Higher frequency band beamforming scheme for high speed train

With the increasing popularity of high speed trains (HSTs) and the traffic forecast for future cellular networks, the need to provide very high data rates using higher frequency bands (HFBs) for train passengers is becoming crucial. In this paper, we present a timer-based beamforming selection algorithm for HST, which exploits the prior knowledge of the position and direction of the HST. A sequential and hierarchical codebook is designed based on the array response vectors and linked to the line-of-sight (LOS) angle-of-arrival/departure base station (BS)-HST link. The effect of velocity feedback errors on the throughput performance was analyzed. The antenna deactivation and the sub-array approaches were considered to mitigate the effect of velocity feedback errors. Evaluation of our proposed beamforming scheme indicates a close performance to the optimal singular value decomposition (SVD) scheme when no velocity feedback error occurs and with the occurrence of velocity feedback errors, the sub-array approach proved to be an efficient way to reduce the effect of the errors.