33 results about "Bidiagonal matrix" patented technology

Disclosed is a method for puncturing a Low Density Parity Check (LDPC) code that is expressed by a factor graph having a check node and a variable node, connected to each other by an edge, and is decoded by a parity check matrix including a parity part having a single weight-3 column and a dual-diagonal matrix. The method includes selecting 1-step recoverable (1-SR) variable nodes with the highest quality including a variable node mapped to a weight-3 column, and setting a first puncturing priority group using the selected 1-SR variable nodes, selecting k-step recoverable (k-SR) variable nodes with the highest quality in the next step k taking into account the variable nodes selected in the current step, and setting a priority group for each individual step, puncturing an LDPC code mapped to a variable node belonging to a corresponding group according to priority of each group obtained in the preceding steps.

An apparatus and method for encoding low-density parity check (LDPC) codes. The method for generating a low-density parity check code formed of an information-part matrix and a parity-part matrix comprises the steps of converting the information-part matrix into an array code structure and assigning a degree sequence to each submatrix column; extending a dual-diagonal matrix corresponding to the parity-part matrix such that an offset value between diagonals has a random value; lifting the normalized dual-diagonal matrix; determining an offset value for cyclic column shift for each submatrix of the lifted normalized dual-diagonal matrix; and determining a parity symbol corresponding to a column of the parity-part matrix.

Algebraic method to construct LDPC (Low Density Parity Check) codes with parity check matrix having CSI (Cyclic Shifted Identity) sub-matrices. A novel approach is presented by which identity sub-matrices undergo cyclic shifting, thereby generating CSI sub-matrices that are arranged forming a parity check matrix of an LDPC code. The parity check matrix of the LDPC code may correspond to a regular LDPC code, or the parity check matrix of the LDPC code may undergo further modification to transform it to that of an irregular LDPC code. The parity check matrix of the LDPC code may be partitioned into 2 sub-matrices such that one of these 2 sub-matrices is transformed to be a block dual diagonal matrix; the other of these 2 sub-matrices may be modified using a variety of means, including the density evolution approach, to ensure the desired bit and check degrees of the irregular LDPC code.

A method of and an apparatus for generating a block-based low density parity check (LDPC) matrix, where calculation of an inverse matrix is not necessary and back-substitution is possible over the entire matrix area, and a recording medium having recorded thereon code for implementing the method. An area of the LDPC matrix is vertically divided based on respective lengths of first and second parity bit vectors and, a block-based matrix is generated such that a double diagonal matrix is arranged in an upper portion of an area corresponding to the second parity bit vector among areas into which the LDPC matrix is vertically divided., The area of the LDPC matrix is horizontally divided based on a position of the double diagonal matrix, and block-based matrices are generated in the divided areas of the LDPC matrix, to satisfy a condition that column weights (Wc) are uniform.

An apparatus and method for coding an irregular Repeat Accumulate (RA) code. A repeater repeats a received information word such that the information word corresponds to weights of a first information part and a second information part of a parity check matrix in which permutation matrixes are arranged in the first information part and the second information part corresponding to the information word such that a minimum length of a cycle on a factor graph of the irregular RA code becomes a predetermined length and weights are irregular, and a dual diagonal matrix is arranged in a parity part corresponding to a parity. An interleaver interleaves a signal output from the repeater using an interleaving scheme predefined for the parity check matrix. An accumulator generates the irregular RA code by accumulating a signal output from the interleaver according to a weight of the parity part.

A method is provided for puncturing a low density parity check (LDPC) code decoded by a parity check matrix that is expressed by a factor graph including a check node and a bit node, being connected to each other at an edge, and includes a parity part having a dual diagonal matrix with a single 3-weight column and the remaining columns being 2-weight columns. The method includes generating a puncturing pattern such that bits of the LDPC code are punctured in an order of a bit mapped to a column with a higher weight from among the columns constituting the parity part; and puncturing the LDPC code according to the generated puncturing pattern.

A method, a device, and an apparatus for correcting bursts are disclosed. The method includes: calculating a correction vector according to a received codeword and a check matrix, wherein the check matrix is an Overlapped Quasi Dual Diagonal Matrix; determining a length and position of a burst according to a longest zero element vector between two nonzero elements in the correction vector when the correction vector is nonzero; and calculating out an error mode according to the correction vector and the length of the burst, obtaining an error mode polynomial according to the error mode, correcting the received codeword according to the error mode polynomial, and obtaining a corrected codeword polynomial. The PBC-based implementation method for cyclic codes herein can correct more burst errors than the conventional cyclic code decoding method.

The invention discloses a method for generating LDPC codes. The method comprises the following steps that: step one, the size of a check matrix of the LDPC codes is set, wherein the check matrix is divided into an information portion and a check portion, wherein the check portion is obtained through dual diagonal matrix interweaving; step two, the information portion is divided into a plurality of sub information matrixes, wherein each sub information matrix comprise a plurality of circulatory arrays, and the column degree of each sub information matrix is determined, wherein the column degree is the number of non-zero circulatory arrays contained in the sub information matrix; step three, the positions of the non-zero circulatory arrays of each sub information matrix are determined; and step four, the offset of the non-zero circulatory arrays of each sub information matrix is determined. According to the method of the invention, on the one hand, the minimum distance of the codes is decreased through adopting an interweaving method, and on the other hand, optimal degree distribution and optimal circulatory matrix distribution can be researched by means of tools.

The invention discloses an encoding method of low bit-rate LDPC (Low Density Parity Check) code, including the following steps: (1) matrixes Hand H<d> are respectively constructed, the Hmatrix is a diagonal matrix, H<d> is an array matrix with q multiplied by 1 and is formed by q end-around-shift permutation matrixes Q; the permutation matrix Q is composed of b multiplied by b step permutation matrixes Q having row weight and line weight of 1, at most one element of 1 on each diagonal line and the rest elements of 0; (2) an H matrix with the size of equal to bq multiplied b(q+1) is constructed; (3) a check vector cis constructed, cis equal to (pl, 1=1, 2, ..., M)<T>, wherein p1 represents the value of any first check bit, and M is the length of check bit; (4) according to the check vector c=(p1), the inputted information vector c<d> is equal to (dj), and coded code word c=(c<d>c) is obtained. In the method of the invention, an algebraic method used by end-around-shift value of Q permutation matrix leads belief propagation iterative decoding algorithm to be more easily realized in parallel; bidiagonal matrix structural characteristic of Hmatrix can make the low rate LDPC code be encoded in a recursion manner, and have linear time computing complexity. The simulation performance is superior to the performance of the existing low rate error correcting code, thereby being capable of reaching a signal noise ratio of 0.4 dB and having ratio compatibility.

The invention discloses a method for generating an LDPC (Low Density Parity Check) code check matrix and an LDPC code coding method based on the LDPC code check matrix. The method for generating the LDPC code check matrix comprises the following steps of firstly establishing an index matrix, then establishing a check matrix by the indexing matrix, and specifically, generating the check matrix after expanding each number axy in the index matrix A into a q order (0, 1) matrix; and enabling elements in the positions (i, iaxy (modq+1)) to be 1, enabling elements in other positions to be 0, wherein i = 1, 2, 3 ellipsis q. In addition, the check matrix being a combination of a matrix which is generated by adopting the method and a double-diagonal matrix is provided. The invention also provides the LDPC code coding method by adopting the check matrix generated by any optional method. The method for generating the LDPC code check matrix and the LDPC code coding method have the advantages of easiness in design, low coding complexity, small storage space and excellent performance.

The present application provides an LDPC encoding method and a device for a communication signal, for reducing encoding complexity. The encoding method comprises: acquiring an (N-M) × 1 information bit vector I(x) according to information bits of a communication signal to be sent; acquiring a check set vector D(x) according to I(x) and an M × (N-M) system partial matrix N(x), where D(x) meets the following condition: D(x) = {N(x) I(x)} mod 2; determining an M × M check partial matrix M(x), wherein M(x) is a bidiagonal matrix, a polynomial matrix Q(x) corresponding to a first column vector of M(x) is represented as Q(x) = I + x ah + x bh , Q -1 (x) = x -2×β×h Q(x), a and b are different constants, h = 2 j-1 , and β and j are positive integers; determining, according to D(x) and M(x), a check bit vector C(x) corresponding to I(x), where C(x) meets the following condition: D(x) = {M(x) C(x)} mod 2; and generating, according to I(x) and C(x), a code word corresponding to the communication signal to be sent.