Physical-Layer Security for Indoor Visible Light Communications: Secrecy Capacity Analysis

Abstract

This paper investigates the physical-layer security for an indoor visible light communication (VLC) network consisting of a transmitter, a legitimate receiver and an eavesdropper. Both the main channel and the wiretapping channel have nonnegative inputs, which are corrupted by additive white Gaussian noises. Considering the illumination requirement and the physical characteristics of lighting source, the input is also constrained in both its average and peak optical intensities. Two scenarios are investigated: one is only with an average optical intensity constraint, and the other is with both average and peak optical intensity constraints. Based on information theory, closed-form expressions of the upper and lower bounds on secrecy capacity for the two scenarios are derived. Numerical results show that the upper and lower bounds on secrecy capacity are tight, which validates the derived closed-form expressions. Moreover, the asymptotic behaviors in the high signal-to-noise ratio (SNR) regime are analyzed from the theoretical aspects. At high SNR, when only considering the average optical intensity constraint, a small performance gap exists between the asymptotic upper and lower bounds on secrecy capacity. When considering both average and peak optical intensity constraints, the asymptotic upper and lower bounds on secrecy capacity coincide with each other. These conclusions are also confirmed by numerical results.Index Terms-Gaussian noise, physical-layer security, secrecy capacity, visible light communications.

On the Secrecy Performance of Random VLC Networks With Imperfect CSI and Protected Zone

“…By considering the imperfect CSIR, the randomly deployed receivers and protected zone for VLC, the instantaneous secrecy capacity (SC) cannot be used to evaluate the system performance. Based on the derived instantaneous SC result in our previous work [16], the ASC will be analyzed to evaluate the secrecy performance. Moreover, some insights will also be provided.…”

“…In our previous work [16], tight lower and upper bounds on the instantaneous SC for indoor VLC has been derived. Without loss of generality, a lower bound on the instantaneous SC in [16] is employed to analyze the ASC, which is shown in the following Lemma.…”

“…By using the variational method, an improved input distribution can be obtained [4]. By employing the variational method, three lower bounds of secrecy capacity for VLC are obtained in [15], where the upper bounds are obtained in [16]. Note that refs.…”

On the Secrecy Rate of Spatial Modulation-Based Indoor Visible Light Communications

“…However, the discrete input distribution is still sub-optimal. To further improve secrecy performance, a better input distribution was obtained in [29]. Focusing on a hybrid VLC/RF communication system with energy harvesting, the secrecy outage probability (SOP) was analyzed in [30].…”

“…• The secrecy rate for SM based VLC with non-negativity and average optical intensity constraints is analyzed. By using the uniform selection (US) scheme and the existing results [29], a lower bound on secrecy rate is derived. According to the dual expression of secrecy rate, an upper bound of the secrecy rate is obtained.…”