This manuscript is currently under submission to Journal of Optical Communications and Networking. The abstract of the paper is as follows:

Light fidelity (LiFi) is an emerging wireless networking technology of visible light communication (VLC) paradigm for multiuser communication. This technology enables high data rates due to the availability of large visible light spectrum. While current studies have shown the potential for LiFi technology, they borrow the MAC layer protocols from traditional WiFi. However, a number of prior studies have shown the challenges faced by the MAC layer of WiFi in the presence of large number and types of devices. In this work, we show that hybrid coordination function controlled access (HCCA) MAC protocol in LiFi provides higher throughput than the traditional  carrier sense multiple access with collision avoidance (CSMA/CA) mechanism to user devices. We also show that HCCA has the limitation of higher message overhead in the presence of large number of devices. We utilize both theoretical analysis and extensive simulations to study these performance tradeoffs and identify a threshold when a LiFi access point should switch to HCCA from CSMA/CA and vice-versa. Finally, based on our findings, we design a hybrid MAC mechanism that switches between HCCA and CSMA/CA based on the number and type of devices present. Our evaluation shows that this hybrid mechanism can outperform both HCCA and CSMA/CA individually in the presence of different number of devices.