bper2pskg2.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]=bper2pskG2(snr_in_dB,N)
E=1;                                           %energy per symbol
snr=10^(snr_in_dB/10);
numan=2;                                       %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;
dsource1=[dsource(1:N/2)];
dsource2=[dsource((N/2+1):N)];
mappingbits=[0;
             1];
mapping=[1;
         -1];               %4PSK
 for k=1:N,                                     %mapping symbol and bits
     bpsk_sig(k)=mapping(dsource(k));
     dsourcebits(k,:)=mappingbits(dsource(k),:);
 end;
 bpsk_sigkrate=[bpsk_sig(1:(N/2));bpsk_sig((N/2+1):N)];
 dsourcebits1=dsourcebits((1:(N/2)),:);
 dsourcebits2=dsourcebits(((N/2+1):N),:);
 for k=1:(N/2),                                 %each frame 2antennas 2time slots
     [a(1) a(2)]=gngauss(sgmaa);                %path gain antenna1
     [a(3) a(4)]=gngauss(sgmaa);                %path gain antenna2
     pathgain=[(a(1)+a(2).*i);
               (a(3)+a(4).*i)]; 
     [n(1) n(2)]=gngauss(sgman);                %noise timeslot1
     [n(3) n(4)]=gngauss(sgman);                %noise timeslot2
     noise=[(n(1)+n(2).*i);
            (n(3)+n(4).*i)]; 
     C=[bpsk_sigkrate(1,k),bpsk_sigkrate(2,k);
        -conj(bpsk_sigkrate(2,k)),conj(bpsk_sigkrate(1,k))];
     r(:,k)=C*pathgain+noise;                   %received signals 
     for j=1:M,
         s1(k,j)=(abs((r(1,k)*conj(pathgain(1,1))+conj(r(2,k))*pathgain(2,1))-mapping(j))).^2+...
             (-1+(abs(pathgain(1,1))).^2+(abs(pathgain(2,1))).^2).*(abs(mapping(j))).^2;
         s2(k,j)=(abs((r(1,k)*conj(pathgain(2,1))-conj(r(2,k))*pathgain(1,1))-mapping(j))).^2+...
             (-1+(abs(pathgain(1,1))).^2+(abs(pathgain(2,1))).^2).*(abs(mapping(j))).^2;
     end;
 end;
 numofsymbolerror=0;
 numofbiterror=0;
 for k=1:(N/2),
     [min_metric1 decis1]=min(s1(k,:));
     [min_metric2 decis2]=min(s2(k,:));
     decisbits1(k,:)=mappingbits(decis1,:);
     decisbits2(k,:)=mappingbits(decis2,:);
     for l=1:L,
         if (decisbits1(k,l)~=dsourcebits1(k,l)),
             numofbiterror=numofbiterror+1;
         end;
         if (decisbits2(k,l)~=dsourcebits2(k,l)),
             numofbiterror=numofbiterror+1;
         end;
     end;
     if (decis1~=dsource1(k)),
         numofsymbolerror=numofsymbolerror+1;
     end;
     if (decis2~=dsource2(k)),
         numofsymbolerror=numofsymbolerror+1;
     end;
 end;
 ps=numofsymbolerror/N;
 pb=numofbiterror/(L*N);