Non-iterative MMSE-based channel estimation for mobile MIMO-OFDM systems

In this paper a non-iterative rectangular-type pilot-aided channel estimation algorithm on mobile multiple input-multiple output (MIMO) orthogonal frequency division multiplexing (OFDM) systems is proposed. After minimum mean square error (MMSE) estimation in time direction, channel interpolation must be performed in frequency direction. Recent DFT-based algorithms, in MIMO-OFDM systems, reduce additive white gaussian noise (AWGN) and Inter-Channel Interference (ICI) iteratively, through time domain low-pass filtering in each iteration. Here, it is shown that extending the algorithm used for OFDM systems to be used for MIMO-OFDM systems causes some frequency shift. The proposed algorithm compensates this shift. Then, the iterations become useless and the complexity reduces considerably. The simulation results show that the proposed algorithm slightly outperforms the iterative algorithm in addition to complexity reduction by eliminating iterations.