Railway Tunnel Coverage Solutions For Research

All tunnels have complex cross section with circular, rectangle, arch, ellipse shape, In accordance with the length of the tunnel is divided into short, medium length of the tunnel, long tunnel. Different types of tunnels of different lengths during wireless coverage, they will naturally take a different solution. Therefore, it is importance to study on propagation characteristic of electromagnetic wave and solution of different lengths tunnel coverage in a tunnel with complex cross section and other problems, which have useful meaning and reality value to perfect tunnel wireless propagation theory and to guide the research on tunnel mobile communication system.This dissertation mainly studies basic theory of electromagnetic wave propagation in tunnel, put forward a variety of wireless coverage solutions for the tunnel. Main conclusions and innovative work are followed as:The tunnel filled with air is dielectric tube waveguide with loss in which natural propagation characteristic of electromagnetic wave is researched systematically. The dissertation systematically discusses the electromagnetic transmission characteristics according to "wave-mode matching theory" about the common rail arch shape tunnel.The dissertation use a ray-tracing/image approach, which used to apply to indoor wireless environments, to analyze the radio wave propagation characteristics in tunnel environments, and systematically discusses the primary principle of this approach,by using it to analyse the wireless propagation characteristic of tunnel.The dissertation collate and study the source selection, antenna pattern of distribution involved in tunnel coverage, put forward different solutions to the typical length of the tunnel.