Data retransmission method and related apparatus

A method of data transmission, comprising:

• receiving, by a receiving apparatus from a transmitting apparatus, a first data frame comprising an initial codeword and a check codeword, the check codeword is obtained after the initial codeword is encoded based on a first check matrix, and the initial codeword has a plurality of codeword groups;
• recognizing, by the receiving apparatus, at least one erroneous codeword group in the initial codeword;
• sending, by the receiving apparatus, an error indication message to the transmitting apparatus, wherein the error indication message carries an identifier of the at least one erroneous codeword group;
• obtaining, by the receiving apparatus from a transmitting apparatus based on the error indication message, a second data frame comprising a partial sub check codeword, the partial sub check codeword is a part of a sub check codeword, and the sub check codeword is obtained after the at least one erroneous codeword group is encoded by using a second check matrix;
• and
• decoding, by the receiving apparatus, the partial sub check codeword, the initial codeword, and the check codeword by using a third check matrix, to obtain the initial codeword, wherein the third check matrix is obtained based on the first check matrix, the second check matrix, and a location of the at least one erroneous codeword group in the initial codeword.