Product accumulate codes: properties and performance

A new class of codes, named product accumulate codes, which are the concatenation of an outer product code and an inner rate-1 differential encoder (or accumulator) is proposed. We show that these codes can perform within a few tenths of a dB from the Shannon limit for rates/spl ges/1/2. For practical block lengths, these codes provide similar performance to turbo codes but with significantly lower decoding complexity.