function Rout=SISO(y_s,y_h,m_max,p,H,noise_std)
%m為第幾個(gè)單元譯碼器，mmax為迭代次數(shù),r_s為輸入軟判決碼字,r_h為硬輸入碼子，硬輸出碼字D,碼字集合C
%H為輸入校驗(yàn)矩陣，noise_std為輸入噪聲方差，W為輸出外信息，R為軟輸出，DD為本次單元譯碼的硬輸出碼子
%根據(jù)迭代次數(shù)，采用自適應(yīng)方法確定調(diào)節(jié)系數(shù),但要防止調(diào)節(jié)系數(shù)發(fā)散，
%同時(shí)為了減少譯碼復(fù)雜度，用梯度算法簡化外信息的計(jì)算
 %-----------------------------計(jì)算外信息---------------------------------
 %------------為使譯碼復(fù)雜度降低不去尋找競爭碼字,采用梯度算法-----------------
 R_soft=y_s;
 R_hard=y_h;
 [M,N]=size(y_s);
 %********************************************************
for m=1:m_max
%----------initialize---------------------------------
%  行譯碼
 for ii=1:M
     r_s=R_soft(ii,:);
     r_h=R_hard(ii,:);
     RR(ii,:)=r_s,
     B(m)=m/m_max,
    switch(m)
       case 1,
            RRi(ii,:)=RR(ii,:);
            W(ii,:)=zeros(1,N);,
            A(m)=0,
            D(ii,:)=chase(p,r_s,r_h,H),
            W(ii,:)=D(ii,:).*B(m);
            RRout(ii,:)=RRi(ii,:)+W(ii,:);
       otherwise,
          A(m)=(m*(noise_std^2))/var(W(ii,:)),
           for j=1:N
           RRi(ii,j)=r_s(j)+W(ii,j).*A(m),
           end
           D_f=D(ii,:);
          D(ii,:)=chase(p,r_s,r_h,H),
          xishu=0,
          for j=1:N
              xishu=xishu+((RRi(ii,j)-D_f(ii,j))^2-(RRi(ii,j)-D(ii,j))^2),
          end
           xishu=xishu/4;
         for i=1:N
             if D(ii,i)==D_f(ii,i)
                 W(ii,i)=B(m)*D(ii,i);
                 RRout(ii,i)=RRi(ii,i)+W(ii,i);
             else
                 W(ii,i)=xishu*D(ii,j)-RR(ii,i);
                 RRout(ii,i)=RRi(ii,i)+W(ii,i);
             end
         end
     end
 end
 %------------------------------------------------------------------------
%  解交織
R_soft=R_soft';
R_hard=R_hard';
W=W'
%-------------------------------------------------------------------------
%---------------------------列譯碼-----------------------
 for ii=1:M
     r_s=R_soft(ii,:);
     r_h=R_hard(ii,:);
     RR(ii,:)=r_s,
     B(m)=m/m_max,
    switch(m)
       case 1,
            RRi(ii,:)=RR(ii,:);
            W(ii,:)=zeros(1,N);,
            A(m)=0,
            D(ii,:)=chase(p,r_s,r_h,H),
            W(ii,:)=D(ii,:).*B(m);
            RRout(ii,:)=RRi(ii,:)+W(ii,:);
       otherwise,
          A(m)=(m*(noise_std^2))/var(W(ii,:)),
           for j=1:N
           RRi(ii,j)=r_s(j)+W(ii,j).*A(m),
           end
           D_f=D(ii,:);
          D(ii,:)=chase(p,r_s,r_h,H),
          xishu=0,
          for j=1:N
              xishu=xishu+((RRi(ii,j)-D_f(ii,j))^2-(RRi(ii,j)-D(ii,j))^2),
          end
           xishu=xishu/4;
         for i=1:N
             if D(ii,i)==D_f(ii,i)
                 W(ii,i)=B(m)*D(ii,i);
                 RRout(ii,i)=RRi(ii,i)+W(ii,i);
             else
                 W(ii,i)=xishu*D(ii,j)-RR(ii,i);
                 RRout(ii,i)=RRi(ii,i)+W(ii,i);
             end
         end
     end
 end
%-------------------------------------------------------------
 
%  解交織
R_soft=R_soft';
R_hard=R_hard';
W=W'
%------------------------------------------------------------ 
 for i=1:M
     for j=1:N
 Rout(i,j)=RRout(i,j);
     end
 end
%  Rout=9;