Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Joint Multiuser Detection and Optimal Spectrum Balancing for Digital Subscriber Lines | Hindawi Publishing Corporation EURASIP Journal on Applied Signal Processing Volume 2006 Article ID 80941 Pages 1-13 DOI ASP 2006 80941 Joint Multiuser Detection and Optimal Spectrum Balancing for Digital Subscriber Lines Vincent M. K. Chan and Wei Yu The Edward S. Rogers Sr. Department of Electrical and Computer Engineering University of Toronto Toronto ON Canada M5S3G4 Received 1 December 2004 Revised 27 April 2005 Accepted 8 July 2006 In a digital subscriber line DSL system with strong crosstalk the detection and cancellation of interference signals have the potential to improve the overall data rate performance. However as DSL crosstalk channels are highly frequency selective and multiuser detection is suitable only when crosstalk is strong the set of frequency tones in which multiuser detection may be used must be carefully chosen. Further this problem of tone selection is highly coupled with the transmit power spectra of both direct and interfering signals so the optimal solution requires the tone selection problem to be solved jointly with the multiuser spectrum optimization problem. The main idea of this paper is that the above joint optimization may be done efficiently using a dual decomposition technique similar to that of the optimal spectrum balancing algorithm. Simulations show that multiuser detection can increase the bit rate performance in a remotely deployed ADSL environment. Rate improvement is also observed when near-end crosstalk is estimated and cancelled in a VDSL environment with overlapping upstream and downstream frequency bands. Copyright 2006 Hindawi Publishing Corporation. All rights reserved. 1. INTRODUCTION Crosstalk noise is a major limiting factor in wideband digital subscriber line DSL systems. Current research has focused on dynamic spectrum management DSM techniques for mitigating the effect of crosstalk 1 . The goal of DSM is to facilitate cooperation among mutually interfering lines in a binder. Cooperation may be .
