Research On Physical Layer Security Technology Of Massive MIMO Uplink

As one of the key technologies of 5G,Massive Multiple-Input Multiple-Output technology was proposed,which greatly improved the throughput of communication systems.Therefore,it has been extensively studied by scholars at home and abroad.The physical layer security of Massive MIMO system is one of the research hotspots.In the research on the physical layer security of massive MIMO systems,a large amount of literature focuses on how to ensure the secure transmission of the downlink.Although there are few literatures concerned with the security of the uplink transmission,it is equally important.In this article,we prove that by performing channel estimation in the training phase and coherent detection in the data transmission phase,multi-antenna eavesdroppers may severely reduce the confidentiality rate of legal communications.In order to ensure the security of the legal communication in the uplink of the massive MIMO system,from the perspective of artificial noise against uplink eavesdropping,the following works are mainly carried out:(1)This paper first briefly expounds the background and significance of the research direction of this paper,then introduces the advantages of large-scale MIMO technology and the presence of physical layer safety related issues,followed by the status quo of physical layer security under large-scale MIMO system,finally introduced the physical layer security related theory.(2)This paper proposes a method in the uplink data transmission phase: the artificial noise scheme is added to combat uplink multi-antenna eavesdropping.In addition,based on the proposed artificial noise scheme,the uplink legal communication capacity bounds,eavesdropping communication capacity bounds and security capacity bounds are studied,and then under two different detection strategies,MRC and ZF,the influence of artificial noise scheme on system security performance is studied.Finally,the security performance of the system is analyzed by combining parameters such as the number of antennas with different detection strategies.(3)Based on the artificial noise-assisted secure transmission scheme proposed in this paper,from the perspective of maximizing the confidentiality rate,the optimization problem of power allocation between AN and data symbols is further proposed.At first,the optimal power allocation strategy in two different situations is studied,that is,the base station and the eavesdropper know the channel state information of the user,and the other is the opposite.Second,in each case,further consideration is given to whether the user knows the exact location of the eavesdropper.Then the influence of non-ideal factors(including channel estimation error and the uncertainty of eavesdropper's location)on the power allocation strategy is discussed.Finally,a large number of simulations were carried out to verify the effectiveness of our proposed scheme.