Research On Cooperative Spectrum Sensing Algorithm In Cognitive Radio Networks

With the rapid development of economy and science,the wireless communication traffic grows fast.However,the frequency spectrum resource is very limited and the distribution of it is uneven.In the context,cognitive radio is proposed and considered to be one of the most effective methods to ease spectrum situation.Accurate spectrum sensing is the precondition of realizing cognitive radio networks.The task of spectrum sensing is to find spectral holes.It includes two aspects: to determine whether spectrum holes exist and avoid interference to the primary users.In the premise of not interfering with the primary users,the spectrum efficiency is maximally improved,which makes the spectrum sensing satisfy the fast and accurate requirements.The cooperative spectrum sensing is often used to improve the spectrum sensing performance.However,it does not mean the more cooperative sensing nodes are,the better the is.How to select suitable sensing nodes to participate in fusion is a key problem in the cooperative spectrum sensing.With taking about the high frequency spectrum utilization and high transmission efficiency in cognitive radio networks,the computation of cognitive radio networks become more and more complex.A big computation would increase the energy consumption,deteriorate the the desired spectrum detection quality,and shorten the life of the system.This paper proposed a new cooperative spectrum sensing algorithm,in which the sensing nodes to participate in fusion is selected according to the reliability of sensing nodes.The historical detection probability and false alarm probability is introduced to evaluate the reliability of sensing node.It improve the performance of the cooperative spectrum sensing.In order to reduce the computation and improve the spectrum sensing performance,this paper proposed a cloud cooperative spectrum sensing algorithm based on phase compensation,In the algorithm,the received signals in the sensing nodes are sent to the cloud,compensated in phase and combined into one signal.Then,the combined signal is used to detec whether the primary user is present.It improves the spectrum sensing performance effectively.The simulation results show that the detection performance of the proposed two algorithms both have 2-4 dB advantage in signal noise ratio compared with other similar algorithms.