bperuncode2pskm2.m

无线通信系统中的空时编码的仿真程序。多天线发送

function [pb,ps]=bperuncode2pskm2(snr_in_dB,N)
E=1;                                           %energy per symbol
snr=10^(snr_in_dB/10);
numan=1;                                       %the number of transmit antennas
M=2;
L=log(M)/log(2);
sgman=sqrt(E*numan/(2*snr));                   %noise variance
sgmaa=sqrt(0.5);
for k=1:N,
    temp=rand;
    dsource(k)=1+floor(M*temp);                % a integer number between 1 and M, uniform       
end;
mappingbits=[ 0;
              1];
mapping=[1;
     -1];                                      %2PSK
 for k=1:N,
     bpsk_sig(k)=mapping(dsource(k));
     dsourcebits(k,:)=mappingbits(dsource(k),:);
 end;
 for k=1:N,                                     %received signal
     [a(1) a(2)]=gngauss(sgmaa);                %path gain   receive antenna 1
     [a(3) a(4)]=gngauss(sgmaa);                %path gain   receive antenna 2
     [n(1) n(2)]=gngauss(sgman);                %noise   receive antenna 1
     [n(3) n(4)]=gngauss(sgman);                %noise   receive antenna 2
     r1(k)=bpsk_sig(k).*(a(1)+a(2).*i)+(n(1)+n(2).*i); % received signal on receive antenna 1
     r2(k)=bpsk_sig(k).*(a(3)+a(4).*i)+(n(3)+n(4).*i); % received signal on receive antenna 2
     for j=1:M,
         s1(k,j)=mapping(j).*(a(1)+a(2).*i);
         s2(k,j)=mapping(j).*(a(3)+a(4).*i);
     end;
 end;
 numofsymbolerror=0;
 numofbiterror=0;
 for k=1:N,
     for j=1:M,
         metrics1(j)=(abs(r1(k)-s1(k,j))).^2;
         metrics2(j)=(abs(r2(k)-s2(k,j))).^2;
     end;
     [min_metric decis]=min(metrics1+metrics2);
     decisbits(k,:)=mappingbits(decis,:);
     for l=1:L,
         if (decisbits(k,l)~=dsourcebits(k,l)),
             numofbiterror=numofbiterror+1;
         end;
     end;
     if (decis~=dsource(k)),
         numofsymbolerror=numofsymbolerror+1;
     end;
 end;
 ps=numofsymbolerror/N;
 pb=numofbiterror/(L*N);