The Subway Wireless Communication System Electromagnetic Interference Analysis And Solution Research

Wireless communication systems are widely used in subway communication system,includes800MHZ wireless trunking communication system, civil mobile communicationaccess system (2g,3g,4g communication system, and CMMB DTV system), the police350MHz analog/digital trunked radio communication system, and the train-ground wirelesscommunication network et. There are many kinds of wireless communication systemwhich has large spectrum width in the metro communication system. For this reason,electromagnetic interference becomes a big problem. Therefore, according to theexperience of the construction of domestic subway wireless communication system,analysis of electromagnetic interference between wireless communication systems is moreand more important.Firstly, this thesis illustrates each wireless communication system in metrocommunication system and the current situation of wireless electromagnetic environment.Secondly, the internal interference in wireless system and interference between wirelesssystems are analyzed. On this basis, we use the certainty of mathematics calculation to putforward technical measures and engineering measures for anti-interference, like improvethe system isolation, use frequency hopping technology, and a reasonable choice of thewireless coverage, increase frequency protection zone, limiting device parameters and aseries of methods. Finally, develop test program for field testing, and analyze theinterference between wireless communication systems in the subway communicationsystem. It verifies the correctness and feasibility of this anti-jamming solution. Accordingto the conclusion of the study, using CAD software drawing reasonable layout ofantenna/leakage cable and draw the relevant engineering design drawings (see Figure4-3~Figure4-11). These achievements will help the design work of communication systemin metro.