Soft-decision decoding of nonbinary codes

Cyclic and modified cyclic codes can provide greater decoding capability due to the increased length as opposed to Reed-Solomon codes where the lengths are equal to the field size. In this paper, an algorithm is presented which uses the algebraic structure of the codes to provide efficient soft-decision decoding. Use of this decoding algorithm for systems using nonbinary shortened cyclic codes and M-ary orthogonal signaling is presented. An improvement in performance is shown using modified cyclic codes over traditional systems using Reed-Solomon codes and M-ary orthogonal signaling when using the soft-decision decoding algorithm.