Research Of DMR Repeating And Networking Key Tchnology

In the daily railway transportation and production industry, wireless communication is mainly used to realize the dispatching of the train and the railway personnel. The main features of railway wireless communication is the complex terrain along the railway line, various types of the railway line, and the diversity of the railway operations, especially concluded the wireless voice and data communications of the driver and dispatcher. So, communication exactly between the radios cannot meet the need of railway communication, It is necessary to construct our own wireless radio systems. Because of the traditional intercom have the disadvantages of small capacity, low spectrum utilization, poor anti-interference performance, DMR, with the advantages of low cost, flexible networking, and easy to dispatch, has great application potential.This paper firstly researches the working standard and the transmission principles of DMR air interface, and demonstrates the advantages of DMR railway application combined with the needs of Chinese railway industry. Secondly, the paper ascertains the message transmission principles and the data stack configuration through analyzing the repeater protocol and control methods. Thirdly, proposes the application plan of wireless train dispatching and flat shunting by combining DMR air transmission principle with DMR networking principle. According to Okumura-Hata model, the paper puts forward a method of the planning of DMR communication quarter, and calculates the voice traffic, RF path lose, and RF power. Through analyzing the request of wireless train dispatching and flat shunting, the paper puts forward the DMR network simulation environment. At last, constructs a certain DMR network model and simulates the time delay, data message retransfer, link occupy of DMR network.The results show that, DMR can provide high quality and efficiency of voice and data service for Chinese railway communication. DMR repeating network solves the problem of the communication between different personnel, and have advantages of low cost, low power consumption and easy to realize.