Encoding and decoding method and apparatus

An encoding method, comprising:

• obtaining, by a transmit device, N to-be-encoded vectors;
• encoding, by the transmit device, the N to-be-encoded vectors based on a polar code kernel matrix, to obtain N temporary code blocks;
• performing, by the transmit device, a mask operation on each target bit sequence of target bit sequences in an (n+1)th temporary code block to an (n+M)th temporary code block and a source bit sequence segment of an nth temporary code block, to obtain M mask bit sequences, wherein M is greater than or equal to 1 and is less than or equal to N−1, the target bit sequences are sub-sequences of the (n+1)th temporary code block to the (n+M)th temporary code block, a source bit sequence is a sub-sequence of the nth temporary code block, the source bit sequence segment is a sub-sequence of the source bit sequence, the source bit sequence segment is one of M source bit sequence segments, n is greater than or equal to 1 and is less than or equal to N−M, N is greater than or equal to 2, and n=1, 2, 3, . . . , N−M;
• encoding, by the transmit device, each of the M mask bit sequences based on the polar kernel matrix, to obtain M encoded mask bit sequences;
• summing, by the transmit device, the M encoded mask bit sequences and M temporary code blocks, to obtain M first code blocks, wherein an Mth first code block is obtained by summing an Mth encoded mask bit sequence and the (n+M)th temporary code block, and the M temporary code blocks comprise the (n+1)th temporary code block to the (n+M)th temporary code block;
• and
• sending, by the transmit device, a codeword, wherein the codeword comprises N code blocks, the N code blocks comprise the M first code blocks and N−M second code blocks, and the second code blocks are code blocks in the N temporary code blocks other than the M temporary code blocks.