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Báo cáo hóa học: " A Frame Synchronization and Frequency Offset Estimation Algorithm for OFDM System and its Analysis"

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 Frame Synchronization and Frequency Offset Estimation Algorithm for OFDM System and its Analysis | Hindawi Publishing Corporation EURASIP Journal on Wireless Communications and Networking Volume 2006 Article ID 57018 Pages 1-16 DOI 10.1155 WCN 2006 57018 A Frame Synchronization and Frequency Offset Estimation Algorithm for OFDM System and its Analysis Ch. Nanda Kishore1 and V. Umapathi Reddy1 2 1 Hellosoft India Pvt Ltd 82 703 Road No 12 Banjara Hills 500 034 Hyderabad AP India 2IIIT Hyderabad India Received 13 July 2005 Revised 12 December 2005 Accepted 19 January 2006 Recommended for Publication by Hyung-Myung Kim Orthogonal frequency division multiplexing OFDM is a parallel transmission scheme for transmitting data at very high rates over time dispersive radio channels. In an OFDM system frame synchronization and frequency offset estimation are extremely important for maintaining orthogonality among the subcarriers. In this paper for a preamble having two identical halves in time a timing metric is proposed for OFDM frame synchronization. The timing metric is analyzed and its mean values at the preamble boundary and in its neighborhood are evaluated for AWGN and for frequency selective channels with specified mean power profile of the channel taps and the variance expression is derived for AWGN case. Since the derivation of the variance expression for frequency selective channel case is tedious we used simulations to estimate the same. Based on the theoretical value of the mean and estimate of the variance we suggest a threshold for detection of the preamble boundary and evaluating the probability of false and correct detections. We also suggest a method for a threshold selection and the preamble boundary detection in practical applications. A simple and computationally efficient method for estimating fractional and integer frequency offset using the same preamble is also described. Simulations are used to corroborate the results of the analysis. The proposed method of frame synchronization and frequency offset estimation is applied to the downlink .