Wcdma Radio Network Planning And Optimization

WCDMA Radio Network Planning and Optimization

Song Pengpeng

Presentation Title — 2 All rights reserved © 2004

Contents

> WCDMA Fundamentals(including link budget fundamentals)

> Radio Resource Utilization

> Coverage and Capacity issues

> Cell deployment

> WCDMA Radio Network Planning(including WCDMA-GSM Co-planning issues )

> Co-existing TDD & FDD modes


WCDMA Fundamentals

> WCDMA network infrastructure

> WCDMA radio interface protocol architecture

> WCDMA link level characteristics & indicators

> WCDMA link budget analysis


WCDMA Fundamentals

> WCDMA Network infrastructure

I u

I ur

I ub I ub

Uu

MSC

RNCRNC

NodeB NodeB NodeB NodeB

UE

CN

UTRAN

I u

I ub I ub

UEUE UE

Data General Data GeneralData General


WCDMA Fundamentals

> WCDMA Radio Interface protocol architecture

Radi o Resource ControlSubl ayer(RRC)

Medi a Access Control Subl ayer (MAC)

Physi cal l ayer (PHY)

Packet DataConvergence

Protocol (PDCP)

Radi o Li nkControl

Subl ayer(RLC)RLC RLC RLC RLC

Transport Channel s

Logi cal Channel s

Si gnal l i ngRadi o Bearers

Radi o Bearers

Layer 3

Layer 2

Layer 1


WCDMA Fundamentals

> Mapping between Trch and PHY channelsTransport Channels

DCH

RACH

CPCH

BCH

FACH

PCH

Physical Channels

Dedicated Physical Data Channel (DPDCH)

Dedicated Physical Control Channel (DPCCH)

Physical Random Access Channel (PRACH)

Physical Common Packet Channel (PCPCH)

Common Pilot Channel (CPICH)

Primary Common Control Physical Channel (P -CCPCH)

Secondary Common Control Physical Channel (S -CCPCH)

Synchronisation Channel (SCH)

Acquisition Indicator Channel (AICH)

Access Preamble Acquisition Indicator Channel (AP-AICH)

Paging Indicator Channel (PICH)

CPCH Status Indicator Channel (CSICH)

Collision-Detection/Channel-Assignment Indicator

Channel (CD/CA-ICH)

DSCH Physical Downlink Shared Channel (PDSCH)

HS-DSCH-related Shared Control Channel (HS-SCCH)

HS-DSCH High Speed Physical Downlink Shared Channel (HS-PDSCH)

Dedicated Physical Control Channel (uplink) for HS-DSCH (HS-DPCCH)

NodeB

UE

Si gnal i ng and ControlChannel s, e. g.

BCH, PCH, FACH, RACH. . .

User data transmi ssi on, DCH, DSCH, HS-DSCH, CPCH. . .


WCDMA Fundamentals

WCDMA link level indicators

indicators Formularization Comments

BLER Average block error rate calculated for the transport blocksBER

Information bit error rateR User information bit rate

Eb/No

Uplink:

Downlink:Energy per bit divided by noise spectral density(including interference

power density)

Ec/Io(Eb/No) divided by

processing gainThe received chip energy relative to the total power spectral density;

always used on CPICH,AICH and PICH.

Ec/IorThe transmitted energy per chip on a chosen channel relative to the

total transmitted power spectral density at the base station.

IOther-to-own-cell received power ratio

G(Geometry factor)

Mostly used in downlink, G reflects the distance of the MS from the BSantenna. Atypical range is from –3 dB to 20 dB, where –3 dB is for the

cell edge.

Average Power RiseThe difference between the average transmitted power and the average

received power in low multi-path diversity channelsNoise Rise The ratio of the total received wideband power to the noise power.

Power Controlheadroom

(Average requiredreceived Eb/Io without fast PC)-

(average required receivedEb/Io with fast PC) Also referred as “TPC headroom” or “multipath fading margin”

Macro DiversityCombining Gain

The reduction of the required Eb/No per link in soft or softer handoverwhen compared to the situation with one radio link only.

I

P

R

W

N

E rxb 0

Nothown

rxb

PII

P

R

W

N

E

)1(0

own

oth

I

Ii

Noth

own

PI

IG

Parameters WCDMAChip rate 3.84 Mcps

Frame length 10 or 2 ms

ModulationDownlink: QPSK;

Uplink: HPSKBandwidth 5 MHz

VocoderAlgebraic Code Excited

Linear Prediction Coder(ACELP)Base synchronization AsynchronizationPower control rate 1500 Hz

Cell identificationUnique scrambling code (Gold code)

Channelization codeOVSF code

WCDMA parameters


WCDMA Radio Network Planning---Example of link budget analysis

> RF link budget components:


WCDMA Radio Network Planning---Example of link budget analysis

Allowed propagation lossfor cell range[dB] 141.9 v=r-s+t-u

Transmitter(mobile)Max. Tx power[dBm] 21 aMobile antenna gain[dBi] 0 bBody loss[dB] 3 cEquivalent IsotropicRadiated power(EIRP)[dBm] 18 d=a+b-c

Receiver(base station)Thermal noise density[dBm/Hz] -174 eBase station receivernoise figure[dB] 5 fReceiver noise density[dBm/Hz] -169 g=e+fReceiver noise power[dBm] -103.2 h=g+10*log(3840000)

Interference margin[dB] 3 IReceiver interferencepower[dBm] -103.2 j=10*log(10^((h+i)/10)-10^(h/10))Total effectve noise +interference [dBm] -100.2 k=10*log(10^(h/10)+10^(j/10))Processing gain[dB] 25 l=10*log(3840/12.2)Required Eb/No[dB] 5 mReceiver sensitivity[dBm] -120.2 n=m-l+kBase station antennagain[dBi] 18 o

Max_path_loss=Ptx_EIRP - Prx_receiver_sensitivity -Lrx_cable+ Grx_antenna

Cable loss in the basestation[dB] 2 pFast fading margin[dB] 0 qMax.path loss[dB] 154.2 r=d-n+o-p-q

Allowed_propagation_loss=Max_path_loss -Log_normal_fading_margin +soft_handover_margin -in_car_loss

Example of RLB for 12.2 kbps voice service(uplink,120km/h,in-car users,VA channel with soft handover)Example of RLB for 12.2 kbps voice service(uplink,120km/h,in-car users,VA channel with soft handover)Example of RLB for 12.2 kbps voice service(uplink,120km/h,in-car users,VA channel with soft handover)Example of RLB for 12.2 kbps voice service(uplink,120km/h,in-car users,VA channel with soft handover)

Coverage probability[%] 95Log normal fadingconstant[dB] 7Propagation model exponent 3.52Log normal fading margin[dB] 7.3 sSoft handover gain[dB] 3 tIn-car loss[dB] 8 u

(*) *“modeling the impact of the fast power control on the WCDMA uplink”, sipila,K., Laiho-Steffens,J.,Jasberg,M. and Wacker.A, Proc VTC99’ Spring Huston,Texas,May 1999 pp.1266-1270(*) *“modeling the impact of the fast power control on the WCDMA uplink”, sipila,K., Laiho-Steffens,J.,Jasberg,M. and Wacker.A, Proc VTC99’ Spring Huston,Texas,May 1999 pp.1266-1270

A headroom for mobile station to maintainadequate closed loop fast power control. Thisapplies especially to slow-moving pedestrianmobiles.Typical values are 2.0-5.0 dB for slow-moving mobiles(*)

handovers give a gin against slow fading byreducing the required log-normal fading margin;italso gives an additional macro diversity gainagainst fast fading by reducing the requiredEb/No due to the effect of macro diversitycombining.

the margin required to provide a specifiedcoverage availability over the individual cells.For a 95% coverage with a standard shadowingdeviation of 6.0dB and path loss model withn=3.6 we need a shadowing margin ofapproximately 6.0dB

Closely related with the loading of the cell whichsubsequently affects the coverage. For coverage-limited cases a smaller interference margin issuggested,while in capacity-limited cases a largerinterference margin should be used. Typical valuefor the interference margin in the coverage-limitedcases are 1.0-3.0 dB corresponding to 20-50%loading.


HandoverControl

Power Control

ResourceManager

Admissioncontrol

Load control

Packet datascheduling

Congestion Control

Radio Resource Management

RADIO RESOURCE UTILIZATION

To adjust the transmit powers in upilnk and downlink to the minimum level required to enshure the demanded QoS

To adjust the transmit powers in upilnk and downlink to the minimum level required to enshure the demanded QoS

Takes care that a connected user is handed over from one cell to another as he moves through the coverage area of a mobile network.

Takes care that a connected user is handed over from one cell to another as he moves through the coverage area of a mobile network.

To ensure that the network stays within the planned condition

To ensure that the network stays within the planned condition

Let users set up or reconfigure a radio access bearer(RAB) only if these would not overload the system and if the necessary resources are available.

Let users set up or reconfigure a radio access bearer(RAB) only if these would not overload the system and if the necessary resources are available.

Takes care that a system temporarily going into overload is returned to a non-overloaded situation.

Takes care that a system temporarily going into overload is returned to a non-overloaded situation.

To handle all non-realtime traffic,allocate optimum bit rates and schedule transmission of the packet data, keeping the required QoS in terms of throughput and delays.

To handle all non-realtime traffic,allocate optimum bit rates and schedule transmission of the packet data, keeping the required QoS in terms of throughput and delays.

To control the physical and logical radio resources under one RNC;to coordinate the usage of the available hardware resouces and to manage the code tree.

To control the physical and logical radio resources under one RNC;to coordinate the usage of the available hardware resouces and to manage the code tree.

> Basic RRM functions

* Power Control

* Handover Control

* Congestion Control

* Resource Management


RADIO RESOURCE UTILIZATION---power control(1)

> UMTS Power Control(PC) summary


RADIO RESOURCE UTILIZATION---power control(2)

> Uplink/Downlink inner- and outer- loop power control

NBAP: initia

l target SIR,DL initia

l/max/min

RL power, DL TPC_step,DPC_MODE

NodeB

UE

SRNC

RRC:DL target BLER, U

L gain factors, UL TPC_step, PC algorith

m, UL RM values, D

PC_MODE

RRC: actual BLER,P-CPICH Ec/Io,P-CPICH RSCP, path loss,

traffic+UE internal m

eans

PC on DPCCH + DPDCHs

UL/DL TPC command on DPCCH(Inner lo

op PC)

DCH-FP(10-100Hz):UL CRC and QE

UL actual target SIR

Iub

Uu

SIR estimates Vs target SirUL TPC commands

DL outer loop PCSIR_step=f(BLER or BER)

SIR target management

SIR estimate vs. target SIR DL TPC commands

UL outer loop PCSIR_step=f(BLER or BER)

SIR target management

MDC and splitting


RADIO RESOURCE UTILIZATION---handover control

> Soft-Handover:Example of Soft Handover Algorithm

Event 1A: A P-CPICH enters the reporting range Event 1A: A P-CPICH enters the reporting range

)2(log10)1(log10log10 11101

1010 aaBest

N

iinew HRMWMWM

A

Event 1B: A P-CPICH leaves the reporting range Event 1B: A P-CPICH leaves the reporting range

)2(log10)1(log10log10 11101

1010 bbBest

N

iiold HRMWMWM

A

Event 1C: A non-active PCPICH becomes better than an active one

Event 1D: change of best cell. Reporting event is triggered when any P-CPICH in the reporting range becomes better than the current bet one plus an optional hysteresis value.

Event 1E: A P-CPICH becomes better than an absolute threshold plus an optional hysteresis value.

Event 1F: A P-CPICH becomes worse than an absolute threshold minus an optional hysteresis value.

Event 1C: A non-active PCPICH becomes better than an active one

Event 1D: change of best cell. Reporting event is triggered when any P-CPICH in the reporting range becomes better than the current bet one plus an optional hysteresis value.

Event 1E: A P-CPICH becomes better than an absolute threshold plus an optional hysteresis value.

Event 1F: A P-CPICH becomes worse than an absolute threshold minus an optional hysteresis value.

Addition windowAddition window

drop windowdrop window

AS_Th – AS_Th_HystAs_Rep_Hyst

As_Th + As_Th_Hyst

Cell 1 Connected

Event 1A Add Cell 2

Event 1C Replace Cell 1 with Cell 3

Event 1B Remove Cell 3

CPICH 1

CPICH 2

CPICH 3

Time

MeasurementQuantity

T T T

NodeB 1

SRNC

I ub Macro Di versi tycombi ni ng

NodeB 2

I ub

TPC command1

transmi ssi on

l i nk 1

UE i n SHO

TPC

comm

and2

tran

smi s

sion

l ink

2


RADIO RESOURCE UTILIZATION---PC and SHO conclusion

> Bonding of SHO and PC(based on the fact that SHO gain is dependent on the PC efficiency)

• SHO gain depends on the type of channel and the degree of PC imperfection.It is usually higher with imperfect PC.

• SHO diversity can reduce the PC headroom,thus improving the coverage.• The transmit and receive power differences as a result of SHO

measurement errors and SHO windows can affect the PC error rate in uplink,reducing the uplink SHO gains.

• In uplink, SHO gain is translated into a decrease in the outer-loop PC’s Eb/No target.


RADIO RESOURCE UTILIZATION---congestion control

> Air interface load definition(load control principles)• Uplink

• Wideband power-based uplink loading where

• Throughput-based uplink loading• Downlink

• Wideband power-based downlink loading

• Throughput-based downlink loading

or

rxTotal

othownUL P

II

NothownrxTotal PIIp

k

kkk

UL i

RW

)1(1

1

maxtx

rxTotoalDL P

P

max

1

R

RN

kk

DL

N

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kkkDLDL W

Ri

1

)(])1[(


RADIO RESOURCE UTILIZATION---congestion control (cont’d) > Congestion control---keep the air interface load

under predefined thresholds• Admission control---handling all the new traffic• Load control---managing the situation when

system load has exceeded the threshold• Packet scheduling---handling all the non-real-

time traffic

Admi ssi oncontrol

Load control

Packet dataschedul i ng

Congesti on Control

> Admission control• Wideband power-based admission control

– For uplink, an RT bearer will be admitted if where and

– For downlink, an RT bearer will be admitted if

• Throughput-based admission control– For uplink, it follows – For downlink, it follows

etrxTrxNC PIP arg

rxOffsetetrxTrxTotoal PPP argLP

I rxTotal

1

RW

L1

1

ettxTtxNC PPP argtxOffsetettxTtxTotal PPP arg

LthresholdUoldUL L LthresholdDoldDL L


RADIO RESOURCE UTILIZATION---congestion control (cont’d)

> Packet scheduling• Time division scheduling• Code division scheduling

Packet schedul i ng al gori thm

Process Capaci ty requests

Cal cul ate l oad budget forpacket schedul i ng

Load bel ow targetl evel ?

Overl oad threshol dexceeded?

I ncrease l oadi ng Decrease l oadi ng

Al l ocate/ modi fy/ rel easeradi o resources

Yes No

Yes

No


RADIO RESOURCE UTILIZATION---Code Planning

> Code planning• Code allocation is under the control of RNC.• Code tree may become “fragmented” and code

reshuffling is needed(arranged by RNC).

> Code allocation• Scrambling and spreading code allocation for uplink(by

UTRAN)• Scrambling and spreading code allocation for downlink

• Downlink channelisation code allocation (by UTRAN)• Downlink scrambling code planning

• 512 scrambling codes subdivided into 64 groups each of eight codes


RRM optimization --- SHO optimization(1)

> Addition window optimization• Determines the relative difference of the cells

at the MS end that are to be included in the active set

• Optimized so that only the relevant cells are in the active set

Addi ti onwi ndow

Too wi deSHO area

Too smal lSHO area

Unnecessarybranch

addi t i on

MRC gai nreducti on

I ncreasedSHO

overhead

Reduced DLcapaci ty

Degradedperformancedue to toohi gh l evel

di ff erence ofthe si gnal s

i n AS

I ncreasedBS and MSTx Power

Reduced DLand UL

capaci ty

Frequent ASupdates

Rel evantcel l s removed

f rom AS

Reduced ULcapaci ty

I ncreasi ngsi gnal l i ngoverhead

I ncreasedTx powers

Reduced UL/DL capaci ty

too hi gh

too l ow



> Drop window optimization• Slightly larger than the addition window

dropwi ndow

Unnecessarybranches

stay i n AS

FrequentHOs

Too l argeSHO

overhead

I ncreasedsi gnal i ngoverhead



i n AS

I ncreased BSand MS Tx

Power

I ncreased BSTx power

Rel evantcel l s removed

f rom AS

I ncreasedTx powers

Reduced UL/DL capaci ty

too hi gh

too l ow

Reduced DLcapaci ty

I ncreasedMS Tx power

Reduced ULcapaci ty

too l ow

Frequent and delayed Hos (cells ping-pong in the

active set)

Frequent and delayed Hos (cells ping-pong in the

active set)



> Replacement window optimization• Determines the relative threshold for MS to trigger the reporting Event 1C.

– Too high: slow branch replacement and thus non-optimal active set– Too low: ping-pong effect with unnecessary SHOs

repl acmentwi ndow

Acti vesetsubopti mal

Exceuti on ofunnecessary

HOs

MS Tx poweri ncrease

I ncreasedsi gnal i ngoverhead

BS Tx poweri ncrease

DL l oadi ncrease

too hi gh

too l ow

Reduced cal lsetup success

rate

UL l oadi ncrease

I ncreasedcal l drop orbl ock rate Reduced DL/ UL

total cel ltraffi c



> Maximum active set size optimization

Max ASsi ze

Possi bl eunnecessary

branch addi t i on

Preventnecessary sof t

HO branchaddi t i on

Requi rehi gher Tx

power to a MS

I ncreasedBS Tx power

Reduced DLcapaci ty



i n AS

Reduced ULcapaci ty

Requi re hi gherTx power f rom

a MS

Degraded DLBLER

performance

Degraded ULBLER

performance

I ncreasedcal l drop/bl ock rate

too bi g

too smal l

I ncreased SHOoverhead

I ncreasedMS Tx power


RADIO RESOURCE UTILIZATION --- SHO optimization conclusion

> SHO overhead target level should be 30%~40%.• Addition window & Drop window optimization should be tuned first• Change the active set size if needed• Drop timer value is secondary• P-CPICH power could be the final parameter for SHO optimization(not

recommended!)• Optimization of active set weighting coefficient to give a stable SHO

performance


Coverage and Capacity issues

> Coverage-limited & Capacity-limited scenarios …

> Coverage & Capacity enhancement methods• Additional carriers and Scrambling codes• Mast Head Amplifiers• Remote RF Head Amplifiers• Repeaters• Higher-order Receiver Diversity• Transmit Diversity• Beam-forming• Sectorization


Coverage and Capacity issues---Coverage

Different service type([email protected], data@64,144,384kbps)supported with different link budget and thus different coverage range!

> How can coverage be deduced from link budget? link budget Max Path Losscell rangecoverage

> Generally, service coverage is uplink limited but system capacity may be limited by either uplink or downlink.

Hint: It’s critical to decide whether a specific area

should be planned for high data rate service coverage

or not

Hint: It’s critical to decide whether a specific area

should be planned for high data rate service coverage

or not

Service type Speech Data Data DataUplink bit rate(kbps) 12. 2 64 144 384Maximum transmit power(dBm) 21 21 21 21Antenna gain(dB) 0 0 2 2Body loss(dB) 3 0 0 0Transmit EIRP(dBm) 18 21 23 23Processing gain 25 17. 8 14. 3 10Required Eb/No(dB) 4 2 1. 5 1Target loading (%) 50 50 50 50Rise over thermal noise(dB) 3 3 3 3Thermal noise density(dBm/Hz) - 174 - 174 - 174 - 174Receiver noise figure(dB) 3 3 3 3Interference floor(dBm/Hz) - 168 - 168 - 168 - 168Receiver sensitivity(dBm) - 123. 1 - 117. 9 - 115 - 111. 1Rx antenna gain(dBi) 18. 5 18. 5 18. 5 18. 5Cable loss(dB) 2 2 2 2Fast fading margin(dB) 3 3 3 3Soft handover gain(dB) 2 2 2 2Isotropic power required (dBm) - 138. 6 - 133. 4 - 130 126. 6Allowed propagation loss(dB) 156. 6 - 154. 4 153. 4 149. 6


Coverage and Capacity issues---Capacity

> An uplink-limited scenario --- when the maximum uplink load is reached prior to the base station running out of transmit power.

> An downlink-limited scenario --- when the base station runs out of transmit power and additional users cannot be added without modifying the site configuration.

> Identifying the limited link:

Uplink limited Downlink limited

Limiting factor Uplink cell load BTS transmit power

Common reasons

Planned to a low uplink cell loadHigh BTS transmit power capabilityRelatively symmetric traffic

Planned to a high uplink cell loadLow BTS transmit powercapabilityGreater traffic on the downlink

IndicationsBTS transmit power not at maximumUplink cell load at maximum

BTS transmit power at maximumUplink cell load not at maximum

Solution Improve uplink load equationImprove downlink load equationImprove downlink link budget


Coverage and Capacity issues---Enhancement methods> Coverage & Capacity enhancement methods

• Additional carriers and Scrambling codes– System capacity is maximized by sharing the power across the available

carriers,e.g, two carriers configured with 10W can offer significantly greater capacity than a single carrier configured with 20W does.

– In downlink-limited capacity scenario,the number of supported users depends on the downlink channelisation code orthogonality. It is especially true when higher data rate service is supported in micro-cell.

• Mast Head Amplifiers– To reduce the composite noise figure of the bse station receiver subsystem.– But brings bad effects when in downlink-limited scenario.

• Remote RF Head Amplifiers– To allow the physical separation of base station’s RF and baseband

modules.– Maintaining the same service coverage performance while increasing cell

capacity.– Difference between remote RF head amplifiers and repeaters.


Coverage and Capacity issues---Enhancement methods(cont’d)> Coverage & Capacity enhancement methods(cont’d)

• Repeaters– Used for extending the coverage area of an existing cell, low-cost and ease

of installation but introduces delay.– Slight capacity loss in uplink-limited scenario.– Applicable in scenarios where clear cell dominance can be achieved such as

in rural areas or in tunnels.

Remote RF head amplifier Repeater

Application

Locating the entire logicalcell at a locatio normallyrequiring a long feeder run

Extending the coverageof an existing logical cell

Hardware atremote location

Tranmit power amplifiersand receiver front ends

Complete Rx and Tx chain forboth uplink and downlinkdirections

Connection to BS Optical link Usually a radio linkFunction Normal RF functions of the BS Non-intelligent retransmission


Coverage and Capacity issues---Enhancement methods(cont’d)

> Coverage & Capacity enhancement methods(cont’d)• Higher-order Receiver Diversity

– To overcome both the impact of fading across radio channel and increase the resulting signal-to-interference ratio.

– Improves uplink performance,especially beneficial for low-speed mobile terminals.

• Transmit Diversity– Downlink transmit diversity mandatory in 3GPP specifications,e.g. closed-

loop mode and open-loop mode.– Most effective when time- and multipath- diversity is inadequate,e.g. for

capacity gain in micro-cell scenario.

• Beam-forming– An effective technique for improving the downlink performance,especially

in environment with a low transmit element.– High mobile terminal complexity requirement and non-standard

functionality configuration.


Coverage and Capacity issues---Enhancement methods(cont’d)> Coverage & Capacity enhancement methods(cont’d)

• Sectorization– A general technique to increase cell capacity where antenna selection is

critical.– May require correspondingly high quantity of hardware with highly

sectorisation.– Usage

for typical Micro- cell deployme

nt

for typical Micro- cell deployme

nt

Sectorisation level Application

1 sector Microcell or low-capcity macrocell

2 sectorSectored microcell or macrocellproviding roadside coverage

3 sectorStandard macrocell configurationproviding medium capacity

4 or 5 sectorNot commonly used but may bechosen to support a specific traffic scenario

6 sector High-capacity macrocell configuration

for typical macro-cell deploymen

t

for typical macro-cell deploymen

t


CELL DEPLOYMENT

> Hierarchical Cell Structure(HCS) with two or more (FDD) carriers• Continuous macro-cells to provide full coverage as an “umbrella” layer.• Micro-cells to accommodate hot-spots with increased capacity and

higher bit rates in limited areas.• Typical air interface capacities are about 1Mbps/carrier/cell for a three-

sectored macro BS and 1.5Mbps/carrier/cell for a micro BS.

f 1 f1 f1

f1 f1 f1

f2

f1 f1 f1

f2

f2 f2 f2 f2 f2 f2

f1, f2 f1, f2 f1, f2 f1, f2 f1, f2 f1, f2

Conti nuous macro l ayerwi th f requency f1


Sel ected areas wi th mi crocel l s wi th f requency f2


Conti nuous mi cro l ayerwi th f requency f2

Both f requenci esconti nuousl y f1, f2used i n mi cro l ayer

No macro l ayer

> Example of WCDMA network evolution

An “umbrella” macro cell is best suited for high-

mobility users

An “umbrella” macro cell is best suited for high-

mobility users

Micro layer provides a very high capacity in a

limited area

Micro layer provides a very high capacity in a

limited area

Capacity enhancement

Capacity enhancement


CELL DEPLOYMENT

> Case study of frequency reuse in micro- and macro- networks

f 2

f2

f2

f1 f1, f2 f1, f2 f1

Continuous macro layer with frequency f2

Continuous micro layer with frequency f1 and f2

f 1, f2f1 f1 f1 f1

f1 f1 f1 f1

f1, f2 f1, f2 f1, f2 f1, f2

Reference scenario

Continuous macro layer with frequency f2

Continuous micro layer with frequency f1

Continuous macro layer with frequency f1 and f2

Continuous micro layer with frequency f1

Continuous macro layer with frequency f2Continuous micro layer with frequency f1

selected microcells reusing macro frequency f2

Reuse of micro frequency in macro layer

Reuse of macro frequency in micro layer

Reuse of macro frequency in selected micro cells

Reusing a micro carrier on all macro-cells does

not bring any improvements in network

performance!

Reusing a micro carrier on all macro-cells does

not bring any improvements in network

performance!

Reusing a macro carrier on all micro-cells can

support 10% more users than the reference scenario,but extra

Power Amplifier needed!

Reusing a macro carrier on all micro-cells can

support 10% more users than the reference scenario,but extra

Power Amplifier needed!

Micro-cells do not benefit from the other carrier reused from macro-cells if they still have unused

capacity on their own carrier!

Micro-cells do not benefit from the other carrier reused from macro-cells if they still have unused

capacity on their own carrier!

macro carrier reuse is not worth while when micro-cells

locates near macro-cells!

macro carrier reuse is not worth while when micro-cells

locates near macro-cells!


WCDMA Radio Network Planning

> overview

> Dimensioning

> Detailed planning

> Optimization aspects

> Adjacent carrier interference

> WCDMA & GSM Co-Planning


WCDMA Radio Network Planning---Network planning process overview

DefinitionDefinition Planning and ImplementationPlanning and Implementation O&MO&M

NetworkConfi gurati on

andDi mensi oni ng

Requi rementsand strategyfor coverage,qual i ty andcapaci ty per

servi ce

Coveragepl anni ngand si tesel ecti on

Propagati onmeasurements

coveragepredi cti on

Si teacqui si ti on

Coverageopti mi sati on

Capaci tyRequi rements

Traffi cdi stri buti on

al l owedbl ocki ng/

qeui ng Systemfeatures

ExternalInterference

Anal ysi s

Identi fi cati onAdaptati on

Parameterpl anni ng

Area/Cel lspeci fi csetti ng

HandoverStrategi es

Maxi muml oadi ng

Other RRM

NetworkOpti mi sati on

SurveyMeasurements

Stati sti calperformance

anal ysi s

Qual i tyEffi ci encyAvai l abl i ty


WCDMA Radio Network Planning ---Dimensioning(1)> What is Dimensioning?

--- to estimate the required site density and site configurations for the area of interest

• Radio Link Budget(RLB) and coverage analysis;• Capacity estimation • Estimation of the amount of base station hardware and

sites,radio network controllers,equipment at different interfaces and core network elements

• Knowledge of service distribution,traffic density, traffic growth estimates and QoS requirements are essential


WCDMA Radio Network Planning ---Dimensioning(2)

> Coverage analysis:• for the single-cell case*:

where

where is the received level at the cell edge, is the propagation constant, is the average signal strength threshold and is the standard deviation of the field strength and is the error function.

• for a typical macro-cellular environment – using Okumura-Hata model, the following formular gives an example for an

urban macro-cell with base station antenna height of 25m, mobile station antenna height of 1.5m and carrier frequency of 1950 MHz:

where is the maximum cell range and is the max path loss.

))1

(1()21

exp()(12

12 b

aberf

b

abaerfFu

))1

(1()21

exp()(12

12 b

aberf

b

abaerfFu 2

0

rPxa

20

rPxa

2

log10 10

enb

2

log10 10

enb

rPrP nn0x0x

erferf

)(log7.355.138 10 rLp )(log7.355.138 10 rLp rr pLpL

* “ Microwave Mobile Communications”, Jakes,W.C, John Wiley& Sons, 1974,126pp * “ Microwave Mobile Communications”, Jakes,W.C, John Wiley& Sons, 1974,126pp


WCDMA Radio Network Planning ---Dimensioning(3)> Capacity estimation

• WCDMA capacity and coverage are connected in terms of interference margin.

• Knowledge and vision of subscriber distribution and growth is a must.• Site configurations such as channel elements,sectors and carriers and site

density can be determined.• Capacity refinement may be obtained in late network optimization.

> RNC dimensioning• RNC dimensioning limited factors:

– Maximum number of cells(a cell is identified by a frequency and a scrambling code)

– Maximum number of Node B under one RNC– Maximum Iub throughput– Amount and type of interfaces(e.g. STM-1,E1)


WCDMA Radio Network Planning ---Dimensioning(4)> RNC dimensioning(cont’d)

• The number of RNCs needed to connect a certain number of cells

• The number of RNCs needed according to the number of BTSs to be connected

• the number of RNCs to support the Iub throughput

> Supported traffic (upper limit of RNC processing ability)

> Required traffic(lower limit of RNC processing ability)

> RNC transmission interface to Iub

2fillratebtsRNC

numBTSsnumRNCs

1fillratecellsRNC

numCellsnumRNCs

numSubsfillratetpRNC

PSdataTPCSdataTPvoiceTPnumRNCs

3


WCDMA Radio Network Planning ---Detailed Planning(1)

> Using Radio Network Planning(RNP) tools• To find an optimum trade-off between

quality,capacity and coverage criteria for all the services in an operator’s service portfolio.

• Integrated tools for dimensioning,network planning and optimization.

> Using Static simulator *• Static simulator flow

* “Static simulator for studying WCDMA radio network planning issues”,Wacker.A, Laiho-steffens.J,Sipila.K and Jasberg.M,VTC99’Spring pp2436-2440 * “Static simulator for studying WCDMA radio network planning issues”,Wacker.A, Laiho-steffens.J,Sipila.K and Jasberg.M,VTC99’Spring pp2436-2440

Gl obal i ni t i al i zat i on

I ni t i al i ze i terat i ons

Upl i nk i terat i on step

Downl i nk i terat i on step

Post processi ng

Graphi cal outputs

Coverage anal ysi s

I ni t i al i sati on phase

Combi ned UL/ DL i terati on

Post Processi ng phase


Creating a plan/load maps

Importing/creatingand editing sites and

cells

Link loss calculationPropagation model

tuning

Importingmeasurements

Importing/generating and

refining traffic layers

Defining servicerequirements

WCDMAcalculations

Analysis

Quality of Service

Neighbour cellgeneration

reporting

WCDMA Radio Network Planning ---Detailed Planning(2)> Example of RNP tool workflow

A plan usually includes parameter settings for the planned network elements such as:•Digital map& its properties•Target planning area propagation models•Antenna models•Selected radio access technology•BTS types and site/cell templates

A plan usually includes parameter settings for the planned network elements such as:•Digital map& its properties•Target planning area propagation models•Antenna models•Selected radio access technology•BTS types and site/cell templates

Site location,site ground height number of cells and antenna directionSite location,site ground height number of cells and antenna direction

Traffic planning:• Bearer service type and bit rate,• average packet call size and retransmission rate,• busy-hour traffic amount and traffic density for each service,• mobile list and WCDMA calculation

Traffic planning:• Bearer service type and bit rate,• average packet call size and retransmission rate,• busy-hour traffic amount and traffic density for each service,• mobile list and WCDMA calculation

Cite/BTS hardware template may include:•Maximum number of wideband signal processors•Maximum number of channel units •Noise figure•Available Tx/Rx diversity types

Cite/BTS hardware template may include:•Maximum number of wideband signal processors•Maximum number of channel units •Noise figure•Available Tx/Rx diversity types

A WCDMA cell template may include cell layer type,channel model,Tx/Rx diversity options,power settings, maximum acceptable load, propagation model,antenna infomation and cable losses

A WCDMA cell template may include cell layer type,channel model,Tx/Rx diversity options,power settings, maximum acceptable load, propagation model,antenna infomation and cable losses

To verify that the planned coverage, capacity and QoS criteria can be met with te current network deployment and parameter settings:• Run UL/DL iterations to calculate tx powers for MS and BS• Snapshot analysis for interference and coverage estimation• Optimizing dominance

To verify that the planned coverage, capacity and QoS criteria can be met with te current network deployment and parameter settings:• Run UL/DL iterations to calculate tx powers for MS and BS• Snapshot analysis for interference and coverage estimation• Optimizing dominance

Propagation models:•Macro cell---Okumura-Hata model•Micro cell---Walfisch-Ikegami model

Propagation models:•Macro cell---Okumura-Hata model•Micro cell---Walfisch-Ikegami model


WCDMA Radio Network Planning ---Detailed Planning(3)---UL/DL iteration steps

Set ol dThreshol ds to thedefaul t/ new coverage threshol ds

Cal cul ate new coveragethreshol ds

Check UL l oadi ng and possi bl y moveMSs tonew/other carri er or outage

Eval uate UL break cri teri on

Connect MSs to best server, cal cul ateneeded MS TxPower and SHO gai ns

Cal cul ate adj usted MS Txpowers, check MSs for outage

convergence

Cal cul ate new I =I _oth/ I _own

DL i terati on step

Post processi ng

END

i ni t i al i zati on

If n

o co

nver

genc

e

I ni t i al i ze del ta_C/ I _ol d

Al l ocate the CPI CH powers

Cal cul ate the recei ved Perch l evel s anddetermi ne the best server i n DL

Cal cul ate the MS sensi t i vi t i es

Determi ne the SHO connecti ons

Cal cul ate target C/ I ’ s

ful fi l l ed

UL i terati on step

Check CPI CH Ec/ I o cal cul ate theC/ I for each connecti on

cal cul ate C/ I for each MS

Post processi ng

END

Gl obal i ni t i al i zati on

Cal cul ate i ni t i al TX powers for al l l i nks

Check UL and DL breakcri teri a

Adj ust TX powers ofeach remai ni ng l i nk

accordi ng to del ta_C/ I

Update del ta_C/ I _ol d

I f not ful fi l l ed

UL iteration stepsUL iteration steps DL iteration stepsDL iteration steps


WCDMA Radio Network Planning ---Adjacent Channel Interference

> Adjacent Channel Interference(ACI) situation • Adjacent Channel Leakage Power Ratio(ACLR)

– the ratio of the transmitted power to the power measured in an adjacent channel

• Adjacent Channel Selectivity(ACS)– the ratio of the receive filter attenuation on the assigned channel frequency to the

receive filter attenuation on the adjacent channels

• Adjacent Channel Protection(ACP)– The ratio of adjacent channel power received by the base station as adjacent

channel interference power

NodeB@frequency1

0dB

BS ACP

Rx

0dB

MS ACLR

Tx

0dB

BS ACP

Rx

0dB

MS ACLR

Tx

f1

f1

f1f2

f2

f2

f1

wanted si gnal

f2

wanted si gnal

BS sel ecti vi ty

MS l eakage NodeB@frequency2

UL adjacent channel interference situationUL adjacent channel interference situation


WCDMA Radio Network Planning ---Adjacent Channel Interference

> Worst ACI cases---when a macro MS is coming too close to a micro BS

• Minimum Coupling Loss(MCL)– the smallest path loss between the transmitters and receivers– For a micro BS and MS, MCL is about 53dB– For a macro BS and MS, MCL is about 70dB

NodeB@frequency1

0dB

BS ACLR

Rx

0dB

MS ACP

Tx

0dB

BS ACLR

Rx

0dB

MS ACP

Tx

f1

f1

f1f2

f2

f2

f1

wanted si gnal

f2

wanted si gnal

BS l eakage

MS sel ecti vi ty NodeB@frequency2

DL adjacent channel interference situationDL adjacent channel interference situation


WCDMA Radio Network Planning ---Example of Worst ACI case> Worst ACI case when sites of different operators not co-

located

Dead Zonefor Operator 1

Operator 1 MSMax. TX power

si gnalsi gnal

ACIACI

Operator 1MS

Operator 2 Mi cro Cel lhi gh TX power

Operator 2 Mi cro Cel l

Operator 1 Macro Cel l

Assuming ACS and ACLR of values 33dB and 45dB respectively, the coupling C between the carriers can be calculated as:

Assuming ACS and ACLR of values 33dB and 45dB respectively, the coupling C between the carriers can be calculated as: dBC 7.32)1010(log10 10/4510/33

10

For uplink scenario, with a maximum MS power of 21dBm, 53dB for MCL to the micro BS and coupoing between the carriers of C=32.7dB,the received level at the micro BS and be estimated as if the background noise level is dBm, the micro BS would suffer a 38.4 dB noise rise form one macro user, which is located in the radio sense at the MCL distance form the micro BS, i.e. such a macro user would completely block the micro BS.

For uplink scenario, with a maximum MS power of 21dBm, 53dB for MCL to the micro BS and coupoing between the carriers of C=32.7dB,the received level at the micro BS and be estimated as if the background noise level is dBm, the micro BS would suffer a 38.4 dB noise rise form one macro user, which is located in the radio sense at the MCL distance form the micro BS, i.e. such a macro user would completely block the micro BS.

dBmdBdBdBm 7.647.325321

For downlink scenario, supposing the micro BS is transmitting with a minimum power of 0.5W(27dBm); then the received interference at the MS in the adjacent channel is

Assuming speech service (processing gain of Gp=25dB) with an Eb/No requirement at the Ms of 5dB and an allowed noise rise in the macro cell of 6 dB, the maximum allowed propagation loss Lp to keep the uplink connection working is

if we further consider a DL Tx Eb/No requirement of 8dB, the transmit power would need to be

For downlink scenario, supposing the micro BS is transmitting with a minimum power of 0.5W(27dBm); then the received interference at the MS in the adjacent channel is

Assuming speech service (processing gain of Gp=25dB) with an Eb/No requirement at the Ms of 5dB and an allowed noise rise in the macro cell of 6 dB, the maximum allowed propagation loss Lp to keep the uplink connection working is

if we further consider a DL Tx Eb/No requirement of 8dB, the transmit power would need to be

dBmACSdBMCLdBdBm 7.58)(7.32)(5327

dBdBdBmdBdBdBmLp 138)6103(25521

dBmdBdBdBdBmptx 3.621382587.58

This simple example shows that clearly in these cases the DL is the weaker link, i.e. before coming too close to a micro BS, the connection of a macro BS will be dropped due to insufficient DL power and it cannot block the micro BS.

This simple example shows that clearly in these cases the DL is the weaker link, i.e. before coming too close to a micro BS, the connection of a macro BS will be dropped due to insufficient DL power and it cannot block the micro BS.


WCDMA Radio Network Planning ---Optimization aspects(1)> Guidelines for Radio Network Planning to avoid ACI in multi-

operator environment• Base station and antenna locations

– Co-locate BSs– Deploy the antennas in a position as high as possible

• Base station configuration– Optimum antenna beam-width– “desensitisation”---increasing the noise figure

• Inter-frequency handovers• Inter-system handovers• Guard bands


WCDMA Radio Network Planning ---Optimization aspects(2)> Site locations and configurations

• Antenna installations(cable losses)• Optimum antenna tilting angle and correct antenna selection• Optimum sectorisation regarding to number of users and SHO

overhead.*

> Usage of mast head amplifier(MHA)**• Used in uplink direction to compensate for the cable losses• Improved uplink coverage probability• May have negative effect on downlink performance in case of downlink-

limited scenario

* “The impact of the base station sectorisation on WCDMA Radio Network Performance”,A.Wacker,J.Laiho-Steffens,K.Sipila,K.Heiska,VTC99’Amsterdam.** “The impact of the Radio Network Planning and Site Configuration on the WCDMA Network Capacity and Quality of Service”,J.Laiho-Steffens,A.Wacker, P.Aikio,VTC2000

* “The impact of the base station sectorisation on WCDMA Radio Network Performance”,A.Wacker,J.Laiho-Steffens,K.Sipila,K.Heiska,VTC99’Amsterdam.** “The impact of the Radio Network Planning and Site Configuration on the WCDMA Network Capacity and Quality of Service”,J.Laiho-Steffens,A.Wacker, P.Aikio,VTC2000


> Examples of maximum path losses with existing GSM and WCDMA system

WCDMA-GSM Co-Planning Issues

GSM900/speech

GSM1800/speech

WCDMA/speech

WCDMA/144kbps

WCDMA/384kbps

Mobile transmission power[dBm] 33 30 21 21 21

Receiver sensitivity[dBm]1

-110 -110 -124 -117 -113

Interference margin[dB]2

1 0 2 2 2

Fast fading margin[dB]3

2 2 2 2 2

Base station antenna gain[dBi]4

16 18 18 18 18

Body loss[dB]5

3 3 3

Mobile antenna gain[dBi]6

0 0 0 2 2Relative gain from lowerfrequency compared to UMTS

frequency[dB]7

11 1

Maximum path loss[dB] 164 154 156 154 150

1WCDMA sensitivity assuems 4.0dB base station noise figure and Eb/No of 5dB for 12.2kbps speech,1.5dB for 144kbps and 1.0dB for 384kbps

data.GSM sensitivity is assumed to be -110dBm with receive antenna diversity.

2 WCDMA interference margin corresponds to 37% loading of the pole capacity.An interference margin of 1.0dB is reserved for GSM900 because the

small amount of spectrum in 900MHz does not allow large reuse factors.

3The fast fading margin for WCDMA includes the macro diversity gain against fast fading.

4The atenna gain assumes three-sector configuration in both GSM and WCDMA.

5The body loss accounts for the loss when the terminal is close to the user's head.

6 A 2.0dBi antenna gain is assumed for the data terminal.

7The attenuation in 900MHz is assumed to be 11.0dB lower than in UMTS band and in GSM1800 band 1.0dB lower than in UMTS band.


WCDMA-GSM Co-Planning Issues---interference issues> Interference between the two system is the main issue

• Radio frequency issue– Second harmonics of GSM900 could probably fall into WCDMA uplink

band– Third-order inter-modulation products of PCS 1800 could be problematic

GSM 900935~960MHz

UTRATDD

UTRA FDD1920~1980

1900~1920MHz

f GSM=950~960MHz

f

Second-order harmonic distortion from GSM900

falling into WCDMA band

Second-order harmonic distortion from GSM900

falling into WCDMA band


WCDMA-GSM Co-Planning Issues ---interference issues

• Interference mechanisms from GSM system to WCDMA system– Adjacent Channel Interference(ACI):depends on Tx/Rx filter and spatial and

spectral distance between the own and adjacent carrier,the cell type and the power levels used.

– Wideband Noise(WB):from all out-of-band emission components.– Cross-modulation(XMD): depends on non-linearity of the MS receiver,the

duplex isolation and the transmitting mobile power.– Inter-Modulation Distortion(IMD):caused by non-linearities of RF

components of transmitter or receiver.

XMD is proportional to the square of transmitting

power and very sensitive to the Tx power of the MS!

XMD is proportional to the square of transmitting

power and very sensitive to the Tx power of the MS!

Typically in micro-cells

and could be reduced by

guard band.

Typically in micro-cells

and could be reduced by

guard band.

WCDMA BS GSM BS

ACI to WCDMA BS

ACI f romGSM BS

I MD at theWCDMA MS

Crossmodul ati on(XMD)

WB emi ssi onf rom GSM BS

Third-order IMD with mixture of products of

the GSM carrier frequencies f1 and f2:

2f1-f2 or 2f2-f1

Third-order IMD with mixture of products of

the GSM carrier frequencies f1 and f2:

2f1-f2 or 2f2-f1


GSM GSM GSM

WCDMA WCDMA WCDMA

GSM GSM

Urban area rural area

WCDMA-GSM Co-Planning Issues

Eval uate the qual i ty ofthe exi st i ng 2G network

Space avai l abl e for one-to-one reuse

Assure the coverage foral l WCDMA servi ces

Defi ne traffi cdi stri buti on rul es

between systems

Defi ne handover rul esbetween systems

Run combi ned 2G andWCDMA anal ysi s

Handover GSMWCDMA for capacity extension or service optimization

Handover GSMWCDMA for capacity extension or service optimization

Handover WCDMA-GSM for coverage extension

Handover WCDMA-GSM for coverage extension

Antenna sharing and co-located sites could be preferable.

Antenna sharing and co-located sites could be preferable.


Co-existing TDD & FDD modes ---UTRA TDD mode

> Some key parameters for the UTRA FDD and TDD modesRather low

spreading factors makes it inadequate

to reuse all the timeslots in all the

cells.That is,network must control which slots and directions are used in which

cells.

Rather low spreading factors

makes it inadequate to reuse all the

timeslots in all the cells.That is,network must control which slots and directions are used in which

cells.

UTRA FDD UTRA TDDFrame structure 15 slots/frame 15 slots/frameFrame length 10 ms 10 msChip rate 3.84 Mcps 3.84 McpsUplink spreading factors 4~512 1~16Number of parallel ULcodes per user 1 or 2Downlink spreading factors 4~512 1~ 16Number of parallel DLcodes per user 1~6 1~16Modulation QPSK QPSK

Power control update rate 1500Hz

theretically up to 800Hz;inpractice, only 100Hz in DLand 100Hz or possibly 200Hzin UL

Handover soft and hard hard onlyDynamic channel allocation N/A slow and fastIntra-cell interferencecancellation

support for advancedreceivers at base station support for joint detection

Not as fast as to follow fast fading

pattern!

Not as fast as to follow fast fading

pattern!


Co-existing TDD & FDD modes---Example of TDD RLB uplink/downlink

Example TDD link budget foruplink(RxD=receive diversity)

Voice12.2kbpsRxD

Voice12.2kbpsNo RxD

NRT data128kbpsRxD

NRT data128kbpsNo RxD

Transmitter(mobile)Max.Tx Power(dBm) 21 21 24 24MS antenna gain(dBi) 2 2 2 2Body loss(dB) 3 3 0 0EIRP(dBm) 20 20 26 26Receiver(base station)Number of used slots in TDD 1 1 1 1Thermal noise density(dBm/Hz) -174 -174 -174 -174Base station receiver noisefigure(dB) 5 5 5 5Desensitisation 0 0 0 0Receiver noise density(dBm/Hz) -169 -169 -169 -169Receiver noise power(dBm) -103.2 -103.2 -103.2 -103.2Interference margin(dB) 8 8 8 8Receiver interferencepower(dBm) -95.9 -95.9 -95.9 -95.9Total effective noise+interference(dBm) -95.2 -95.2 -95.2 -95.2Processing gain(dB) 12 12 2.4 2.4Required Eb/No(dB) 1.7 8.6 0.3 6.4Receiver sensitivity(dBm) -105.5 -98.6 -97.3 -91.2BS antenna gain(dBi) 4 4 4 4Cable loss in the basestation(dB) 0 0 0 0Fast fading margin(TPC headroom) (dB) 6.3 6.3 3.4 3.4Max.path loss(dB) 123.2 116.3 123.9 117.8

slotinchips

periodguardmidambleslotinchipsk

R

WGP __

___

15

Greater Eb/No difference between with or without RxD!

Greater Eb/No difference between with or without RxD!

Smaller Max path loss than that of FDD scenario TDD cells

have smaller radius!

Smaller Max path loss than that of FDD scenario TDD cells

have smaller radius!

Example TDD link budget fordownlink(No TxD)

Voice12.2kbps

NRT data128kbps

Transmitter(mobile)

Max.Tx Power(dBm) 24 24

BS antenna gain(dBi) 4 4

Cable loss in BS(dB) 0 0

EIRP(dBm) 28 28

Receiver(mobile)

Number of used slots in TDD 1 1

Thermal noise density(dBm/Hz) -174 -174Mobile station receiver noisefigure(dB) 9 9

Receiver noise density(dBm/Hz) -165 -165

Receiver noise power(dBm) -99.1 -99.1

Interference margin(dB) 8 8Receiver interferencepower(dBm) -91.9 -91.9Total effective noise+interference(dBm) -91.1 -91.1

Processing gain(dB) 12 2.4

Required Eb/No(dB) 9.4 6.7

Receiver sensitivity(dBm) -93.7 -86.8

Mobile antenna gain(dBi) 2 2

Body loss(dB) 3 0Fast fading margin(TPC headroom) (dB) 5.5 3.1

Max.path loss(dB) 115.2 113.7


Co-existing TDD & FDD modes--- TDD/TDD interference> Interference scenarios

> TDD-TDD Interference scenarios/solutions• MS to MS interference---when MS1 is transmitting while MS2 is

receiving, especially at cell borders.– Cannot be avoided by network planning,but may benefit from

– DCA and radio resource management– Power control

• BS to BS interference---when BS1 is transmitting while BS2 is receiving

– depends heavily on BS locations.– Could be avoided by providing sufficient coupling loss

between base stations– BSs better be synchronized and of same asymmetry.


Co-existing TDD & FDD modes --- TDD/FDD interference> TDD-FDD Interference scenarios/solutions

• TDD MS to FDD BS– To make FDD/BS less sensitive,especially for small pico cells– To place BS antenna as high as possible from TDD MSs

• FDD MS to TDD BS– Inter-frequency or inter-system may be helpful

• FDD MS to TDD MS– Use downlink power control of TDD BS to compensate for the interference

from FDD MS – Inter-system/inter-frequency handover

UTRA TDDTx/ Rx

UTRA FDD/ UL Sate-l l i te

UTRATDD

Tx/Rx

1900 1920 1980 2010 2025 (MHz)

Interference mainly between TDD and FDD/UL

frequency bands!

Interference mainly between TDD and FDD/UL

frequency bands!


Co-existing TDD & FDD modes

> UTRA TDD• Advantage in the unpaired spectrum operation• Better utilized for asymmetric service at high data rate• Can build stand-alone wide-area TDD network(?) or serve as a separate

capacity-enhancing layer in the network• Lower Max. Path loss compared with FDD scenario• Lower “cell breathing” and thus more stable service coverage• Requires strict synchronization especially in uplink• Low-rate services often goes to code-limited cases while high-rate

services goes to interference-limited cases

From the service point of view, UTRA TDD is most suited for small cells and high data rate services!

From the service point of view, UTRA TDD is most suited for small cells and high data rate services!

Thanks!

Wcdma Radio Network Planning And Optimization

Technology

Transcript of Wcdma Radio Network Planning And Optimization