Low-complexity forward-backward decoding method based on weighted editing distance

bdwdxxyyllThe invention discloses a low-complexity forward-backward decoding method based on a weighted editing distance, and the method comprises the steps: enabling a binary information sequence b to generate a code word sequence d with the length of NL symbols through an LDPC (Low Density Parity Check) code encoder; the mark codes w are uniformly inserted into the code word sequence d, and a sending code word x with the length of Nc is generated and output; after the sending code word x passes through the insertion/deletion-substitution channel, generating a receiving sequence y with the length of 1; the watermark decoder decodes the receiving sequence y by using low-complexity forward-backward decoding, and outputs a likelihood ratio sequence l; and the LDPC decoder performs decoding by using the likelihood ratio sequence 1, and the calculation result of the intermediate metric value is stored in the lookup table, so that the repeated calculation times of the intermediate metric value are reduced, the cal