Blind equalization of quadrature partial response-trellis coded modulated signals in Rician fading

In this paper, a blind maximum-likelihood channel estimation algorithm is developed for quadrature partial response-trellis coded modulated (QPR-TCM) signals propagating through a Rician fading environment. A hidden Markov model (HMM) formulation of the problem is introduced and the Baum-Welch parameter estimation algorithm is modified to provide a computationally efficient solution to the resulting optimization problem. Performance analysis of the proposed method is carried out through the evaluation of bit-error probability upper bound for Rician fading channels. Also, some illustrative simulations are presented.