论文标题
智能反射表面辅助MMWave和Terahertz系统的安全传输
Secure Transmission for Intelligent Reflecting Surface-Assisted mmWave and Terahertz Systems
论文作者
论文摘要
这封信的重点是智能反射表面（IRS）辅助毫米波（MMWave）和Terahertz（THZ）系统的安全变速箱，在该系统中，在被动窃听器的情况下，基站（BS）通过IRS与目的地进行通信。为了最大化系统保密速率，通过发射功率和离散的相移约束共同优化了BS处的发射光束和IRS的反射矩阵。首先证明，波束形成设计独立于排名一通道假设下的相移设计。然后将配方的非凸问题转换为两个子问题，这些问题可以解决。具体而言，提出了在BS处发射光束形成的封闭式溶液，并提出了基于元素的方法（SDP）基于元素的方法和基于元素的块坐标下降（BCD）的方法来设计反射矩阵。理论上分析了我们提出的方法的复杂性。模拟结果表明，所提出的IRS辅助策略可以显着提高保密率的性能，而不论窃听的位置如何（靠近或阻止机密束）。
This letter focuses on the secure transmission for an intelligent reflecting surface (IRS)-assisted millimeter-wave (mmWave) and terahertz (THz) systems, in which a base station (BS) communicates with its destination via an IRS, in the presence of a passive eavesdropper. To maximize the system secrecy rate, the transmit beamforming at the BS and the reflecting matrix at the IRS are jointly optimized with transmit power and discrete phase-shift constraints. It is first proved that the beamforming design is independent of the phase shift design under the rank-one channel assumption. The formulated non-convex problem is then converted into two subproblems, which are solved alternatively. Specifically, the closed-form solution of transmit beamforming at the BS is derived, and the semidefinite programming (SDP)-based method and element-wise block coordinate descent (BCD)-based method are proposed to design the reflecting matrix. The complexity of our proposed methods is analyzed theoretically. Simulation results reveal that the proposed IRS-assisted secure strategy can significantly boost the secrecy rate performance, regardless of eavesdropper's locations (near or blocking the confidential beam).
