The Research Of Coherent Receiver In TETRA Digital Trunked Communication System

TETRA digital trunked communication system is well-developed around the world.Compared with the cellular mobile communication system, It has the characteristics of fastcall set-up, high reliability, high quality of voice service and high spectrum utilization. Inrecent years, it has played an important role in the field of professional communication suchas the field in the government, army, public security, railway, civil aviation. Therefore, theresearch of our country independent intellectual property rights of digital trunkedcommunication system is urgent.This paper focuses on the study of the coherent receiver in TETRA digital trunkedcommunication system. The non-coherent receiver has been adopted at present in thephysical layer of the system. Coherent receiver performs better than non-coherent receiverin the static receiving. When non-coherent demodulation is used, it will lead to pairs ofelement loss if there is mistake, then, non-coherent demodulation has3dB SNR loss thancoherent. Besides, coherent receiver has the strong anti-Doppler shift ability. It is easy toget a local carrier that is strictly synchronized with the transmitter and has more precisionwith the development of the soft radio. From the above, it has the important practicalsignificance to research in the coherent receiver for the TETRA digital trunkedcommunication system.After introducing the research of the related technology in the TETRA digital trunkedcommunication system, the paper focuses on the modular design of coherent receiver, onthe basis of the design, the paper researches the key technology of the digital front-end,then it proposes the key algorithm of the coherent receiver and simulates the algorithm.Finally, the paper provides the implementation method of key module based on the FPGA.