On Enhancing Secrecy Performance For Wireless Communications Via Artificial Noise

The daily life and communication of contemporary people are closely related to wireless transmissions all the time.Under the huge military and civil market demands,wireless communication technology has developed rapidly and deeply,and this trend will definitely not stop developing.In recent years,with the development and employment of 5G technique,the popularity of wireless communication has been further promoted.At the same time,wireless communication is also an indispensable part of many fashionable technologies and projects,such as the Internet of Things,unmanned vehicle,intelligent home,and smart city.With the advancement and realization of the Internet of everything and the interoperability of all things,the number and types of nodes in wireless networks are exploding.How to enhance the security of information transmission and ensure efficient and reliable operations in wireless communication systems has become major research difficulty and hotspot.The physical layer security scheme can directly utilize the randomness nature of wireless channels to enhance the secrecy performance of wireless transmission networks and is widely recognized as a promising technology which can complement even replace the traditional key-based encryption method.Artificial noise jamming technology is a promising candidate able to improve the secrecy performance of wireless communications at the physical layer.In this paper,the application of artificial noise jamming in wireless transmissions is explored and analyzed in details.Three important scenarios are studied and analyzed: the application of artificial noise in full-duplex multiple-antenna destination-based jamming system,artificial noise aided precoding in full-duplex relaying networks and artificial noise jamming in UAV-aided wireless communications.Two common channel models are considered,namely,the Rayleigh fading channel and the Nakagami-m fading channel.The impacts of imperfect channel state information of legitimate link and two kinds of eavesdropping channel state information on particular wireless networks are explored.The related formulas of ergodic achievable secrecy rate and secrecy outage probability are derived.A flexible approximation method called Gauss-Laguerre Quadrature for calculating the closed-form expressions of necessary secrecy performance metrics is given.A two-step joint optimization scheme which can optimize the system's achievable secrecy rate is designed,and the closed-form expression of optimal power allocation factor as well as the optimal antenna mode switching scheme are deduced.The secrecy performances in the case of large-scale antenna array and the asymptotic secrecy performance under several extreme conditions are analyzed.Finally,Monte Carlo simulations verify the correctness and effectiveness of secrecy performance analysis and optimization.The research results show that artificial noise jamming technology is an effective physical layer security method via the secrecy performance analysis,and the applicable scenarios are quite inclusive.Through reasonable system optimization design,the secrecy performance of artificial noise jamming technique in wireless communication systems can be greatly improved.