| Wireless communication technology and its application has entered the stage of rapiddevelopment, fierce spectrum scramble has arisen. Traditional static spectrum allocationmethod is the root cause of the acute shortage of spectrum resources for wirelesscommunications. However, spectrum utilization tests revealed that most of the authorizedspectrum has not been fully utilized.Thus, cognitive radio technology developed by providinga set of authorized users the opportunity to access spectrum, significantly improve spectrumutilization. Spectrum sensing for cognitive radio physical layer technology, which providesradio-spectrum to meet the communication needs of users through the spectrum of a broadspectrum of environmental perception and utilization of spectrum occupancy information, isthe key to cognitive radio.This paper first outlines the basic concepts of cognitive radio technology, main abilityand key technologies, Then it introduces the existing spectrum sensing in cognitive radiotechnology, comprehensively summarizing the principle and characteristics of spectrumsensing technology. It makes analysis and comparison of single node perception andperceived pros and cons of collaboration in details, and compares their perceptions ofperformance. For low probability of detection of defects caused by single-node-sensingmethod of "hidden cognitive user", the current spectrum sensing method uses a cooperativesense more often. The difficulty of cooperative-sensing research is how to make collaborationcluster and decision fusion. Collaboration cluster is connected for all nodes in the networkand covers an area of more than one cluster, cluster structure determines the advantages anddisadvantages of system performance; and for the three kinds of hard decision rules ofdecision fusion (" OR ","AND""K OUT OF N"),there is a low detection probability, and ahigh false-alarm probability. In this paper, the existing cooperative sensing method based onposition information is proposed on the basis of a clustering cooperative perception algorithm,aiming at improve the performance of spectrum sensing.Chapter3and chapter4is the research emphasis of this paper. Chapter3presents theprincipleã€processes, and performance characteristics of clustering cooperative based ongeographical location information. Compared with other similar algorithms, the proposedalgorithm improvements embodied in the following three aspects: Firstly, differentiatingbetween malicious and non-malicious nodes by analyzing the impact of malicious nodes in acollaboration-sensing; Secondly, using location information to improve the rationality of thecluster; Thirdly, D-S fusion algorithm is improved by using location information mapping bythe different weights of credibility in the decision fusion stage. Algorithm is put forward through the simulation analysis by Chapter4, which iscompared with work with removal of malicious nodes, based on the LACA clumps andcollaboration and D-S fusion collaboration algorithm, respectively.It can see that using theadvantage of the location information. Namely the algorithm get larger detection probability,which ensures that the main user is away from interference; And with low false-alarmprobability, it makes cognitive users can have more opportunity to use the idle spectrum. Thearithmetic complexity of the algorithm is relatively high, however, perceive time is long, itapplies to perception and operation time without special requirements, not for the occasionhigher on the perceived accuracy requirements. Finally, summarize and prospect the full textof the work... |
