RACCHfilter.DOC

8/11/2019 RACCHfilter.DOC

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Site

VlizyRadio Communication Division / Mobile Radio

Originator

F. Jarreau

RACCH filtering

Domain :Alcatel 900/1800 BSS

Division :

Rubric :

Type :Distribution codes :

redistribution :

Abstract : the aim of this document is reort on the !A""# filterin$ e%eriment done on

the Armori&ue ro'ect.

Approval

!ame

Signature

!ame

Signature

Alcatel "ile Reference Date #dition age

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S"R : Armori$ue pro%ect

RACCH filtering


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TA&'# O" CO!T#!TS

( )!TROD*CT)O!+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++,

- ASS*MT)O!S++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++,

. ROC#SS++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++,

, )M'#M#!TAT)O!+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

0 CO!C'*S)O!++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

-.1 FF""2F3#F43!5......................................................................................*

-.( S67!27S!A"#..........................................................................................................,

-.+ 2V!A44AA4SS......................................................................................................,


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( )ntroduction+

3he conte%t is the folloin$.

n the deartment 8- :otorola is ;ein$ relaced ;y Alcatel. Alcatel is committed to s ones.

SF! has noticed that the S?""# dro has increased a;o@e the redefined threshold

1.-C for many rural cells. 3his rate can ;e as hi$h as 10 in some cases.

n order to assure a $ood &uality on the S?""# time slot the channel confi$uration is

chan$ed ith the S?""# 3S mo@ed to the B""# fre&uency hen necessary and ossi;le 1

3S dedicated to S?""# no BB# imlementedC. 3his reconfi$uration $a@e $ood results in

most cases ;ut sometimes remains unefficient.

3herefore e tried to use !A""# filterin$ in order to filter out !A""# access that are

considered too far to ;e @alid.

- Assumptions

t as assumed that art of the !A"# messa$es

either ere due to resur$ences.

2r ere surious !A"# #2 access erroneously decoded as !A"# messa$esC

3hose messa$es are deemed to ;e located further aay from the 3"# traffic. 3herefore it

should ;e ossi;le to for;id their access on a distrance criterium.

. rocess


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3he folloin$ rocess as erformed D


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An AE;is trace as erformed.A: lists the e@ents S?""# allocated not used>. 3he su;se&uent 3As ere listed.

?oes the same e@ent ith the same 3Aoccurs on to consecuti@e messa$e or one

out of to

An other cell ith the same BS" andthe same fre&uency as the ser@in$>s B""#

as loosBS" chan$ed.

es

o

A minimum 3A as determined from a co@era$e ma.

A first aro%imation of !A"#G3AGF43! is assumed hi$her than the minimum and loerthan the ma'ority of the 3As for hantom !A"#s.

3he e@ents occurin$ for 3A H !A"#G3AGF43! ere listed. these e@ents are only

3he e@ents occurin$ for 3A H!A"#G3AGF43! are listed. Are thesee@ents are only 4ocation 7date> or @eryshort communications finishin$ ith a call

dro Ies

o

3he !A"#G3AGF43! is

imlemented. ?ecrease !A"#G3AGFilter

!A"#G3AGFilter H radius of the cell

es

3he assumtions are ron$

o


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, )mplementation

3he 9 orst cells of the orst BS" as far as S?""# dro is concerned ere selected D

&TS1!ame SDCCH DRO

CHAUCHE-08510 4,76%

CHAUCHE-18510 2,55%

POUZAUGES-08551 8,55%POUZAUGES-18551 8,50%LES-EPESSES-0970 2,59%

LES-EPESSES-1090 2,49%ST-MICHEL-MERCURE-08502 4,10%ST-MICHEL-MERCURE-18502 1,91%LA-GAUBRETIERE-28523 2,19%

3hey turned out to ;e only lar$e and rural cells some of them ith identified resur$ences.

"onse&uently the folloin$ actions ere ta


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-.( Surious !A"#

Surious !A"# could ;e identified only ith those AE;is traces. @en if !A"# filterin$ould ha@e decreased the henomenon it ould ro;a;ly not ha@e eradicated it. 3herefore it

seems that trou;leEshootin$ remains necessary in case of S?""# dro.

-.+ 2@erall Analysis

1C t has to ;e noted that only lar$e and rural cells are imacted ;y this S?""# dro

increase. e can infer that the introduction of the 5+ B3S has created a zone on the

outs


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(C n order to find a osition the distri;ution of 3A may ha@e ;een analyzed on 5( B3Ss

ith 3:A and on 5+ B3Ss ithout 3:AC. et only 6:11 results ere collected for 5(

B3Ss and they are related only to 3"# measurements.

Conclusion3his e%eriment ena;led to ro@e that !A""# filterin$ $i@es $ood results ;ut remains a

fine tunin$ tool. As far as a $eneral e%lanation is concerned the imressi@e increase of

S?""# dro is concerned deeer in@esti$ation should ;e erformed on cells saed from

5( to 5+ AE;is tracesC or actual measurements of sensiti@ity.


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