Open Access

Low-Complexity Banded Equalizers for OFDM Systems in Doppler Spread Channels

EURASIP Journal on Advances in Signal Processing20062006:067404

https://doi.org/10.1155/ASP/2006/67404

Received: 23 June 2005

Accepted: 30 April 2006

Published: 3 August 2006

Abstract

Recently, several approaches have been proposed for the equalization of orthogonal frequency-division multiplexing (OFDM) signals in challenging high-mobility scenarios. Among them, a minimum mean-squared error (MMSE) block linear equalizer (BLE), based on a band LDL factorization, is particularly attractive for its good tradeoff between performance and complexity. This paper extends this approach towards two directions. First, we boost the BER performance of the BLE by designing a receiver window specially tailored to the band LDL factorization. Second, we design an MMSE block decision-feedback equalizer (BDFE) that can be modified to support receiver windowing. All the proposed banded equalizers share a similar computational complexity, which is linear in the number of subcarriers. Simulation results show that the proposed receiver architectures are effective in reducing the BER performance degradation caused by the intercarrier interference (ICI) generated by time-varying channels. We also consider a basis expansion model (BEM) channel estimation approach, to establish its impact on the BER performance of the proposed banded equalizers.

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Authors’ Affiliations

(1)
Department of Electronic and Information Engineering, University of Perugia
(2)
Department of Electrical Engineering, Faculty of Electrical Engineering, Mathematics, and Computer Science, Delft University of Technology

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Copyright

© Rugini 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.