isi_table.m

用Matlab仿真turbocode的算法

function [state_table,output_table,ST]=isi_table(g)
%to build the output%state tables of inner encoder
%g=[1 1 0 0;4 3 2 1];


[plynum,plylen]=size(g);
m = plylen-1;
state=ones(1,m);
new_state=state;
input=[+1 -1];
state_table=zeros(2^length(state),2^(plynum-1));
output_table=state_table;
ST=zeros(4,2^(plynum-1)*2^length(state));

for state_skalar=1:2^length(state)					
   
    state=bin_state(state_skalar-1,length(state),'bipolar');	%'length(state)' means memory length		
        
       
        
        for x=0:2^(plynum-1)-1
             d_k=input(x+1);
             [dummy,dummy,v]=find(g(1,:).*[d_k state]);
             a_k=prod(v);    %input&feedback
             output_table(state_skalar,x+1)=g(2,:)*[a_k state]'; % output    
             
             new_state=[a_k state(1:m-1)];
             state_table(state_skalar,x+1)=int_state(new_state,'bipolar')+1;   %next state
            
        end
           
end

ST(1,:)=mod([0:size(ST,2)-1],2^(plynum-1))+1;
ST_output=output_table';
ST(2,:)=ST_output(1:end);
ST(3,:)=(floor([0:size(ST,2)-1]/(2^(plynum-1)))+1);
states=state_table';
ST(4,:)=states(1:end);