Joint message-passing decoding of a differential code and a channel code

摘要

Embodiments provide an apparatus, a method and a computer program for decoding a received codeword derived from an optical signal. The received codeword is based on a transmit codeword, which is encoded by the forward error correction encoding rule of a LDPC code or an IRA code and by a differential encoding rule. The apparatus (10) is operable to decode the received codeword based on a joint decoding scheme, the joint decoding scheme being based on a combination of a differential decoding rule associated to the differential encoding rule and a forward error correction decoding rule associated to the forward error correction encoding rule by passing messages between check nodes and variable nodes on a single Tanner graph representing both rules.