Research Of A New Spectrum Sensing Technology Combined With Position

With the rapid development of wireless communication technology， thewireless spectrum resources has been becoming shorter and shorter.To solve theshortage of the wireless spectrum resources, the theory of cognitive radio has been putforward. The theory of cognitive radio is intended to get and use the best availablefrequency band to increase spectrum resources utilization with the cognitive users’ability of perception and reset. As a kind of intelligent communication system,cognitive radio can detect the existence of spectrum hole in authorized frequencyband through the spectrum perception technique, and then adjust its transmissionpower, carrier frequency, modulation mode to take up authorized frequency band.When found the authorized user, the cognitive user will change the parameter of itselfin order not to disturb the authorized user (including not affect the normal authorizedusers to send and receive signals). Spectrum sensing technology is one of the mostimportant prerequisites depend on which the cognitive radio can work efficiently.Therefore, this topic will focus on the research of cognitive radio spectrum sensingtechnology.Otherwise, in the cognitive radio network, knowing the location of the primaryuser has an important effect to the cognitive radio technology, such as spectrumsensing.In the environment of actual cognitive radio network, multipath, Doppler effectand so on may make the signal propagation loss serious attenuation, thus producesinaccurate judgment for spectrum status. To solve this error, this paper proposes anew cognitive radio spectrum sensing technology which combined with the positionof primary users.This paper introduces the concept, model and key technologies of cognitiveradio. Outline the significance and current situation of positioning technology in thefield of cognitive radio; Secondly, expounds the traditional RSS localizationalgorithm implementation process in the cognitive radio network. The result moreaccurately calculates the position of the primary user’s information and transmittedpower. And detailed simulation the influence of the number of second users, samplingquantity and environmental factors to the result of the primary user’s locationinformation and transmitted power estimation; Then based on the actual cognitivenetwork, we give the concept of sensing radius-due to the path loss, when the primaryuser transmitter works, the longest distance that second users will be able to receivethe primary user’s signal; At last, we introduced localization algorithm to cooperationin energy spectrum. And successfully improved the spectrum detection probabilityand reduced the error caused by the nonideal environment of cognitive radio networkcaused by primary user communication better. Make the primary users work better without interference.