Fuzzy Logic Based Dynamic Handover Scheme for Indoor Li-Fi and RF Hybrid Network

Light Fidelity (LiFi) is a recently proposed technology that combines illumination and high speed wireless communication using light emitting diodes (LEDs). Since the used electromagnetic spectrum does not overlap with the radio frequency (RF) spectrum, a small cell LiFi attocell network can be added to the conventional RF network as an additional networking layer in order to mitigate the data traffic bottlenecks in high density environments. In such a hybrid LiFi/RF network where the LiFi attocell covers a few square meters, user movement may prompt frequent handovers, and the handover overhead would degrade the system throughput. The goal is to reduce the handover overhead by appropriately assigning users to either the RF or the LiFi access point (AP). In this study, a fuzzy logic (FL) based dynamic handover scheme is proposed. This FL scheme uses not only the channel state information (CSI), but also the user speed and desired data rate to determine whether a handover needs to be prompted. Simulation shows that the proposed scheme outperforms the conventional handover algorithms, and the performance improvement is approximately 40% in terms of both data rate and user satisfaction level.