| With the rapid development and wide application of wireless communications services, the limited spectrum resources and fixed spectrum allocation patterns have led to extremely low utilization of spectrum resources, and becoming scarce spectrum resources to the bottleneck. As an intelligent wireless communication technology, cognitive radio can effectively solve this problem. Cognitive radio can detect spectrum holes of the authorized user, and achieve the secondary use of spectrum in condition of not interfering with the existing licensing system in order to improve spectrum efficiency. Spectrum sensing technology is the key technology of cognitive radio systems, and the research on it has far-reaching significance.This paper mainly studied the detection of single node transmitter, analyzed the effect of detection probability, false alarm probability, threshold SNR and sampling points number to the detection performance of the energy detection method in the different channels. Meanwhile, this paper analyzed co-operation based on energy detection sensing method, and made computer simulation for "and" guidelines and "or" criteria, proved that the cooperation is superior to single-node detection test.This paper emphatically introduced the cyclostationary feature detection method, analyzed the cyclic spectral theory in detail, made the theoretical analysis and computer simulation to the different modulation signals of authorizing users, verified that the cyclic spectral theory not only has immunity to the noise spectrum, but also has the ability of separating and identifying the useful signal. According to expression of cyclic correlation matched filter detection, this paper proposes detection statistics which is composed of set-average frequency smoothed cyclic periodogram algorithm. Simulation results show that it is not only superior to the energy method and cyclostationarity feature detection, but also don't need to know prior knowledge of detection signal. |
