Cooperative Load Balancing in Hybrid Visible Light Communications and WiFi

As a complementary extension of established Radio Frequency (RF) Wireless Local Area Networks (WLANs), Visible Light Communication (VLC) using commercially available Light-Emitting Diode (LED) transmitters offers a huge data rate potential in this license-free spectral domain, whilst simultaneously satisfying energy-efficient illumination demands. Various VLC cell formations, ranging from a regular cell-layout associated with different Frequency Reuse (FR) patterns to merged cells by employing advanced transmission scheme are investigated. Furthermore, a hybrid Down-Link (DL) offering full RF-coverage by a WLAN and additionally supported by the abundant spectral resources of a VLC network is studied. Cooperative Load Balancing (LB) achieving Proportional Fairness (PF) is implemented by using both centralized and distributed resource-allocation algorithms. The performance of this hybrid RF/VLC system is analysed both in terms of its throughput and fairness in diverse cell formation scenarios. Our simulation results demonstrate that, the VLC system advocated is capable of providing a high Area Spectral Efficiency (ASE) and our hybrid RF/VLC system achieves the highest throughput and the highest grade of fairness in most of the scenarios considered.