A New Iterative Doppler-Assisted Channel Estimation Joint With Parallel ICI Cancellation for High-Mobility MIMO-OFDM Systems

In this paper, we propose an iterative channel estimation and intercarrier interference (ICI) cancellation method for highly mobile users in long-term evolution (LTE) systems. The proposed scheme estimates the wireless channel by using pilot symbols, estimates of the data symbols, and Doppler spread information at the receiver. The wireless channel is expressed by weighted time-domain channel interpolation, where the interpolation weights are designed based on the Doppler spread and time-domain channel correlations. The channel estimates are obtained by employing a least-square (LS) method. A simplified parallel interference cancellation (PIC) scheme coupled with decision statistical combining (DSC) is used to cancel the ICI and to improve data symbol detection. These data symbols are then utilized to further refine the channel estimation iteratively. The simulation results show that the performance degradation of the proposed iterative channel estimation and ICI cancellation scheme in a high-mobility environment (e.g., normalized Doppler spread of 0.1), compared with the performance of a system when users are static and perfect channel state information (CSI) is available at the receiver, is minimal.