WPO-07 WCDMA Scale Estimation-90

7/27/2019 WPO-07 WCDMA Scale Estimation-90

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WCDMA Scale Estimation

ZTE University



Overview

The main task of scale estimation is to make an initialestimation to the network configuration, and determine theinitial network components numbers based on the plannednetwork coverage, capacity and quality requirement.WCDMA scale estimation need to comprehensively consider all the factors like network coverage, capacity, quality, etc., andfind the best balance---from the soft capacity property of WCDMA systemThe difficulty of WCDMA scale estimation is to handle thecapacity requirement of both voice and data services — challenge from hybrid service QoS

System coverage

System capacity

Optimization & Adjustment

Investment for network building



investigation

analysis

simulation

Modeling

survey

Requirementanalysis

scaleestimation

Site survey and

design

Transmittingmodel test

Transmittingmode

correction

Out

put planning report

Networksimulation

Network Planning Process

Detailedplanning

scale estimation is an important

stagefor the pre-planning of WCDMA

radio network

Position of Scale Estimation in RadioNetwork Planning Process



Estimation Based on Coverage and Capacity

Determine the number of Node B according to therequirement of coverageForward coverage, reverse coverage →cell coverageradiusCalculate the required Node B number

Determine the required number of Node B accordingto capacity

Forward capacity, reverse capacity →cell capacityCalculate the required Node B number

Select the bigger of the two



Basic Ideas for WCDMA Scale Estimation



Contents

Introduction to WCDMA Scale Estimation

Method for WCDMA Scale Estimation

Case Study of WCDMA Scale Estimation



Simply speaking, link budget is the calculation to all kinds of loss and gain on acommunication link.Definition through and investigation and analysis to all the factors of forwardand reverse signal transmission in the system, the maximum allowedtransmission loss on the link with the premise of keeping a certaincommunication quality will be obtained.

PA

able lossTransmission

loss

Gain ofantenna

Penetrationloss

BSsensitivity

Shadowmargin

Human lossUE power

Link Budge and Models



Parameters Symbol computationTransmitter power A

Gain of transmission antenna BHuman loss at transmission end C

Feeder loss at transmission end DEffective transmission power at

transmission endE= A +B -C-D

Environmental thermal noise FCoefficient of receiver noise G

Service bit rate HGain of processing I = 10 * LOG( 3840 / H )

Eb/No JReceiver sensitivity K = F + G + J – I

Gain of receiver antenna LFeeder loss of receiver MHuman loss of receiver N

Interference margin OShadow fading margin P

Gain of soft handover QMargin of power control R

Penetration loss S

Maximum allowed path loss T = F – K + L - M – N – O – P + Q - R -S

Basic Process of Link BudgetTransmissionend

receiving end

margin



Link Budget Model

UPLINK

CS12.2K

CS64K

PS64K

PS128K

PS384K

HSUPA

TX

Tx Power [dBm] 21.00 21.00 21.00 21.00 21.00 24.00Antenna Gain

[dBi] 0.00 0.00 0.00 0.00 0.00 2.00

Body Loss [dB] 3.00 0.00 0.00 0.00 0.00 0.00

Feeder Loss

[dB]0.00 0.00 0.00 0.00 0.00 0.00

EIRP [dBm] 18.00 21.00 21.00 21.00 21.00 25.59



Link Budget

RX

Thermal Noise Density [dMm/HZ] -174.00 -174.00 -174.00 -174.00 -174.00 -174.00

Thermal Noise [dBm] -108.16 -108.16 -108.16 -108.16 -108.16 -108.16

Receiver Noise Figure [dB] 1.80 1.80 1.80 1.80 1.80 1.80

Receiver Noise [dBm] -106.36 -106.36 -106.36 -106.36 -106.36 -106.36

Bit Rate [kbit/s] 12.2 64 64 128 384 200

Process Gain [dB] 24.98 17.78 17.78 14.77 10.00

-13.00Required Eb/No [dB] 4.20 2.70 1.60 1.10 0.60

Receiver Sensitivity [dBm] -127.14 -121.44 -122.54 -120.03 -115.76 -119.36

Interference Margin [dB] 3.01 3.01 3.01 3.01 3.01 3.01

Antenna Gain [dBi] 18.00 18.00 18.00 18.00 18.00 18.00

Feeder Loss [dB] 2.80 2.80 2.80 2.80 2.80 2.80

Body Loss [dB] 0.00 0.00 0.00 0.00 0.00 0.00



Link Budget

Margin

Power control headroom [dB] 2.00 2.00 2.00 2.00 2.00 2.00

Soft Handover Gain [dB] 3.00 3.00 3.00 3.00 3.00 3.00

Shadow Fading Margin [dB] 8.70 8.70 8.70 8.70 8.70 8.70

Penetration Loss [dB] 18.00 18.00 18.00 18.00 18.00 18.00

Other

TMA gain [dB] 0.00 0.00 0.00 0.00 0.00 0.00

RRU gain [dB] 0.00 0.00 0.00 0.00 0.00 0.00

4 Rx diversity gain [dB] 0.00 0.00 0.00 0.00 0.00 0.00

TX diversity gain [dB] 0.00 0.00 0.00 0.00 0.00 0.00

Max Allowable Outdoor Path Loss [dB] 149.63 146.93 148.03 145.52 141.25 149.44

Outdoor Coverage Cell Raius [m] 2.17 1.82 1.95 1.66 1.25 2.14

Max Allowable Indoor Path Loss [dB] 131.63 128.93 130.03 127.52 123.25 131.44

Indoor Coverage Cell Raius [m] 0.67 0.56 0.60 0.51 0.39 0.66

Cell Radius [km] 0.56



Power at Transmission End

UE transmission power 3GPP 25.101 specified 4 power levels of UE

Power ClassNominal maximum

output power Tolerance

1 +33 dBm +1/-3 dB

2 +27 dBm +1/-3 dB

3 +24 dBm +1/-3 dB

4 +21 dBm ± 2 dB

Data card

Voice terminal



Power at Transmission End

Transmission power of Node BNode B power resources are shared by businesschannel and public channel.To avoid the over occupation of Node B power

resource by single user, the maximum transmissionpower of each channel need to the limited. Channelpower allocation will have direct effect to thedownlink estimation result.

CS12.2 CS64 PS64 PS128 PS384 CPICH

Max transmission powerof Node B

33dBm 33dBm 33dBm 35dBm 38dBm 33dBm

Transmission power of downlink channel (20W)



Receiver sensitivity

Sensitivity of BS receiver is one of the most important indicator for theBS receiving capability, which means the minimum required electricitylevel for receiver to correctly modulate the signal without anyinterference.

Electricity level of signal Thermal noise BS noise coefficientEb/N0 PGTherefore , BS sensitivity is Sensitivity = kTB + NF + Eb/No – PG



Sensitivity for Service Receiving

Sensitivity for Service ReceivingFor empty load sensitivity = kTB + NF + Eb/No – PGWhile loaded sensitivity = kTB + NF + Eb/No – PG + NR- kT: Electricity level of thermal noise dBm/Hz- B: WCDMA frequency bandwidth- NF: Noise coefficient dB

- Eb/No : the required bit S/N dB to meet quality requirement and demodulation- PG: Processing gain dB- NR: Noise rise/interference margin dB

Uplink/downlink demodulation of different services require

different Eb/N0 value and processing gain, thus their sensitivities are also different.



Thermal Noise

Spectral density of thermal noise power inenvironmentN=KTB/B=KTK=1.380650*10E-23 Boltzmann constant

T= Absolute temperature =Centigrade+273.15 B= Receiver bandwidthKT is generally-174dBm/HzThermal noise power Spectral density of thermalnoise power 10log(3840000 -108.157



Noise coefficient

Noise coefficientNoise coefficient is a systematical concept, which isgenerally used to measure the system deteriorationfrom signal input to signal output, and defined as theratio of input S/N to output S/N:

BS 3 5dBPhone 7 8dB



Quality Factor

Eb/N0 Bit energy/Density of noise spectrumEb/N0 refers to the quality factor of service demodulation atreceiver, and related to service type, mobility speed,encoding/decoding algorithm, antenna diversity, power control,multi-path environment, and so on. It is the reflection of thedemodulation capability of the equipment.Eb/ No = Ec/Io + Frequency spreading gain

Powerspectrum

RequiredEb/No

UE1 NoiseUE 2UE 3



Processing Gain

PG = Chip speed/Bit rate (PG W/R)PG is different for different services, thus thecoverage radius are also differentPG of voice service 10log(3840/12.2)=24.97971

PG = 25dB

Voice 12.2 kbps Data 64 kbps Data 384 kbps BTS

PG = 18dB

PG = 10dB



Noise Rise

Noise rise/interference margin (Noise Rise)WCDMA system is a self interference system, whose coverage isclosely related to capacity, and referred as noise rise in link budget.The bigger the load is allowed in system, the larger the required noiserise will be, and the smaller the coverage will be . If coverage is limited,please use a smaller noise rise; but if capacity is limited, please use a

larger noise rise.Typical value 1~3dB, correspondent to a load of 20~50%(uplink)

Noise rise is the breakthrough pointfor the analysis of capacity’s effect

to coverage



Noise Rise

Noise rise/interference margin (Noise Rise)Noise rise= -10*log(1- η), η is the cell load. The cell respiration we are usually talking is indicated like this in linkbudget. When UEs in the cell increases, load will be increased, thecorrespondent noise rise will also be increased, thus the maximumallowed path loss of the cell will be reduced, and so will be the

coverage. During network planning, the uplink load for dense urbanand urban areas is usually designed as 50 to correspond to the 3dbnoise rise; while for suburban and rural areas with less users, theuplink load is designed as to correspond to 1.55db noise rise.

DU MU SU RU Highway

Uplink load designed for the cell 50% 50% 40% 30% 30%

Correspondent interference margin 3dB 3dB 2.2dB 1.5dB 1.5dB



Loss in Radio Transmission

Human lossTransmission loss

Feeder loss

Penetration loss

Vehicle loss

BS comprehensive loss at connector, combiner, etc.

Penetration through buildingsPenetration through vehicals




Human lossRefers to the loss caused by signal block and absorptionwhen phone is held quite near the human body. Humanloss depends on the position of the phone to humanbody. For handheld phone, when it is near the waist of

shoulder of the user, field strength of the received signalwill respectively be 4~7dB and 1~2dB smaller whenantenna is moved several bands farther from humanbody During the link budget of voice service, its value isusually 3dB; while in the link budget of data service withdata card, the value is usually set as 0dB

CS12.2 CS64AND PS

Human loss 3dB 0




Feeder lossUse 7/8 feeder when its length is lessthan 50m and 5/4 feeder when the lengthis larger than 50m. When RRU is fixed onthe tower and close to the antenna, use1/2 feeder if its length is less than 10m;

Generally, length of the feeder is <50m,and 7/8 will be used. For 2G frequencyband, the feeder loss for each 100m willbe around 6dB. Loss of the whole feeder,including those from equipment top to theantenna connector, jumper cable and

connector, is about 3-4dB.

Type 2GHz loss

Unit inch dB@100m

Standard 1/2” 12.3

Standard 7/8” 5.75

Super-soft 1/2” 16.4



Small-loss 1/2” 10.5






Penetration lossRefers to the reduction of the radio wave when it passes through the outer structure of the buildings, which is also the difference between field strengthmedium value of outside and inside the buildings. The higher the band, thestronger the penetration capability, but the smaller the diffraction. Indoor radiowave can be considered as the summation of penetration component anddiffraction component. The penetration of 2G frequency band is stronger than

that of 900M, while its diffraction is less than that of 900M. For 2G frequency,the distribution of indoor signal is not uniform, with large electrical leveldistinction for the same location. Generally, more penetration is reserved for 2G frequency bands, which is about 5dB more than that of the 900Mpenetration value in the similar area. It is also related to the building materialand its thickness.

Area type 900M loss dB 2G loss dB DU 18 22 23 27 MU 15 20 20 25

SU 10 15 15 20 RU 8~10 10~15 Express way 5~8 8~10



Gain of antenna

BS antenna gain

BS antenna gain is related to the type of the antenna. Usually, gain of directionalantenna is15~20dBi, gain of Omni antennais about 11dBi, and gain of directionalantenna is about 17dBi. For the coverageantenna of indoor distribution system, thegain of wide-frequency directional antennais 7-10dBi, while that for wide-frequencyOmni antenna is 2-5dBi.UE antenna gainUE antenna gain is related to the type of the UE. Usually, gain of the voice terminalantenna is considered as 0dBi, while thatfor data card is 2dBi.Gain diversityCoherent combination for signal, and non-coherent combination for noise.Generally considered as 2.5 3dB.



Shadow fading margin

Shadow fading margin fading margin In order that BS can cover the edge of the cell with a certainprobability, BS must reserve a certain transmission power toovercome the shadow fading, and these reserved power is actuallyfading margin.Due to shadow fading, the path loss in a fixed distance can bealternative in a certain range. In order to ensure the signal strength, acertain amount must be reserved to overcome this change.Generally, shadow fading is believed to comply with log-normaldistribution. The required shadow fading margin can be obtainedaccording to the shadowing fading variance and edge coverageprobability (or area coverage probability).

received signal level [dBm]

probability density

F median (x)threshold

x



Gain of Soft Handover

Gain of Soft Handover Due to the combination of macro diversity, when amobile equipment is in the soft handover area,multiple links of soft handover will receive it at thesame time, which reduced the requirement of shadow fading margin. Generally, gain of multi-cellsoft handover in the link budget is 1~3dB.

Soft handover area



Power Control Margin

Power Control Margin (Fast fading margin)Used for the resistance to power control fluctuation range of fast fading(Rayleigh fading). Low-speed mobile equipment mainly uses fast closed-looppower control to ensure its demodulation. In order that fast power control isstill effective when UE is at the edge of the cell, a dynamic adjustable scope,which is usually 3dB, must be reserved for fast power control. As to mediumand high speed UE, interleaving in channel encoding is mainly used to counter

fast fading, while fast power control is of very little effect, and power controlmargin becomes unnecessary to reserve.



Penetration loss

The penetration loss of buildings and vehicles is an importantfactor that influences the radio coverage. The penetration lossis related to the specific building/vehicle type and incidentangle of radio wave. Suppose that the penetration losscomplies with lognormal distribution during link budget, anduse the average value of penetration loss and standarddeviation to describe it. If the radio coverage outside buildingsis effective, it is enough to set the penetration loss to 10dB –15dB. To receive and initiate calls at the core part of a building,it is necessary to set the penetration loss to 30dB. Similarly,the penetration loss is also important to the coverage insidevehicles. A car has the penetration loss of 3dB to 6dB, andvans and buses may have larger changes. The penetrationloss at the front of vans should not exceed that of cars, but that

at the rear of vans may reach 10dB to 12dB. The specific valueis dependent on the number of windows. Therefore, it isnecessary to set a reasonable penetration loss value inaccordance with actual conditions of the planning region duringlink budget to guarantee good service quality.



Basic Types for Link Budget

Uplink/downlink budget for R99 service channelLink budget for public pilot frequency channelHSDPA link budgetHSUPA link budget



Parameters Symbol computationMax transmission power of UE AAntenna gain of UE BUE Transmission loss (human loss) CActual max transmission power at eachchannel of UE

D= A +B – C

Spectral density of thermal noise inenvironment

E

BS noise coefficient FSpectral density of the noise powerreceived by UE

G = E +F

Uplink interference margin HSpectral density of the total noisepower received at UE uplink

I = G + H

Uplink signal quality requirementEb/No

J

Uplink service speed KUplink receiving sensibility L = I + 10lg(3.84*10 6) +(J – 10lg (3.84*10B 6/ k ))BS antenna gain MBS comprehensive loss N

Shadow fading margin PGain of soft handover QPower control margin RPenetration loss SMaximum loss T = D -L +M-N-P+Q-R-S

Basic Process for Uplink Budget

Max path loss Valid transmission power receiver sensitivity BS antenna gain cableloss feeder power control margin gain of soft handover shadow fading marginpenetration loss



Parameters Symbol computationMax transmission power at service

channelA

BS antenna transmission gain BFeeder loss CValid transmission power at service

channelD= A +B – C

Spectral density of thermal noisepower in environment

E

UE noise coefficient FSpectral density of noise power

received by UEG = E +F

Downlink interference margin HSpectral density of the total

interference power received by UEI = G + H

Downlink signal quality requirementEb/No

J

Downlink service speed KDownlink receiving sensitivity L = I + 10lg(3.84*10 6) +(J – 10lg (3.84*10 6/ k ))

UE receiving antenna gain MHuman loss N

Shadow fading margin PGain of soft handover QPower control margin R

Penetration loss SMaximum loss T = D -L +M-N-P+Q-R-S

Basic Process for Downlink Budget

Max path loss Valid transmission power receiver sensitivity BS antenna gain cable loss feeder power control margin gain of soft handover shadow fading margin penetration loss



Differences between Uplink and DownlinkBudget Process

Different transmission power occupationUplink transmission power of UE is dedicatedDownlink transmission power of BS is shared by all thechannels, the available UE powers are related to UEnumber, UE distribution, UE speed and so on.For actual system, in order to avoid the over occupationof BS power resource by single UE, maximumtransmission power for each service is limited.

CS12.2K CS64K PS64K PS128K PS384K

Maxtransmissionpower atservicechannel (dbm)

33 36 38 38 38



Different service has different coverage

Link Budget for R99 Service Channel



Parameters Symbol computation

Transmission power of public pilot frequencychannel

A

Transmission gain of BS antenna B

Feeder loss C

Valid transmission power of public pilot

frequency channel

D= A +B – C

Pilot frequency strength required bydownlink receiving Ec

E

Gain of UE receiving antenna F

Shadow fading margin G

Penetration loss HMaximum loss I = D -E +F-G-H

Basic Process for the Link Budget of PublicPilot Frequency Channels

The biggest difference from service channel link budget is that, there are no softhandover gain and power control margin for the link budget of public pilotfrequency channel



Link budget differences between public pilotfrequency channel and R99 service channel

The received signal

strength of public pilot

frequency channel is

usually preset, but not

calculated through S/N

No body loss

No power control

margin

No handover gain



HSDPA Link Budget ProcessParameters Symbol Calculation process

HSDPA transmission power (dBm) A

BS antenna gain (dBi) B

BS feeder loss (dB) C

Valid radiation power of HSDPA (dBm) D D=A+B-C

Thermal noise (dBm) E

Receiver noise coefficient (dB)F

Receiver noise (dBm) G G=E+F

Service speed (kbps) H

Processing gain (dB) I

Es/ N 0 (dB) J

Receiver sensitivity (dBm) K K=G+J-I

Interference margin (dB) L

UE antenna gain (dBi) M

Shadow fading margin (dB) N

Penetration loss (dB) O

The max allowed path loss P P=D-K-L+M-N-O



Link Budget Process between HSDPA andR99

Due to the alternative speed

of HSDPA, there is no fixedvalue for Eb/N0. During linkbudget, symbolic S/N Es/ N0,instead of Eb/ N0, is used asthe calculating parameter for receiver sensitivity. The valueof Es/ N0 is related to HSDPA

data speed, which can beobtained from the table.Processing gain is fixedat12dB( spreading factor of HS-PDSCH code channel isfixed at16)No body lossNo power control marginNo handover gain



HSDPA Link Budget ProcessParameters Symbol Computation process

HSUPA transmission power (dBm) AHS-DPCCH power overhead (dB) B

UE antenna gain (dBi) C

UE feeder loss (dB) D

Valid radiation power of HSUPA (dBm) E E=A-B+C-D

Thermal noise (dBm) F

Receiver noise coefficient (dB) G

Receiver noise (dBm) H H=F+G

Service speed (kbps) I

Ec/ N 0 (dB) J

Receiver sensitivity (dBm) K K=H+J

Interference margin (dB) L

BS antenna gain (dBi) M

Shadow fading margin (dB) N

Penetration loss (dB) O

The max allowed path loss P P=E-K-L+M-N-O



Link Budget Process between HSUPA and

Due to the alternative speed of

HSUPA, there is no fixed value of Eb/N0. During link budget, empty

Ec/N0 value is used as the calculating

parameter for receiving sensitivity, and

the value of Ec/N0 is related to the

speed of HSUPA and type of terminal,

which can be obtained from the table.

While calculating the valid radiation

power of HSUPA, the UE power back-

off effects caused by the uplink HS-

DPCCH channel of HSDPA need to be

considered. As HSUPA is introducedafter the network building of HSDPA;

therefore, a HSUPA user is usually also

a HSDPA user, and effects caused by

HS-DPCCH channel need to be

considered.



Input: System load requirement,coverage requirement

Link budget for uplink service

Link budget for downlink service

Link budget for public pilot

frequencychannel

Take theminimum value

Complete

Take theminimum link budget value

required bycontinuouscoverage

Calculate coverage radius, area andsize according to transmitting model

and station type

Coverage Estimation Process



Frequently used transmitting models

Transmitting modelThe max allowedtransmission loss

Cell radiusinput output

Transmittingmodel

Form Adaptive scope

Cost231-Hata L=46.3+33.9lg(f)-13.82lg(h b)+(44.9-6.55lg(h b))lg(d)+Cm

1500~2000MHz macrocellular prediction

Okumura-Hata

L=46.3+33.9lg(f)-13.82lg(hb)+(44.9-

6.55lg(h b))lg(d)+Cm150~1500MHz macro cellular prediction

General L=k1+k2lg(d)+k3h m+k4lg(h m)+k5lg(h b)+k6lg(h b)lg(d)+k7(diffraction loss)+clutter loss

150~2000MHz macro cellular prediction

Obtaining of Cell Coverage Radius



Transmitting model of radio wave Although the form of macro cell models are different, they are

basically ―slope -intercept‖ model Common formulaPath loss = k1 + k2log(d)+ k3Hms + k4log(Hms) +k5log(Heff) +k6log(Heff)log(d) + k7DiffLoss + clutterloss

K1 fading constant

K2 fading constant of distanceK3 K4 correction coefficient antenna of mobile stationantenna heightK5 K6 correction coefficient of BS antenna heightK7 correction coefficient of diffractionDiffLoss diffraction lossClutter Loss loss correction value for ground objectsD Distance between BS and mobilestation(Km)Hms valid height of mobile station antenna(m)Heff valid height of BS antenna(m)

d refers to the distance from mobilestation to BS antenna, and the unit isKm;

Heff refers to the valid height of BStransmission antenna, and the unit ism;

Hms is the height of mobile stationantenna, and the unit is m;diffraction loss is the scattering loss;

clutter loss is the loss correction factor of ground object

l i b S i d C



Relation between Station Type and CoverageArea

Omnistation

Directional station

(65 degree, triple-sector)

Directional station


Station distance D=1.5R

Area S=2.6R 2 S=1.95R 2 S=2.6R 2

R D 3

R D D

R

R D

Omni station

Directional station

(65 degree, triple-sector)Directional station


R D 3

Dense urbanCommon

urbanSuburban Rural Express way

Typical coverage radiuskm 0.3 0.6 0.6 1.2 1.2 3 5 10 10~15



Link Budget Example12.2kbps voice service,120km/hvehicle user, soft handover, suburbanenvironment

Transmissionstain

Max transmission power 21dBm

Body loss 3dB

Valid transmission power

receiver

Thermal noise density -174dBm/Hz

Noise coefficient of BS receiver 5.0dB

Density of received noise

Receiver noise power

Interference margin 3dB

Total valid interference

Processing gain

Required E b/N0 5dB


BS antenna gain 18dBi

Feeder loss 2dB

Other s

Power controlmargin

0dB

Vehiclepenetration loss 8dB

Maximum pathloss

Shadow fadingmargin

8dB

Soft handover gain

3dB

The allowedtransmissionloss

Cell coverageradius

In order to simplify the calculation,according to Okumura model, assumethe correction factor for suburbanarea is 8db, and the transmissionmodel test result will be LOSS 129.4+35.2log(r)



Link Budget Example144kbps real-time service, 3km/h, outdoor coverage for indoor user, soft handover,

urban environment

Transmissionstation

Maximum transmissionpower

24dBm

Body loss

Valid transmission power

Receiver

Thermal noise density -174dBm/HzNoise coefficient of BSreceiver

5.0dB

Density of the received noise

Power of the received noise

Interference margin 3dB

Total valid interferenceProcessing gain

Required E b/N0 1.5dB


BS antenna gain 18dBi

Feeder loss 2dB

Other s

Power controlmargin

3dB

Buildingpenetration loss

15dB

Maximum pathloss

Shadow fadingmargin

8dB

Soft handover gain

3dB

The allowedtransmissionloss

Cell coverageradius

In order to simplify the calculation,according to Okumura model, assumethe correction factor for suburban areais 8db, and the transmission model testresult will be LOSS 129.4+35.2log(r)



Capacity Estimation Overview

Capacity estimation overviewCellular network planning need to determine the

system capacity requirement first, that is how manyUEs will be in the system and how much traffic will begenerated by these UEs. This is the basis for

engineering design for the whole cellular network.The purpose of system capacity analysis is to reflect

as much as possible the actual and future capacityrequirement, and thus estimate the channel number that system required.Networking planning is implemented on the basis of

initial and future traffic distribution that obtainedthrough various statistics and calculation.




ErlangOne Erl refers to the traffic load when a communication lineis 100 continuously occupied for one hour.

Busy hour and BHCAThe hour with the maximum traffic in 24 hours of a day isgenerally referred as the busy hour:

The calling attempts during this hour is correspondentlycalled the ―Busy hour calling times‖ or ―Busy hour callingattempts‖, and also BHCA for short.

Call loss rateCall loss happens when all the channels of a mobile

communication system are occupied and new calling isinitialized; at this moment, the call will be unable to connectand thus lost, or blocked. Call loss rate is the probabilitywhen these calls get blocked.During planning, the GOS for service channel is generally2%.




Erlang-B tableErlang-B model formula described the relationamong service channel number, GOS (call lossrate), and the capability of traffic providing.

According to Erlang formula, traffic can be

calculated for circumstances of different GOS andchannel, and then collected as a Erlang-B table.Busy hour traffic for each user is the busy-hour traffic for each user is the calling attempts for each user in one dayis the busy hour concentration coefficient (the ratioof busy-hour traffic and traffic for the whole day)Busy-hour traffic for each user is usually set as0.025 0.03erl/user

36001

0

0



Capacity Estimation

Hybrid service based capacity estimation will calculaterespectively the uplink capacity and downlink capacity, andthen determine the cell capacity size.

Total serviceamount

Various service amount in theplanning area

CS12.2k CS64k

PS64kPS128k

PS384k

Erlang

tableSingle-cellservice amount

Cellnumbers



Uplink Interference Estimation

thermal jiup N P P N

lnT

of ceStrengthInterferencellsg Neighborin

of ceStrengthInterferenC

herma N

UE P

UE ELL Interfere P

thermal

j

i



Downlink Interference Estimation

thermal i DL N P P N )1(

noiseThermal

strengthinterferecelladjacent

strengthSignalcellfactor OrthogonalCELL

thermal

i

N

P

P



Factors for Uplink/Downlink System Load

Uplink load factor

Downlink load factor

N

j j

j j DL i

RW

N Eb

1

0)1(

N

j

j j j

UL

v R No Eb

W i

1

)/(1

1)1(

Downlink load is not only relatedto user numbers, but also closelyrelated to the orthogonal factor of downlink channel

Uplink noise rise reflected the rise of BS receiving power on thermal noise power resulted from user access

Downlink noise rise reflected the rise of of interference over thermal noise power resulted form the non-orthogonal nature on multiple paths



Uplink capacity is limited by interference rise

25 30 35 40 45 50 55 60 65

2

3

4

5

6

7

8

9

10

11

user number

n o i s e r i s e ( d B )

Shanghai dialect Minnan

dialect

Putonghu

a

Cantonese

Downlink capacity is limited by transmission



Downlink capacity is limited by transmissionpower

46 48 50 52 54 56 58 60 62 64

32

34

36

38

40

42

44

46

user number

T x

P o w

e r ( d B m )

Public channel

2 UEs

1 UE

3 UEs

.

.

.

Downlinkpower

Relation between Uplink/Downlink Capacity



Relation between Uplink/Downlink Capacityand Coverage

145

150

155

160

165

170

100 200 300 400 500 600 700 800 900 1000 1100 1200 1300Load per sector [kbps]

M a x .

a l l o w e

d

p a t h l o s s

[ d B ]

Better coverage

Downlinkload

curve

Uplink

loadcurve



Frequently Used Hybrid Capacity Estimation

Capacity estimation is a very important part for WCDMA network planning, which is closely relatedto the brief assessment of network investment cost.WCDMA is a hybrid service system, with the largeamount data service application as its highlight.Frequently used capacity estimation method for hybrid service:

Equivalent Erlangs methodPost Erlang-B methodCampbell method



Erlang-B table2% 5%

1 0.020 0.053

2 0.223 0.381

3 0.602 0.8994 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 6.216

11 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



Equivalent Erlang

Basic Principle to make a service equivalent to another service,calculate the total traffic (erl) of the equivalentservices and calculate the channel number needed bythis traffic.

Example Service S1 12erl each connection occupies onechannel Service S2 6erl each connection occupies 3

channels.



Equivalent Erlang

Method 1 S2 with 1erl S1 with 3erl

After querying Table erl-B, we know that altogether 39 channels are needed under 2% blocking rate.(service S1)

Method 2 S1 3erl S2 with 1erl

After querying Table erl-B, we know that 10erl needs 17channels resources (S2), that is 51 channel resourcesof S1 service under 2% blocking rate.



+

Low-speed

serviceequals

High-speedserviceequals

2 Erl low-speed

service

1 Erl high-speed

service

Different capacity isneeded to meet the thesame GoS

Equivalent Erlang

Calculating result is

related to

equivalence method



Post Erlang-B

Basic Principle to calculate the channel number required byeach service capacity respectively and add channels in anequivalent manner to obtain the channel number required bythe hybrid service capacity.Example:Service A: each connection occupies one channel and the totalis 12 erl;service B: each connection occupies 3 channels and the totalis 6 erl.19 channels are needed for service A (under 2% blocking rate);

12 service B channels are needed for service B (equivalent to12*3=36 service A channels, under 2% blocking rate)The two services need 19+36=55 channels totally.



Post Erlang-B

Calculate the network capacity in a special case

Suppose services S1 and S2 are the same kind, and eachconnection takes one channel. Then under 2% call lossrate:

S1 12erl, 19 channels needed S2 6erl, 12 channels needed.Totally 31 channels are needed.

However, as services S1 and S2 are the same kind, thetotal traffic is 12+6=18 erl. After querying Table erl-B, weknow that 26 channels are needed to meet the trafficdemand under 2% blocking rate. This result is obviouslycorrect.

Conclusion The calculation result through the Post Erlang

method is too pessimistic (31>26). The reason is that the BSchannels are shared among services, however, the PostErlang method factitiously separates the channels used by theservices, and thus, the BS channel resource utilization ratio isreduced.



1 Erl service A

1 Erl Service B

+

1 Erl service A and 1 Erlservice B

Differentcapacity isneeded to

meet the thesame GoS

A and B are the same service

Calculation result

is too pessimistic

Post Erlang-B



Campbell method--1Principle to make all services equivalent to a virtual service based on certain

rules, calculate the total traffic (erl) of this virtual service, count the virtual

channel number needed by this traffic, and convert the number into the actualchannel number that meets the network capacity.

The equivalent formula is as follows

indicates capacity factor. indicates hybrid service variance.

indicates hybrid service mean.

indicates the equivalent intensity of service i.

indicates the channel number needed by service i. indicates traffic of the virtual service.

indicates the virtual channel number needed by the virtualtraffic. query erlang-B table .Finally calculate Ci

c

aC Capacity ii

c fficOfferedTra

iii

iii

aerl

aerl

c

2

cv

ia

iC

OfferedTrafficCapacity



The capacity factor is

The virtual traffic is

altogether 21 virtual channels are needed to meet the virtual traffic under 2% blocking rate (virtual channel ).

Campbell method--2Example

service A: each connection occupies one channeland the total is 12 erl;

service B: each connection occupies 3 channels andthe total is 6 erl.

The hybrid service mean isThe hybrid service variance is 2.2

30

66

c

3036112ii aerl

6636112 222ii aerl

63.132.2

30 TrafficOfferedc

α

under 2% blocking rate, the channel number needed byeach service is shown as follows:Service A Service B 471)2.221(1C 493)2.221(2C



Comparison of the three methods

Service S1 12erl, 1 channel is needed for each connection

Service S2 6erl 3 channels are needed for each connection

Estimation method Required channelnumber

Conclusion

Equivalent ErlangMethod 1 39 Smaller

Method 2 51 Larger

Post Erlang-B 55 Larger

Campbell 47 or 49 Reasonable

Equivalent Erlang Method Can be used when one service takes a very large percentage,for example, when business proportion is very high for circuit field.Post erlang-B As Post Erlang method factitiously separates the channels used by the services,and thus, the BS channel resource utilization ratio is reduced. Campbell Method currently, the Campbell method is a more reasonable estimation methodfor hybrid service capacity. Under the same requirement of the service level GOS, diversifiedchannel resources are needed by different services, or, under the same channel resources,different services obtain diversified service levels. From this point of view, the Campbellmethod is more reasonable.



Calculation Comparison for Hybrid Capacity--2

Estimation for Post Erl method is larger Advantage and disadvantages of the two methods are asfollowes

Advantages Disadvantages

Post Erl 1.Simple principle, convenientcalculation, easy to understandand accept, widely used 2.QOS of every service isconsidered 3.More reasonable processing for PS service

1.Gain of resource sharing not considered, andestimation result is too conservative 2.Only interference is assessed in downlinkcapacity estimation, and capacity limitation thatcaused by insufficient BS power is notconsidered.

Campbell 1.Convenient calculation2.Estimation result is morereasonable

1.PS is handled the same as CS, which isunreasonable 2.Estimation process cannot indicate the QOSdifference for various services 3.Theory not precise enough, and hard toexplain or understand

Example of Capacity Estimation for Hybrid



Example of Capacity Estimation for HybridService 1

Assume that the service requirement of the planningarea is as follows:

service amplitude Erl

Voice 1 250

64kbps data 2 63

144kbps data 4 41

384kbps data 8 12




Example of Capacity Estimation for HybridService 2

Assume there are n cells in the planning area, thecapacity calculation process for each cell will be asfollows:

nnc

c

nnnnn

nnnnn

210

028.3

636meantrafficoffered

028.3636

1926

mean

variance

1926821414263250variance

636821414263250mean

222




p p y yService 3

Assume that 32 voice channels can be provided by each cellWith voice service as benchmark, according to formula

, the number of virtual channel will be capacity=(32-1)/3.082=10.06integer is 10 Under 2% blocking rate, the erl that correspond to channel number 10will be 5.05

c

aC Capacity ii




p p y yService 4

From equation 210/n=5.05, we will know n=4232 cells and 14 triple-sector BSs are needed to meetthe capacity requirement.

S i M d l d T l T ffi f A



Voice

service

Video

call Email MMS

Information

service

Picture &ringtonedownload

WEP

browsing

www

browsing

Audio

steam

Video

stream

(erl) (erl) (bps) (bps) (bps) (bps) (bps) (bps) (bps) (bps)

Singleuser

service

dense 0.025 0.002 49.041 16.347 12.26 22.869 101.64 288.97 107.51 193.51

Normal 0.02 0.0015 24.521 8.1736 6.1302 11.435 50.82 144.49 61.433 82.935

Permeability

Dense 100% 20% 30% 50% 80% 60% 50% 30% 20% 20%

Normal 100% 20% 25% 40% 70% 50% 40% 20% 15% 15%

Downlinksingle-

usermultip

lypermeabi

lity

Dense 0.025 0.0004 14.712 8.1736 9.8083 13.721 50.82 86.691 21.502 38.703

Normal 0.02 0.0003 6.1302 3.2694 4.2911 5.7173 20.328 28.897 9.215 12.44

Dense 32.69427778 151.233044 60.20455923

Normal 13.69072882 54.94248092 21.65521136

Downlinktotal

throughput kbps

Dense 1144.299722 5293.15654 2107.159573

Normal 1505.98017 6043.672902 2382.073249

Downlinktotal

Erlang (er l)

Dense 875 14 17.87968316 41.35278547 5.487394721

Normal 2200 33 23.53094016 47.21619454 6.203315753

Uplinktotal

Erlang (er l)

Dense 875 14 15.197731 12.514439 0.446831

normal 2200 33 19.843256 14.782336 0.530581

Service Model and Total Traffic of an Area

HSPA applicability analysis of traditional



pp y yR99 capacity estimation

Traditional R99 capacity estimation is only applicable for the estimation of fixed speed distribution service in R99.

And the service must have a clear signal quality valueEb/No, service speed, etc..The technical characteristic of HSPA is self adapting and

adjusting the code modulation method and the occupiedcode channel resource. Service speed obtained by user is alternative, and it is tolerant for the rise of resendingrate to achieve the reduction of Eb/No. Therefore, thetraditional R99 capacity estimation method is not

applicable for HSPA.HSPA has no clear service speed and Eb/No, thus

the traditional R99 capacity estimation method is

not applicable for HSPA

Capacity Estimation Method for HSDPA and



p yHSUPA

Basic Principle: Obtain the HSDPA and HSUPA throughput that

supported by the cell on the basis of simulation and actual survey.Main Tool: 3GSS platform

The Hybrid Capacity Estimation Method



y p yWhen Frequency is Shared by R99 and HSPA

First, make sure it is same frequency or not for R99 and HSPA. If it is different

frequency, capacity estimation need to be performed respectively for R99,HSDPA, HSUPA, and the maximum value of the three will be taken as the finalresult of capacity estimation. The following conditions are mainly concerned for the network building of hybrid frequency between R99 and HSPA Reserve initial resource for HSPA. At present, 5% uplink load is initiallyreserved for HSUPA, while power of 4W is initially reserved for HSDPAdownlink. (amplifier of 20W) Take R99 network planning at first, and determine the single-station user scale,cell radius, BS number based on R99 On the basis of the estimated R99 BS scale, calculate single-cell throughput of HSUPA and HSDPA, and check if the reserved uplink/downlink resource canmeet the HSUPA & HSDPA single-cell throughput requirement.If HSPA flow is fulfilled, the capacity estimation result will be output; If not,

jump to the first step, increase the reserved resource, and perform iteration.Currently, the adjustable step for HSUPA uplink download is 5%, and that for HSDPA power resource is1w.

The Hybrid Capacity Estimation Method



y p yWhen Frequency is Shared by R99 and HSPA

The key point for hybrid

capacity estimation of R99

and HSPA is how toreasonably allocate limited

resources between R99 and

HSPA

Content



Content

Introduction to WCDMA Scale Estimation

Method for WCDMA Scale Estimation

Case Study of WCDMA Scale Estimation

Requirement 1



Requirement 1

Basic design requirement

Planning area Dense urban 20km2User number: 30 000Blocking rate for voice service and video call service 2%Soft handover rate 30

Frequency band: 1920~2170MHzCoverage requirement

Continuous coverage is required for video call serviceSpeed at cell edge of HSDPA should be no less than300kbpsSpeed at cell edge of HSUPA should be no less than200kbps

Area coverage rate should be no less than 95%Indoor continuous coverage

Requirement 2



Requirement 2

Capacity requirement

Basic Assumption



Basic Assumption

Station type selection20W macro cellular, S111 station type

Antenna selectionDirectional antenna, with gain of 18dBi and height of 30mTransmitting modelCost231-Hata dense urban modelBuilding of shared frequency by HSPA and R99

Designed uplink load:75%

Analysis Process —Link Budget



Analysis Process Link Budget

Analysis Process —Coverage Estimation



ResultContinuous coverage radius for CS64K: 0.32kmCoverage radius for HSDPA 300kbps is 0.39kmCoverage radius for HSUPA 200kbps is 0.49kmThe final cell coverage radius: 0.32km

Total coverage scale: 99 S111 Node B

Analysis Process —Capacity estimation 1



Traffic statistics Uplink capacity estimation

Campbellmethod

Systemsimulation

Analysis Process Capacity estimation 1

Analysis Process —Capacity estimation 2



Downlinkcapacityestimation

Campbellmethod

Systemsimulation

Take intoconsideration theresult of uplink/downlink

capacityestimation, finally47 S111 Node Bare required tomeet the capacity

requirement for the planning area

Analysis Process Capacity estimation 2

Analysis Process —Final scale



Analysis Process Final scale

Finally 99 S111 Node B are required to meet thecapacity requirement for the planning areaFinally 47 S111 Node B are required to meet thecapacity requirement for the planning areaTotal scale: 99 S111 Node BNetwork coverage limited

WPO-07 WCDMA Scale Estimation-90

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