Low complexity turbo decoding for binary hidden Markov channels

We describe parallel concatenated codes for communications over binary hidden Markov channels. We present a simplified decoding system that utilizes the a priori statistics of the channel and clearly outperforms systems based on the traditional approach of using a channel interleaver to create a channel which is assumed to be memoryless. Although the performance of this method is slightly worse than that of the best known methods, its main advantage (besides the reduced complexity) is that there is no need to change the turbo encoder structure depending on the channel parameters.