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Báo cáo hóa học: " Research Article Analysis and Design of Timing Recovery Schemes for DMT Systems over Indoor Power-Line Channels"

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: Research Article Analysis and Design of Timing Recovery Schemes for DMT Systems over Indoor Power-Line Channels | Hindawi Publishing Corporation EURASIP Journal on Advances in Signal Processing Volume 2007 Article ID 48931 11 pages doi 10.1155 2007 48931 Research Article Analysis and Design of Timing Recovery Schemes for DMT Systems over Indoor Power-Line Channels Josts Antonio Cortes Luis Diez Eduardo Martos-Naya Francisco Javier Cariete and Josts Tomcis Entrambasaguas Departamento de Ingenieria de Comunicaciones Escuela Tecnica Superior de Ingenieria de Telecomunicacion Universidad de Malaga 29071 Malaga Spain Received 31 October 2006 Accepted 23 March 2007 Recommended by Moises Vidal Ribeiro 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. Copyright 2007 Jose Antonio Cortes et al. 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. 1. INTRODUCTION The increasing demand .