A Novel Low-Power High-Precision Implementation for Sign–Magnitude DLMS Adaptive Filters

Abstract

This paper investigates the use of approximate fixed-width and static segment multipliers in the design of Delayed Least Mean Square (DLMS) adaptive filters based on the sign–magnitude representation for the error signal. The fixed-width approximation discards part of the partial product matrix and introduces a compensation function for minimizing the approximation error, whereas the static segmented multipliers reduce the bit-width of the multiplicands at runtime. The use of sign–magnitude representation for the error signal reduces the switching activity in the filter learning section, minimizing power dissipation. Simulation results reveal that, by properly sizing the two approaches, a steady state mean square error practically unchanged with respect to the exact DLMS can be achieved. The hardware syntheses in a 28 nm CMOS technology reveal that the static segmented multipliers perform better in the learning section of the filter and are the most efficient approach to reduce area occupation, while the fixed-width multipliers offer the best performances in the finite impulse response section and provide the lowest power dissipation. The investigated adaptive filters overcome the state-of-the-art, exhibiting an area and power reduction with respect to the standard implementation up to −18.0% and −64.1%, respectively, while preserving the learning capabilities.

Design of Generalized Enhanced Static Segment Multiplier with Minimum Mean Square Error for Uniform and Nonuniform Input Distributions

“…In telecommunication, the suppression of noise in transceivers, necessary for improving the receiver sensitivity, requires cancellation methods based on adaptive filtering [4][5][6]. The huge number of multipliers, used for adaptation, increases the power consumption and demands specific techniques aimed to reduce area and power while preserving the quality of results [7][8][9][10][11]. Low-power designs are also required for audio applications [12] in which banks of filters realize operations as equalization and denoising.…”