On the design of ML channel estimation scheme for SDM OFDM systems

This paper presents the channel estimation and equalization schemes for spatial division multiplexing (SDM) OFDM systems. The channel impulse/frequency response is probed utilizing the pilots embedded within the OFDM symbols. The pilots are arranged diagonally in spatial and temporal domain. The maximum likelihood estimation algorithm is then applied to SDM OFDM sub-carriers channel estimation. Computer simulations are conducted to evaluate the performance of the channel estimation scheme for different combinations of transmit and receive antennas in time-varying frequency selective fading channels suggested in 3GPP specifications. It is shown by the simulation results that the channel estimation scheme perform well in severe multipath fading channels.