Alcatel-Lucent UMTS Link Budget Methodology v1.0

UMTS Link Budget Methodology

Sylvestre Demonget

Wireless BG / W-CDMA BD /

Post-Sales Support & Technology Introduction / W-CDMA Network Engineering

April 2nd, 2007

2 | HSUPA Link Budget | February 28th, 2007 All Rights Reserved © Alcatel-Lucent 2006

Agenda

1. Uplink Link Budget Methodology

2. Downlink Link Budget Methodology

3. Capacity and Throughput Calculation Basics


Introduction

UMTS Link Budget methodology:

� Uplink: Cell Range derivation based on a specific UL dimensioning service

� Downlink:

� Calculation for each DL service of transmit power necessary to reach cell edge

� Comparison with maximum allowed power for this DL service

Aspects covered in this presentation:

� Link budget methodology (UL and DL) applicable to both Release 99 and HSPA

� Cell Range comparisons for multiple:

� R’99 UL services

� HSUPA user throughput targets

� UL and DL Capacity calculation using analytic formulas

� HSPA Throughput computation using static simulation:

� Throughput map

� Throughput Vs. Distance from Site


Agenda





1UMTS Uplink Link Budget

Methodology, Cell Range Comparisons


Uplink Link Budget Methodology (1/8)

MAPL Calculation (1/3: R’99)

MAPLMAPL Calculation (Release 99)Calculation (Release 99)

Aim: used to derive Cell Range

Depends on:

• UL dimensioning service i (usually CS64)

• Propagation environment

• UE and Node-B performances

• Shadowing Margin, Fast Fading Margin, UL Interference Margin

MarginceInterferenULMarginFadingFastMarginShadowing

LossCablesGainAntBTSLossnPenetratioLossBody

iySensitivitNodeBPowerTxMaxUEiMAPL

−−−−+−−

−=.

)(.)(

UE

Max

.T

xP

ow

er

BodyLoss BTS

AntennaGain

PenetrationLoss

No

de-

B S

ensi

tivi

ty(

depe

nds

on U

L se

rvic

e i )

Max. Allowable air interface Path Loss (MAPL)


Shadowing Margin

Uplink Interference Margin

Cables Loss

Fast Fading Margin



MAPL Calculation (2/3: Impact of HSDPA)

MAPLMAPL Calculation (Impact of HSDPA)Calculation (Impact of HSDPA)

Mandatory channels for data transfer on HSDPA:

Presence of HS-DPCCH impacts MAPL:

UE transferring on HSDPA must feed back CQI and ACK/NACK to Node-B on HS-DPCCH

UE available Tx power fordimensioning UL service i diminishes

MAPL diminishes

+++

=

∆

222

22

0

log10hsdc

dc

Target

bN

EUL

βββββ

Handled in the UL link budget as an increase in UL Eb/N0 Target (Vs. w/o HS-DPCCH case):



MAPL Calculation (3/3: HSUPA)

MAPLMAPL Calculation (HSUPA)Calculation (HSUPA)

Cell Range definition:

� R’99: Cell Range derived assuming a specific UL R’99 dimensioning service i

� HSUPA: Cell Range may be derived assuming either:

– a specific UL R’99 dimensioning service i

– a specific E-DCH user throughput at cell edge r

HSUPA Ec/N0 according to E-DCH user throughput at cell edge r:

)()(0

iNENoiseThermalNodeBiySensitivitNodeB

Target

c+=

1. For several E-TFCs, E-DPDCHs Ec/N0 is

given by L1 curves:

E-DPDCHs Ec/N0

E-DCH

User Throughput

2. For each E-TFC, HSUPA Ec/N0 is derived

from E-DPDCHs Ec/N0 :

3. Criterion for choice of E-TFC:

E-TFC giving best Ec/N0

E-TFC giving best BLER 1Tx

0

2

22222

0

NEDPDCHsE

n

nN

EHSUPA

c

eded

hscdeceded

Target

c

×

⋅++++⋅=

ββββββ

r

or



Shadowing Margin

Shadowing MarginShadowing Margin

Aim: Compensation of Shadowing, i.e. variation in signal strength due to obstacles

modeled by a Log-Normal law, for mobiles close to cell edge.

Value computed so that UL service i can be statistically offered within AR% of cell

area (AR: Area Reliability).

Calculation Method:

1. Assumption on Log-Normal law Stand. Dev. :

2. Jakes Formula for Soft Handover with 2 servers (R’99)Inputs: σShad, AR, Attenuation Exponent, Correlation coeff. between Shadowing of the 2 legs

HSUPA-specific: Jakes Formula for 2 servers without SHO(SHO not supported in Alcatel-Lucent UA5.0 Release)

22nPenetratioIndoorOutdoorShadShad σσσ +=

UE

Max

.T

xP

ow

er

BodyLoss BTS

AntennaGain

PenetrationLoss

No

de-

B S

ensi

tivi

ty(

depe

nds

on U

L se

rvic

e i )


Shadowing Margin

Shadowing Margin


Cables Loss

Fast Fading Margin



Fast Fading Margin

Fast Fading MarginFast Fading Margin

Aim: Compensation of Fast Fading, i.e. variation in signal strength due to

multi-path Rayleigh channel profile, for a mobile close to cell edge.

Value computed so that a mobile at cell edge can do efficient Power Control,

i.e. combat the Fast Fading.

Calculation Method:

Currently, same calculation method for R’99 and HSUPA

UE

Max

.T

xP

ow

er

BodyLoss BTS

AntennaGain

PenetrationLoss

No

de-

B S

ensi

tivi

ty(

depe

nds

on U

L se

rvic

e i )


Shadowing Margin


Cables Loss

Fast Fading Margin

Fast Fading Margin

( ) ( )OnTPCNEULOffTPCN

EULMarginFadingFastTarget

b

Target

b =−==00



Uplink Interference Margin (1/2)

Uplink Interference MarginUplink Interference Margin

Aim: Compensation of interference generated by other mobiles on the uplink.

Value computed for each UL service i so that i transmitted by a mobile can be

received at Node-B with sufficient SINR even at maximum UL Cell Load.

Calculation Method: )()(. iRiseNoiseULUserRiseNoiseULTotaliMarginInterfUL −=

−=∆

LoadCellULNoiseThermalBTS

ceInterferenULTotal

1

1

NoiseThermalBTS

PowerRxUser

( )[ ]).(.)(1log10)(. iPRxUserInterfULTotaliPowerRxUserNRULTotaliMarginInterfUL dBdB −+−=

+−= )(1log10)(0

iNERiseNoiseULTotaliMarginceInterferenUL

Target

cdBdB

UE

Max

.T

xP

ow

er

BodyLoss BTS

AntennaGain

PenetrationLoss

No

de-

B S

ensi

tivi

ty(

depe

nds

on U

L se

rvic

e i )


Shadowing Margin



Cables Loss

Fast Fading Margin



Uplink Interference Margin (2/2)

Reminder:

Total UL Noise Rise value setting in the link budget:

Set to the maximum allowed value: Max. UL Noise Rise

Set according to an iterative process:

� Functional point between {Cell Range = UL Link Budget( Total UL NR )} and

{Total UL NR = Traffic ModelTraffic Model( Cell Range )}

� Total UL Noise Rise<Max. UL Noise Rise must be true

Max. UL Noise Rise is set by below UTRAN parameters:

� Limit applied on R’99 traffic only: rtwpMaxCellLoadNonEdch

(Default in UA5.0: 50%)

� Limit applied on total UL traffic (R’99+HSUPA): totalRotMax

(Default in UA5.0: 6dB)

•Number of subscribers per km2

•Call Profile•Grade of Service (GoS) for each UL service

+−= )(1log10)(0

iNERiseNoiseULTotaliMarginceInterferenUL

Target

cdBdB

or



Cell Range Calculation

Cell RangeCell Range Calculation basing onCalculation basing on MAPLMAPL

Relationship Cell Range ↔ MAPL:

� 2100 MHz: COST-Hata propagation model

� 900 MHz: Okumura-Hata propagation model

Site Coverage for 3-sector case (surface covered by 1 Node-B):

]dB[.])m[log(])m[.log(55.69.44(

][..])m[.log(82.13])MHz[log(9.333.46]dB[

FactorCorrtEnvironmenkdHeightAntBTS

dBFactorCorrHeightAntUEHeightAntBTSfLossPath

+⋅−+−−+=

]dB[.])m[log(])m[.log(55.69.44(

][..])m[.log(82.13])MHz[log(16.2655.69]dB[

FactorCorrtEnvironmenkdHeightAntBTS

dBFactorCorrHeightAntUEHeightAntBTSfLossPath

+⋅−+−−+=

UE

Max

.T

xP

ow

er

BodyLoss BTS

AntennaGain

PenetrationLoss

No

de-

B S

ensi

tivi

ty(

depe

nds

on U

L se

rvic

e i )



Shadowing Margin


Cables Loss

Fast Fading Margin

223 ]km[8

39]km[ RangeCellCoverageSite Sectors ×=



Tower Mounted Amplifier (TMA) Benefits and Drawbacks

TMA Aim: Reduce the impact of Cables Loss in the UL ⇒ increase Cell Range

TMA handling in Alcatel-Lucent link budget:

� UL:

� Cables Loss = 0.4dB (jumper before TMA),

� Friis Formula for the Noise Figure of {TMA, cables after TMA, BTS}

� DL: +0.8dB on Cables Loss compared to without TMA case

(1 additional jumper + TMA insertion loss)

BTS Antenna Gain

Cables Loss

Without TMA

Nod

e-B

S

ensi

tivity

BTS Antenna Gain

Cables Loss with TMA

With TMA

Nod

e-B

S

ensi

tivity

TMA impact on the UL:

Simplifiedvision


Cell Range Comparisons (1/2)

Dense Urban Environment

Main Assumptions:

� Channel Profile = “Pedestrian A 3km/h”

� HS-DPCCH impact included in UL R’99 services Eb/N0

� E-TFC chosen according to best Ec/N0 criterion

� Penetration Loss = 18dB, Hata Env. Corr. Factor = 0dB, TMA = On

� UE Max. Tx Power = 21dBm for all services (conservative)

0.2

0.3

0.4

0.5

0.6

0.7

0 1 2 3 4 5 6 7 8 9Max. UL Noise Rise [dB]

Cel

l Ran

ge [

km]

DCH 128E-DCH 128DCH 384E-DCH 384E-DCH 1024


Cell Range Comparisons (2/2)

Suburban Environment

Main Assumptions:


� HS-DPCCH impact included in UL R’99 services Eb/N0

� E-TFC chosen according to best Ec/N0 criterion

� Penetration Loss=10dB, Hata Env. Corr. Factor = -12dB, TMA = On

� UE Max. Tx Power = 21dBm for all services (conservative)

0.7

0.9

1.1

1.3

1.5

1.7

1.9

2.1

2.3

0 1 2 3 4 5 6 7 8 9Max. UL Noise Rise [dB]

Cel

l Ran

ge [

km]

DCH 128E-DCH 128DCH 384E-DCH 384E-DCH 1024


Agenda





2UMTS Downlink Link Budget

Methodology, Impact of HSUPA DL channels


Downlink Link Budget Methodology (1/3)

Downlink Maximum Air Path Loss Calculation

Downlink Maximum Air Path LossDownlink Maximum Air Path Loss

DL air interface path loss at the cell edge,

i.e. for Cell Range derived from UL link budget

Aim: used to derive Downlink Maximum Total Path Loss

Calculation Method: COST-Hata-1( Cell Range, DL f )

≡ MAPL + Frequency Shift( DL f – UL f )

Depends on:

� R’99: UL R’99 dimensioning service i

� HSUPA: i or specific E-DCH user throughput at cell edge r

BTS Ant. Gain DL Max. Total Path LossCables Loss

DL Max. Air Path Loss


PenetrationLoss

Shadowing Margin Fast Fading

MarginReq

uir

ed D

L

Use

r T

xP

ow

er(

depe

nds

on

DL

serv

ice

j ) Body Loss

UE

Sen

siti

vity

( de

pend

s on

DL

serv

ice

j )



Downlink Maximum Total Path Loss Calculation

Downlink Maximum Total Path LossDownlink Maximum Total Path Loss

DL total path loss at the cell edge, from BTS PA to UE

Aim: used to derive Required DL User Tx Power, HSDPA throughput…

Calculation Method:

Remark: DL Max. Total PL does not take into account any DL interference margin.

Indeed, DL interferences are directly taken into account in

the following formula giving Required DL User Tx Power.

BTS Ant. GainDL Max. Total Path Loss

DL Max. Total Path LossCables Loss


PenetrationLoss


MarginReq

uir

ed D

L

Use

r T

xP

ow

er(

depe

nds

on

DL

serv

ice

j ) Body Loss

UE

Sen

siti

vity

( de

pend

s on

DL

serv

ice

j )

MarginFadingFastMarginShadowing

LossBodyLossPeneGainAntBTSLossCable

PLAirMaxDLPLTotalMaxDL

++++−+

=..

..



Required Downlink User Tx Power

Required Downlink User Required Downlink User TxTx PowerPower

Required transmit power at BTS PA so that DL R’99 service j can be received with sufficient SINR by a mobile at cell edge.

Allows to know if DL coverage can be assured at cell edge for service j,

by comparing with maxDlTxPower(j), i.e. max. power allowable for j per user.

Calculation Method:

BTS Ant. Gain DL Max. Total Path LossCables Loss


PenetrationLoss


MarginReq

uir

ed D

L

Use

r T

xP

ow

er

Req

uir

ed D

L

Use

r T

xP

ow

er(

depe

nds

on

DL

serv

ice

j ) Body Loss

UE

Sen

siti

vity

( de

pend

s on

DL

serv

ice

j )

1

0)(

..)(

)(. −

+

×+×+=

jNEDLOF

PLTotalMaxDLNoiseThUEPAOFIi

IeDL

jPowerTxUserDLReq

Target

c

edgecell

Ii : Intra-cell interference(before despreading, includes own signal)

OVSF Codes Orthogonality Factor(depends on channel profile)

Ie : Extra-cell interference


Power Available for HSDPA (1/2)

Computation Method in UA5.0 Release, for Shared Carrier scenario

Power Available for HSDPAPower Available for HSDPA (HS-DSCH+HS-SCCH, all HSDPA users in cell)

Computation Method in UA5.0 Release:

� Tx Power for each common control channel: set relatively to CPICH Tx Power

� CPICH Tx Power : set according to CPICH Ec/I0 Target , Cell Range,

Area Reliability, environment parameters

� P. HSUPA : room power reserved for HSUPA DL channels. Constant, tunable.

� P. Non HSDPA : transmit power for non-HSDPA traffic, i.e. R’99 traffic, common control channels and HSUPA downlink channels.

Updated within Node-B every 100ms.

� DCH Margin: room power for DCH used to prevent fast increase of DCH power

due to Power Control. Proportional to (P. Non HSDPA – CPICH Tx Power)

{ }MarginDCHHSDPANonPPAHSUPAPCCCPMarginSHOPA

HSDPAforAvailablePowerDL

−−−−−= .,..Min

RNC view Node-B view


Power Available for HSDPA (2/2)

Impact of HSUPA Downlink Channels

Power for HSUPA Downlink Channels – Link Budget model:

DL HSUPA Tx Power is assumed constant:

� ααααE-AGCH : coefficient (0~1) chosen according to supposed amount of HSUPA traffic.

Assumption: only 1 absolute grant sent at one time.

Default value in Link Budget: 1

� E-AGCH Tx Power : Tx power for 1 E-AGCH channel.

UTRAN default value: CPICH Tx Power - 2.5dB

� nE-HICH : Average number of signatures used on E-HICH

Default value in Link Budget: 2

� E-HICH Tx Power : Tx power per signature of E-HICH.

E-HICH channel Tx power is proportional to #signatures used.

UTRAN default value: CPICH Tx Power – 18.6dB

PowerTxHICHEnPowerTxAGCHEPowerTxHSUPADL HICHEAGCHE ×+×= α

E-RGCH not supported in UA5.0


Agenda





3Capacity and Throughput Calculation Basics

Method presented: calculation via formulas/static simulation


Pole Capacity:

Maximum theoretical number of active users on the UL supported per cell,

when no limit on UE Max. Tx Power and Max. UL Noise Rise

UL Cell Capacity:

Max. # active users on the UL supported per cell

(all using same UL service i)

Uplink Capacity Calculation (1/2)

Mono Service

ULie

i

II

IFR

+=

⋅+=

SHOTarget

c

Pole

GiNEULiAF

FRiN

)()(

1)(

0

LoadCellULiNiCapacityCellUL Pole ⋅= )()(

Frequency Reuse Efficiency

Soft Handover Gain on capacity(not considered for HSUPA)channel Activity Factor

(only for Speech service)

Assumed equal to the maximum allowed value, i.e. 1-1 / Max UL Noise Rise

or

Set according to an iterative process, thanks toTraffic ModelTraffic Model

May also be Ec/N0

Target for E-DCH with a specificthroughput r


UL Cell Capacity in Traffic Mix:

Maximum number of users (including non-active users) on the UL

supported per cell, assuming a specific Call Profile

Uplink Capacity Calculation (2/2)

Traffic Mix

∑=

=servicesUL

i Pole

UL

iN

i

LoadCellULMixTrafficinCapacityCellUL

#

1 )(

)(α

Average user throughput in Busy Hour for UL service ias given in the Call Profile

∑=

=servicesUL

k

UL

iR

kthroughputCP

iR

ithroughputCP

i#

1 )(

)(

)(

)(

)(αRate for service i(e.g. 64kbps for CS64)

Formula mayaccount for some UL services defined asE-DCH with a specificthroughput r


Asymptotic Capacity:

Maximum theoretical number of active users on the DL supported per cell,

when no limit on BTS Power Amplifier (all using same DL service j)

DL Cell Capacity in Traffic Mix:

(HSDPA traffic not present, analytic calculation)

Max. #active users on the DL supported per cell

Dowlink Capacity Calculation

OFIi

IeDL

GiNEDLOF

iAFjN

mean

SHOTarget

c

Asymp

+

++=

−1

0)(

)(

1)(

OFIi

IeDL

PLTotalMeanDLNoiseThUEPA

PowerTxCCCPA

mean

+

×+

−.

∑=

=servicesDL

j Asymp

DL

jN

j

LoadCellDLMixTrafficinCapacityCellDL

#

1 )(

)(α


Power Available for HS-DSCH

HS-DSCH Rx Ec/N0

DistanceServing Node-B↔↔↔↔UE

HSDPA UE Category

HSDPA User Throughput

CQI reported

HSDPA Throughput Computation via Static Simulation (1/2)

UE SpeedChannel Profile

DL Total Path Loss

Shadowing at UE

BTS Ant. Diagram

HSDPA User ThroughputHSDPA User Throughput Map Computation via Static SimulationMap Computation via Static Simulation

1. Generate DL Total Path Loss map for each cell.

For each location {x,y} , find the serving cell.

2. Calculate Power Available for HS-DSCH

For each location {x,y} :

3. Calculate HS-DSCH Rx Ec/N0

4. Calculate CQI reported by the mobile

5. Calculate HSDPA User Throughput

[ ]),,(Min)ˆ,,(

,ˆ),(

cyxPLcyxPL

cyxCellServing

==

a)

b) Estimate and subtract HS-SCCH Tx Power

−−−−−

=MarginDCHHSDPANonPPA

HSUPAPCCCPMarginSHOPA

HSDPAforAvailablePowerDL

.

,..Min


Power Available for HS-DSCH

HS-DSCH Rx Ec/N0


HSDPA UE Category



CQI reported

CQI reported

HSDPA Throughput Computation via Static Simulation (2/2)

UE SpeedChannel Profile

DL Total Path Loss

Shadowing at UE

BTS Ant. Diagram

HSDPA User ThroughputHSDPA User Throughput Map Computation via Static SimulationMap Computation via Static Simulation

4. Calculate CQI reported by the mobile:

5. Calculate HSDPA User Throughput:

[dB]0N

ERxDSCHHSreportedCQI cspeed += β

13.3120 km/h

14.350 km/h

15.53 km/h

ββββspeedUE Speed

3

2

# HS-PDSCH(s)

QPSK

QPSK

Modulation

432 kbps31262 b10

288 kbps2931 b9

RLC Throughput# MAC-hs PDU(s)per TB

TransportBlock Size

CQI

CQI Table for

UE Category 6

……

Derived from TBS, MAC-d PDU size (=336b),MAC-hs header size (21b)

Derived assuming BLER 1Tx=10%


UL Noise Rise Available for user

E-DCHRx Ec/N0


HSDPA UE Category

E-DCH User Throughput

E-TFC

HSUPA Throughput Computation via Static Simulation

UE Speed

Max. ULNoise Rise(totalRotMax)

UL Total Path Loss

Shadowing at UE

BTS Ant. Diagram

HSUPA User ThroughputHSUPA User Throughput Map Computation via Static SimulationMap Computation via Static Simulation

1. Generate UL Total Path Loss map for each cell.

For each location {x,y} , find the serving cell.

2. Calculate UL Noise Rise Available for User

For each location {x,y} :

3. Calculate E-DCH Rx Ec/N0

4. Derive E-TFC

5. Calculate E-DCH User Throughput

Channel Profile

usersotherRiseNoiseUL

xtotalRotMa

−

E-DPDCHs Ec/N0

E-DCH

User Throughput


HSUPA Throughput Computation via Static Simulation (1/2)

User Throughput Map

Main Assumptions:

� HSUPA dedicated carrier (no R’99 UL traffic)



� Shadowing standard deviation = 8dB

� UE: Max. Tx Power = 21dBm, HSUPA Category 3

CellRange: +20%

Cell Range dimensionedon E-DCH 128


HSUPA Throughput Computation via Static Simulation (2/2)

User Throughput Vs. Distance from Site

Main Assumptions:

� Shared carrier R’99/HSUPA



� Shadowing standard deviation = 8dB

� UE: Max. Tx Power = 21dBm, HSUPA Category 3

•0 •100 •200 •300 •400 •500 •600•700

•800

•900

•1000

•1100

•1200

•1300

•Distance from Serving NodeB [m]

•E-D

CH

MA

C-e

Use

r T

hrou

ghpu

t[kb

ps]

•

R’99 UL Cell Load = 50% * Max. UL Cell Load

No R’99 UL traffic

Cell Range = 450m

Cell Range = 540m

Cell Range: +20%


Presentation Summary

UMTS Link Budget methodology:

� Uplink: Cell Range derivation based on specific UL dimensioning service

� Downlink:

� Calculation for each DL service of required power necessary to reach cell edge

� Comparison with maximum allowed power for this DL service

UMTS Link Budget tool usage:

� Main objective: derive Cell Range assuming a dimensioning UL service

� Other features: UL and DL Capacity calculation via formulas

Gives an idea of capacity without running any simulation

� Gives inputs for Radio Dimensioning and Cell Planning

� Used to study impact of features on RF aspects


www.alcatel-lucent.com

Alcatel-Lucent UMTS Link Budget Methodology v1.0

Documents

ul link budget

link budget methodology

margin7 hsupa link budget

site4 hsupa link budget

ul dimensioning service

capacity calculation

throughput map throughput

cell range derivation