Blind Crosstalk Cancellation for DMT Systems

Dr. Nirmal Warke and Mr. Nadeem Ahmed

Texas Instruments

Friday, October 4th, 3:00 PM, ENS 637

Abstract

As the deployment of broadband communication systems such as DSL continues to grow, system performance in terms of capacity and error rates is severely limited by crosstalk interference. In order to continue deploying high speed DSL service, it becomes necessary to mitigate this crosstalk interference. All current crosstalk mitigation techniques require precise knowledge of the crosstalk coupling functions between the twisted pair wires carrying DSL service within a cable binder. In practice, this is near impossible to obtain, without coordination between the different DSL services.

In this talk, we present a crosstalk cancellation technique that is blind to the coupling functions between the wire pairs. Our technique uses the statistical properties of the received crosstalk signal (that can be easily estimated), rather than the exact coupling functions themselves, making it very attractive for practical implementation. We show with the help of simulations for a realistic ADSL system with HDSL and T1 crosstalk interference using actual measured crosstalk coupling functions that the proposed blind crosstalk cancellation technique can achieve significant gains in terms of rate and reach improvement for the ADSL system. We also show that the performance of the proposed blind crosstalk cancellation technique is robust to a jitter in the crosstalk symbol timing estimate that is required to construct the cancellation signal.

Biography

Nirmal Warke received his BTech degree from the Indian Institute of Technology-Bombay in 1993 and his PhD degree in Information Technology from George Mason University in 1997. During 1997, he was a visiting research scholar at Rice University working on the application of Information theory to detection & estimation problems in communications.

Nirmal is currently with the DSP Solutions R&D Center at Texas Instruments- Dallas. He has been working on wireline communications including V.90/V.92 voiceband technology and DSL technology. His areas of interest include detection, estimation and modulation theory.

Nadeem Ahmed received his B.Sc. degree from the University of Manitoba in 1998, and his M.S. degree from Rice University, both from the department of Electrical and Computer Engineering. He is currently a Ph.D. student at Rice University in the department of Electrical and Computer Engineering. He is a member of the Digital Signal Processing group, where he is a Texas Instruments Fellow, and NSERC PGS A and B recipient.

Nadeem has spent time working with research centers including Telecommunications Research Laboratories (TRLabs), Nokia's R & D center, and Texas Instruments DSP Solutions R & D center. His research interests lie in signal processing techniques for communications. His work has focused on modulation, detection, equalization and power distribution techniques for both wireline and wireless applications.

A list of Wireless Networking and Communications Seminars is available at from the ECE department Web pages under "Seminars". The Web address for the Wireless Networking and Communications Seminars is http://signal.ece.utexas.edu/seminars