Browsing by Author "Mahmoodi, Khadijeh Ali"

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Energy aware trajectory optimization of solar powered AUVs for optical underwater sensor networks
(IEEE, 2022-12) Mahmoodi, Khadijeh Ali; Uysal, Murat; Electrical & Electronics Engineering; UYSAL, Murat; Mahmoodi, Khadijeh Ali
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.
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Operation altitude optimization of solar-powered rotary-wing UAVs for FSO backhauling
(IEEE, 2023) Mahmoodi, Khadijeh Ali; Elamassie, Mohammed; Uysal, Murat; Electrical & Electronics Engineering; ELAMASSIE, Mohammed; UYSAL, Murat; Mahmoodi, Khadijeh Ali
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 quantity 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.