Power-of-two adaptive filters using Tabu Search

Digital filters with power-of-two or a sum of power-of-two coefficients can be built using simple and fast shift registers instead of slower floating- point multipliers, such a strategy can reduce both the VLSI silicon area an d the computational time. Due to the quantization and the nonuniform distri bution of the coefficients through their domain, in the case of adaptive fi lters, classical steepest descent based approaches cannot be successfully a pplied. Methods for adaptation processes, as in the least mean squares (LMS ) error and other related adaptation algorithms, can actually lose their co nvergence properties. In this brief, we present a customized Tabu Search (T S) adaptive algorithm that works directly on the power-of-two filter coeffi cients domain, avoiding any rounding process. In particular, we propose TS for a time varying environment, suitable for real time adaptive signal proc essing. Several experimental results demonstrate the effectiveness of the p roposed method.