AquaE-lite Hybrid-Solar-Cell Receiver-Modality for Energy-Autonomous Terrestrial and Underwater Internet-of-Things

Abstract

Our goal is to develop an energy-autonomous solar cell receiver that can be integrated with a variety of smart devices to implement the Internet of Things in next-generation applications. This paper details efforts to develop such a prototype, called AquaE-lite. Owing to the capability of detecting low-intensity optical signals, 20-m and 30-m long-distance lighting and optical wireless communication with data rates of 1.6 Mbit/s and 1.2 Mbit/s have been achieved on a laboratory testbed, respectively. Moreover, field trials on an outdoor solar cell testbed and in the turbid water of a harbor by the Red Sea have been conducted. Under bright sunlight, energy autonomy and 1.2-Mbit/s optical wireless communication over a transmission distance of 15 m have been implemented, which demonstrated that AquaElite with an elaborate receiver circuit has excellent performance in energy harvesting and resistance to background noise. In a more challenging underwater environment, 1.2-Mbit/s signals were successfully received over a transmission distance of 2 m. It indicates that energy-autonomous AquaE-lite with large detection area has promising prospects in future underwater mobile sensor networks to significantly relieve the requirement of pointing, acquisition and tracking while resolving the energy issues.

The Impact of Vertical Salinity Gradient on Non-Line-of-Sight Underwater Optical Wireless Communication

“…Several novel solutions can be adopted to build robust UWOC links that are resilient to underwater turbulence, such as employing optical receivers with large detection areas [29]. In addition, the implantation of non-line-of-sight (NLOS) configurations combats channel impairments and eases the requirement of strict positioning, acquisition, and tracking while providing high-speed connectivity [30], and resilience to turbulence [20].…”

Toward Automatic Subsea Operations Using Real-Time Underwater Optical Wireless Sensor Networks

“…The water type at the harbor was optically complex waters like coastal area where it is dominated by suspended particles such as sediments as shown in Fig. 10(b) and 10(c) [13]. In the field trial, Sensor Node 2 was placed 0.6 m away from the optical hub as shown in Fig.…”

Current Trend in Optical Internet of Underwater Things

“…In [14], to achieve an integrated system with efficient underwater energy acquisition and weak-light signal detection, a hybrid solar cell receiver, named AquaE-lite II, as shown in Fig. 9(b), was developed.…”