  Visible light communication (VLC) has wide unlicensed bandwidth, enables
communication in radio frequency (RF) sensitive environments, realizes
energy-efficient data transmission, and has the potential to boost the capacity
of wireless access networks through spatial reuse. On the other hand, WiFi
provides more coverage than VLC and does not suffer from the likelihood of
blockage due to the light of sight (LOS) requirement of VLC. In order to take
the advantages of both WiFi and VLC, we propose and implement two heterogeneous
systems with Internet access. One is the hybrid WiFi-VLC system, utilizing
unidirectional VLC channel as downlink and reserving the WiFi back-channel as
uplink. The asymmetric solution resolves the optical uplink challenges and
benefits from the full-duplex communication based on VLC. To further enhance
the robustness and increase throughput, the other system is presented, in which
we aggregate WiFi and VLC in parallel by leveraging the bonding technique in
Linux operating system. Online experiment results reveal that the hybrid system
outperforms the conventional WiFi for the crowded environments in terms of
throughput and web page loading time; and also demonstrate the further improved
performance of the aggregated system when considering the blocking duration and
the distance between access point and user device.
