Equalization of rapid selective fadings with unknown and time-varying forms

This paper presents a new equalizer for rapidly time varying selective fading without an apriori information about the shape of that fading in frequency domain. The basic idea is to analyze the output of the channel by a set of adjacent filters covering the band of channel. Then, a gradient algorithm is used to identify frequency bands at which fading takes place and an other gradient algorithm is used to adapt only the gains of filters lying in vicinity of fading. This idea enables a high tracking speed for the equalizer and enables equalization of rapid fadings that are beyond the capabilities of presently existing equalizers.