Miller-Coded Asynchronous Visible Light Positioning System for Smart Phones

Indoor location based service (LBS) has become one of the key enablers for the mobile internet era. The challenging indoor localisation problem may be solved by the emerging visible light positioning (VLP) techniques which exploit light-emitting diode (LED) to transmit beacon signals. In this paper, we propose a general VLP system which invokes an imaging receiver, an off-the-shelf LED lamp and a commercial user equipment (UE) employing a rolling shutter aided complementary metal-oxide semiconductor (CMOS) based image sensor (CIS). Particularly, we design an asynchronous framework based on Miller coding, which efficiently solves the synchronisation problem. Furthermore, we provide a detailed analysis on a discrete Fourier transform (DFT) aided LED flicker frequency detection algorithm. Extensive measurement and simulation results are also offered.