Realization Of Hand-held Terminal Based On Dpmr Protocol

The public wireless communication and private wireless communicationare two major application areas of wireless communication. With thedevelopment of digital technology, its advantage is more and more obvious.So, private wireless communication will inevitably go into the digital age asthe public wireless communication. At present in China, the research in digitalprivate wireless communication are beginning to develop but still in the firststage.According to the digital trend of private wireless communication, theEuropean Telecommunications Standards Institute (ETSI) puted forward DMRand DPMR protocol. Due to the low prices, we choose the DPMR protocol,and based on the protocol, we designed the whole system structure and alsorealized it.There are five layers in the system structure, and this paper layeredexplained the implementation principle in detail. Acording to the introductionof the FreeRTOS operating system, we further discussed the realization ofeach layer and the way of communication between each layer, and finallyrealized the whole system. Beside, we tested the system and showed the test results. The test results show that the hand-held terminals can meet thecorresponding requirements.Domestic and overseas all had just entered the radio module changingstage. So it has not yet been determined that which communication protocolwill be used in the terminal. Though lacking of the reference about theradiophone software and hardware realization, we also designed and realizedthe DPMR system. The innovations in this paper are the system architecturemodel, the data and voice interactive process and the introduction of theFreeRTOS operation system which never be used before in the interphone.