Adaptive Baum-Welch algorithms for frequency-selective fading channels

The problem of adaptive equalization of the time-varying frequency-selective channel is studied by using the adaptive Baum-Welch algorithm. In particular, blind LMS and blind RLS channel estimators are derived and they are combined with the well-known forward-backward processing SISO algorithm for known channels. An application of the proposed algorithms to the iterative "turbo-processing" receivers illustrated how the blind LMS and blind RLS estimators can efficiently utilize the extrinsic information obtained from the decoder SISO in order to enhance their estimation accuracy