RSS-based visible light positioning based on channel state information

As a result of the influence of indoor multipath effects, visible light positioning (VLP) technology based on the received signal strength (RSS) has difficulty providing stable and highly accurate position estimation. In order to cope with this challenge, a trilateration-based positioning method using channel state information (CSI) is proposed. Two algorithms that can estimate the number of channel paths are studied, which are the prerequisites for the obtaining of an accurate ratio of received power of the line-of-sight (LOS) path to total received power. Unlike traditional trilateration positioning methods where total received power is used, the proposed method introduces CSI as a means of estimating the received power of the LOS path, which it uses for ranging. By reducing interference from the reflected paths in the received power, the proposed method has high-precision and high-reliability positioning capabilities. The positioning performance of the proposed method in an indoor environment with four LED bulbs and a single photodetector (PD) is evaluated through simulation. The simulation results demonstrate that the proposed method provides an average accuracy of 6.1 cm and a maximum positioning error of 17.7 cm in a cubic space with a size of 4 m×4 m×3 m. Compared to the existing least-squares (LS) method that uses total received power, the new method achieves approximately 83% improvement in the mean error of positioning and 81% in root mean square error (RMSE).