【正文】 H(j, c1(cc)) = 0。 end else for cc = 1:lc 1 H(i, c1(cc)) = 0。 end end % if end % if end % for j end % for i end % iffprintf(39。LDPC matrix is created.\n39。)。function [c, newH] = makeParityChk(dSource, H, strategy)% Generate parity check vector bases on LDPC matrix H using sparse LU deposition%% dSource : Binary source (0/1)% H : LDPC matrix% strategy: Strategy for finding the next nonzero diagonal elements% {0} First : First nonzero found by column search27% {1} Mincol : Minimum number of nonzeros in later columns% {2} Minprod: Minimum product of:% Number of nonzeros its column minus 1% Number of nonzeros its row minus 1% % c : Check bits %%% Copyright Bagawan S. Nugroho, 2022 % % Get the matric dimension[M, N] = size(H)。% Set a new matrix F for LU depositionF = H。% LU matricesL = zeros(M, N M)。U = zeros(M, N M)。% Reorder the M x (N M) submatrixfor i = 1:M % strategy {0 = First。 1 = Mincol。 2 = Minprod} switch strategy % Create diagonally structured matrix using 39。First39。 strategy case {0} % Find nonzero elements (1s) for the diagonal [r, c] = find(F(:, i:end))。 % Find nonzero diagonal element candidates rowIndex = find(r == i)。 % Find the first nonzero column chosenCol = c(rowIndex(1)) + (i 1)。 % Create diagonally structured matrix using 39。Mincol39。 strategy case {1} % Find nonzero elements (1s) for the diagonal [r, c] = find(F(:, i:end))。 colWeight = sum(F(:, i:end), 1)。 % Find nonzero diagonal element candidates rowIndex = find(r == i)。 % Find the minimum column weight [x, ix] = min(colWeight(c(rowIndex)))。 % Add offset to the chosen row index to match the dimension of the... % original matrix F chosenCol = c(rowIndex(ix)) + (i 1)。 % Create diagonally structured matrix using 39。Minprod39。 strategy case {2} % Find nonzero elements (1s) for the diagonal28 [r, c] = find(F(:, i:end))。 colWeight = sum(F(:, i:end), 1) 1。 rowWeight = sum(F(i, :), 2) 1。 % Find nonzero diagonal element candidates rowIndex = find(r == i)。 % Find the minimum product [x, ix] = min(colWeight(c(rowIndex))*rowWeight)。 % Add offset to the chosen row index to match the dimension of the... % original matrix F chosenCol = c(rowIndex(ix)) + (i 1)。 otherwise fprintf(39。Please select columns reordering strategy!\n39。)。 end % switch % Reordering columns of both H and F tmp1 = F(:, i)。 tmp2 = H(:, i)。 F(:, i) = F(:, chosenCol)。 H(:, i) = H(:, chosenCol)。 F(:, chosenCol) = tmp1。 H(:, chosenCol) = tmp2。 % Fill the LU matrices column by column L(i:end, i) = F(i:end, i)。 U(1:i, i) = F(1:i, i)。 % There will be no rows operation at the last row if i M % Find the later rows with nonzero elements in column i [r2, c2] = find(F((i + 1):end, i))。 % Add current row to the later rows which have a 1 in column i F((i + r2), :) = mod(F((i + r2), :) + repmat(F(i, :), length(r2), 1), 2)。 end % if end % for i% Find z = mod(H(:, (N M) + 1:end)*dSource, 2)。% Parity check vector found by solving sparse LUc = mod(U\(L\z), 2)。 % Return the rearrange H newH = H。fprintf(39。Message encoded.\n39。)。function vHat = decodeBitFlipping(rx, H, iteration)% Harddecision/bit flipping sum product algorithm LDPC decoder%29% rx : Received signal vector (column vector)% H : LDPC matrix% iteration : Number of iteration%% vHat : Decoded vector (0/1) %%% Copyright Bagawan S. Nugroho, 2022 % [M N] = size(H)。% Prior harddecisionci = *(sign(rx39。) + 1)。% Initializationrji = zeros(M, N)。% Asscociate the ci matrix with nonzero elements of Hqij = H.*repmat(ci, M, 1)。 % Iterationfor n = 1:iteration fprintf(39。Iteration : %d\n39。, n)。 % Horizontal step for i = 1:M % Find nonzeros in the column c1 = find(H(i, :))。 % Get the summation of qij\c1(k) for k = 1:length(c1) rji(i, c1(k)) = mod(sum(qij(i, c1)) + qij(i, c1(k)), 2)。 end % for k end % for i % Vertical step for j = 1:N % Find nonzero in the row r1 = find(H(:, j))。 % Number of 1s in a row numOfOnes = length(find(rji(r1, j)))。 for k = 1:length(r1) % Update qij, set 39。139。 for majority of 1s else 39。039。, excluding r1(k) if numOfOnes + ci(j) = length(r1) numOfOnes + rji(r1(k), j) qij(r1(k), j) = 1。 else qij(r1(k), j) = 0。30 end end % for k % Bit decoding if numOfOnes + ci(j) = length(r1) numOfOnes vHat(j) = 1。 else vHat(j) = 0。 end end % for j end % for nfunction vHat = decodeProbDomain(rx, H, N0, iteration)% Probabilitydomain sum product algorithm LDPC decoder%% rx : Received signal vector (column vector)% H : LDPC matrix% N0 : Noise variance% iteration : Number of iteration%% vHat