Protocol Research And Hardware Implementation Of Digital Radio Based On DMR

The mobile communication consist of two major research areas,the one is public mobile communication which has been an unprecedented development,and the other is professional mobile communication that is still basically in its infancy. The traditional analog radio has been unable to meet the needs of the market. And digital trunking communication system has some advantages, such as a group call, fast connection time, rich business, and confidentiality.In order to catch up with the pace of global private network digitization reforms, China has also begun to study private network digital trunking communication system and introduced the related standards.Since the DMR uses TDMA dual slot, has high spectral efficiency, and backward compatibility is good, there is no advantage of technical barriers, etc., so the development of digital radio DMR terminal will have great significance.Firstly, the thesis carefully study the DMR protocol, including its hierarchical model, frame structure, timing relationships, business type, etc. Secondly, it focuses on underlying key technologies that are4FSK modulation and demodulation and BPTC channel codec.4FSK can be divided into two parts, including the baseband signal processing and IF quadrature modulation and demodulation. The paper gives a detailed algorithm derivation and design diagram, and the algorithm is implemented with software.Then DMR digital radio verification system is proposed based on windows and usrp.In this paper, the system consists of three parts PC+USRP+AMBE1000. And it gives a detailed description of each module functions and interface design, focuses on UHD and USRP1software radio development platform and restructures USRP interface function API.Finally, It completed the function and call test of the verification system. And the test results show that the verification system meets the DMR protocol standard, and complete digital radio single call and group call feature. Further, by comparison with commercial radio pd780, the tested further verify the accuracy of the call control system and time slot structure.The system uses a universal software radio processing platform, which facilitates the development of each module, is easy to increase the variety of features and has software portability. So it is a better digital radio development programs.