A novel error-correcting codec for M-ary orthogonal modulations

Abstract

A new and novel codec (coder-decoder) combining trellis coding with an M-ary orthogonal modulation is presented for application in wideband channels. The codec provides satisfactory bit error rates at lower transmitted signal power levels. Current popular coding schemes which combine coding and modulation, such as trellis coded modulation (TCM), have only been applied to narrowband channels (e.g. telephony). Looking from precisely the opposite perspective, this work assumes a large bandwidth and high dimensional signal sets. A novel trellis design affording a decoding scheme which overcomes the large computational burden of this scenario is demonstrated. Simulation results indicate that, for sufficiently high dimensionality, acceptable bit error rates are achievable with SNRs which begin to approach the Shannon limit.