Study Of Cooperative Spectrum Sensingon On Cognitive Radio

Cooperative spectrum sensing is the technology that improves the detectionperformance by using the space diversity gain between different cognitive users. Thispaper mainly studies cooperative spectrum sensing algorithm in cognitive radio，andfocuses on the application of sequential change point detection and DS evidence theoryin cooperative spectrum sensing. First of all, the basic concepts of cognitive radio andthe recent developments of spectrum sensing technology are introduced. Followed bywhich there is a study of the traditional cooperative spectrum sensing algorithms, itsfusion rules and existing problems. Based on the previous introduction, the cooperativespectrum sensing methods based on sequential change point detection are studied forthe uncertainty of the licensed user’s signal activity. Then a modified method isproposed, which can detect signal status changes in the case of the current signal statusis unknown and reduce the number of judgment by using energy detection statisticsthereby reducing the overhead. These have been verification through simulationanalysis. Afterwards, this article studies the cooperative spectrum sensing methodsbased on DS evidence theory. Considering that wideband report channel is required inexisting methods and the detection performance deteriorates severe under the conditionof high level conflict, an improved scheme is proposed, which introduces the projectionapproximation algorithm in the local sensing period to reduce the sensing datatransmitted to fusion center and puts forward a method for dealing with high levelconflict utilizing the credibility weighted. The new scheme reduces the requiredreporting channel bandwidth and improves the performance under the condition of highlevel conflict which is validated by our simulation results.