Abstract: The technology of cognitive radio can use the untapped spectrum resource to increase the cognitive radio technology efficiency dramatically.Although the spectrum sensing for only one technique is simple,it is not reliable.However,using the cooperative spectrum sensing can improve the capability of spectrum sensing.Recently,most of the studying about the cooperative spectrum sensing is based on one simple condition that is assuming the signal to noise ratio for each cognitive user is similar.In reality,each cognitive radio user will have different environment,which will produce different signal to noise ratio and different influence on the justification of the fusion center.In addition,another important issue is how to improve the performance of CR system while enhancing the energy efficiency.This paper proposed a method of cooperative spectrum sensing based on BP (Back Propagation) neural network which will improve spectrum sensing performance by using the historical information about the spectrum through BP neural network.The simulation identifies the algorithm can reduce the involved cognitive users and the energy consumption,and guarantee the performance of the cooperative sensing at the same time.

Key words: Cognitive radio,BP neural network,Spectrum sensing,Energy efficiency