Upload
paul-kabeya
View
233
Download
5
Embed Size (px)
Citation preview
8/11/2019 08 GSM BSS Network KPI (Immediate Assignment Success Rate) Optimization Manual.doc
1/34
GSM BSS Network KPI (Immediate Assignment Success Rate) Optimization Manua IN!"RNA#
Product Name Confidentiality LevelGSM BSS INTERNALProduct Version Total ! "a#es
GSM BSS Net$or% &PI 'Immediate
Assi#nment Success Rate( )"timi*ationManual
'+or internal use only(
Pre"ared ,y GSM-.MTSNet$or% PerformanceResearc/ 0e"artment
1an# +ei
0ate2334536574
Revie$ed ,y 0ate Revie$ed ,y 0ate
Granted ,y 0ate
8ua$ei Tec/nolo#ies Co9: Ltd
All ri#/ts reserved
$%%&' %'$ All Ri#/ts Reserved Page o* +,
8/11/2019 08 GSM BSS Network KPI (Immediate Assignment Success Rate) Optimization Manual.doc
2/34
GSM BSS Network KPI (Immediate Assignment Success Rate) Optimization Manua IN!"RNA#
Revision Record
Date RevisionVersion
Change Description Author
2334536574 394 0raft com"leted9 1an# +ei
233453;574 793 T/e document is modified accordin# torevie$ comments9
1an# +ei
$%%&' %'$ All Ri#/ts Reserved Page $ o* +,
8/11/2019 08 GSM BSS Network KPI (Immediate Assignment Success Rate) Optimization Manual.doc
3/34
GSM BSS Network KPI (Immediate Assignment Success Rate) Optimization Manua IN!"RNA#
ReferencesNumber References Author Date
7 GSM BSS Net$or% &PI 'Immediate Assi#nment Success Rate( Baseline Liu
8/11/2019 08 GSM BSS Network KPI (Immediate Assignment Success Rate) Optimization Manual.doc
4/34
GSM BSS Network KPI (Immediate Assignment Success Rate) Optimization Manua IN!"RNA#
Content7 )vervie$ of t/e Immediate Assi#nment Success Rate99999999999999999999999999999999999999999999797 0efinition99999999999999999999999999999999999999999999999999999999999999999999999999792 Si#nalin# Procedure and Measurement Points99999999999999999999999999999999999999999999979 Sym"tom 0escri"tion99999999999999999999999999999999999999999999999999999999999999999
2 +actors Concernin# Immediate Assi#nment Success Rate999999999999999999999999999999999999999297 Si#nalin# +actors9999999999999999999999999999999999999999999999999999999999999999999292 +actor Analy*in# Accordin# to t/e 0efinition of t/e &PI999999999999999999999999999999999999929 +actors Analysis999999999999999999999999999999999999999999999999999999999999999999999
29 97 E>ui"ment +aults9999999999999999999999999999999999999999999999999999999999999999929 92 .m Interface Pro,lems9999999999999999999999999999999999999999999999999999999999999929 9 S0CC8 Con#estion999999999999999999999999999999999999999999999999999999999999999929 9! MS Pro,lems999999999999999999999999999999999999999999999999999999999999999999999Met/od of Analy*in# t/e Pro,lem of Lo$ Immediate Assi#nment Success Rate9999999999999999972
97 Process of Analy*in# t/e Pro,lem of Lo$ Immediate Assi#nment Success Rate99999999997292 Met/od of Solvin# t/e Pro,lem of Lo$ Immediate Assi#nment Success Rate9999999999999997!
9297 E>ui"ment +aults99999999999999999999999999999999999999999999999999999999999999999
9292 .m Interface Pro,lem999999999999999999999999999999999999999999999999999999999999999929 System Ca"acity 'Con#estion( Analysis9999999999999999999999999999999999999999999999999929! MS Pro,lem Analysis99999999999999999999999999999999999999999999999999999999999999
! Test Met/od9999999999999999999999999999999999999999999999999999999999999999999999999999? Cases of Immediate Assi#nment Success Rate )"timi*ation99999999999999999999999999999999999999?97 Case 7@ 0ecrease in Immediate Assi#nment Success Rate Because of S0CC8
Con#estion Caused ,y Incorrect LAC Settin#9999999999999999999999999999999999999999999999999?92 Case 2@ S0CC8 Con#estion Caused ,y a Burst of Location ."dates9999999999999999999999999992?9 Case @ Lo$ Assi#nment Success Rate Because t/e RAC8 Minimum Access Level Is
Set to 39999999999999999999999999999999999999999999999999999999999999999999999999999999?9! Case !@ Lo$ Immediate Assi#nment Success Rate in Some Cells Because of MS Error
36 )nsite Information t/at Needs to Be ),tained99999999999999999999999999999999999999999999999999
$%%&' %'$ All Ri#/ts Reserved Page , o* +,
8/11/2019 08 GSM BSS Network KPI (Immediate Assignment Success Rate) Optimization Manual.doc
5/34
GSM BSS Network KPI (Immediate Assignment Success Rate) Optimization Manua IN!"RNA#
TablesTa,le 7 Ma""in# ,et$een formulae and factors9999999999999999999999999999999999999999999999999999
$%%&' %'$ All Ri#/ts Reserved Page o* +,
8/11/2019 08 GSM BSS Network KPI (Immediate Assignment Success Rate) Optimization Manual.doc
6/34
GSGSM BSS Network KPI (Immediate Assignment Success Rate) Optimization Manua IN!"RNA#
GSM BSS Net$or% &PI 'Immediate Assi#nment
Success Rate( )"timi*ation Manual
AbstractKey Words: DCC!" immediate assignment success rate
Abstract: This document provides the procedure for analy#ing theproblems about immediate assignment success rate" describes the
troubleshooting procedure" and provides typical cases$Abbreviations:
Abbreviation %ull pelling
BSC Base Station Controller BTS Base Tranceiver StationS0CC8 Stand5alone 0edicated Control
C/annel
$% ,' %' + -uawei !ec.no ogies Proprietar/ Page 0 o* +,
8/11/2019 08 GSM BSS Network KPI (Immediate Assignment Success Rate) Optimization Manual.doc
7/34
GSGSM BSS Network KPI (Immediate Assignment Success Rate) Optimization Manua IN!"RNA#
1 &vervie' of the (mmediate Assignment
uccess Rate
Immediate assi#nment success rate indicates t/e success rate of t/e MS accessin#t/e si#nalin# c/annel9 It concerns t/e "rocedure from t/e MS sendin# a c/annel re>uiredmessa#e to t/e BTS to t/e MS sendin# an esta,lis/ indication messa#e to t/e net$or%9
Immediate assi#nment success rate is a %ey access counter9 It directly reflects t/e
success rate of t/e MS accessin# t/e si#nalin# c/annel and affects t/e user e "erience9
T/e BSC versions concerned in t/is document are as follo$s@
BSC 2 G BSC 2V 33R33;C37B37?
BSC6333 BSC6333V=33R337
1 0efinition
T/e immediate assi#nment success rate is calculated from traffic statistics9 T/e
recommended formula is as follo$s@Immediate Assi#nment Success Rate 'Successful Immediate
Assi#nmentsDImmediate Assi#nment Re>uests( 733
$% ,' %' + -uawei !ec.no ogies Proprietar/ Page 2 o* +,
8/11/2019 08 GSM BSS Network KPI (Immediate Assignment Success Rate) Optimization Manual.doc
8/34
GSGSM BSS Network KPI (Immediate Assignment Success Rate) Optimization Manua IN!"RNA#
1$ Si#nalin# Procedure and Measurement Points
BSCBTS MSC
Channel REQ
Channl RQD
Channel ACT
Channel ACT ACK
IMM ASS CMD
first SABM
UAEST IND(CM Service REQ)
CR(CMP L inf!r"ati!n)
CC
CM Service Acce#te$
A%
C%
B%
Note@
A7@ Immediate Assi#nment Re>uests 'C/annel Re>uests 'Circuit Service((
B7@ Immediate Assi#nment Commands
C7@ Successful Immediate Assi#nments 'Call Setu" Indications 'Circuit Service((
1+ Sym"tom 0escri"tion
If t/e immediate assi#nment success rate decreases: t/e follo$in# sym"toms may
occur@
Call setu" success rate decreases9
$% ,' %' + -uawei !ec.no ogies Proprietar/ Page & o* +,
8/11/2019 08 GSM BSS Network KPI (Immediate Assignment Success Rate) Optimization Manual.doc
9/34
GSGSM BSS Network KPI (Immediate Assignment Success Rate) Optimization Manua IN!"RNA#
Con#estion occurs fre>uently on t/e S0CC89
Traffic volume on t/e TC8 decreases9
S/ort messa#es cannot ,e successfully sent9FF
2 %actors Concerning (mmediate Assignment
uccess Rate
$1 Si#nalin# +actors
Accordin# to t/e si#nalin# flo$: t/e factors concernin# t/e immediate assi#nment
success rate durin# eac/ "/ase are as follo$s@
( ) Random access re>uest "/ase@ $/et/er t/e small interference si#nal on t/e .m
interface is re#arded as t/e random access re>uest ,y t/e BSC9 Affectin# factor@
.m interface "ro,lems
($) S0CC8 assi#nment "/ase@ $/et/er t/e S0CC8 is availa,le after t/e random
access re>uest is acce"ted9 Affectin# factor@ S0CC8 con#estion
(+) C/annel activation "/ase@ $/et/er t/e c/annel activation is successful after t/e
c/annel assi#nment succeeds9 Affectin# factor@ C8AN ACTIV NAC& messa#e is
received ,ecause of e>ui"ment faults durin# S0CC8 activation
(,) Immediate assi#nment command "/ase@ $/et/er t/e timer for t/e
ac%no$led#ment of t/e immediate assi#nment e "ires9 Affectin# factor@ .m
interface "ro,lems( ) Lin% esta,lis/ment "/ase@ $/et/er t/e lin% can ,e esta,lis/ed on t/e S0CC8
after t/e immediate assi#nment command is sent9 Affectin# factor@ MS features9
T/e follo$in# analysis is ,ased on t/ese factors9
$1$ +actor Analy*in# Accordin# to t/e 0efinition of t/e &PI
As s/o$n in t/e "revious section: t/e follo$in# four factors are related to immediateassi#nment success rate@ .m interface "ro,lems: S0CC8 con#estion: rece"tion of
$% ,' %' + -uawei !ec.no ogies Proprietar/ Page 3 o* +,
8/11/2019 08 GSM BSS Network KPI (Immediate Assignment Success Rate) Optimization Manual.doc
10/34
8/11/2019 08 GSM BSS Network KPI (Immediate Assignment Success Rate) Optimization Manual.doc
11/34
GSGSM BSS Network KPI (Immediate Assignment Success Rate) Optimization Manua IN!"RNA#
$1+ +actors Analysis
$1+1 E>ui"ment +aults
$1+1 1 Lo$ Immediate Assi#nment Success Rate Caused ,y TR< +aults
Generally: rece"tion of C8AN ACTIV NAC& durin# t/e S0CC8 activation is caused
,y e>ui"ment faults9 If one TR< fails in t/e cell confi#ured $it/ multi"le TR
8/11/2019 08 GSM BSS Network KPI (Immediate Assignment Success Rate) Optimization Manual.doc
12/34
8/11/2019 08 GSM BSS Network KPI (Immediate Assignment Success Rate) Optimization Manual.doc
13/34
GSGSM BSS Network KPI (Immediate Assignment Success Rate) Optimization Manua IN!"RNA#
t/e ran#e in $/ic/ t/e "ro,lem e ists: and t/en find out t/e factors related to t/e "ro,lem
accordin# to &PI statistical formulae9 +or details: see section 292 +actor Analy*in#
Accordin# to t/e 0efinition of t/e &PI 9 In t/e case of recommended formula: t/e #eneral
"rocess of analy*in# t/e "ro,lem is as follo$s@
Start
Analysis of lo$immediate assi#nment
success rate
C/ec% num,er of S0CC8 activation
failuresDtimeout
C/ec%S0CC8
availa,lity
C/ec% TRuality
analysis
RAC8overload
times
SolveInterference "ro,lem
S0CC8 sei*uresuccess rate
'location u"date(
C/ec% timersrelated tolocationu"date
C/ec% S0CC8dynamic
confi#uration
Traffic volume"er S0CC8
e ceeds "aln
S0CC8 andTC8 traffic
volumeanalysis
Incomin# andout#oin#
/andovers of t/e cell
Re"lan t/elocationareas
No
Insufficient systemca"acityM
A,normal
Normal
8ard$aree "ansion
E>ui"ment fault
.m interfacefault
es
es
No
es
Pro,lemsolved
es
End
+ind cells $it/ lo$immediate assi#nment
success rate
MS fault Analy*e si#nalin# andtraffic statistics of cells
$it/ "ro,lem
Ena,le CBA
of t/e cell
+or s$a""ed net$or%:c/ec% $/et/er t/e
"ro,lem e ists inventorNs net$or%
No
Locate"ro,lem
and su,mitre"ort
$% ,' %' + -uawei !ec.no ogies Proprietar/ Page + o* +,
8/11/2019 08 GSM BSS Network KPI (Immediate Assignment Success Rate) Optimization Manual.doc
14/34
GSGSM BSS Network KPI (Immediate Assignment Success Rate) Optimization Manua IN!"RNA#
4igure Process of analy*in# t/e "ro,lem of lo$ immediate assi#nment success rate
+1$Met/od of Solvin# t/e Pro,lem of Lo$ Immediate Assi#nment Success
Rate
Before analy*in# t/e cause of lo$ immediate assi#nment success rate: you s/ould
find out t/e difference ,et$een t/e actual immediate assi#nment success rate and t/e
e "ected value9 ou s/ould also find out t/e influence of t/e "ro,lem and t/e definition of
t/e s"ecific immediate assi#nment success rate &PI9
+1$1 E>ui"ment +aultsT/is "art aims to solve TR< or transmission "ro,lems9
+irstly: you s/ould c/ec% TR, Availability in - C )easurement and DCC!
Availability in DCC! )easurement 9 Secondly: you s/ould c/ec% t/e num,er of times
t/at a NAC& messa#e is received or t/e timer e "ires durin# t/e S0CC8 activation9 In
t/is $ay: you can determine $/et/er t/e "ro,lem is caused ,y ,oard faults9
ou can also c/ec% $/et/er /ard$are is faulty ,y vie$in# BTS alarms or ,y vie$in#t/e /ard$are state on ite Device *anel of t/e LMT9 ou can c/ec% t/e follo$in# trafficstatistics for reference@
Cause - C +evel Cell +evelE>ui"ment faults
BSC Measurement 5O Accessmeasurement "er BSC 5OS0CC8 Availa,ility "er BSCConfi#ured S0CC8s "er BSC Availa,le S0CC8s "er BSC
Call Measurement 5O C/annel ActivationMeasurement "er Cell 5O S0CC8Connection Measurement "er Cell 5OC8AN ACTIV NAC& Messa#es Sent ,yBTS in Immediate Assi#nment Procedure
'S0CC8(C/annel Activation Timeouts in Immediate Assi#nment Procedure 'S0CC8(&PI Measurement "er Cell 5O TC8 Availa,ility
+1$1$ .m Interface Pro,lem
+1$1$1 Mista%enly Re#ardin# Interference as Random Access Re>uests
Interference may cause S0CC8 con#estion: causin# lo$ immediate assi#nment$% ,' %' + -uawei !ec.no ogies Proprietar/ Page , o* +,
8/11/2019 08 GSM BSS Network KPI (Immediate Assignment Success Rate) Optimization Manual.doc
15/34
GSGSM BSS Network KPI (Immediate Assignment Success Rate) Optimization Manua IN!"RNA#
success rate9 Es"ecially in t/e areas $it/ a small s"ace ,et$een BTSs and dense BCC8fre>uency "lannin#: t/e system allocates S0CC8 for eac/ si#nal if a lar#e num,er of interference si#nals are received9 T/us: t/e con#estion may occur9 In t/is situation: t/eimmediate assi#nment success rate and "a#in# success rate decrease: and t/e RAC8may ,e overloaded9 ou can locate t/e "ro,lems ,y analy*in# t/e idle interference ,andsand t/e TR< receive >uality durin# t/e call9
If t/e system mista%enly re#ards t/e interference as a random access si#nal and
sends an assi#nment command: t/e immediate assi#nment $ill fail9 ou can locate t/e
"ro,lem ,y analy*in# t/e C/an Re> messa#e9
+or t/e S0CC8 con#estion caused ,y interference: you can c/ec% t/e follo$in#
traffic statistics for reference@Cause - C +evel Cell +evel TR, +evelS0CC8con#estioncaused ,yinterference
BSC Measurement 5O Access measurement"er BSC 5ORandom AccessSuccess Ratio "er BSC
Call Measurement5O +lo$ ControlMeasurement "er Cell 5O MSG CCC8L)A0 IN0 'RAC8(Messa#es Sent on A,is Interface
MR Measurement 5O Analy*ed Measurementof Interference Band "er TRuest for sin#le timeslot u"lin%37777 3 transmission one P0C8 is needed937777 3
37773 Sin#le ,loc% "ac%et access one ,loc% "eriod on a P0C8 is
needed for t$o "/ase "ac%et access or ot/er RR si#nallin# "ur"ose9
$% ,' %' + -uawei !ec.no ogies Proprietar/ Page 2 o* +,
8/11/2019 08 GSM BSS Network KPI (Immediate Assignment Success Rate) Optimization Manual.doc
18/34
GSGSM BSS Network KPI (Immediate Assignment Success Rate) Optimization Manua IN!"RNA#
37733777 LM. esta,lis/ment note 2
37733 3 Reserved for future use37733 3737733377 note 2a
37777777 Reserved for future use9 note 2,
N)TE 7@ E am"les of t/ese "rocedures are@ IMSI detac/: S/ort Messa#e Service 'SMS(:Su""lementary Service mana#ement: Location Services9
N)TE 2@ If suc/ messa#es are received ,y a net$or%: an S0CC8 s/all ,e allocated9
N)TE 2a@ If suc/ messa#es are received ,y a net$or%: an S0CC8 may ,e allocated9
N)TE 2,@ T/is value s/all not ,e used ,y t/e mo,ile station on RAC89 If suc/ messa#e isreceived ,y t/e net$or%: it may ,e i#nored9
29 T/e value ofAccess Delay indicates t/e TA99 Bits 7 : 7!: 7?: and 76 indicate t/e RAC8 level and t/e num,er of error ,its in t/etrainin# se>uence9 In t/is e am"le: t/e value of ,it 7 is ! 9 T/is indicates t/at t/e,its follo$ed indicate t/e AB access level and t/e num,er of error ,its in t/e trainin#se>uence9 T/e value of ,it 7! is 29 T/is indicates t/at t/e follo$in# t$o ,its indicate
t/e AB access level and t/e num,er of error ,its in t/e trainin# se>uence9 T/e valueof ,it 7? indicates t/e RAC8 level ' = Q 723 Q47 dBm(9
+1$1$1$ Covera#e 0ifference
If t/e com,ination mode of t/e BCC8 TR< and t/e non5BCC8 TR< is different: or
t/e losses are inconsistent ,ecause of different transmit "o$er or ot/er "ro,lems: t/e
assi#nment on t/e non5BCC8 TR< may fail9
T/e causes can ,e classified into t/ree ty"es@ T/e transmit "o$er of TR
8/11/2019 08 GSM BSS Network KPI (Immediate Assignment Success Rate) Optimization Manual.doc
19/34
GSGSM BSS Network KPI (Immediate Assignment Success Rate) Optimization Manua IN!"RNA#
antennae may cause assi#nment failure9 ou can solve t/is "ro,lem t/rou#/ en#ineerin#
adJustment9
T/e transmit and receive antennae are not on t/e same /ori*ontal "lane or t/eir
tilts are not t/e same9 ou can solve t/is "ro,lem ,y adJustin# t/e antennae9
+1$1+ System Ca"acity 'Con#estion( Analysis
+1$1+1 Con#estion Caused ,y 8eavy Traffic on t/e S0CC8
Generally: /eavy traffic on t/e S0CC8 is caused ,y fre>uent location u"dates9 ou
can c/ec% t/e rate of t/e S0CC8 ,ein# occu"ied ,y >ueryin# t/e counter Channel
Re/uests 0+ocation ;pdating2 and t/e total num,er of c/annel re>uests9 +i#ure
s/o$s t/e ratios of different %inds of S0CC8 re>uests to t/e total num,er of S0CC8
re>uests on S/an#/ai .nicom $/en t/e traffic is /eavy9 If t/e ratios are /i#/: c/ec% t/e
location area "lannin# and t/e drive test result9 If t/e ed#es of location areas are
confi#ured in t/e area $it/ /eavy traffic: reconfi#ure t/e location areas9 In addition: you
can adJust t/e C8R "arameters to reduce location u"dates9 +or details: see Case < 9If t/e S0CC8 con#estion rate is /i#/ '#reater t/an ? (: t/e traffic volume on eac/
S0CC8 may /ave e ceeded t/e limit as "lanned9 ou s/ould c/ec% t/e confi#uration of
t/e location u"date and S0CC8 dynamic confi#uration "arameters9 If t/e settin#s of
"arameters are reasona,le: a /ard$are ca"acity e "ansion is re>uired9
If t/e con#estion rate and traffic volume of t/e S0CC8 are /i#/: ,ut t/e traffic
volume of t/e TC8 is normal: t/e S0CC8 con#estion may ,e caused ,y ,urst traffic9 +or
t/e sites alon# t/e rail$ay: es"ecially for t/ese near t/e tunnel "ortal: t/e ca"acity
confi#ured is #enerally small9 1/en a train "asses t/rou#/ or sto"s: a lar#e num,er of
location u"dates occur: $/ic/ finally lead to S0CC8 con#estion9 In addition: durin# t/e
"eriod $/en t/e volume of s/ort messa#es is lar#e: S0CC8 con#estion may occur9 T/is
"ro,lem cannot ,e com"letely solved: ,ut you can ta%e some measures to alleviate t/e
con#estion9 +or e am"le: confi#ure more S0CC8s: or ena,le t/e dynamic conversion
,et$een t/e S0CC8 and TC89 +or details: see Case = 9
$% ,' %' + -uawei !ec.no ogies Proprietar/ Page 3 o* +,
8/11/2019 08 GSM BSS Network KPI (Immediate Assignment Success Rate) Optimization Manual.doc
20/34
8/11/2019 08 GSM BSS Network KPI (Immediate Assignment Success Rate) Optimization Manual.doc
21/34
8/11/2019 08 GSM BSS Network KPI (Immediate Assignment Success Rate) Optimization Manual.doc
22/34
GSGSM BSS Network KPI (Immediate Assignment Success Rate) Optimization Manua IN!"RNA#
tries to find a TC8+ t/at can ,e converted into anS0CC89 T/is "arameter is one of t/e conditions for t/e dynamic conversion from TC8+ to S0CC89
CellS0CC8C/annelMa imum
Accordin# to t/e c/annel assi#nment al#orit/m: t/esystem determines $/et/er t/e num,er of S0CC8s int/e cell after t/e conversion e ceeds t/e value of CellS0CC8 C/annel Ma imum ,efore initiatin# t/edynamic conversion from TC8 to S0CC89 If yes: t/econversion is not initiated9
TC8MinimumRecovery
Time's(
T/is "arameter s"ecifies t/e minimum time for t/erecovery of a TC8 from t/e S0CC89
!9 Related timers and their recommended configurations are as follo's:
T 737@ T/is timer is used for immediate assi#nment "rocedure monitorin#9
Reduce t/e value of t/is "arameter "ro"erly to minimi*e t/e con#estion caused
,y dual assi#nment of t/e S0CC89 If t/e len#t/ of t/is timer is too lon#: t/e
invalid usa#e of si#nalin# resources is increased9 To en/ance t/e usa#e of t/e
si#nalin# resources: you s/ould s/orten t/e len#t/ of t/is timer: es"ecially $/en
t/e >ueuin# function is ena,led9
T 722@ T/is timer is started ,y t/e MS $/en t/e MS receives t/e IMME0IATE
ASSIGN RE ECT messa#e9 T/e MS can send a ne$ c/annel re>uest messa#e
only after T 722 e "ires9 If t/e len#t/ of T 722 is too s/ort: t/e MS may send
t/e c/annel re>uest messa#e fre>uently $/en no system resources are
availa,le9 T/is increases t/e load on t/e RAC8 and CCC89T 272@ T/is timer is used for t/e "eriodic location u"date9 Increase t/e len#t/ of
t/is timer "ro"erly to reduce t/e load on t/e S0CC8 ,rou#/t ,y "eriodic
location u"date9
T 777@ T/is timer delays t/e deactivation of c/annels after main si#nalin# lin%s
are disconnected to reserve time for re"eated lin% disconnection9 T 777 is
started durin# t/e disconnection of ,ot/ TC8 and S0CC89 T/e value of T 777
must ,e t/e same as t/e value of T 773 at t/e MS side9 Generally: t/ey are set
$% ,' %' + -uawei !ec.no ogies Proprietar/ Page $$ o* +,
8/11/2019 08 GSM BSS Network KPI (Immediate Assignment Success Rate) Optimization Manual.doc
23/34
8/11/2019 08 GSM BSS Network KPI (Immediate Assignment Success Rate) Optimization Manual.doc
24/34
GSGSM BSS Network KPI (Immediate Assignment Success Rate) Optimization Manua IN!"RNA#
739Cell -ar ualify 0C- 2 @ C- ta%es effect durin# cell selection rat/er t/an cell
reselection9+1$1, MS Pro,lem Analysis
+1$1,1 C/ec%in# t/e Pro,lem Sym"toms
),Jective@ to c/ec% t/e "ro,lems t/at e ist on site and solve t/e "ro,lems caused ,y
"oor air interface >uality and incorrect "arameter settin#s9
T/e sym"toms are listed as follo$s@
Sym"tom 7@ T/e num,er of failed S0CC8 sei*ures due to timeout is almost e>ual to
t/e num,er of location u"datin# re>uests minus t/e num,er of lin% esta,lis/ment
indications for location u"datin#9
Sym"tom 2@ T/e "ro,lem /a""ens discontinuously durin# ,ot/ ,usy /ours and idle/ours9
Sym"tom @ T/e call service is normal9 E ce"t for lo$ immediate assi#nment
success rate in a fe$ cells durin# certain "eriods: t/e &PIs and drive test result are
normal: and no call dro" com"laint is received9 Because $/en an MS fails in location
u"date: it may try to access ot/er cells or try to access t/e cell a#ain "eriodically9
Sym"tom !@ No interference and no cells $it/ t/e same BCC8 fre>uency and BSIC
e ist9
Sym"tom ?@ No a,normality suc/ as u"lin%5do$nlin% im,alance e ists9
Sym"tom 6@ T/e result of si#nalin# analysis on t/e A,is interface s/o$s t/at t/e
num,er of re>uest retransmissions and t/e retransmission interval of t/e failed location
u"dates meet t/e confi#uration re>uirements9If all t/e "revious sym"toms e ist: you can infer t/at t/e "ro,lem is lo$ immediate
assi#nment success rate caused ,y a,normal location u"date9
+1$1,1$ Pro,lem 8andlin#
As t/e "ro,lem of lo$ immediate assi#nment success rate is caused ,y some MSs:
and t/e MSs cannot ,e located ,ecause no layer5 information is "rovided in location
u"date "rocedure: t/is "ro,lem cannot ,e solved on t/e net$or% side currently9To im"rove t/e user satisfaction: do as follo$s@
$% ,' %' + -uawei !ec.no ogies Proprietar/ Page $, o* +,
8/11/2019 08 GSM BSS Network KPI (Immediate Assignment Success Rate) Optimization Manual.doc
25/34
GSGSM BSS Network KPI (Immediate Assignment Success Rate) Optimization Manua IN!"RNA#
'7( Reduce t/e im"act of a,normal MS location u"dates on t/e net$or% &PIs9
'2( Communicate t/orou#/ly $it/ customers9
*roblem handling:
If any of t/e "revious si sym"toms does not e ist: initiate t/e "rocedures for
net$or% o"timi*ation and trou,les/ootin#9
To "erform net$or% o"timi*ation accordin# to t/e RSL si#nalin#: do as follo$s@79 If t/e value of TA in t/e location u"date si#nalin# is /i#/ and t/e access level is
lo$ durin# t/e time $/en t/e "ro,lem e ists: do as follo$s@
AdJust t/e follo$in# "arameters@)a@ TA : RAC! )in Access +evel : and T@
integer 'increase S and T(9Increase t/e len#t/ of t/e follo$in# timers@T5uests received $/en t/e
"ro,lem occurred $ere sent ,y some a,normal MSs: and t/e BTS res"onded and
/andled t/e re>uests correctly9 T/e analysis is ,ased on t/e u"lin% and do$nlin%9 T/e
details are descri,ed as follo$s@
29 ."lin% Q c/annel re>uests from t/e MS
'7( 1/en t/e cell access is "ro/i,ited: t/e immediate assi#nment success rate of t/e
cell ,ecomes normal9 T/is indicates t/at t/e a,normal location u"dates are caused ,y
t/e MS rat/er t/an t/e interference9'2( T/e location u"date re>uests are $it/ /i#/ level: lo$ error rate: and small TA
$% ,' %' + -uawei !ec.no ogies Proprietar/ Page $ o* +,
8/11/2019 08 GSM BSS Network KPI (Immediate Assignment Success Rate) Optimization Manual.doc
26/34
GSGSM BSS Network KPI (Immediate Assignment Success Rate) Optimization Manua IN!"RNA#
'e ce"t for some sites $it/ $ide covera#e area(9 T/is indicates t/at t/e a,normal
location u"dates are initiated ,y t/e MS9
' ( T/e num,er of location u"date re>uests sent ,y an MS com"lies $it/ t/e settin#s
of net$or% "arameters9 T/is also indicates t/at t/e a,normal location u"dates are
initiated ,y t/e MS9
9 0o$nlin% Q immediate assi#nment
'7( T/e immediate assi#nment commands are sent correctly: ,ecause t/e values of
T7: T2: and T are t/e same as t/ose in t/e c/annel re>uests9
'2( Call access and t/e su""lementary services suc/ as s/ort messa#e are all
normal9 T/e "ro,lem only e ists in t/e S0CC8 access related to location u"date9 T/is
indicates t/at t/e immediate assi#nment commands are sent correctly9
!9 Net$or% data com"arison 'for t/e s$a""ed offices and t/e offices $it/ se#mental
net$or%in#(
By com"arin# t/e data ,efore and after s$a""in# 'for s$a""ed offices( and t/e data
of t/e surroundin# cells 'for t/e offices $it/ se#mental net$or%in#(: $e find t/at t/e
"ro,lem also e ists in t/e net$or%s of ot/er com"anies9
4 Test )ethod
Immediate assi#nment success rate is a traffic measurement counter9
As t/e formulae of t/is counter in different manufacturers and o"erators are different
currently: you s/ould record t/e value of ot/er related counters and c/oose a "ro"er formula accordin# to t/e actual conditions9
$% ,' %' + -uawei !ec.no ogies Proprietar/ Page $0 o* +,
8/11/2019 08 GSM BSS Network KPI (Immediate Assignment Success Rate) Optimization Manual.doc
27/34
GSGSM BSS Network KPI (Immediate Assignment Success Rate) Optimization Manua IN!"RNA#
5Cases of (mmediate Assignment uccessRate &ptimi#ation
1 Case 7@ 0ecrease in Immediate Assi#nment Success Rate Because of
S0CC8 Con#estion Caused ,y Incorrect LAC Settin#
*roblem description
T/e S0CC8 con#estion rate of cell 2 in S7D7D7 confi#uration $as /i#/er t/an 4 :
and t/e immediate assi#nment success rate of t/at cell $as =3 9
Cause analysis and handling
'7( T/e m easurement counters of t/e TC8 and S0CC8 s/o$s t/at t/e traffic volume on
t/e TC8 is lo$: and t /e traffic volume "er cell in ,usy /ours is lo$er t/an 292 Erl /o$ever:
t/ere are many S0CC8 sei*ure re>uests ' 3 2 in ,usy /ours(: t/e traffic volume on t/e
S0CC8 is 7946 Erl: and t/e con#estion rate is /i#/er t/an 4 9
'2( T/e S0CC8 is mainly occu"ied ,y t/e si#nalin# ,efore t/e call is esta,lis/ed:t/e si#nalin# durin# /andover: t/e si#nalin# for location u"date in idle mode: and t/e
s/ort messa#es9
' ( As t/e traffic volume on t/e TC8: t/e num,er of TC8 sei*ure re>uests ' 74(: and
t/e num,er of /andover re>uests '7!6( are all normal: $e infer t/at t/e /i#/ S0CC8
sei*ure rate may ,e caused ,y too fre>uent location u"dates or too many s/ort
messa#es9
'!( T/e LAC of t/e cell is 3?33: ,ut t/e LACs of ot/er cells around t/is cell are all
3?239 After t/e LAC of t/e cell is c/an#ed to 3?23: t/e num,er of S0CC8 sei*ure
re>uests ,ecomes 2=4: t/e traffic volume on t/e S0CC8 ,ecomes 392; Erl: t/e
con#estion rate decreases to 3: and t/e immediate assi#nment success rate reac/es u"
to =? 9
$% ,' %' + -uawei !ec.no ogies Proprietar/ Page $2 o* +,
8/11/2019 08 GSM BSS Network KPI (Immediate Assignment Success Rate) Optimization Manual.doc
28/34
GSGSM BSS Network KPI (Immediate Assignment Success Rate) Optimization Manua IN!"RNA#
1$ Case 2@ S0CC8 Con#estion Caused ,y a Burst of Location ."dates
*roblem descriptionT/e immediate assi#nment success rate $as lo$ in a local net$or%9 Traffic statistics
s/o$ed t/at t/e "ro,lem $as mainly caused ,y S0CC8 con#estion on some sites9
Cause analysis and handling
'7( Traffic statistics s/o$s t/at t/e S0CC8 is occu"ied for 33 to !33 times in ,usy
/ours9 T/e con#ested cells are all in S7D7D7 confi#uration and eac/ cell is confi#ured $it/
ei#/t S0CC8sD49 In normal conditions: 33 to !33 times of S0CC8 sei*ures are
acce"ta,le: ,ut S0CC8 con#estion /a""ens for tens of times in eac/ cell9
'2( Traffic statistics s/o$ t/at most of t/e S0CC8 sei*ures are caused ,y location
u"date9 As most of t/e con#ested BTSs are located in t/e intersection areas of t$o
location areas alon# t/e rail$ay: $e dou,t t/at t/e S0CC8 con#estion may ,e caused ,y
a ,urst of location u"dates9
' ( After c/ec%in# t/e five5minute traffic statistics: $e find t/at most of t/e location
u"dates /a""ened $it/in a certain "eriod of five minutes9 T/e train timeta,le s/o$s t/atfour or five trains /ad "assed $it/in t/at five minutes9 1/en t/e trains "assed: a ,urst of
location u"dates $ere "erformed durin# a s/ort "eriod of time: t/us: t/e con#estion
/a""ened9
'!( +or t/e BTSs located in t/e intersection areas of t$o location areas alon# t/e
rail$ay: it is recommended t/at t/e S0CC8 dynamic assi#nment function ,e ena,led
and ade>uate S0CC8s ,e confi#ured9
1+ Case @ Lo$ Assi#nment Success Rate Because t/e RAC8 Minimum
Access Level Is Set to 3
*roblem description
Su,scri,ers of t/e cells controlled ,y a certain BSC com"lained t/at t/e success
rate of random access $as lo$9
$% ,' %' + -uawei !ec.no ogies Proprietar/ Page $& o* +,
8/11/2019 08 GSM BSS Network KPI (Immediate Assignment Success Rate) Optimization Manual.doc
29/34
GSGSM BSS Network KPI (Immediate Assignment Success Rate) Optimization Manua IN!"RNA#
Cause analysis and handling:
'7( T/e cloc% status of t/e BTSs are normal9
'2( T/e value of "arameter T@ integer 0RAC! Timeslot2 is normal9 By analy*in#t/e data and traffic statistics: $e find t/at t/e "arameter RAC! )in Access +evel
of all t/e cells $it/ lo$ assi#nment success rate is set to 39 T/e immediate
assi#nment success rates of cells $/ose RAC! )in Access +evel are set to 7: :
or ?: /o$ever: are around == 9 Accordin# to t/e "revious data: $e infer t/at t/e
"ro,lem is caused ,y mista%en access9
' ( If RAC! )in Access +evel is set to 3: t/ere is no restriction on t/e random
access If RAC! )in Access +evel is set to 7: a call can access t/e cell only
$/en t/e level is /i#/er t/an Q73= dBm9
In S/antou .nicom: t/e RAC! )in Access +evel of most of t/e cells is set to 3 to
im"rove t/e "a#in# success rate9 T/is causes a #reat num,er of mista%en access
and finally causes lo$ assi#nment access rate9
In addition: t/e "arameter Random Access 9rror Threshold also /as error
restrictions on t/e access si#nals9'!( 1/en RAC! )in Access +evel and Random Access 9rror Threshold of all
t/e cells in module 7 of t/e BSC in S/antou .nicom are set to different values: t/e
results are as follo$s@
1/en Random Access 9rror Threshold and RAC! )in Access +evel are
set to 233 and 7 res"ectively: t/e mean immediate assi#nment success rate of
all t/e cells is =;9= an /our later
1/en Random Access 9rror Threshold and RAC! )in Access +evel are
set to 233 and 3 res"ectively: t/e mean immediate assi#nment success rate of
all t/e cells is =79=2 an /our later
1/en Random Access 9rror Threshold and RAC! )in Access +evel are
set to 743 and 7 res"ectively: t/e mean immediate assi#nment success rate of
all t/e cells is =;92! t/ree /ours later9
After discussin# $it/ t/e customer: $e decide to set Random Access 9rror
$% ,' %' + -uawei !ec.no ogies Proprietar/ Page $3 o* +,
8/11/2019 08 GSM BSS Network KPI (Immediate Assignment Success Rate) Optimization Manual.doc
30/34
GSGSM BSS Network KPI (Immediate Assignment Success Rate) Optimization Manua IN!"RNA#
Threshold and RAC! )in Access +evel of all t/e cells to 743 and
res"ectively9 In t/is $ay: mean immediate assi#nment success rate of all t/e
cells is /i#/er t/an =496 9
1, Case !@ Lo$ Immediate Assi#nment Success Rate in Some Cells
Because of MS Error
*roblem description
T/e "ersonnel on site re"orted t/at t/e immediate assi#nment success rate of some
cells $as lo$9
Cause analysis and handling
'7( As t/e "ro,lem e ists only in some cells: it may ,e caused ,y t/e MS error9
'2( Traffic statistics of t/e cells $it/ t/e "ro,lem s/o$ t/at t/e num,er of lin%
esta,lis/in# failures durin# location u"dates is a""ro imately e>ual to t/e num,er of
times t/at t/e setu" indication timer e "ires: as s/o$n in t/e follo$in# fi#ure9 T/is
indicates t/at t/e S0CC8 setu" failure is mainly caused ,y location u"dates9
' ( T/e si#nalin# of t/e cells $it/ "ro,lem s/o$s t/at #enerally t/e value of TA is
$% ,' %' + -uawei !ec.no ogies Proprietar/ Page +% o* +,
8/11/2019 08 GSM BSS Network KPI (Immediate Assignment Success Rate) Optimization Manual.doc
31/34
8/11/2019 08 GSM BSS Network KPI (Immediate Assignment Success Rate) Optimization Manual.doc
32/34
8/11/2019 08 GSM BSS Network KPI (Immediate Assignment Success Rate) Optimization Manual.doc
33/34
GSGSM BSS Network KPI (Immediate Assignment Success Rate) Optimization Manua IN!"RNA#
in t/e follo$in# fi#ure9
'?( +or a s$a""in# "roJect: c/ec% $/et/er t/e "ro,lem e ists in t/e net$or% ,efore
s$a""in#9 If t/e "ro,lem e isted: t/en $e can infer t/at t/e "ro,lem is mainly
related to t/e MS9
6 &nsite (nformation that Needs to -e
&btained
79 Traffic statistics of t/e net$or% durin# one $ee% ,efore and after t/e "ro,lem
occurred9
- C5=:
'7( All t/e counters of t/e Access Capability )easurement < and Access
Capability )easurement = in - C &verall *erformance )easurement
'2( All t/e counters of Receive uality *erformance )easurement
' ( All t/e counters of t/e DCC! Assignment *erformance )easurement
and TC! Assignment *erformance )easurement in Channel Assignment
*erformance )easurement
'!( All t/e counters of DCC! *erformance )easurement : TC! *erformance
)easurement : and Random Access *erformance )easurement in Cell
*erformance )easurement 9
- CB777:
$% ,' %' + -uawei !ec.no ogies Proprietar/ Page ++ o* +,
8/11/2019 08 GSM BSS Network KPI (Immediate Assignment Success Rate) Optimization Manual.doc
34/34
GSGSM BSS Network KPI (Immediate Assignment Success Rate) Optimization Manua IN!"RNA#
'7( All t/e counters of Access )easurement per - C in - C )easurement
'2( All t/e counters of (nterference -and )easurement per TR, and Receive
uality )easurement per TR, in )R )easurement
' ( All t/e counters of Channel Configuration )easurement per Cell in
Channel )easurement
'!( All t/e counters of K*( )easurement per Cell : (mmediate Assignment
)easurement per Cell : and %lo' Control )easurement per Cell in Call
)easurement 9
29 0ata confi#uration and )MC data o"eration lo#s ,efore and after t/e "ro,lem
occurred9
9 0ata confi#uration file and en#ineerin# "arameters ta,le9
!9 1/et/er t/e net$or% o"timi*ation o"erations: suc/ as antenna adJustment:
fre>uency adJustment: and location area adJustment: are "erformed after t/e "ro,lem
occurred9
?9 Alarms #enerated ,efore and after t/e "ro,lem occurred: includin# commissionin#
alarms9