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With the continuous expansion of the mobile user and an endless stream of new communication systems, traditional static spectrum allocation method has been to a large extent to constraint the continued development of the communications industry. Band increasing scarcity of resources, cognitive radio technology as an intelligent dynamic spectrum sharing solutions, has become a hot research. Cognitive radio detection via wireless environment, choose to use idle bands, and real-time monitoring of the use of the band, band shortage can effectively alleviate the premise does not affect the band primary user, take full advantage of each band resources. The context of military applications, cognitive radio receiver system and the receiving end. The article first in engineering applications premise studied spectrum detection technology; then focused to study a variety of communications signal modulation mode identification method, the identification method of a signal modulation method based on the the smooth cycle characteristics of the modulated signal, the method simultaneously applies analog modulation and digital modulation signal. The identification method can be divided into three parts: First cycle spectral density of the algorithm to achieve, through the study and simulation, and ultimately determine the use of the frequency smoothing algorithm; followed by extraction, after the analysis of the shape and characteristics of each cycle of the modulation signal spectrum, extraction domain of f, α domain spectral lines, f domain α domain standard deviation under cyclic spectrum characteristics phasor; Finally, classification and identification, selection of SVM classifier training of a large sample of feature vectors extracted classification thereby completing the identification of the input signal modulation scheme. Finally, in conditions where the SNR is 9dB-13dB, AM, DSB, SSB, BPSK, QPSK, BFSK, QFSK MSK, 16QAM, ASK, ten kinds of common modulation method of the modulation signal and computer simulation experiments, the final experimental results The correct rate of 97.5%, and also prove the effectiveness of the algorithm. In this paper, the study of optical networks based on optical carrier RF system, wireless optical access network with the combination of cognitive radio networks and networking solutions. Cited wireless optical access network can effectively solve the access network bandwidth bottleneck problem in the mobile communication system, and to bring anti-electronic jamming, low-power, low-loss system, easy installation and maintenance advantages. Finally, from the point of view of the system design, gives a complete military cognitive radio receiver system solutions and specific treatment processes. The system is divided into a number of functional modules, and program and technical details of the specific implementation of each module to do a summary description.
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