Research On Spectrum Sensing Based On Double-threshold Energy Detection In Cognitive Radio

Wireless communication technology has been developed rapidly and got widespread attention since 1970s.However,with the coming of the information age,the number of mobile terminals and the urgent need for high-speed data transmission keep increasing and it leads to the shortage of radio spectrum resources.The existing spectrum resource allocation scheme cannot satisfy the wireless communication needs,so Dr.Mitola Joseph proposed cognitive radio technology,it allows the secondary users to access the authority spectrum opportunistically when the primary users not using the spectrum.By this way,the spectrum utilization can be improved and releases the shortage of spectrum resources.Cognitive radio contains technologies like spectrum sensing,spectrum accessing,spectrum management and spectrum sharing.Spectrum sensing is aimed to sense the state of the target spectrum,it is the first step of cognitive radio and the information resource of spectrum decision.Therefore,the study of spectrum sensing algorithm is important for the promotion and development of cognitive radio.The main work and innovation are as follows:1.Analysed the development and outstanding output of cognitive radio technology at home and abroad in recent years,then make an introduction of the commonly used spectrum detection algorithms and discuss their advantages and disadvantages.2.Proposed an improved algorithm based on the double threshold spectrum energy detection algorithm.The improved algorithm can avoid the detection error caused by instantaneous signal energy drop.Compared with the traditional double threshold algorithm,the proposed algorithm can significantly improve the accuracy of spectrum detection while maintaining low complexity.Analyzed the influence of channel environment made on spectrum sensing performance,and the robustness of the proposed spectrum sensing algorithm is verified in Rician channel,Rayleigh channel and Gauss channel.3.Proposed a cooperative spectrum sensing algorithm,the sensing users make local sensing by energy detection,then upload the measurements to fusion center which will make the final decision based on a novel fusion rule.The novel fusion rule combined the K rank criterion in the hard decision and the improved equivalent gain synthesis(EGC),it can not only decrease the system overhead but also improve the sensing ability of the system.