Research On Dynamic Spectrum Access Technology Of Cognitive Radio

Wireless communication technology is becoming the fastest-growing technologies nowadays.With the continuous development of requirements on communications technology,the demands of emerging wireless services and applications for spectrum resources keep on increasing.However,the existing spectrum regulation policy causes seriously spectrum scarcity because of its static allocation mode.Traditional static spectrum allocation and access methods is not capable of supporting the current and future wireless systems,but dynamic access technology can adapt to the future.Cognitive radio(CR)has the characteristics of providing an opportunists way of utilizing and sharing the spectrum.It can effectively improve the utilization of spectrum,by detecting the spectrum holes and dynamically allocating spectrum resources to the users requiring communication.As a promising technology,cognitive radio is applied to solve current spectrum resource scarcity,where spectrum sensing,spectrum management and spectrum sharing are crucial.In this thesis,the two key technologies of spectrum sensing and spectrum sharing are theoretically studied and analyzed in cognitive radio networks based on existing domestic and foreign research.And the main contents and research innovation work is as follows.On the aspect of spectrum sensing,a cooperative spectrum sensing scheme based on quantized data fusion is proposed in this thesis.And a detection efficiency function is defined to analyze how to find the tradeoff between the performance and overhead in cooperative spectrum sensing.Moreover,we analyze how to adjust the scheme to maximize the detection efficiency according to the specific number of bits for transmission under the conditions of limited communication bandwidth.The numerical results of simulation provide excellent guidance for finding the tradeoff between the performance and the feedback overhead.In terms of spectrum sharing,a truthful multi-unit double auction framework for heterogeneous spectrum in secondary market is proposed.A new spectrum sharing model is studied based on pricing mechanisms of McAfee auction.According to the theoretical analysis,the scheme can satisfy three critical economic properties:truthfulness,individual rationality,and budget balance.Finally,simulation results show that the proposed scheme can achieve better user satisfaction,auction efficiency and spectrum reuse rate for the real communication system.The proposed auction framework is practical and effective.