Research Of Cooperative Spectrum Sensing Algorithms Based On Cognitive Radio

With the rapid development of wireless communication technology, spectrum resources are increasingly strained. Most of the spectrum resources are used as licensed bands, such as the television broadcast band, but the spectrum resources of non-licensed bands are much less. Therefore, we need to maximize spectrum efficiency. Cognitive radio as a smart radio, have the knowledge, perception, learning and adaptation features, can be able to optimally apply its wireless capabilities. Its core idea is that without affect the licensed bands'normal communication, then let the wireless communication device have the ability of finding and rational using "spectrum holes". Spectrum sensing technology is one of the most basic and critical technologies of cognitive radio. This paper carries comprehensive study on how to improve the detection performance of spectrum sensing technology.This paper recounted the background and significance, research status, key technology and research direction of cognitive radio, analyzed and researched the local spectrum sensing technology, chose energy detection algorithm as a research focus as a result of cognitive radio technology must having ability to detect various primary user signal on the basis of comparing the different detection algorithm. Separately researched and simulated the performance of energy detection algorithm under the AWGN channel and Rayleigh channel.Due to inevitably exist multi-path fading and shading in wireless environment, detection performance has a decline under the fading channel in local spectrum detecting scheme. In order to overcome the deficiency of local spectrum sensing algorithm, this paper further researched multi-user cooperative spectrum sensing. The paper mainly researched OR criteria and AND criteria of cooperative spectrum sensing technology, and separately simulated the detection performance of the two criteria, then analyzed the detection performance of cooperative spectrum sensing algorithm combined with the simulation results. Meanwhile, this paper also introduced the space diversity technology of cooperation spectrum sensing technology and several new research directions of cooperation spectrum sensing algorithm.Finally, this paper put forward to the mechanism of multi-antenna receiver to collaborate again, drawn from the simulation, the mechanism further improved the performance of spectrum sensing. In addition, when the multi-antenna receiver choice a fusion criteria, the simulation results also can guide the fusion center to choice which fusion criteria in order to make the optimal detection performance.