A fingerprinting-based indoor localization system using intensity modulation of light emitting diodes

In this article, we propose a two-dimensional indoor localization system using fingerprinting of received optical signals emitted from light emitting diodes (LEDs).The transmitters and receiver are designed and constructed to use visible light as the signal for localization. At the transmitter side, the input voltage/current is modulated with continuous waves before being sent to the LEDs, where each transmitter is assigned with a different frequency. At the receiver side, the power spectral density of the received signal is calculated and the location is estimated as one of the fingerprint locations using a novel but yet simple algorithm. Both the simulation and experiment have been conducted to evaluate the accuracy of the system in a controlled environment. We demonstrate that the system has the potential to estimate locations in the level of centimeters. (C) 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:12181227, 2012