Error control coding in ADSL DMT system.

Abstract

Asymmetric Digital Subscriber Line (ADSL) is an access technology intended to provide up to 8 Mbps downstream digital transmission from the central office to customers and up to 640 kbps upstream transmission over the existing nonloaded copper loop plant. The transfer characteristics of twisted pairs make high-speed data transmission very difficult. Sharply increasing attenuation with the increase of frequency makes the higher frequency band unavailable for transmission and also gives very severe inter-symbol-interference (ISI). In ADSL, instead of using conventional single carrier transmission the preferred approach is to employ discrete multitone (DMT) transmission. The main idea of DMT is to change a high-rate transmit data sequence into some frequency-division multiplexed low-rate data sequences. With narrow-band subchannels, DMT systems can make much better use of the bandwidth and furthermore, it can solve the ISI problem in a simple way. In this thesis, a performance evaluation structure of RS codes in ADSL DMT systems against stationary noises (including additive-white-Gaussian noise (AWGN) and crosstalk noise) is designed. (Abstract shortened by UMI.)