Generalized structural subband implementation of adaptive FIR filters

An adaptive structure based on a generalised structural subband decomposition of finite-impulse-response (FIR) filters is presented. The proposed structure implements an adaptive FIR filter of length N as a parallel connection of L branches, with each branch composed of a cascade of a fixed interpolator and a sparse adaptive subfilter containing at least N/L non-zero coefficients. The proposed structure presents superior convergence performance for colored input signals when compared to the conventional direct-form least-mean-square (LMS) structure, with a very small increase in the number of operations. The advantages of using the subband structure in the acoustic echo canceller and channel equalizer applications are shown through computer simulation results