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CDMA System BasisCDMA System Basis

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Features of Wireless TelecommFeatures of Wireless Telecomm

a IndividuallyIndividuallya Bad propagation environmentBad propagation environmenta Co-channel, Adjacent channel interferenceCo-channel, Adjacent channel interference

and near-far effect.and near-far effect.a Contradiction between limited frequencyContradiction between limited frequency

resource and vast numbers of subscribers.resource and vast numbers of subscribers.a Complicated network and controlComplicated network and control

equipment are required.equipment are required.

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Classification of WirelessClassification of WirelessTelecommTelecomm

ClassificationMode

Class

RF Operation Simplex, half-duplex, duplex

Signal Analog, Digital

Modulation FM, PM, AM

MultipleAccess

FDMA, TDMA, CDMA

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Frequency Reuse

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Makeup of Wireless TelecommMakeup of Wireless Telecomm

MS

MS

MSBTS BTS

BTSBSC

MSC

BTSBTS

BTS

BSC

UmAbis A

BSS

PSTN

HLR

VLR

MSC

ISDN

MS

MS: Mobile StationBSS: Base StationSystem

BTS: Base-stationTransceiver SystemBSC: Base_StationControllerMSC:Mobile-serviceSwitching CenterVLR:Visiting LocationRegisterHLR:Home LocationRegisterPSTN:ISDN:

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Spectrum Spreading TechniqueSpectrum Spreading Technique

a Theoretical Basis isTheoretical Basis is Shanon equationShanon equationC=B*logC=B*log22(1+S/N)(1+S/N)

a DSSS applied in CDSSS applied in CDMA DMA a Used in military communication in 1950sUsed in military communication in 1950s

and 1960sand 1960sa Qualcomm company successfully put it intoQualcomm company successfully put it into

commercially cellular wirelesscommercially cellular wirelesstelecommunication by the end of 1980stelecommunication by the end of 1980s

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Signal processing by DSSSSignal processing by DSSS

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Features of CDMA SystemFeatures of CDMA System 11

a Large capacityLarge capacity8~10 times of analog system8~10 times of analog system

a High-quality serviceHigh-quality service88Kb/s QCELP EQUALS 13Kb/s of GSM;Kb/s QCELP EQUALS 13Kb/s of GSM;13Kb/s QCELP EQUALS 64kb/s of wireline13Kb/s QCELP EQUALS 64kb/s of wireline

a Soft handoff lowers call drop rateSoft handoff lowers call drop ratea RAKE receiving overcomes multi-path fadingRAKE receiving overcomes multi-path fadinga Good secrecyGood secrecy

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Features of CDMA SystemFeatures of CDMA System 22

a Soft capacitySoft capacitya MSs averaging transmission power isMSs averaging transmission power is

lowered, decreasing radiation to humanlowered, decreasing radiation to humanbody and environment . Be named as Greenbody and environment . Be named as GreenHandsetHandset

a Easy to realize dual-mode operationEasy to realize dual-mode operationa System complexity increasedSystem complexity increased

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Key techniques of CDMA Key techniques of CDMA 11

a Diversity receivingDiversity receivingTime diversityinterleaving, error-detectionTime diversityinterleaving, error-detection

and correctionand correctionFrequency diversityinherent feature ofFrequency diversityinherent feature of wideband communication wideband communicationSpace diversitymultiple antenna receiving,Space diversitymultiple antenna receiving,

RAKE receiving, soft handoffRAKE receiving, soft handoff

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Key techniques of CDMA Key techniques of CDMA 22

a Precise power controlPrecise power controlOpen loop power control on reverse link Open loop power control on reverse link Closed loop power control on reverse link Closed loop power control on reverse link

Outer loop power control on reverse link Outer loop power control on reverse link

Power control on forward link Power control on forward link

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Key techniques of CDMA Key techniques of CDMA 33

a Rate variable codec (Rate variable codec ( QCELP)QCELP)a VOICE Detection (VOD) VOICE Detection (VOD)a SynchronizationSynchronizationa Mobile assisted soft handoffMobile assisted soft handoff

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Key techniques of CDMA Key techniques of CDMA 44

a Blossoming & WiltingBlossoming & Wiltinga LowLowEEbb /N/Noo and high redundant errorand high redundant error

correction encodingcorrection encodinga Multiple accessMultiple access long PN code, short PNlong PN code, short PN

code and WALSH orthogonal codecode and WALSH orthogonal code

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Forward Traffic

Traffic ChannelForward

Channel

Paging

Forward TrafficChannel

CDMA Cell Site

Sync

Pilot

Walsh CodeAssignment

0-> Pilot32 ->Sync

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IS-95A Channel Modulation--Forward Link IS-95A Channel Modulation--Forward Link

ConvolutionalEncoder

r = 1/2, K = 9

PagingChannel

Bits

CodeSymbol

Symbol

Repetition

ModulationSymbol

WalshFunction p

DecimatorLong CodeGenerator

Long CodeMask for

PagingChannel p

9.6 kbps4.8 kbps2.4 kbps1.2 kbps

ConvolutionalEncoder

r = 1/2, K = 9

Forward TrafficChannel code

channelInformation

Bits for User mwith Rate Set 1(172, 80, 40, or16 bits/frame)

CodeSymbol

BlockInterleaver

Add 8-bitEncoder Tail

per Frame

Add FrameQuality Indica-tors (12, 8, 0, or

0 bits/frame)8.6 kbps4.0 kbps2.0 kbps0.8 kbps

SymbolRepetition

ModulationSymbol

ModulationSymbol

19.2 ksps

PowerControl

Bits

800 bps

MUX*

800 Hz

9.6 kbps4.8 kbps

SyncChannel

Bits

PilotChannel(All 0s)

WalshFunction 0

19.2 ksps

Block

Interleaver

ModulationSymbol

19.2 ksps9.6 ksps4.8 ksps2.4 ksps

19.2 ksps19.2 ksps9.6 ksps

19.2 ksps

ConvolutionalEncoder

r = 1/2, K = 9

CodeSymbol

SymbolRepetition

ModulationSymbol

WalshFunction 32

1.2 kbpsBlock

Interleaver

ModulationSymbol

4.8 ksps2.4 ksps 4.8 ksps

19.2 ksps

1.2288 Mcps

DecimatorLong CodeGenerator

Long CodeMask forUser m

19.2 ksps

1.2288 McpsDecimator

WalshFunction n

A

A

A

A

* Power control bits are not multiplexed in for suppemental code cha nnels of the Forward Traffic Channels

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Procedure of MSs COMMUNICATIONProcedure of MSs COMMUNICATION

a Searching base stations pilot channelSearching base stations pilot channela Demodulating synchronizing channelDemodulating synchronizing channela MS requests on access channelMS requests on access channela BS responds on paging channelBS responds on paging channela

Traffic channel is assigned forTraffic channel is assigned forcommunicationcommunication

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Power On

MSInitialStatus

MS idle

status

Systemaccessstatus

MS in trafficChannel

status

MS fully catchesSystem timing

MS paged, originatingor registering

MS idle changeover when

NGHBR_CONFIGis011

Access channelconfirmation

End traffic channel

Indication of trafficchannel

Task Initialization Start analog mode

End analog mode

Notes not all are listed out

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ZXC10-BSS System structure-BSC

BSC: Base_Station ControllerBTS: Base-station Transceiver

SystemNCM: Network Control ModuleHIRS: High-speed Interconnect

Router SubsystemCDSU: Channel/Digital Service UnitTCM: Timing Control ModuleSVM: Selector Vocoder ModuleSVICM: Selector Vocoder Interface

Control ModuleCPM: Call Process Module

OMC: Operation & MaintenanceCenterS V M

S V MS V M

..

.

B T SB T SB T S

L A N

T O O M C

SVIC

H I R S

C D S U

A b i s A b i s

G psor Glonas

M S C

C P M

B S C

S V M

S V MS V M

..

.

N C M

T C M

SVIC

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ZXC10-BSS System structure-BTS

B S C

Gps or Glonass

TCM RFIM

TRx HPA RFE

BTMCCM

CDSU

O t h e r B T S

HIRS

CHM

CHMCH M

. ..

A T M o r E 1

B T S

BTS: Base-station Transceiver SystemCHM: Channel Processing ModuleCCM: Communication Control ModuleHIRS: High-speed Interconnect Router

SubsystemTCM: Timing Control ModuleRFIM: RF Interface ModuleTRx: TransceiverHPA: High Power AmplifierRFE: RF Front EndCDSU: Channel/Digital Service UnitBTM: Base-station Test Module

BSC: Base-station Controller

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ZXC10_BSS SystemSpecification-BSC

a Maximal BTS supported: 512a Vocoder 7200a Maximal Channels (including payoff and soft handoff):512 X 32 = 16384

a Maximal traffic channels: 512 X 20 = 10240a Maximal subscribers: 102,500*a BTS side traffic 2,930 Erl*a BHCA 125,000*a Traffic 1.28BHCA/subscriber

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ZXC-10 BSS-transition to 3G

CapacityincreasedNon-symmetricaldata serviceprovided

q For:64Kb/sq Rev:14.4Kb/s

Backward

compatible with95A

I S 9 5 A I S 9 5 B C D M A 2 0 0 0 1 XC D M A 2 0 0

Capacity doubled(relative to 95A)Data service

q 144Kb/sq 307.2Kb/s(max)

Backwardcompatible with95A/B

Data serviceq 384Kb/sq 2Mb/s(max)

Backwardcompatible with95A/B/1X

Features: