BIT-LEVEL SOFT-DECISION DECODING OF REED-SOLOMON CODES

In this paper, we present a Reed-Solomon decoder that makes use of bit-level soft-decision information. A Reed-Solomon generator matrix which possesses a certain inherent structure in GF(2) is derived. This structure enables representation of the code as a union of cosets, each coset being an interleaver of several binary BCH codes. Such partition into cosets provides a clue for efficient bit-level soft-decision decoding. Two decoding algorithms are derived. In the development of the first algorithm we assume a memoryless channel, which makes the value of this algorithm more conceptual than practical. The second algorithm, which is obtained as a modification of the first, does account for channel memory and thus accommodates a bursty channel. Both decoding algorithms are in many cases orders of magnitude more efficient than conventional techniques.