Visible Light Communication Based Indoor Localization PDF Download

With the rapid development of Global Positioning Systems (GPS), the field location based services (LBS) is getting more and more attention. For indoor environments, LBS has a wide application for both civil and industrial areas. To make indoor LBS available, positioning technology has become a popular research topic in recent years. This dissertation investigates several indoor positioning topics based on visible light communication (VLC).First, it demonstrates the motivation to realize indoor LBS. Second, several positioning approaches are introduced to provide the location information. Positioning systems such as wireless local access network (WLAN), Zigbee, Bluetooth and radio frequency identification (RFID) are addressed. Third, fundamentals of VLC technology is detailed by explaining the light emitting diode (LED) as the transmitter, the photodiode (PD) as the receiver and the channel direct current (DC) gain considering the line-of-sight (LOS) condition. Visible light positioning systems are realized with lateration techniques based on received signal strength (RSS) information detected by PD. Two channel access methods are detailed and their advantages and disadvantages are analyzed. When height information of the receiver is unknown, three dimensional positioning is realized with an iterative algorithm based on the pre-estimation of the vertical coordinates. In order to further improve the positioning accuracy and alleviate the effect of large deviations, Kalman filter, particle filter as well as Gaussian mixture sigma point particle filter (GM-SPPF) are applied for both 2-D and 3-D scenarios. Considering the vertical accuracy cannot be improved largely from the filtering techniques, a nonlinear estimation algorithm is proposed based on a trust region algorithm.Multipath propagation is one of the most important factors that affects the performance of indoor positioning systems. In this dissertation, impulse response with multipath reflections are analyzed with the combined deterministic and modified Monte Carlo (CDMMC) algorithm. The received optical power from different LED bulbs and the positioning accuracy for the entire room is detailed. Orthogonal frequency division multiplexing (OFDM) is also proposed in the positioning system, considering OFDM performs well when multipath reflections exist. Positioning performance is largely improved with OFDM compared to On-off-keying (OOK) modulation. Finally, conclusions and future works are described in Chapter 9.