RF Link Budget and Dimensioning

1 © Nokia Siemens Networks WCDMA Network Link Budget and Dimensioning/Deepak Yadav/Aug2008Company Confidential

WCDMA Link Budget & Network Dimensioning

2 © Nokia Siemens Networks WCDMA Network Link Budget and DimensioningCompany Confidential

Radio NW Planning

-> What is a good RF Network Plan?

– A good network plan should address the coverage and capacity requirement of the area considered, but also be sufficiently flexible to allow network expansion without major change of the existing sites.

WCDMA RF Plan

– In WCDMA, the coverage and capacity requirement cannot be considered independently, but should be planned at the same time with proper guidelines


Radio Network Planning Process

• Radio Planning Objectives : Coverage, Capacity, Quality and Cost

•Planning Process

Optimisation

Pre-launchoptimisation

Pre-planning Detailed planning

Pre-planninginformation

Dimensioning

Model tuning

Site selection

Configurationplanning

Parameterplanning

Coverage and capacity planning

Pre-launchoptimisation

Post-launch optimsation

Scope of

Dimensioning


Scope of Dimensioning

CN

Circuitswitched

(cs) domain

packetswitched

(ps)domain

UTRAN

Iub

Iub

Iur

Iu-PS

Iu-CS

Uu

Uu

UE

UE

MSC/VLR

SGSN

RNC

RNC


-Ou

tpu

t tow

ard

Ac

ce

ss

p

lan

nin

g

Per area and per Phase

• Number of Node Bs

• Node B Type

• Node B Configuration

• Node B Upgrade

Radio Dimensioning flow

customerRequirements

LINK BUDGETLINK BUDGET

RF Planning Parameters• interf marg

• HO gain• environment

• etc.

RF Planning Parameters• interf marg

• HO gain• environment

• etc.

System Parameters

• Eb/No• TX power

• etc.

System Parameters

• Eb/No• TX power

• etc.

Infrastr. Parameters• # of sectors• antennas• req cov

area• etc.

Infrastr. Parameters• # of sectors• antennas• req cov

area• etc.

CapacityCapacity

Air Interface Dimensioning

(Capacity: Rel’99 + HSPA)

Traffic Demand

• per bearer• # of subs

• GoS• etc.

Traffic Demand

• per bearer• # of subs

• GoS• etc.

Outputs

Input Parameters

Target ServiceTarget Service


Link Budget Overview

Noise figure

Cable losses

Soft handover gain,

antenna gain

Building Penetration loss

Body loss

Margins

PATH LOSS (L)

Max AllowedPath Loss (L)

= Tx Signal + All Gains – Other Losses – Rx Sensitivity


Link Budget Overview

Margins

PATH LOSS (L)

MS out power EbNo RequiredBody lossMS antenna gainBuilding Penetration loss

Location probabilityPropagation environmentCoverage criteriaSHO gain

BS noise figureRequired Eb/NoProcessing gainUplink loadBTS cable and connector lossesBTS antenna gain


Input Parameters Overview

CAPACITY RELATED Spectrum Available Subscriber Growth

Forecast Traffic Density Map

CAPACITY RELATED Spectrum Available Subscriber Growth

Forecast Traffic Density Map

COVERAGE RELATED Coverage Regions Area Type Information Propagation Model

COVERAGE RELATED Coverage Regions Area Type Information Propagation Model

QUALITY RELATED Indoor/Outdoor Coverage Location Probability Blocking Probability

QUALITY RELATED Indoor/Outdoor Coverage Location Probability Blocking Probability

Gives an Estimation of the Equipment Necessary to Meet the Network Requirements

Network Dimensioning Activities

Radio Link Budget Calculation

Cell Size Calculation Capacity Calculation Number of Node B, RNC Iub, Iur & Iu

Transmission Capacity

Gives an Estimation of the Equipment Necessary to Meet the Network Requirements

Network Dimensioning Activities

Radio Link Budget Calculation

Cell Size Calculation Capacity Calculation Number of Node B, RNC Iub, Iur & Iu

Transmission Capacity

Input Categories


Radio networks Dimensioning

COVERAGECOVERAGE CAPACITYCAPACITY

COMPROMISE BETWEEN COVERAGE AND CAPACITYCOMPROMISE BETWEEN COVERAGE AND CAPACITY


WCDMA Capacity


It must be ensured that network is planned with limiting link to ensure the coverage for all the bearers R99 uniformly in all clutters.

In Design HSPA is the Limiting Link , Since cell range for this link is minimum, so network should be planned using this cell range

DLUL

DLUL

DLUL

Voice

HSPA

CS 64

Network Design Criteria: Limiting Link


Network Planned with 20% loading

Coverage holes in the network When 30% loading

Limiting Link

Network Dimensioning



Coverage VS Capacity Dimensioning: Cell Breathing [1/2]

Traffic distribution and forecase uncertainty and imperfect site selection

Cell-A

Cell-C

Cell-B

Results => Results => Coverage Holes!Coverage Holes!

Cell-A

Cell-C

Cell-B

Cell breathing

"actual" Loading, (ie from the traffic inputs defined in dimensioning)

e.g.. Forecasted Actual UL load = 8%

e.g.. Real Actual UL load = 30%


Coverage VS Capacity Dimensioning:Fixed Uplink Load - To avoid Coverage holes [2/2]

"actual" Loading, (ie from the traffic inputs defined in dimensioning)

This diagram shows a Fixed Uplink Load design

Results => No or Results => No or Min Coverage Min Coverage Holes!Holes!

Cell-A

Cell-C

Cell-B

Cell-A

Cell-D

Cell-H

Cell-E

Cell-F

Cell-C

Cell-B

Cell-G

• No (or minimum)

coverage holes

problems

• More cells required

• Traffic mobility taken

into account.

eg. Actual UL load = 8%

eg. Fixed UL load = 30%


Inputs for Coverage Planning


Requirements in Coverage Planning

Link Budget Parameters

Clutter Type

Size of Area

Bearers

cell load

Results from Coverage Planning

Cell Radius

Total number of NodeB


Coverage Planning


Key Inputs for Coverage Planning

DU U SU R

Target Service at Cell EdgeTx PowerUL Cell LoadingFast Fading Margin dBSHO gain dB

Penetration Loss 24 20 16 10 dB

Feeder Loss 1 1 1 1 dB50% NodeB with 2.5dB feeder loss

Node B Antenna height 20 20 22 24 m

UE antenna height 1.5 1.5 1.5 1.5 m

Nde B antenna gain 18.5 18.5 18.5 18.5 dBi65 degree horizontal beamwidth

Area coverage probability for voice and video 95% 95% 95% 95%Standard deviation 10 8 8 6 dBArea correction factor 0 0 -4 -4 dB

CS 64kbpsUE: 21dBm; Node B 20W

35%33

ClutterParameters

UnitRemarks


Coverage Planning Inputs : Clutter Area Distribution


Inputs for Capacity Planning



Requirements in Capacity Planning

• No. of Subscribers

• Services and Bearers

• Traffic Profile per subscriber

Results from Capacity Planning

• Cell Load

• Channel Element

Capacity Planning


Capacity Inputs – Number of Subscribers


Capacity Inputs – Traffic Profile


Sample Format for Traffic Profile


Capacity Inputs – Subscriber Distribution

Subscriber Distribution Clutter Level

PhaseDense Urban Urban

Sub Urban Rural

Year 1 15% 45% 30% 10%

Year 2 17% 48% 28% 7%

Year 3 18% 48% 27% 7%


WCDMA Link Budget


IntroductionLink Budget Main Sections

• General Settings

– Supported Release (not shown, new for version v1.1.1), Clutter Type, Channel Model, Bearer type, Operating Band, RF part selection

• Transmitting End Settings (NodeB and UE as well)

– Feeder, Antenna, CCCH settings

• Receiving End Settings (NodeB and UE)

– TMA, Load settings

• Pathloss Setting

– Propagation Model selection, Standard Deviations, Penetration Loss, Location Probability, Antenna height

• Radio Network Configurations Settings

– Site Layout, Area Size, Required Coverage settings


UE Tx power = 21dBm

Node B Tx Power = 43 dBm

Antenna Gain (example): 18.5 dBi, X-pol, 650

Feeder Loss

Body proximity Loss

3 dB for voice services

1dB for Video Service

0 dB for data services

Link Budget : Tx End Parameters


Total noise power in the receiver is a

function of:

• Boltzman’s constant

• Temperature

• Bandwidth

• Thermal Noise = kTB

• Noise figure

Link Budget: Rx End Parameters


Path Loss = Processing Gain - Thermal Noise

= log (3840000/Information Rate) – log (kTB)

= log (3840000) – log (information rate)

– log (kT)

– log (3840000)

Link Budget : Information Rate and Processing Gain


• Interference margin is calculated from the UL

loading () value

– From set maximum planned load

• "sensitivity" is decreased due to the network load (subscribers in the network) & in UL indicates the loss in link budget due to load.

20

10

6

1.253

25% 50% 75% 99%

IMargin [dB]

Load factor

20

10

6

1.253

25% 50% 75% 99%

IMargin [dB]

Load factor

dBLogIMargin 110 10

Link Budget: Load and Interference Margin


In order to meet the defined quality requirements (BLER) a certain average bit-energy divided by total noise+interference spectral density (Eb/N0) is needed.

Eb/No depends on:

• Service

• MS speed

• Radio channel

ServiceUL DL

CS 12.2 AMR voice 4.4 7.3CS 64 (video call) 2.2 4.9PS 64 2 3.8PS 128kbps 1.4 3PS 384kbps 1.7 3.6

Eb/No

Link Budget : Eb/No


Soft HO

Softer HO

• SHO gain, also called Macro Diversity Combining, gives the Eb/N0 improvement in soft handover situation compared to a single link connection

• In dimensioning SHO Gain is considered at the cell edge

• This phenomenon reduces the negative effect of small scale fading

• It allows to use lower the transmit power or EbNo requirements

• In Link Budget tool this parameters is covering gain of soft and softer handover

Link Budget: SHO Gain


At cell edge there is the gain against shadowing. This is roughly the gain of a handover algorithm, in which the best BTS can always be chosen (based on minimal transmission power of MS)

In reality the gain against shadowing gain is a function of required coverage probability and the standard deviation of the signal for the environment.

• This gain can be understood as reduction of Shadowing Margin

Link Budget: Gain against shadowing


• Describes a margin taken into account as a power backup at the transmitting end

• This margin reflects the accuracy of the closed loop fast power control algorithm to follow the steep fluctuations of the link loss caused by the fast fading

• This is needed at cell edge for UEs to be able to compensate fast fading

0 0.5 1 1.5 2 2.5 3 3.5 410

15

20

25

dB

0 0.5 1 1.5 2 2.5 3 3.5 4-10

0

10

20

dBm

0 0.5 1 1.5 2 2.5 3 3.5 4-0.5

0

0.5

1

1.5

0 0.5 1 1.5 2 2.5 3 3.5 45

10

15

dB

Seconds

Mobile transmission power starts hitting its maximum value

Eb/N0 targetincreases fast

Received qualitydegrades, more

frame errors

MS moving towards the cell edge

Link Budget: Fast Fading Margin


Link Budget: Radio Propagation specific Inputs

Antenna Height

Standard Deviation

Coverage Probability

Penetration Loss

Propagation Model


Link Budget Results

Allowed Pathloss

Cell Radius


In the dimensioning process, the cell range [R]

is set by the shortest radio link (service class

With lowest cell range).

The number of sites can be determined by the

following relation:

# of sites = coverage area / site area

where: site area = K * R2

Sector K value

Omni 2.6

1 0.65

2 1.30

3 1.95

6 2.60

Coverage Site Count Calculation


WCDMA Radio NW Planning – Dimensioning Process Summary

Link Budget CalculationRadio link specific :- Data rate (processing gain)- Average Eb/No- SHO gain in dB

Equipment specific :- MS Power class- MS/BS calc. sensitivity- Antenna gainetc

Load factorPropagation specific :- Antenna height- BPL and deviation- Area correction factor- Lognormal shadowing margin

Max. allowed path loss

Cell Range Calculation

Max. Cell Range in each area type

Capacity Estimate

No. of sites / Total supported traffic in each area type

Equipment Requirement

BS HWs / Transmission / RNC

Estimated traffic per CU

InterferenceMargin

Max. traffic per CU

If fulfill the need

If too low capacity


Load Calculation


Load Calculation

Load factor () predicts the amount of noise rise by treating interference as wideband noise.

It is based on Eb/No, number of users, their service bit rate and activity, other cell to own cell interference ratio, the amount of uplink noise rise and orthogonality factor.


Load Calculation

In order to meet the defined quality requirements (BLER) a certain average bit-energy divided by total noise+interference spectral density (Eb/N0) is needed. So for every user j and for given bit rate Rj we have:

, where Ij is the received signal power of user j

Of course subscriber j is not active all the time, that is why the special activity factor j should be introduced:

jjtot

j

jj

b

II

I

R

W

N

E

1

0

jtot

j

jj

b

II

I

R

W

N

E

0


Load Calculation

Using the previous equation we can express the load caused by one subscriber as a part of the total load:

, where:

For N subscribers, the load caused in the cell (so called load factor) is:

jjb

jj

NE

RWload

1

1

1

0

totjj IloadI

N

jjload


Little i

The load factor calculation the other cell interference takes into account the interference from other cells.

This can be introduced by means of the little i value, which describes how much two cells overlap (bigger overlapping more inter-cell interferences).

Iown

Iother

Sector Little i

Omni 0.55

3 0.65* recommended values


Interference in UL

PRx_Own

PRx_Other

iUL = PRx_Other / PRx_Own


Interference in DL

PTx_Own

PTx_Common

Com

mon

Cha

nnel

s

PTx_Own_DL

PTx_Other_DL

iDL = PTx_Other_DL / PTx_Own_DL


Orthogonality

Orthogonality [] is a measure how well separate code signals are uncorrelated

In DL the own cell interference are reduced by factor (1-). This is due to the synchronised orthogonal channelisation codes, which are used in DL.

recommended value: [] = 50%


Load Calculation

After introduction of the little i the load factor in the cell will be:

In DL the own cell interference is reduced by factor (1-). This is due to the synchronised orthogonal channelisation codes, which are used in DL:

N

jjloadi1

N

jjjDL loadi 1

• Ortogonality factor j is between 0.4 and 0.9Typical values:

• ITU vehicular subscriber (Macro Cell) j=0.6

• ITU pedestrian subscriber (Micro Cell) j=0.9


Power Rise

For UEs located in the other cells the power increase caused by Fast Loop PC procedure is harmful for the own cell interference conditions

N o n - f a d i n g c h a n n e l F a d i n g c h a n n e l

T r a n s m i t t e d p o w e r

R e c e i v e d p o w e r

P o w e r r i s e

A v e r a g e t r a n s m i t t e d p o w e r

N o n - f a d i n g c h a n n e l F a d i n g c h a n n e l

T r a n s m i t t e d p o w e r

R e c e i v e d p o w e r

P o w e r r i s e

A v e r a g e t r a n s m i t t e d p o w e r

recommended value: [pwr_rise] = 0.7 dB


Load Calculation

Because of power rise in the UL load calculation, the little i should be corrected (little i is multiplied by pw_rise parameter)

UL load affects the noise level at the Node B receiver. Noise RiseA typical cell load value for dimensioning ranges from 30% to 70 %.

50% is a good compromise between the number of sites and the offered capacity.Breathing effect: UL load limits the Coverage.

0

2

4

6

8

10

12

14

16

18

10

20

30

40

50

60

70

80

90

95

98

loading/%

los

s/d

B

N

jjUL loadirisepw_1


Dimensioning Results

RF DIMENSIONING RESULTS

Number of base stations

Configuration of base stations

Number of subscribers per area

mErl / subs for voice and RT data

mErl / sub for NRT data

Iub/Iur/Iu INTERFACE DIMENSIONING

RNC DIMENSIONING


Cell Load Calculation


WCDMA Network Dimensioning Results Analysis


Understanding Target Service – CS64 (DL)

CS64

PS64

CS64

PS384 CS64

PS128

AMR12.2CS64

AMR12.2

AMR12.2

AMR12.2

AMR12.2AMR12.2

PS384

PS128

PS64

PS64

Cell Edge


Understanding Target Service – CS64 (UL)

CS64

PS64

CS64

CS64

AMR12.2CS64

AMR12.2

AMR12.2

AMR12.2

AMR12.2AMR12.2

PS384

PS128

PS64

PS64

Cell Edge


Understanding Target Service – HSDPA

Cell Edge

High Throughput

Low Throughput


Target Service

CS64

PS64

New Zealand

Taiwan

Malaysia

Philippines 1

Philippines 2

Singapore

Indonesia

PS64

PS64

PS64

PS128

HSDPA512/PS128


Service v/s Cell Radius [ Asymmetrical Traffic]

With UL fixed at 64Kbps, Limiting Link is CS64


Service v/s Cell Radius [ Symmetrical Traffic]

In Symmetrical traffic environment, PS384Kbps is the limiting link


Sample Site Count Comparison – Change of Target Service


Sample Site Count Comparison – Change of Interference Margins

≈ ∆1.75dB

dBLogIMargin 110 10

1.253

20

10

6

25% 50% 75% 99%

IMargin [dB]

Load factor


Sample Site Count Comparison – Change of Interference Margins

≈ ∆1.5dB

≈ ∆15%

≈ ∆1.5dB

≈ ∆15%


Deviation In Results – Change of Planning Inputs


GSM900 v/s GSM1800 v/s WCDMA


GSM900 v/s GSM1800 v/s WCDMA


WCDMA Network PlanningSample Case


Top 19 cities planning – An Overview


Remove Existing Sites which are too close to each

other

Coverage Prediction

Target Design

Import exiting sites in planning tool And evaluate based on design criteria

Generate Coverage Stats

Too Much Coverage Overlap?

Yes

No

Coverage Stats fulfilling the criteria?

No

Nominal Planning Process

Any Coverage

Holes?

Add new 3G sites to fill up coverage holes in network

Yes

No

Yes


Summary of Link Budget I – CS64


Summary of Link Budget II – Cell Range


Radio Planning Results - Summary of Site Count


Understanding Results – Comparison of Reuse Factors


Understanding Results – Comparison of Reuse Factors

Avg Reuse approx 85%


Delhi Radio NW Planning Results Analysis


Coverage Planning Delhi – Clutter Map

Dense Urban Urban Sub Urban Rural Total

53.0 175.3 418.6 17.1 663.9


Delhi Coverage Planning Outcome

65-70% sites in DU and U area

Site

Percentage

Dense Urban 54 8.21% 243 19.57%

Urban 335.94 42.03% 547 44.04%

Suburban 370.95 46.41% 345 27.78%

Rural 26.734 3.34% 107 8.62%

TOTAL 787.624 1242

Morphology Area* (km2) Percentage Sites No.

*Site count shown above is inidicative and purely based on certain assumptions. Also significant clutter area details used in above figures is based on map area details provided by map vendor to NSN


Coverage Planning : RSCP Plots


Delhi Coverage Planning : Ec/Io Plots


Delhi Coverage Planning: SHO Area Analysis


WCDMA Network DimensioningCE Dimensioning Aspects


Baseband (BB) capacity• Channel Element (CE) refers to the capacity requirement of 1

User voice/16 kbps (UL&DL)

• Upgrades in min. 1CE (Channel Element) steps

• Additional CE by SW license key

• HW supports CCH, DCH, HSDPA and HSUPA

• 384 kbps supported in UL and DL for both HSDPA and R99 services

Flexi WCDMA BTS Site Capacity


Flexi BTS Base Band CE Requirements For R99 Users

User data CE required

16kbps/ voice 1

32kbps 2

64kbps 4

128kps (64/128) 4

128kps (128/128) 4

256kps (DL) (64/256) 9

384kbps (64/384) 12

384kbps (128/384) 12

384kbps (384/384) 12


Flexi WCDMA BTS BB Example

Common channels

Remaining availablecapacity for R99 traffic

Carrier 1Carrier 1Common channels

Carrier 1Carrier 1

Carrier 1Carrier 1Traffic channels

HSDPA Users

Based on traffic

requirements

activated CEHSUPA Users


Channels Element Calculation

The code channels (HW channels) needed for different services are as follows:

1. Traffic per CellErlang or kbit/s

3. Physical Channels(=traffic channels*SHO)

2. Traffic Channels

Hardware Channels

Service Code Channel

Voice 1

64 kbps service (RT/NRT)

4


4


12


Network Dimensioning Summary• Complete Network dimensioning in the end should provide following results -

– Cell Range– Site Area– Coverage Thresholds– Number of Coverage Sites– Achieved Loading– Number of carriers per cell– Number of capacity sites– CE requirement per site– Total Number of sites

• Dimensioning Outputs from Link Budget [ Libu Tool] :– Cell Range– Site Area– Coverage Thresholds– Number of Coverage Sites

• Dimensioning Outputs from Dim Tool :– Achieved Loading– Number of capacity sites [ If possible]– Total Number of Sites– CE requirement per site


Thanks!

Date post:	18-Jan-2016
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RF Link Budget and Dimensioning

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