Improved bandwidth performance of hybrid optical wireless communication for an indoor IoT environment

Abstract

In this paper, we propose the hybrid optical wireless communication system using a single light-emitting diode (LED) as a transmitter (Tx) as well as a photodiode and image sensor-based receivers (Rxs) for an indoor IoT environment. The proposed system utilizing a single LED offers simultaneously high- and low-speed transmission capabilities using visible light communication (VLC) and optical camera communication (OCC) links, respectively. The proposed scheme is intended to provide a versatile IoT environment by giving users the choice to switch between links based on device availability. By means of experimental implementation, we show that using a chip LED modulated with bipolar on-off keying modulation format and biased voltage levels improves signal transmission on both VLC and OCC links and thus the throughput of the system. Furthermore, we propose amplitude overlap A(OL) in the modulation format to improve the data throughput of VLC link. The results depict that error-free transmission is achieved for the VLC link at a data rate of up to 100 Mb/s which is double the 3-dB bandwidth of LED at A(OL) values of 0.3 and 0.5, and for the OCC link at a data rate of up to 2 kb/s at A(OL) values of 0 and 0.3.