Combined frequency and time domain channel estimation in mobile MIMO-OFDM systems

This paper proposes a combined frequency and time domain channel estimation method for MIMO OFDM systems. Initial channel estimation is performed by first estimating the channel response in frequency domain, exploiting a set of dedicated pilot carriers, followed by an interpolation step. In order to reduce the interpolation error and improve the bit error rate performance, we propose to refine the channel estimates in time domain using the equalized signal from the frequency domain processing. Simulations have been carried out using the spatial channel model proposed under the 3GPP framework. The proposed method has been tested in a wide range of mobile speeds in conjunction with several standard MIMO equalizers. The results show that the proposed estimator outperforms widely used time and frequency domain channel estimation approaches.