Error correction with iterations of belief propagation decoding and algebraic decoding

摘要

An ABP (Adaptive Belief Propagation) decoding apparatus (31) for decoding error correction codes such as RS, BCH or AG codes diagonalizes a parity check matrix, updates LLR values, decodes the LLR values using a soft or hard algebraic decoding algorithm and then adds a decoded word obtained by the decoding to a decoded word list. The ABP decoding apparatus (31) repeats the decoding procedure as inner repetitive decoding by a predetermined number of times. Further, as the ABP decoding apparatus (31) successively changes initial values for priority ranks of the LLR values, it repeats the inner repetitive decoding as outer repetitive decoding by a predetermined number of times. Then, the ABP decoding apparatus (31) selects an optimum one of the decoded words from within a decoded word list obtained by the repeated inner repetitive decoding.