Research On Cooperative Spectrum Detection In Cognitive Radio

In recent years, with the continuous progress of wireless communicationtechnology, the demand for wireless communication services is also increasing,spectrum resources are becoming increasingly scarce. However， Fixed spectrumallocation policy currently used result in the great waste of the authorized spectrumresources. To resolve this problem, the cognitive radio technology has been studiedextensively. It uses dynamic spectrum allocation strategy which can effectively improvethe spectrum utilization.In order not to confuse the primary users when access the free unlicensed spectrum,cognitive users must be able to accurately detect the authorized primary user signal’spresence or absence. Spectrum detection technology is the prerequisite and basis for theproperly work of the cognitive network. In this paper, the cooperative spectrum sensingis mainly studied.The paper first introduces the cognitive radio research background, concepts,research status, key technologies, applications, and basic spectrum detection technology,which lay the foundation for the study of cooperative spectrum sensing technology.Then the paper focus on the following two aspects.Firstly, this paper analyzes the insufficient of traditional double-thresholdcooperative spectrum detection，and then proposes a weight-based double-thresholdcooperative spectrum sensing algorithm. The fusion center gives nodes different weightsrelated to their own reputation in order to adjust their influence to the final integrateddecision. Simulation results show that the proposed scheme can not only ensure asmaller communication flow during cooperative sensing，but also have better detectionperformance when there are different channel conditions and the malicious nodes incognitive networks.In addition, in order to reduce the impact of the decline on the performance ofspectrum sensing, based on the traditional hard-merger cooperative spectrum detection，the paper proposes a cluster-based hard-merger cooperative spectrum scheme. Thepaper analyses the relationship between the collaboration of the number of nodes andthe detection performance under the OR integration strategy，and then proposes apartial cooperative nodes search algorithm. The simulation results show that theproposed scheme ensures a smaller channel error rate.