Adaptive decision feedback equalizer with set-membership affine projection algorithm

Abstract

In this paper, a data-reusing algorithm with non-zero decision boundaries for data-selective updating of the coefficients of a decision feedback equalizer (DFE) is investigated for time-varying frequency selective wireless channels. Here, the coefficients of both the feed-forward filter (FFF) and the feedback filter (FBF) are adaptively updated using set-membership affine projection algorithm. It's performance is analyzed through simulations using ITU-R recommended wireless channel models. It is shown that, this scheme offers substantial computational savings while keeping the bit error rate (BER) and convergence performance almost similar to channel equalization with the data reusing affine projection algorithms. It is also demonstrated that, this channel equalization method yields faster convergence and better BER than the existing set-membership normalized least mean square (NLMS) algorithm based scheme.