Experimental Evaluation of an Indoor Visible Light Communications System in Light Dimming Conditions

Visible Light Communications (VLC) are a new wireless communications technology that benefits from numerous advantages. Nevertheless, due to particular limitations, its deployment is still not in sight. A specific VLC challenge is establishing the link when the transmitter needs to provide light dimming function or even when it is in off-state. To achieve this goal, a new indoor VLC prototype was developed and experimentally evaluated. The VLC transmitter has been developed as part of the indoor lighting infrastructure, whereas the VLC receiver is being developed as part of a smart backpack for visually impaired persons’ assistance. The prototype has been evaluated in light dimming conditions, going down to 1% duty cycle, which is perceived by the human eye as almost in an off-state. The experimental results demonstrate the feasibility of the concept, as a BER lower than $10^{-6}$ can be maintained while decreasing the light intensity down to the point where the light seems totally off.