Intercarrier Interference-Aware Pilot-Aided Channel Estimation in OFDM Systems

Linear pilot-aided channel estimation in orthogonal-frequency division multiplexing systems is carried out optimally via 2D Wiener filters. The standard approach employed in conventional receivers is based on cascaded 2x1D Wiener filtering. In doing so, suboptimal performance is tolerated for the sake of lower complexity. By means of the 2D+1D filtering scheme proposed in this paper, the performance of cascaded filtering is enhanced while maintaining the low complexity of the 2x1D approach. A theoretical analysis of different cascaded Wiener filtering approaches is provided, and the approaches are compared. Furthermore, the effect of Doppler-induced intercarrier interference (ICI) is taken into account for the calculation of the mean-squared error (MSE) of the different channel estimation schemes. Additionally, practical real-time adaptive versions of these schemes are demonstrated. Results from full link-level simulations with respect to the digital video broadcasting standard for satellite services to handheld devices are presented. The proposed 2D+1D filtering scheme shows enhanced MSE and bit error rate performance than both conventional 2x1D scheme and more advanced ICI cancellation schemes, since it provides more accurate channel estimates in high Doppler spread conditions.