Pilot-symbol aided channel estimation in spatially correlated multiuser MIMO-OFDM channels

We address pilot-symbol aided up-link channel estimation for spatially correlated multiuser MIMO-OFDM systems. A novel pilot-symbol pattern is firstly proposed for this multiuser system in order to overcome the interference from the multiuser multi-antennas. Based on these periodically inserted pilot symbols, the channel responses for the entire OFDM data sequence is reconstructed by using the maximum a posteriori probability (MAP) estimation algorithm, exploiting channel correlation in the time, frequency and space domains, which are obtained from a time-variant frequency-selective Rayleigh fading channel model with multiple clusters and complex direction of arrival (DOA). Results demonstrated that system performance can be greatly improved by considering spatial correlation in MIMO-OFDM systems with the designed pilot sequences and proposed 3D filter.