Roaming in Connecting Light
Given the growing interests on using Commercial Off-The-Shelf (COTS) devices to implement Visible Light Communication (VLC) systems, there is a call for filling the gap between VLC standards and practical deployments. In particular, since LED-Camera VLC systems have shown a strong potential in covering large indoor areas due to the increasing pervasiveness of LED lighting systems and smartphones, providing roaming support to such a system has become an impending need. To this end, we propose RoCLight as a lightweight solution to this call. In order to have a proper feedback channel for roaming support, we innovate in converting part of the LED luminaires (already used as the VLC transmitters) into light sensors. By sensing the disturbance to the ambient diffuse reflection caused by user presence and mobility, RoCLight is able to adaptively handoff its transmissions from one luminaire to another, so as to keep up with user mobility and hence to offer an adequate roaming support. We implement RoCLight as a small-scale testbed with five LED luminaires spanning a length of 7.5 meters, and we conduct various evaluations on the roaming support capability of RoCLight based on this testbed; all our experiment results strongly demonstrate its promising performance.