Influence of Wall-Attached Antenna Distance on Channel in Tunnel Scenario

The transformation of high-speed railway is moving toward intelligence, information technology, and digitalization. Railway 5G dedicated mobile communication (5G-R) system has become the first choice for high-speed railway communication systems and an important guarantee for the safe operation of high-speed railways. Tunnels are one of the typical railway scenarios, and the deployment of a reliable and stable 5G-R system is the guarantee for the safe operation of future intelligent high-speed railways. However, in an actual tunnel, the electric cables erected on the upper wall of the tunnel and the smooth passage of trains will limit the installation position of the antenna. Generally, the transmitting antenna is selected to be installed near the side wall. This paper takes the tunnel as the research scenario, and uses ray tracing technology to simulate the wireless channel characteristics of the transmitting antenna at different installation positions on the side wall of the tunnel in the 2.1 GHz frequency band, including received power, K factor and Root-Mean-Square Delay Spread (RMS DS), which can be used for this scenario. The construction optimization and deep coverage of the railway 5G network provide a theoretical basis to deploy a more stable and reliable 5G mobile communication system.