Efficient Doppler mitigation for high-speed rail communications

Since the high-speed rail (HSR) communications are suffering from the huge Doppler shift, an efficient Doppler mitigation method is proposed in this paper. The proposed method mainly concerns about the mitigation of Doppler shift in OFDM based systems, especially for the case of employing mmWave with very high mobility. The proposed method can be used for both downlink and uplink of the system and it is quite robust to the time-varying mobility. Furthermore, the pilot-aided channel estimation for Doppler compensation is not necessary in most of the cases, which indicates the pilot density in time-domain can be reduced. Simulation results show that by using the proposed method, the residual Doppler shift can be compressed to 0 Hz with the probability of 90%.