Research Of Digital Trunking Communication Protocol DMR Channel Code And Decode Technology

Radio is an important application field of special mobile communication system, which can play an incomparable role comparing with other mobile communication equipment in many field such as, in the transportation, in public safety, especially in dealing with natural disasters emergency when public mobile communication system infrastructure have been severely disrupted, because it can be performed quickly call in the conditions of no center node and non-infrastructure.However, there are several disadvantages limiting the application of radio in analog radio, such as low frequency spectrum utilization rate, limited transmission distance is and low voice quality. Therefore, the domestic and foreign related departments and enterprises are committed to formulate standard of digital radio and development the digital radio.DMR (Digital Mobile Radio) is the mainstream digital radio protocol, which released in2007by the European Telecommunications Standards Institute. At present, some enterprises have developed digital radio based on DMR protocol and began to sell in foreign countries. But at home, the development of digital radio is at the start stage, only a handful of radio enterprises are under development and testing. The topic of this paper is derived from one of the enterprises’actual project which will be completed the development of digital radio based on DMR protocol.First of all, this paper introduced the key technology and parameters of the indicators in DMR protocol from physical layer, data link layer and control layer. Secondly, this paper introduced various channel code’ characteristics and principle of coding and decoding, which is used in DMR protocol. Next, this paper designed and simulated some coding and decoding algorithms of various channel code, at the same time, it selected the traditional digital communication system simulation model to simulate the decoding algorithms’ error correcting performance so that. And, the results of simulation shows that these decoding algorithms compared to no coding situation obtained certain coding gain and validation of these decoding algorithms is correct. At the same time, the paper analyzed and summed up the application of channel code in the DMR system voice and data services, besides, it simulated the performance of two kind of business. Finally, we focus on BPTC (196,96), because of its DMR system most widely used, so the decoding error correction performance will directly influence the quality of communication in DMR system. BPTC (196,96) belongs to Turbo product code. In order to obtain the optimum error correction performance, it can be decoded in soft decision decoding. But this paper’s research project uses the hardware platform for the ZSP400which the main frequency is96M, so the time expense of iterative decoding is more than the burst time in DMR on it. Therefore this paper does not use iterative decoding algorithm. Nevertheless, it is a good way to decode the BPTC (196,96) using the hard decision decoding algebra method, so this paper used feasible degree this definition in soft decision to solve defects of the hard decision decoding algebra, which enhanced the error correcting capability and easily be carried out in ZSP400.