Research On Physical Layer Security Technology Based On Massive MIMO

With the rapid increase in the number of mobile phone users,service types and demands of mobile communication are getting diverse.Communication technology has made great progress nowadays and mobile communication has experienced the technical change from 2G to 5G.Due to the inherent open nature of wireless communication channels,the mobility of mobile communication terminals and the uncertainty of user distribution,etc.,wireless communication systems are faced with many security risks and threats.In order to ensure that the signal can be sent from sender to receiver safely and reliably,the traditional method is based on cryptography.With the help of the secure transport protocol in the upper layer network,the secure transmission of information is ensured.However,with the increasing computing power of devices and the more frequent exchange of information among users in the network,the secret-based computational complexity has gradually failed to meet the security needs of people for future mobile communications.The research of physical layer security which based on physical layer characteristics came into being.The purpose of this thesis is to apply the precoding technology in physical layer security technology to large-scale MIMO system and provide a method to improve the secure transmission rate in large-scale MIMO networks and the corresponding analysis of confidential energy efficiency.The main contents of this thesis are listed as below,1.Secure transmission is studied in multi-cell massive multiple-input multiple-output(MIMO)downlink system with linear precoding and imperfect channel state information(CSI)under the large scale limit,in which the confidential message transmitted to the intended user can be eavesdropped by both the users in the same cell and the users in the adjacent cell.2.The secrecy transmit rate of the single-cell massive MIMO downlink system with artificial noise and linear precoding has been studied in this thesis and we use a metric named secrecy energy efficiency(SEE),which means the amount of bits which can be reliably and confidentially transmitted per Joule of consumed energy,to evaluate the performance of the system.The purpose of this thesis is to study the use of physical layer security techniques in downlink Massive MIMO communication system and the secrecy energy efficiency concept in network to increase the secrecy transmit rate of the system.