tailieunhanh - Báo cáo hóa học: "Near-Capacity Coding for Discrete Multitone Systems with Impulse Noise"

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: Near-Capacity Coding for Discrete Multitone Systems with Impulse Noise | Hindawi Publishing Corporation EURASIP Journal on Applied Signal Processing Volume 2006 Article 1D98738 Pages 1-10 DOI ASP 2006 98738 Near-Capacity Coding for Discrete Multitone Systems with Impulse Noise Masoud Ardakani 1 Frank R. Kschischang 2 and Wei Yu2 1 Department of Electrical and Computer Engineering University of Alberta ECERF Building Edmonton AB Canada T6G 2V4 2 Department of Electrica and Computer Engineering University of Toronto 10 King s College Road Toronto ON Canada M5S 3G4 Received 1 December 2004 Revised 28 April 2005 Accepted 9 June 2005 We consider the design of near-capacity-achieving error-correcting codes for a discrete multitone DMT system in the presence of both additive white Gaussian noise and impulse noise. Impulse noise is one of the main channel impairments for digital subscriber lines DSL . One way to combat impulse noise is to detect the presence of the impulses and to declare an erasure when an impulse occurs. In this paper we propose a coding system based on low-density parity-check LDPC codes and bit-interleaved coded modulation that is capable of taking advantage of the knowledge of erasures. We show that by carefully choosing the degree distribution of an irregular LDPC code both the additive noise and the erasures can be handled by a single code thus eliminating the need for an outer code. Such a system can perform close to the capacity of the channel and for the same redundancy is significantly more immune to the impulse noise than existing methods based on an outer Reed-Solomon RS code. The proposed method has a lower implementation complexity than the concatenated coding approach. Copyright 2006 Hindawi Publishing Corporation. All rights reserved. 1. INTRODUCTION The design of error control codes for discrete multitone DMT systems is of great interest for applications such as digital subscriber lines DSL 1-6 . In a DMT system different constellations maybe used in different tones and nonbinary high-order modulation