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 Robust OFDM Timing Synchronisation in Multipath Channels | Hindawi Publishing Corporation EURASIP Journal on Wireless Communications and Networking Volume 2008 Article ID 675048 12 pages doi 2008 675048 Research Article Robust OFDM Timing Synchronisation in Multipath Channels C. Williams 1 2 S. McLaughlin 3 and M. A. Beach1 1 Centre for Communications Research Bristol University Woodland Road Bristol BS8 1UB UK 2 Hayes Fujitsu Laboratories of Europe London UB4 8FE UK 3 Institute for Digital Communications University of Edinburgh Mayfield Road Edinburgh EH9 3JL UK Correspondence should be addressed to C. Williams Received 11 September 2007 Revised 19 February 2008 Accepted 21 April 2008 Recommended by Athina Petropulu This paper addresses pre-FFT synchronisation for orthogonal frequency division multiplex OFDM under varying multipath conditions. To ensure the most efficient data transmission possible there should be no constraints on how much of the cyclic prefix CP is occupied by intersymbol interference ISI . Here a solution for timing synchronisation is proposed that is robust even when the strongest multipath components are delayed relative to the first arriving paths. In this situation existing methods perform poorly whereas the solution proposed uses the derivative of the correlation function and is less sensitive to the channel impulse response. In this paper synchronisation of a DVB single-frequency network is investigated. A refinement is proposed that uses heuristic rules based on the maxima of the correlation and derivative functions to further reduce the estimate variance. The technique has relevance to broadcast OFDMA and WLAN applications and simulations are presented which compare the method with existing approaches. Copyright 2008 C. Williams 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 .
