Beam Control for Indoor FSO and Dynamic Dual-Use VLC Lighting Systems

Practical VLC (Visible Light Communication) systems are expected to leverage the lighting infrastructure in order to deliver data to devices in a lighting field. These devices can be static or quasi-static (e.g., laptops or IoT devices); however, it is becoming clear that the preponderance of wireless data consumption is dominated by handheld mobile devices which will exhibit varying physical orientations and 3D dynamics. Because free-space optical and visible light communications are primarily line of sight, transmitter radiation patterns and receiver field of view are very important for predicting the data performance. Given dynamic emission characteristics, there is an opportunity to adapt to the receiver. The caveat of dynamic VLC systems is that the quality and distribution of the resulting illumination must be considered as part of the dual goal of providing high quality lighting. In this paper we investigate the impact of device orientation and mobility on static and then dynamic lighting emission under a multi-cell lighting model. From a source standpoint we consider the performance of beam control through angular control and beam focus for one or more sources in a lighting array. Analysis and simulation demonstrate that dynamic beam and luminaire control can increase the AP coverage range by 12.8X under a 1.67 m ceiling height. Furthermore, the use of multiple sources tracking device orientation and position can mitigate off-angle performance degradation by increasing redundancy in the number of available connections. Our proposed techniques, when applied in concert, successfully mitigate common concerns about the viability of VLC and indoor FSO (Free Space Optical Communication) methods related to signal occlusion and device dynamics.