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Báo cáo hóa học: " Research Article Cyclostationarity-Inducing Transmission Methods for Recognition among OFDM-Based Systems"

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 Cyclostationarity-Inducing Transmission Methods for Recognition among OFDM-Based Systems | Hindawi Publishing Corporation EURASIP Journal on Wireless Communications and Networking Volume 2008 Article ID 586172 14 pages doi 10.1155 2008 586172 Research Article Cyclostationarity-Inducing Transmission Methods for Recognition among OFDM-Based Systems Koji Maeda Anass Benjebbour Takahiro Asai Tatsuo Furuno and Tomoyuki Ohya Research Laboratories NTT DoCoMo Inc. 3-5 Hikari-no-oka Yokosuka Kanagawa 239-8536 Japan Correspondence should be addressed to Koji Maeda maedakou@nttdocomo.co.jp Received 29 June 2007 Revised 14 December 2007 Accepted 18 March 2008 Recommended by Ivan Cosovic This paper proposes two cyclostationarity-inducing transmission methods that enable the receiver to distinguish among different systems that use a common orthogonal frequency division multiplexing- OFDM- based air interface. Specifically the OFDM signal is configured before transmission such that its cyclic autocorrelation function CAF has peaks at certain preselected cycle frequencies. The first proposed method inserts a specific preamble where only a selected subset of subcarriers is used for transmission. The second proposed method dedicates a few subcarriers in the OFDM frame to transmit specific signals that are designed so that the whole frame exhibits cyclostationarity at preselected cycle frequencies. The detection probabilities for the proposed cyclostationarity-inducing transmission methods are evaluated based on computer simulation when optimum and suboptimum detectors are used at the receiver. Copyright 2008 Koji Maeda 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 In recent years cognitive radio has attracted much attention as a key solution towards accommodating several wireless communication systems in the same frequency band 13 . Cognitive radio devices are equipped with the .