Virtual Subcarrier Aided Channel Estimation Schemes for Tracking Rapid Time Variant Channels in IEEE 802.11p Systems

This paper investigates the channel estimation schemes for tracking rapid time variant channels in IEEE 802. 11p systems. To overcome the problems of the existing preamble based channel estimation, various data-pilot aided (DPA) algorithms have been developed. However, their performance is not sufficient to meet the advanced V2X use cases. In this paper, we propose a novel two step channel estimation scheme which outperforms the conventional DPA designs. For the first step, we develop an enhanced time-domain reliability test and frequency domain interpolation scheme by exploiting the Euclidean distance between the received signals and constellation points, and the channel information in the virtual subcarriers to improve the prediction accuracy at high signal-to-noise ratio (SNR). In the second step, we attenuate the noise components from the estimated channel frequency responses in the previous step to address the low SNR performance gain. To this end, we adopt the time domain least square estimation strategy. The proposed scheme exhibits dramatic performance gain over the SNR with marginal complexity increase compared to the conventional DPA algorithms. Finally, simulation results verify the efficiency of the proposed scheme.