Performance Analysis And Verification Of Network-Coding-Based Physical Layer Secure With Imperfect CSI

Wireless communication technology has been widely used benefiting from its numerous advantages with its rapid developments in recent years.However,the data transmission may also be vulnerable to eavesdropping because of the openness,broadcasting and mobility of wireless channels.Physical layer security technology exploits the uniqueness and difference of wireless channel to establish a security mechanism so as to realize the secure transmission of information.An important prerequisite to ensure secure transmission is that the transmitter knows perfect channel state information(CSI)in physical layer secure transmission.However,it is difficult for the transmitter to obtain the perfect CSI in advance,due to the imperfect factors such as feedback delay or estimation error in real communication environment,which will reduce to some extent the practical reference value of the physical layer security research based on the perfect CSI.Considering the problems above-mentioned,this thesis studies the secure transmission of physical layer with imperfect CSI.The research results are as follows:1)The thesis studies physical layer security with imperfect CSI combining the network coding technology and relay technology.Focusing on the relay secure transmission model based on the two-slot analog network coding and the three-slot network coding,we analyze the specific process of transmitting and receiving signals of each node in Rayleigh fading channel.The security capacity of legitimate users and the secrecy outage probability with imperfect CSI are also given.2)A hardware verification platform is designed and established for relay secure transmission model based on three-slot network coding.According to the characteristics of the model,the hardware platform is divided into three parts: the terminal hardware,the OFDM transceiver system and the network coding module.The performance of secure communication on the verification platform is also given.3)Focusing on the problem of node synchronization caused by the processing delay between nodes,the accuracy and clock difference between different devices,we propose a three-node self-synchronization transmission scheme.By effectively utilizing the broadcast slot of the relay node the proposed scheme can realizes the slot synchronization without any additional hardware cost.4)Focusing on the low efficiency caused by baseband data processing delay,we propose an efficient data transmission scheme against this processing delay.Via the slot allocation,the scheme can improve the communication efficiency by compressing the slot fragments to alleviate the baseband signal processing delay.