block_code_sim.m

Digital communication labs,

function [encoded,received,corrected,decoded]=block_code_sim(G,n,k,information_bits,to_flip)

len=length(information_bits); % finding the length of the info bits

number_blocks=len/k;            % finding the number of blocks of information bits 
                              % by dividing by info word length

j=0;

while j ~= number_blocks,    % encoding, decoding, correcting the block of bits 
    
    information_bits1= information_bits(1,(j*k)+1:(j+1)*k);  %taking the information_bits in sets
    
    [encoded(1,(j*n)+1:(j+1)*n)]= encode(G,n,information_bits1); % we have now received the info bits in blocks i.e. info_bits_1
                                                                       % we are now encoding them 
                                                                      
    [received(1,(j*n)+1:(j+1)*n)]=receive(encoded(1,(j*n)+1:(j+1)*n),n,k,j,to_flip);  % now we are getting the received bits
                                                                                      % from the encoded bits 
                                                                     
                                                                      
    [corrected(1,(j*n)+1:(j+1)*n)]=correct(G,n,k,received(1,(j*n)+1:(j+1)*n));  % correcting the bits from the received bits
    
    
    [decoded(1,(j*k)+1:(j+1)*k)]=decode(n,k,corrected(1,(j*n)+1:(j+1)*n));   % decdoding the block of bits received 
    
    j=j+1;
end


% NOW THE WHOLE PRINTING STUFF STARTS

fprintf('********************************************');
fprintf('********************************************');
fprintf('********************************************');

fprintf('\nTable with information bits -- code-word pairs:\n\n');

for i=0:2^k-1
    
    m=convert(i,k);
    
    code=encode(G,n,m);
    
    fprintf('[')
    
    for i=1:k
        fprintf('%d',m(1,i));
    end
    
    fprintf(']  ->  [');
    
    for i=1:n
        fprintf('%d',code(1,i))
    end
    
    fprintf(']');
    fprintf('\n');
end

fprintf('********************************************');
fprintf('********************************************');
fprintf('********************************************');

% NOW PRINTING THE S VECTORS AND TABLE ERROR BITS

fprintf('****************************************************');
fprintf('\nTable with bit errors -- syndrom pairs:\n\n');

p=G(1:k,1:n-k);    % PARITY MATRIX

h=[eye(n-k) p'];    % H MATRIX

trans_h= h';   % TRANSPOSED H MATRIX

for i=0:2^n-1
    
    biterrors=convert(i,n);
    
    syndrom=biterrors*trans_h;          % CALCULATING THR SYNDROME MATRIX BY MULTIPLYING BIT ERRORS WITH TRANSPOSE MATRIX
    
    for i=1:n-k,
        if rem(syndrom(1,i),2)==0,      % SYNDROM MATRIX 
            syndrom(1,i)=0;
        else syndrom(1,i)=1;
        end
    end
    
    fprintf('[')

    % PRINTING THE MATRICES   
    
    for i=1:n
        fprintf('%d',biterrors(1,i));   % PRINTING THE BIT ERRORS
    end
    
    fprintf(']  ->  [');
    for i=1:n-k
        fprintf('%d',syndrom(1,i))    % PRINTING THE SYNDROME MATRIX
    end
    
    fprintf(']');
    fprintf('\n');
end
fprintf('\n*********************************************');

% DISPLAYING THE INFORMATION BITS AND THE ENCODEDE BITS

fprintf('\n\ninformation bits to be encoded:\n\nBits >>>>>');    % DISPLAYING THE INFO BITS
disp(information_bits);

fprintf('\n*********************************************');
fprintf('\n\nMessage to be transmitted:\n\nencoded = \n');      % DISPLAYING THE ENCODED BITS
disp(encoded);

fprintf('\n*********************************************');

% DISPLAYING THE ENCODED MESSAGE WITH FLIPPED BITS

fprintf('\nThe following bits in the encoded message will be flipped >>>>> [ ')

len=length(to_flip);       % CALAULATING THE LENGTH OF FLIP BITS

for i=1:len,
    fprintf('%d',to_flip(i));
    fprintf(' ');
end

% DISPLAYING THE RECEIVED MESSAGE WITH ERRORS

fprintf('] \n Received message with errors:\nreceived = \n');     % DISPLAY CODE OF RCVD MSG WITH ERRORS
disp(received);

fprintf('\n*********************************************');
fprintf('\n*********************************************');
fprintf('\n*********************************************\n\n');

fprintf('corrected bits\n\n');    % DISPLAYING THE CORRECTED BITS
disp(corrected);

fprintf('\n Decoded bits\n\n');   % DISPLAYING THE DECODED BITS
disp(decoded);