Dynamic Load Balancing With Handover in Hybrid Li-Fi and Wi-Fi Networks
Dynamic Load Balancing With Handover in Hybrid Li-Fi and Wi-Fi Networks
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DOI：
10.1109/jlt.2015.2480969
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发表时间：
2015-11
影响因子：
4.7
通讯作者：
Yunlu Wang;H. Haas
中科院分区：
文献类型：
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作者：
Yunlu Wang;H. Haas
本文考虑了一种结合光保真（Li-Fi）和射频（RF）无线保真（Wi-Fi）网络的混合网络。另外一层非常小的Li-Fi attocell利用可见光谱，在室内环境中显著提高无线数据吞吐量，同时提供室内照明。重要的是，Li-Fi和Wi-Fi之间没有干扰。Li-Fi attocell覆盖的区域明显小于Wi-Fi接入点（AP）。这意味着即使在适度的用户移动的情况下，也可能发生Li-Fi attocell之间的大量切换，并且这会损害系统吞吐量。动态负载均衡（LB）可以缓解这个问题，使得准静态用户由Li-Fi attocell服务，而移动用户由Wi-Fi AP服务。然而，由于用户移动，可能发生阻止切换的本地过载情况，导致较低的吞吐量。本研究通过考虑用户移动性和切换信令开销来研究混合Li-Fi/Wi-Fi网络中的LB。此外，提出了一种动态LB方案，其中效用函数考虑系统吞吐量和公平性。为了更好地理解切换对LB的影响，不同的AP的服务区域进行了研究，并通过采用所提出的LB方案的每个AP的吞吐量进行了分析。
In this paper, a hybrid network combining light fidelity (Li-Fi) with a radio frequency (RF) wireless fidelity (Wi-Fi) network is considered. An additional tier of very small Li-Fi attocells which utilize the visible light spectrum, offers a significant increase in the wireless data throughput in an indoor environment, while at the same time providing room illumination. Importantly, there is no interference between Li-Fi and Wi-Fi. A Li-Fi attocell covers a significantly smaller area than a Wi-Fi access point (AP). This means that even with a moderate user movement a large number of handover between Li-Fi attocells can occur, and this compromises the system throughput. Dynamic load balancing (LB) can mitigate this issue so that the quasi-static users are served by Li-Fi attocells, while moving users are served by a Wi-Fi AP. However, due to the user movement, local overload situations may occur which prevent handover, leading to a lower throughput. This research studies LB in a hybrid Li-Fi/Wi-Fi network by taking into account user mobility and handover signalling overheads. Furthermore, a dynamic LB scheme is proposed, where the utility function considers system throughput and fairness. In order to better understand the handover effect on the LB, the service areas of different APs are studied, and the throughput of each AP by employing the proposed LB scheme is analyzed.