Autonomous underwater vehicles (AUVs) are instrumental for data offloading in underwater sensor networks (USNs). With high data rate capacity at transmission ranges in the order of several tens of meters, visible light communication (VLC) is well-positioned to serve as a wireless link between the AUV and sensor nodes. In this paper, we consider a USN network where an AUV is used for data retrieval from the sensors through VLC link. We formulate the design of optimal AUV trajectory as an optimization problem to minimize the AUV energy consumption under data rate constraints imposed by the VLC link and in the presence of ocean currents. Our numerical results demonstrate that our proposed trajectory is reactive to ocean currents and brings significant reductions in energy consumption and mission time of the AUVs, in particular for USN scenarios with a large number of sensor nodes.
Optical camera communications (OCCs) technology, which utilizes lighting infrastructure for both illumination and data transmission and camera as the receiver, recently has drawn a lot of attention and luckily it can be used for indoor positioning as well. We consider an indoor environment with a number of light emitting diodes (LEDs) lighting access points for positioning and estimate the location using the view angles between LEDs' images mapped onto the image plane. The impact of the number of LEDs, which are varied from 3 to 9, on the positioning accuracy is investigated theoretically and validated experimentally. We show that increasing the number of LEDs has a significant effect on the performance of the OCC-based indoor positioning systems (IPSs).
Visible light communication (VLC) provides an alternative underwater wireless connectivity solution with its low latency and high data rates albeit at relatively shorter distances in the order of tens of meters. In the context of underwater sensor networks (USNs), VLC is particularly suitable to establish connectivity between "data mule" autonomous underwater vehicles (AUVs) and sensor nodes since communications is enabled only when the sensor node and mule AUV are in close proximity. In this paper, we consider a USN scenario where a solar-powered AUV gathers data from the sensor nodes using VLC signaling. We formulate a three-dimensional trajectory optimization for solar-powered AUVs with the goal of maximizing the harvested energy under constraints imposed by the data transmission. The optimization constraints include the minimum required data transfer rate, therefore a corresponding transmission distance, between the sensors and the AUV. We formulate the problem as a bilevel optimization problem. The lower-level objective function is in the form of traveling salesman problem which determines the optimum sequence order of the sensor nodes to be visited while the upper-level objective function is the optimization of the trajectory between each pair of adjacent nodes for the given order of node visits. Our numerical results demonstrate that the proposed trajectory significantly prolongs the mission time and autonomous operation of the AUV without the need to return to home base. Furthermore, since the proposed trajectory optimization is reactive to ocean currents, it brings reductions in the energy consumption of the AUVs.
Free space optical communication (FSO) has emerged as an alternative backhauling technology. It provides a line-of-sight (LOS) link with a capacity comparable to fiber optics and much higher than those that can be supported by radio counterparts. Rotary-wing unmanned aerial vehicles (UAVs) equipped with FSO terminals can be positioned as a complementary aerial solution to the terrestrial backhaul links in dense areas with high-peak traffic demands. In this paper, we consider a solar-powered rotary-wing UAV equipped with an FSO terminal that provides backhaul link to a ground base station in an urban area. We first quantify the energy consumption and energy harvesting of a rotary-wing solar-powered UAV. Then, we formulate an optimization problem to determine the optimal operation altitude with the goal of maximizing the net energy of UAV while satisfying the LOS requirements critical for the FSO link. Our results show that the selection of operation altitude is highly dependent on the weight of the UAV as well as the size and efficiency of the solar panel.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.