Light fidelity (LiFi) is a recently proposed wireless technology that operates in a way similar to wireless fidelity (WiFi) but uses light as a signal bearer. Combining the high-speed data transmission of LiFi and the ubiquitous coverage of WiFi, hybrid LiFi and WiFi networks (HLWNets) are able to improve the system capacity of indoor wireless communications. Meanwhile, the process of access point (AP) selection becomes challenging, since the coverage areas of different networks completely overlap each other. Relying on instantaneous channel information, the conventional load balancing method assigns each user to a specific AP, providing the optimal solution for a given time instant. However, this method might cause frequent handovers for mobile users and compromise their throughputs. In this paper, mobility-aware load balancing (MALB) methods are proposed for HLWNets in both single transmission (ST) and multiple transmission (MT) modes. In the ST mode, each user is served by only one AP, chosen from either LiFi or WiFi. In this mode, the proposed method assigns each user to a certain type of network over a period of time, to suppress vertical handovers. In the MT mode, each user is simultaneously served by LiFi and WiFi, and no vertical handover occurs. A joint optimization problem is formulated to balance traffic loads between LiFi and WiFi in this mode. Results show that against the conventional load balancing method, MALB-ST and MALB-MT can improve system throughput by up to 46% and 76%, respectively, with significantly reduced computational complexity. (C) 2019 Optical Society of America
