurement values o( Handover

-o(t handover and 'ntra:(re;uency hard handover ) C#'CH 5-C#,

C#'CH +cD@0, #ath loss

'nter:(re;uency C#'CH 5-C#, C#'CH +cD@0

'nter:system>-" Carrier 5--', 3-'C 'dentication, 3-'C

5econrmation

The reporting methods o( measurement

#eriodic reporting

+vent reporting

The events o( reporting 'ntra:(re;uency events BA,B3,BC,B!,B$

'nter:(re;uency events 2!,2$,23,2C

'nter:system events A,C


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"easurement "odel

#a%er 1

&ilterin'#a%er

&ilterin'Ealuation

o& re*ortin'

criteria

DB C

C+

*arameters *arameters


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5eporting Criterion

),2/(10)1(1010 11

aBest

N

i

iNew HRLogMWMLogWLogM

A

++

=

),2/(10)1(1010 11

aBest

N

i

iNew HRLogMWMLogWLogMA

+

=

5eporting Criterion !ecision (ormula) (or e9ample, BA event )

#ath Loss

ther measurement


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Eey #arameters


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Contents




2.3 Measurement event

2. Compressed mode


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'ntra:(re;uency "easurement+vents

'ntra:(re;uency measurement report events areidentied with BF

BA ) A primary pilot channel enters the reporting range.

hen the active set o( *+ is (ull, *+ stops reporting BA

eventG

B3 ) A primary pilot channel leaves the reporting rangeG

BC ) The primary pilot channel in a non active set is

%etter than the primary pilot channel in an active setG

B! ) The %est cell changesG

B+ ) The measurement value o( a primary pilot channel

e9ceeds the a%solute threshold


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'nter:(re;uency "easurement+vents

'nter:(re;uency measurement events are identiedwith 2F

23 ) The estimated ;uality value o( the used (re;uency

is lower than a certain threshold, and that o( the non:

used (re;uency is higher than a certain thresholdG

2C ) The estimated ;uality value o( the non:used

(re;uency is higher than a certain thresholdG

2! ) The estimated ;uality value o( the used (re;uency

is lower than a certain threshold

2$ ) The estimated ;uality value o( the used (re;uency

is higher than a certain threshold


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'nter:system "easurement+vents

'nter:system measurement events are identied withF

A ) The estimated ;uality value o( the used *T5A@

(re;uency is lower than a certain threshold, and that o(

the other system is higher than a certain threshold

C ) The estimated ;uality value o( the other system is

higher than a certain threshold


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Contents





2.4 Compressed mode


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Compressed "ode -etch "ap

One frame

(10 ms) Transmission gap available forinter-frequency measurements


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The realiation "ethods o(

Compressed mode

5ealiation "ethods -$D2

5ate matchingDpuncturing

Higher layer scheduling


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-ummary

This chapter covers intra:(re;uency measurement,inter:(re;uency measurement, inter:system

measurement and *+ internal measurement (rom

their denitions and application scenarios


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Contents

B. 'ntroduction o( Handover


3. The Basic Handovers


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Contents

. The 3asic Handovers3.1 oft Handover

.2 'ntra:(re;uency Hard Handover

. 'nter:(re;uency Hard Handover

. 'nter:system Hard Handover


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3rie( 'ntroduction o( -o(tHandover

Characters o( -o(t Handover !uring handover, *+ has several 5Ls with di?erent

cells : active set

The handover among di?erent cells which are in same

5L- can %e so(ter handover

-o(t handover)

I -election com%ination in uplin

I "a9imum com%ination in downlin

-o(ter handover

I "a9imum com%ination in uplin and downlin


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3rie( 'ntroduction o( -o(tHandover

Advantages -o(t handover gain

Load %alance

!ecrease the possi%ility o( call drop caused %y ping:pong

handover

!isadvantages

"ore resource needed in downlin, especially (or the code

resource o( 3+ service

*sually, the gain o( downlin power is negative

hen the downlin power (rom di?erent cells is not %alanced,

it will %ring side:e?ect


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"easurement o( -o(t Handover

The measurement o( so(t handoverDso(ter handover "easurement value C#'CH 5-C# C#'CH

+cD@o #athloss

#rocess o( "easurement Layer B lter, Layer lter

5eporting way

#eriodic reporting

+vent reporting

I +vent type BA B3 BC B! B$

I *+ measures the time di?erence %etween C$@ and -$@

I 5eporting rules) trigger condition, 5elative threshold, A%solute

threshold, Hysteresis, Time to trigger

+vent reporting to periodic reporting


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The !ecision Algorithm o( -o(tHandover

-o(tDso(ter handover decision BA ) 5adio Lin Addition

B3 ) 5adio Lin 5emoval

BC ) Com%ined 5adio Lin Addition and 5emoval B! ) change %est cell


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The +9ecution o( -o(tHandover

-o(t handover e9ecution The update principal o( measurement control

Congure the neigh%or cells and the parameters

according to %est cell

5LC mode A" mode is used (or measurement control

*" mode is used (or measurement report

The compensation and restriction o( so(t handover

$rom event reporting to periodic reporting


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-o(t Handover $low 7add 5L8


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-o(t Handover $low 7del 5L8


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Eey #arameters

5elative threshold Time to trigger

Layer lter coe4cient

A%solute threshold o( so(t handover


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Contents

. The 3asic Handovers.B -o(t Handover

3.2 Intra!fre"uenc# Hard Handover

. 'nter:(re;uency Hard Handover. 'nter:system Hard Handover


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3rie( 'ntroduction o( 'ntra:(re;uency

Hard Handover

Characters *+ only has one 5L with one cell in the process o( handover

!isconnect *+ with the original cell, then hand it over to target cell

The woring (re;uency o( source cell and target cell are same

Advantages

+nhance the using e4ciency o( the J-$ code and hardwareresource

!isadvantages

High call drop possi%ility %ecause o( the intra:(re;uencyinter(erence

Application scenarios ithout 'ur inter(ace %etween two 5@Cs or the 'ur inter(ace /am

7only happened in inter:5@C handover8

The di?erent strategies can %e used (or di?erent conditions, suchas code resource condition, the o- condition and so no


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The "easurement, !ecision and+9ecution o( 'ntra:(re;uency HardHandover "easurement

-imilar to so(t handover

!ecision B! event

+9ecution *+ reports C$@:-$@ in(ormation

-ynchroniation hard handover *se the original !$$ value Continuous C$@

*+ does not report C$@:-$@ in(ormation The hard handover %ased on timing 5e:congure !$$ Calculate C$@ according to !$$


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The "easurement, !ecision and+9ecution o( 'ntra:(re;uency HardHandover "easurement

-imilar to so(t handover

!ecision B! event

+9ecution *+ reports C$@:-$@ in(ormation

-ynchroniation hard handover *se the original !$$ value Continuous C$@

*+ does not report C$@:-$@ in(ormation The hard handover %ased on timing 5e:congure !$$ Calculate C$@ according to !$$


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'ntra:(re;uency Hard Handover$low

UE

1.RADIO LINK SETUP REQUEST

TargetNODE

S!"r#eNODE SRN$

2. RADIO LINK SETUP RESPONSE

3.AL$AP e%ta&'(%)

4. P*+SI$AL $*ANNEL RE$ON,I-URATION

5. RADIO LINK

,AILURE INDI$ATION

6. P*+SI$AL $*ANNEL RE$ON,I-URATION $OPLETE

7. RADIO LINK

DELETION REQUEST

8. RADIO LINK

DELETION RESPONSE

9.AL$AP re'ea%e


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Eey #arameters

Handover decision threshold %ased on 3+ speed *+ should do so(t handover when the speed o( 3+

service is less than the threshold.

*+ should do intra:(re;uency hard handover when the

speed o( 3+ service is greater than the threshold.

The parameters a%out B! event

Time to trigger, hysteresis

The parameters should %e set accord with the os


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Contents



3.3 Inter!fre"uenc# Hard Handover. 'nter:system Hard Handover


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The 3rie( 'ntroduction o( 'nter:

(re;uency Hard Handover Characters

The woring (re;uency is di?erent a(ter handover

The compressed mode needed i( the *+ only has one

receiver

*sually, the timing re:initiation hard handover is used

(or hard handover

Application scenarios

!isconnected coverage

Handover %ased on load

Hierarchy cells


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"easurement Jalues and+vents The 'nter:(re;uency hard handover measurement

values

"easurement values

C#'CH 5-C# C#'CH +cD@0

!i?erent handover purpose (or di?erent measurement

type

'n the edge o( carrier coverage) C#'CH 5-C#

'n the center o( carrier coverage) C#'CH +cD@o


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Compressed "ode 'nitiation

Conditions (or measurement initiated 2! event ) The estimated ;uality value o( the used

(re;uency is lower than a certain threshold

Conditions (or "easurement stopping

2$ event ) The estimated ;uality value o( the used

(re;uency is higher than a certain threshold


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Cells Hierarchy Algorithm 3ased

on *+ "oving -peed hen *+ is in one o( the hierarchy cells, the moving

speed estimation algorithm is initiated

Handover events in a while decides whether the speed

o( *+ satises the current cell hierarchy condition *+Ks moving speed decided the result


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!ecisionAlgorithm The inter:(re;uency hard handover decision

The coverage triggers the handover

23 event

I the ;uality in the used (re;uency is lower than a%solute

threshold, %ut the ;uality in another non:used (re;uency is

higher than another a%solute threshold.

The load triggers handover

2C event

I the ;uality in another (re;uency is higher than an a%solute

threshold


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'nter:(re;uency Hard Handover-ignaling $low

UE

1.RADIO LINK SETUP REQUEST

TargetNODE

S!"r#eNODE SRN$

2. RADIO LINK SETUP RESPONSE

3.AL$AP e%ta&'(%)e/

4. P*+SI$AL $*ANNEL RE$ON,I-URATION

5. RADIO LINK

,AILURE INDI$ATION

6. P*+SI$AL $*ANNEL RE$ON,I-URATION $OPLETE

7. RADIO LINK

DELETION REQUEST

8. RADIO LINKDELETION RESPONSE

9.AL$AP re'ea%e/


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Eey #arameters 7'8 'nter:(re;uency coverage handover parameters

'nter:(re;uency measurement reporting) periodic reporting or

event reporting

'nter:(re;uency measurement values) C#'CH +cD@o or C#'CH 5-C#

'nter:(re;uency measurement layer lter coe4cient, delay

trigger time and hysteresis

'nter:(re;uency initiated and stopped threshold) Considering the

di?erent demands o( C#'CH +cD@o and C#'CH 5-C# (or #- domain

and C- domain, the di?erent 2! and 2$ parameters are congured.

'nter:(re;uency handover %ased on coverage) the ;uality threshold

o( target cell

*sing (re;uency ;uality threshold in inter:(re;uency hard handover

The minimum access threshold (or inter:(re;uency handover


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Eey #arameters 7''8

'nter:(re;uency handover parameters caused %ynon:coverage a%ility

'nter:(re;uency measurement layer lter coe4cient,

delay trigger time and hysteresis

'nter:(re;uency handover %ased on non:coverage

a%ility


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Contents



. 'nter:(re;uency Hard Handover

3.4 Inter!s#stem Hard Handover


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The 3rie( 'ntroduction o( 'nter:

system Hard Handover Application scenarios C!"A $!! -"

Characters !i?erent radio access technology is used a(ter handover *sually, compressed mode should %e used to help the

measurement Advantages

$or coverage, it can solve the pro%lems (rom one system toanother system

$or capacity, it can enhance the utiliing e4ciency o( olde;uipments72>:=>8

!isadvantages The 1ow is complicated, and it demands higher

compati%ility (or e;uipments !emands more complicated *+


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Compressed "ode

'nitiated

The inter:system measurement 7>-" measurement8 "easurement type)

>-" Carrier 5--'

3-'C 'dentication

3-'C 5econrmation

The process o( measurement) layer B lter, layer lter

"easurement reporting

+vent reporting

I 2! +vent) initiate >-" measurement

I 2$ +vent) stop >-" measurement


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!ecision Algorithm

'nter:system handover caused %y coverage +vent reporting)

A eventThe estimated ;uality value o( the used *T5A@

(re;uency is lower than a certain threshold, and that o( the

other system is higher than a certain threshold

#eriodic reporting)

+valuation According to the periodic reported >-" 5--'

measurement value and the 3-'C conrming state o( target

cell o( >-" system, and meanwhile the *+ evaluates the

>-" 5--' o( target cell is greater than the a%solute

threshold, then consider the cell conrmed %y 3-'C


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!ecisionAlgorithm

'nter:system handover caused %y non:coverage +vent reporting

C event) The estimated ;uality value o( the other

system is higher than a a%solute threshold


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1. elocation

equire! 2. "repare#an!over

$. #an!overequest

%. #an!overequest &c'

12. (u elease

)omman!

1$. (u elease)omplete 1%. *en! +n!

*ignal esponse

,. "repare#an!over-. elocation

)omman!

.DCCH

/ #an!overfrom T& )omman!

. #an!over3etect

4. #an!over )omplete

10. #an!over)omplete

11. *en!

+n!

+ o!e 5 *) ) MSC 5*)

'nter:system Handover $low


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Eey #arameters 7'8

'nter:system handover caused %y coverage parameters 'nter:system measurement initiated and stopped threshold)

Considering the di?erent demands o( C#'CH +cD@o andC#'CH 5-C# (or #- domain and C- domain, the di?erent 2!and 2$ parameters are congured

'nter:system measurement values 72!, 2$8 C#'CH +cD@o

C#'CH 5-C#

3-'C conrmed 7ptional8

'nter:system handover caused %y coverage parameters

congure the >-" 5--' threshold o( C- domain and #- domainseparately

*sing inter:system (re;uency ;uality handover threshold

Congure the delay trigger time, hysteresis (or each event


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Eey #arameters 7''8

'nter:system handover caused %y non:coverageparameters

The period o( inter:system measurement report

The decision threshold (or inter:system handover)

congure the C-, #-, signaling separately

Time delay trigger ) congure 3-'C with

acnowledged and unacnowledged mode

'nter:(re;uency measurement layer ltercoe4cient and hysteresis

#enalty time


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uestions

hat are the di?erences %etween so(t handover andso(ter handover&

hat is compressed mode&

!raw out the hard handover signaling 1ow.


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-ummary

This chapter (ocus on the %asic handovers in C!"A)so(t handover, so(ter handover, intra:(re;uency hard

handover, inter:(re;uency hard handover and inter:

system hard handover. 't also introduced the

application scenarios (or these di?erent handovers "eanwhile, compressed mode is introduced in this

chapter


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