Research On DMR Baseband System Based On Software Radio

The public wireless communication and private wireless communication are two major application areas of wireless communication. The public wireless communication has been digitized in China, but private wireless communication is still at the simulation stage. With the continuous development of wireless communication technologies, European Telecommunication Standards Institute introduced the special wireless communication standard:DMR (Digital Mobile Radio) in 2005. ETSI has the DMR standard changed several times, so that the standard has been improved gradually. The DMR standard has many advantages, such as low product cost, simple technologies, etc. The DMR standard supports the transition from analog to digital, and can offer an advanced communication performance compling with the ETSI technology standard 102-361. Because the DMR standard is the latest one, all of it is still in the initial stage of development.Firstly, the paper introduces the key technologies used to the DMR system in development process, such as software radio technology, multi-rate signal processing technology, etc; And related algorithms, for example CP4FSK modulation and demodulation algorithms, the carrier recovery algorithm based on the gradient, etc. These technologies and algorithms provide the theoretical guidance for further engineering realization.Then, the author puts forward his own implementation schemes on the square-root raise cosine filter, CP4FSK modulation and demodulation algorithms, digital broadband Intermediate frequency design etc, through the combination of Matlab and DSP; And proposes carrier recovery design scheme in the light of DMR system with the double gradient algorithm; And analyzes the ber performance of the modulation and demodulation algorithms. Simulation results show that, demodulation algorithm has the strong anti-interference ability.Finally, the paper puts forward a design scheme of the DMR system based on software radio, which provides a feasible scheme for the implementation of digital radio.