Pilot Aided 3D Channel Estimation for MIMO-OFDM Systems

Considering three dimensional (3D) channel with elevation effect, this paper addresses pilot spacing design in frequency, time and spatial domains for orthogonal frequency division multiplexing (OFDM) systems with multiple antennas. Employing the channel spatial correlation between transmit antennas, pilot overhead can be reduced substantially without estimation accuracy loss. On the other hand, the accuracy of pilot aided channel estimation (PACE) can be improved. This paper also verifies the performance of cascaded lower-dimensional Wiener filters in mean square error (MSE) sense. Numerical results show that the channel estimation in frequency-space domain is undecomposable.