viterbi_encoder.m

依据GSM 05.03建议

function [channel_input]=viterbi_encoder(G,k,coder_input)
%k for input number
channel_input=[];

%n for output number
n=size(G,1);
G_2=size(G,2);

if rem(size(G,2),k)~=0
   error('Size of G and k do not agree')
end
if rem(size(coder_input,2),k)~=0
   error('Size of Input and k do not agree')
end

depth_of_input=length(coder_input)/k;

%header
for i=1:size(G,2)/k-1
   input_matrix=[coder_input(i*k:-1:1),zeros(1,size(G,2)-i*k)];
   gg_out=G*input_matrix';
   for l=1:n
      channel_input(n*(i-1)+l)=rem(gg_out(l),2);
   end
end

%body
for i=size(G,2)/k:depth_of_input
   input_matrix=[coder_input(k*i:-1:k*i-G_2+1)];
   gg_out=G*input_matrix';
   for l=1:n
      channel_input(n*(i-1)+l)=rem(gg_out(l),2);
   end
end

%tailer
for i=(G_2/k-1):-1:1
   input_matrix=[zeros(1,G_2-i*k),coder_input(depth_of_input*k:-1:(depth_of_input-i)*k+1)];
   gg_out=G*input_matrix';
   for l=1:n
      channel_input(n*(G_2/k-i-1)+l+depth_of_input*n)=rem(gg_out(l),2);
   end
end