58,512 research outputs found
Wireless Power Charging Control in Multiuser Broadband Networks
Recent advances in wireless power transfer (WPT) technology provide a
cost-effective solution to charge wireless devices remotely without disruption
to the use. In this paper, we propose an efficient wireless charging control
method for exploiting the frequency diversity in multiuser broadband wireless
networks, to reduce energy outage and keep the system operating in an efficient
and sustainable state. In particular, we first analyze the impact of charging
control method to the operating lifetime of a WPT-enabled broadband system.
Based on the analysis, we then propose a multi-criteria charging control policy
that optimizes the transmit power allocation over frequency by jointly
considering the channel state information (CSI) and the battery state
information (BSI) of wireless devices. For practical implementation, the
proposed scheme is realized by a novel limited CSI estimation mechanism
embedded with partial BSI, which significantly reduces the energy cost of CSI
and BSI feedback. Simulation results show that the proposed method could
significantly increase the network lifetime under stringent transmit power
constraint. Reciprocally, it also consumes lower transmit power to achieve
near-perpetual network operation than other single-criterion based charging
control methods.Comment: This paper had been accepted by IEEE ICC 2015, Workshop on Green
Communications and Networks with Energy Harvesting, Smart Grids, and
Renewable Energie
Efficient modeling of the wireless power transfer efficiency for varying positions and orientations between transmitter and receiver
A method that efficiently calculates the Power Transfer Efficiency (PTE) of a Wireless Power Transfer (WPT) system is described in this paper. It allows for arbitrary relative positions and orientations between devices in the system, both in far-field and radiative near-field configurations. The method uses a single simulation or measurement of the radiation patterns of the antennas employed in the WPT system, from which the interaction between devices at any relative position and orientation can be modeled. A spherical harmonics decomposition, together with Wigner-D rotation matrices, is applied to perform efficient translations and rotations of the devices used in the WPT system
Energy-Efficient Resource Allocation in Multiuser OFDM Systems with Wireless Information and Power Transfer
In this paper, we study the resource allocation algorithm design for
multiuser orthogonal frequency division multiplexing (OFDM) downlink systems
with simultaneous wireless information and power transfer. The algorithm design
is formulated as a non-convex optimization problem for maximizing the energy
efficiency of data transmission (bit/Joule delivered to the users). In
particular, the problem formulation takes into account the minimum required
system data rate, heterogeneous minimum required power transfers to the users,
and the circuit power consumption. Subsequently, by exploiting the method of
time-sharing and the properties of nonlinear fractional programming, the
considered non-convex optimization problem is solved using an efficient
iterative resource allocation algorithm. For each iteration, the optimal power
allocation and user selection solution are derived based on Lagrange dual
decomposition. Simulation results illustrate that the proposed iterative
resource allocation algorithm achieves the maximum energy efficiency of the
system and reveal how energy efficiency, system capacity, and wireless power
transfer benefit from the presence of multiple users in the system.Comment: 6 pages. The paper has been accepted for publication at the IEEE
Wireless Communications and Networking Conference (WCNC) 2013, Shanghai,
China, Apr. 201
Modeling and simulation of inductive-based wireless power transmission systems
This chapter studies an inductive-based wireless power transfer system for low-power applications at short distances. The transferring power system has been modeled, simulated and analyzed via finite element method. A wireless power transfer system includes important parts such as coil, core and driver. In this chapter, the important parts of an inductive power transfer system have been analyzed. Receiving and transmitting printed spiral coils are designed in an optimized procedure. The experimental results were in a good agreement with the simulation results. Moreover, based on the performed modulation and simulation the use of the pot core as the receiving core is proposed. It is concluded that this type of core can improve magnetic flux density in the receiving side. Different geometries of coils for transmitting side have been modeled and simulated. An electromagnetic analysis has been done; the experimental result was in a good agreement with the simulation result. This work presents an efficient perspective to coil design
Secrecy Wireless Information and Power Transfer in OFDMA Systems
In this paper, we consider simultaneous wireless information and power
transfer (SWIPT) in orthogonal frequency division multiple access (OFDMA)
systems with the coexistence of information receivers (IRs) and energy
receivers (ERs). The IRs are served with best-effort secrecy data and the ERs
harvest energy with minimum required harvested power. To enhance physical-layer
security and yet satisfy energy harvesting requirements, we introduce a new
frequency-domain artificial noise based approach. We study the optimal resource
allocation for the weighted sum secrecy rate maximization via transmit power
and subcarrier allocation. The considered problem is non-convex, while we
propose an efficient algorithm for solving it based on Lagrange duality method.
Simulation results illustrate the effectiveness of the proposed algorithm as
compared against other heuristic schemes.Comment: To appear in Globecom 201
Joint Secure Beamforming for Cognitive Radio Networks with Untrusted Secondary Users
In this paper, we consider simultaneous wireless information and power
transfer (SWIPT) in orthogonal frequency division multiple access (OFDMA)
systems with the coexistence of information receivers (IRs) and energy
receivers (ERs). The IRs are served with best-effort secrecy data and the ERs
harvest energy with minimum required harvested power. To enhance physical-layer
security and yet satisfy energy harvesting requirements, we introduce a new
frequency-domain artificial noise based approach. We study the optimal resource
allocation for the weighted sum secrecy rate maximization via transmit power
and subcarrier allocation. The considered problem is non-convex, while we
propose an efficient algorithm for solving it based on Lagrange duality method.
Simulation results illustrate the effectiveness of the proposed algorithm as
compared against other heuristic schemes.Comment: To appear in Globecom 201
A Multi-Dimensional Analysis of a Novel Approach for Wireless Stimulation
The elimination of integrated batteries in biomedical implants holds great promise for improving health outcomes in patients with implantable devices. However, despite extensive research in wireless power transfer, achieving efficient power transfer and effective operational range have remained a hindering challenge within anatomical constraints. Objective : We hereby demonstrate an intravascular wireless and batteryless microscale stimulator, designed for (1) low power dissipation via intermittent transmission and (2) reduced fixation mechanical burden via deployment to the anterior cardiac vein (ACV, ∼3.8 mm in diameter). Methods : We introduced a unique coil design circumferentially confined to a 3 mm diameter hollow-cylinder that was driven by a novel transmitter-based control architecture with improved power efficiency. Results : We examined wireless capacity using heterogenous bovine tissue, demonstrating >5 V stimulation threshold with up to 20 mm transmitter-receiver displacement and 20° of misalignment. Feasibility for human use was validated using Finite Element Method (FEM) simulation of the cardiac cycle, guided by pacer phantom-integrated Magnetic Resonance Images (MRI). Conclusion : This system design thus enabled sufficient wireless power transfer in the face of extensive stimulator miniaturization. Significance : Our successful feasibility studies demonstrated the capacity for minimally invasive deployment and low-risk fixation
A Multi-Dimensional Analysis of a Novel Approach for Wireless Stimulation
The elimination of integrated batteries in biomedical implants holds great promise for improving health outcomes in patients with implantable devices. However, despite extensive research in wireless power transfer, achieving efficient power transfer and effective operational range have remained a hindering challenge within anatomical constraints. Objective : We hereby demonstrate an intravascular wireless and batteryless microscale stimulator, designed for (1) low power dissipation via intermittent transmission and (2) reduced fixation mechanical burden via deployment to the anterior cardiac vein (ACV, ∼3.8 mm in diameter). Methods : We introduced a unique coil design circumferentially confined to a 3 mm diameter hollow-cylinder that was driven by a novel transmitter-based control architecture with improved power efficiency. Results : We examined wireless capacity using heterogenous bovine tissue, demonstrating >5 V stimulation threshold with up to 20 mm transmitter-receiver displacement and 20° of misalignment. Feasibility for human use was validated using Finite Element Method (FEM) simulation of the cardiac cycle, guided by pacer phantom-integrated Magnetic Resonance Images (MRI). Conclusion : This system design thus enabled sufficient wireless power transfer in the face of extensive stimulator miniaturization. Significance : Our successful feasibility studies demonstrated the capacity for minimally invasive deployment and low-risk fixation
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