Exploiting EDCA for Feedback Channels in Hybrid VLC/WiFi Architectures

In this paper, we consider integrating VLC and WiFi technologies in a scenario in which Light-Emitting-Diodes (LEDs), acting as network access points (APs) for ultra-dense Internet of Things applications, are deployed into an indoor lighting infrastructure. In such a scenario, RF-links can be exploited for complementing VLC-links in dealing with mobility and bidirectional communications, which can be problematic due to the limited coverage areas and self-generated interference of VLC APs. In particular, we consider the possibility of supporting a technology-based duplexing scheme, in which downlink and uplink transmissions are performed by means, respectively, of VLC and WiFi interfaces integrated into the same node. In order to fully exploit the VLC bandwidth in the presence of background WiFi traffic and multiple coexisting VLC links, we discuss the importance of adopting a prioritization mechanism based on EDCA, as well as frame aggregation, for the uplink channel of the integrated architecture. Our considerations are corroborated by numerical results based on NS-3 simulations and a real simple experiment.