Abstract:

As for the sum-product decoding algorithm of low density parity check (LDPC) codes, a difference-based decoding method is proposed. The main idea is shown as follows: the messages passed on the bipartite graph of LDPC are based on the probability differences，and the updates of both check nodes and message nodes are carried out on some special addition domain. As for the update of check nodes, only some lowest differences can be selected for reducing computational complexity. In contrast with the traditional log-likelyhood-ratio-based（LLR-based） decoding method, the proposed method has much lower complexity, while it has no obvious loss of performance and convergence.

Key words: low density parity check codes, sum-product decoding algorithm, difference-based decoding algorithm