Nagoya Institute of Technology

Transcription

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3 OFDM SC-FDE (single carrier-fde)ofdm PAPR 3

4 OFDM SC-FDE (single carrier-fde)ofdm PAPR 4

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6 Mobility 2G GSM PDC PHS 3G WCDMA cdma2000 WLAN IEEE802.11b 4G WLAN IEEE802.11g, n BWA 10kbps 2Mbps 10Mbps 100Mbps 1Gbps 6

7 C B log 2(1 S Hz / N ) bit/sec AWGN 7

8 OFDM SC-FDE (single carrier-fde)ofdm PAPR 8

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11 data s / p QPSK mapping I Q LPF LPF /2 cos BPF PA s(t) chan nel AWGN n(t) r(t) LNA transmitter channel receiver BPF /2 I Q cos LPF LPF QPSK demapping p / s data data RF s / p QPSK mapping LPF s(t) chan nel AWGN n(t) r(t) LPF transmitter channel receiver QPSK demapping p / s data 11

12 h(, t) t s(t) h(,t) n(t) r(t) rt () h(,) t st () nt () H(f, t) 12

13 h(, t) h(, 0) received power (db) s(t) h(,t) n(t) r(t) delay time (s) h(, 1) received power (db) delay time (s) 13

14 OFDM SC-FDE (single carrier-fde)ofdm PAPR 14

15 h(,) t c() t () t Jakes received power (db) c(t)(t) delay time (s) n v m/s (vcosn)/ Hz m 15

16 cos(2f 0 t)+cos(2{f 0 +f}t) f 0 =1, f= E+01 c(t) amplitude 1.E+00 1.E-01 1.E t sec 16

17 or s(t) c(t) n(t) r(t) rt () ctst () () nt () 17

18 c(t) NLOS (non-line-of-sight) 2 r r f( r) exp r c(t) LOS (line-of-sight) 2 2 ( ) r exp r a ar f r I a I 0 18

19 1.E+01 1.E+00 fd Hzv m/s f0 Hzc f d vf c f d fdts=0.001 fdts=0.005 fdts=0.01 amplitude 1.E-01 1.E-02 1.E time sec fdts=0.001 fdts=0.005 fdts=0.01 phase / pi Ts=0.001 sec Ts time sec 19

20 r(t) rt () ctst ()() nt () data serial to parallel QPSK mapping pilot symbol insertion s(k) LPF Rayleigh fading c(k) data parallel to serial decision ^r(k) channel equalization r(k) LPF AWGN n 0 (k) without consideration at this time channel estimation 20

21 c(t) ZF rk ( ) nk ( ) rk ( ) sk ( ) ck ( ) ck ( ) MMSE * c k ( ) rk ( ) rk ( ) ck ( ) E sk ( ) rk ( ) cksk ( ) ( ) nk ( ) sk ( ) rk ( ) nk ( ) 2 rk ˆ( ) ck ( ) k c(t)c(f)lpf 21

22 1.E+00 1.E-01 1.E-02 Ts=0.001, QPSK ZF fdts BER 1.E-03 1.E-04 1.E-05 1.E-06 fdts=0.001 w/ eq. fdts=0.001 w/o eq. fdts=0.01 w/ eq. fdts=0.01 w/o eq. theory Avg. Eb/N0 db 22

23 OFDM SC-FDE (single carrier-fde)ofdm PAPR 23

24 h(t,) [db] H( f, t) H( f) h 6 h 7 h8 h 9 0 h 0 h 1 T s h 2 h 3 h4 h 5 2T s 1 db 9T s 24

25 Ts received power (db) delay time (s) received power (db) trans. rate = 250 Kbps Ts= 4 s delay time (s) delay time (s) 0 4 received power (db) trans. rate = 3.84 Mbps Ts= 0.26 s 25

26 H(f) h(t,) [db] h(t,) [db] h(t,) [db] h 0 1 db h () h 1 h 2 h 3 h4 h 5 h 6 h 7 h8 h T s 2T s 0 2T s 9T s T s 1.E+00 1.E+01 1.E+01 Hf () amplitude 1.E-01 amplitude 1.E+00 1.E-01 amplitude 1.E+00 1.E-01 1.E-02 1.E-02 1.E-02 H (L=1) H (L=10, 10dB decayed) H (L=10, 1dB decayed) 1.E-03 1.E-03 1.E f Hz f Hz f Hz 26

27 H(f) L1 rk ( ) hsk ( l) nk ( ) l l 0 L1 rk ( ) hs l ( k l) nk ( ) rk ˆ( ) sk ( ) h h h 0 l1 0 0 h l = 27

28 FDE: frequency domain equalization r( k) h0s( k) h1 s( k 1) hl 1s( k L 1) n( k) ZF MMSE R( n) h h e h e S ( n) N ( n) 2 nt s N 2 n ( L 1) T s N 0 1 L 1 H ( n) S ( n) N ( n) Rn ( ) Nn ( ) Rn ( ) Sn ( ) Hn ( ) Hn ( ) Rn ( ) Rn ( ) H * ( n) Hn ( ) ESn ( )

29 OFDM SC-FDE (single carrier-fde)ofdm PAPR 29

30 data (orthogonal frequency division multiplexing) serial to parallel QPSK mapping S / P S(n) R(n) ^ IFFT R(n) guard interval insertion pilot symbol insertion s(k) channel h(k) data parallel to serial decision P / S FDE FFT guard interval removal r(k) AWGN n(k) LANWiMAX channel estimation 30

31 I-channel t sec Ts=0.001 sec, K=64 QPSK 1.E+01 amplitude 1.E+00 1.E-01 1.E-02 1.E-03 1.E-04 1.E f Hz 31

32 peak to average power ratio 32

33 1 OFDM 1 K 0 Ts sec 0 Ts sec 1 1 T=KTs sec Ts TsT 33

34 ISI: inter-symbol interference OFDM1 K OFDM GI: guard interval OFDM1 K 34

35 h 2 h 3 h 4 h(t,) [db] h 0 h 1 h 5 h 6 h 7 h 8 h 9 i.i.d independently and identically distributed 0 2T s T s 35

36 BER 1.E+00 1.E-01 1.E-02 1.E-03 L=1 L=2 L=4 L=8 L=10 L=16 theory Ts=0.001 sec, K=64 T=0.064 sec QPSKOFDM GI=T/8=8Ts LTs ZF 1.E-04 1.E Avg. Eb/N0 db 36

37 h 2 h 3 h4 h(t,) [db] h 0 h 1 h 5 h 6 h 7 h8 h L1 Rn ( ) h( n) Sn ( ) h( n) Sne ( ) 0 1 h nsne Nn 2nT j2 n( L1) Ts/ N L1( ) ( ) ( ) 0 2T s r( k) h ( k) s( k) h( k1) s( k1) h ( kl1) s( kl1) n( k) T s s N p28

38 OFDM SC-FDE (single carrier-fde)ofdm PAPR 38

39 single carrier- cyclic prefix data serial to parallel QPSK mapping cyclic prefix insertion R(n) pilot symbol insertion s(k) h(k) channel data parallel to serial decision r(k) ^ IFFT FDE FFT cyclic prefix removal r(k) AWGN n(k) channel estimation 39

40 BER 1.E+00 1.E-01 1.E-02 1.E-03 1.E db OFDM QPSK-SC Ts=0.001 sec, K=64 T=0.064 sec QPSK ZF Ts=0.001 sec, K=64 MMSE 1.E Avg. Eb/N0 db 40 Nagoya Institute of Technology

41 amplitude 1.E+01 1.E+00 1.E-01 1.E-02 1.E-03 OFDM QPSK-SC root-rolloff 0.5 QPSK-SC non-lpf Ts=0.001 sec, K=64 T=0.064 sec QPSK Ts=0.001 sec, K=64 1.E-04 1.E f Hz

42 peak to average power ratio CCDF 1.0E E E-02 QPSK-SC OFDM Ts=0.001 sec, K=64 T=0.064 sec QPSK Ts=0.001 sec, K=64 root-nyquist LPF, = E PAPR (db) CCDF: complementary cumulative distribution function 42

43 OFDM-FDESC-FDE OFDM-FDE SC-FDE sinc 43

44 OFDM SC-FDE (single carrier-fde)ofdm PAPR 44

45 probability density f unction Box-Muller amplitude amp_n probability density function radian / pi 45 rad_n

46 N 0 T sec -N/(2T) 0 N/(2T) Hz KTs sn sk, T KT s s s f s 2T 2T s s N 46

47 2 Eb/N0 db E 2 C S A k b QPSK 2 N N 2 BT n s N 0 B n T s =1 2 2 A 2k ( E / N db) b 0 47

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