US Patent 11843393 Method and apparatus for decoding with trapped-block management

A method and apparatus for decoding in which a first failed decode operation is performed on raw bit values of a FEC block by a LDPC decoder. When the FEC block is determined to be a trapped block an updated LLR map is generated; the updated LLR map and either the raw bit values of the FEC block or a failed-decode-output-block from a previous failed decode operation on the trapped block are provided to the LDPC decoder; a decode operation of the LDPC decoder is performed using the updated LLR map on the bit values of the FEC block or the failed-decode-output-block from the previous failed decode operation; and the generating, the providing and the performing are repeated until the decode operation is successful or until a predetermined number of trapped-block-decoding iterations have been performed. When the decode operation is successful in decoding the FEC block the codeword is output.