Joint Protocol and Channel Decoding: An overview

Robust reception of audiovisual signals (and especially video) has been widely studied, demonstrating that the so-called Joint Source and Channel Decoding (JSCD) approach could improve the receiver performance while being compatible with existing standards (in fact they make the best possible use of the received data). However, in contrast with most approaches dealing with the cross layer strategy, JSCD does not take into account the actual structure of the communication chain, in which the network layers packetize the data, add headers, etc. Several consequences resulted from this fact: (i) JSCD is not making use of redundancies that are introduced by the network layers, e.g., CRCs, even if this redundancy may be quite large; (ii) JSCD is implicitly assuming that a large part of the actual bitstream (essentially headers of all sorts) was received without errors; (iii) JSCD in its initial statement is not compliant with most transmission systems. Joint Protocol and Channel Decoding, to be used jointly with JSCD intends to solve these inconsistencies.