2,015 research outputs found
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
Max-min Fair Beamforming for SWIPT Systems with Non-linear EH Model
We study the beamforming design for multiuser systems with simultaneous
wireless information and power transfer (SWIPT). Employing a practical
non-linear energy harvesting (EH) model, the design is formulated as a
non-convex optimization problem for the maximization of the minimum harvested
power across several energy harvesting receivers. The proposed problem
formulation takes into account imperfect channel state information (CSI) and a
minimum required signal-to-interference-plus-noise ratio (SINR). The globally
optimal solution of the design problem is obtained via the semidefinite
programming (SDP) relaxation approach. Interestingly, we can show that at most
one dedicated energy beam is needed to achieve optimality. Numerical results
demonstrate that with the proposed design a significant performance gain and
improved fairness can be provided to the users compared to two baseline
schemes.Comment: Invited paper, IEEE VTC 2017, Fall, Toronto, Canad
Radiation Aware Mobility Paths in Wirelessly Powered Communication Networks
Wireless power transfer (WPT) is an emerging technology that is used in ad hoc networks of battery-powered devices, to deliver energy and keep the network functional. Existing state-of-the-art studies have mainly focused on applying this technology, but the potential risk of electromagnetic radiation (EMR) exposure is really overlooked by them. This still holds for the general case of the RF Wireless Communication networks. Hence, we consider The Minimum Radiation Path Problem of finding the lowest radiation trajectory of an agent moving from a source to a destination point in a network plane. Different from previous works, we attempt to study (for the first time in the state-of-the-art) path radiation under a more realistic WPT model than the usual one-dimensional models, that have been used in the past and cannot capture interesting superadditive and cancellation effects between distinct electromagnetic sources. In the light of the above, we design and evaluate both an algorithm and a heuristic that achieve different trade-offs between radiation and trajectory length of a moving agent.
Document type: Conference objec
Adaptive wireless power transfer in mobile ad hoc networks
We investigate the interesting impact of mobility on the problem of efficient wireless power transfer in ad hoc networks. We consider a set of mobile agents (consuming energy to perform certain sensing and communication tasks), and a single static charger (with finite energy) which can recharge the agents when they get in its range. In particular, we focus on the problem of efficiently computing the appropriate range of the charger with the goal of prolonging the network lifetime. We first demonstrate (under the realistic assumption of fixed energy supplies) the limitations of any fixed charging range and, therefore, the need for (and power of) a dynamic selection of the charging range, by adapting to the behavior of the mobile agents which is revealed in an online manner. We investigate the complexity of optimizing the selection of such an adaptive charging range, by showing that two simplified offline optimization problems (closely related to the online one) are NP-hard. To effectively address the involved performance trade-offs, we finally present a variety of adaptive heuristics, assuming different levels of agent information regarding their mobility and energy
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