Concepts on Train-to-Ground Wireless Communication System for Hyperloop: Channel, Network Architecture, and Resource Management

• Published in: Energies (Basel) Vol. 13; no. 17; p. 4309
• Main Authors: Zhang, Jiachi, Liu, Liu, Han, Botao, Li, Zheng, Zhou, Tao, Wang, Kai, Wang, Dong, Ai, Bo
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 01.09.2020
• Subjects: Algorithms; Antennas; Communications systems; Computer architecture; Computer simulation; Doppler effect; Electron tubes; Expenditures; Graph theory; hyperloop; Latency; Mapping; Multiplexing; network architecture; Network latency; Noise; Resource management; Simulation; Traffic; train-to-ground communication; Velocity; Waveguides; wireless channel; Wireless communication systems; Wireless communications; Wireless networks; China
• ISSN: 1996-1073; 1996-1073
• DOI: 10.3390/en13174309

Hyperloop is envisioned as a novel transportation way with merits of ultra-high velocity and great traveling comforts. In this paper, we present some concepts on the key technologies dedicated to the train-to-ground communication system based on some prevailing fifth-generation communication (5G) technologies from three aspects: wireless channel, network architecture, and resource management. First, we characterize the wireless channel of the distributed antenna system (DAS) using the propagation-graph channel modelling theory. Simulation reveals that a drastic Doppler shift variation appears when crossing the trackside antenna. Hence, the leaky waveguide system is a promising way to provide a stable receiving signal. In this regard, the radio coverage is briefly estimated. Second, a cloud architecture is utilized to integrate several successive trackside leaky waveguides into a logical cell to reduce the handover frequency. Moreover, based on a many-to-many mapping relationship between distributed units (DUs) and centralized units (CUs), a novel access network architecture is proposed to reduce the inevitable handover cost by using the graph theory. Simulation results show that this scheme can yield a low handover cost. Then, with regards to the ultra-reliable and low latency communication (uRLLC) traffic, a physical resource block (PRB) multiplexing scheme considering the latency requirements of each traffic type is exploited. Simulation presents that this scheme can maximize the throughput of non-critical mission communication services while guaranteeing the requirements of uRLLC traffic. Finally, in terms of the non-critical mission communication services, two cache-based resource management strategies are proposed to boost the throughput and reduce the midhaul link burden by pre-fetching and post-uploading schemes. Simulation demonstrates that the cache-based schemes can boost the throughput dramatically.