%rank is coming ou to be 4clc;clear all;close all;snr_dB = [1:10]; % multiple Eb/N0 valuessnr = 10.^(snr_dB /10);%snr nTx = 4; %number of transmittersnRx = 1; %number of receiversT=4; %time symbolN=4; %number of symbolsa=nTx*T;l=100; %number of realizations of AA = (rand(a,N,l)+ 1j*rand(a,N,l)) ;for l1= 1:100 ran = rank(A(:,:,l1)); if ran == 4 [Znew(:,:,l1),R(:,:,l1)]=qr(A(:,:,l1),0); Z(:,:,l1) =sqrt(T/N) * Znew(:,:,l1); M(:,:,:,l1)=reshape(Z(:,:,l1),[nTx,T,N]); endendconsat=0;e=0.1;for l1=1:100 con=(Z(:,:,l1))'* Z(:,:,l1); if abs(det(con - ((T/N)*eye(N)))) < e consat =consat +1; l2(consat)=l1; endend%qpsk symbol generationsx_q=[-1 -1 1 1]; y_q=[1 -1 1 -1];QPSK_s=x_q+y_q*i;QPSK_r=QPSK_s;nofbit = 1000; tot_bits1=round(rand(1,nofbit));bitsnt = tot_bits1(1:N*2);for symbl = 1: N s(symbl) = QPSK_s(bi2de(bitsnt((2*symbl-1):(2*symbl)),'left-msb')+1);ends1=reshape(s,N,1);snrj = 10; for var2 = 1:consat dif(:,:,var2) = zeros(nTx,T); %channel H = 1/sqrt(2)*[rand(nRx,nTx)+ 1j*(rand(nRx,nTx))]; % Rayleigh channel Noise = sqrt(2)* [rand(nRx*nTx,1)+ 1j*(rand(nRx*nTx,1))] .*(1 / sqrt(snrj)); H1 = kron (eye(T),H);%modified rayleigh chanel Y= H1 *Z(:,:,l2(var2))*s1 + Noise ; shat = Z(:,:,l2(var2))' * H1' * Y ; %find for S1 corresponding bits for recsym = 1: N [H2,I]=min(QPSK_s-shat(recsym)); shatdec(recsym) = QPSK_s(I); end shatdecr = reshape(shatdec,N,1); for m=1:N dif(:,:,var2) = dif(:,:,var2) + M(:,:,m,var2) .* (s1(N)-shatdecr(N)); end R(:,:,var2) = conj(dif(:,:,var2)) * (dif(:,:,var2))'; rk(var2)=rank(R(:,:,var2)); [U,dia,V]=svd(R(:,:,var2)); dia if rk(var2) == nTx J(var2)=det(dia .* rk(var2)) ; end if rk(var2) < nTx J(var2 ) = 0; end endJ[h4, Index] = max(J);IndexN1 = 1;gg = ones(1,N1);Z11 =Kron( gg ,Z(:,:,Index));snri = 1:5:26;errortotal = zeros(1,length(snri));for df=1:length(snri) errrtotal = 0; for par = 1:100 n_bits = randi([0,1],1,N*N1); h= modem.qammod(4); hd = modem.qamdemod(4); H = 1/sqrt(2)*[rand(nRx,nTx)+ 1j*(rand(nRx,nTx))]; % Rayleigh channel H1 = kron (eye(T),H);%modified rayleigh chanel snew = modulate( h, n_bits); s1=reshape(snew,N*N1,1); Y1= H1 *Z11*s1; Y = awgn(Y1 , snri(df)); shat = Z11' * H1'* Y ; for recsym = 1: N*N1 [H21,In]=min(QPSK_s-shat(recsym)); dec_bit(recsym) = demodulate(hd,QPSK_s(In)); end ratio = (sum(n_bits ~= dec_bit))/(N*N1); errrtotal = errrtotal + ratio ; end errorsnr(df) = errrtotal / par; dfend semilogy(snri,errorsnr);