Abstract:
Encoder and decoder devices for performing multi-rate and multi-length LDPC coding and decoding and methods thereof using only one stored expansion table with one corresponding expansion factor. An encoder device (200) for performing LDPC coding includes: an input (210) for receiving an information sequence (B1); an output (220) for providing an encoded sequence (B2); a memory (201) for storing exponent matrices (H exp ), wherein the exponent matrices (H exp ) are stored in a plurality of groups (203a, 203b, 203c), such that each group (203a, 203b, 203c) corresponds to one code rate, and wherein each group (203a, 203b, 203c) comprises a plurality of nested exponent matrices (H exp ), each nested exponent matrix (H exp ) within a particular group corresponding to one code word length for the code rate of the particular group, wherein common elements in different groups (203a, 203b, 203c) are stored once in the memory (201); and further comprising a processing unit (205) configured to extract an exponent matrix (H exp ) for a specific code rate (R) from a corresponding group (203a, 203b, 203c) and; an encoding unit (207) for encoding the information sequence (B1) based on the extracted parity-check exponent matrix (H exp ) to provide the encoded sequence (B2).
Abstract:
A channel coding method in a communication system using a Low-Density Parity-Check (LDPC) code. The channel coding method includes determining a degree distribution for a plurality of column groups of an information part and a plurality of column groups of a parity part; determining degrees for the plurality of column groups of the information part based on the degree distribution; determining a shortening order based on the degrees for the plurality of column groups of the information part; generating a parity check matrix based on the shortening order; and performing coding using the generated parity check matrix.
Abstract:
A method and apparatus are provided for generating a parity check matrix used to generate a linear block code in a communication system. The method includes determining a basic parameter of a second parity check matrix satisfying a rule predetermined with respect to a given first parity check matrix, generating a submatrix corresponding to a parity part of the second parity check matrix, using the basic parameter; and generating a submatrix corresponding to an information word part of the second parity check matrix, using the first parity check matrix and the basic parameter.
Abstract:
k input bits are encoded according to a code with which is associated a m x n=m+k parity check matrix H. The resulting codeword is punctured, with n' bits. The punctured codeword is exported to a corrupting medium such as a communication channel or a memory. A representation of the punctured codeword is imported from the corrupting medium and is decoded using a matrix H' that is smaller than H. For example, H' is m'=m~(n-n ') x n' and is derived by merging selected rows of H. Alternatively, H has at most m rows and fewer than n columns but more than n' columns. Alternatively, H has fewer than m'=m-(n-n') rows and fewer than n' columns.
Abstract:
An encoding/decoding apparatus and method using a low-density parity-check code (LDPC code) is disclosed. Basic column group information, serving as a set of information regarding positions of rows with weight 1, is extracted from a reference column in each column group of a predetermined parity-check matrix. Column group information transforms the positions of rows with weight 1 into positions whose lengths are within a required parity length. A parity-check matrix is generated according to the generated column group information. Data is encoded or decoded based on the generated parity-check matrix.
Abstract:
For correcting a multibit, LDPC coded codeword where one or two multibit symbols within the codeword are known to be erroneous, a method is proposed, where the position of the erroneous multibit symbols is checked for correctability, where the subset of the codeword that is not indicated as erroneous is GF2- multiplied with a corresponding subset of the parity check matrix of the LDPC code resulting in an interim vector, and where the erroneous parts of the codeword are reconstructed such that they, when GF2-multiplied to their associated parts of the parity check matrix, yield the same interim vector.
Abstract:
An apparatus and method for generating a parity-check matrix of a Low-Density Parity-Check (LDPC) code are provided. Parameters for designing the LDPC code are determined, and a first parity-check matrix of a quasi-cyclic LDPC code is formed according to the determined parameters. A second parity-check matrix is created through the elimination of a predetermined portion of a parity part in the first parity-check matrix, and a third parity-check matrix is created by rearranging the second parity-check matrix.
Abstract:
An LOPC decoder suitable (or a range of codeblock sizes and bit-rates, which is also suitable for both ASIC and FPGA implementations, are provided The LOPC decoder can be optimized for either elRA based H matrices or for general H matrices, as may be desirable An H parity matrix can be constructed and/or manipulated to arrange the bit-node message "columns" to facilitate mapping to MPB "columns" and corresponding access via LUT pointer tables to minimize processing cycles.