tailieunhanh - Báo cáo hóa học: " A Novel Efficient Cluster-Based MLSE Equalizer for Satellite Communication Channels with M-QAM Signaling"

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: A Novel Efficient Cluster-Based MLSE Equalizer for Satellite Communication Channels with M-QAM Signaling | Hindawi Publishing Corporation EURASIP Journal on Applied Signal Processing Volume 2006 Article ID 34343 Pages 1-16 DOI ASP 2006 34343 A Novel Efficient Cluster-Based MLSE Equalizer for Satellite Communication Channels with M-QAM Signaling Eleftherios Kofidis 1 Vassilis Dalakas 2 Yannis Kopsinis 3 and Sergios Theodoridis2 1 Department of Statistics and Insurance Science University of Piraeus 80 Karaoli Dimitriou Street 185 34 Piraeus Greece 2 Department of Informatics and Telecommunications University of Athens Panepistimioupolis Ilissia 157 84 Athens Greece 3 Institute for Digital Communications School of Engineering and Electronics the University of Edinburgh Kings Buildings Mayfield Road Edinburgh EH9 3JL UK Received 24 April 2005 Revised 19 December 2005 Accepted 18 February 2006 Recommended for Publication by Bernard Mulgrew In satellites nonlinear amplifiers used near saturation severely distort the transmitted signal and cause difficulties in its reception. Nevertheless the nonlinearities introduced by memoryless bandpass amplifiers preserve the symmetries of the M-ary quadrature amplitude modulation M-QAM constellation. In this paper a cluster-based sequence equalizer CBSE that takes advantage of these symmetries is presented. The proposed equalizer exhibits enhanced performance compared to other techniques including the conventional linear transversal equalizer Volterra equalizers and RBF network equalizers. Moreover this gain in performance is obtained at a substantially lower computational cost. Copyright 2006 Hindawi Publishing Corporation. All rights reserved. 1. INTRODUCTION The role of a satellite is to receive a signal from an earth station or another satellite uplink and acting as a simple repeater to transmit it to another earth station or satellite downlink 1 . The need to maximally exploit on-board resources in a satellite communication system often imposes driving a high power amplifier HPA such as the traveling wave tube amplifier TWTA