标题：Channel measurements and models for high-speed train wireless communication systems in tunnel scenarios: a survey
作者：Liu Yu;Ghazal Ammar;Wang Chengxiang;Ge Xiaohu;Yang Yang;Zhang Yapei
作者机构：[Liu Yu] Shandong University, Shandong Provincial Key Laboratory of Wireless Communication Technologies, Ji'nan, Shandong 250100, China.;[Wang Chengxi 更多
通讯作者地址：[Wang, CX]Shandong Univ, Shandong Prov Key Lab Wireless Commun Technol, Jinan 250100, Shandong, Peoples R China;[Wang, CX]Heriot Watt Univ, Sch Engn & 更多
关键词：5G; high-speed train (HST); tunnel scenario; tunnel channel measurement;; tunnel channel model; non-stationary statistical property
摘要：The rapid developments of high-speed trains (HSTs) introduce new challenges to HST wireless communication systems. Realistic HST channel models play a critical role in designing and evaluating HST communication systems. Due to the length limitation, bounding of tunnel itself, and waveguide effect, channel characteristics in tunnel scenarios are very different from those in other HST scenarios. Therefore, accurate tunnel channel models considering both large-scale and small-scale fading characteristics are essential for HST communication systems. Moreover, certain characteristics of tunnel channels have not been investigated sufficiently. This article provides a comprehensive review of the measurement campaigns in tunnels and presents some tunnel channel models using various modeling methods. Finally, future directions in HST tunnel channel measurements and modeling are discussed.