Research On Key Technologies Of Physical Layer Security In Wireless Communication System

Security is an important indicator to measure the performance of the communication system.Whether the information transmission of the communication system can be sufficiently protected is the basic condition for the existence and application of this communication system.The current wireless communication system follows the cryptographic protection mechanism in the traditional wired communication system,and uses the key encryption algorithm at the upper layer of the network protocol stack to encrypt the data,thereby ensuring the security of data transmission.However,due to its openness and flexibility,wireless communication systems are facing more severe security challenges than traditional wired communication systems.Unlike the starting point of traditional cryptography to protect information,the physical layer security technology protects the communication system from the physical layer at the bottom of the network protocol stack.It uses the time-varying and fading characteristics of the wireless channel as a natural feature.The key element encrypts and protects the information,and can effectively interfere with the eavesdropping behavior of the illegal user on the basis of not affecting the normal communication between the legitimate users,so as to achieve the purpose of protecting the communication system for secure communication.Based on the current status of existing physical layer security research,this paper mainly improves the physical layer security from the perspective of signal processing,and conducts in-depth and detailed research on the two key technologies involved,mainly including the following:Firstly,the key technology of artificial noise(AN)in physical layer security research is studied.To solve the problem of insufficient safety performance of the existing adaptive artificial noise-based secure transmission method,an improved constellation rotation-based artificial method is proposed.The safe transmission method of noise.According to Channel State Information(CSI)and transmitted symbols of the legal channel,the transmitter performs artificial constellation rotation at a certain angle according to the channel state information of the legal channel,so that the artificial noise arriving at the legal receiver is beneficial to the demodulated signal of the legal receiver.Through simulation analysis,compared with the existing methods,the method can effectively limit the illegal eavesdropping side to steal information,and improve the Singal to Noise Ratio (SNR) of the legal receiving end,and significantly improves the security performance of the system.Secondly,another key technique of antenna selection(AS)in physical layer security is researched.In order to solve the problem of insufficient secure capacity of existing secure transmission methods based on random antenna selection,an improved optimal method is proposed.A safe transmission method for antenna selection,the transmitter of the method selects several transmit antennas corresponding to the sub-channels with the highest gain according to the status of the legitimate channel,and uses them to transmit signals,so that the legal receiver can obtain higher signals when receiving signals.The choice of gain.Through simulation analysis,compared with the existing methods,this method can effectively increase the security capacity of the system,improve the symbol error rate performance of the legitimate receiver,and effectively improve the system's security performance.