Hybrid Optical Wireless Communication for Versatile IoT Applications: Data Rate Improvement and Analysis.

This paper outlines the concept of a multilevel bipolar on-off keying hybrid optical wireless communication (OWC) system using a single light-emitting diode (LED) as a transmitter as well as photodiode and camera-based receivers for versatile indoor Internet of Things applications. The proposed system offers simultaneous high- and low-speed transmission capabilities using visible light communication (VLC) and optical camera communication (OCC) links, respectively. By means of experimental implementation, we show that the hybrid OWC system employing a chip LED modulated with a multilevel signal improves the data rate $R_{b}$ as well as the bit error rate and reception success rate of VLC and OCC links, respectively, by doubling the bandwidth. We show that the proposed scheme can provide an independent link performance, irrespective of significant differences between the operating $R_{b}$ of VLC and OCC over a range of transmission spans $L$ . We demonstrate that the throughput of the VLC link is improved by up to $\sim $ 100 Mb/s, which corresponds to twice the LED bandwidth, using direct modulation, different amplitude levels, and optimizing the received optical power of the hybrid OWC link. Error-free data transmission for the OCC link is achieved for all values of $R_{b}$ , amplitude overlap of 0 and 0.3, and a range of $L$ .