The Research Of Cooperative Spectrum Sensing Based On Cyclostationary

In Cognitive Radio(CR) networks,Secondary Users(SUs) perform spectrum sensing waitting to access the licensed band, this improves the utilization ratio of the licensed band and is one of the effective method to solve the lack of radio spectrum. Spectrum sensing is the basic of the spectrum sharing, spectrum reconfiguration, et al, so its efficency and accuracy is very important. Energy detection has become the common method of spectrum sensing, but its performance suffers seriously from the Noise Power Uncertainty(NPU), the low Signal-to-Noise(SNR) environment, et al. As the wireless communication environment becomes more and more complex, such as the high business volume, existing malicious users, et al, the sensing performance of traditional energy detection declines fast, even invalid.The spectrum sensing based on Cyclostationary can distinguish the signal and noise, even recognize the different signals according to theirselves periodicity, and overcome the problem of the energy detection under the complex wireless environment. As the CPU of terminal devices is more and more fast, which offsetes the high computational complexity of the Cyclostationary spectrum sensing. Research the spectrum sensing based on Cyclostationary has great practical significance.In the Cognitive Radio networks, the detection performance of primary user's randomly arriving during the sensing period is poor. Firstly, an improved spectrum sensing method exploiting the cyclostationary feature is proposed, which adds the second half sampling values of sampling signal to the first half. The method improves the detection performance by enhancing the test statistic even though the sensing time is not added. Then, detection probability, false probability and throughput are analysed theoretically. Simulation results show that the proposed method performs better on detection performance and throughput than the conventional spectrum detection and the conventional Cyclostationary spectrum sensing.In the process of frontal research, Cyclostationary has better sensing performance than energy sensing. So we can combine it with the cooperative sensing to resolve the malicious behaviors in the security domain of Cognitive Radio.The current methods to resist Primary User Emulation Attacks(PUEA)are almost based on energy spectrum detection, which have some shortcomings, such as the special application environments, easily be emulated and so on. We propose a cooperative spectrum sensing algorithm based on Cyclostationary to resist PUEA. This method analyses the local spectrum sensing results and compares it with the statistics results without the malicious user, to find out if there are malicious users. Simulation results show that the method performs nice on sensing spectrum and resisting the PUEA.