paritycheckmatrixh.m

LDPC codes .Using the matlab.

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function checkMatrix_H = ParityCheckMatrixH()
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% @author	Andreas Waadt, 13. November 2005
% @param     
% @return   checkMatrix_H : 7 x 7 LDPC check-sum-matrix
% This function generates a 7 x 7 Parity-Check-Matrix H for LDPC-Codes.
% The Matrix is cyclic and from rank 4 (binary).
% The LDPC-Code, represented by the null-space of H has dimension 3.
% Its girth is 6. The number of ones per row (roh) an the number of ones
% per column (gamma) are 3.
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        % number of rows
		j_rows = 7;
		% number of columns
		n_columns = 7;
		% parity check matrix
		checkMatrix_H = zeros(j_rows,n_columns);
		
		% initialize the parity check matrix
		checkMatrix_H(1,1) = 1;
		checkMatrix_H(1,2) = 1;
		checkMatrix_H(1,3) = 0;
		checkMatrix_H(1,4) = 1;
		checkMatrix_H(1,5) = 0;
		checkMatrix_H(1,6) = 0;
		checkMatrix_H(1,7) = 0;
		
		% cyclic code continuation
		index_n = 0;
		for cnt_j = 2 : 1 : j_rows
			checkMatrix_H(cnt_j,1) = checkMatrix_H(cnt_j-1,7);
			for cnt_n = 2 : 1 : n_columns
				checkMatrix_H(cnt_j,cnt_n) = checkMatrix_H(cnt_j-1,cnt_n-1);
            end;
        end;
        
        %checkMatrix_H
        
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