DCT-based channel estimation for OFDM systems

In this paper, based on the property of channel frequency response and the concept of interpolation in transform domain, we propose two discrete cosine transform (DCT)-based pilot-symbol-aided channel estimators, which can mitigate the aliasing error and high-frequency distortion of the direct discrete Fourier transform (DFT)-based channel estimators when the multipath fading channels have non-sample-spaced path delays. Both proposed estimators outperform the conventional DFT-based channel estimators. Of these two DCT-based estimators, one has its performance close to MMSE estimator, while the other one has the advantage of easy implementation with a little performance degradation. Furthermore, in implementation, the DCT-based estimators have the advantages of utilizing mature fast DCT algorithms and architectures, which is favorable to matrix-based channel estimators.