In this paper, we investigate the secrecy performance of a single-input single-output visible light communication (VLC) channel in the presence of an eavesdropper. The studied VLC system comprises distributed light-emitting diodes (LEDs) and multiple randomly located users (UEs) within an indoor environment. A sum secrecy rate maximization problem is formulated to enhance confidential transmission by selecting the optimal LED for each UE. To address the non-convex and non-continuous nature of this problem, we propose a tabu search-based algorithm that prevents entrapment in local optima by organizing the trial vectors from previous iterations. Furthermore, we develop three straightforward LED selection strategies that reduce computational complexity by employing fixed criteria to choose one LED for each UE. We also examine the convergence and complexity analysis of the proposed algorithm and strategies. The results demonstrate that the secrecy performance of our proposed algorithm is very close to the global optimal value and surpasses that of the developed strategies.

翻译：本文研究了在存在窃听者的情况下，单输入单输出可见光通信（VLC）信道的安全性能。所研究的VLC系统由分布式发光二极管（LED）和室内环境中随机分布的多个用户（UE）组成。为增强保密传输，提出了一个总保密速率最大化问题，旨在为每个UE选择最优LED。针对该问题的非凸且非连续特性，本文提出一种基于禁忌搜索的算法，通过组织前序迭代中的试探向量避免陷入局部最优。此外，我们开发了三种简化的LED选择策略，采用固定准则为每个UE选择单一LED以降低计算复杂度。同时考察了所提算法与策略的收敛性和复杂度分析。结果表明，本文算法的保密性能非常接近全局最优值，且优于所开发的简化策略。