Towards smart rail mobility at the mmWave and THz bands: Challenges, solutions,and future directions

• 来源期刊: 中国科学基金（英文版）
• 年，卷（期）: 2020,（1）
• 页码范围: 56-80
• 页数: 25页
• 语种: 英文
• DOI: 10.16262/j.cnki.1005-0841.2020.01.002

摘要

In the vision of "smart rail mobility",a seamless high-data-rate wireless connectivity with up to dozens of GHz bandwidth will be required.This forms a strong motivation for exploring the underutilized millimeter wave (mmWave) and Terahertz (THz) bands.In this paper,we identify the main challenges and present the state-of-the-art solutions towards the realization of smart rail mobility.In order to cope with the challenge of involving the railway features in the channel models,we define and reconstruct the complete version and the concise version of the reference scenario modules for mmWave and THz railway channels.Simulations in the complete version of the scenarios reflect the influence of railway objects in detail;based on raytracing simulations in the concise version of the scenarios,two mmWave railway channel models are established and validated by measurements.Moreover,in order to tackle the challenge of heavy computing workload,we develop an open-access high performance ray-tracing platform—CloudRT.Last but not least,the challenges raised by the mmWave directional network under high mobility are overcome by our solutions concerning the handover scheme,random access procedure,and beamforming strategies.By integrating the key enabling technologies presented in this paper,we prototype the mobile hotspot network (MHN) system which realizes 1.25 Gbps downlink data throughput in a subway line with the train speed of 80 km/h.Future directions towards the full version of the smart rail mobility are pointed out as well.