.[.A method for constructing a low-density parity-check (LDPC) code using a structured base parity check matrix with permutation matrix, pseudo-permutation matrix, or zero matrix as constituent sub-matrices; and expanding the structured base parity check matrix into an expanded parity check matrix. A method for constructing a LDPC code using a structured base parity check matrix H=[H.sub.d|H.sub.p], H.sub.d is the data portion, and H.sub.p is the parity portion of the parity check matrix; the parity portion of the structured base parity check matrix is such so that when expanded, an inverse of the parity portion of the expanded parity check matrix is sparse; and expanding the structured base parity check matrix into an expanded parity check matrix. A method for encoding variable sized data by using the expanded LDPC code; and applying shortening, puncturing..]. .Iadd.System and method for operating a wireless device to encode data using low-density parity-check (LDPC) encoding is discussed. One example method includes: computing a number of modulated orthogonal frequency-division multiplexing (OFDM) symbols for transmitting the data; computing a number of shortening bits; distributing the number of shortening bits over the at least one LDPC codeword; computing a number of puncturing bits for the at least one LDPC codeword; distributing the number of puncturing bits over the at least one LDPC codeword; determining a criterion using at least one of the number of shortening bits and the number of puncturing bits; if the criterion is met, increasing the number of modulated OFDM symbols and recalculating the number of puncturing bits; generating the encoded data using the number of shortening bits, the number of puncturing bits, and the at least one LDPC codeword; and transmitting the encoded data..Iaddend.

Disclosed relates to a decoder for LDPC code, including: a variable node processing unit; a check node processing unit; a memory for storing iterative messages of edges of a parity-check matrix for LDPC code; and a controller for controlling the node processing units to perform iterations of decoding until the decoding ends, wherein, in each iteration of decoding, the controller controls the variable node processing unit to compute variable node messages in a traversing manner for all variable nodes and updates the iterative messages in the memory according to the computed variable node messages, and controls the check node processing unit to compute check node messages in a traversing manner for all check nodes and updates the iterative messages in the memory according to the computed check node messages.

A method by which a terminal performs rate matching for a low density parity check (LDPC) code can comprise the steps of: determining any one transport block size (TBS) among a plurality of TBSs set for rate matching in the terminal; and performing rate matching for the LDPC code on the basis of the selected TBS. The UE is capable of communicating with at least one of another UE, a UE related to an autonomous driving vehicle, a base station or a network.

An improved layered decoding method for a low density parity check (LDPC) code and a device therefor are disclosed. Disclosed is the layered decoding method for an LDPC code, capable of determining whether decoding is successful by performing a syndrome check on each check node at every variable node update. In addition, the syndrome check can be performed by using reduced variable nodes, thereby reducing decoding power consumption and decoding time consumption.

A pre-5th-generation (pre-5G) or 5G communication system for supporting higher data rates beyond a 4th-generation (4G) communication system, such as long term evolution (LTE) is provided. A channel encoding method in a communication or broadcasting system includes identifying an input bit size, determining a block size (Z), determining a low density parity check (LDPC) sequence to perform LDPC encoding, and performing the LDPC encoding based on the LDPC sequence and the block size.

This application discloses a method and an apparatus for processing information, a communications device, and a communications system. The communications device is configured to obtain a starting position of an output bit sequence in a coded block in a circular buffer, and determine the output bit sequence in the coded block based on a length of the output bit sequence and the starting position. A value of the starting position is one of {p.sub.0, p.sub.1, p.sub.2, . . . , p.sub.k.sub.max .sub.−1}, where 0≤p.sub.k <N.sub.CB, p.sub.k is an integer, k is an integer, 0≤k<k.sub.max , N .sub.CB is a size of the coded block, and k.sub.max is an integer greater than or equal to 4.

This application discloses a method and an apparatus for processing information, a communications device, and a communications system. The communications device is configured to obtain a starting position of an output bit sequence in a coded block in a circular buffer, and determine the output bit sequence in the coded block based on a length of the output bit sequence and the starting position. A value of the starting position is one of {p.sub.0, p.sub.1, p.sub.2, . . . , p.sub.k.sub.max.sub.−1}, where 0≤p.sub.k<N.sub.CB, p.sub.k is an integer, k is an integer, 0≤k<k.sub.max, N.sub.CB is a size of the coded block, and k.sub.max is an integer greater than or equal to 4.

Provided is an encoding method and device and a decoding method and device for structured LDPC. The encoding method includes: determining a base matrix used for encoding and performing an LDPC encoding operation on a source information bit sequence according to the base matrix and an expansion factor Z corresponding to the base matrix to obtain a codeword sequence, where Z is a positive integer. The base matrix includes multiple submatrices and the submatrices include an upper-left submatrix Hb1 and an upper-left submatrix Hb2, and the upper-left submatrix Hb1 is an upper-left submatrix of the upper-left submatrix Hb2.

A pre-5th-generation (pre-5G) or 5G communication system for supporting higher data rates beyond a 4th-generation (4G) communication system, such as long term evolution (LTE) is provided. A channel encoding method in a communication or broadcasting system includes identifying an input bit size, determining a block size (Z), determining a low density parity check (LDPC) sequence to perform LDPC encoding, and performing the LDPC encoding based on the LDPC sequence and the block size.

Protograph-based LDPC codes are obtained from z-row-orthogonal base matrices with some additional structure constraints, such as a diagonal and/or double-diagonal structure, in order to allow a high parallelization that is a multiple of z, while having an efficient encoding or decoding. A “big” base matrix is constructed from a structured square submatrix in order to have a WiMAX-like structure and a z-row-orthogonality. Also, starting from a “smaller” base matrix having a part arranged in a double-diagonal shape with tail-biting one, an expansion by a factor equal to z can be performed, followed by an addition of a single one-entry into the last column at a specific location, thereby obtaining a three-degree column, and followed by a row and/or column permutation in order to obtain a base matrix in a WiMAX-like structure.