Proactive Handover Mechanism for Blockage Avoidance in Indoor VLC Networks

Handover management in Visible Light Communications (VLC) networks is an open issue due to the need of maintaining alignment between a transmitting Light Emitting Diode (LED) and a receiver PhotoDetector (PD). Mobility strongly affects VLC connectivity links, as well as occlusions that may obstruct the Line-of-Sight (LoS) propagation. In this paper we present a proactive handover solution, which is able to switch connectivity links from a serving VLC “lighting” cell to a candidate one, in case of blockage that affects the VLC link. Differently from conventional handover mechanisms, where a handover is trigged by quality of service metrics or localization information, our technique is dedicated to VLC networks which can be affected by occlusions causing blockages. The proposed approach has been implemented both in hard and soft mode, and assessed in terms of achievable data rate and hand over latency for a user walking in a given reference room at different speeds.