A Secure Link Adaptation in an Indoor Heterogeneous VLC/RF Network

In this paper, we consider an indoor environment where both visible light communication (VLC) and radio frequency (RF) networks are co-deployed. A source transmitter can use either a VLC-link or a RF-link to transmit the information to the legitimate user and we assume that an eavesdropper is also present to intercept the legitimate information transmission. Here, VLC network is considered as a primary network and RF network is used as a backup. Therefore, a source transmitter utilizes the RF-link only when VLC-link offers negative secrecy-rate for legitimate information transmission. In particular, we propose a secrecy-rate based secure link adaptation mechanism to select the RF-link. We derive the exact closed-form expressions for secrecy outage probability and system secrecy outage probability, and further, observe the effect of various physical parameters on security performance analysis.