viterbi_decoder_acs217.m

2,1,7卷积码译码s-function

function [sys,x0,str,ts] = viterbi_decoder_acs217(t,x,u,flag)

switch flag,
  case 0,
    [sys, x0, str, ts] = mdlInitializeSizes(t, x, u);
  case 2,                                                
    sys = mdlUpdate(t,x,u); 
  case 3,                                                
    sys = mdlOutputs(t,x,u);
  case 9,                                                
    sys = []; 
  otherwise
    error(['unhandled flag = ', num2str(flag)]);
end

%end dsfunc

%
%=======================================================================
% mdlInitializeSizes
% Return the sizes, initial conditions, and sample times for the S-function.
%=======================================================================
%
function [sys, x0, str, ts] = mdlInitializeSizes(t, x, u)

sizes = simsizes;
sizes.NumContStates  = 0;
sizes.NumDiscStates  = 6852;    %6628+132;
sizes.NumOutputs     = 1;
sizes.NumInputs      = 4;
sizes.DirFeedthrough = 1;
sizes.NumSampleTimes = 1;

sys = simsizes(sizes);

x0  = zeros(1,sizes.NumDiscStates);
str = [];
ts  = [-1.0 0.0]; 

% end mdlInitializeSizes

%
%=======================================================================
% mdlUpdate
% Handle discrete state updates, sample time hits, and major time step
% requirements.
%=======================================================================
%
function sys = mdlUpdate(t, x, u)

%%%%%%initialize%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
met_in = u;
% for i1 = 1 : 132
%     met_in_D(i1) = x(6700+i1);
% end
met_in_D(1:132) = x(6721:6852);
met_in_D(133:136) = met_in;

    


met_ac = x(1:64);
rout = zeros(3,64,35);
% for i1 = 1 : 6528             %% 3*64*34 = 6528
%     rout(i1) = x(100+i1);
% end
rout(1:6528) = x(101:6628);
if rout == 0
    rout(1,1,1:33) = 1;
    rout(2,1,1:33) = 1;
    rout(3,1,1:33) = 0;
    rout(:,1,34) = [1 1 2]';
% rout(:,1,33) = [1 0 2]';
% rout(:,1,34) = [0 0 0]';
% rout(:,2,34) = [2 3 4]';

    met_ac = zeros(64,1);
end

trellis217 = trellis217_fcn;

met_ac_tmp1 = zeros(64,1);
met_ac_tmp2 = zeros(64,1);
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

for i1 = 1 : 64
    if rout(1,i1,34) ~= 0
        ns_1 = trellis217(i1,[3 4]) + [1 1];
        ns = [rout([2 3],i1,34)]';        
        met_index = trellis217(i1,[1 2])+[1 1];
        met_ac_tmp2(ns_1(1)) = met_in(met_index(1)) + met_ac(i1);
        met_ac_tmp2(ns_1(2)) = met_in(met_index(2)) + met_ac(i1);
        for i2 = 1 : 2
            if ns(i2) == 0
                break;
            else
            if rout(1,ns(i2),35) == 0
                met_ac_tmp1(ns(i2)) = met_ac_tmp2(ns(i2));
                rout(1,ns(i2),35) = i1;
                rout([2 3],ns(i2),35) = [trellis217(ns(i2),[3 4])+[1 1]]';
            elseif met_ac_tmp2(ns(i2)) < met_ac_tmp1(ns(i2))
                met_ac_tmp1(ns(i2)) = met_ac_tmp2(ns(i2));
                ns_now = ns(i2);
                index_del = rout(1,ns_now,35);
                rout(1,ns(i2),35) = i1;
                rout([2 3],ns(i2),35) = [trellis217(ns(i2),[3 4])+[1 1]]';
                ns_set = trellis217(index_del,[3 4]) + [1 1];
                j1 = 34;               
                while 1,
                    switch ns_now,
                        case ns_set(1),
                            rout(2,index_del,j1) = 0;
                        case ns_set(2),
                            rout(3,index_del,j1) = 0;
                        otherwise
                            error('error index');
                    end
                    if rout(2:3,index_del,j1)==[0;0]
                        ns_now = index_del;
                        index_del = rout(1,ns_now,j1);
                        rout(1,ns_now,j1) = 0;
                        ns_set = trellis217(index_del,[3 4]) + [1 1];
                        j1 = j1-1;
                        if j1 == 1
                            break;
                        end
                    else
                        break;
                    end
                end
            else
                ns_now = ns(i2);
                index_del = i1;
                ns_set = trellis217(index_del,[3 4]) + [1 1];
                j1 = 34;
                while 1,
                    switch ns_now,
                        case ns_set(1),
                            rout(2,index_del,j1) = 0;
                        case ns_set(2),
                            rout(3,index_del,j1) = 0;
                        otherwise
                            error('error index');
                    end
                    if rout(2:3,index_del,j1)==[0;0]
                        ns_now = index_del;
                        index_del = rout(1,ns_now,j1);
                        rout(1,ns_now,j1) = 0;
                        ns_set = trellis217(index_del,[3 4]) + [1 1];
                        j1 = j1-1;
                        if j1 == 1
                            break;
                        end
                    else
                        break;
                    end
                end                
            end    
            end
        end
    end
end

met_ac = met_ac_tmp1;
met_ac_35 = met_ac;
num = 0;

for i1 = 1 : 64
    if rout(1,i1,2) ~= 0
        num = num + 1;       
        codeword_tmp = mod(i1+1,2);
        node_head = rout(1,i1,2);
    end
end

if num == 1
    codeword = codeword_tmp;
    met_ac_35 = met_ac_35 - min(met_ac_35);
%     met_ac_35 = met_ac_35 - met_in_D(trellis217(node_head,codeword+1)+1);            %%%%    ????????????????
%     met_ac_35 = met_ac_35 - met_in_D(bin_vector_to_dec(trellis217(node_head,codeword+1))+1);            %%%%    ????????????????    
else
%     codeword = 0;
    codeword = 0;
    met_ac_35 = met_ac_35 - min(met_ac_35);
    %     codeword = 2;
    rout(3,node_head,1) = 0;
    for ia = 2 : 35
        for ib = 1 : 64
            if rout(1,ib,ia) ~= 0
                ps = rout(1,ib,ia);
                ps_set = rout([2 3],ps,ia-1);
                if ps_set(1) ~= ib & ps_set(2) ~= ib
                    rout(:,ib,ia) = zeros(3,1);
                end
            end
        end
    end
end



x_reg(100) = codeword;
% for i1 = 1 : 6528
%     x_reg(100+i1) = rout(192+i1);
% end
x_reg(101:6628) = rout(193:6720);
x_reg(1:64) = met_ac_35;

% for i1 = 1 : 132
%     x_reg(6700+i1) = met_in_D(4+i1);
% end
x_reg(6721:6852) = met_in_D(5:136);
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

sys = x_reg;


%end mdlUpdate

%
%=======================================================================
% mdlOutputs
% Return the output vector for the S-function
%=======================================================================
%
function sys = mdlOutputs(t, x, u)

sys = x(100);

%end mdlOutputs