Joint iterative channel estimation and decoding in flat correlatedRayleigh fading

摘要

This paper addresses the design and performance evaluation withnrespect to capacity of M-PSK turbo-coded systems operating innfrequency-flat time-selective Rayleigh fading. The receiver jointlynperforms channel estimation and turbo decoding, allowing the twonprocesses to benefit from each other. To this end, we introduce ansuitable Markov model with a finite number of states, designed tonapproximate both the values and the statistical properties of thencorrelated flat fading channel phase, which poses a more severenchallenge to PSK transmission than amplitude hiding. Then, thenforward-backward algorithm determines both the maximum a posteriorinprobability (MAP) value for each symbol in the data sequence and the MAPnchannel phase in each iteration. Simulations show good performance innstandard correlated Rayleigh fading channels. A sequence ofnprogressively tighter upper bounds to the capacity of a simplifiednMarkov-phase channel is derived, and performance of a turbo code withnjoint iterative channel estimation and decoding is demonstrated tonapproach these capacity bounds