Energy Saving On Cooperative Spectrum Sensing And Research On Improved Defence SSDF Attacks

In cognitive radio(CR),in order not to interfere with the normal communication of the primary user,the cognitive user must quickly and accurately perform spectrum sensing to effectively utilize the idle spectrum.However,due to multipath fading,shadow effect,hardware and other factors,single-user spectrum sensing is very difficult to guarantee the accuracy,in order to solve this problem,a multi-user cooperative spectrum sensing technology was proposed.Cooperative spectrum sensing requires multiple cognitive users to participate in the perception of the same target frequency band,and then integrate the sensing information of each cognitive user to make the final decision.Although the way of cooperative sensing improve the sensing performance by using the advantage of diversity gain in a certain extent,but also poses a new security threat-spectrum sensing data falsification(SSDF)attack,namely in the process of cooperative spectrum sensing,there are some malicious cognitive users,they falsify the local sensing information of each user,as a result,the authenticity of information fusion result is greatly reduced.Therefore,in order to ensure the accuracy of the cooperative spectrum sensing to a great extent,it must improve the robustness of cooperative spectrum sensing.This paper is studied mainly based on cooperative spectrum sensing,and based on the traditional cooperative spectrum sensing fusion method to make improvements,to achieve the purpose of resisting SSDF attack.First,this paper briefly analyzes several single-user spectrum sensing method and introduce the CR network security threats SSDF.Cooperative spectrum sensing algorithm is introduced at the same time in centralized and distributed and introduced the fusion rules of cooperative spectrum sensing.Secondly,because most of the literature only pays attention to improve the detection performance of system,while ignoring the sensing time of cooperative sensing and the energy dissipations of the SU in perception phase processing data.So in the third part of this paper,according to the sensing time and energy loss problem in cooperative spectrum sensing is studied.Based on the hard decision fusion rules of cooperative spectrum sensing technology improved energy detection collaborative spectrum sensing algorithm is prosed.The energy detection stage of SU in the total sample data is divided into two parts,the first step is less than the total sample count half of the data is fuzzy sensing.If you can get the final decision,cooperative sensing will end;if the first step cannot get the final decision,the second step is accurate energy sensing.And in the second algorithm to make full use of the first step perception results,improve energy utilization of the system.The simulation results show that the sensing time and energy loss of the proposed algorithm is significantly reduced compared with the traditional cooperative spectrum sensing algorithm.Finally,SSDF is a kind of typical attack way based on cooperative spectrum sensing technology in cognitive radio network,which malicious users will send the wrong sensing data to the fusion center by changing the perception data of itself and misleading the fusion center to make the wrong decision.In order to achieve their own purposes and give CR a huge security risks.In the fourth part of this paper,we do a research on cooperative spectrum sensing against SSDF,which is based on soft fusion.On the basis of traditional linear weighted fusion algorithm,we propose a soft fusion algorithm based on improved reputation.In this algorithm we taking the influence of historical perception data of SU for the current time into account and we take the time decreasing factor to measure the historical data.Then through each SU in each integration services to provide quality of service to dynamically update their credibility,and according to the average credibility to allocate the weighted coefficient in the process of SU each integration.Finally through the simulation analysis,the detection performance of improved algorithm is superior to the traditional linear weighted soft fusion algorithm.