Impact of terminal orientation on performance in LiFi systems

Visible light communication and its use in wireless networks, which is referred to as light fidelity (LiFi), can potentially provide ubiquitous indoor broadband connections. Most of the existing studies on LiFi consider a device that always faces upward, disregarding the importance of the orientation of the device. This paper presents experimental results on the randomly-oriented devices and a statistical model of the LiFi channel considering the random orientation. The distribution of the cosine of the incidence angle is shown to have a Laplacian form. This distribution is then applied to study the signal-to-noise ratio of the randomly-oriented and the upward-facing devices. Finally, we show that neglecting the random orientation can lead to inaccurate conclusions. Hence, it is important to take the random orientation into account in future LiFi network analyses.