SOURCE-AIDED TRELLIS DECODING FOR MOBILE COMMUNICATION CHANNELS

A trellis decoder which incorporates the residual redundancy in low bi t rate speech coder parameters is used to decode Reed Solomon (RS) cod es. As not all the transmitted speech parameters and bits are equally sensitive to errors, unequal error protection has been employed to enh ance speech quality. Subcodes of RS codes, which have been introduced by Shin and Sweeney (1995), are used for this purpose. A trellis decod ing method is tailored to combat bursty errors in a mobile communicati on channel. Simulation results on a land mobile channel show a noticea ble increase in performance and computational efficiency of the decode r.