A Distributed Passive Front End Based Visible Light Communication System for Optical IoT

This paper proposes a novel bidirectional indoor visible light communication (VLC) system that uses a pair of plastic optical fibers (POF), a scintillation fiber (SF) and a side-emitting fiber (SEF), to create a distributed passive front end. This proposed system offers several advantages, including a simple structure, low cost, flexible construction and easy maintenance. In this system, SF is used for uplink and SEF is used for downlink. To investigate the SF and SEF based system's performance, models for estimating the frequency response and power attenuation for the two fibers have been derived and experimentally validated. Meanwhile, the directivity of the two fibers has been tested. At a transmitted power of 2 mW, an uplink data rate of 284 Mbps and a downlink data rate of 212 Mbps have been demonstrated in the dark for the first time by this all passive distributed front end based VLC system. Combining the validated fiber model with the typical VLC model, the coverage performance of the proposed VLC system has been estimated. Results presented in this paper suggest that the full coverage of 25 m$^{2}$ can be achieved. The method of how to design and select the best SF and SEF to mitigate the impact of ambient light is then discussed.