A tabu search-based LED selection approach safeguarding visible light communication systems

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.