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 2×1D 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 2×1D 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 2×1D scheme and more advanced ICI cancellation schemes, since it provides more accurate channel estimates in high Doppler spread conditions.