基于matlab的LDPC译码仿真实验源码.zip

clear x; x=demodz; clear prob0; clear prob1; prob0=zeros(1,lieH); prob1=zeros(1,lieH); for a=1:lieH prob1(1,a)=1/(1+exp(x(1,a)*2/sigma^2)); prob0(1,a)=1-prob1(1,a); end q0=zeros(hangH,lieH); q1=zeros(hangH,lieH); r0=zeros(hangH,lieH); r1=zeros(hangH,lieH); for i=1:lieH for jo=1:liezhong q0(ncol(jo,i),i)=prob0(1,i); q1(ncol(jo,i),i)=prob1(1,i); end end for lp=1:20 for i=1:hangH for jo=1:hangzhong delta=1; for l=1:hangzhong if l~=jo delta=delta*(1-2*q1(i,nrow(i,l))); end end r0(i,nrow(i,jo))=0.5+0.5*delta; r1(i,nrow(i,jo))=1-r0(i,nrow(i,jo)); end end for i=1:lieH for jo=1:liezhong alpha1=1; alpha2=1; alpha3=1; alpha4=1; for l=1:liezhong if l~=jo alpha1=alpha1*r0(ncol(l,i),i); alpha2=alpha2*r1(ncol(l,i),i); end end %--------------------------------------------------- if (prob0(1,i)*alpha1+prob1(1,i)*alpha2)==0 alpha3=1; else alpha3=1/(prob0(1,i)*alpha1+prob1(1,i)*alpha2); end %---------------------------------------------------- q0(ncol(jo,i),i)=alpha3*prob0(1,i)*alpha1; q1(ncol(jo,i),i)=alpha3*prob1(1,i)*alpha2; end end Q0=zeros(1,lieH); Q1=zeros(1,lieH); for i=1:lieH delta1=1; delta2=1; for jo=1:3 delta1=delta1*r0(ncol(jo,i),i); delta2=delta2*r1(ncol(jo,i),i); end if (prob0(1,i)*delta1+prob1(1,i)*delta2)==0 delta3=1; else delta3=1/(prob0(1,i)*delta1+prob1(1,i)*delta2); end Q0(1,i)=delta3*prob0(1,i)*delta1; end decoded=zeros(1,lieH); for i=1:lieH if Q0(1,i)<0.5 decoded(1,i)=1; end end clear check; check=H*decoded'; biaozhi=0; for i=1:hangH if mod(check(i,1),2)==1 biaozhi=1; break; end end if biaozhi==0 break; end end