Radio Wave Propagation Characteristics And Relay Technology In Tunnel

Radio waves propagation in complex electromagnetic environment, such as sea, city center, mountain, tunnel, subway, or objects with high-speed movement, electromagnetic interference, path loss, Multipath effect, Doppler effect, noise interference, and so on, is very complex. Therefore, the wireless communication channel analysis, electromagnetic field intensity coverage in the area has become very important, to ensure that wireless communication is normal in these regions. Relay technology can be useful in these special electromagnetic regions.First, this article introduced a little knowledge of radio wave propagation and wireless communication environment. They are related with relay technology. Then introduced several computational electromagnetics methods, and given the simple comparison.Then use geometrical optical method, research and analysis the electromagnetic propagation characteristics of rectangular tunnel and rectangular hangar tunnel. Hangar tunnel is a promising environmental-friendly tunnel. Normal tunnel and hangar tunnel belongs to the special limited space, in order to ensure the communication can use in these special areas, so we need to study the electromagnetic propagation characteristics and solve the wireless signal coverage problem. This article study electromagnetic field intensity coverage in the rectangular tunnel and rectangular hangar tunnel. Summarized their characteristics in different geometry size, different electromagnetic transmission frequency, different electromagnetic polarization mode, shown there exists very obvious phenomenon of multipath fading. For the first time in China to study electromagnetic propagation characteristics in hangar tunnel, and compiled the related simulation program. It can be used for computer simulation and analysis in rectangular tunnel and rectangular hangar tunnel electromagnetic propagation. Effect of multipath propagation in rectangular tunnel and rectangular hangar tunnel on wireless communication is analyzed.Based on this, relay technology in this special electromagnetic propagation environment has been studied. For the first time to study relay technology in hangar tunnel, and given the analysis and research results. Analyzed the impact of multipath propagation on wireless communication, and Analyzed the communication modes' ability of anti-multipath, anti-interference, anti-noise in the rectangular tunnel and rectangular hangar tunnel.Then introduced the special application of relay in next generation of wireless communications, focused on its application in cooperative communication system, and then discussed some possible breakthrough directions.