Research On Collaborative Spectrum Sensing Based On User Selection

With the rapid development of communication services and the social and economic globalization,wireless communication has become an integral part of mankind all over the world.However,due to the low spectrum efficiency,the spectrum resource is in serious shortage,and it gradually becomes a key issue to be solved urgently for the further development of the Internet.In order to improve the utilization of spectrum resources,cognitive radio technology is generated.It allows unlicensed users to use idle frequency bands,access and use authorized spectrum without interference to authorized users.Collaborative spectrum sensing is the key of cognitive radio,this paper for its detection performance and energy efficiency of two important indicators in-depth study,the specific work is as follows:First,on the research of detection performance in cooperative spectrum sensing,this paper focuses on the single-threshold energy detection easily affected by noise interference and channel fading,as well as the traditional spectrum sensing strategy may cause greater detection delay and overhead issues,so we proposes a user-selected cooperative spectrum sensing strategy based on double-threshold energy detection.On the one hand,in the local sensing stage,the double-threshold energy detection algorithm based on maximal ratio combining is adopted and the influence of signal interruption is taken into account,thus overcoming the problem that traditional single-threshold energy detection is easily affected by noise interference and channel fading.On the other hand,after uploading local sensing results to the fusion center stage,we add a central user system model with sensing function to perform two-step detection and report by selecting the cognitive users with the best signal-to-noise ratio to reduce the reporting overhead and the average sensing time.Through the simulation analysis of the example data,the scheme can improve the detection performance and reduce the average sensing time,and can also minimize the missed detection probability by adjusting the sensing time.Second,in the research of energy efficiency of cooperative spectrum sensing,all cognitive users in the current cooperative spectrum sensing scheme need to report the local sensing results.When the number of cognitive users is large,it will cause higher energy consumption and other issues,we proposed a user-selected collaborative spectrum sensing scheme based on energy efficiency.First of all,only one cognitive user in the scheme broadcasts its local detection results.All other cognitive users who oppose the broadcast result will report their local information to the fusion center,and the agreed cognitive users will remain silent.Therefore,the fusion center will get the perception results of all cognitive users and make a global decision.Second,the fusion center of the scheme also has the ability to make initial decisions so as to avoid unnecessary cognitive processes,and we combine the perception of historical information to improve the choice of broadcast users to maximize energy efficiency.Finally,the simulation results show that the scheme reduces the number of cognitive users who need to report information and effectively improves the energy efficiency of the system.