cm_sm32_golay.m

这个程序是仿真计算加golay编码的bpsk的ber计算

function [pb1]=cm_sm32_golay(EbNo)
% [pb1]=cm_sm32_golay(EbNo)
%                CM_SM32_golay finds the probability of bit error for 
%                the given value of EbNo(dB).
%
% 
%
N=5000;
E=1;                                            % energy per symbol
snr=10^(EbNo/20);                               % EcNo
sgma=sqrt(E/(2*snr));                           % noise variance
%************* generation of the data source
dsource=zeros(N,24);
dsource1=zeros(N,24);
numofbiterror=0;
for i=1:N,
%************* Generator 12 bits information bits used to generate golay code
    C=rand(1,12)>0.5;
    [codeword]=golay24_encode(C);
%********** Generate 24 bits golay code
    dsource(i,:)=codeword;     
    dsource1(i,:)=codeword;
    temp=dsource(i,:);
    for j=1:24                          %0->1,1->-1
        if (temp(j)==0)
            dsource(i,j)=1;
        else
            dsource(i,j)=-1;
        end                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         
    end
end
%********** detection and the probability of error calculation

for i=1:N,
    %********** the received signal at the detection, for the ith symbol,is:
    s=dsource(i,:);
    n=sgma*randn(1,24);                          % 1*24 normal distributed r.v with 0, variance sgma
    ss=s+n;
    for j=1:24
        if (ss(j)>=0)
            s(j)=0;
        elseif (ss(j)<0)
            s(j)=1;
        end
    end
    %disp(s);
%********* Decode the 24 bits codeword after the demoduationg of bpsk
    [final_data]=golay24_decode(s);
    %decis(i)=final_data;
    decis=xor(dsource1(i,:),final_data);
    %disp(decis);
%******** Calculate the number of error bits
    if (sum(decis))
       numofbiterror=numofbiterror+sum(decis); 
    end
end
pb1=numofbiterror/(24*N);             %since 24*N bits are transmitted