An interactive concatenated turbo coding system

Although turbo codes with iterative decoding have been shown to achieve bit-error rates (BER) close to the Shannon limit, they suffer from three disadvantages: a large decoding delay, an error floor at low BER, and a relatively poor frame error performance (FER). This paper presents an interactive concatenated turbo coding system in which a Reed-Solomon outer code is concatenated with a binary turbo inner code. In the proposed system, the outer code decoder and the inner turbo code decoder interact to achieve both good bit error and frame error performances. Also presented is an effective criterion for stopping the iterative decoding process and a new reliability-based decoding algorithm called the Chase-GMD algorithm for nonbinary codes.