Abstract
The Internet of Things (IoT) is a transformative technology marking the
beginning of a new era where physical and digital worlds are integrated
by connecting a plethora of uniquely identifiable smart objects.
Although the Internet of terrestrial things (IoTT) has been at the
center of our IoT perception, it has been recently extended to different
environments, such as the Internet of underWater things (IoWT), the
Internet of Biomedical things (IoBT), and Internet of underGround things
(IoGT). Even though radio frequency (RF) based wireless networks are
regarded as the default means of connectivity, they are not always the
best option due to the limited spectrum, interference limitations caused
by the ever-increasing number of devices, and severe propagation loss in
transmission mediums other than air. As a remedy, optical wireless
communication (OWC) technologies can complement, replace, or co-exist
with audio and radio wave-based wireless systems to improve overall
network performance. To this aim, this paper reveals the full potential
of OWC-based IoT networks by providing a top-down survey of four main
IoT domains: IoTT, IoBT, and IoGT. Each domain is covered by a dedicated
and self-contained section that starts with a comparative analysis,
explains how OWC can be hybridized with existing wireless technologies,
points out potential OWC applications fitting best the related IoT
domain, and discusses open communication and networking research
problems. More importantly, instead of presenting a visionary OWC-IoT
framework, the survey discloses that OWC-IoT has become a reality by
emphasizing ongoing proof-of-concept prototyping efforts and available
commercial off-the-shelf (COTS) OWC-IoT products.