Handover.doc

5/28/2018 Handover.doc

1/136

GSM BSS

Handover Contents

GSM BSS

HandoverFeature Parameter Description

Copyright Huawei Technologies Co., Ltd. 2010. All rights reserved.

No part of this document may be reproduced or transmitted in any form or by any means without prior written

consent of Huawei Technoo!ies Co"# $td"

Trademars and !ermissions

and other Huawei trademar%s are trademar%s of Huawei Technoo!ies Co"# $td"& other trademar%s and trade names mentioned in this document are the property of their respective

hoders"

"otice

The purchased products# services and features are stipuated by the commercia contract made between

Huawei and the customer" & or partia products# services and features described in this document may not

be within the purchased scope or the usa!e scope" 'ness otherwise a!reed by the contract# a statements#

information# and recommendations in this document are provided (&S )S* without warranties# !uarantees or

representations of any %ind# either e+press or impied"

The information in this document is sub,ect to chan!e without notice" -very effort has been made in the

preparation of this document to ensure accuracy of the contents# but a statements# information# and

recommendations in this document do not constitute the warranty of any %ind# e+press or impied"

)ssue ./ 01./.2.324.5 Huawei Proprietary and Confidentia

Copyri!ht 6 Huawei

Technoo!ies Co"# $td"

i


2/136

Contents

GSM BSS

Handover

Contents

1 Introduction.....................................................................................................................................1

/"/ Scope"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" /

/"/ Scope"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" /

/"1 )ntended &udience""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" /

/"1 )ntended &udience""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" /

/"4 Chan!e History"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" /

/"4 Chan!e History"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" /

2 Overview...........................................................................................................................................1

3 Technical Description......................................................................................................................1

4"/ Measurement 7eport Processin!""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""/

4"/ Measurement 7eport Processin!""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""/

4"1 Handover Preprocessin!""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" 1

4"1 Handover Preprocessin!""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" 1

4"4 Handover Decision Based on Handover &!orithm )""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""8

4"4 Handover Decision Based on Handover &!orithm )""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""8

4"4"/ 9uic% Handover""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" 8

4"4"/ 9uic% Handover""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" 8

4"4"1 T& Handover"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" /.

4"4"1 T& Handover"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" /.

4"4"4 B9 Handover""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" //

4"4"4 B9 Handover""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" //

4"4": 7apid $eve Drop Handover"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""/1

4"4": 7apid $eve Drop Handover"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""/1

4"4"; )nterference Handover"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""/1

4"4"; )nterference Handover"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""/1

4"4"3 Handover Due to No Downin% Measurement 7eport""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""/4

4"4"3 Handover Due to No Downin% Measurement 7eport""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""/4

4"4"< -nhanced Dua2Band Networ% Handover""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""/:

4"4"< -nhanced Dua2Band Networ% Handover""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""/:

4"4"8 $oad Handover"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" /3

4"4"8 $oad Handover"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" /3

4"4"= -nhanced $oad Handover"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""/8

4"4"= -nhanced $oad Handover"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""/8

4"4"/. -d!e Handover"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" /=

4"4"/. -d!e Handover"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" /=

4"4"// Fast2Movin! Micro Ce Handover""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""1.

4"4"// Fast2Movin! Micro Ce Handover""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""1.

4"4"/1 )nter2$ayer Handover""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" 11

ii Huawei Proprietary and Confidentia

Copyri!ht 6 Huawei


)ssue ./ 01./.2.324.5


3/136

GSM BSS

Handover Contents

4"4"/1 )nter2$ayer Handover""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" 11

4"4"/4 PBGT Handover""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" 14

4"4"/4 PBGT Handover""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" 14

4"4"/: &M7 Handover"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" 14

4"4"/: &M7 Handover"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" 14

4"4"/; SDCCH Handover"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" 1:

4"4"/; SDCCH Handover"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" 1:

4"4"/3 >ther Handovers"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" 1;

4"4"/3 >ther Handovers"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" 1;

4": Handover Decision Based on Handover &!orithm ))"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""1;

4": Handover Decision Based on Handover &!orithm ))"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""1;

4":"/ 9uic% Handover""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" 1

Penaty Time after T& H>

B9 Handover Penaty $eve after B9 H>Penaty Time after B9 H>

$oad handover0handovera!orithm ))5

Penaty Time on $oad H>

Penaty Iaue on $oad H>

&fter the fast2movin! micro ce handover is successfuy performed# penaty is performed on a thenei!hborin! ces of the micro ce" 7eated parameters are $&!":ALand $!&!"#$HT"

)f an MS fais to initiate an intra2ce &M7 TCHF to TCHH handover# it cannot initiate another intra2ce&M7 TCHF to TCHH handover within T#/A/5H!"#$H"

)n handover a!orithm ))# after the interference handover is initiated# this handover is not aowed to beinitiated a!ain within #"T5H+!"T#/re!ardess of whether the handover is successfu ornot"

&fter the >$ subce to '$ subce handover within an enhanced concentric ce is successfu# thehandover from '$ subce to >$ subce is not aowed within T++H+!"T#/"

&fter the >$ ce to '$ ce handover in the enhanced dua2band networ% is successfu# the handoverfrom '$ ce to >$ ce is not aowed within H+!"ALTT#/"

&fter the handover fais# different penaties are performed on the tar!et ce based on the causes?

)f the handover to a nei!hborin! 1G or 4G ce fais# the actua 7 eve of the tar!et ce issubtracted by 5A#L$#$T!"#$Hfor nei!hborin! ce ran%in! durin! the penaty"

Based on the handover faiure cause# the penaty time coud be /!"ALTT#/# $C!"ALTT#/# or!"ALTT#/"

)f the >$ subce to '$ subce handover within a concentric ce fais# the handover from >$ subceto '$ subce is not aowed within T#/+T+5A#L!""

)f the '$ subce to >$ subce handover within a concentric ce fais# the handover from '$ subceto >$ subce is not aowed within T#/T++5A#L!""

-asic aning

Basic ran%in! is performed after handover penaty to !enerate a candidate ce ist in descendin! orderta%in! the foowin! information into account? 7 eves of the servin! ce and nei!hborin! ces carried

in the M7s# hysteresis# usa!e of TCHs in the nei!hborin! ces# and so on"


Copyri!ht 6 Huawei


4


18/136

4 Technica Description

GSM BSS

Handover

)n the case of non2directed retry# if an MS in an e+terna BSC ce occupies an SDCCH and#"-$C$&H+"is set to "o# then this ce shoud be removed from the candidate ce ist" )n otherwords# the handover to this e+terna BSC ce is prohibited"

)f a nei!hborin! 1G ce and the servin! ce are controed by the same BSC and the TCH usa!e of

the nei!hborin! ce is /..J# then the nei!hborin! ce shoud be removed from the candidate ce istthat is# the handover to this nei!hborin! ce is prohibited"

)f the downin% 7 eve of a nei!hborin! 1G ce is ower than the sum of H+C&C/#"&4!4and/#"+55$T# then the nei!hborin! ce shoud be removed from the candidate ce ist that is# thehandover to this nei!hborin! ce is prohibited"

)f the upin% 7 eve of a nei!hborin! 1G ce is ower than the sum of H+C&C/#"!!4and/#"+55$T# then the nei!hborin! ce shoud be removed from the candidate ce ist that is# thehandover to this nei!hborin! ce is prohibited"

)f a nei!hborin! 4G ce is an FDD ce# the ce is processed accordin! to 5&&!?

)f 5&&!is set to c>"0# and the -cN. of a nei!hborin! ce is ower than /#"C"+TH$# thenei!hborin! ce shoud be removed from the candidate ce ist that is# the handover to this

nei!hborin! ce is prohibited" )f 5&&!is set to $C!# and the 7SCP of a nei!hborin! ce is ower than /#"$C!TH$# thenei!hborin! ce shoud be removed from the candidate ce ist that is# the handover to thisnei!hborin! ce is prohibited"

)f a nei!hborin! 4G ce is a TDD ce and the 7SCP after penaty is ower than the /#"$C!TH$#the nei!hborin! ce shoud be removed from the candidate ce ist that is# the handover to thisnei!hborin! ce is prohibited"

Cacuate the difference between the downin% 7 eve of the nei!hborin! ces and the downin% 7eve of the servin! ce" Based on the difference# ran% the nei!hborin! ces in descendin! order"

"etwor Characteristics Ad=ustment

Networ% characteristics ad,ustment is a process in which the position of each ce in the candidate ceist is determined based on the reated networ% information" Networ% characteristics ad,ustmentprovides the fina candidate ce ist for handover decision"

The networ% characteristics ad,ustment refers to the /32bit @ueuin! for the candidate ces" Fi!ure /"/describes the format of /32bit @ueuin!"

5igure 1.1 Format of /32bit @ueuin!

17(1) 16 1% 12 11 10 ? @ 9 ) 7 6 % 2 1

: Huawei Proprietary and Confidentia

Copyri!ht 6 Huawei


)ssue ./ 01./.2.324.5


19/136

GSM BSS

Handover 4 Technica Description

7SID D$7$-Ihi!her

than)nter2ayerH>Threshod ornot

Co2MSCor not

Co2BSCor not

Current oadof thece

hi!herthanoadhandoverthreshod ornot

H>PriorityHierar

chy 3

H>PriorityHierar

chy ;

H>PriorityHierar

chy :

H>PriorityHierar

chy 4

H>PriorityHierar

chy 1

H>PriorityHierar

chy /

Servin! cepreferred

D$7$-I@ueuin

!

D$7$-I@ueuin

!

D$7$-I@ueuin

!

7SID Set to/ for anei!hborin!ce if7$-I isowerthanthreshod Khysteresis"Set to/ fortheservin! ceif7$-I isowerthanthresh

od 2hysteresis"

Set to/ inthecaseofnon2co2MSC

Set to/ inthecaseofnon2

co2BSC

Set to/ if thecurrent oadishi!herthanthethreshod"

)ndicates the HCS 0Hierarchica CeStructure5 priority" There are 3: eves intota 0: ayers with /3 eves on eachayer5"

Set to/ for anei!hborin!ce if7$-I ofthenei!hborin!ce isowerthan7$-I oftheservin! ceKhysteresis"Set to. forthe

servin! ce"

)ndicates the@ueuin! resut ofseven ces 0si+nei!hborin! ces Kone servin! ce5based on 7$-I"

&fter the basic ce @ueuin!# priority ad,ustment is performed on the candidate ces to define thecomprehensive priority of each candidate ce" The priority ad,ustment is based on the receive eve#receive @uaity# ce oad# inter2ayer handover threshod# ayer2eve difference# and whether the servin!ce and its nei!hborin! ces beon! to the same BSC# and MSC# &fter the priority ad,ustment# the ce@ueuin! is performed a!ain"

)n the /32bit @ueuin!# bit / 0$SB5 has the owest wei!ht and bit /3 0MSB5 has the hi!hest wei!ht" The

vaue of the /3 bits indicates the ce priority" & ow vaue of the /3 bits indicates a hi!h ce priority" &


Copyri!ht 6 Huawei


;


20/136


GSM BSS

Handover

ce with a hi!her priority is more i%ey to be seected as the tar!et ce in a handover"

/" Bits /L4? )ndicate the priority of the D$ receive eve 0on the TCH or BCCH5 of a ce" The priority isbased on the @ueue arran!ed by in the basic @ueuin!" & hi!h vaue of indicates a sma vaue

of bits /L4# which means a hi!h priority" The vaue of the servin! ce is ."

For a nei!hborin! 1G ce# BCCH si!na eve of the nei!hbor ce after fiterin! O TCH si!naeve of the nei!hborin! ce after fiterin! O )&S" For a BSC interna nei!hborin! ce# )&S -#A$ For a BSC e+terna nei!hborin! ce# )&S ."

For a nei!hborin! 4G ce# distin!uish between -cNo and 7SCP in the M7 first if the 7SCPvaue is used# then actua measurement vaue is the nei!hborin! ce ori!ina measurement vauein the nei!hborin! ce O$C!+55 if the -cNo vaue is used# then actua measurement vaue inthe nei!hborin! ce ori!ina measurement vaue in the nei!hborin! ce OC"++55" 'pdate thepriority eves of the nei!hborin! 4G ces based on the measurement vaue"

1" Bit :? Set to . permanenty for the servin! ce in handover a!orithm )" )t is set to . for thenei!hborin! ce if the foowin! formua is appied" >therwise# bit : is set to / for the nei!hborin! ce"

SSif 2 0Hi23:5 SSD$sf

)n this formua#

SSifindicates the BCCH receive eve in nei!hborin! ce i after fiterin!"

Hiindicates #"TCLLH$T, the hysteresis confi!ured for nei!hborin! ce i"

SSD$sfindicates the receive eve of the downin% TCH in the servin! ce after fiterin!"

)n handover a!orithm ))# the vaue of bit : is SS if 2 SSD$sf 2 0Hi23:5"

4" Bits ;L/.? )ndicate the ayer attribute and eve attribute of a ce" Bits =L/. indicate ayer attributeand bits ;L8 indicate eve attribute" The mappin! formua is as foows?

Payereve PayerQ/3K Peve)n this formua#

Payereveindicates the comprehensive priority on the ayer and eve basis after the mappin!" The

correspondin! bits are bits ;L/. with the vaue ran!e . to 34"

Payerindicates CLLLA"

Peveindicates !#+"

:" Bit //? )ndicates the ce oad wei!htin!" )f the system oad is hi!her than $$5L+4L:# or if$$5L+4L: is disabed# then bit // is set to the defaut vaue" The formua is different for theservin! ce and nei!hborin! ce"

Servin! ce? Set to . if the foowin! formua is appied" >therwise# bit // is set to/"

$sR Ts

)n this formua#

$sindicates the current oad of the servin! ce"

Tsindicates T#TH$ of the servin! ce"

Nei!hborin! ce? Set to . if the foowin! formua is appied" >therwise# bit // is set to /"

3 Huawei Proprietary and Confidentia

Copyri!ht 6 Huawei


)ssue ./ 01./.2.324.5


21/136

GSM BSS


$iRTi

)n this formua#

$iindicates the current oad of nei!hborin! ce i"

Ti indicates LoadAccThres"

;" Bit /1? )f C+-$C/$CA&B" is set to$# bit /1 indicates the hi!h priority of the nei!hborin! cesthat share the BSC with the servin! ce" Bit /1 is set to . for the nei!hborin! ces that share the BSCwith the servin! ce"

3" Bit /4? )f C+-$C/$CA&B" is set to$# bit /4 indicates the hi!h priority of the nei!hborin! cesthat share the MSC with the servin! ce" Bit /4 is set to . for the nei!hborin! ces that share theMSC with the servin! ce"

therwise# bit /: is set to /"

SSifTayerK HayerO 3:

)n this formua#

SSif indicates the receive eve on the BCCH of the nei!hborin! ce after fiterin!"

Tayerindicates H+TH$ of the nei!hborin! ce

Hayerindicates #"TL:H+H$T of the nei!hborin! ce

)f bit /: is set to / 0for either servin! ce or nei!hborin! ce5# then bits ;L/4 are set to ." That is# thefactors such as hierarchy# oad# and CoBSCCoMSC are not considered if bit /: is set to /" )n thiscase# ony the D$ receive eve and hysteresis are considered"

8" Bits /;L/3? 7eserved"

&fter the networ% characteristics ad,ustment# the fina candidate ce ist 0incudin! nei!hborin! ces andservin! ce5 is !enerated" The candidate ces are ran%ed in descendin! order by priority" Then# thehandover decision procedure starts"

)n handover a!orithm ))# the emer!ency handover decision is made after the networ% characteristicsad,ustment"

&fter the emer!ency handover decision# L+A&H+!":ALis subtracted from the eve of theori!ina ce within L+A&H+!"T#/if the oad handover is successfu" The eve of the tar!et cechan!es after the penaty of oad handover then# the networ% characteristics needs to be read,usted"

)n handover a!orithm )# a reated factors are ad,usted in networ% characteristics ad,ustment phase inhandover a!orithm ))# some of the factors are ad,usted before the emer!ency handover decisionprocedure is initiated"


Copyri!ht 6 Huawei



22/136


GSM BSS

Handover

5orced Handover '-5&(110)09 &irect etry*

)f the forced handover is tri!!ered# the subse@uent handover decisions are not performed"

The purpose of the forced handover is as foows?

)f no TCH is avaiabe in the servin! ce durin! the MS access process# the directed retry procedureis performed when CT"is set toes"

hen BTS maintenance is performed# the MSs under contro of the reated BTS shoud be handedover to the ces controed by a functiona BTS to ensure that no ca drop occurs durin! BTSmaintenance"

The forced handover is cassified into these four types?

>ut!oin! ce handover 0direct retry5

>ut!oin! BTS handover

>ut!oin! BSC handover

Specified tar!et ce ist handover

%.% Handover &ecision -ased on Handover Algorithm #

This section describes the feature GBFD2//.3./ H'&-) ) Handover"

&ccordin! to the emer!ency condition of an MS in the networ%# the handover decision based onhandover a!orithm ) is made in the foowin! order? @uic% handover# emer!ency handover# enhanceddua2band networ% handover# oad handover# and norma handover"

Handover decision based on handover a!orithm ) invoves the foowin! procedures?

Determinin! whether the servin! ce meets the tri!!erin! conditions

Seectin! correspondin! candidate ces

)n handover a!orithm )# H++!T$Lspecifies whether a nei!hborin! 1G ce or a nei!hborin! 4G ceis preferred"

hen H++!T$Lis set to !re3erence 3or 2 Cell?

& nei!hborin! 1G ce is preferred" )f the candidate ce ist contains suitabe nei!hborin! 4G ces butno suitabe nei!hborin! 1G ces# a nei!hborin! 4G ce is seected"

hen H++!T$Lis set to !re3erence 3or % Cell?

& nei!hborin! 4G ce is preferred" )f the candidate ce ist contains suitabe nei!hborin! 1G ces butno suitabe nei!hborin! 4G ces# a nei!hborin! 1G ce is seected"


)f the 7 eve of a candidate 1G ce is ower than or e@ua to H+!TH2# a nei!hborin! 4G ce ispreferred"

)f the tri!!erin! conditions of emer!ency handover are met and there is at east one candidate ce# thenthe emer!ency handover timer "4H+/#"#"T:is started" &nother emer!ency handoverdecision can be performed ony when "4H+/#"#"T:times out"

%.%.1 ;uic Handover

This section describes the feature GBFD2;/./.4 Chain Ce Handover"

9uic% handover aims to increase the handover success rate of an MS movin! at a hi!h speed and to

ensure the ca continuity and ow ca drop rate" 9uic% handover appies to the scenario where an MSmoves fast aon! an urban bac%bone road# a seected route# or a hi!h2speed rairoad"


Copyri!ht 6 Huawei


)ssue ./ 01./.2.324.5


23/136

GSM BSS


;uic Handover Types

9uic% handover consists of fre@uency offset handover and @uic% PBGT handover"

Fre@uency offset handover

hether the MS is movin! away from the servin! ce is determined based on the fre@uency offsetinformation provided by an MS movin! at a hi!h speed" Fre@uency offset handover decision is madeaccordin! to the upin%downin% 7 eve of the servin! ce and the path oss of nei!hborin! ces"

9uic% PBGT handover

9uic% PBGT handover decision is made accordin! to the path oss of nei!hborin! ces"

For @uic% handover# the handover response speed is enhanced by?

&ccuratey cacuatin! the movin! speed of the MS

Derestrictin! the interva between handover decisions

7educin! the number of measurement reports for the handover decision

)ntroducin! the apha fiterin!

;uic Handover !reparation

The preparation for @uic% handover invoves the foowin! aspects?

Fre@uency offset is decoded from the measurement report"

Fre@uency offset of the MS is obtained from the upin% measurement report that the BTS sends to theBSC"

&pha fiterin! is performed on the measurement report"

Triggering Conditions

Durin! handover decision# it is first determined whether the tri!!erin! conditions of fre@uency offsethandover are met" hen the BTS cannot send the fre@uency offset information or the reportedfre@uency offset information is invaid# @uic% PBGT handover is tri!!ered# provided that other conditionsof fre@uency offset handover are met"

)f ;#CH+"is set toes# the tri!!erin! conditions of @uic% handover are as foows?

The MS is movin! away from the servin! ce 0the fre@uency offset in the measurement resut is ane!ative vaue5 and the movin! speed of the MS is !reater than /+:$!&TH$"

The fitered upin% eve of the servin! ce is ower than H+!T#"

The compensated downin% eve of the servin! ce is ower than H+&+4"T#"

The path oss of confi!ured chain nei!hborin! ces is ower than the specified threshod of the path

oss of the servin! ce" )n other words# PBGT0n5 is !reater than or e@ua to ."

The tri!!erin! conditions of @uic% handover are as foows?

)f the ast three conditions are met simutaneousy# the decision is made as foows?

)f the first condition is met# a fre@uency offset handover is performed"

)f the first condition is not met# a @uic% PBGT handover is performed"

)f a the ast three conditions are not met# @uic% handover is not tri!!ered"

Target Cell $election

The tar!et ce must be a chain nei!hborin! ce of the servin! ce" The tar!et ce can be obtained

throu!h the settin! of #$CHA#""CLL" )f H++CA$T"is set to es# a nei!hborin! ce in themovin! direction of the MS is seected preferentiay"


Copyri!ht 6 Huawei


=


24/136


GSM BSS

Handover

To forecast the movin! direction of the MS# the direction of a chain nei!hborin! ce 0& or B5 comparedwith the servin! ce is specified by CHA#""CLLT!" )f the number of times that the MS is handedover to nei!hborin! ces in the same direction 0B for e+ampe5 is !reater than or e@ua toH+LA$TT#/when the handover time reaches H+$TAT#/# then the MS is inferred to bemovin! towards the B direction" Subse@uenty# the MS is preferentiay handed over to the nei!hborin!ce whose CHA#""CLLT!is B"

Limitations

The imitations on @uic% handover are as foows?

The servin! ce cannot be seected as the tar!et ce"

The candidate ces for @uic% handover must be chain nei!hborin! ces of the servin! ce" -ach cecan be confi!ured with a ma+imum of three chain nei!hborin! ces"

&fter a @uic% handover is successfu# the penaty is performed on the ori!ina ce durin! the penatytime to prevent an immediate handover bac% to the ori!ina ce" The penaty time and penaty vaueare specified by T#/!"#$Hand H+!"#$H:ALrespectivey"

%.%.2 TA Handover

T& handover is a type of emer!ency handover" The T& handover decision is made accordin! to the T&vaue reported by the MS"

The T& vaue of a norma ce ran!es from . to 34 and that of an e+tended ce ran!es from . to 11="The T& can be stepped up or down in steps of ;;4"; m" The T& vaue of 34 corresponds to a distance of4; %m"


T& handover is tri!!ered when the foowin! conditions are met?

TAH+"is set toes"

Fitered T& vaue in the measurement report provided by the MS is !reater than or e@ua to TAL#/#T"

The T& handover can be tri!!ered ony when the precedin! two conditions are met simutaneousy"

From the perspective of the tri!!erin! conditions of T& handover# T& can be re!arded as a imitation to the siAe of a ce"


The tar!et ce shoud have the hi!hest priority in the candidate ce ist after handover preprocessin!" )naddition# the tar!et ce shoud meet the foowin! conditions?


)f TAL#/#Tof a co2site nei!hborin! ce is ower than or e@ua to the TAL#/#Tof the servin! ce# ahandover to the nei!hborin! ce is prohibited"

)f the tri!!erin! conditions of T& handover are met but the candidate 1G ces are not suitabe# thefoowin! operations are performed?

)f a nei!hborin! 4G ce is avaiabe# if #"TAT+T-$CH+"is set toes# and if the MSsupports the 1G4G inter27&T handover# the 1G4G inter27&T handover is performed"

)f no nei!hborin! 4G ce is avaiabe# if #"TAT+T-$CH+"is set to "o# or if the MS does notsupport the 1G4G inter27&T handover# the decision on whether to initiate another type of emer!encyhandover is made"

/. Huawei Proprietary and Confidentia

Copyri!ht 6 Huawei


)ssue ./ 01./.2.324.5


25/136

GSM BSS


Limitations

&fter the T& handover is successfu# the penaty is performed on the ori!ina ce" Durin!T#/TA!"#$H# $$TA!"#$His subtracted from the eve of the ori!ina ce to prevent an immediatehandover bac% to the ori!ina ce"

%.%.% -; Handover

B9 handover is a type of emer!ency handover in which the system ma%es the decision based on theupin%downin% 7 @uaity on the 'm interface"

The 7 @uaity is measured in bit error rate 0B-75" The BSC measures the @uaity of a radio in% basedon the @uaity cass in the measurement report" The probabe cause of an increase in B-7 is that thesi!na power is too ow or the channe interference increases"


)f -;H+"is set toes# the tri!!erin! conditions of B9 handover are as foows?

The upin% 7 @uaity is !reater than or e@ua to the upin% 7 @uaity threshod of the servin! ce"

The downin% 7 @uaity is !reater than or e@ua to the downin% 7 @uaity threshod of the servin!ce"

The B9 handover is tri!!ered when either of the precedin! conditions is met"

The parameters for specifyin! the upin% and downin% 7 @uaity threshods are as foows?

For non2&M7 cas# the parameter for specifyin! the upin% 7 @uaity threshod is L;AL#/#Tandthe parameter for specifyin! the downin% 7 @uaity threshod is &L;AL#/#T"

For &M7 F7 cas# the parameter for specifyin! the upin% 7 @uaity threshod isL;AL#/#TA/5and the parameter for specifyin! the downin% 7 @uaity threshod is

&L;AL#/#TA/5"

For &M7 H7 cas# the parameter for specifyin! the upin% 7 @uaity threshod isL;AL#/#TA/Hand the parameter for specifyin! the downin% 7 @uaity threshod is&L;AL#/#TA/H"



)f the tar!et ce is a nei!hborin! ce# the 7 eve of the tar!et ce must meet the foowin! condition?

Fitered downin% 7 eve of the tar!et ce Fitered downin% 7 eve of the servin! ce K

0#"TCLLH$Tof the servin! ce confi!ured for the nei!hborin! ce 2 3:5 2 0-;/A#" 3:5

)n handover a!orithm )# if there is ony one ce in the candidate ce ist and the ce is a nei!hborin! ce# then theprecedin! condition need not be met"

)n handover a!orithm )# if there is no nei!hborin! ce# #"TACLLH+"is set toes# and theservin! ce is not in the intra2ce handover penaty state# then the MS is handed over to the servin!ce" & channe with different fre@uency band# different fre@uency# different T7# or different timesot ispreferred 0priority? different fre@uency band different fre@uency different T7 different timesot5"

)f the tri!!erin! conditions of B9 handover are met but the candidate 1G ces are not suitabe# thefoowin! operations are performed?



Copyri!ht 6 Huawei


//


26/136


GSM BSS

Handover


Limitations

&fter the B9 handover is successfu# the penaty is performed on the ori!ina ce" Durin!T#/-;!"#$H# $$-;!"#$His subtracted from the eve of the ori!ina ce to prevent animmediate handover bac% to the ori!ina ce"

%.%.6 apid Level &rop Handover

7apid eve drop handover is a type of emer!ency handover"

)n ed!e handover and PBGT handover# the mean vaue fiterin! and PN decision methods are notresponsive to short2period rapid eve drop" Therefore# to sove the rapid eve drop probem# the finiteimpact response fiterin! can be performed on the ori!ina 7 eve" This fiterin! method is responsiveto the rapid eve drop based on the drop sope of the ori!ina 7 eve"


)f L&TH$is set toes# the tri!!erin! conditions of rapid eve drop handover are as foows?

Fitered upin% eve R L&TH$

&/ + C0nt5 K &1 + C0nt 2 t5 K &4 + C0nt 2 1t5 K U K &8 + C0nt 2


27/136

GSM BSS



)f #"T5H+"is set toes# the tri!!erin! conditions of interference handover are as foows?

The fitered vaue of upin% 7 @uaity is !reater than or e@ua to the specified 7 @uaity threshod at

the current upin% 7 eve"The fitered vaue of downin% 7 @uaity is !reater than or e@ua to the specified 7 @uaity threshod

at the current downin% 7 eve"

The interference handover is tri!!ered if either of the previous conditions is met"


For non2&M7 F7 cas# the parameter for specifyin! the 7 @uaity threshod is ;ALn# where / Vn V /1"

For &M7 F7 cas# the parameters for specifyin! the 7 @uaity threshod are ;ALn0/ V n V /15and L:+55"

)f n /# the 7 @uaity threshod is ;AL1" )f 1 V n V /1# the 7 @uaity threshod is ;ALnK L:+55"


)n handover a!orithm )# the tar!et ce shoud have the hi!hest priority in the candidate ce ist" )naddition# the tar!et ce shoud meet the foowin! conditions?

)f #"TACLLH+"is set toesand the intra2ce handover penaty timer e+pires# the servin! cecan be seected as the tar!et ce"

hen a number of consecutive intra2ce handovers occur# -A"T#/is tri!!ered and the intra2ce handover isprohibited in the correspondin! period"

)f the fitered eve of a nei!hborin! ce after handover penaty H+TH$of the nei!hborin! ce K#"TL:H+H$T2 3:# this nei!hborin! ce can serve as the tar!et ce"

)f the tri!!erin! conditions of interference handover are met but the candidate 1G ces are not suitabe#the foowin! operations need to be performed?

)f a nei!hborin! 4G ce is avaiabe# #"TAT+T-$CH+"is set toes# and the MS supportsthe 1G4G inter27&T handover# the 1G4G inter27&T handover is performed"

)f no nei!hborin! 4G ce is avaiabe# #"TAT+T-$CH+"is set to "o# or the MS does notsupport the 1G4G inter27&T handover# the decision on whether to initiate another type of emer!encyhandover is made"

%.%.) Handover &ue to "o &ownlin /easurement eportHandover due to no downin% measurement report is performed on the basis of the upin% @uaity" Thepurpose is to ensure the ca continuity and minimiAe the possibiity of ca drops"

Handover due to no downin% measurement report is !eneray caused by adverse radio environmenton the upin%" )n this case# the re@uirements of the fiterin! a!orithm cannot be met# so other handoverdecisions cannot be performed"


)n handover a!orithm )# the tri!!erin! conditions of handover due to no downin% measurement reportare as foows?

"+&L/H+"is set toes"


Copyri!ht 6 Huawei


/4


28/136


GSM BSS

Handover

There is no downin% information in the measurement report of the ca"

The fitered vaue of upin% @uaity is !reater than or e@ua to "+&L/H+;ALL#/#T"

The number of ost downin% M7s is smaer than "+&L/H+ALL+4L#/#T"

For TCH# the number of saved M7s with upin% @uaity vaue is !reater than &ATA;A5LTL" for

SDCCH# the number of saved M7s with upin% @uaity vaue is !reater than ;L"$#"

hen a the previous conditions are met# the handover due to no downin% measurement report istri!!ered"


)n handover a!orithm )# the conditions for seectin! the tar!et ce are as foows?

The ran%ed nei!hborin! ces recorded in the ast compete measurement report are saved ascandidate ces"

Preferaby a nei!hborin! ce is seected as the tar!et ce"

)f no nei!hborin! ce is avaiabe# the servin! ce is seected as the tar!et ce"

%.%.9 nhanced &ual(-and "etwor Handover

-nhanced dua2band networ% handover is performed based on the traffic voume of the overaid andunderaid ces and based on the receive eve"

-nhanced dua2band networ% handover is cassified into the foowin! types?

Handover due to hi!h oad in the underaid ce

Handover due to ow oad in the underaid ce

Handover due to MS movement to the border of the overaid ce

Triggering Conditions o3 Handover &ue to High Load in the nderlaid Cell

The tri!!erin! conditions of the handover due to hi!h oad in the underaid ce are as foows?

The two ces are in the enhanced dua2band networ% and +TL+A&H+"A-Lis set toes"

The MS supports the fre@uency band on which the overaid ce operates"

The handover due to hi!h oad in the underaid ce is performed ony on TCHs"

The oad in the underaid ce is hi!her than or e@ua to +T"+:L&TH&"

The oad in the overaid ce is ower than #""$#+:L&TH&"

The system traffic voume is ower than or e@ua to &-$$5L+4L:"

The current ca is within the handover mar!in and the receive eve is !reater than or e@ua to

#"T+#""L:TH&"

hen a the precedin! conditions are met# the handover due to hi!h oad in the underaid ce istri!!ered"

)f the oad of the underaid subce in the ce is hi!her than or e@ua to +T$#+:L&TH thenthe handover mar!in is ad,usted in a period of +TL+A&H+!#+&subtracted by+TL+A&H+/+&!#" The step en!th for handover mar!in ad,ustment is specified by+TL+A&H+$T!"

Triggering Conditions o3 Handover &ue to Low Load in the nderlaid Cell

The tri!!erin! conditions of the handover due to ow oad in the underaid ce are as foows?

The oad in the underaid ce is ower than +TL+4L+A&TH&"

/: Huawei Proprietary and Confidentia

Copyri!ht 6 Huawei


)ssue ./ 01./.2.324.5


29/136

GSM BSS



The current ca is within the handover mar!in and the receive eve is !reater than or e@ua to+T#""L:TH&"

hen a the precedin! conditions are met# the handover due to ow oad in the underaid ce is

tri!!ered"

)f the oad of the underaid subce is ower than +TL+4L+A&TH&for a specified period# then thehandover mar!in is ad,usted in a period of #""L+A&H+!#" The step en!th for handover mar!inad,ustment is specified by #""L+A&H+$T!"

Triggering Conditions o3 Handover &ue to /$ /ovement to the -order o3 the+verlaid Cell

The tri!!erin! conditions of the handover due to MS movement to the border of the overaid ce are asfoows?

SS0s5 R Thdouter

SS0u5 2 SS0n5 R &TCBTH7D 2 &TCBHST

Here#

SS0s5? specifies the fiterin! compensated downin% 7 eve in the servin! ce"

Thdouter? specifies +T#""L:TH&"

SS0u5? specifies the downin% eve 0power compensation is performed on the downin% eve basedon the measurement5 of the underaid ce where the ca is ori!inated" )f the SS0u5 vaue cannot beobtained# you can infer that the decision of enhanced dua2band networ% handover is not performedand the decision condition is met by defaut"

SS0n5? The best nei!hborin! ce is the one whose measured BCCH eve is the hi!hest amon!nei!hborin! ces" SS0n5 is the si!na eve of the best nei!hborin! ce that operates on the same

fre@uency band# ocates at the same ayer# and has the same priority as the underaid ce but is notco2sited with the underaid ce" )f such a nei!hborin! ce is not avaiabe# the vaue of SS0n5 is 2//.dBm"

&TCBTH7D? specifies ATC-TH&"

&TCBHST? specifies ATC-H$T"

Handover due to MS movement to the border of the overaid ce is tri!!ered if either of the precedin!conditions is met"

)n the adapter distance to ce border0&TCB5 handover a!orithm# the border between the overaid and underaid cesis determined accordin! to the si!na stren!th of the servin! ce and that of nei!hborin! ces" )f SS0s5 SS0n5# thesystem considers that the MS is ocated at the border of the underaid ce" )f SS0s5 2 SS0n5 &TCBTH7D# the system

considers that the MS is ocated in the covera!e area of the overaid ce" The covera!e area of the overaid ce isdetermined accordin! to different networ%in! and covera!e conditions of the e+istin! networ%" )n addition# the overaidce of the servin! ces and the overaid ce of the nei!hborin! ces wi not overap re!ardess of the distancebetween BTSs"

The handover mar!in specifies the ran!e of si!na eve" )n the case of overaidunderaid oad handover on theenhanced dua2band networ%# the MSs whose downin% eves are within the handover mar!in are handed over eveby eve"


The re@uirements for tar!et ce seection in the enhanced dua2band networ% are as foows?

For the handover due to hi!h oad in the underaid ce# the MS must be handed over to the overaidce"

For the handover due to ow oad in the underaid ce# the MS must be handed over to the underaid


Copyri!ht 6 Huawei


/;


30/136


GSM BSS

Handover

ce"

For the handover due to MS movement to the border of the overaid ce# the MS is handed over tothe nei!hborin! ce that ran%s first amon! nei!hborin! ces" The MS shoud not be handed over tothe ce that ran%s after the servin! ce" Generay# the tar!et ce is the underaid ce" The tar!et ce

can aso be another nei!hborin! ce"

Limitations

The imitations on the handover due to hi!h oad in the underaid ce are as foows?

)f the ce where the ca is ocated is on an enhanced dua2band networ%# CLL#"T!is set to8tra'8tra*"

The +TL+A&H+"A-Lparameter shoud be set"

The ma+imum ran!e of the handover mar!in is from 34 to #"T+#""L:TH&" The MS withthe hi!hest receive eve is handed over first"

The imitations on the handover due to ow oad in the underaid ce are as foows?

)f the ce where the ca is ocated is on the enhanced dua2band networ%# CLL#"T!is set to#nner'#nner*"

The #""L+A&H+"parameter shoud be set"

The ma+imum ran!e of the handover mar!in is from 34 to +T#""L:TH&" The MS with theowest receive eve is handed over first"

The imitations on the handover due to MS movement to the border of the overaid ce are as foows?


#mpact o3 the nhanced &ual(-and "etwor Handover on the 8isting

Algorithm

The impact of the enhanced dua2band networ% handover on the e+istin! a!orithm is as foows?

>n the enhanced dua2band networ%# the MS shoud not be handed over to a ce in the sameunderaidoveraid ce !roup when the oad handovers between the overaid ce and the underaidce 0specified by +TL+A&H+"A-Land #""L+A&H+"5 are aowed" This is to prevent a oadhandover of a norma ce from coidin! with a oad handover between the overaid ce and theunderaid ce on the networ%"

The PBGT handover a!orithm may cause inter2ce handover thus# the MS shoud not be handedover to the ce in the same !roup in the case of PBGT handover between ces on the enhanceddua2band networ%"

%.%.@ Load Handover

)n the networ%# some ces carry heavy oad whereas the overappin! upper2ayer ces and thenei!hborin! ces may carry i!ht oad" To baance the oad of these ces# the oad handover is re@uired"

)n a oad handover procedure# some oad in heavy2oad ces is switched to i!ht2oad ces" Meanwhie#the oad in nei!hborin! ces is not switched to heavy2oad ces"

$oad handover can be performed between ces at different ayers" Fi!ure 42/shows the detais"

For detais about the inter27&T oad handover# see the 1G4G )nteroperabiity Parameter Description feature"

/3 Huawei Proprietary and Confidentia

Copyri!ht 6 Huawei


)ssue ./ 01./.2.324.5


31/136

GSM BSS


5igure 1.1 $oad handover between ces

& ce with

a heavy oad

& ce witha heavy oad

& ce with

a heavy oad

& ce witha i!ht oad

& ce with

a i!ht oad

& ce with

a i!ht oad

& ce witha i!ht oad

To perform oad sharin!# increase &L&TH$so that the oad at the border of a ce is switched to

a nei!hborin! ce with i!ht oad"

hether a ce carries heavy oad or i!ht oad is determined by the traffic voume in the ce# that iswhether the traffic voume 0!eneray TCH usa!e5 in the ce e+ceeds the preset threshod"

)f the traffic voume in a ce is !reater than T#TH$# you can infer that the oad in this ce isheavy" The oad handover a!orithm needs to be enabed"

)f the traffic voume in a ce is ower than LoadAccThres# you can infer that the oad in this ce isi!ht and the ce can receive oad from the heavy2oad ces"

$oad handover may ead to many handovers" Therefore# the oad of the system CP' shoud beconsidered before oad handover is performed" )n other words# the system traffic voume shoud beta%en into account" )n addition# to prevent too many MSs from bein! handed over at a time# oad

handover is performed step by step" )n other words# the ed!e handover threshod is increased on thebasis of L+A&H+$T!0C$S7amp5 and L+A&H+!#+&0C$SPeriod5" hen the increase in theed!e handover threshod e@uas L+A&+55$T0C$S>ffset5# the ed!e handover threshod is notincreased any more" See Fi!ure 421for detais"

5igure 1.2 $oad handover

C>NFH>7$-I

C>NFH>7$-IKC$S7amp

C>NFH>7$-IKC$S>ffset

Ce & Ce B

Border of norma handover$oad handover band


)f LoadHonis set toes# the tri!!erin! conditions of oad handover are as foows?

The CP' usa!e of the system is ess than or e@ua to $$5L+4L:"


Copyri!ht 6 Huawei


/


32/136


GSM BSS

Handover

The current oad of the servin! ce is !reater than or e@ua to T#TH$"


The conditions for seectin! the tar!et ce are as foows?

Fitered 7 eve after handover penaty H+TH$K #"TL:H+H$T2 3:


)f the tar!et ce and the servin! ce are in the same BSC# a oad handover is performed when thecurrent oad of the tar!et ce is ower than LoadAccThres"

)f the tar!et ce and the servin! ce are not in the same BSC# a oad handover is performed when theoad of the tar!et ce is ower than LoadAccThresand +ut-scLoadHonis set toes"

8amples

The system assi!ns MSs to different oad handover mar!ins based on the downin% 7 eve" The oadhandover a!orithm is used to hand over the MSs out of a ce step by step"

1" The MSs in oad handover mar!in / are handed over to the nei!hborin! ces" $oad handovermar!in / specifies the area where the downin% eve ran!es from &L&TH$to the sum of&L&TH$and L+A&H+$T!"

4" &fter a L+A&H+!#+&eapses# the MSs in oad handover mar!in 1 are handed over to thenei!hborin! ces" The oad handover mar!in 1 specifies the area where the downin% eve ran!esfrom &L&TH$to the sum of &L&TH$and 01 + L+A&H+$T!5"

:" The oad handover stops when the traffic voume in the ce is ess than or e@ua to T#TH$"

The oad handover is performed step by step to prevent ca drops caused by a sudden increase in CP'oad or the con!estion in the tar!et ce"

%.%.? nhanced Load HandoverLike the load handover, the enhanced load handover is used to balance load of cells in a network. Unlike the load

handover, the enhanced load handover considers the handover quality and the load in the target cell before the

handover is performed. n this way, the possibility of low level and congestion due to heavy load in the target cell

after the handover is minimi!ed. "he enhanced load handover is applicable to the scenario where multiple basestations are located at the same place.

/8 Huawei Proprietary and Confidentia

Copyri!ht 6 Huawei


)ssue ./ 01./.2.324.5


33/136

GSM BSS


Triggering Conditions o3 nhanced Load Handover

)f L+A&H+A&is set to$# the tri!!erin! conditions of an enhanced oad handover are as foows?

The CP' usa!e of the current system is ower than or e@ua to $$5L+4L:"

The oad of the servin! ce is hi!her than T#TH$"

Here# the oad of the servin! ce is e+pressed in the percenta!e of the channes that are occupied" )f

the buit2in PC' is used# the cacuation method of the ce oad depends on the settin! of

L+A&$TAT!" The settin! of the parameter determines whether the dynamic PDCHs that can be

preempted are considered as occupied channes"

hen L+A&$TAT!is set to0, the dynamic PDCHs that can be preempted are not considered in

the ce oad"

hen L+A&$TAT!is set to1, the dynamic PDCHs that can be preempted are considered as

occupied TCHs in the ce oad"

hen L+A&$TAT!is set to2, the dynamic PDCHs that can be preempted are considered as

ide TCHs in the ce oad"

The number of the dynamic PDCHs that can be preempted depends on the number of dynamic PDCHsand&"CH"!/!TL:" The number of dynamic PDCHs is the tota number of channes whoseCHT!is set to 5LLTCH"

)f the e+terna PC' is used# the number of the dynamic PDCHs that can be preempted is aways Aero"The settin! of L+A&$TAT! is thus irreevant to cacuation of the ce oad"


hen a candidate ce satisfyin! the foowin! conditions is found and not a sin!e MS within the ran!especified by L+A&H+$AT#+is handed over to the tar!et ce# further search of the tar!et ce isstopped and current traffic is handed over to the candidate ce" The detaied conditions for seectin! thetar!et ce are as foows?

The vaue of L+A&H+!-T/A#"is not 0and the path oss in the servin! ce minus that in the

tar!et ce is ar!er than L+A&H+!-T/A#""

The oad of the tar!et ce is ower than LoadAccThres"

The receive eve of the tar!et ce is hi!her than H+TH$ of the tar!et ce pus

#"TL:H+H$Tof the handover from the servin! ce to the tar!et ce"

>f a the MSs that are within the ran!e specified by L+A&H+$AT#+and meet the precedin!conditions# ony one MS can initiate the handover at a time" This re!uation prevents too many MSsfrom bein! handed over to the tar!et ce at one time and thus avoids con!estion in the tar!et ce"

%.%.10 dge Handover

-d!e handover is performed on the basis of receive eve"

To tri!!er an ed!e handover# the receive eve of the tar!et ce shoud be at east one hysteresis vaue0specified by #"TCLLH$T2 3:5 !reater than the receive eve of the servin! ce"


Copyri!ht 6 Huawei


/=


34/136


GSM BSS

Handover


)f 5#"H+"is set toes# the tri!!erin! conditions of ed!e handover are as foows?

-ither of the foowin! conditions is met"

The fitered downin% 7 eve of the servin! ce is ower than &L&TH$"

The fitered upin% 7 eve of the servin! ce is ower than L&TH$"

7 eve of the nei!hborin! ce 7 eve of the servin! ce K #"TCLLH$T 3:

&n ed!e handover is tri!!ered when the PN criterion is met# that is# when the previous conditions aremet for &LA$T1within &$TAT1"

Fi!ure 424shows the ed!e handover"

5igure 1.1 -d!e handover

Ce 1Ce /

2=< dBm 28; dBm


The tar!et ce shoud have the hi!hest priority amon! the candidate ces" )n addition# it shoud meet

the foowin! conditions?


&fter ces are ran%ed# the tar!et ce must have a hi!her priority than the servin! ce"

& ce becomes the tar!et ce if the previous conditions are met for &A&BLA$TT#/within&A&B$TATT#/"

)f the tri!!erin! conditions of ed!e handover are met but the candidate 1G ces are not suitabe# thefoowin! operations are performed?


)f no nei!hborin! 4G ce is avaiabe# if #"TAT+T-$CH+"is set to "o# or if the MS does notsupport the 1G4G inter27&T handover# the decision on whether to initiate another type of handover ismade"

%.%.11 5ast(/oving /icro Cell Handover

Fast2movin! micro ce handover is performed from a micro ce to a macro ce accordin! to the reativespeed of an MS so that the number of handovers can be minimiAed"

Fast2movin! micro ce handover appies to the foowin! scenarios?

)f an MS is movin! fast in a micro ce# it is handed over to a macro ce"

To prevent an MS that is movin! fast in a macro ce from enterin! a micro ce# time penaty isperformed on the micro ce so that the fast2movin! MS camps on the macro ce"

1. Huawei Proprietary and Confidentia

Copyri!ht 6 Huawei


)ssue ./ 01./.2.324.5


35/136

GSM BSS


Fi!ure 42:shows the fast2movin! micro ce handover"

5igure 1.1 Fast2movin! micro ce handover

'mbrea ce

Micro ce


)f ;C/:H+"is set toes# the handover decision procedure of fast2movin! micro ce handover isas foows?

1" hen the tri!!erin! conditions of ed!e handover or PBGT handover are met# the fast2movin! microce handover decision is started"

4" hen the period durin! which the MS camps on the servin! ce is shorter than ;CT#/TH# thenumber of ces throu!h which the fast2movin! MS passes is incremented by one"

The ce counted by the system must ocate at a ayer ower than ayer :" )n other words# it must be a non2'mbrea ce":" hen the number of ces that the MS passes in fast movement reaches ;C$TATC"T# the fast2

movin! micro ce handover is tri!!ered if the number of ces that the MS passes in fast movementcounted by the system is !reater than or e@ua to ;CTC"T"


)n handover a!orithm )# the tar!et ce shoud have the hi!hest priority amon! the candidate ces" )naddition# the tar!et ce shoud meet the foowin! conditions?

The tar!et ce must be at ayer :# that is# 'mbrea ce"

Fitered 7 eve of the tar!et ce H+TH$K #"TL:H+H$T2 3:

Limitations

&fter the fast2movin! micro ce handover is successfu# the penaty is performed on a the nei!hborin!micro ces" Durin! $!&!"#$HT# $&!":ALis subtracted from the 7 eve of every nei!hborin!micro ce"

Cell Layer and Cell !riority

ith Huawei mutiband handover a!orithm# a proper traffic voume distribution can be reaiAed amon!mutipe fre@uency bands"

Huawei mutiband handover a!orithm divides ces into four ayers# with /3 priorities at each ayer" TheLAparameter specifies at which ayer a ce is ocated" This a!orithm is appicabe to compe+

networ%in! scenarios" Fi!ure 42;shows the ce ayers"


Copyri!ht 6 Huawei


1/


36/136


GSM BSS

Handover

5igure 6.1 Ce ayers

Layer 6

Layer %

Layer 2

Layer 1

/acro Cell

/icro Cell

!ico Cell

m


37/136

GSM BSS


Fitered downin% 7 eve of the tar!et ce H+TH$K #"TL:H+H$T2 3:

&fter ces are ran%ed# the tar!et ce must have a hi!her priority than the servin! ce"

The inter2ayer handover is tri!!ered when the PN criterion is met# that is# the previous conditions aremet for L:LA$Twithin L:$TAT"


The re@uirements for tar!et ce seection are as foows?

The tri!!erin! conditions are met"


The tar!et ce has the hi!hest priority in the candidate ce ist"

%.%.1% !-T Handover

This section describes the feature GBFD2;/./.1 Fast Move Handover"

PBGT handover is a type of norma handover"


)f !-TH+"is set toes# the tri!!erin! conditions of PBGT handover are as foows?

The tar!et ce and the servin! ce are at the same ayer and have the same priority"

The foowin! condition is met for !-TLA$Twithin !-T$TAT?

0M)N 0MSTP7M P5 O 7$-ID$ O P7D)FF5 O 0M)N 0MSTP7M& 0n5# P5 O7$-INC-$$ 0n5 5 PBGTH>M&7G)N

Here#

7$-ID$? indicates the fitered downin% 7 eve of the servin! ce"MSTP7M&? indicates the ma+imum aowed transmit power of an MS in the servin! ce"

MSTP7M& 0n5? indicates the ma+imum aowed transmit power of an MS in nei!hborin! cen"

7+$evNC-$$ 0n5? indicates the downin% receive eve in nei!hborin! ce n"

P7D)FF? indicates the difference between the ma+imum downin% transmit power in the servin!ce due to power contro and the actua downin% transmit power in the servin! ce"

P? indicates the ma+imum transmit power of an MS"

PBGTH>M&7G)N? indicates !-T/A#"minus 3:"

The PBGT handover can be tri!!ered ony when a the previous conditions are met"


The tar!et ce shoud meet the foowin! conditions?

The tar!et ce and the servin! ce are at the same ayer and have the same priority"


The tar!et ce has the hi!hest priority in the candidate ce ist"

%.%.16 A/ Handover

This section describes the feature GBFD2//;;.: &M7 F7H7 Dynamic &d,ustment"

The &M7 handover in handover a!orithm ) is performed on &M7 cas on the basis of radio @uaity


Copyri!ht 6 Huawei


14


38/136


GSM BSS

Handover

indication 079)5" )t consists of the &M7 TCHF2TCHH handover and the &M7 TCHH2TCHF handover"

The conversion formua between 79) and C) is 79) 1 + C)"

Triggering Conditions o3 A/ TCH5(TCHH Handover

The tri!!erin! conditions of &M7 TCHF2TCHH handover are as foows?

#"TACLL5HH+"is set to es"

The tar!et ca is an &M7 ca"

The haf2rate function must be enabed in the ce where the ca is initiated"

The fu2rate speech version 4 and haf2rate speech version 4 must be supported by the ce where theca is initiated"

The type of channe specified by the MSC durin! a ca can be chan!ed durin! a handover"

For an &M7 F7 ca# if A/TCHH!#+ALL+4is set to es and the ce oad is !reater thanA/TCHH!#+L+A the handover is aowed"

The ca occupies the fu2rate TCH" The 79) is !reater than #"H+52HTHand the ce oad is !reaterthan A/TCHH!#+L+A&"

For an &M7 F7 ca# the &M7 TCHF2TCHH handover can be performed if the precedin! conditions aremet for #"5HH+LA$Twithin #"5HH+$TAT"

Triggering Conditions o3 A/ TCHH(TCH5 Handover

The tri!!erin! conditions of &M7 TCHH2TCHF handover are as foows?

#"TACLL5HH+"is set to es"

The tar!et ca is an &M7 ca"

The haf2rate function must be enabed in the ce where the ca is initiated"

The fu2rate speech version 4 and haf2rate speech version 4 must be supported by the ce where theca is initiated"

The type of channe specified by the MSC durin! a ca can be chan!ed durin! a handover"

The ca occupies the haf2rate TCH" The 79) is smaer than #"H+H25TH"

For an &M7 H7 ca# the &M7 TCHH2TCHF handover can be performed if the precedin! conditions aremet for #"5HH+LA$Twithin #"5HH+$TAT"


The &M7 handover is an intra2ce handover" Therefore# ony the servin! ce can be seected as thetar!et ce"

%.%.17 $&CCH Handover

This section describes the feature GBFD2//.3.8 SDCCH Handover"

SDCCH handover is a process in which the MS is handed over from an SDCCH to another SDCCH inan immediate assi!nment" SDCCH handover heps improve the access success rate of the MSs on theed!e of the networ%# thus improvin! the networ% 9oS"

The principe of SDCCH handover is the same as that of TCH handover" 7e!ardin! procedure# anSDCCH handover invoves measurement and M7 reportin!# M7 processin!# handover decision# andhandover e+ecution"

hether an SDCCH handover can be performed is controed by the $#CHA"H+"parameter" )f an

1: Huawei Proprietary and Confidentia

Copyri!ht 6 Huawei


)ssue ./ 01./.2.324.5


39/136

GSM BSS


inter2BSC SDCCH handover is re@uired# both $#CHA"H+"and #"-$C$&H+"shoud be set to$'es*"

The handover decision a!orithm for SDCCH handover is different from that for TCH handover in thefoowin! ways?

The a!orithms for the foowin! handovers support SDCCH handover?

@uic% handover# T& handover# B9 handover# rapid eve drop handover# interference handover#handover due to no downin% measurement report# ed!e handover# and fast2movin! micro cehandover

The a!orithms for the foowin! handovers do not support SDCCH handover?

enhanced dua2band networ% handover# oad handover# inter2ayer handover# PBGT handover# &M7handover# better 4G ce handover# concentric ce handover# and ti!ht BCCH handover

%.%.1) +ther Handovers

>ther handovers here refer to better 4G ce handover and ti!ht BCCH handover"

-etter % Cell Handover

See 1G4G )nteroperabiity Parameter Description"

Tight -CCH Handover

See BCCH Dense Fre@uency Mutipe+in! Parameter Description"

%.6 Handover &ecision -ased on Handover Algorithm ##

This section describes the feature GBFD2;/.;./ H'&-) )) Handover"

Handover decision based on handover a!orithm )) is made in the foowin! order? forced handover#emer!ency handover# intra2ce handover# and inter2ce handover"

Handover decision based on handover a!orithm )) invoves the foowin! procedures?

Determinin! whether the servin! ce meets the tri!!erin! conditions

Seectin! correspondin! candidate ce ist for each handover type

Performin! the comprehensive decision and determinin! the candidate nei!hborin! ces

The procedure for performin! comprehensive decision based on handover resuts and determinin! thecandidate nei!hborin! ces is as foows?

/" The BSC seects a handover type with the hi!hest priority from a the handovers that can be

performed on each nei!hborin! ce"The handover priority is as foows?

Forced handover# emer!ency handover# and interference handover have a hi!h priority" Fi!ure 423shows the detais"


Copyri!ht 6 Huawei


1;


40/136


GSM BSS

Handover

5igure 1.1 Handovers with hi!h priority

Handover decision with

hi!h priority

Forced handover

Directed retry

9uic% handover

T& handover

)nterference

B9 handover

-d!e handover

9uic% handover is cassified into fre@uency offset handover and @uic% PBGT handover" Fre@uency offset handover has ahi!her priority than @uic% PBGT handover"

)ntra2ce handover 0e+cudin! interference handover5 and inter2ce handover have a norma priority"

Fi!ure 42


41/136

GSM BSS


5igure 1.2 Handovers with norma priority

Handover decision

with norma priority

Fast2movin! micro cehandover

-nhanced dua2band

networ% handover

$oad handover

Better ce handover

Concentric ce handover

&M7 handover

T)GHT BCCH handover

1" The BSC ran%s the candidate ces accordin! to the networ% characteristics ad,ustment a!orithmand then !enerates the fina candidate ce ist" -very nei!hborin! ce in the candidate ce ist hasits own handover decision" Nei!hborin! 1G ces and nei!hborin! 4G ces are ran%ed separatey"

4" )n handover a!orithm ))# H++!T$Lspecifies whether a nei!hborin! 1G or a nei!hborin! 4G ceis preferred"


& nei!hborin! 1G ce is preferred" )f the candidate ce ist contains suitabe nei!hborin! 4G cesbut no suitabe nei!hborin! 1G ces# a nei!hborin! 4G ce is seected"

hen H++!T$Lis set to !re3erence 3or % Cell?

& nei!hborin! 4G ce is preferred" )f the candidate ce ist contains suitabe nei!hborin! 1G cesbut no suitabe nei!hborin! 4G ces# a nei!hborin! 1G ce is seected"

hen H++!T$Lis set to !re3erence 3or 2 Cell -y Threshold?

)f the 7 eve of a candidate 1G ce is ower than or e@ua to H+!TH2# a nei!hborin! 4G ce

is preferred"

hen a nei!hborin! 4G ce is preferred amon! the candidate ces# the priority of 4G better ce handover is the owest"

)f the tri!!erin! conditions of emer!ency handover are met and there is at east one candidate ce# thenthe emer!ency handover timer "4H+/#"#"T:is started" &nother emer!ency handoverdecision can be performed ony when "4H+/#"#"T:times out"

%.6.1 ;uic Handover

This section describes the feature GBFD2;/./.4 Chain Ce Handover"

9uic% handover aims to increase the handover success rate of an MS movin! at a hi!h speed and toensure the ca continuity and ow ca drop rate" 9uic% handover appies to the scenario where an MS


Copyri!ht 6 Huawei


1


42/136


GSM BSS

Handover

moves fast aon! an urban bac%bone road# a seected route# or a hi!h2speed rairoad"

;uic Handover Types

9uic% handover consists of fre@uency offset handover and @uic% PBGT handover"

Fre@uency offset handover

hether the MS is movin! away from the servin! ce is determined based on the fre@uency offsetinformation provided by an MS movin! at a hi!h speed" Fre@uency offset handover decision is madeaccordin! to the upin%downin% 7 eve of the servin! ce and the path oss of nei!hborin! ces"

9uic% PBGT handover

9uic% PBGT handover decision is made accordin! to the path oss of nei!hborin! ces"

For @uic% handover# the handover response speed is enhanced by?

&ccuratey cacuatin! the movin! speed of the MS

Derestrictin! the interva between handover decisions

7educin! the number of measurement reports for the handover decision

)ntroducin! the apha fiterin!

;uic Handover !reparation

The preparation for @uic% handover invoves the foowin! aspects?

Fre@uency offset is decoded from the measurement report"

Fre@uency offset of the MS is obtained from the upin% measurement report that the BTS sends to theBSC"

&pha fiterin! is performed on the measurement report"


Durin! handover decision# it is first determined whether the tri!!erin! conditions of fre@uency offsethandover are met" hen the BTS cannot send the fre@uency offset information or the reportedfre@uency offset information is invaid# @uic% PBGT handover is tri!!ered# provided that other conditionsof fre@uency offset handover are met"

)f ;#CH+"is set toes# the tri!!erin! conditions of @uic% handover are as foows?

The MS is movin! away from the servin! ce 0the fre@uency offset in the measurement resut is ane!ative vaue5 and the movin! speed of the MS is !reater than /+:$!&TH$"

The fitered upin% eve of the servin! ce is ower than H+!T#"

The compensated downin% eve of the servin! ce is ower than H+&+4"T#"The path oss of confi!ured chain nei!hborin! ces is ower than the specified threshod of the path

oss of the servin! ce" )n other words# PBGT0n5 is !reater than or e@ua to ."

The tri!!erin! conditions of @uic% handover are as foows?

)f the ast three conditions are met simutaneousy# the decision is made as foows?

)f the first condition is met# a fre@uency offset handover is performed"

)f the first condition is not met# a @uic% PBGT handover is performed"

)f a the ast three conditions are not met# @uic% handover is not tri!!ered"


The tar!et ce must be a chain nei!hborin! ce of the servin! ce" The tar!et ce can be obtained


Copyri!ht 6 Huawei


)ssue ./ 01./.2.324.5


43/136

GSM BSS


throu!h the settin! of #$CHA#""CLL" )f H++CA$T"is set to es# a nei!hborin! ce in themovin! direction of the MS is seected preferentiay"

To forecast the movin! direction of the MS# the direction of a chain nei!hborin! ce 0& or B5 comparedwith the servin! ce is specified by CHA#""CLLT!" )f the number of times that the MS is handed

over to nei!hborin! ces in the same direction 0B for e+ampe5 is !reater than or e@ua toH+LA$TT#/when the handover time reaches H+$TAT#/# then the MS is inferred to bemovin! towards the B direction" Subse@uenty# the MS is preferentiay handed over to the nei!hborin!ce whose CHA#""CLLT!is B"

Limitations

The imitations on @uic% handover are as foows?


The candidate ces for @uic% handover must be chain nei!hborin! ces of the servin! ce" -ach cecan be confi!ured with a ma+imum of three chain nei!hborin! ces"

&fter a @uic% handover is successfu# the penaty is performed on the ori!ina ce durin! the penatytime to prevent an immediate handover bac% to the ori!ina ce" The penaty time and penaty vaueare specified by T#/!"#$Hand H+!"#$H:ALrespectivey"

%.6.2 TA Handover

T& handover is a type of emer!ency handover" The T& handover decision is made accordin! to the T&vaue reported by the MS"

The T& vaue of a norma ce ran!es from . to 34 and that of an e+tended ce ran!es from . to 11="The T& can be stepped up or down in steps of ;;4"; m" The T& vaue of 34 corresponds to a distance of4; %m"

Triggering ConditionsT& handover is tri!!ered when the foowin! conditions are met?

TAH+"is set toes"

Fitered T& vaue in the measurement report provided by the MS is !reater than or e@ua to TAL#/#T"

The T& handover can be tri!!ered ony when the precedin! two conditions are met simutaneousy"

From the perspective of the tri!!erin! conditions of T& handover# T& can be re!arded as a imitation to the siAe of a ce"


The tar!et ce shoud have the hi!hest priority in the candidate ce ist after handover preprocessin!" )naddition# the tar!et ce shoud meet the foowin! imitations?


)f TAL#/#Tof a co2site nei!hborin! ce is ower than or e@ua to the TAL#/#Tof the servin! ce# ahandover to the nei!hborin! ce is prohibited"

)n handover a!orithm ))# a ce becomes the tar!et ce for T& handover if the previous conditions aremet for TALA$TT#/within TA$TATT#/"

)f the tri!!erin! conditions of T& handover are met but the candidate 1G ces are not suitabe# thefoowin! operations are performed?



Copyri!ht 6 Huawei


1=


44/136


GSM BSS

Handover


Limitations

&fter the T& handover is successfu# the penaty is performed on the ori!ina ce" Durin!T#/TA!"#$H# $$TA!"#$His subtracted from the eve of the ori!ina ce to prevent an immediatehandover bac% to the ori!ina ce"

%.6.% -; Handover

B9 handover is a type of emer!ency handover in which the system ma%es the decision based on theupin%downin% 7 @uaity on the 'm interface"

7 @uaity is represented by bit error rate 0B-75" The BSC measures the @uaity of a radio in% basedon the @uaity cass in the measurement report" The probabe cause of an increase in B-7 is that thesi!na power is too ow or the channe interference increases"


)f -;H+"is set toes# the tri!!erin! conditions of B9 handover are as foows?

The upin% 7 @uaity is !reater than or e@ua to the upin% 7 @uaity threshod of the servin! ce"

The downin% 7 @uaity is !reater than or e@ua to the downin% 7 @uaity threshod of the servin!ce"

The B9 handover is tri!!ered when either of the precedin! conditions is met"


For non2&M7 cas# the parameter for specifyin! the upin% 7 @uaity threshod is L;AL#/#Tandthe parameter for specifyin! the downin% 7 @uaity threshod is &L;AL#/#T"

For &M7 F7 cas# the parameter for specifyin! the upin% 7 @uaity threshod isL;AL#/#TA/5and the parameter for specifyin! the downin% 7 @uaity threshod is&L;AL#/#TA/5"

For &M7 H7 cas# the parameter for specifyin! the upin% 7 @uaity threshod isL;AL#/#TA/Hand the parameter for specifyin! the downin% 7 @uaity threshod is&L;AL#/#TA/H"



)n handover a!orithm ))# the servin! ce cannot be seected as the tar!et ce"

The 7 eve of tar!et ce must meet the foowin! conditions?

The servin! ce and the tar!et ce wor% in the same fre@uency"

Fitered downin% 7 eve of the tar!et ce Fitered downin% 7 eve of the servin! ce K0#"TCLLH$Tof the servin! ce confi!ured for the nei!hborin! ce 2 3:5 2 0-;/A#"2 3:5

The servin! ce wor%s in GSM=.. and the tar!et ce wor%s in DCS/8.."

Fitered downin% 7 eve of the tar!et ce H+TH$K 0L:H+H$T2 3:5"

The servin! ce wor%s in DCS/8.. and the tar!et ce wor%s in GSM=.."

There is no constraint on the tar!et ce in this condition"

)n handover a!orithm ))# a ce becomes the tar!et ce for B9 handover if the previous conditions are

4. Huawei Proprietary and Confidentia

Copyri!ht 6 Huawei


)ssue ./ 01./.2.324.5


45/136

GSM BSS


met for -;LA$TT#/within -;$TATT#/"

)f the tri!!erin! conditions of B9 handover are met but the candidate 1G ces are not suitabe# thefoowin! operations are performed?



Limitations

&fter the B9 handover is successfu# the penaty is performed on the ori!ina ce" Durin!T#/-;!"#$H# $$-;!"#$His subtracted from the eve of the ori!ina ce to prevent animmediate handover bac% to the ori!ina ce"

%.6.6 #nter3erence Handover)nterference handover is a type of intra2ce handover in handover a!orithm ))"

)nterference handover heps protect the interfered cas and reduce the networ% interference" )t isappicabe to scenarios with interference"

)n handover a!orithm ))# the B9 handover is a type of emer!ency handover and the interferencehandover is a type of intra2ce handover"


)f #"TACLLH+"is set toesand #"T5H+"is set toes# the tri!!erin! conditions ofinterference handover are as foows?

The fitered vaue of upin% 7 @uaity is !reater than or e@ua to the specified 7 @uaity threshod atthe current upin% 7 eve"

The fitered vaue of downin% 7 @uaity is !reater than or e@ua to the specified 7 @uaity threshodat the current downin% 7 eve"

)n handover a!orithm ))# the interference handover is tri!!ered when the previous conditions are metfor #"T5LA$TT#/within #"T5$TATT#/"


For non2&M7 F7 cas# the parameter for specifyin! the 7 @uaity threshod is ;ALn# where / Vn V /1"

For &M7 F7 cas# the parameters for specifyin! the 7 @uaity threshod are ;ALn0/ V n V /15and L:+55"

)f n /# the 7 @uaity threshod is ;AL1"

)f 1 V n V /1# the 7 @uaity threshod is ;ALnK L:+55"


)n handover a!orithm ))# ony the servin! ce can be seected as the tar!et ce"

Limitations

)n handover a!orithm ))# if an interference handover is initiated# it cannot be initiated a!ain within#"T5H+!"T#/re!ardess of whether the handover is successfu"


Copyri!ht 6 Huawei


4/


46/136


GSM BSS

Handover

%.6.7 Handover &ue to "o &ownlin /easurement eport

Handover due to no downin% measurement report is performed on the basis of the upin% @uaity" Thepurpose is to ensure the ca continuity and minimiAe the possibiity of ca drops"

Handover due to no downin% measurement report is !eneray caused by adverse radio environmenton the upin%" )n this case# the re@uirements of the fiterin! a!orithm cannot be met# so other handoverdecisions cannot be performed"


)n handover a!orithm ))# the tri!!erin! conditions of handover due to no downin% measurement reportare as foows?

"+&L/H+"is set toes"

There is no downin% information in the measurement report of the ca"

The number of ost downin% M7s is smaer than "+&L/H+ALL+4L#/#T"

For TCH# the number of saved M7s with upin% @uaity vaue is !reater than &ATA;A5LTL" forSDCCH# the number of saved M7s with upin% @uaity vaue is !reater than ;L"$#"

The fitered vaue of upin% 7 @uaity is !reater than or e@ua to L;AL#/#T"

For &M7 F7 cas# the correspondin! parameter is L;AL#/#TA/5"

For &M7 H7 cas# the correspondin! parameter is L;AL#/#TA/H"

hen a the previous conditions are met# the handover due to no downin% measurement report istri!!ered"


)n handover a!orithm ))# the conditions for seectin! the tar!et ce are as foows?

The ran%ed nei!hborin! ces recorded in the ast compete measurement report are saved ascandidate ces"

>ny a nei!hborin! ce can serve as the tar!et ce"

7 eve in nei!hborin! ce Fitered 7 eve in servin! ce K 0#"TCLLH$T2 3:5 20-;/A#"2 3:5

& nei!hborin! ce serves as the tar!et ce if the previous conditions are met for L-;LA$TT#/within L-;$TATT#/"

%.6.) nhanced &ual(-and "etwor Handover

-nhanced dua2band networ% handover is performed based on the traffic voume of the overaid andunderaid ces and based on the receive eve"

-nhanced dua2band networ% handover is cassified into the foowin! types?

Handover due to hi!h oad in the underaid ce

Handover due to ow oad in the underaid ce

Handover due to MS movement to the border of the overaid ce

Triggering Conditions o3 Handover &ue to High Load in the nderlaid Cell

The tri!!erin! conditions of the handover due to hi!h oad in the underaid ce are as foows?

The two ces are in the enhanced dua2band networ% and +TL+A&H+"A-Lis set toes"

The MS supports the fre@uency band on which the overaid ce operates"


Copyri!ht 6 Huawei


)ssue ./ 01./.2.324.5


47/136

GSM BSS


The handover due to hi!h oad in the underaid ce is performed ony on TCHs"

The oad in the underaid ce is hi!her than or e@ua to +T"+:L&TH&"

The oad in the overaid ce is ower than #""$#+:L&TH&"


The current ca is within the handover mar!in and the receive eve is !reater than or e@ua to#"T+#""L:TH&"

hen a the precedin! conditions are met# the handover due to hi!h oad in the underaid ce istri!!ered"

)f the oad of the underaid subce is hi!her than or e@ua to +T$#+:L&TH then thehandover mar!in is ad,usted in a period of +TL+A&H+!#+&subtracted by+TL+A&H+/+&!#" The step en!th for handover mar!in ad,ustment is specified by+TL+A&H+$T!"

Triggering Conditions o3 Handover &ue to Low Load in the nderlaid Cell

The tri!!erin! conditions of the handover due to ow oad in the underaid ce are as foows?

The oad in the underaid ce is ower than +TL+4L+A&TH&"


The current ca is within the handover mar!in and the receive eve is !reater than or e@ua to+T#""L:TH&"

hen a the precedin! conditions are met# the handover due to ow oad in the underaid ce istri!!ered"

)f the oad of the underaid subce is ower than +TL+4L+A&TH&for a specified period# then thehandover mar!in is ad,usted in a period of #""L+A&H+!#" The step en!th for handover mar!in

ad,ustment is specified by #""L+A&H+$T!"

Triggering Conditions o3 Handover &ue To /$ /ovement in the +verlaid$u


48/136


GSM BSS

Handover

conditions is met"

For the &TCB handover a!orithm# the boundaries of the overaid and underaid subces are determined accordin! tothe reative vaue between the si!na stren!th of servin! ce and that of nei!hborin! ce" hen SS0s5 is e@ua toSS0n5# the system considers that it is the boundary point of the underaid subce" hen the vaue of SS0s5 subtractedby SS0n5 is !reater than &TCBTH7D# it is the covera!e area of the overaid subce" The covera!e area of theoveraid subce is determined accordin! to different networ%in! and covera!e conditions of the e+istin! networ%" )naddition# the overaid subce of servin! ce and the overaid subce of nei!hborin! ces wi not overap re!ardess ofthe distance between BTSs"

The handover mar!in specifies the ran!e of si!na eve" )n the case of overaidunderaid oad handover on theenhanced dua2band networ%# the MSs whose downin% eves are within the handover mar!in are handed over eveby eve"


The re@uirements for tar!et ce seection in the enhanced dua2band networ% are as foows?

For the handover due to hi!h oad in the underaid ce# the MS must be handed over to the overaid

ce"For the handover due to ow oad in the underaid ce# the MS must be handed over to the underaid

ce"

For the handover due to MS movement in the overaid subce# the MS must be handed over to theunderaid ce"

Limitations

The imitations on the handover due to hi!h oad in the underaid ce are as foows?

)f the ce where the ca is ocated is on an enhanced dua2band networ%# CLL#"T!is set to8tra'8tra*"

The +TL+A&H+"A-Lparameter shoud be set"The ma+imum ran!e of the handover mar!in is from 34 to #"T+#""L:TH&" The MS with

the hi!hest receive eve is handed over first"

The imitations on the handover due to ow oad in the underaid ce are as foows?


The #""L+A&H+"parameter shoud be set"

The ma+imum ran!e of the handover mar!in is from 34 to +T#""L:TH&" The MS with theowest receive eve is handed over first"

The imitations on the handover due to MS movement in the overaid subce are described as foows?

The ce where the ca is ocated is on the enhanced dua2band networ%" CLL#"T!is set to#nner'#nner*"

#mpact o3 the nhanced &ual(-and "etwor Handover on the 8istingAlgorithm

The impact of the enhanced dua2band networ% handover on the e+istin! a!orithm is as foows?

>n the enhanced dua2band networ%# the MS shoud not be handed over to a ce in the sameunderaidoveraid ce !roup when the oad handovers between the overaid ce and the underaid ce0specified by +TL+A&H+"A-Land #""L+A&H+"5 are aowed" This is to prevent a oadhandover of a norma ce from coidin! with a oad handover between the overaid ce and the

underaid ce on the networ%"

4: Huawei Proprietary and Confidentia

Copyri!ht 6 Huawei


)ssue ./ 01./.2.324.5


49/136

GSM BSS


%.6.9 Load Handover

)n handover a!orithm ))# oad handover is not decided independenty"

)n handover a!orithm ))# the oad handover decision is made in networ% ad,ustment phase" The

seection of tar!et ce shoud be processed by the better ce handover" That is# the oad handover istri!!ered when the tri!!erin! conditions of oad handover and better ce handover are metsimutaneousy"

See 4"4"8 $oad Handoverfor the tri!!erin! conditions of oad handover" See 4":"/. Better CeHandoverfor the tri!!erin! conditions of better ce handover"

"he ranges of load handover margins are defined as follows#

$oad hand

Handover.doc

Documents

Transcript of Handover.doc