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: Efficient Bidirectional DFE for Doubly Selective Wireless Channels | Hindawi Publishing Corporation EURASIP Journal on Applied Signal Processing Volume 2006 Article iD 70572 Pages 1-10 DOI ASP 2006 70572 Efficient Bidirectional DFE for Doubly Selective Wireless Channels Stefano Tomasin Department of Information Engineering University of Padova Via Gradenigo 6 B 35131 Padova Italy Received 1 June 2005 Revised 3 November 2005 Accepted 7 November 2005 The bidirectional decision feedback equalizer DFE performs two equalizations one on the received signal and one on its time-reversed version. In this paper we apply the bidirectional DFE to wireless transmissions on rapidly time-varying dispersive channels and we propose an efficient implementation obtained by implementing the feedforward filter in the frequency domain. The feedback filter is adapted to the channel variations within one block and we propose a simplified design of the feedback filter coefficients based on a polynomial model of channel variations. Simulations performed on time-varying channels show that the proposed structure significantly outperforms existing architectures. Copyright 2006 Hindawi Publishing Corporation. All rights reserved. 1. INTRODUCTION Recent developments in wireless communications have seen the extension to mobile applications of existing standards originally conceived for static receivers 1-4 . The push to provide access to wideband services on mobile terminals has posed a number of issues in the design of transmit and receive physical layers. In particular the channel on which communication takes place is affected by both frequency selectivity and time selectivity thus yielding a time-varying intersymbol interference ISI on the received signal. In order to compensate for the distortion introduced by doubly selective channels equalization is required. Among various equalization techniques we mention the block linear equalizer BLE 5 6 which has a high complexity since it requires the inversion and multiplication of huge matrices. The .
