The Research And Design On Digital Interphonebased On DMR Protocol

Currently, the market of short-range wireless communication has been dominated by analog interphone devices. The digitization process of interphone is quite slowly. The relatively high price of digital radio system and the immature application are the root cause of this industry’s slow development. According to the Ministry of industry and information technology of PRC’On the150MHz,400MHz frequency appropriative radio band planning and management" which analog interphone will gradually fade into history, so the research on digital interphone implementation is meaningful.DMR protocol is the latest version of the digital trunking communication standards proposed by European Telecommunications Standards Institute (ETSI) in2007.It applies to civil, conventional and trunking operation mode. Compared to other digital trunking communication standard, DMR protocol products have such features as low cost, easy to develop and excellent performance. This paper designs and implements a digital interphone system based on the DMR protocol. Data communication ability is used to develop an intelligent application to realize a navigation system base on GPS/BDS.This design is based on STM32microcontrollers, HR_C5000baseband chip and AMBE3000vocoder chip to bulid the hardware platform. Digital PLL chip is used to build RF circuit structure. Real-time operating system (μC/OS-III kernel) is used to achieve DMR protocol stack software and application software. USB-to-USART connection plug is used to set up connection between digital interphone (console) and PC. So the console can make PC receive other interphones’(mobile station) location infomation. PC can display mobile station’s location on real-time and control them.Finally, digital radio tester Aeroflex3920is used to give an overall system performance test. As well as the location based software test results is provided. A conclusion is summerized on the DMR protocol-based digital interphone design and a reference is provided for the design of trunking communication system terminals. A reference design for digital interphone system’s location based service application is presented too. An idea is propsed for the development of digitial interphone industry.