A Pilot Embedded Scheme for Doubly-Selective MIMO-OFDM Channel Estimation

The multi-input-multi-output (MIMO) orthogonal frequency division multiplexing (OFDM) system is attractive for its high channel capacities and robustness to multipath fading in wireless communications. But the time-variation can destroy the orthogonality between subcarriers which will degrade the performance of the system, so the estimation for time-variant multipath channel is necessary. In this paper, we propose a pilot embedded channel estimation scheme which superimposes periodic pilot sequences with different period on information bearing symbols transmitted by different antenna only assuming that the maximum Doppler frequency is known beforehand. This approach is computationally simple and spectrally efficient as well and the performance can be better than that of Wiener filter method under some conditions. The results of computer simulations are presented and the factors which can affect the performance are analyzed