28,223 research outputs found
Optimal Multiuser Scheduling Schemes for Simultaneous Wireless Information and Power Transfer
In this paper, we study the downlink multiuser scheduling problem for systems
with simultaneous wireless information and power transfer (SWIPT). We design
optimal scheduling algorithms that maximize the long-term average system
throughput under different fairness requirements, such as proportional fairness
and equal throughput fairness. In particular, the algorithm designs are
formulated as non-convex optimization problems which take into account the
minimum required average sum harvested energy in the system. The problems are
solved by using convex optimization techniques and the proposed optimization
framework reveals the tradeoff between the long-term average system throughput
and the sum harvested energy in multiuser systems with fairness constraints.
Simulation results demonstrate that substantial performance gains can be
achieved by the proposed optimization framework compared to existing suboptimal
scheduling algorithms from the literature.Comment: Accepted for presentation at the European Signal Processing
Conference 201
Multi-user Scheduling Schemes for Simultaneous Wireless Information and Power Transfer
In this paper, we study the downlink multi-user scheduling problem for a
time-slotted system with simultaneous wireless information and power transfer.
In particular, in each time slot, a single user is scheduled to receive
information, while the remaining users opportunistically harvest the ambient
radio frequency (RF) energy. We devise novel scheduling schemes in which the
tradeoff between the users' ergodic capacities and their average amount of
harvested energy can be controlled. To this end, we modify two fair scheduling
schemes used in information-only transfer systems. First, proportionally fair
maximum normalized signal-to-noise ratio (N-SNR) scheduling is modified by
scheduling the user having the jth ascendingly ordered (rather than the
maximum) N-SNR. We refer to this scheme as order-based N-SNR scheduling.
Second, conventional equal-throughput (ET) fair scheduling is modified by
scheduling the user having the minimum moving average throughput among the set
of users whose N-SNR orders fall into a certain set of allowed orders Sa
(rather than the set of all users). We refer to this scheme as order-based ET
scheduling. The feasibility conditions required for the users to achieve ET
with this scheme are also derived. We show that the smaller the selection order
j for the order-based N-SNR scheme, and the lower the orders in Sa for the
order-based ET scheme, the higher the average amount of energy harvested by the
users at the expense of a reduction in their ergodic capacities. We analyze the
performance of the considered scheduling schemes for independent and
non-identically distributed (i.n.d.) Ricean fading channels, and provide
closed-form results for the special case of i.n.d. Rayleigh fading.Comment: 6 pages, 3 figures. Submitted for possible conference publicatio
Power Allocation and Scheduling for SWIPT Systems with Non-linear Energy Harvesting Model
In this paper, we design a resource allocation algorithm for multiuser
simultaneous wireless information and power transfer systems for a realistic
non-linear energy harvesting (EH) model. In particular, the algorithm design is
formulated as a non-convex optimization problem for the maximization of the
long-term average total harvested power at EH receivers subject to quality of
service requirements for information decoding receivers. To obtain a tractable
solution, we transform the corresponding non-convex sum-of-ratios objective
function into an equivalent objective function in parametric subtractive form.
This leads to a computationally efficient iterative resource allocation
algorithm. Numerical results reveal a significant performance gain that can be
achieved if the resource allocation algorithm design is based on the non-linear
EH model instead of the traditional linear model.Comment: Accepted for presentation at the IEEE ICC 201
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