瑞利衰减在Matlab环境下的源代码.doc

% clear all variablesclear;sig_num = 300;fd = 1;fs = 7;N = 64;fm = 10; %unit: 1HzRs = 1; %unit: 1MHzTs = 1/Rs;% generate random QPSK signalqpsk_D=randint(sig_num,1,4);qpsk_C=dmodce(qpsk_D,fd,fs,psk,4);qpsk_flt = rcosflt(qpsk_C,fd,fs);% draw eye diagram and scatter plot of QPSK signalqpsk=qpsk_flt(1+3*fs:end-3*fs);%eyediagram(qpsk,2*fs,2*fs);%scatterplot(qpsk,fs);% QPSK signal passes through AWGN channelsnr=8;qpsk_AWGN_C=awgn(qpsk_C,snr);qpsk_AWGN_flt=rcosflt(qpsk_AWGN_C,fd,fs);qpsk_AWGN=qpsk_AWGN_flt(1+3*fs:end-3*fs);%eyediagram(qpsk_AWGN,2*fs,2*fs,0,r-);%scatterplot(qpsk_AWGN,fs,0,r.);% generate Doppler power spectrumdeltaf = 2*fm/(N-1);T = 1/deltaf;sf0 = 1.5/(pi*fm);for n = 1:(N-2)/2 sf(n) = 1.5/(pi*fm*sqrt(1-(n*deltaf/fm)2);endclassicf = fliplr(sf),sf0,sf;%figure;%plot(classicf);for channels = 1:3 % generate two normally distributed random variablesgaussN_re1 = randn(1,(N-2)/2); gaussN_im1 = randn(1,(N-2)/2); gaussN_pos1 = gaussN_re1 + i*gaussN_im1;gaussN_neg1 = conj(gaussN_pos1);% gaussN1 = fliplr(gaussN_pos1),0,gaussN_pos1;gaussN1 = fliplr(gaussN_neg1),0,gaussN_pos1;% gaussN_pos2 = randn(1,(N-2)/2);% gaussN2 = fliplr(gaussN_pos2),0,gaussN_pos2;gaussN_re2 = randn(1,(N-2)/2); gaussN_im2 = randn(1,(N-2)/2); gaussN_pos2 = gaussN_re2 + i*gaussN_im2;gaussN_neg2 = conj(gaussN_pos2);gaussN2 = fliplr(gaussN_neg2),0,gaussN_pos2;% generating flat Rayleigh fading channelx = ifft(sqrt(classicf).*gaussN1);y = ifft(sqrt(classicf).*gaussN2);%rayleigh_amp = sqrt(abs(x).2+abs(y).2);%rayleigh_db = 10*log10(rayleigh_amp);%figure;%plot(rayleigh_db);rayleighOrg = x+i*y;% frequency matchingrepNum = round(T*1e6/(Ts*fs);dotNeed = floor(sig_num*fs/repNum);for k = 1:dotNeed for j = 1:repNum rayleighCh(k,j) = rayleighOrg(k); endendremain = sig_num*fs-dotNeed*repNum;if remain 0 for j=1:remain rayleighCh(dotNeed+1,j) = rayleighOrg(dotNeed+1); endend if channels = 1 rayleighCh1 = reshape(rayleighCh,1,); elseif channels = 2 rayleighCh2 = reshape(rayleighCh,1,); else rayleighCh3 = reshape(rayleighCh,1,); end %clear temporary variants for next use clear gaussN_re1 gaussN_im1 gaussN_re2 gaussN_im2 gaussN_neg1 gaussN_neg2; clear gaussN_pos1 gaussN_pos2 gaussN1 gaussN2; clear x y rayleighOrg rayleighCh;end% generate 3-path Rayleigh channela0 = 0.476;a1 = 0.048;a2 = 0.476;% add delay time of Rayleigh channeldelay1 = 1; %unit: 1usdelay2 = 2;r1 = round(delay1/Ts*fs);r2 = round(delay2/Ts*fs);rayleigh0 = a0*rayleighCh1(1:fs*sig_num);rayleigh1 = a1*rayleighCh2(1:fs*sig_num);rayleigh2 = a2*rayleighCh3(1:fs*sig_num);signal = reshape(qpsk_C,1,fs*sig_num);sig_delay1 = zeros(1,r1),signal(1:fs*sig_num-r1);sig_delay2 = zeros(1,r2),signal(1:fs*sig_num-r2);sig_ray0 = signal.*rayleigh0;sig_ray1 = sig_delay1.*rayleigh1;sig_ray2 = sig_delay2.*rayleigh2;% output of 3-path rayleigh channelssig_ray = sig_ray0+sig_ray1+sig_