Design of Implementation-Efficient Channel Estimation Filters for Wireless Transmission of OFDM Signal

Abstract

The detection performance of coherent OFDM receiver significantly depends on the accuracy of channel estimation. The accuracy of channel estimation can ve improved by proprly post-processing the channel estimate using so-called chennel estimation filter (CEF). Minimum mean-square error(MMSE) filtre is known optimum as the CEF, but it may not be practical due to its implemetation complexity. We consider the use of a reduced-complexity CEF whose tap coefficient is real valued and smmetricallty 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 confition. Numerical reesults show that the porposed RSW CEF can provide channel estimation performance coparrable to that of linear MMSE filter, while sifnificantly 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.