Concatenated code encoding method, concatenated code decoding method, and communication apparatus

A concatenated code decoding method, comprising:

• obtaining a channel receive vector whose length is Ni, wherein Ni is a length of an inner code of a concatenated code, the inner code of the concatenated code is an optimized low-density parity-check (LDPC) code, an outer code of the concatenated code is a polar code, and Ni is a positive integer;
• decoding the channel receive vector by using a soft input soft output (SISO) decoding algorithm of the optimized LDPC code, to obtain a first soft information sequence whose length is Ni;
• de-interleaving the first soft information sequence to obtain a de-interleaved first soft information sequence, and extracting soft information at first N_o locations in the de-interleaved first soft information sequence to obtain a second soft information sequence, wherein N_o is a length of the outer code of the concatenated code, and N_o is a positive integer;
• performing soft information iterative decoding by using a soft successive cancellation list (SCL) decoding algorithm of the polar code and the SISO decoding algorithm of the optimized LDPC code based on the second soft information sequence, the channel receive vector, and a preset maximum iteration quantity of times of the concatenated code, to obtain a third soft information sequence;
• performing a hard decision on the third soft information sequence to obtain a decoded candidate sequence;
• and
• outputting the decoded candidate sequence.

A communication apparatus, comprising:

• a communication interface, the communication interface configured to obtain a to-be-encoded message bit sequence;
• at least one processor, configured to:
• perform polar code encoding on the to-be-encoded message bit sequence based on a frozen bit set and a message bit set that are of a first polar code, to obtain a first encoded code word whose length is N_o;
• interleave the first encoded code word to obtain a second encoded code word;
• and
• perform optimized low-density parity-check (LDPC) code encoding on the second encoded code word to obtain a concatenated code word, wherein:
• the interleaving comprises outer interleaving and inner interleaving, wherein:
• the outer interleaving comprises:
• mapping R frozen bits in the frozen bit set of the first polar code to R rows of a generator matrix of the optimized LDPC code, wherein row weights of the R rows are lower than or equal to row weights of rows of the generator matrix other than the R rows, and
• mapping (N_o−R) message bits in the message bit set of the first polar code to remaining (N_o−R) rows of the generator matrix of the optimized LDPC code other than the R rows;
• and
• the inner interleaving comprises:
• interleaving on the R frozen bits in the frozen bit set of the first polar code and interleaving on the (N_o−R) message bits in the message bit set of the first polar code;
• and
• wherein the communication interface is further, configured to output the concatenated code word.