Cooperative Spectrum Sensing Method And Security In Cognitive Radio Networks

To alleviate the present situation of the increasing scarcity of spectrum resources, cognitive radio becomes a key technology. By reusing the authorized spectrum resources, it effectively alleviates the contradiction between the spectrum scarcity situation and the growing access requirements. The spectrum sensing is the foundation of cognitive radio networks. It is an important method to ensure the primary users away from harmful interference and improve spectrum utilization. However, the premise is as much as possible to improve the spectrum efficiency, also to ensure that the primary user(primary users) can communicate properly and get rid of harmful interference. Thus, how to optimize the spectrum sensing parameters which can get maximum gain at the low cost is a key part in the wireless communication environment. The transmission of signals is susceptible to the path loss, shadowing, multipath effects, and sensor nodes themselves launch a variety of attacks such as tamper the perception information, forgery, eavesdropping, etc., which results in an error verdict. In this paper, we carry out our cooperative sensing research work based on a more practical, unsafe cognitive radio network with malicious users. The obtained research results are as follows:1. Based on a more practical cognitive radio network with malicious users, we study the spectrum sharing network model based on the cooperative spectrum sensing that the secondary user can dynamically adjust its transmit power based on cooperative sensing results. To avoid significant reduction in performance of spectrum sensing system caused by malicious nodes, we aim to study how to improve the performance of cooperative sensing. By introducing the convex optimization problem, the secondary network throughput is maximized under the certain detection probability conditions and the corresponding power constraints. Simulation results show that whether or not there are malicious nodes, the algorithm is efficient in calculating optimal sensing time and the optimal transmit powers, and the secondary network throughput is increased when the maximum interference power limits and the maximum transmit power restrictions are decreased.2. Make further security studies considering of the four insecurity factors in current cognitive radio networks. As for the smart attack mode, we propose a cooperative spectrum sensing model based on trust values. In the experimental simulation part, we compare the detection performance with the other two extreme cases from the false alarm probability and average throughput aspects, the results indicate that the cooperation sensing program can effective defense of such intelligent malicious nodes through dynamically adjust the trust value of each sensor nodes, and ensure that the detection performance of the entire network is good enough.