POWER DELAY PROFILE ESTIMATION TECHNIQUE FOR LMMSE CHANNEL ESTIMATOR OF MIMO-OFDM SYSTEM

A multiple-input multiple-output (MIMO) communication system combined with the orthogonal frequency division multiplexing (OFDM) modulation technique can achieve reliable high data rate transmission over broadband wireless channels. But the performance gain depends heavily on accurate channel estimation. In linear-minimum-mean-Square error (LMMSE) channel estimation for multicarrier system, one needs to know the channel statistics. We propose a power delay profile (PDP) estimation technique to obtain the frequency domain channel statistics at the receiver. The pilot symbols of all transmit antenna ports are used in estimating the PDP. The estimated PDP is used to generate the LMMSE filter Coefficients for data-subcarrier channel estimation. The distortions caused by null subcarriers and an insufficient number of samples for PDP estimation are also considered. The proposed technique effectively reduces the distortions for accurate PDP estimation. Simulation results show that the performance of LMMSE channel estimation using the proposed PDP estimate approaches that of Wiener filtering due to the mitigation of distortion effects