Research Of Symbol Synchronization Technology For DMR Terminal

Now trunking mobile communication system is transferring from analog to digital system. DMR which the ETSI is developing is engaging more and more concentrations from communication organizations and device providers. At the same time, as the development of DSP device, technology of digital signal processing is widely used in communication, which combines all-digital receiver with software radio deeply. This paper simulates and researches the symbol timing synchronization technology of all-digital receiver based on the four levels baseband modulation signal of 4FSK in DMR system. Entirely analyses theory of interpolation which relates to multi-rate signal processing, particularly focuses on Gardner algorithm, non-linear transform timing error estimate that bases on the Maximum Likelihood (ML), maximum average power etc timing recovery algorithm which have widely application recently, puts forward implement and dose system simulation. Validate different algorithm from mapping, BER, timing adjustment, timing jitter performance and structure. Finally, with a view to the existent superframe transmission and DMR protocol's requirement, presents a betterment using timing error estimation and test on hardware. Simulation results show good performance.