Fast Chase algorithm with an application in turbo decoding

Turbo product codes (TPCs) provide an attractive alternative to recursive s ystematic convolutional (RSC)-based turbo systems. Rather than employ trell is-based decoders, an algebraic decoder may be repeatedly employed in a low -complexity, soft-input/soft-output errors-and-erasures decoder such as the Chase algorithm. Taking motivation from efficient forced erasure decoders, this implementation re-orders the Chase algorithm's repeated decodings suc h that the inherent computational redundancy is greatly reduced without deg rading performance. The result is a highly efficient Fast Chase implementat ion; the algorithm presented here is principally applicable to single error -correcting codes although consideration is also given to the more general case. The new decoder's value in practical turbo schemes is demonstrated vi a application to decoding of the (64,57,4) extended Hamming TPC.