1自相關判決函自相關判決函19

采樣點索引號SNR=20dB1數(shù)數(shù)函相關函相關0 采樣點索引13-20SNR=0dB s_longi;i0,1,,L T2m

mn

s_long

51kkk211數(shù)數(shù)函函0 采樣點索引號21AGC信號13-53xsign(Rex)jsign(x)

5253 22

211數(shù)數(shù)函函0 采樣點索引號22FFT13.3.3xkskxk

54frx

rkxkej2ftxkTSej2frxkTSxkej2fkTSxk

Lj2D j2D LRrkrkDk

NxkxkDk

Nxkk0

56N

N

5713-57N DN D

L

102000Hz

L

D

L48

23L點求 求相 求頻DD整23 23

NCO

QPSK

NCO5005iOFDM

Yi,kPi,kHi,ke

58RYi,k(Pi,kHi,k)ejPi,kHi,k QPSK

5925

OFDMNNNN50 13-25OFDMQPSK

2000HzFFT250Hz

FFTOFDM125HzOFDMOFDMOFDM系統(tǒng)的編碼算

/13-2626nnnn2qQQQQQQQQ26

Q{y0,y1,..., Q…MQ

{x0,x1,...,001X PY1v1,Y2v2,...,YnvnX1u1,X2u2,...,XnunnPYkvkXkukk

60

13-26DiscreteMemoryless{x0,x1,...,xq1} Y{y0,y1,..., Pyixj PyixjPYyiXxj

61X

xjyilogPyixj/PyiPyiPYyiPxkPyixkk

Y

62YYI(X;Y)PxjPyixjj0Pxj

PyixjPyiPxj I(X;Y

63PyixjPyixj CmaxI(X;YPxI(X;Y)

q1PxmaxPxjPyixPxjj0Pxj

PyixjPyi

6463

2j2

Pxj

65bit/symbol nat/symbol // bit/snat/s

I(X;Y Pxj 對于所有滿足Pxj的I(x;Y)? 對于所有滿足Px的

66I(xj;Y)Pyixj

PyixjPyi

67Pxj

C PavW

WN0

68Shannon1948BlockCodingConvolutionalCodingnnnnn(nn(n,kCi

(n,k)1Ci

HammingHadamardGolaynBCHnKnnTurboCOFDM系統(tǒng)模OFDMOFDMCOFDM

OFDM

COFDMCodedOFDM

FECKn213-27n K k21 K k2112k12k 12k27 Rck/ nn時也是—個決定編碼復雜程度的重要參數(shù)矩陣，因為輸入序列是半無限長度的。另一種描述卷積碼的方法是用一組nn2n1n n2K13-28K=3 k=1nRc=1/213-28K=3 Rc11 12 [111]，g2[101]13-2813-29

12 (7,5) 13-29K=3 Rc 2292K=330t=0 l=3廣4I=5 I=8尸9尸10尸II勹13-30K=3k=1 0144431State `又一一一一一一一一一一一一一一一一一二StateStateState13-31K=3k=1n=2 Re=1/21nkK-1nknnK-

kK-k

K-nn00····· 00FlushingnViterbiViterbiAndrewJ.Viterbi1967IEEETransactionsonInformationTheoryErrorBoundsforConvolutionCodesandAnAsymptoticalOptimumDecodingAlgorithmViterbi

iVSj,i

KViterbiK?9VS0,00，i1VSj,i S SLi<Li<L+i=ii=L+HammingEuclideanK=3 k=1 n=2Rc1/2ViterbiHamming32 t=0t=1t=2t=3t=4t=5t=6t=7t=8t=9t=10t=11t=12t=13t=14t=15t=16StateStateStateStateENCIN=1011100101000100ENCOUT=RECEIVED=ERRORS13-32K=3 Rc3232 AccumulatedErrorMetricHamming01213-33t112 0t0

02StateStateStateState

t=0

Error02ENCIN=0ENCOUT=RECEIVED=t14334

0000

Error ENCIN=1ENCOUT=RECEIVED=t2348的 t t8的 1111 10 10State01StateENCIN=10ENCOUT=RECEIVED=

t=0

t=2

Errort335150% 10StateStateStateState

t=0 t=3

ErrorENCIN=101ENCOUT=RECEIVED=36

t4

t3 32 1111111111101000 01 StateState

t=0 t=3

ErrorMetric=StateENC=1011ENCOUT=00RECEIVED=

(K,k,n)2k(K

t

2k(K1)2k(K

VitetbiK與

VitetbiBurton/Interleaving

BlockInterleaving RamseyForney OFDM通信系統(tǒng)設382倍升采加循環(huán)前2倍升采加循環(huán)前調卷積碼編數(shù)字上變13-38OFDM1k=1 G=[1011011;1111001]901

1/211920 81QPSK13-

PAPR13-1QPSK1,--1,-1,--1-106

89610PS

106128PAPR

Nyquist128 128 64IFFTIFFT2.56MHz102CIC7I CIC13-3920I基帶處理后的數(shù)Q39FIR22FIRFIR13-40xxnz-xn-z-xn-z-xn-M13-40FIR20kHz

100dB/ FIR1913-2FIR 4113-23FIR00---------

Frequency13-4119FIRCIC

20CICE.B.HogenauerHogenauer

1zRM RM HzHNzHNz 1 1z k 13-42CIC

69R20,M1,N 13-43DDSDDS

DirectDigitalSythesisDDSDDS13-43 ROMD/A ·· 解·· 解 織后··轉換···后··轉換···FFT開窗控頻糾控補 FFT

OFDM

313-3OFDM通信系統(tǒng)仿真參/ViterbiOFDM32IFFT/FFT320AWGNOFDM 450-誤碼率-誤碼率-- 信噪比13-45OFDMOFDM通信系統(tǒng)仿真程OFDM %OFDM%FFTPAPR%clearallcloseall% % % % % %m_syn globalseq_numglobalcount_dds_downglobaldingshiglobal% % % % % % Hz% %G G=[1011011;1111001 forseq_num=1:frame_num,%frame_numifseq_num<3ifseq_num==1elseifseq_num==2%%%%%% % 0.296360.39560.29636 %128kHz20kHz40kHz1dB100dB% %++++++++++++++++++++++++++++fir++++++++++++++++++++++++guiyi_b=[0.019527-0.03934 0.5944-0.1003-%60dBifseq_num<3ifseq_num>2 %%%xlabel('')for

xlabel('/dB')ylabel('')grid% %cnv_encd(G,k0,input),k0bit%Gn0L*k0n0bitn0%GLL%%(n0,k0,m)m=(L-1)*k0%%L-10m=L*k0inputk0% %%%

bitifrem(length(input),k0)>0%Gk0iferror('Error,Gisnotoftherightsize.')% %000(L-1)*k0%uu%0L*k0k0%1L*k01+k0L*k0+k0%fori=1:n+L-2%G*uufunction% % % % % for%QPSKfunction% % fori=1:length(din)/2,%%%0%[100140%%%0%[100140%0%IFFT16%ifseq_num==1fbconnection=[100elseifseq_num==2fbconnection=[1000001];forififmod(k-1,16)==0 %16elseifseq_num==2m%mfunction[mseq]=% % n=length(fbconnection);N=2^n-1;register=[zeros(1,n-1)1];%mseq(1)=register(n);fori=f