极化码的Matlab编解码仿真

function L2 = getL_improve(llr, u, k) % compute L_N^(i) according to llr and % The length of llr is N, the length of u is (i-1) % llr := W(y_i|u_i=0)/W(y_i|u_i=1) global LLr n i = length(u) + 1; N = length(llr); if LLr(i+k-1,n+1-log2(N)) == 0 if (i-1)==0 % u is null if N==1 L2 = llr; else a = getL_improve(llr(1:N/2), [], k); b = getL_improve(llr((N/2+1):N), [], k+N/2); L2 = (a*b+1)/(a+b); LLr(i+k-1,n+1-log2(N)) = L2; end elseif mod(i,2)==0 % even index uo = u(1:2:(i-2)); ue = u(2:2:(i-2)); a = getL_improve(llr(1:N/2), xor(uo,ue), k); b = getL_improve(llr((N/2+1):N), ue, k+N/2); L2 = a^(1-2*u(i-1)) * b; LLr(i+k-1,n+1-log2(N)) = L2; else % odd index uo = u(1:2:(i-1)); ue = u(2:2:(i-1)); a = getL_improve(llr(1:N/2), xor(uo,ue), k); b = getL_improve(llr((N/2+1):N), ue, k+N/2); L2 = (a*b+1)/(a+b); LLr(i+k-1,n+1-log2(N)) = L2; end else L2 = LLr(i+k-1,n+1-log2(N)); end