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Research On Spectrum Sensing Of Cognitive Radio

Posted on:2014-02-13Degree:MasterType:Thesis
Country:ChinaCandidate:X F LinFull Text:PDF
GTID:2248330395983940Subject:Signal and Information Processing
Abstract/Summary:PDF Full Text Request
With the development of wireless communication technologies, the demand of wirelesscommunication services is increasing, prompting the contradiction between supply and demandfor spectrum resources increasingly apparent. In the real environment, licensed spectrumresources are not occupied all the time, otherwise, most of the time they are in idle state, bysensing and occupy idle spectrum resources, cognitive radio technologies improve the utilizationof spectrum resources. Spectrum sensing is a key technology and precondition of cognitivetechnology, which can sense vacant spectrum and emergence of primary users. A detailedanalysis of existing spectrum sensing technologies and applications are introduced in thedissertation.In this article, we propose an improved based on random matrix cooperative Maximum andMinimum eigenvalue ratio algorithm. By the decomposition of the sensing signals, whichincrease the number of logic signals in the signal matrix. In addition, for the decomposition ofthe signal processing, due to the decomposition of the original signal which shorten theperceived timeslot. At the end, more signal Related Information can be obtained from the signalcovariance matrix. Above this can improve the accuracy of the data processing, and thenimprove the overall spectrum sensing performance. Finally, we verify that this improvedalgorithm has better performance than the traditional algorithm through analyzing andsimulating.In traditional adaptive cooperative spectrum sensing method, generally select the better usersensing data which with better channel conditions from the cognitive environment for the dataadaptive fusion. That required the sensing channel’s signal-to-noise ratio is known, which meansthe algorithm’s sensing performance relate to signal-to-noise ratio. But in practice, due to noiseuncertainty, various cognitive users’ channel conditions is unknown. Therefore, in order toweaken the influence of the signal-to-noise ratio, this article introducing the random matrixtheory to adaptive spectrum sensing. First, make the energy judgment in each cognitive userlocal, by which divides all sensing users to reliable users and unreliable users. Then, the reliableuser’s sensing data is transmitted to the cognitive base station, in which using matrix theory tofurther process sensing data and obtain the final verdict value. Finally, compare the verdict valueand the judgment threshold and make the final judgment. Through analysis and simulation shows that, the proposed algorithm can keep the detection performance, simultaneously reduce theinfluence by channel signal-to-noise ratio to the detection performance.
Keywords/Search Tags:Cognitive Radio, Spectrum Sensing, Random matrix theory, Eigenvalues
PDF Full Text Request
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