Challenges and chances for smart rail mobility at mmWave and THz bands from the channels viewpoint

In the new era of “smart rail mobility”, infrastructure, trains, and travelers will be interconnected to achieve optimized mobility, higher safety, and lower costs. In order to realize a seamless high-data rate wireless connectivity, up to dozens of GHz bandwidth is required, and this motivates the exploration of the underutilized millimeter wave (mmWave) as well as the largely unexplored Terahertz (THz) bands. In order to realize the smart rail mobility at mmWave and THz bands, it is critical to gain a thorough understanding of the wireless channels. In this paper, according to the state of the art in research on railway wireless channels, we identify the main technical challenges and the corresponding chances concerning the reference scenario modules, accurate and efficient simulation platform, beamforming strategies, and handover design.