Research On Technology Of Cooperative Spectrum Sensing In Cognitive Radio Networks

As wireless technology is widely applied in mobile communications, public safety, and broadcasting, modern society is increasingly dependent on the radio spectrum resources. In recent years in particular, new wireless communication technologies such as wireless local area networks, wireless personal area networks, wireless metropolitan area networks technology developed rapidly, which make people raise a higher demand of broadband wireless applications, spectrum resources are increasingly scarce.On the other hand, the survey found a significant number of spectrum utilization is very low and extremely uneven. Spectrum sensing technology of cognitive radio networks is one way to solve the problem. Cognitive radio networks as a kind of revolutionary radio-based intelligent spectrum sharing technology, which has been assigned frequency bands through the reuse of spectrum resources, which significantly improve the spectrum utilization. In this paper, we introduce the cognitive radio technology and some critical problems first. Several spectrum sensing algorithms for single cognitive user is analyzed and then cooperative spectrum sensing algorithm is introduced from the perspective of network structure and fusion rule as single user spectrum sensing algorithm is not good enough. IEEE802.22System based on cognitive radio technology is also briefly introduced. In chapter3and chapter4, the main contribution of this paper is described in detail. At the beginning the sensing performance of cognitive radio networks including two cognitive users equipped with multi-antennas is analyzed. Two users detect the primary user cooperatively. Simulation results show that the technology of cooperative spectrum sensing and multiple antennas can improve the sensing performance effectively. In addition, a cooperative spectrum se-nsing scheme exploiting a certain number of cognitive users based on multiple antennas is also analyzed in the system. The results show that the sensing performances can achieve optimum by cooperative spectrum sensing of some cognitive users with high SNR rather than that of all cognitive users. We also apply multi-antenna technology to the sensing scheme which can improve the sensing performance proved by the simulation results.