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OFDM SC-FDE (single carrier-fde)ofdm PAPR 3
OFDM SC-FDE (single carrier-fde)ofdm PAPR 4
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Mobility 2G GSM PDC PHS 3G WCDMA cdma2000 WLAN IEEE802.11b 4G 20112013 WLAN IEEE802.11g, n BWA 10kbps 2Mbps 10Mbps 100Mbps 1Gbps 6
C B log 2(1 S Hz / N ) bit/sec AWGN 7
OFDM SC-FDE (single carrier-fde)ofdm PAPR 8
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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
h(, t) t s(t) h(,t) n(t) r(t) rt () h(,) t st () nt () H(f, t) 12
h(, t) h(, 0) received power (db) s(t) h(,t) n(t) r(t) 0 1 2 3 4 delay time (s) h(, 1) received power (db) 0 1 2 3 4 delay time (s) 13
OFDM SC-FDE (single carrier-fde)ofdm PAPR 14
h(,) t c() t () t Jakes received power (db) c(t)(t) 0 1 2 3 4 delay time (s) n v m/s (vcosn)/ Hz m 15
cos(2f 0 t)+cos(2{f 0 +f}t) 2 1 0-1 -2-10 -8-6 -4-2 0 2 4 6 8 10 f 0 =1, f=0.075 1.E+01 c(t) amplitude 1.E+00 1.E-01 1.E-02 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 t sec 16
or s(t) c(t) n(t) r(t) rt () ctst () () nt () 17
c(t) NLOS (non-line-of-sight) 2 r r f( r) exp r 2 2 2 2 2 c(t) LOS (line-of-sight) 2 2 ( ) r exp r a ar f r I 2 2 0 2 2 a I 0 18
1.E+01 1.E+00 fd Hzv m/s f0 Hzc f d vf c f d 0 1 0.5 fdts=0.001 fdts=0.005 fdts=0.01 amplitude 1.E-01 1.E-02 1.E-03 0 0.2 0.4 0.6 0.8 1 time sec fdts=0.001 fdts=0.005 fdts=0.01 phase / pi 0-0.5-1 Ts=0.001 sec Ts 0 0.2 0.4 0.6 0.8 1 time sec 19
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
c(t) ZF rk ( ) nk ( ) rk ( ) sk ( ) ck ( ) ck ( ) MMSE * c k ( ) rk ( ) rk ( ) ck ( ) E sk ( ) 2 2 2 rk ( ) cksk ( ) ( ) nk ( ) sk ( ) rk ( ) nk ( ) 2 rk ˆ( ) ck ( ) k c(t)c(f)lpf 21
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 0 10 20 30 40 50 Avg. Eb/N0 db 22
OFDM SC-FDE (single carrier-fde)ofdm PAPR 23
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
Ts received power (db) 0 1 2 3 4 delay time (s) received power (db) trans. rate = 250 Kbps Ts= 4 s delay time (s) 0 1 2 3 4 delay time (s) 0 4 received power (db) trans. rate = 3.84 Mbps Ts= 0.26 s 25
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 9 0 0 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-03-500 -400-300 -200-100 0 100 200 300 400 500-500 -400-300 -200-100 0 100 200 300 400 500-500 -400-300 -200-100 0 100 200 300 400 500 f Hz f Hz f Hz 26
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
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 ( ) 2 2 2 28
OFDM SC-FDE (single carrier-fde)ofdm PAPR 29
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
I-channel 1 0.8 0.6 0.4 0.2 0-0.2-0.4-0.6-0.8-1 0 0.02 0.04 0.06 0.08 0.1 0.12 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-05-4000 -3000-2000 -1000 0 1000 2000 3000 4000 f Hz 31
peak to average power ratio 32
1 OFDM 1 K 0 Ts sec 0 Ts sec 1 1 T=KTs sec Ts TsT 33
ISI: inter-symbol interference OFDM1 K OFDM GI: guard interval OFDM1 K 34
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
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-05 0 5 10 15 20 25 30 35 Avg. Eb/N0 db 36
h 2 h 3 h4 h(t,) [db] h 0 h 1 h 5 h 6 h 7 h8 h9 37 0 1 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
OFDM SC-FDE (single carrier-fde)ofdm PAPR 38
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
BER 1.E+00 1.E-01 1.E-02 1.E-03 1.E-04 10.5 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-05 0 5 10 15 20 25 30 35 Avg. Eb/N0 db 40 Nagoya Institute of Technology
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-05-4000 -3000-2000 -1000 0 1000 2000 3000 4000 41 f Hz
peak to average power ratio CCDF 1.0E+00 1.0E-01 1.0E-02 QPSK-SC OFDM Ts=0.001 sec, K=64 T=0.064 sec QPSK Ts=0.001 sec, K=64 root-nyquist LPF, =0.5 1.0E-03 2 4 6 8 10 12 PAPR (db) CCDF: complementary cumulative distribution function 42
OFDM-FDESC-FDE OFDM-FDE SC-FDE sinc 43
OFDM SC-FDE (single carrier-fde)ofdm PAPR 44
probability density f unction 1 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0 Box-Muller 0 0.5 1 1.5 2 2.5 3 amplitude amp_n probability density function 0.2 0.18 0.16 0.14 0.12 0.1 0.08 0.06 0.04 0.02 0-1 -0.5 0 0.5 1 radian / pi 45 rad_n
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
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 10 0.1 ( E / N db) b 0 47
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