applied sciences Article Broadband Wireless Communication Systems for Vacuum Tube High-Speed Flying Train Chencheng Qiu 1, Liu Liu 1,* , Botao Han 1, Jiachi Zhang 1, Zheng Li 1 and Tao Zhou 1,2 1 School of Electronic and Information Engineering, Beijing Jiaotong University, Beijing 100044, China;
[email protected] (C.Q.);
[email protected] (B.H.);
[email protected] (J.Z.);
[email protected] (Z.L.);
[email protected] (T.Z.) 2 The Center of National Railway Intelligent Transportation System Engineering and Technology, China Academy of Railway Sciences, Beijing 100081, China * Correspondence:
[email protected]; Tel.: +86-138-1189-3516 Received: 4 January 2020; Accepted: 14 February 2020; Published: 18 February 2020 Abstract: A vactrain (or vacuum tube high-speed flying train) is considered as a novel proposed rail transportation approach in the ultra-high-speed scenario. The maglev train can run with low mechanical friction, low air resistance, and low noise mode at a speed exceeding 1000 km/h inside the vacuum tube regardless of weather conditions. Currently, there is no research on train-to-ground wireless communication system for vactrain. In this paper, we first summarize a list of the unique challenges and opportunities associated with the wireless communication for vactrain, then analyze the bandwidth and Quality of Service (QoS) requirements of vactrain’s train-to-ground communication services quantitatively. To address these challenges and utilize the unique opportunities, a leaky waveguide solution with simple architecture but excellent performance is proposed for wireless coverage for vactrains. The simulation of the leaky waveguide is conducted, and the results show the uniform phase distribution along the horizontal direction of the tube, but also the smooth field distribution at the point far away from the leaky waveguide, which can suppress Doppler frequency shift, indicating that the time-varying frequency-selective fading channel could be approximated as a stationary channel.