untitled_qpsk.m

Hybrid DS-FH communication systems

clear all
N=10^3;
tx_sym=1+j;
M=4;
n=[0:M-1];
p=[0:5:35];
count1=zeros(1,36);
count2=zeros(1,36);
for EbNo_dB=0:5:25
    Gno=1/sqrt(2)*10^(-EbNo_dB/20);

    
    for   i=1:N
          y=zeros(1,M);
          z1=zeros(1,M);
          noise=(randn(1,M)+j*randn(1,M))*Gno;
    for   k=0:M-1
          y=y+(1/sqrt(M))*tx_sym*exp((j*2*pi*k.*n)/M);
       
    end
    h = 1/sqrt(2)*[randn(1,1) + j*randn(1,1)];
    sig_no=h.*y+noise;
    sig_no1=sig_no.*conj(h)
    for k=0:M-1
       z1=z1+(1/sqrt(M))*sig_no1(k+1)*exp((-j*2*pi*k.*n)/M);
    end
   
   
   for t=1:M
       if (real(z1(t))<0)
       count1(EbNo_dB+1)=count1(EbNo_dB+1)+1;
       end
       
       if (imag(z1(t))<0);
       count2(EbNo_dB+1)=count2(EbNo_dB+1)+1;
       end
   end
   end
end

tmp_ber=(count1+count2)/2/(4*N);
ber=tmp_ber(1,1:5:end);
semilogy(p,ber,'mx-','linewidth',2); 
axis([0 25 10^-5 0.5])
grid on