Pilot based LMMSE channel estimation for Multi-User MIMO- OFDM systems with power delay profile

In this paper, a power delay profile estimation technique for linear minimum mean square error channel estimator of Multi-User multiple-input multiple-output Orthogonal Frequency Division Multiplexing systems is proposed. For practical applications, the proposed technique uses only the pilot symbols of all the transmit antenna ports to estimate the power delay profile with low computational complexity. The proposed technique effectively estimates the distortions caused by power delay profile. The performance is measured using the mean squared error between the actual and the estimated frequency response. The performance is compared to the performance of a 2×1 dimensional Wiener interpolator, which consistently yields the lowest mean square error but also the highest complexity. It is shown that the performance of this estimator for channel estimation purpose is close to the 2×1D Wiener filter at 120 km/h for different signal-to-noise ratios.