On iterative decoding in some existing systems

Iterative decoding is used to achieve backward compatible performance impro vement in several existing systems. Concatenated coding and iterative decod ing are first set up using composite mappings, so that various applications in digital communication and recording can be described in a concise and u niform manner. An ambiguity zone detection (AZD) based iterative decoder, o perating on generalized erasures, Is described as an alternative for concat enated systems where turbo decoding cannot be performed. Described iterativ e decoding techniques are then applied to selected wireless communication a nd digital recording systems. Simulation results and utilization of decodin g gains are briefly discussed.