An Overlay-based Cooperative Relaying Transmission Scheme For Cognitive Radio Networks

The development of wireless communication requires more radio spectrumresources, however, the remaining available free radio spectrum resources areincreasingly limited. And meanwhile the utilization rate of most spectrum resourceofficially assigned by radio spectrum management agency is still very low. And theradio spectrum management mechanism of static and fixed spectrum allocation methodis considered to be one of the important reason of these contradictions. Cognitive radiotechnology can effectively alleviate the above contradiction and dynamically managethe spectrum resource.At the same time, the development of the wireless communication servicesrequires better communication quality and faster transmission rate. The cooperativecommunication technology makes mutual assistance between one or moresingle-antenna node transmission to form a virtual antenna array, played the role ofspace diversity, can significantly improve the transmission rate and coverage against thevarious fading.This thesis is in the above context, and the integration of cognitive radiotechnology and cooperative communication technology as the main object of study.Firstly, summarize and analyze the related research achievements of current dynamicspectrum sharing based on cognitive radio technology and cooperative communicationtechnology, research in cognitive wireless network scene based cooperativecommunication and overlay spectrum sharing. Basis this scene, set up two systemmodel, respectively, uses DF(Decode-and-forward) and AF(Amplified-and-forward)cooperation technology,which can improve the data transmission rate of primary user,and as a return, the cognitive user can obtain the opportunity of accessing the spectrumof primary user. In the case of incomplete information, a reverse auction-basedcognitive relay selection algorithm has been proposed, and studied the utility function ofprimary and cognitive user, then make the improvements on the utility function toenhance the enthusiasm of primary user and avoid the existence of fraud by thecognitive user, studied the method for solving optimization of improved utility functions. The simulation results show that the mechanism use both the DF and AFcooperation technology, can enhance transmission rate of the primary user, meanwhile,the cognitive user obtain the opportunity to transfer its own data, so as to achieve awin-win situation.