Open Access

Analysis and Design of Timing Recovery Schemes for DMT Systems over Indoor Power-Line Channels

  • José Antonio Cortés1Email author,
  • Luis Díez1,
  • Eduardo Martos-Naya1,
  • Francisco Javier Cañete1 and
  • José Tomás Entrambasaguas1
EURASIP Journal on Advances in Signal Processing20072007:048931

https://doi.org/10.1155/2007/48931

Received: 31 October 2006

Accepted: 23 March 2007

Published: 22 May 2007

Abstract

Discrete multitone (DMT) modulation is a suitable technique to cope with main impairments of broadband indoor power-line channels: spectral selectivity and cyclic time variations. Due to the high-density constellations employed to achieve the required bit-rates, synchronization issues became an important concern in these scenarios. This paper analyzes the performance of a conventional DMT timing recovery scheme designed for linear time-invariant (LTI) channels when employed over indoor power lines. The influence of the channel cyclic short-term variations and the sampling jitter on the system performance is assessed. Bit-rate degradation due to timing errors is evaluated in a set of measured channels. It is shown that this synchronization mechanism limits the system performance in many residential channels. Two improvements are proposed to avoid this end: a new phase error estimator that takes into account the short-term changes in the channel response, and the introduction of notch filters in the timing recovery loop. Simulations confirm that the new scheme eliminates the bit-rate loss in most situations.

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Authors’ Affiliations

(1)
Departamento de Ingeniería de Comunicaciones, Escuela Técnica Superior de Ingeniería de Telecomunicación, Universidad de Málaga

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Copyright

© José Antonio Cortés et al 2007

This article is published under license to BioMed Central Ltd. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.