Hybrid radio-visible light downlink performance in RF sensitive indoor environments

Visible light communications (VLC) is an emerging technology for indoor wireless networks which uses unregulated visible spectrum in the optical range. Since it is safe to use visible light as communication medium in radio frequency (RF) prone environments, VLC may provide harmless downlink connectivity in such scenarios. In this paper, we analyze an indoor RF sensitive environment where RF propagation is blocked intentionally and the downlink is provided through a VLC network. However, this indoor VLC network is connected to the outside world through a relay using an RF wireless link to a base station. Hence, a hybrid radio-visible light wireless link enables the base station to reach the end users. The relay amplifies the received signal from the base station and modulates it onto the intensities of the optical transmitters which provide the indoor coverage. Due to several transmitters, user nodes may receive multiple line of sight signals resulting in a multi-tap channel. We investigate this indoor optical channel and propose a statistical model that fits in this situation. We use the proposed model to derive the expressions for outage probability of the hybrid downlink.