Research On Technology Of Cooperative Spectrum Sensing In Cognitive Radio Networks

Because of the development of wireless communication technology, the demand for resource of spectrum has been increasing rapidly. However, the traditional mechanism of spectrum allocation leads to waste of spectrum resource. On the other hand, new services can not acquire enough spectrum resource. In order to solve this problem, cognitive radio technology is developed which can utilize the unused authorized spectrum and increase the efficiency of spectrum by dynamic spectrum access.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. IEEE802.22 System based on cognitive radio technology is also briefly introduced.In chapter 3 and chapter 4, 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. The 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 sensing scheme exploiting a certain number of cognitive users based on multiple antennas is also analyzed in IEEE802.22 system. The results show that the sensing performance 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.