MAP symbol decoding in channels with error bursts

We analyze the forward-backward algorithm for the maximum a posteriori (MAP) decoding of information transmitted over channels with memory and propose a suboptimal forward-only algorithm. We assume that both the information source and channel are described using hidden Markov models (HMMs). The algorithm lends itself to parallel implementation and pipelining. We apply the algorithm to MAP decoding of symbols which were trellis-code modulated and transmitted over channels with error bursts.