Open Access

Joint Frequency Ambiguity Resolution and Accurate Timing Estimation in OFDM Systems with Multipath Fading

EURASIP Journal on Wireless Communications and Networking20062006:062173

DOI: 10.1155/WCN/2006/62173

Received: 29 May 2005

Accepted: 4 November 2005

Published: 20 March 2006

Abstract

A serious disadvantage of orthogonal frequency-division multiplexing (OFDM) is its sensitivity to carrier frequency offset (CFO) and timing offset (TO). For many low-complexity algorithms, the estimation ambiguity exists when the CFO is greater than one or two subcarrier spacing, and the estimated TO is also prone to exceeding the ISI-free interval within the cyclic prefix (CP). This paper presents a method for joint CFO ambiguity resolution and accurate TO estimation in multipath fading. Maximum-likelihood (ML) principle is employed and only one pilot symbol is needed. Frequency ambiguity is resolved and accurate TO can be obtained simultaneously by using the fast Fourier transform (FFT) and one-dimensional (1D) search. Both known and unknown channel order cases are considered. Computer simulations show that the proposed algorithm outperforms some others in the multipath fading channels.

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Authors’ Affiliations

(1)
National Laboratory of Radar Signal Processing, Xidian University
(2)
Department of Communication and Information Engineering, Guilin University of Electronic Technology

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Copyright

© Jun Li et al. 2006

This article is published under license to BioMed Central Ltd. 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.