33623428 GSM Cell Planning and Optimization

8/3/2019 33623428 GSM Cell Planning and Optimization

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By Sumantri Pramudiyanto (+6281703544310)

Jakarta, April 7th , 2009

GSM Cell Planning and Optimization

Study Case : Sragen Area

Materi berikut merupakan open content, bersifat free utk didistribusikan


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Content

y Cell Planning Process

y Idle Mode Operation

y BSS Parameter

y RF Optimization flow charty Study Cases of RF Optimization


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Cell Planning Process

y Cell planning can be described briefly as all the activities involved in determiningwhich sites will be used for the radio equipment, which equipment will be used andhow theequipment will be configured


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Traffic and coverage Analysisy Collecting required data

y Making discussion with the client to know their demand.

y Analyzing traffic and coverage

Required data :

Geography data

Demography data Data of around network

Available frequency

Number of customer which

wish to cover

Customer demand :

GOS 2%

95 % Indoor coverage

(C/I > 12 db) > 95%


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Nominal Cell Plan - Dimensioning (2)y From the geographic data we can determine Erlang distribution by density in each

cluster.

y

The next step, we can calculate the number of required sites depend on traffic.y Using erlang B table we can count number ofsites for cluster sragen tengah (GOS 2%, 1585.85

Erlang) 1586 TS ~ 227 TRXy Sragen tengah locate in center of town and has high traffic we use configuration 5/5/5 so the

number ofsites required in this cluster :227/15 TRX = 15 Sites

y With thesame way we can calculate number ofsites for the others cluster:

SragenTimur = 9 sites (Config 4/4/4)Sragen Barat = 12 sites (Config 4/4/4)Sragen Utara = 9 sites (Config 4/4/4)


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Nominal Cell Plan Link Budgety Link Budget Calculation is required to achievesystem balance between uplink and downlink

signal.

y Output from system balance is a cell size in every sites.

y We can calculate coverage area per sites in suburban and rural cluster by equation L = k x R2

Lsitesuburban = 1.95 x (1.865)2 = 6.78 km2

Lsite rural = 1.95 x (2.67)2 = 13.90 km2

yThe next step, calculating number ofsites related to coverage.

Choose the biggest one

Link Budget


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Nominal Cell Plan - Result

Sragen Utara

Sragen Timur

Sragen Tengah

Sragen Barat


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Survey

y Survey is required to ensure whether the nominal cell position canbe realized or not ?

y In general, The RF Team should give alternative nominal or informedSAR ( 300m) to survey team, in case the nominal cannot berealized.

y Thesurvey team should take the panoramic photo around thenominal (0-360 degree), and report to the RF team if appearobstacle around the nominal.

y Panoramic photo used to determine coverage target/azimuth

y Survey team also need to survey : road to nominal, electricity, spacefor equipment.


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Detail Planningy All of nominal coordinates must be fixed in detail planning phase.

y Scope of works in Detail Planning :y Frequency Planning

y Parameter Planning (BSIC, MAList, MAIO, HSN, etc)

y Adjacency planning

y The main key in conducting frequency planning is avoiding co-channel and adjacent interference.

y For TCH Frequency planning, we able to apply SFH or Basebandhopping in order to reduce the interference.


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Detail Planning Frequencies Allocation

y SFH Pattern 1x1 will be applied in this implementation

y Number of Malist frequencies can be calculated by using equation :

y Maximum configuration for thesites 5/5/5, so that number of required

frequencies :Nfreqs/site = (12 3 ) x 2 + 3.2 = 24 Frequencies

FL =

NTRX

# HoppersX 100%

3 sectors with 24 hopping frequencies :

-TCH = 3 TRXs FL = (3/24)*100% = 12,5%

-TCH = 4 TRXs FL = (4/24)*100% = 16,67%


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Detail Planning Frequencies Allocation

MAIO = 0 8 16

MAIO Step = 2

SFH Allocation untill configuration 5/5/5


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Detail Planning HSN Planning

Drivetest for QOD Program.ppt / 24.04.2008 /

VS

y

HSN used to the parameter that differentiates the hopping algorithmbetween two cells having thesame MAList.

y We can choose best pairs HSN to reduce collision frequenciesbetween server and adjacent.


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Detail Planning Coverage Result

Coverageediction Sragen Kot

Coverage

ediction Sragen Uta

Coverageediction Sragen Tim

Coverageediction Sragen Bar

NCC = 4,5

NCC = 2,3

NCC = 0,1

NCC = 5,6


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Detail Planning Interference Prediction

C/I Sragen Kota C/I Sragen Barat

C/I Sragen Timur

/I Sragen Utara


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Installation and System Tuning

y After Installation done, the installation team need to conductcommisioning (VSWR Measurement, check hardware installation )

y The Drive test team also need to verify whether the BTS servingtarget correctly or not

y

Then, AcceptanceTest Procedure is conducted to check how wellthe KPI meets the demand.

y PreLaunch Optimization performed to achieve the KPITarget fornew site or TRX expansion.


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IDLE MODE OPERATION

Normal Cell Selection

Search all the RF channels , take samples during 3-5 s and

calculate averages. And put them in ascending order with respect to

signal level. Then tune to the strongest RF channel.

Search for the frequency correction burst in that

carrier in order to varify if it is a BCCH carrier

Camp on the cell

Try to synchronize to the carrier and read

the BCCH data.

Is it a BCCH

carrier?

Is it a correct

PLMN ?

Is the cell barred?

Is C1>0

Tune to the next highest

RF channel which is not

tried before

No

No

NoNo

Yes

Yes

Yes

Yes

C1 = (A - Max(B,0))

A = Received Level Average -

p1B = p2 - Maximum RF Output

Power of the Mobile Station

p1 = rxLevelAccessMin

Min. received level at the

MS required for access to

the system

p2 = msTxPowerMaxCCHMax.

Tx power level an MS may

use when accessing the

system


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Cell Reselection

C1 + cellReselectOffset - temporaryOffset*H(penaltyTime-T) T < = penaltyTime

C2 =

C1 + cellReselectOffset . T > penaltyTime

1 when T < = penaltyTime

H(x) =

0 when T > penaltyTime


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Cell Reselection Histerysis


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BSS Parameter (2)Handover Parameter

y HOLTHLVDL/UL(0-63) defines the receivesignal level threshold on the downlink /uplink for inter-cell

level handover decision.

y HOLTHQUDL/UL(0-7) defines the receivesignal quality threshold on the downlink/uplink for inter-cellquality handover decision

Adjacent Parameter

y RXLEVMIN

the

minimum receivedsignal l

evel th

eadjac

ent c

ell mu

st provid

eto b

eregard

ed a

sasuitabl

etarget cell for handover

y HOM Handover margin for better cell

y LEVHOM parameter defines the handover margin for handovers due to uplink level or downlink level

y QUALLEVHOM this parameter defines the handover margin for handovers due to uplink quality ordownlink quality


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RF Optimization Flow Chart

Start

Identify KPIFormula

Identify the problems

SDSRProblems ?

CheckTRX

Quality

CheckAlarm

CheckInterference

Check all otherscause (Radio link

Failure, T200,Transcoder) from

statisticsHOSR

Problems ?

CheckSDCCHBlocking

CheckTCH

Blocking

Check Alarm

Check co-channel and

co-BSIC

CheckInterference

CheckNeighborR

elation

CheckHandoverFailure Per

Cause

Check

HandoverParameter

DCR Problems

CheckTRX

Quality

Check Alarm

Check co-channel and

co-BSIC

Check TA

CheckInterferenceproblems

Check Malist,MAIO and

HSN

Checkmeasurementfrom statistics

Take Actionlist

Y

Y


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Conclusion

y Every New Network need good plan for avoid problems thatwill be arise.

y Commonly there aresixstep in conducting planning.

y

The most critical problems in performing cell planningprocess is interference.

y the New Sites onair need to be optimized to achieve the KPI

y PreLaunch Optimization is done for new sites on air or

expansion sites.

33623428 GSM Cell Planning and Optimization

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