Dynamic Beam Clustering for Grid-of-Beam Multi-User Access in 6G LiFi Networks

The next generation of light fidelity (LiFi) networks will be based on laser-based optical wireless communication (OWC) to meet the demands for multi-Gigabit/s (<tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\text{Gb} / \mathrm{s}$</tex>) per user data rates. In this paper, we consider a double-tier access point (AP) architecture using an array of arrays of vertical cavity surface emitting lasers (VCSELs) to provide grid-of-beam (GoB) multi-user access for sixth generation (6G) laser-based optical wireless networks. In particular, we develop a novel dynamic beam clustering (DBC) algorithm based on graph theory with the aim to perfectly cancel inter-cluster interference (ICI) by dynamically adapting the clustering strategy according to network variations. We then carry out performance analysis for key performance metrics including the multi-user sum rate and fairness, as well as energy efficiency (EE). Simulation results demonstrate remarkable performance gains of DBC with respect to static beam clustering (SBC) strategies using fixed cluster sizes especially in terms of the sum rate and EE.