Design of Artificial Noise for Physical Layer Security in Visible Light Systems with Clipping

TL;DR

This paper investigates how to design artificial noise in visible light communication systems to improve security, considering the effects of clipping distortion caused by LED constraints, and proposes a sub-optimal solution approach.

Contribution

It introduces a novel artificial noise design method accounting for clipping distortion in VLC systems, enhancing physical layer security.

Findings

Clipping distortion significantly reduces secrecy levels.

Artificial noise improves security compared to no-AN schemes.

The proposed method effectively mitigates clipping effects.

Abstract

Though visible light communication (VLC) systems are contained to a given room, ensuring their security amongst users in a room is essential. In this paper, the design of artificial noise (AN) to enhance physical layer security in VLC systems is studied in the context of input signals with no explicit amplitude constraint (such as multicarrier systems). In such systems, clipping is needed to constrain the input signals within the limited linear ranges of the LEDs. However, this clipping process gives rise to non-linear clipping distortion, which must be incorporated into the AN design. To facilitate the solution of this problem, a sub-optimal design approach is presented using the Charnes-Cooper transformation and the convex-concave procedure (CCP). Numerical results show that the clipping distortion significantly reduces the secrecy level, and using AN is advantageous over the no-AN scheme in improving the secrecy performance.