Doppler frequency offsets estimation and diversity reception scheme of high speed railway with multiple antennas on separated carriages

In this paper, the challenging problems of severe Doppler effects in High-Speed Railway are considered. We build a cooperative antenna system and propose an algorithm of joint channel estimation and Doppler frequency offset (DFO) estimation based on Ricean channel model. Specifically, we first design a maximum likelihood estimation (MLE) algorithm for DFO, showing that the Doppler estimation can be obtained by estimating moving velocity of the train and the path loss with the exploitation of pilots which are placed inside the frame. We then propose a joint detection algorithm in receiver to exploit multi-antenna diversity gains. Furthermore, we derive the theoretical Crammer Rao bound (CRB) for joint channel estimation and DFO estimation. The steady performance of our system is confirmed by numerical simulations.