convolutionalcode_phase1.m

卷积码（对数据流）编码解码,并分析结果。附带打孔程序段。

%%%%%%%%%   ECE 8001 Fall Error Correction Coding Project (Phase 1)    %%%%
%%%%%%%%%   Author: Xin Li # 14005390   %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%%%%%%%%%%   [e-mail]       %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%%%%%%%%   University of Missouri   %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

close all;
clear all;
clc;
sample_number = 25;
L = 512;
Smaple = randint(L,sample_number,[0,1]);
CW = 2*ones(L,2,sample_number);
EvaluateResult = inf*ones(10,10,25); % dim1 error ratio,
%dim2 error patterns, dim3 smaple,


% trellis = poly2trellis(5,[23,35]);
%%%%%%Step1:Encoder design
g1 = [1, 0, 0, 1, 1, 0];
g2 = [1, 1, 1, 0, 1, 0];

%%%%%%Step2: Building the trellis
for i = 0:31
    Table.CurState(i+1,:) = bitget(i, 5:-1:1);
end

Table.CurState(33:64,:) = Table.CurState(1:32,:);

Table.Input(1:32,:) = 1;
Table.Input(33:64,:) = 0;

for i = 1:64
    Tot_b(i,:) = [Table.Input(i,:) Table.CurState(i,:)];
    Table.NextState(i,:) = [Table.Input(i,:) Table.CurState(i,1:4)];
end

for i = 1:64
    c1_temp(i,:) = bitand(Tot_b(i,:),g1);
    c2_temp(i,:) = bitand(Tot_b(i,:),g2);
end

c1 = mod(sum(c1_temp,2),2);
c2 = mod(sum(c2_temp,2),2);
Table.Output = [c1 c2];

Table.CurSNum = bin2dec(num2str(Table.CurState));
Table.NextSNum = bin2dec(num2str(Table.NextState));

for s_i = 1:sample_number
    %%Encoding%%%

    % a = 0;
    % b = 1;
    % m = floor((b-a+1)*rand(L,1)) +a;

    m = Smaple(:,s_i);

    Cur_State = 0;
    for i = 1:L
        index = find(Table.Input==m(i) & Table.CurSNum==Cur_State);
        Cur_State = Table.NextSNum(index);
        OutputCW(i,:) = Table.Output(index,:);
    end
    CW(:,:,s_i)= OutputCW;
    %Step3: Impletmentthe Viterbi decoding algorithm to OutputCW

    for p_error = 1:10
        for error_pattern = 1:10

            Receive = CW(:,:,s_i);         %1.Input receiving sequence
            % Receive = randint(L,2,[0 1]);

            %%%%%%%%%%%%%%%%%Puncturing Part%%%%%%%%%%%%%%%
            %             %             punc_position = [4:4:L];    %3/4
            %             punc_position = [5:5:L];    %4/5
            %             Receive(punc_position,:)=NaN;
            %             Receive_Temp = Receive;
            %             Receive_Temp(isnan(Receive_Temp)) = [];
            %             [R_s(1) R_s(2)] = size(Receive_Temp);
            %
            %             error_n = round(R_s(1)*R_s(2)*0.01*p_error);
            %             error_position = randperm(R_s(1)*R_s(2));
            %             error_position = error_position(1:error_n);
            %             new_error_position = error_position+2*fix(error_position/9);
            %             E_pattern = zeros(2,L);
            %             E_pattern(new_error_position) = 1;
            %             Receive = abs(Receive-E_pattern');

            %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%


            %%%%%%%%%%%%%%%%Unpuncturing Part%%%%%%%%%%%%%%%
            error_n = round(L*2*0.01*p_error);
            error_position = randperm(L*2);
            error_position = error_position(1:error_n);
            E_pattern = zeros(L,2);
            E_pattern(error_position) = 1;

            Receive = abs(CW(:,:,s_i)-E_pattern);

            %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%


            X = -1*ones(L,1);          %2.Output sequence
            M = inf*ones(32,L);
            M(1,1) =0;            %3.initial path cost

            P = -1*ones(32,L);
            P(:,1)=[1:32];      % 4.initial paths
            t = 1;          % 5.set t = 0

            while t<=L           %6. Begin

                for i = 1:32            %7.for each state q at time t+1
                    p_index = find(Table.NextSNum == i-1);
                    for j = 1:2
                        if isnan(Receive(t,1))||isnan(Receive(t,2))
                            Mut(j) = 0;
                            Mt(j) = M(Table.CurSNum(p_index(j))+1,t)+ Mut(j);
                        else
                            Mut(j) = sum(xor(Table.Output(p_index(j),:),...
                                Receive(t,:)),2);
                            %8.find the path metric for each path to state q
                            Mt(j) = M(Table.CurSNum(p_index(j))+1,t)+ Mut(j);
                            %9.for each pi connected to state q
                            %corresponding to input
                            %x(pi,q),cmput mt(q)=M(pi)+Mut(rt,x(pi,q)).
                        end
                    end
                    [C,I] = min(Mt);
                    M(i,t+1) = C;
                    %10.Select the smallest metrix M(q)=minimi and the
                    %corresponding predecessor state p.
                    P(i,t+1) = Table.CurSNum(p_index(I));
                    %         X(i,t) = Table.Input(p_index(I));
                    %11.Extend the path to state q: Path(q)=[Path(p) p]
                end             %12.end for
                t = t+1;            %13.t= t+1
            end             %14.if t<L-1, goto 6
            
            %15.Termination:
            [C1 I1] = min(M(:,L+1));
            for i = L+1:-1:2
                X(i-1) = Table.Input(find(Table.NextSNum==(I1-1) &...
                    Table.CurSNum==P(I1,i)));
                I1 = P(I1,i)+1;
            end   %16.Return the Sequence

            ErrorLeft = sum(xor(m,X));
            EvaluateResult(p_error,error_pattern,s_i) = ErrorLeft;
        end
    end
end

AvgDh = sum(sum(EvaluateResult,3),2)/250;