Pilot symbol aided MAP-based 3D channel estimation for multi-user MIMO-OFDM systems

This paper describes a novel pilot symbol aided up-link channel estimation scheme for a multi-user MIMO-OFDM system. A novel pilot-symbol pattern is proposed in order to overcome the interference from the multiple antennas of each user. Based on these periodically inserted pilot symbols, the channel state information (CSI) for each entire OFDM data sequence is reconstructed by using the maximum a-posteriori probability (MAP) estimation algorithm. The MAP estimation algorithm exploits channel correlations in time, frequency and space domains, which are obtained from a frequency-selective and time-variant Rayleigh fading channel model with multiple clusters and a defined complex direction of arrival (DOA). Simulation results demonstrate that it achieves almost the same performance as the ideal case by using the MAP-based estimation scheme with the well designed pilot-symbol pattern. Moreover, this model-based estimation scheme is also robust to errors in the estimation of its parameters. It will become one of the strong candidates for use in next generation mobile communication systems.