Study Of Direct Mode Digital Two-Way Radio Base DMR

According to the scope of its service to points, mobile communication system can be divided into professional mobile communication and public mobile communication, Two-way radio is dedicated hand-held device of professional mobile communication systems, and widely used in various fields of social production. It will be widely used in long-term future for that its position on the market is different from other wireless mobile communication tools such as cell phone and can not be replaced, while the characteristics of communication establishment speed and one call mass response. Currently, the field of domestic conventional Two-way radio remains basically in the stage of analog communication technology. Obviously, as people requirements increase on the Two-way radio's performance, a sort of high mobility, no center and point to point digital Two-way radio will become an urgent requirement. In addition, in order to promote the development of digital two-way radio in China, the National Radio Authority published related technical indexes in September 2007.DMR communication system protocol is the latest professional digital mobile communications standard, which is proposed by the ETSI (European Telecommunications Standards Institute). Compared with two mature digital standards, TETRA and iDEN, the DMR product has many advantages such as low cost, simple technology, and the supports of the transition from analog to digital, etc. As DMR is not yet fully formed, follow-up research have significant value.Firstly, this paper carries out analysis and research on the DMR protocol, especially its air interface and voice coding techniques. On this basis, according to the DMR protocol model, develops a Time Division Duplex(TDD) communication protocol program. And then, hardware circuit program of Direct Mode digital two-way radio is designed according to communication protocol program. In this program, CC1101 is selected as the main chip in the RF module, MSP430F149 (MCU) which can reduce power consumption is used for the micro-controller chip, and low-rate voice and high-definition audio codec chip AMBE-1000 (domestic) is chosen for voice processing. Then, the way of the top-down is used for software design of the system, the combination of hierarchical and modularization programming idea is used for architecture design of programming, sub-modules of software architecture and then complete the preparation of the code from bottom to top layer by layer. Finally, the debugging process of hardware and software is introduced.The Direct Mode digital Two-way radio which this paper studied is the first implementation stage in DMR protocol. It's R&D work on Direct Mode mobile terminal, which works in the absence of infrastructure with reciprocity. Full-duplex voice communication and high mobility are realized from the viewpoint of low power consumption and low cost. Moreover, this paper provides a research approach for the terminal design which is to achieve easy, reliable, high-performance voice communication.