Research On Cooperative Spectrum Sensing Algorithms In Cognitive Radio

The need for higher data rates is increasing as a result of the transition from voice-only communications to multimedia type applications. Considering the limitation of spectrum resources, the current static spectrum allocation system can’t adapt to the equipment of growing high speed data transmission obviously. Cognitive Radio technology is an effective method to solve the spectrum crowded, which introduce a band opportunity access to unauthorized users. A major factor of Cognitive Radio is spectrum sensing. Cooperative spectrum sensing can effectively avoid the influence of Primary user positional uncertainty and the shadow effect of the Single user perception process. It can provide more stably and reliably sensory information.Cooperative spectrum sensing network has more users, and sensing of performance is not the best when all nodes take part in the cooperation. Some sensing nodes do not have the stronger sensing ability, so they do not need to take part in the cooperation. At the same time, it just needs to determine the sensing number of the channel. So there is a problem of the optimal nodes and channels.In order to reduce the consumption of energy in the process of sensing and the malicious nodes to take part in the sensing, this thesis mainly studies the cooperative spectrum sensing method of optimize the sensing nodes and the number of channels. In this method, it confirms the choice range of cooperative sensing nodes through calculating the reputation of each node, and obtains the choice range of number of channel according to user’s business demand. It chooses the number of sensing users and the channel based on satisfying the requirements of system, realizing the purpose of reduction of sensing spending in sensing process. With the change of the authorized channel’s occupancy rate and the system business’s demand, this method can change the number of the sensing node and the channel dynamically. The simulation result show that this method can minimize the system’s the sensing costs within a certain scope through choosing the number of the optimized node and channel. It is better than the traditional cooperative spectrum sensing method.