On the implementation of DMR system based on SDR structure

DMR is a digital trunking communication protocol proposed by ETSI which has predictable doubling of capacity in existing 12.5 kHz licensed channels and delivers backwards spectrum compatibility with legacy analog systems. The DMR system implemented in this paper is based on SDR (Software Defined Radio) structure, which components that have been implemented in hardware (e.g. filters, modulator/demodulator, synchronization, etc.) are implemented by means of software on a central processor. The system architecture and baseband process are emphasized. The system and modules in the system can be integrated as a wave component library to other communication system, meanwhile all functions, modes and applications can be configured, reconfigured and upgraded in the field with new capabilities by software. The SDR based DMR system implemented in this paper communicates well with commercial terminals which proves the accuracy of signaling processing and compatibility with existing terminals. The system holds great significance in multi-modes system research and digital trunking communication system substitute for current analog trunking system.