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.

中文翻译：

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混合 LiFi 和 WiFi 网络的负载平衡：解决用户移动性和光路阻塞问题

结合光保真 (LiFi) 的高速数据传输和无线保真 (WiFi) 无处不在的覆盖范围，最近提出了混合 LiFi 和 WiFi 网络 (HLWNets)，以提高室内无线通信的系统容量。同时，由于 LiFi 和 WiFi 的覆盖区域完全重叠，负载平衡成为一个具有挑战性的问题。用户移动性和光路阻塞进一步使负载平衡过程复杂化，因为在具有超小型蜂窝的移动环境中决定是水平切换还是垂直切换并非易事。在大多数传统方法中，这些问题是单独管理的，这可能会导致频繁的切换并影响吞吐量。一些研究共同解决了这些问题，以在每个时刻选择接入点，但需要过多的计算复杂性。在本文中，制定了一个联合优化问题来确定一段时间内每个用户的网络级选择。还提出了一种基于模糊逻辑的新算法，以降低求解优化问题所需的计算复杂度。结果表明，与传统方法相比，所提出的方法可以将系统吞吐量提高高达 68%，同时实现非常低的计算复杂度。