GO_NP01_E1_1 GSM Radio Network Planning Principle-96

7/28/2019 GO_NP01_E1_1 GSM Radio Network Planning Principle-96

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GSM Radio network planning principle

ZTE University



Objectives

At the end of this course, you will be able to:Describe the contents of information collectionState capacity planningState coverage planningDescribe steps to notices of site surveyMaster frequency planning and anti-interferencetechnology



Contents

Netwo rk p lann ing inform at ion co l lec t ion Capacity PlanningCoverage Planning

Site layout & SurveyCoverage EmulationFrequency Planning



Overview

Mobile service forecastSubscriber forecast, distribution

Network equipment &

operation profileMSC,BSC,BTSTraffic statistic, quality

City planningCity type, mapPopulationEconomic development planRoad and transport condition

Information Collection

Radio propagation surveyGeographic environmentPlantation

Network traffic distributionIndustrial, commercial, residential

area

Coverage and quality analysisCoverage and quality (DT)Statistic of A, Abis and OMCR

Interference analysisFrequency allocationFrequency scanning test

Analysis and survey



Frequency Other Traffic ModelCapacityCoverage

Limited

frequency

Available

bandwidth

Frequency

resources

Coverage

KPI

Traffic

distributing

Coverage

size

Redundancy

and other

requirements

traffic

distributing

Traffic and

systemcapacity

Data traffic

model

Voice traffic

model

Site

configuration

Propagation

environment

Electronic

map exists ?

Requirement analysis





Contents

Network planning information collectionCapaci ty P lann ing

Coverage Planning




Basic concepts

Traffic volumeTraffic modelErlandCall loss rate

Erlang B table



Erlang B table2% 5%

1 0.020 0.053

2 0.223 0.3813 0.602 0.899

4 1.092 1.525

5 1.657 2.218

6 2.276 2.960

7 2.935 3.738

8 3.627 4.543

9 4.345 5.370

10 5.084 6.21611 5.842 7.076

12 6.615 7.950

13 7.402 8.835

14 8.200 9.730

15 9.010 10.633

16 9.828 11.544

17 10.656 12.461

18 11.491 13.335

19 12.333 14.315

20 13.182 15.249

21 14.036 16.189

22 14.896 17.132

23 15.761 18.080

24 16.631 19.030

25 17.505 19.985



Capacity Planning Procedures

Confirm subscriber number

Site numbers andconfiguration

Traffic distributionratio

Site distribution andtheir latitude and longitude

Reach target of capacity planning

1 2 3 4 5

Network scaleCapacity informationcollection

Site layoutTraffic distributionanalysis

Site type andnumber

Capacity Planning



Information collection

Network type: GSM900, DCS1800, dual-band network or WLL network System capacity requirement. No of subscriber and thetraffic?Traffic model of the voice service?Equipment type: V2/V3? Model? Indoor or outdoor? DPCTapplied in V3 or not?Data service required? EDGE TRX? Data servicepenetration rate? Traffic model of data service?

Frequency resource range ? Is there frequency that areprohibited? Maximum site configuration ?Forecast and investigation traffic density and define trafficdistribution ratio.



Traffic density distribution

Traffic distribution analysis is to categorize the planningarea into areas of different service levels based onforecast and survey of traffic density distribution

● how many phases and what is the ratio of

subscribers in each phase

● what is the planning area range and the

traffic distributing ratio in DU/MU/SU/RU.

●Provide existing sites and their configuration and performance statistics

report data

1

41%

2

26%

3

15%

4

11%

5

7%



Service level by radio propagation environment

Area Topographic features

Denseurban

Average height of surrounding buildings is more than 30 metres (over 10 storey)and average distance between buildings is 10-20 metres. Usually the buildingsare crowded around the site with the height of 10-20 stories and the ambientroads are not considerably wide.

urban

Average height of surrounding buildings is about 15-30 metres (5-9 storey) andaverage distance between buildings is 10-20 metres. The buildings are evenlydistributed around the site. Mostly are below 9 stories and some are over 9stories and the ambient roads are not considerably wide.

suburb

Average height of surrounding buildings is about 10-15 metres (3-5 storey) andaverage distance between buildings is 30-50 metres. The buildings are evenlydistributed around the site. Mostly are 3-4 stories and some are over 4 stories.

Roads around are wide.

rural Average height of surrounding buildings is below 10 metres. They are dispersedand mainly are 1-2 storey high. There are spacious space between.





Number of BTS sites-1

No. of BTS for capacity limited areaMaximum site type by frequency reuse patternTraffic per site by traffic model, Erlang-B table

Total number of BTS: Total traffic / single sitetraffic



Number of BTS sites-2

No. of BTS for coverage limited areaTotal area / single site coverage (according to servicelevel)Cell traffic = Cell coverage * traffic density

TCH number (Erlang-B table)SDCCH number TRX number



Start

Frequency resources

Capacity of each cell

Capacity per siteSite configuration& number

Frequency reusepattern

MaximumSite type

Channel planning& data service

Erlang B table

Traffic model

Site configuration

Traffic &distribution

Network Scale Coverage Planning

Site type and number



No of SDCCH

Suppose SDCCH average process time is 3s Location updatingprocess is 9s,BHCA=2

The traffic of SDCCH per subscriber is:

(3×2 + 9) / 3600 = 0.0042 Erlang

4SDCCH call loss=2% can support 1.092Erlang (1.092 / 0.0042 = 260sub) ×0.025 Erlang = 6.5Erlang

look up in Erlang-B call loss=2% 6.5Erlang need 12TCH(2TRX)

8SDCCH call loss=2% can support 3.627Erlang

(3.627 / 0.0042 = 863sub) ×0.025 Erlang = 21.6ErlangLook up in Erlang-B call loss=2% 21.6Erlang need 30TCH(4TRX)





LA planning

LA border Paging capacity in LAPaging capacity calculationInfluence by Short message



LA border

Avoid dense city with high traffic area Avoid area with high mobility of subscribersCross the road slantwiseConsider traffic expansion



Paging capacity

IMSI/TMSISecond paging local paging global paging Paging group

(BS-AG-BLK-RES)

(BS_PA_MFRAMS)Paging blocks/ per second = 9-AGB /0.2354Paging number / per paging block : B = 2 or 4





Influence by short message

3/per sub/per day30% retransmitConvergence factor:0.12

Subscriber in LA:100000SM number in busy hour

100000×3×0.12×(1+30%)=46800Consider holiday case: 8 times



CoveragePlanning

CapacityPlanning

NetworkScale

Summary

Capacity planning is just an initial plan, Add or reduce sitesbased on radiocoverage planningand analysis.Capacity planning isa repeated, gradualprocess helping todecide site number and type.



Contents

Network planning information collectionCapacity PlanningCov erage Plann ing




Coverage Planning flow

Set parametersEstimatedcoverage radius of each site

Allowable max pathloss

Information of sitedistribution ,latitude & longitude

of sites

Target of coverage

1 2 3 4 5

Network scaleNetwork parameter

Site layout &coverage emulationLink budget Coverage radius

estimate





2

Link Budget

Link budget

Definition:Link budget is the calculation of loss and gains on one

communication link.

Target:Maximum power of the site, avoid invalid downlinkcoverage, reduce interference and system noise.

Allowable maximum indoor & outdoor path loss of uplinkand downlink Uplink Downlink



PA

Feeder loss Transmissionloss

Antenna gain Penetration loss

Site sensitivity

Fading margin

Body lossMS power

Link budget





Link budget-Equipments

MS transmission power is showed as follows

Power class

GSM 900Nominal

Maximum outputpower

DCS 1800Nominal

Maximum outputpower

PCS 1900Nominal

Maximum outputpower

1 1 W (30 dBm) 1 W (30 dBm)

2 8 W (39 dBm) 0.25 W (24 dBm) 0.25 W (24 dBm)

3 5 W (37 dBm) 4 W (36 dBm) 2 W (33 dBm)

4 2 W (33 dBm)

5 0.8 W (29 dBm)



Link budget-EquipmentsSeries Modulation Transmission power Reception

sensibilityBiggest site

BTSV3

B8018GMSK 60 W 47.78 dBm

-112 dBm S18/18/188PSK 31 W 45 dBm

B8112GMSK 60 W 47.78 dBm

-112 dBm S12/12/128PSK 31 W 45 dBm

M8202GMSK 30 W 44.78 dBm

-110 dBm S2/2/2 or O68PSK 20 W 43 dBm

BTSV2

GMSK 40W 46 dBm -110 dBm S12/12/12

GMSK 80W 49 dBm -110 dBm S6/6/6

8PSK 30W 44.78 dBm -110 dBm S12/12/12

(EDGE) GMSK 60W 47.7 dBm -110 dBm S12/12/12

OB06 GMSK 40W 46 dBm -110 dBm S6/6/6

BS30 GMSK 40W 46 dBm -110 dBm S2/2/2

BS21GMSK 40W 46 dBm -110 dBm S2/2/2

GMSK 80W 49 dBm -112 dBm S1/1/1



Link budget-Loss

Path lossBody lossVehicle lossPlantation lossBuilding penetration lossFeeder and connector lossCombining anddistributing unit loss



Link budget-Loss

Path lossRadio wave loss caused by the transmission distance.

Body lossVoice service, body loss 3 dBData service, 0dB.

Vehicle lossUsually it is 8~10dB.



Link budget-Loss

Plantation lossInside the forest, the loss of 900MHz is 0.2dB/m; theloss of 1800MHz is 0.3dB/mThrough forest or diffraction, the loss is 20dB/dec

Forest around the antenna and the antenna is lower than the forest, around 10dB

Building penetration loss Averagely it’s 10 – 20 dB relying on building materialand thickness.



Link budget-Loss

Feeder cable loss

Type loss dB/100m

900M 1800/1900M

1/2 soft jumper 7.22 11.3

7/8 feeder 3.89 6.15

15/8 feeder 2.34 3.84







Link budget-Margin

Fast fading & deterioration storagewalking 2.0--5.0dBfast moving 0dBIn GSM system, fast fading for voice and data service is

supposed to be 3dB.Interference margin

The interference margin is generally supposed to be3dB.



Link budget-Margin

Slow fading (shadow fading) marginshadow fading is based on

standard deviation

margin coverage probability.

slow fading standard deviation is related to propagation

condition. In cities, it’s about 8~10 dB, while in suburbs

or rural areas 6 8dB.Marginal coverage

probability(%)70 75 80 85 90 95 98

Slow fading margin/dB 0.53σ 0.68σ 0.85σ 1.04σ 1.29σ 1.65σ 2.06σ



Link budget

Parameter Symbol

MS transmitting power A

Body loss B

Building loss C

MS reception sensibility D

MS antenna gain E

TMA gain FDiversity gain G

Feeder loss H

Combiner/divider unitloss

I

Fast fading margin J

Slow fading margin K

Noise margin L

Path loss indoor M=A-B-C-D+E+F+G-H-I-J-K-L

Path loss outdoor N=M+C

Path loss difference

between uplink and

downlink is 3-5dB



3

Coverageradius estimate

Estimate coverage radius

Maximum allowable path loss

Propagation modelOkumura-Hata model

Cost231-Hata model

Universal model

Cost231-Walfish-Ikegami model

Estimatecoverageradius

Max allowable loss Propagation model selection



4 Site layout &coverage emulation

Sitedistribution

Electronic mapPlanning area sizePlanning site number Link budgetradius estimate

Distribution mapDistribution infoLatitude & longitude

Site layout & emulation

****Input Output



Coverage &emulation

****Input Output

Electronic mapPlanning map

latitude & longitude Antenna height/direction angle Antenna selectionPropagation modelLink budgetExisting network data

Site distribution mapSite coverage effect mapHeight info mapExisting network coverage mapCoverage probability statistics table

4 Site layout &coverage emulation



5Network scale

Coverageplanning

Capacityplanning

Networkscale

Summary





Site layout & survey procedure

coverage planning

+ capacity planning

=>network scale

Distribute site on Mapinfo

or PLANET/EET E-map,

decide site theoretic

location, latitude &

longitude and other para of

sites

Based on theoretic location of

sites, make sites survey.

Confirm site location, site type &

location, antenna type, height,

direction angle, downtilt, CDU,

TTA and feeder etc.



Site survey

Optical measurementConstruction environment and naturalenvironment

Frequency spectrum measurementElectromagnetism environment

Site investigateInstallation condition of antenna and equipmentPower and transmission supply





Site layout & survey

When select site location, take the following aspects into

considerationPrevious Network conditionPopulation distribution and habitsCity layout and distributionMain streets and traffic volume

Natural environment such as Hills, lakes, rivers and coastlineGrowing trend

Select high traffic area and

dense population area

population

Traffic distribution

Customer mobility trend

Principles of site selection

Surrounding environment

Signaling transmission

quality

Careful select high hills, radar,

radio station, gas station, forest

and power plant





CDU

Feeder design

Antenna

Height, directionFrequency range,

gainPolarization3dB beam widthDown tilt

To increasereceiving sensitivity of BTS

TMA Feeder

Antenna and feeder



City site

Suburbsite

Antenna selection

Site in citySelect directional antenna with horizontal 3dB bandwidth of 6065°Select medium gain antenna of about 15dBiBest to select antenna with electrical tiltdown of 3 6°

Recommend dual-polarized antennaSite in suburb

Select direction antenna with horizontal 3dB bandwidth of 65°or 90°Generally select medium or high gain antenna 15~18dBiPreset downtilt or not based on actual conditionSelect dual polarized or vertical polarized antenna



City site

Suburbsite

Antenna selection

Site in rural areaSelect directional antenna of 90° 120°or omni antennaHigh gain of directional antenna 16 18dBi Generally don’t select downtilt antenna. For high sites, zero fillingantenna is the best choice.

Vertical polarized antenna is recommendedRoad site

Select narrow-beam, high gain directional antenna. 8-shapeantenna, omni antenna or deformation omni antenna based onactual conditionGenerally don’t select downtilt antenna because road site hashigher requirements to coverage distance.Vertical polarized antenna is recommended.



Principle for antenna height

Antenna of different cell of the same site can be differentdue to installation conveniences or cell planningrequirements.For flat urban area, height of antenna is around 25m.For suburbs, antenna height can be elevated to 40m.

Antenna can not be too highReduce coverage level near the antenna especially for omni

antennaEasy cause problems affecting network quality like over coverage,

co-channel interference or adjacent-channel interference.





Principles of antenna tiltdown

Antenna tiltdown is the basic method to enhancefrequency reuse ability.Control coverage and reduce interferenceElectrical or mechanical tiltdown.Mechanical tiltdown angle < 15°



Space diversity distance

Distance between two receiving antenna is 12 18λwhenantenna is diversified by space.Generally distance between diversity antenna is 0.11 timesof the antenna height.To achieve the same effect, distance of vertical diversitymust be 5 to 6 times of horizontal diversity.To reduce the interaction of the two antennas, horizontaldistance of diversity antenna should be over 3 m





Coverageemulation

****Input Output

Coverage emulation

Electronic mapPlanning areaLatitude & longitude of sites

Antenna height & direction angel Antenna model

Link budgetExisting network data

Sites distribution map

Site coverage effect map

Height information map

Existing network

coverage map

Coverage rate statistics

table



Contents

Network planning information collectionCapacity PlanningCoverage Planning

Site layout & SurveyCoverage EmulationFrequ enc y Plann ing



GSM working frequency band

GSM900Uplink 890 915 MHzDownlink 935 960 MHzduplex separation is 45MHzcarrier frequency separation is200KHzEGSMUplink 880 890 MHzDownlink 935 935 MHzduplex separation is 45MHz carrier frequency separation is200KHz

DCS1800Uplink 1710 1785 MHzDownlink 1805 1880 MHzduplex separation is 95MHz carrier frequency separation is200KHz

P-GSM900Fl (n) = 890 + 0.2 n MHz

Fu (n) = Fl(n) + 45 MHz 1 n

124n stands for ARFCNE-GSM900Fl (n) = 890 + 0.2 (n-1024) 975 n 1023Fu (n) = Fl(n) + 45 MHz 0 n

124DCS1800Fl (n) = 1710.2 + 0.2 (n-512) MHzFu (n) = Fl(n) + 95 MHz 512 n

885

ARFCN





Frequency reuse distance

The following equation is used to estimate frequency reusedistance:

D = 3 N * R

D —— frequency reuse distanceR —— cell radiusN - frequency reuse factor.



Definition of C/I and C/A

Co-channel Interference C/I

C/I refers to the interference of another cell using thesame frequency to the current cell. The ratio of carrier to interference is called C/I.

GSM specification regulates that C/I >9dB. Inimplementing, it requires C/I>12dB.

Adjacent channel interference C/A

C/A refers to interference of adjacent channel to thecurrent channel. The ratio is called C/A. The GSMspecification regulates that C/A>-9dB.



Calculation of C/I

Where, Pown_cell is the signal strength of currentcell; Pi_BCCH is BCCH signal strength of interferingcell i measured by MS.







l l



Multiple reuse pattern MRP

BCCH can use 4 3 or higher reuse coefficient toensure the BCCH quality, while the TCH will userelatively dense reuse mode.The division of BCCH and TCH layer frequencybands reduces the planning workload andfacilitate the layered planning.Reserve some frequency for the micro cell.Simplify the configuration of BA tables

The relative independence of the BCCH and TCHlayers facilitates the maintenance and expansionof each layer.

MRP



TCH2

FRF=6

BCCH FRF=12

TCH1 FRF=9

For MicrocellFRF: Frequency reuse factor

Bandwidth=6 MHz

MRP



A li i f MRP



Application of MRP

China mobile: MRPFrequency bandwidth: 7.2MHz

AFN: 60 95 Divide 36 carrier frequencies into 4 group as per

12/9/8/7

Channeltype

Logic channel TCH1 servicechannel

TCH2 servicechannel

TC3 servicechannel

Channelnumber

60 61 62 63 64 6566 67 68 69 70 71

72 73 74 75 76 7778 79 80

81 82 83 84 8586 87 88

89 90 91 9293 94 95









IUO



IUO

IUO has the same network structure as ordinaryconcentric, consisting of Overlay and Underlay.Underlay and Overlay of IUO both use the sametransmitting power.IUO adopts a handover algorithm based on C/IIt’s very suitable for absorbing traffic inside building.



TCH frequency plan



TCH frequency plan

The frequency in same site can not be reusedIn same cell, the frequency distance between BCCH andTCH is at least 400khzFrequency can not be reused in its directly adjacent sites if it is not 1*3 patternOpposite cells should not be co-channel and avoidadjacent channel.High hill in the middle shall not be considered asneighboring sites while broad water in the middle shall beconsidered as neighboring sites.

Avoid to set same BSIC to BCCH with same frequency



Attention



Attention

Reserve frequencies for

Test in propagation,Replacement frequency in the interference test,Micro cell frequency in hot spot area.

Generally BCCH should use higher continuous frequencies.

Allocate frequency based on different areas. Allocate frequency for sites in different areas such as urban,suburb and rural.Focus should be put on cities to avoid interference.Make planning in urban areas before suburbs and rural areas.Divide urban area into small areas if there are many sites.

Check manually after frequency assignment via automatic frequencyplanning.



Discontinuous transmit (DTX)



Discontinuous transmit (DTX)

DTX encodes the voice at 13kbit/s during thevoice active period, it encodes the comfortnoise at 500bit/s during the quiet period.

DTX



DTX

DTX contributes very little to the interferenceduring the quiet period, its power can beregarded as 0 (inactive state).

Suppose the DTX active factor is , then thegain

log10log10log10)(/ I C I C dB I C





FH



FH

Frequency hopping is to avoid externalinterference. In other words, it is to prevent or greatly reduce co-channel interference andfrequency selective fading effect by

converting frequencies to an extent thatinterference cannot catch up with.Baseband and synthesized FH

ParametersHSN hopping sequence number MAIO mobile assignment index offset





Interference diversity gain



Interference diversity gain

In consideration of the above figure, suppose the MS talks byusing fk at the time t, in this case, the probability of theinterfered cell fk is

mn

I C

pI C

dB I C log10log10log10)(/

nmC C p mnmn //11

Hopping set MA },...,,,{ 321 n f f f f ,

TRX number m (m n)

Interfering cell









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GO_NP01_E1_1 GSM Radio Network Planning Principle-96