Research And Simulation Of Physical Layer Security Based On Artificial Noise And Randomized Weighting In Cooperative Relay System

As a kind of important method of wireless communication,satellite communication has been widely used in military and civil fields.However,with its weakness of long communication distance,large channel fading and some character of wireless channel such as openness,the satellite communication system is vulnerable to malicious eavesdropper.Therefore,The wireless communication technology to protect the safety of satellite communication has been one of the most important research field of the wireless communication.As a sort of new direction of security technology,physical layer security technology has unique advantages and features so that can be applied to the study of satellite communication system.In view of long communication distance and large channel fading of satellite communication system,cooperative relaying technique was used to obtain the cooperative diversity gain,then against channel fading effectively and improve the channel quality of main channel of communication system.The existing cooperative relay system has low utilization rate of relay nodes and don't take problem of unlikelihood of relay nodes.So the packet relay mechanism was used to divide relay nodes as cooperative forwarding group and collaborative interference group,which can gain large packet gains by sacrificing little cooperative diversity gain then improve the utilization rate of the relay nodes.In order to reduce the channel quality of the communication system,the zero space artificial noise and the random weighting technique were used to disturb the malicious eavesdropping node to the confidential information artificially.In view of the limitation of existing random weighting techniques 'that is subjected to constant modulus constraint limits,random weighting coefficient vector was selected based on state informational difference of main channel and wiretap channel and was used to do random weighting to confidential information.The zero space artificial noise transmitted by the cooperative interference group can prevent the eavesdropping of the random weighting system from the.malicious eavesdropping node and then to ensure the security of communication further.The overall scheme of the system maximizes the difference between the main channel and the eavesdropping channel,and can obtain the large security capacity then realize the security communication of information.Simulation and analysis of the proposed scheme based on MATLAB simulation shows that the scheme can effectively disturb eavesdropping then improve the security capacity of the communication system and lower bit error rate of the communication system,furthermore,optimizes the transmission performance and security of the communication system,prevents eavesdropping of satellite communication system.