An Orientation-based Random Waypoint Model for User Mobility in Wireless Networks

In the context of optical wireless communications (as well as millimeter wave and terahertz systems), it is important to consider the random orientation of the user equipment (UE). At such small wavelengths, the UE's random orientation affects the angle of arrival or incidence angle that leads to a change in channel gain as well as the received signal-to-noise ratio (SNR). Furthermore, it can result in frequent handover that may affect user's quality of experience. Hence, it is required to consider the random orientation of the UE in our analysis to obtain more realistic results. Therefore, a framework that combines the conventional mobility models with the random orientation model is required. In this study, we propose an extended orientation-based random waypoint mobility model, in which the random orientation of the UE is considered during both walking and pause time. The parameters of the model are set based on the experimental measurements of device orientation. The application of this model to an indoor light-fidelity (LiFi) network is studied as a use case by analyzing the handover rate.