2000 IEEE Digital Signal Processing Workshop

Fast Time-Domain Equalization for Discrete Multitone Modulation Systems

Biao Lu (1), Lloyd D. Clark (2), Guner Arslan (1), and Brian L. Evans (1)

(1) Department of Electrical and Computer Engineering, Engineering Science Building, The University of Texas at Austin, Austin, TX 78712-1084 USA
iambiao@yahoo.com - guner_arslan@hotmail.com - bevans@ece.utexas.edu

(2) Schlumberger, 8311 North FM 620 Road, Austin, TX 78726 USA
ldclark@austin.apc.slb.com

Paper - Poster

DMT TEQ Matlab Toolbox - ADSL Research at UT Austin

Abstract

In discrete multitone receivers, a time-domain equalizer (TEQ) shortens the effective channel impulse response. The effective channel impulse response is ideally non-zero inside a short window and zero elsewhere. The samples outside of the window cause intersymbol interference. The ratio between the samples inside and outside of this window is called the shortening signal-to-noise (SSNR). In this paper, we develop a suboptimal method for maximum SSNR TEQ design that requires two orders of magnitude fewer computations than the original maximum SSNR method. We reduce computation by using a proposed heuristic to estimate the optimal delay of the window and a proposed divide-and-conquer method to compute the TEQ taps. For typical ADSL channels, the tradeoff for the reduction in computation is roughly 4 dB SSNR for two-tap TEQs and less than 1 dB for 17-tap TEQs.

Last Updated 11/08/04.