Research And Applications Of The Wireless Spread Spectrum In Railroad Tunnel

The working circumstance is severe in modern railroad tunnel construction and the mine pit mining work. Being insufficient efficient directions on the spot, potential dangers can not be foreseen and efficient conduction can not be afforded。 By the request of sixteenth bureau of China railway working on the Yichang, Hubei—Wan Zhou, Sichuan sector, we have designed and installed the wireless network monitoring system。Meanwhile, we have done much work on the microwave propagation characteristic in tunnel and obtained some important results. In tunnel, traditional multi-path effect reversely becomes an efficient way to enhance the signal intensity and make the signal transmit along the abrupts. The theory analyses help us to make scientific design and choose appropriate equipment and solve some problems in project. The tests that are appraised by the commanders on the spot are satisfactory: the pictures are clear and the voice is fluent. These tests in turn verified the research on the microwave in tunnel.For the complex circumstances, it is more difficult to research in tunnel than in free space. First, this paper begins the study under the house environment that has been proceeded for many years and matured to some extent, which can offer the necessary simulation environment for that in tunnel, then this paper places emphasis on the microwave characteristic in tunnel. The analyses center around rectangular tunnel model including the problems in the tunnel microwave simulation process by means of ray tracing method. This thesis has put forward the principle followed by reflected waves that is Tent Principle, which has also...