An in-Depth Survey of Visible Light Communication Based Positioning Systems <s> Mobility <s> This paper describes the prototype of an indoor positioning system (IPS) using LED identification (LED-ID) technology. LED sources transmit unique ID codes which identify users' position. An optical link budget is analyzed and simulated. Our lab prototype can satisfy the required accuracy in some coarse location environments. <s> BIB001 </s> An in-Depth Survey of Visible Light Communication Based Positioning Systems <s> Mobility <s> Indoor physical analytics calls for high-accuracy localization that existing indoor (e.g., WiFi-based) localization systems may not offer. By exploiting the ever increasingly wider adoption of LED lighting, in this paper, we study the problem of using visible LED lights for accurate localization. We identify the key challenges and tackle them through the design of Pharos. In particular, we establish and experimentally verify an optical channel model suitable for localization. We adopt BFSK and channel hopping to achieve reliable location beaconing from multiple, uncoordinated light sources over shared light medium. Preliminary evaluation shows that Pharos achieves the 90th percentile localization accuracy of 0.4m and 0.7m for two typical indoor environments. We believe visible light based localization holds the potential to significantly improve the position accuracy, despite few potential issues to be conquered in real deployment. <s> BIB002
The mobility issue in VLC based positioning was investigated in BIB001 . The simulation results showed that with a 3 W LED base station, an effective positioning radius of 1.3 m is achieved. Then given the bit rate set to 200 kbps, the paper showed that the maximum movement speed of a mobile device is 16.25 km/s. The paper also suggested that a higher bit rate should be applied to achieve steady positioning. In BIB002 , not only the visible light ID but also the location information of LED base stations was transmitted to the receiver. Even though the system used PD, it took 2.1 s to receive all of the necessary signals for positioning. This latency might be unacceptable for applications where the subjects are not quite stationary. 