Embodiments of this application disclose a example polar code encoding methods, example polar code decoding methods, and example apparatuses thereof. One example method in embodiments of this application includes generating an input vector, where the input vector includes T subblocks, a first information bit of a first subblock is obtained by replicating a second information bit of a second subblock, the first subblock and the second subblock arc subblocks of the T subblocks, a sequence number of the first subblock is after a sequence number of the second subblock, and T is an integer greater than or equal to 2. Polar encoding can then be performed on the input vector to obtain an encoded bit.

The present disclosure provides a method for optimizing a protograph-based LDPC code over an underwater acoustic (UAW) channel. The traditional protograph-based LDPC code over an UAW channel does not consider performance in an error floor region. The method first determines parameters such as a protograph-based LDPC code length, a basic protograph, a target decoding threshold, a threshold adjustment factor, and an ACE check parameter. The protograph is optimized, and the method constructs a parity check matrix by using a UAW channel-based PEG/ACE hybrid algorithm, performs ACE check on the parity check matrix, and calculates a decoding threshold for the matrix passing the check. If the decoding threshold is within a range of an iterative decoding threshold, the parity check matrix is a final optimized matrix. Otherwise, the method continues to optimize the protograph until a parity check matrix passing the check is obtained.

An encoding method includes obtaining to-be-encoded information and a mother code length N. The to-be-encoded information includes K information bits. The method also includes determining, based on K and N, a set I corresponding to subchannels of the information bits and a set F corresponding to subchannels of frozen bits. Information bits corresponding to subchannel sequence numbers in the set I are distributed in X outer component codes, a code length of each outer component code is B, and the X outer component codes includes a first-type outer component code and a second-type outer component code or the X outer component codes include a first-type outer component code, a second-type outer component code, and one third-type outer component code. Different types of component codes have different code rates. The method additionally includes performing polarization encoding based on the set I and the set F.

The present disclosure provides an encoding method and apparatus, and relates to the field of communications technologies, to reduce an encoding latency and complexity, and the amount of computation of real-time construction. The encoding method includes: obtaining information bits; determining a puncturing pattern, where the puncturing pattern includes an element in a puncturing set and an element in a shortening set, and the puncturing set and the shortening set have no intersection set; and performing, by using the determined puncturing pattern, rate matching on data obtained after the information bits are encoded.

Concepts and schemes pertaining to quasi-cyclic-low-density parity-check (QC-LDPC) coding are described. A processor of an apparatus may generate a QC-LDPC code having a plurality of codebooks embedded therein. The processor may select a codebook from the plurality of codebooks. The processor may also encode data using the selected codebook. Alternatively or additionally, the processor may generate the QC-LDPC code including at least one quasi-row orthogonal layer. Alternatively or additionally, the processor may generate the QC-LDPC code including a base matrix a portion of which forming a kernel matrix that corresponds to a code rate of at least a threshold value

A device for generating a multi-kernel polar code x.sub.N of length N and dimension K on the basis of a first transformation matrix G.sub.N of size N×N that defines a first multi-kernel polar code includes a processor configured to generate a second transformation matrix G′.sub.N of size N×N by permuting the order of at least two columns of a sub-matrix of the first transformation matrix G.sub.N, and generate the multi-kernel polar code x.sub.N an the basis of x.sub.N=u.sub.N.Math.G′.sub.N, wherein u.sub.N=(u.sub.0, . . . , u.sub.N−1) is a vector of size N, with the elements u.sub.i, i=0, . . . N−1, corresponding to an information bit if i∈I, I being a set of K information bit indices, and u.sub.i=0, if i∈F, F being a set of N−K frozen bit indices.

Systems, methods, and devices for encoding and decoding data packets for transmission across a data network. To encode, data packets are first subjected to a an outer code process to result in outer coded packets. The outer coded packets are then divided into generations or groups of outer coded packets, each group or generation having an equal number of packets. Output packets are then created by forming random linear combinations of the outer coded packets from a specific generation or group of outer coded packets. The coefficients for the various elements of each linear combination is selected from a Galois field of values. To decode the incoming packets, enough packets are received until an iterative decoding process can be initiated.

In an illustrative example, a method includes receiving data that includes a set of data symbols. The method further includes generating a set of parity symbols based on the set of data symbols using an erasure correcting code. The set of parity symbols includes at least a first parity symbol that is generated based on a first proper subset of the set of data symbols. The first parity symbol enables recovery of a data symbol of the first proper subset independently of a second proper subset of the set of data symbols.

The embodiments of the present application provide a polar code construction method and apparatus, which relate to the field of communications technology. The method comprises: obtaining a polar weight spectrum for each polarized channel; calculating an upper bound of error probability of each polarized channel based on the obtained polar weight spectrum, distribution probability density of a fading factor of a fading channel, and a signal-to-noise ratio of the fading channel; taking a logarithm of the calculated upper bound of the error probability for each polarized channel and obtaining a reliability metric of the polarized channel based on the taken logarithm, wherein the smaller the metric value is, the higher the reliability of the polarized channel is; sorting all polarized channels in an ascending order of the reliability metric and selecting part of the polarized channels having a lowest reliability metric for transmitting information bits and the remaining polarized channels for transmitting frozen bits. According to the embodiments of the present application, performing polar code construction under the condition of a fading channel can improve the efficiency of polar code construction.

The present disclosure provides a method for optimizing a protograph-based LDPC code over an underwater acoustic (UAW) channel. The traditional protograph-based LDPC code over an UAW channel does not consider performance in an error floor region. The method first determines parameters such as a protograph-based LDPC code length, a basic protograph, a target decoding threshold, a threshold adjustment factor, and an ACE check parameter. The protograph is optimized, and the method constructs a parity check matrix by using a UAW channel-based PEG/ACE hybrid algorithm, performs ACE check on the parity check matrix, and calculates a decoding threshold for the matrix passing the check. If the decoding threshold is within a range of an iterative decoding threshold, the parity check matrix is a final optimized matrix. Otherwise, the method continues to optimize the protograph until a parity check matrix passing the check is obtained.