trellis.m

传统的卷积码和Turbo码直到今天仍有广泛的应用

function state_map=trellis
% function to generate the trellis called state_map here
% row:input:00 01 10 11 00 01 10 11 ...
%     state:0           1           ...
% column:last_state,next_state,output
% state_map=zeros(32,3);
% state_map=[0 0 0;6 7 1;1 4 1;7 3 0;
%            2 4 0;4 3 1;3 0 1;5 7 0
%            5 1 1;3 6 0;4 5 0;2 2 1;
%            7 5 1;1 2 0;6 1 0;0 6 1;
%            1 6 1;7 1 0;0 2 0;6 5 1;
%            3 2 1;5 5 0;2 6 0;4 1 1;
%            4 7 0;2 0 1;5 3 1;3 4 0;
%            6 3 0;0 4 1;7 7 1;1 0 0];

% last_state(4),next_state(4),last_out(12),next_out(12)
state_map=zeros(8,32);
state_map=[0 6 1 7 0 7 4 3 0 0 0 0 1 1 1 0 1 1 1 0 0 0 0 0 1 1 1 0 1 1 1 0;
           2 4 3 5 4 3 0 7 0 0 1 0 1 0 1 0 0 1 1 1 0 0 0 0 1 1 1 0 1 1 1 0;
           5 3 4 2 1 6 5 2 0 0 1 0 1 0 1 0 0 1 1 1 0 0 1 0 1 0 1 0 0 1 1 1;
           7 1 6 0 5 2 1 6 0 0 0 0 1 1 1 0 1 1 1 0 0 0 1 0 1 0 1 0 0 1 1 1;
           1 7 0 6 6 1 2 5 0 0 0 0 1 1 1 0 1 1 1 0 0 0 1 0 1 0 1 0 0 1 1 1;
           3 5 2 4 2 5 6 1 0 0 1 0 1 0 1 0 0 1 1 1 0 0 1 0 1 0 1 0 0 1 1 1;
           4 2 5 3 7 0 3 4 0 0 1 0 1 0 1 0 0 1 1 1 0 0 0 0 1 1 1 0 1 1 1 0;
           6 0 7 1 3 4 7 0 0 0 0 0 1 1 1 0 1 1 1 0 0 0 0 0 1 1 1 0 1 1 1 0];
%matlab的下标从1开始,因此将前8列的状态值加1
state_map(:,1:8)=state_map(:,1:8)+1;
%将后24列的输出值转换成+1/-1形式
state_map(:,9:end)=state_map(:,9:end)*2-1;