Research Optimization On Proactive Eavesdropping Via Pilot Contamination System

Due to the turbulence of the international community,several major terrorist attacks happened in recent years remain people of the instablility and insecurity of the world.We suppose that there is a legitimate organization,like a government security agency,wants to surveil and eavesdrop the suspicious users.Because of the fact that the legitimate eavesdropper locates further away from the suspicious transmitter,as compared to the suspicious receiver.The eavesdropping link from the suspicious transmitter to the legitimate eavesdropper is weaker than the suspicious link from the suspicious transmitter to the suspicious receiver.If the legitimate eavesdropper still adapts the traditional passive eavesdropping approach,the legitimate eavesdropper can’t achieve an ideal eavesdropping performance.The appearance of the proactive eavesdropping represents a new paradigm shift in wireless physical layer security,which has made up for the lack of eavesdropping technology in the security field.Proactive eavesdropping can make the legitimate users achieve a good surveillance performance under the unsatisfactory condition and reduce the information rate of suspicious link.To further improve surveilling performance,in this paper,we use the pilot contamination technique to help the legitimate eavesdropper’s proactive eavesdropping,which spoofs the suspicious transmitter on channel estimation by sending the same pilot signal as the suspicious receiver,and lets it leak information in the direction of the legitimate eavesdropper during its transmission.However,this technique may fail when an anti-pilot-contamination mechanism called ``Energy Ratio Detector(ERD)’’ is applied at the suspicious receiver.To achieve a better legitimate surveillance performance,in this thesis,we propose a pilot contamination for proactive eavesdropping systems.The legitimate eavesdropper sends the pilot contamination signals to the suspicious transmitter as well as sends the jamming signals to the suspicious receiver.Thus legitimate receiver can combat the ERD at the suspicious receiver and further improve the eavesdropping performance.We studied and analyzed the influence of the power of pilot contamination signal and the power of the jamming signal on the eavesdropper performance of the legitimate eavesdropper.Futhermore,the proactive eavesdropping rate maximization algorithm is proposed.The main work is summarized as follows:1.We proposed and established a pilot contamination for proactive eavesdropping systems,and analyzed the influence of pilot contamination attack on the suspicious link.According to the theoretical analysis and simulation result,we found the pilot contamination can improve the information rate of the legitimate eavesdropper.2.We derived a closed-form expression for the probability of pilot contamination being detected by the suspicious receiver,and used it to obtain a closed-form expression for the eavesdropping rate.The simulation results show that with the increase of the pilot contamination,the higher is the detection probability.3.We proposed an algorithm to maximize the eavesdropping rate by jointly optimizing the pilot contamination power and jamming power via two-dimensional search.Simulation results show that the proposed proactive eavesdropping rate maximization algorithm can significantly improve eavesdropping rate,as compared to other benchmark schemes.