Secrecy Rate Maximization for Indoor Multi-Color VLC Systems

Visible light communication (VLC) is a wireless optical communication technology that aims to achieve simultaneous ambient lighting and communication by utilizing light sources used for illumination to transmit data. Although indoor VLC systems are considered to have high data security due to the inability of light to pass through walls, data security is emerging as a critical need for VLC systems in common-use areas such as hospitals and shopping malls. In this regard, physical layer security (PLS), which enables secure data communication by exploiting the physical characteristics of the communication channel, is one of the current topics being addressed in the literature to ensure data security in VLC systems. In this paper, we focus on maximizing the secrecy rate (SR) in multi-color (MC) VLC systems. For this purpose, beamforming vectors that maximize SR, considering the widely used zero-forcing (ZF) and artificial noise (AN) PLS methods, were obtained using the particle swarm optimization (PSO) algorithm. The results indicate that the beamforming vectors obtained using PSO for the considered MC-VLC system increase SR compared to traditional ZF and AN methods.