Research On Physical Layer Security Technology For Future Network Information Protection

Wireless channels have a natural openness that makes interconnected communication very convenient,but it also leads to a wireless communication system that is very vulnerable to security threats.Eavesdroppers can take advantage of the broadcast characteristics of wireless channels to easily intercept BS information transmitted to the user,resulting in the leakage of important data.At the same time,malicious attackers can also send jamming signals to interfere with the reception of information from legitimate users,degrading the quality of the received signals at the legitimate users and greatly affecting the normal operation of the wireless communication system.In order to solve these problems,physical layer security technology has emerged.This technology utilizes the random characteristics of the wireless channel between different users,and eliminates the natural loopholes of the wireless channel by applying pre-coding and other technical means,so as to enhance the security of the system.Compared with the traditional high-level key encryption technology,the physical layer security technology pays more attention to the statistical characteristics of the channel between devices during the information transmission process,so as to resist potential threats such as possible eavesdroppers at the physical layer.Based on the above considerations,this thesis aims to develop the research of physical layer security technology around future information networks.Aiming at the potential network security threats under different application scenarios of future diversified networks,this thesis proposes a scheme of joint optimization of beamforming and introduction of AN.Meanwhile,in the downlink transmission process,this thesis also proposes technical solutions such as user and AP security classification,which can effectively eliminate the problem of information redundancy,ensure the security of information in wireless communications,and provide new ideas for the rational deployment of communication facilities such as BS and trusted relay.The main contributions and innovations of this thesis are summarized as follows:1)In this study,we first propose a secure transmission scheme for the physical layer assisted by collaborative relaying.The scheme improves the security of the wireless communication system by introducing relay nodes to realize collaborative communication.In this thesis,a machine learning network is deployed at the relay end as well as the receiver end to statistically learn the global channel state information in the wireless communication system,so as to design an optimal secure beamforming scheme,which can effectively inhibit the eavesdropping of the transmitted information by eavesdroppers.Second,in order to prevent the emergence of malicious relay nodes,IRS is introduced as a trusted relay node,and an efficient and reliable collaborative relay transmission scheme is proposed to strengthen the security of the wireless communication system at the physical layer,so as to effectively prevent security threats such as eavesdropping,jamming,and tampering.2)This thesis proposes a IRS-assisted physical layer secure transmission scheme based on user classification.Based on the trusted relay IRS-assisted wireless communication system mentioned in the previous chapter,the communication users in the network are categorized according to their security,which reduces the unnecessary security operations of the users who do not have the need for secure communication,and thus reduces the extra energy consumption at the base station.During downlink transmission,this thesis classifies the users into two categories:one is the secure users who have the need for secure communication,and the other is the ordinary users who only need simple communication.Different secure transmission strategies are adopted for these two types of users,which satisfy the different communication needs of the users,and also realize the goal of energy saving and emission reduction,and promote green communication.This solution is not only applicable to IRS-assisted systems,but also provides a solution for new types of networks in the future.3)In this thesis,we propose a secure transmission scheme for downlink of CF network based on AP classification.The distributed deployment of CF network can effectively solve the frequent switching of users at the cell edge as well as the interference problem,and it is a key necessary technology to realize the "resource-centric" to "user-centric".Unlike the traditional approach in which all AP transmit information and AN simultaneously,this thesis classifies AP into two categories:IAP,which is responsible for transmitting information,and NAP,which is responsible for transmitting AN,in order to guard against the leakage of information as well as to inhibit the possible existence of active eavesdropping.This scheme is of great significance to the future wireless communication security field and provides a new solution to the problem of information leakage and eavesdropping.4)Based on the research of the above work,this thesis proposes a downlink secure transmission scheme for future CF networks using a new type of covert communication.By introducing AN,the covert communication makes the power spectrum of AP similar to the normal background noise,so as to confuse the transmission of the communication link,and at the same time,it can mask the source of the information,so that it is difficult for eavesdroppers to determine the location of the transmitter.In this thesis,beamforming and AN design are used to achieve covert transmission and maximize the data rate in the complex environment of IoT,which provides new ideas for the design of future CF scenarios in IoT networks and promotes the further development of IoT technology.