Certain aspects of the present disclosure provide an efficiently decodable QC-LDPC code which is based on a base matrix, the base matrix being formed by columns and rows, the columns being dividable into one or more columns corresponding to punctured variable nodes and columns corresponding to non-punctured variable nodes. Apparatus at a transmitting side includes a encoder configured to encode a sequence of information bits based on the base matrix. Apparatus at a receiving side configured to receive a codeword in accordance with a radio technology across a wireless channel. The apparatus at the receiving side includes a decoder configured to decode the codeword based on the base matrix.

Certain aspects of the present disclosure generally relate to techniques for puncturing of structured low-density parity-check (LDPC) codes. Certain aspects of the present disclosure generally relate to methods and apparatus for a high-performance, flexible, and compact LDPC code. Certain aspects can enable LDPC code designs to support large ranges of rates, blocklengths, and granularity, while being capable of fine incremental redundancy hybrid automatic repeat request (IR-HARQ) extension while maintaining good floor performance, a high-level of parallelism to deliver high throughout performance, and a low description complexity.

An encoding and decoding method of low-density parity-check code is disclosed. The method is following steps: a high rate check code is transferred to a check matrix having a protograph. The check matrix is extended to form an extended base matrix and is split to form a split base matrix. The extended base matrix and the split base matrix are respectively calculated to generate their decoding threshold by a protograph extrinsic information transfer chart. The base matrix with the lower decoding threshold is considered as a low rate base matrix. Repeating the above process until a stop condition is satisfied. The last low rate base matrix is expanded to form a parity check matrix. The transmission data is encoded and decoded by the parity check matrix.

A transmission device and reception device for digital data that have excellent resistance to noise are provided. An encoder (11-1) of this disclosure, included in a transmission device (1) of this disclosure, applies LDPC encoding to digital data using a unique check matrix for each code rate by using a check matrix in which, taking a check matrix initial value table established in advance for each code rate at a code length of 44880 bits as initial values, 1 entries of a partial matrix corresponding to an information length appropriate for a code rate of 93/120 are allocated in the column direction over a cycle of 374 columns. A demodulator (23) of this disclosure, included in a reception device (2) of this disclosure, decodes digital data encoded by the encoder (11-1).

Techniques are described for optimizing a parity-check matrix for a low density parity check (LDPC) encoder. In an example, a first parity-check matrix is accessed. Based on a set of rules, an independent set of check nodes and variable nodes is determined. The set of rules specifies that a check node associated with the first parity-check matrix belongs to the independent set when the check node is connected to only one variable node from the independent set. The set of rules further specifies that a variable node associated with the first parity-check matrix belongs to the independent set when the variable node is connected to only one check node from the independent set. A size of the independent set is based on the set of rules. A second parity-check matrix is generated by at least applying a permutation to the first parity-check matrix based on the independent set.

A method for defining an erasure code for system having a predetermined number of data disks is disclosed. The method includes selecting step, constructing step, determining step and repeating step. The selecting step includes selecting a predetermined acceptable number of failures for the system. The constructing step includes constructing a first Tanner graph for two failures acceptable system having predetermined number of data disks. The determining step includes determining erasure code from the first Tanner graph. The repeating step includes repeating the constructing step and the determining step by increasing the acceptable number of failures by one and constructing another Tanner graph in response to the increased acceptable number of failures by increasing number of parity nodes until the predetermined number of failures for the system is reached.

The present technology relates to a transmission method and a reception device for securing favorable communication quality in data transmission using an LDPC code. In group-wise interleaving, the LDPC code with a code length N of 69120 bits is interleaved in units of 360-bit bit groups 0 to 191. In group-wise deinterleaving, a sequence of the LDPC code after group-wise interleaving is returned to an original sequence. The present technology can be applied, for example, in a case of performing data transmission using an LDPC code, and the like.

The embodiments of the present disclosure provide a method and an apparatus for data processing with structured LDPC codes. The method includes: obtaining a code block size for structured LDPC coding; determining a coding expansion factor z based on at least one of the code block size, a parameter kb of a basic check matrix, a positive integer value p or the basic check matrix having mb rows and nb columns; and encoding a data sequence to be encoded, or decoding a data sequence to be decoded, based on the basic check matrix and the coding expansion factor. The present disclosure is capable of solving the problem in the related art associated with low flexibility in data processing with LDPC coding and improving the flexibility in data processing with LDPC coding.

An encoding method, decoding method, encoding device and decoding device for structured LDPC codes. The method includes: determining a basic matrix used for encoding, which includes K0 up-and-down adjacent pairs; and according to the basic matrix and an expansion factor corresponding to the basic matrix, performing an LDPC encoding operation of obtaining a codeword of Nb×z bits according to source data of (Nb−Mb)×z bits, herein z is the expansion factor, and z is a positive integer which is greater than or equal to 1. The provided technical solution is applicable to the encoding and decoding of the structured LDPC, thereby realizing the encoding and decoding of LDPC at the high pipeline speed.

An interleaving and mapping method and a deinterleaving and demapping method for an LDPC codeword are provided. The interleaving and mapping method comprises: performing first bit interleaving on a check part of the LDPC codeword to obtain a check bit stream; splicing an information bit part of the codeword and the check bit stream into a codeword after the first bit interleaving; dividing the codeword after the first bit interleaving into multiple consecutive bit subblocks in a predetermined length, and changing the order of the bit subblocks according to a corresponding permutation order (bit-swapping pattern) to form a codeword after second bit interleaving; dividing the codeword after the second bit interleaving into two parts, and writing the two parts into storage space in a column order respectively and reading the two parts from the storage space in a row order respectively to obtain a codeword after third bit interleaving; and performing constellation mapping on the codeword after the third bit interleaving according to a constellation diagram to obtain a symbol stream; the permutation orders (bit-swapping patterns) and the constellation diagrams used in the interleaving and mapping processing of LDPC codes with different code rates, code length and LDPC code tables are designed and optimized using theoretical analysis. The technical solution reduces the receiving threshold of the receiving end.