Optimal channel estimation for MIMO/OFDM systems in time-varying wireless channels

We address the problem of time-varying (TV) channel estimation for MIMO/OFDM systems. Firstly, the TV channel is modeled by truncated discrete Fourier bases (DFB) and covers the approximation frames of multiple OFDM symbols. Then, a two-step approach with analytical performance are adopted where in the first step the TV channel is optimally estimated following an minimum mean square error (MMSE) sense in one OFDM symbol. In the second step of the two-step approach, the channel estimates (derived in 1^st step) are further enhance over multiple OFDM symbols by using a novel weighted average approach. Simulation confirms that the proposed approach significantly outperforms the conventional TV channel estimators.