He Yuqian, Zhang Lu, Liu Shanyun, Zhang Hongqi, Yu Xianbin
College of Information Science and Electronic Engineering, Zhejiang University, Hangzhou 310027, China.
Zhejiang Lab, Hangzhou 310000, China.
Micromachines (Basel). 2022 Aug 12;13(8):1300. doi: 10.3390/mi13081300.
The terahertz (THz) band is expected to become a key technology to meet the ever-increasing traffic demand for future 6G wireless communications, and a lot of efforts have been paid to develop its capacity. However, few studies have been concerned with the transmission security of such ultra-high-speed THz wireless links. In this paper, we comprehensively investigate the physical layer security (PLS) of a THz communication system in the presence of multiple eavesdroppers and beam scattering. The method of moments (MoM) was adopted so that the eavesdroppers' channel influenced by the PEC can be characterized. To establish a secure link, the traditional beamforming and artificial noise (AN) beamforming were considered as transmission schemes for comparison. For both schemes, we analyzed their secrecy transmission probability (STP) and ergodic secrecy capacity (ESC) in non-colluding and colluding cases, respectively. Numerical results show that eavesdroppers can indeed degrade the secrecy performance by changing the size or the location of the PEC, while the AN beamforming technique can be an effective candidate to counterbalance this adverse effect.
太赫兹（THz）频段有望成为满足未来6G无线通信不断增长的流量需求的关键技术，并且已经付出了很多努力来开发其容量。然而，很少有研究关注这种超高速太赫兹无线链路的传输安全性。在本文中，我们全面研究了存在多个窃听者和波束散射情况下太赫兹通信系统的物理层安全（PLS）。采用矩量法（MoM）来表征受理想电导体（PEC）影响的窃听者信道。为了建立安全链路，将传统波束成形和人工噪声（AN）波束成形作为传输方案进行比较。对于这两种方案，我们分别分析了它们在非勾结和勾结情况下的保密传输概率（STP）和遍历保密容量（ESC）。数值结果表明，窃听者确实可以通过改变PEC的大小或位置来降低保密性能，而AN波束成形技术可以成为抵消这种不利影响的有效候选方案。
