Research Of DMR System’s Repeater Technology And Design And Development Of Repeater Station Hardware

Compared with the public wireless communication system the private wireless communications system has many advantages, such as calling connect is fast, supporting one-to-many communication and so on, so it is suitable for many fields, especially department dispatching. In recent years, with the rapid development of communication technology, the private wireless communication has also developed sharply. Digital private wireless communication will gradually replace analogue private wireless communication, due to its high spectrum efficiency, strong anti-interference performance, providing data applications, etc. As the latest global open standard for digital radio which the Europe Telecommunication Standards Institute(ETSI) is developing on, DMR protocol has the advantages of highly openness and low cost, etc and received widespread attention in the private wireless communications.This paper studies the DMR system’s repeater technology and the hardware design and development of the transit station. The first the paper introduces the background and development of the private wireless communications, the next the frame structure and repeater mode of DMR system are introduced, then it describes the characteristics of the radio propagation environment and the propagation model, with the coverage scheme of common wireless communication systems, the DMR repeater coverage problem is analyzed and illustrated. Secondly, this paper proposes the design scheme of transit station hardware experiment platform and discusses the feasibility of the scheme, then it designs the forwarding board hardware circuit and its respective interface circuits are described in detail, and the PCB design process of the forwarding board is introduced. Finally, the debugging process of the forwarding board hardware circuit is described, then the paper describes the process of writing and debugging the programs of repeater channel and it gives a experimental platform of transit station baseband. Then the experiment of the transit station baseband transfer on the experimental platform is introduced, including BER test and speech test, and the experimental result is analyzed.This paper also describes the author’s work in the DMR digital radio terminal machine development project based on the SB3500, mainly the overall debugging of baseband module and RF module.