Low Complexity Artificial Noise Aided Beam Focusing Design in Near-Field Terahertz Communications

TL;DR

This paper proposes a low-complexity artificial noise aided beam focusing scheme for near-field terahertz communications, enhancing secrecy rate by optimizing beam focus and power allocation against eavesdroppers.

Contribution

It introduces a novel low-complexity beam focusing method with artificial noise for secure near-field terahertz communications, optimizing secrecy performance.

Findings

Significant secrecy rate improvement with the proposed scheme

Effective mitigation of eavesdropper's information leakage

Enhanced performance when eavesdropper is closer to the BS

Abstract

In this paper, we develop a novel low-complexity artificial noise (AN) aided beam focusing scheme in a near-field terahertz wiretap communication system. In this system, the base station (BS) equipped with a large-scale array transmits signals to a legitimate user, while mitigating information leakage to an eavesdropper. We formulate an optimization problem to maximize the secrecy rate achieved at the legitimate user and solve it by designing the optimal beam focusing and power allocation. Numerical results demonstrate the significant performance improvement achieved by the proposed AN aided beam focusing scheme, especially when the eavesdropper is located closer to the BS than the legitimate user.