Research On The Security In Cognitive Radio Network

The cognitive radio is a wireless technology which can improve the utilization ratio of frequency spectrum. Because the cognitive radio is one of the wireless communication technologies, it has the problems which the common wireless communication techniques have. Also, it can bring some novel security threats. The primary user emulation is one of the serious security threats. If the secondary user detects the existing primary user while it is using the idle grant spectrum, it should quit this spectrum immediately to prevent the interference of primary user. Based on this feature, when the primary user emulation attacker detects an idle grant spectrum, it can send a signal similar with the primary user’s characteristic to prevent other secondary users to use this spectrum. The primary user emulation attack seriously interferes the spectrum sensing process and dramatically decreases the usable spectrums which other secondary users can employ.In the WRAN system, IEEE802.22workgroup has already allotted the television video broadcast spectrum to the cognitive radio users. Aim at the problems of primary user emulation attack to the TV broadcast tower primary user and in order to recognize the truth and the false primary user signal, this paper brings forward a recognition project combines with three-dimensional positioning of the signal source and signal characteristic detection.Firstly, this paper introduces the history and the present status of the improvement of cognitive radio. Then, this paper analyses the existing security problems in the cognitive radio system and advances the security plan to solve these problems.Secondly, to solving the threat of the primary user emulation in cognitive radio networks, secure localization is proposed as a security scheme based on three-dimensional positioning of the signal source location. Chan Location Algorithm is expanded into three-dimensional form and the signal propagation time is used to estimate the source location with the weighted least square iteratively. The simulation results show that, this method has good performance.Finally, the characteristic detection of DVB-T TV signal has been researched. This study includes the generation of DVB-T signal, the cyclostationarity characteristic detection of DVB-T signal and the analysis of DVB-T signal’s symbol rate estimation based on autocorrelation. Through the simulation, this paper’s scheme has a sound performance, and can effectively solve primary user emulation in cognitive radio networks.