mrcbpsk1x4.m

1x4 MRRC space time coding using BPSK

 clear all
SNRdb=[0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30];  
k=100;
%The graph will be drawn using different SNR values.
for i=1:length(SNRdb)                                                                     %The Program will continue computing for these different values. 
    sigma=sqrt(10^(-SNRdb(i)/10));                                                              %N0 variance of the noise will be computed.
    Ber2(i)=0;
    
    for run=1:10000    
        %The choose of 'run' value is 
         s0=(sign(randn(1,k)))./sqrt(2);

        H0=((randn(1,k))+j*(randn(1,k)));
    H1=((randn(1,k))+j*(randn(1,k)));
     H2=((randn(1,k))+j*(randn(1,k)));
    H3=((randn(1,k))+j*(randn(1,k)));

    N0=(sigma*((randn(1,k))+j*(randn(1,k))))./sqrt(2);
    N1=(sigma*((randn(1,k))+j*(randn(1,k))))./sqrt(2);
        N2=(sigma*((randn(1,k))+j*(randn(1,k))))./sqrt(2);
    N3=(sigma*((randn(1,k))+j*(randn(1,k))))./sqrt(2);

    r0=H0.*s0+N0;
    r1=H1.*s0+N1;
    r2=H2.*s0+N2;
    r3=H3.*s0+N3;

    %ML
    Shat=conj(H0).*r0+conj(H1).*r1+conj(H2).*r2+conj(H3).*r3;
    
    S0hat=(sign(real(Shat)))./sqrt(2);
    
    Error=(sum(s0~=S0hat));
    Ber2(i)=Ber2(i)+Error./(k);

    
    
    
    
    end
end
Ber2=Ber2/run
semilogy(SNRdb,Ber2,'-*');title('BER Characteristic of QPSK Modulated Signals for Different SNR');
xlabel('E_b/N_0 (dB)');ylabel('BER (P_e)');grid;