Collaboration In Cognitive Radio Detection Algorithm

With the development of wireless communication technology and the current wireless applications continueing to expand, the lack of spectrum resources becomes a urgent problem in the process of research in wireless applications. However, some studies suggest that the large number of precious spectrum resources has not been fully utilized currently, and even in many cases is idle. In order to effectively address the problem of scarce spectrum resources, a new spectrum usage pattern---Cognitive Radio (CR) are gradually being people's attention.The research of this paper is cooperative spectrum sensing in cognitive radio. Firstly, local spectrum sengsing methods including energy method, match filtering spectrum sensing and Cyclostationary spectrum sensing are analyzed and compared. In order to overcome the shadows and fading effects, cooperative spectrum sensing that is usually achieved in two ways, one of which is using centralized or distributed data fusion, the other space sub-set are introduced. In this thesis, the first method is used.In this paper a centralized network scenario based on the IEEE 802.22 standard for wireless local area network (WRAN), use unused television channel to transmite information. The proposal scheme solve the reliability of interactive information transmittion, and minimal interference to the primary users. According to the protecting area, In this paper a distributed network divided communication between secondary users into two phases, the first stage is the communication between the cognitive users within the protected area and the ones outside the region, the second stage is the communication between the cognitive users outside the region and the user receiver. Simulation results show that increasing the number of sensing nodes can improve the information transmission rate, meanwhile, have not interfere with primary users.