CDMACDMAmobile mobile

communicationcommunication

Raf AppeltansRaf Appeltans

Niels ThijsenNiels Thijsen

Overzicht Overzicht

MA-TechniekenMA-Technieken ReviewReview DS-CDMADS-CDMA MC-CDMAMC-CDMA SpectraSpectra

SimulatiesSimulaties ConclusiesConclusies Q & AQ & A

Review Review

Multiple AccesMultiple Acces TDMATDMA FDMA FDMA CDMACDMA

DS-CDMADS-CDMA MC-CDMAMC-CDMA

DS-CDMADS-CDMADS-CDMA

Transmitter

DS-CDMADS-CDMADS-CDMA Receiver – AWGN

Channel

MC-CDMAMC-CDMAMC-CDMA Transmitter

MC-CDMAMC-CDMA

equaliser despreaderH*

-------|H|²

MC-CDMA Receiver

SpectraSpectra

Overzicht Overzicht

MA-TechniekenMA-Technieken SimulatiesSimulaties

AWGNAWGN MultipathMultipath

ConclusiesConclusies Q & AQ & A

SimulatiesSimulaties

DS-CDMAMC-CDMA

1,00E-06

1,00E-05

1,00E-04

1,00E-03

1,00E-02

1,00E-01

1,00E+00

-10 -8 -6 -4 -2 0 2 4 6 8 10

Eb/No (dB)

BE

R

DS-CDMA 64 users

DS-CDMA 8 users

DS-CDMA 1 user

MC-CDMA 64 users

MC-CDMA 8 users

MC-CDMA 1 user

AWGN ChannelAWGN Channel

Multipath ChannelMultipath Channel

SimulatiesSimulaties

BER DS-CDMA AWGN + Multipath

0,000001

0,00001

0,0001

0,001

0,01

0,1

1

-4 -2 0 2 4 6 8 10 12 14 16

Eb/N0

BE

R

DSBER1

DSMPBER1

DS-CDMA – AWGN + MultipathDS-CDMA – AWGN + Multipath

Rake ReceiverRake Receiver

SimulatiesSimulaties

BER DS-CDMA AWGN + Multipath + Rake receiver

0,00000001

0,0000001

0,000001

0,00001

0,0001

0,001

0,01

0,1

1

-4 -2 0 2 4 6 8 10 12 14 16

Eb/N0

BE

R

DSBER1

DSMPBER1

DSMPRAKEBER1

DS-CDMA – AWGN + Multipath - Rake receiverDS-CDMA – AWGN + Multipath - Rake receiver

SimulatiesSimulaties

BER DS-CDMA AWGN + Multipath & Rake receiver

0,00000001

0,0000001

0,000001

0,00001

0,0001

0,001

0,01

0,1

1

-4 -2 0 2 4 6 8 10 12 14 16

Eb/N0

BE

R

DSBER1

DSMPBER1

DSMPRAKEBER1

DSMPRAKEBER8

DSMPRAKE16

DS-CDMA – AWGN + Multipath-channel - Rake DS-CDMA – AWGN + Multipath-channel - Rake receiverreceiver

Multiple usersMultiple users

MC-CDMAMC-CDMA

SimulatiesSimulatiesMC-CDMA - AWGN + Multipath Channel MC-CDMA - AWGN + Multipath Channel

BER MC-CDMA - AGWN + Multipath Channel

1,00E-06

1,00E-05

1,00E-04

1,00E-03

1,00E-02

1,00E-01

1,00E+00

-4 -2 0 2 4 6 8 10 12 14 16

Eb/N0

BE

R

MCBER1

MCMPBER1

MCMPBER8

MCMPBER16

DSMPBER1

ConclusionsConclusions Rake receiver te statischRake receiver te statisch Equalising bij MC niet goed genoegEqualising bij MC niet goed genoeg Bij meerdere users steeds slechterBij meerdere users steeds slechter

CDMA links hebben nood aan coderingCDMA links hebben nood aan codering(i.e. convolution codes )(i.e. convolution codes )

Multi-user detectionMulti-user detection

Q & AQ & A