cm_sm32.m

基于MATLAB的QPSK的误码率,误符号率图示程序.经调试验可行.

function[pb,ps]=cm_sm32(SNRindB)
N=10000;
E=1;
SNR=10^(SNRindB/10);
sgma=sqrt(E/SNR)/2;
s00=[1 0];
s01=[0 1];
s11=[-1 0];
s10=[0 -1];
for i=1:N
    temp=rand;
    if (temp<0.25)
        dsource1(i)=0;
        dsource2(i)=0;
    elseif (temp<0.5)
        dsource1(i)=0;
        dsource2(i)=1;
    elseif (temp<0.75)
        dsource1(i)=1;
        dsource2(i)=0;
    else 
        dsource1(i)=1;
        dsource2(i)=1;
    end;
end;
numofsymbolerror=0;
numofbiterror=0;
for i=1:N
    n=sgma*randn(size(s00));
    if((dsource1(i)==0)&(dsource2(i)==0))
        r=s00+n;
    elseif((dsource1(i)==0)&(dsource2(i)==1))
        r=s01+n;
    elseif((dsource1(i)==1)&(dsource2(i)==0))
        r=s10+n;
    else
        r=s11+n;
    end;
    c00=dot(r,s00);
    c01=dot(r,s01);
    c10=dot(r,s10);
    c11=dot(r,s11);
    c_max=max([c00 c01 c10 c11]);
    if (c00==c_max)
        decis1=0;decis2=0;
    elseif(c01==c_max)
        decis1=0;decis2=1;
    elseif(c10==c_max)
        decis1=1;decis2=0;
    else
        decis1=1;decis2=1;
    end;
    symbolerror=0;
    if(decis1~=dsource1(i))
        numofbiterror=numofbiterror+1;
        symbolerror=1;
    end;
    if(decis2~=dsource2(i))
        numofbiterror=numofbiterror+1;
        symbolerror=1;
    end;
    if(symbolerror==1)
        numofsymbolerror=numofsymbolerror+1;
    end;
end;
ps=numofsymbolerror/N;
pb=numofbiterror/(2*N);