Research On Security Performance Of Multi-Antenna Diversity System

The openness of the wireless transmission medium makes it easy for eavesdropping users to intercept signals transmitted by both parties.The use of physical layer security technology to ensure secure communication has become a hot research topic in wireless communication systems.The core of the physical layer security technology is to utilize the physical characteristics such as fading and noise of the wireless channel,so that the information entropy of the security information obtained by the legitimate receiver is greater than the information entropy obtained by the potential eavesdropper,thereby causing distortion of the eavesdropping channel transmission and making eavesdropping.Multi-antenna technology occupies an important position in wireless communication,so it is of great value and significance to study the physical layer security technology in multi-antenna systems.Aiming at the diversity technology in multi-antenna eavesdropping system,the main research contents of this thesis are summarized as follows:(l)Based on the multi-antenna selection system,the transmit antenna selection/receive antenna selection security transmission scheme and the transmit antenna selection/maximal ratio combining security transmission are studied,the theoretical analysis models of the two schemes are derived respectively.The simulation results show that the multi-antenna selection system can make full use of the multipath effect to improve the diversity gain,which will have higher security performance than the single antenna system.(2)For the multi-antenna eavesdropping system model in the physical layer security problem,the paper studies a secure transmission scheme maximum ratio transmission and maximum ratio combining.By deducing the security performance expressions of multi-antenna systems,including the probability of nonzero secrecy capacity,the secrecy outage probability and the ergodic secrecy capacity,the analysis results show that the increase of the number of antennas at the transmitter and the average signal-to-noise ratio of the main channel can improve the security performance of the system.