Robust Visible Light-Based Positioning Under Unknown User Device Orientation Angle

In this paper, the localization issue for LiFi users is studied. Due to the nonlinear dependency of received visible light strength on user geometric location parameters, LiFi localization is a non-convex problem and hence it is of great challenge. In order to reduce the problem complexity, previous solutions usually require a known height of user equipment or a perfect alignment of transceiver orientation angles, which limits the application of such solutions. To solve this problem, we propose a novel algorithm to achieve an easy LiFi localization solution without any requirement on perfect alignment transceiver orientations or prior knowledge of user equipment height. By exploring the inherent convex structure of the problem, the proposed algorithm gives an efficient closed-form update equation for both user location and orientation angle, thus achieving an accurate solution with fast convergence rate. The performance of the proposed localization algorithm is verified by simulations, and it is shown that the proposed algorithm can achieve a huge localization performance gain over existing approaches due to the joint optimization of user location and orientation angle as well as the problem-specific parameter update rule design.