ENHANCED PHASE-SHIFTED PILOTS BASED CHANNEL ESTIMATION FOR MIMO-OFDM SYSTEMS WITH VIRTUAL SUBCARRIERS

Generalizing a conventional phase-shifted pilot (PSP) sequences and discrete Fourier Transform (DFT) based channel estimator to MIMO-OFDM systems with virtual subcarriers, this paper presents two enhanced channel estimators applying Wiener interpolation and smoothing. Simulation results show that the proposed schemes can almost eliminate the mean square error floor of the conventional PSP/DFT-based channel estimator and improve the channel estimation accuracy further in some cases. Additionally, the application of a robust channel correlation matrix estimator avoids the complicated measurement of channel statistical properties and thus makes the proposed schemes more feasible in practical systems.