The Research Of Cooperative Spectrum Sensing Technology In Cognitive Radio

With the rapid development of wireless communication technology, the number of wireless users have increased dramatically, combined with the spectrum resource utilization is unreasonable, so the spectrum resource is more and more nervous. In order to improve the utilization of existing spectrum, so the Cognitive Radio technology arises at the historic moment. Spectrum sensing is the key to the realization of cognitive radio, this paper mainly studies the spectrum sensing technology in cognitive radio, focusing on the cooperative spectrum sensing.Firstly this paper introduces the research background、significance、developing surnmary and its studies status at home and abroad of cognitive radio,then I study the single node spectrum sensing method and focusing on the cooperative spectrum sensing method.In the single node spectrum sensing method,I study matched filter detection, energy detection and cyclostationary feature detection, Because the single node spectrum sensing method is difficult to overcome affect of various fading in the actual communication environment. So this paper further studies Cooperative Spectrum Sensing. and focus on cooperative spectrum sensing based on data fusion and clustering collaborative perception done in-depth research.cooperative spectrum sensing based on data fusion is studied in the third chapter.In cooperative spectrum sensing. Firstly I studied the cooperative spectrum sensing based on hard decision fusion, including AND, OR,K of N fusion rule.Then studied cooperative spectrum sensing based on soft decision fusion, including Equal Gain Combining and Maximal Ratio Combining. Then I focus on cooperative spectrum sensing algorithm based on the best fusion rule (Chair-Varshney). And the simulation is carried out under AWGN channel,the result showed that the collaborative spectrum sensing algorithm based on data fusion is effective to improve the detection performance. Finally,this paper puts forward a EGC-based cluster cooperative spectrum sensing algorithm under Log-Normal shadow-Fading.The simulation results show that this method significantly reduces the reporting channel bandwidth.In addition, clustering collaborative spectrum sensing method can enhance the detection performance and can be very good to overcome the hidden terminal problem in a communication channel with noise condition.Finally, this paper apply the clustering technology into cooperative spectrum sensing, the cooperative spectrum sensing method based on clustering is fully analyzed.I proposed a cluster-based cooperative spectrum sensing algorithm with double adaptive energy thresholds and optimal data fusion. In the algorithm,firstly,the threshold determination method of adaptive double thresholds is derived.Then describes the application process of optimal data fusion in cooperative sensing. And choose cognitive user of the best channel condition in the cluster as cluster head, All the local perception results using C-V fusion rule are merged for the first time in the cluster head.Then fusion results of all cluster heads are sent to the global fusion center. In the global fusion decision fully considering the different signal-to-noise ratio and distance. The simulation results show that the algorithm effectively improves the detection performance.