Research And Implementation On Key Technologies Of PDT Digital Trunking Base Station

PDT(Police Digital Trunking) standard is a next-generation digital trunking communication standard with independent intellectual property rights of China. It focuses on the future direction of digital radio technology with fast connection, efficient use of spectrum, flexible networking, mainly used in dispatching. The PDT base station is the core component of PDT system. In order to develop PDT system, this thesis deeply discusses some key techniques of the PDT base station.This thesis first analyzes the overseas and domestic research status of digital trunking system, expounds the features and advantages of PDT digital trunking system, topic origin and the thesis structure.Secondly, this thesis analyzes the PDT standard, the three-layer structure of PDT communication protocols, the relationship between layers, and their implementation methods.Thirdly, this thesis conducts the thorough research on the hardware and software requirements of PDT base station, brings forward a scheme of PDT base station circuit. The thesis focuses on the design of heterogeneous architecture which contains both ARM and DSP processor in order to implement the first and the second layer of PDT communication protocols. In addition, emphasis is put on the design and implementation of base station controller — the core component of base station.Then, the thesis analyzes the three functional planes of the PDT system, presents a scheme of PDT base station interconnection, put forward a twin center, centralized exchange and peer-to-peer communication architecture which can effectively reduce the load of switch center, improve response time of transaction. This thesis also uses three different communication protocols, designs different communication interfaces, in order to adapt to the different needs of three functional planes.The PDT base station prototype has passed the IOP test arranged by PDT alliance, and completed interoperability test with a number of mainstream PDT handsets. The result shows that the design of PDT base station in this thesis can meet functional and performance requirements of the PDT standard.