Stealth Cognitive Radio With MIMO Active Interference Cancellation and V-BLAST Date: 2007.10.19...

Stealth Cognitive Radio With MIMO Active Interference

Cancellation and V-BLAST

Date: 2007.10.19Speaker: 王貞傑指導教授 : 吳仁銘

Outline

• AIC• Algorithm• simulation

• V-blast• Algorithm• simulation

• MIMO-AIC

Active Interference Cancellation (AIC) Algorithm

Active Interference Cancellation (AIC) Algorithm

127

0

))(128

2exp(),(n r

lk

njklP )]1128(,0[ rl

127

0

127

0

127

0

),()(128

1

)))(128

2exp()((128

1)(

k

n k

klPkX

r

lk

njkXlY

)]1128(,0[ rl

]127,0[k

gPd 1

11 dhP

TXXXXg )]127()89(00000)83()0([ TrXrXrXrXrXd )]186()86()185()85()184([1

)88:84,186:184(1 rrPPT

XXXXXh

)88()87()86()85()84(

^^^^^

1111

1

11 dWdPPPh TT

gWPgWh 21

2

112 dhPe Minimization

Active Interference Cancellation (AIC) Simulation

0 25 50 75 100 125-300

-250

-200

-150

-100

-50

0

50

Po

we

r sp

ect

rum

subcarrier

3-tone AIC 5-tone AIC 7-tone AIC 9-tone AIC

3-tone AIC

5-tone AIC

7-tone AIC

9-tone AIC

Power Spectrum after AIC

Active Interference Cancellation (AIC) Simulation

0 25 50 75 100 125 150-300

-250

-200

-150

-100

-50

0

50Comparison of Power spectrum with AIC and Turn-off

subcarrier

pow

er m

agni

tude

(dB

)

9-tone AIC

9-tone turn-off

Outline



• MIMO-AIC

Vertical Bell Laboratories Layered Space-Time (V-BLAST) Encoding

Vertical Bell Laboratories Layered Space-Time (V-BLAST) Decoding


vaHr 1

ij

ijHw ijk

Tk ji

1

0

22

2

:symbol detectedfor SNRdetection -post

i

i

i

k

k

kw

a

},,2,1{ Mk i

ers transmittM, receivers N

MNH


• Initialization: Recursion: 1i

HG1

2

11 )(minarg jj

Gk

ii kik Gw )(

i

H

kk rwyii

)(ˆii kk yQa

ii kkii Harr )(ˆ1

iki HG 1

2

11 )(minarg1

jikkj

i Gki

1 ii

HH HHHHG 1)(

HH HIHHG 12 )(

V-Blast Simulation

0 5 10 15 20 25 3010

-4

10-3

10-2

10-1

100

SNR(dB)

BE

R1

V-BLAST(2x2)

Outline



• MIMO-AIC

MIMO-AIC• Assumptions: The channel is random, flat-fading or quasi-static, frequency independent

(but changing from frame to frame is accepted or that is to say this rule constrains inside a frame).

The channel gains, signals and noise are independent.

Perfect channel state information (CSI) should be assumed to be available at the receiver end.

We have assumed perfect timing and synchronization so that there’s no more degradation.

The noise vector is complex AWGN.

we have already known first transmitter data sequence so as to operate the AIC action at second receiver to clean interference from both transmitters.

MIMO-AIC

• Assumptions:• QPSK• Oversampling rate=4

Final oversampling rate (comparison)=20• 2x2 UWB channel ( CM1~CM4)• Tx1 :data• Tx2 :AIC (around preserved band)

data (left subcarriers)

),,,( 22211211 HHHHH

MIMO-AIC

Tx2_DATATx2_DATA

Tx1_DATATx1_DATA Tx1_Victim

Tx2_AIC

Tx1_Victim

Tx2_AIC

(2)

(1)

Tx 1 Rx 1

Tx 2 Rx 2

Tx Rx (V-BLAST)

H11

H22

H21

H12

2 x 2 MIMO AIC Architecture

Tx2_DATATx2_DATA


Tx2_AIC

Frequency allocation

MIMO-AIC(1)

Tx 1 Rx 1

Tx 2 Rx 2

Tx Rx (V-BLAST)

H11

H22

H21

H12


Tx2_DATATx2_DATA


Tx2_AIC


0 25 50 75 100 125-120

-100

-80

-60

-40

-20

0

20

40

Po

we

r sp

ect

rum

(d

B)

subcarrier

SNR=0 dB SNR=5 dB SNR=10dB SNR=15dB SNR=20dB SNR=25dB SNR=30dB

H=(CM1,CM1,CM1,CM1)

0 25 50 75 100 125-120

-100

-80

-60

-40

-20

0

20

40

po

we

r se

ctru

m(d

B)

subcarrier


H=(CM1,CM1,CM2,CM2)

0 25 50 75 100 125-120

-100

-80

-60

-40

-20

0

20

40

Pow

er s

pec

trum

(d

B)

subcarrier


H=(CM1,CM1,CM3,CM3)

0 25 50 75 100 125

-120

-100

-80

-60

-40

-20

0

20

40

Pow

er s

pect

rum

(dB

)

subcarrier


H=(CM1,CM1,CM4,CM4)

MIMO-AIC(1)

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 321E-4

1E-3

0.01

0.1

1

BE

R

SNR(dB)

Tx1_Victim (1111) Tx1_DATA (1111) Tx2_AIC (1111) Tx2_DATA (1111) Tx1_Victim (1122) Tx1_DATA (1122) Tx2_AIC (1122) Tx2_DATA (1122) Tx1_Victim (1133) Tx1_DATA (1133) Tx2_AIC (1133) Tx2_DATA (1133) Tx1_Victim (1144) Tx1_DATA (1144) Tx2_AIC (1144) Tx2_DATA (1144)

Tx2_AIC

Tx1_Victim

Tx1_DATATx2_DATA

MIMO-AIC(2)

Tx 1 Rx 1

Tx 2 Rx 2

Tx Rx (V-BLAST)

H11

H22

H21

H12


Protect band


Tx1_Victim

Tx2_AIC

0 25 50 75 100 125

-300

-250

-200

-150

-100

-50

0

Pow

er s

pect

rum

(dB

)

subcarrier


H=(CM1,CM1,CM1,CM1)

0 25 50 75 100 125

-300

-250

-200

-150

-100

-50

0

Po

we

r sp

ect

rum

(d

B)

subcarrier


H=(CM1,CM1,CM2,CM2)

0 25 50 75 100 125

-350

-300

-250

-200

-150

-100

-50

0

Po

we

r sp

ect

rum

(d

B)

subcarrier


H=(CM1,CM1,CM3,CM3)

0 25 50 75 100 125

-350

-300

-250

-200

-150

-100

-50

0

Po

we

r sp

ect

rum

(d

B)

subcarrier


H=(CM1,CM1,CM4,CM4)

MIMO-AIC(2)

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 321E-4

1E-3

0.01

0.1

BE

R

SNR (dB)

Tx1(1111) Tx1(1122) Tx1(1133) Tx1(1144)

More analysis for Victim part and AIC part

Tx 1 Rx 1

Tx 2 Rx 2

Tx Rx (V-BLAST)

H11

H22

H21

H12


Tx2_DATATx2_DATA

Tx2_Protect

Tx1_DATA Tx1_DATA

Tx1_Protect

Protect band

Frequency allocationTx1_Vitctim

Tx2_AIC

More analysis for Victim part and AIC part

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32

1E-4

1E-3

0.01

0.1

BE

R

SNR (dB)

Tx1_Victim (1111) Tx1_DATA (1111) Tx1_Protect(1111) Tx2_DATA (1111) Tx1_Victim (1122) Tx1_DATA (1122) Tx1_Protect(1122) Tx2_DATA (1122) Tx1_Victim (1133) Tx1_DATA (1133) Tx1_Protect(1133) Tx2_DATA (1133) Tx1_Victim (1144) Tx1_DATA (1144) Tx1_Protect(1144) Tx2_DATA (1144)

Tx1_Victim

Tx1_DATATx1_ProtectTx2_DATA

Reference

• H. Yamaguchi, “Active Interference Cancellation Technique for MB-OFDM Cognitive Radio,” Microwave Conference, 2004. 34th European Volume 2, pp.1105-1108, 13 Oct. 2004.

• P. W. Wolniasky, G. J. Foschini, G.D. Golden, and R. A. Valenzuela. “V-blast: An architecture for realizing very high data-rates over the rich-scattering wireless channel,” Proc. IEEE ICC-00, New Orleans, LA, USA, 18-22 June 2000.

• http://mimo.cm.nctu.edu.tw/Courses/Special_Topics_on_DSP_2007.htm, Ta-Sung Lee, Signal Processing for Wireless Communications, spring semester in 2007.

http://mimo.cm.nctu.edu.tw/Courses/Special_Topics_on_DSP_2007.htm

http://mimo.cm.nctu.edu.tw/Courses/Special_Topics_on_DSP_2007.htm

Stealth Cognitive Radio With MIMO Active Interference Cancellation and V-BLAST Date: 2007.10.19...

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