Load Balancing for Hybrid LiFi and WiFi Networks: To Tackle User Mobility and Light-Path Blockage

Abstract

Combining the high-speed data transmission of light fidelity (LiFi) and the ubiquitous coverage of wireless fidelity (WiFi), hybrid LiFi and WiFi networks (HLWNets) are recently proposed to improve the system capacity of indoor wireless communications. Meanwhile, load balancing becomes a challenging issue due to a complete overlap between the coverage areas of LiFi and WiFi. User mobility and light-path blockages further complicate the process of load balancing, since the decision for a horizontal or a vertical handover in a mobile environment with ultra-small cells is non-trivial. These issues are managed separately in most conventional methods, which might cause frequent handovers and compromise throughput. A few studies address these issues jointly for selecting access points at each time instant but require excessive computational complexity. In this paper, a joint optimisation problem is formulated to determine a network-level selection for each user over a period of time. A novel algorithm based on fuzzy logic is also proposed to reduce the computational complexity that is required to solve the optimisation problem. Results show that compared to the conventional method, the proposed approach can improve system throughput by up to 68%, while achieving very low computational complexity. Index Terms-Light fidelity (LiFi), hybrid network, load balancing, user mobility, light-path blockage

Hybrid LiFi and WiFi Networks: A Survey

“…This blockage model can be combined with the orientation-aware RWP model, establishing a joint model to comprehensively analyze the impact of user behavior. A statistical model of blockage is also available [62]. This model characterizes blockage with occurrence rate and occupation rate, which measure how often the blockage occurs and how long the blockage lasts, respectively.…”

“…Wang et al [101] developed a fuzzy logic system to balance the traffic loads between LiFi and WiFi, with multiple input parameters including SINR, the user's speed and data rate requirements. Adding light-path blockage as an extra input, another fuzzy logic-based LB approach was proposed in [62] to handle the situation of unbalanced traffic loads caused by blockage. While fuzzy logic can be readily implemented, the logic rules are pre-defined and lack flexibility.…”

An Industrial View on LiFi Challenges and Future

“…The cohabitation of LiFi with other RF technologies within heterogeneous networks is another major issue that will arise as LiFi deployment expands as part of the 6G framework. These heterogeneous networks raise the question of vertical handover from one technology to another, on which some work has already been done [13]. The LiFi link can indeed be cut if the photoreceiver is obstructed.…”

“…Although the term LiFi was forged in 2011, the idea of creating wireless networks through light can be traced back to at least 1979 [6] and has then seen a lot of works based on IR in the 1990s [7]. For several years now, LiFi has been attracting increasing attention from the academic world, which has been interested in topics as varied as the performance improvement with off-the-shelf or custom components [8]- [11], the study of the impact of user mobility [12], [13], but also its application to various use cases such as robotics [14].…”

A Novel Machine Learning-Based Handover Scheme for Hybrid LiFi and WiFi Networks

“…Moreover, [4]- [6] fail to accommodate the impact of user mobility. In [7], the concept of mobility-aware load balancing was introduced. This method takes the handover cost into account when maximising network throughput, while still needing considerable computational complexity.…”