Research On Energy Saving And Security Cooperative Spectrum Sensing Schemes In Cognitive Radio Systems

In recent years, cognitive radio has become a hot spot of research as it is a promising way to resolve the urgent problem of wireless spectrum scarcity. Cooperative spectrum sensing method, an important spectrum sensing technology, has drawn a lot of attention. This method efficiently resolves the’hidden terminal’and’fading’problems, promoting the detection performance of the system in great deal. However, cooperative spectrum sensing method demands more communication overhead causing the secondary users to consume more energy. Besides, the cooperation process makes it easier for the cognitive radio system to be attacked and cause new safety problems. Therefor, this thesis studies the cooperative spectrum sensing methods to decrease the communication overhead and improve security degree.In the aspect of energy conservation, since the existing low communication overhead cooperative spectrum sensing methods are mostly based on unrealistic assumptions, we put forward a practical method to control the communication overhead. This method can save a lot of communication overhead through controlling the sending process of sensing results. The simulation results show that this method enables the cognitive radio system to trade the detection ability for communication overhead. So the cognitive radio system can save great amount of communication overhead while keeps the detection performance nearly unchanged.In the aspect of safety, this thesis studies the security threats to cooperative spectrum sensing and copes with it through sensor selection. Through choosing secondary users that are relatively apart from each other we can decrease the effect caused by Primary User Emulation (PUE) attack. Besides, our method doesn’t need huge amount of calculation which is required in similar methods. The simulation results show that our method can greatly decrease the effect caused by PUE attack to improve the system detection performance under attack.