Research And Design On Integrated Platform Of Cognitive Frequency Hopping System

For the challenge faced by traditional frequency hopping communication system, cognitive radio is thoughtfully combined with the traditional frequency hopping and developed into a new area of technology—Cognitive Frequency Hopping which real-time spectrum sensing as a basement, dynamic spectrum allocation as a process and reasonable spectrum management as a result. It is considered to be one of the effective solution of predicaments of traditional frequency hopping system. In this thesis, the integrated platform of cognitive frequency hopping system is designed and implemented, and the conventional spectrum estimating broadband sensing algorithm is validated on the base of the dexterity spectrum display technique of the platform.First, this thesis analyzes the background, significance and application of frequency hopping communication system. The predicaments of traditional frequency hopping system are described, such as increasingly crowded spectrum resource; the needed of effectively using of spectrum; the fact that existing fixed frequency hopping system couldn’t meet the high dynamic and complex mutations of electromagnetic environment; the increasing threat of many types of strong interference traditional aiming at frequency hopping system in harsh environments. Thus, a concept of cognitive frequency hopping system is leaded out.Secondly, an introduction of the cognitive radio and frequency hopping communication system is provided. In addition, some advantages of the system are analyzed;Thirdly, a radio frequency front end of cognitive communication, an intermediate frequency processing module, a spectrum sensing module and an integration platform of display are designed and implemented based on the theories combined with the spectrum sensing and communication in cognitive frequency hopping system;Fourthly, a dexterous design with reconfigurable intermediate frequency and frequency resolution is implemented by making use of the theories of the band-pass sampling theorem, quadrature demodulator and periodogram spectrum estimation. Detailed flowcharts of digital signal processing and a measured spectrogram are revealed later;Finally, based on the integration platform and dexterous spectrum display, the technique of the wideband spectrum sensing technology used in cognitive frequency hopping system is researched. The chosen sensing algorithm based on a conventional spectrum estimation method is used to sense the multisource interference. It can be seen form the theoretical analysis, simulations and measurements that the sensing algorithm meets the demand of the accurate analysis of the trends in cognitive frequency hopping systems.