Spatial Interference Detection for Mobile Visible Light Communication

With the explosion of the Internet of Things (IoT), the number of devices to identify grew up exponentially in recent years and solutions such as visual markers or radio technologies are starting to show their limits. Visible light markers have been proposed to overcome these limitations. However, visible light communication (VLC) is very sensitive to interferences. As such, if two light markers are overlapping, the corresponding signals cannot be recovered. In smart homes, this situation is likely to occur as devices can be placed in very close proximity. In this paper, we design a protocol based on orthogonal codes to detect and isolate adjacent light markers, and individually identify several contiguous objects. We implement the algorithms within an Android application and evaluate their effect both analytically and experimentally. We demonstrate the robustness of our protocol in different conditions, both at the transmitter and the receiver side. Light markers are correctly recovered with low error rates (under 5%), at a pace of 5 frames per second, enough for object identification in most IoT scenarios.