Robust and efficient intercarrier interference mitigation for OFDM systems in time-varying fading channels

Document Type

Article

Publication Date

12-1-2007

Abstract

Due to its spectral efficiency and robustness over multipath channels, orthogonal frequency-division multiplexing (OFDM) has served as one of the major modulation schemes for high-speed communication systems. In the future, wireless OFDM systems are expected to operate at high carrier frequencies, high speed, and high throughput for mobile reception, where fast time-varying fading channels are encountered. Channel variation destroys the orthogonality among the subcarriers and leads to intercarrier interference (ICI). ICI poses a significant limitation on wireless OFDM systems. The aim of this paper is to find an efficient method of providing reliable communications using OFDM in fast time-varying fading channels. It is observed that ICI power arises from a few adjacent subcarriers. This observation motivates us to design low-complexity Q-tap ICI equalizers. To employ these equalizers, channel state information is also required. In this paper, we also design a pilot-aided minimum mean square error (MMSE) channel estimation scheme for a time-varying wide-sense stationary uncorrelated scatters channel model. The MMSE channel estimator utilizes the statistical channel properties to achieve computational efficiency. Simulation results show that our proposed low-complexity ICI suppression scheme, which incorporates the Q-tap equalizer with the MMSE channel estimator, can significantly improve the performance of OFDM systems in fast time-varying fading channels. © 2007 IEEE.

Publication Source (Journal or Book title)

IEEE Transactions on Vehicular Technology

First Page

2517

Last Page

2528

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