A Novel Channel Estimation Scheme for MIMO-OFDM Systems with Virtual Subcarriers

In orthogonal frequency division multiplexing (OFDM) systems, some subcarriers at the borders of the allocated bandwidth are not used for transmission as virtual subcarriers. Because of these subcarriers, some conventional channel estimators are not applicable, especially for multiple input multiple output (MIMO) systems. In this paper, our analysis on the effect of virtual subcarriers is briefly presented based on discrete Fourier transform (DFT) estimator in the delay domain. Then, a novel channel estimation approach, which can recover the dispersive distortion of estimated channel impulse response (CIR) caused by virtual subcarriers, is proposed for MIMO-OFDM systems. The proposed channel estimation does not need to know the path delay and is insensitive to the delay tap number. And it can easy be realized. The simulations demonstrate the effectiveness of the proposed approach in both narrow band and wide band mobile wireless channels.