| With the rapid development of the wireless communication business, more and more radio spectrum resources are needed, it makes that the current spectrum resources become less and less. Therefore, the study of the cognitive radio technology has great realistic significance.The core technology of the cognitive radio is that radio communication equipment should have the capacity of finding the"spectrum holes"and using rationally, namely spectrum sensing. These algorithms of spectrum sensing are studied and compared, which include emission source detection, cooperative detection and interference temperature detection,among these that the mission source detection algorithm obtains mainly matched filter detection and cyclostationary characteristic detection, after acquiring the theoretical basis, development and tendency of the cognitive radio, and analyzing the existing problem and common methods. Meanwhile, some common blind signals separation technology and the separation technology of signals with same frequency are studied and analyzed.The main research of paper includes:1,The first stage of spectrum sense is that the energy detection algorithm is used to detect free frequency channels, cognitive user can access the free channel after detecting the spectrum holes.2,Cognitive user need detect the accessed channel timely while transmitting datas using detected channel. Once other's signals access this channel, cognitive user should separate the mixed signals with same frequency using the method of adaptive filter, and then estimate whether the accessed signal that is primary user's signal or not.The design of this system makes the mature signal separation technology applied to the new technology field that is cognitive radio, realizes the combination of the tradition and innovation, and then, to a certain degree, alleviates the situation of the shortage of spectrum resource. The whole system has high reliability and real-timely. |
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