Equalization algorithms for ADSL DMT system.

Abstract

Discrete Multitone can achieve high capacity over Asymmetric Digital Subscriber Lines by dividing the transmission band into a number of subchannels and thus partially compensating for the nonideal channel response. Performance improvements can be obtained by judiciously designing a time domain equalizer, a frequency domain equalizer, and by suitable selection of a cyclic prefix. The transceiver front-end filter selection is also very important. In this thesis, we discuss the time domain equalizer design algorithms and the filter selection. The system performance with different filters is analyzed based on computer simulations. We then theoretically analyze the effects of the remaining distortion on the system performance and verify the results by simulations. We propose an optimized frequency domain equalizer for discrete multitone systems. Our simulation results show that the achievable bit rate over a given loop length is significantly increased with the new frequency domain equalizer design.