Low Complexity Physical Layer Security Schemes Based on Channel Characteristics of Near-Field XL-MIMO Systems: A Survey

Extremely large-scale multiple-input and multiple-output (XL-MIMO) is one of the most promising key technologies for the coming sixth generation wireless communications. Considering passive eavesdropping threats, the influence of near-field channel characteristics of uplink multi-user XL-MIMO systems on the physical layer security schemes are analyzed in this paper. Then, a comprehensive survey of physical layer encrypted methods and low complexity detection methods is presented. Conclusively, it is pointed out that the study on low complexity and high reliability modulation encrypted methods based on near field channel characteristics for uplink multi-user XL-MIMO systems has very important research value for the next generation's green security communications. Some corresponding future potential research works for low complexity physical layer security schemes based on channel characteristics of near-field XL-MIMO systems are also presented in this paper.