OWJ200106 WCDMA Handover Principal (With Comment) ISSUE1.0

8/9/2019 OWJ200106 WCDMA Handover Principal (With Comment) ISSUE1.0

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

C!"AHandover#rinciples


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$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 de1nitions o( Handover

The algorithms o( handover decision

The handover ow The parameters o( handover


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Contents1. Introduction of Handover

2. "easurement o( Handover

. The 4asic 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

e ciency o( using resource


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The 4asic Concepts o(Handover

Active -et"onitored -et!etected set+vent reporting

+vent reporting to #eriodic reporting

#eriodic reporting7adio Lin8 97L:7adio Lin8 -et 97L-:Com%ination way)

ma;imum ratio com%inationselection com%ination

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


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Copyright 2006 Huawei Technologies Co., Ltd. All rights reserved. #ageuency handover

'nter=system handover 9*"T- ?=@ -":

According to the purpose o( handover4ased on Coverage

4ased on Load 9/ptional:

4ased on mo%ility o( *+ 9/ptional:

4ased on -ervice 9/ptional:


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The Characters o( !i erentHandovers

'tem -o(t Handover Hard Handover

The num%ers o( 7L in

active set a(ter

handover

-everal /ne

'nterruption during

handover

Do Ees

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)


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The Characters o( !i erentHandovers

Comparison %etween so(t handover and so(terhandover

!uring so(ter handover, the uplin8 signaling are com%ined

in Dode4 %y ma;imum ratio com%ination, %ut during so(thandover they are com%ined in 7DC %y selection

com%ination

Compare to later one, the ma;imum ration com%ination can

get more gain. -o the per(ormance o( ma;imum ration

com%ination is %etter

-ince so(ter handover is completed in Dode4, it do not

consume transport resource o( 'u%


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RNC

NodeB 2NodeB 1

-o(t Handover


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RNC (WFMR)

NodeB

-o(ter Handover


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Hard Handover

RNC

NodeB 2NodeB 1


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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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ContentsG. 'ntroduction o( Handover2. Measurement of Handover

. The 4asic Handovers


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Measurement Control, normal case

UE UTR N

ME !UREMENT C"NTR"#

"easurement Control


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"easurement Control


UE UTR N

ME !UREMENT C"NTR"#


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UE UTR N

ME !UREMENT RE$"RT

"easurement 7eport


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Copyright 2006 Huawei Technologies Co., Ltd. All rights reserved. #age2G

Contents2. "easurement o( Handover

2.G "easurement control and measurement report

2.2 The basic de nitions of measurement

2. "easurement event2.3 Compressed mode


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"easurement "odel

#a%er 1&ilterin'

#a%er &ilterin' E aluation

o& re*ortin'criteria

DB C

C+

*arameters *arameters


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7eporting Criterion

),2/(10)1(1010 11

a Best

N

ii New H R LogM W M Log W LogM

A

++

=

),2/(10)1(1010 11

a Best

N

ii New H R LogM W M Log W LogM

A

+

=

7eporting Criterion !ecision (ormula) (or e;ample, GA event )

#ath Loss

/ther measurement


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Iey #arameters


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Contents2. "easurement o( Handover

2.G "easurement control and measurement report

2.2 The %asic de1nitions o( measurement

2.3 Measurement event2.3 Compressed mode


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'nter=(re>uency "easurement+vents

'nter=(re>uency measurement events are identi1edwith 2J

24 ) The estimated >uality value o( the used (re>uencyis lower than a certain threshold, and that o( the non=used (re>uency is higher than a certain thresholdK

2C ) The estimated >uality value o( the non=used(re>uency is higher than a certain thresholdK

2! ) The estimated >uality value o( the used (re>uencyis lower than a certain threshold

2$ ) The estimated >uality value o( the used (re>uencyis higher than a certain threshold


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'nter=system "easurement+vents

'nter=system measurement events are identi1ed withJ

A ) The estimated >uality value o( the used *T7AD

(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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The #urpose o( Compressedmode

#urpose"easure the inter=(re>uency cell or inter=system cell

under $!! mode

Categories

!ownlin8 compressed

*plin8 compressed


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The reali ation "ethods o(

Compressed mode7eali ation "ethods-$ 2

7ate matching puncturing

Higher layer scheduling


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uestions

How many events are there in intra=(re>uencymeasurement& hat are they&

How many events are there in *+ internal

measurement&

How many events are there in inter=(re>uency

measurement& hat are they&


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-ummary

This chapter covers intra=(re>uency measurement,inter=(re>uency measurement, inter=systemmeasurement and *+ internal measurement (romtheir de1nitions and application scenarios


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Contents

G. 'ntroduction o( Handover2. "easurement o( Handover

3. The Basic Handovers


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4rie( '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 downlin8, especially (or the code

resource o( 4+ service

*sually, the gain o( downlin8 power is negative

hen the downlin8 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 handover so(ter handover "easurement value C#'CH 7-C# C#'CH

+c Do #athloss

#rocess o( "easurement Layer G 1lter, Layer 1lter

7eporting way

#eriodic reporting

+vent reporting

M +vent type GA G4 GC G! G$

M *+ measures the time di erence %etween C$D and -$D

M 7eporting rules) trigger condition, 7elative threshold, A%solute

threshold, Hysteresis, Time to trigger

+vent reporting to periodic reporting


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The !ecision Algorithm o( -o(tHandover

-o(t so(ter handover decisionGA ) 7adio Lin8 Addition

G4 ) 7adio Lin8 7emoval

GC ) Com%ined 7adio Lin8 Addition and 7emovalG! ) change %est cell


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The +;ecution o( -o(tHandover

-o(t handover e;ecution The update principal o( measurement control

Con1gure the neigh%or cells and the parametersaccording to %est cell

7LC modeA" 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 9add 7L:


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Iey #arameters

7elative threshold Time to trigger

Layer 1lter coe cient

A%solute threshold o( so(t handover


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Contents

. The 4asic Handovers.G -o(t Handover

3.2 Intra!fre"uenc# Hard Handover

. 'nter=(re>uency Hard Handover

.3 'nter=system Hard Handover


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Hard HandoverCharacters*+ only has one 7L with one cell in the process o( handover!isconnect *+ with the original cell, then hand it over to target cell

The wor8ing (re>uency o( source cell and target cell are same

Advantages

+nhance the using e ciency o( the /N-$ code and hardwareresource

!isadvantagesHigh call drop possi%ility %ecause o( the intra=(re>uencyinter(erence

Application scenariosithout 'ur inter(ace %etween two 7DCs or the 'ur inter(ace am9only happened in inter=7DC handover:

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+;ecution o( 'ntra=(re>uency HardHandover"easurement-imilar to so(t handover

!ecisionG! event

+;ecution*+ reports C$D=-$D in(ormation

-ynchroni ation hard handover*se the original !/$$ valueContinuous C$D

*+ does not report C$D=-$D in(ormation The hard handover %ased on timing7e=con1gure !/$$Calculate C$D according to !/$$


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Iey #arameters

Handover decision threshold %ased on 4+ speed*+ should do so(t handover when the speed o( 4+

service is less than the threshold.

*+ should do intra=(re>uency hard handover when the

speed o( 4+ service is greater than the threshold.

The parameters a%out G! event

Time to trigger, hysteresis

The parameters should %e set accord with the os


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Contents


.2 'ntra=(re>uency Hard Handover

3.3 Inter!fre"uenc# Hard Handover.3 'nter=system Hard Handover


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The 4rie( 'ntroduction o( 'nter=

(re>uency Hard HandoverCharacters The wor8ing (re>uency is di erent a(ter handover

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

*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 Nalues and+vents

The 'nter=(re>uency hard handover measurementvalues

"easurement values

C#'CH 7-C# C#'CH +c D0

!i erent handover purpose (or di erent measurement

type

'n the edge o( carrier coverage) C#'CH 7-C#

'n the center o( carrier coverage) C#'CH +c Do


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Compressed "ode 'nitiation

Conditions (or measurement initiated2! 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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Copyright 2006 Huawei Technologies Co., Ltd. All rights reserved. #age5uency hard handover decision

The coverage triggers the handover

24 event

Mthe >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 eventMthe >uality in another (re>uency is higher than an a%solute

threshold


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Iey #arameters 9'':

'nter=(re>uency handover parameters caused %ynon=coverage a%ility

'nter=(re>uency measurement layer 1lter coe cient,

delay trigger time and hysteresis

'nter=(re>uency handover %ased on non=coverage

a%ility


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Contents


.2 'ntra=(re>uency Hard Handover

. 'nter=(re>uency Hard Handover

3.4 Inter!s#stem Hard Handover


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The 4rie( 'ntroduction o( 'nter=

system Hard HandoverApplication scenariosC!"A $!! ? @ -"

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

Advantages$or coverage, it can solve the pro%lems (rom one system toanother system$or capacity, it can enhance the utili ing e ciency o( olde>uipments92 =@ :

!isadvantages The ow is complicated, and it demands highercompati%ility (or e>uipments!emands more complicated *+


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Compressed "ode'nitiated The inter=system measurement 9 -" measurement:"easurement type)

-" Carrier 7--'

4-'C 'denti1cation

4-'C 7econ1rmation

The process o( measurement) layer G 1lter, layer

1lter

"easurement reporting

+vent reporting

M2! +vent) initiate -" measurement

M2$ +vent) stop -" measurement


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!ecision Algorithm'nter=system handover caused %y coverage

+vent reporting)

A event The estimated >uality value o( the used *T7AD

(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 -" 7--'

measurement value and the 4-'C con1rming state o( target

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

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

threshold, then consider the cell con1rmed %y 4-'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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OWJ200106 WCDMA Handover Principal (With Comment) ISSUE1.0