An Interpolation Based Channel Estimation Method for MIMO OFDM Systems

This paper proposes a novel channel estimation method to further improve the performance of the optimal pilot sequences in multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) systems. We first assume that the virtual pilot tones superimposed at the data locations over the specific sub-carriers are transmitted from all transmit antennas. We then obtain the virtual received pilot signals at the corresponding locations at the receive antennas by interpolation in the time domain. Finally, the channel parameters are obtained from the combination of the virtual and real received pilot signals over one OFDM symbol based on the least squares (LS) channel estimation. Simulation results show that the proposed channel estimation method provides much better performance than the previous method for the optimal pilot sequences over multiple OFDM symbols, especially in fast time- varying channels.