Open Access

Estimation and Direct Equalization of Doubly Selective Channels

EURASIP Journal on Advances in Signal Processing20062006:062831

https://doi.org/10.1155/ASP/2006/62831

Received: 15 June 2005

Accepted: 13 August 2006

Published: 29 October 2006

Abstract

We propose channel estimation and direct equalization techniques for transmission over doubly selective channels. The doubly selective channel is approximated using the basis expansion model (BEM). Linear and decision feedback equalizers implemented by time-varying finite impulse response (FIR) filters may then be used to equalize the doubly selective channel, where the time-varying FIR filters are designed according to the BEM. In this sense, the equalizer BEM coefficients are obtained either based on channel estimation or directly. The proposed channel estimation and direct equalization techniques range from pilot-symbol-assisted-modulation- (PSAM-) based techniques to blind and semiblind techniques. In PSAM techniques, pilot symbols are utilized to estimate the channel or directly obtain the equalizer coefficients. The training overhead can be completely eliminated by using blind techniques or reduced by combining training-based techniques with blind techniques resulting in semiblind techniques. Numerical results are conducted to verify the different proposed channel estimation and direct equalization techniques.

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Authors’ Affiliations

(1)
Electrical Engineering Department, United Arab Emirates University
(2)
Faculty of Electrical Engineering, Mathematics, and Computer Science, Delft University of Technology
(3)
ESAT/SCD-SISTA, Katholieke Universiteit Leuven

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Copyright

© Barhumi 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.