Design and Implementation of a Hybrid RF-VLC System with Bandwidth Aggregation

Visible light communication (VLC) has the potential to add significant capacity to short range wireless access technology by piggybacking data on light from overhead luminaires. However, an uplink is required to complete such a network, which introduces new issues. In this paper, we propose and implement a practical hybrid WiFi-VLC system that does not require a separate VLC uplink but rather aggregates WiFi and VLC downlinks and shares the WiFi uplink. Aggregated downlink bandwidth of the hybrid system is achieved by using a Linux bonding driver and media access control (MAC) address redirection. The throughput of the system is tested and compared with WiFi-only (one WiFi downlink) and asymmetric (one VLC downlink) systems under a congested WiFi environment. The evaluation results show that our system achieves aggregated downlink bandwidth that is approximately the summation of the downlink capacities of the WiFi-only and asymmetric systems. The study of the round-trip time (RTT) demonstrates the tradeoff between bandwidth utilization and latency that can be used in the design of load-balancing algorithms. Finally, the deployed system demonstrates feasibility in typical indoor space room dimensions.