476 research outputs found
Design of Ad Hoc Wireless Mesh Networks Formed by Unmanned Aerial Vehicles with Advanced Mechanical Automation
Ad hoc wireless mesh networks formed by unmanned aerial vehicles (UAVs)
equipped with wireless transceivers (access points (APs)) are increasingly
being touted as being able to provide a flexible "on-the-fly" communications
infrastructure that can collect and transmit sensor data from sensors in
remote, wilderness, or disaster-hit areas. Recent advances in the mechanical
automation of UAVs have resulted in separable APs and replaceable batteries
that can be carried by UAVs and placed at arbitrary locations in the field.
These advanced mechanized UAV mesh networks pose interesting questions in terms
of the design of the network architecture and the optimal UAV scheduling
algorithms. This paper studies a range of network architectures that depend on
the mechanized automation (AP separation and battery replacement) capabilities
of UAVs and proposes heuristic UAV scheduling algorithms for each network
architecture, which are benchmarked against optimal designs.Comment: 12 page
A Survey on Mobile Charging Techniques in Wireless Rechargeable Sensor Networks
The recent breakthrough in wireless power transfer (WPT) technology has empowered wireless rechargeable sensor networks (WRSNs) by facilitating stable and continuous energy supply to sensors through mobile chargers (MCs). A plethora of studies have been carried out over the last decade in this regard. However, no comprehensive survey exists to compile the state-of-the-art literature and provide insight into future research directions. To fill this gap, we put forward a detailed survey on mobile charging techniques (MCTs) in WRSNs. In particular, we first describe the network model, various WPT techniques with empirical models, system design issues and performance metrics concerning the MCTs. Next, we introduce an exhaustive taxonomy of the MCTs based on various design attributes and then review the literature by categorizing it into periodic and on-demand charging techniques. In addition, we compare the state-of-the-art MCTs in terms of objectives, constraints, solution approaches, charging options, design issues, performance metrics, evaluation methods, and limitations. Finally, we highlight some potential directions for future research
Resource Allocation in Wireless Networks with RF Energy Harvesting and Transfer
Radio frequency (RF) energy harvesting and transfer techniques have recently
become alternative methods to power the next generation of wireless networks.
As this emerging technology enables proactive replenishment of wireless
devices, it is advantageous in supporting applications with quality-of-service
(QoS) requirement. This article focuses on the resource allocation issues in
wireless networks with RF energy harvesting capability, referred to as RF
energy harvesting networks (RF-EHNs). First, we present an overview of the
RF-EHNs, followed by a review of a variety of issues regarding resource
allocation. Then, we present a case study of designing in the receiver
operation policy, which is of paramount importance in the RF-EHNs. We focus on
QoS support and service differentiation, which have not been addressed by
previous literatures. Furthermore, we outline some open research directions.Comment: To appear in IEEE Networ
Improving sensor network performance with wireless energy transfer
Through recent technology advances in the field of wireless energy transmission Wireless Rechargeable Sensor Networks have emerged. In this new paradigm for wireless sensor networks a mobile entity called mobile charger (MC) traverses the network and replenishes the dissipated energy of sensors. In this work we first provide a formal definition of the charging dispatch decision problem and prove its computational hardness. We then investigate how to optimise the trade-offs of several critical aspects of the charging process such as: a) the trajectory of the charger; b) the different charging policies; c) the impact of the ratio of the energy the Mobile Charger may deliver to the sensors over the total available energy in the network. In the light of these optimisations, we then study the impact of the charging process to the network lifetime for three characteristic underlying routing protocols; a Greedy protocol, a clustering protocol and an energy balancing protocol. Finally, we propose a mobile charging protocol that locally adapts the circular trajectory of the MC to the energy dissipation rate of each sub-region of the network. We compare this protocol against several MC trajectories for all three routing families by a detailed experimental evaluation. The derived findings demonstrate significant performance gains, both with respect to the no charger case as well as the different charging alternatives; in particular, the performance improvements include the network lifetime, as well as connectivity, coverage and energy balance properties
Safe and Secure Wireless Power Transfer Networks: Challenges and Opportunities in RF-Based Systems
RF-based wireless power transfer networks (WPTNs) are deployed to transfer
power to embedded devices over the air via RF waves. Up until now, a
considerable amount of effort has been devoted by researchers to design WPTNs
that maximize several objectives such as harvested power, energy outage and
charging delay. However, inherent security and safety issues are generally
overlooked and these need to be solved if WPTNs are to be become widespread.
This article focuses on safety and security problems related WPTNs and
highlight their cruciality in terms of efficient and dependable operation of
RF-based WPTNs. We provide a overview of new research opportunities in this
emerging domain.Comment: Removed some references, added new references, corrected typos,
revised some sections (mostly I-B and III-C
Extending Wireless Rechargeable Sensor Network Life without Full Knowledge
When extending the life of Wireless Rechargeable Sensor Networks (WRSN), one challenge is charging networks as they grow larger. Overcoming this limitation will render a WRSN more practical and highly adaptable to growth in the real world. Most charging algorithms require a priori full knowledge of sensor nodes’ power levels in order to determine the nodes that require charging. In this work, we present a probabilistic algorithm that extends the life of scalable WRSN without a priori power knowledge and without full network exploration. We develop a probability bound on the power level of the sensor nodes and utilize this bound to make decisions while exploring a WRSN.We verify the algorithm by simulating a wireless power transfer unmanned aerial vehicle, and charging a WRSN to extend its life. Our results show that, without knowledge, our proposed algorithm extends the life of a WRSN on average 90% of what an optimal full knowledge algorithm can achieve. This means that the charging robot does not need to explore the whole network, which enables the scaling of WRSN. We analyze the impact of network parameters on our algorithm and show that it is insensitive to a large range of parameter values
Probabilistic On-Demand Charging Scheduling for ISAC-Assisted WRSNs with Multiple Mobile Charging Vehicles
The internet of things (IoT) based wireless sensor networks (WSNs) face an
energy shortage challenge that could be overcome by the novel wireless power
transfer (WPT) technology. The combination of WSNs and WPT is known as wireless
rechargeable sensor networks (WRSNs), with the charging efficiency and charging
scheduling being the primary concerns. Therefore, this paper proposes a
probabilistic on-demand charging scheduling for integrated sensing and
communication (ISAC)-assisted WRSNs with multiple mobile charging vehicles
(MCVs) that addresses three parts. First, it considers the four attributes with
their probability distributions to balance the charging load on each MCV. The
distributions are residual energy of charging node, distance from MCV to
charging node, degree of charging node, and charging node betweenness
centrality. Second, it considers the efficient charging factor strategy to
partially charge network nodes. Finally, it employs the ISAC concept to
efficiently utilize the wireless resources to reduce the traveling cost of each
MCV and to avoid the charging conflicts between them. The simulation results
show that the proposed protocol outperforms cutting-edge protocols in terms of
energy usage efficiency, charging delay, survival rate, and travel distance.Comment: Accepted for publication at the IEEE Global Communications Conference
(GLOBECOM) 202
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