Theoretical Accuracy Analysis of Indoor Visible Light Communication Positioning System Based on Received Signal Strength Indicator

This paper analyzes an indoor positioning system using white lighting LEDs. The performance of the positioning system is determined by the layout of LEDs, the receiver circuit, incidence angle of light, LED light source, and the photodiode. The Cramer-Rao bound as the theoretical accuracy limitation of received signal strength indicator algorithm is derived. The influences to positioning accuracy of multipath reflections and unparallel optical axis of LEDs and receivers are analyzed in certain scenarios. It is concluded that if the diffuse channel gain is measured previously in a certain environment and the modulation speed is far less than the channel cutoff frequency, the theoretical accuracy limit is not affected by multipath link. Multiple noises of system are analyzed in detail. The influence to positioning accuracy of indoor uniform illumination is also discussed. The result proves that the theoretical estimated accuracy of triangular LEDs array is higher than square LEDs array. With typical parameter values, the simulated theoretical accuracy of system is up to the level of centimeter.