CRC-32 System for Transmission of Bit Streams

%This script generates the transmitted bit stream for a 64-bit input 
%It uses CRC-32 (IEEE 802.3) generator to generate 32-bit FCS
 
input_data = dec2bin(hex2dec('FEDCBA9876543210')); % convert input to binary string
 
input_data = input_data - '0';      %convert from binary to int
append_lwrend = zeros(1,32);        % generator polyn is of 32 bits
D_X = [input_data  append_lwrend];  %construct the D(X) by padding zeroes to the end for division
 
 
G_X= [ 1,0,0,0,0,0,1,0,0,1,1,0,0,0,0,0,1,0,0,0,1,1,1,0,1,1,0,1,1,0,1,1,1];  %CRC-32 vector
    
 
 
chunkOfD_X = D_X(1:length(G_X));
Result = xor(chunkOfD_X, G_X);  %xor for the first time.  
 
 
length_difference = length(D_X) - length(G_X);
 
i = 1;
for R=  1: length_difference
    
    if(i ~= length_difference)        %bringing down the next bit to append
  next_D_Xbit = D_X(33 + i);            %obtain the next bit in the data
  i=i+1;
    end;
 
Shifted_Result = horzcat(Result, next_D_Xbit );  %append the next bit in data to our sliding dividend
Shifted_Result = Shifted_Result(2:34);           %throwaway the leftmost bit
 
 
 
if ( Shifted_Result(1) ) == 0               %check whether the leading bit of the current 33-bits is 0 or 1
    
    Result = xor(Shifted_Result, zeros(1,33));
else 
    Result = xor(Shifted_Result, G_X);
end;
 
 
end;
Result = Result(2:33);      %throwaway the leftmost bit
 disp(['The remainder is ', num2str(Result)]); 
 
Tx_Frame = horzcat(input_data, Result); %concatenate the data and the remainder
disp(['The transmitted stream is ', num2str(Tx_Frame)]);