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Design of Implementation-Efficient Channel Estimation Filters for Wireless Transmission of OFDM Signal
Jae-Ho RYU Yong-Hwan LEE
IEICE TRANSACTIONS on Communications
Publication Date: 2003/11/01
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Wireless Communication Technology
OFDM, coherent detection, channel estimation, adaptive CEF, timing offset,
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The detection performance of coherent OFDM receivers significantly depends on the accuracy of channel estimation. The accuracy of channel estimation can be improved by properly post-processing the channel estimate using a so-called channel estimation filter (CEF). Minimum mean-squared error (MMSE) filter is known optimum as the CEF, but it may not be practical due to its implementation complexity. We consider the use of a reduced-complexity CEF whose tap coefficient is real-valued and symmetrically weighted (RSW). The optimum RSW CEF is analytically designed using the SNR and multi-path intensity profile of the channel. For further improvement, we also propose a method to adapt the coefficient of the RSW CEF to the channel condition. Numerical results show that the proposed RSW CEF can provide channel estimation performance comparable to that of linear MMSE filter, while significantly reducing the computational complexity. In addition, the proposed RSW CEF can provide performance robust to unknown timing offset with a fractional dB loss compared to the optimum one.