Research On Spectrum Sensing Algorithm Based On Joint Channel State Estimation

With the growing scarcity of radio spectrum resources,cognitive radio technology can use the vacant spectrum and perform opportunistic transmissions in the premise of not affecting the normal work of the authorized users,which effectively improves the spectrum utilization.Therefore,in recent years,the cognitive radio technology has been widely concerned and viewed as the alternative technology of next generation of mobile communication.Spectrum sensing is the core of the cognitive radio technology.The analysis shows that,in bad electromagnetic propagation environment,the wireless channel fading seriously deteriorates the performance of spectrum sensing.However,the time-variant fading channels viewed as hidden state information are not estimated.The main reason is that the initial designed model of cognitive scenario is relatively simple.In most practical applications,the cognitive radio technology is applied in the dynamic uncertainty of channel environment.Thus,this paper will analyze time-variant fading channels in spectrum sensing,aiming at the promotion of the universality of cognitive radio technology application.The main work of paper is as follows.This paper proposes a new algorithm of joint channel fading estimation in spectrum sensing.Based on dynamic state-space model and the measurement affected by both fading channel and working state of authorized user,two of them can be casted into a Bernoulli random finite set.Then we can design a Bernoulli filtering mechanism,which is implemented by particle filter,and estimates the posterior probability density of the set,so as to detect the working state of the authorized users.On the basis,a cooperative spectrum sensing algorithm of joint channel fading estimation is proposed,and we also puts forward a new spectrum sharing network based on the cognitive router.Compared to the traditional algorithms,the new algorithm not only improves the spectrum sensing performance,but also estimates the whole network dynamic channel state information,which can be used for the network optimization and the communication.The structure of this paper is as follows.The first chapter summarizes the research background,purpose and research significance of this article.The second chapter reviews spectrum sensing,the key technology,in cognitive radio,and classifies and analyzes the advantages and disadvantages of the existing algorithms.The third chapter claims the fundamental theories of the new spectrum sensing framework and the dynamic model of cognitive radio under time-variant fading channels.The fourth chapter designs the single-node joint estimation algorithm,discusses the Bernoulli derived filtering mechanism,invents the algorithm of the accumulative observations,and eliminates the lack of Bernoulli filter algorithm.The fifth chapter puts forward the collaborative joint estimation scheme,and designs the corresponding spectrum sharing cognitive network.In order to overcome the shortcomings arising from the new algorithm applied in cooperative sensing,we designs the reorganization mechanism of particles,which effectively solved the problem of high complexity.The sixth chapter is the summary and outlook of this paper.