4,275 research outputs found
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
Wireless Power Transfer and Data Collection in Wireless Sensor Networks
In a rechargeable wireless sensor network, the data packets are generated by
sensor nodes at a specific data rate, and transmitted to a base station.
Moreover, the base station transfers power to the nodes by using Wireless Power
Transfer (WPT) to extend their battery life. However, inadequately scheduling
WPT and data collection causes some of the nodes to drain their battery and
have their data buffer overflow, while the other nodes waste their harvested
energy, which is more than they need to transmit their packets. In this paper,
we investigate a novel optimal scheduling strategy, called EHMDP, aiming to
minimize data packet loss from a network of sensor nodes in terms of the nodes'
energy consumption and data queue state information. The scheduling problem is
first formulated by a centralized MDP model, assuming that the complete states
of each node are well known by the base station. This presents the upper bound
of the data that can be collected in a rechargeable wireless sensor network.
Next, we relax the assumption of the availability of full state information so
that the data transmission and WPT can be semi-decentralized. The simulation
results show that, in terms of network throughput and packet loss rate, the
proposed algorithm significantly improves the network performance.Comment: 30 pages, 8 figures, accepted to IEEE Transactions on Vehicular
Technolog
Wireless Information and Power Transfer in Full-Duplex Systems with Massive Antenna Arrays
We consider a multiuser wireless system with a full-duplex hybrid access
point (HAP) that transmits to a set of users in the downlink channel, while
receiving data from a set of energy-constrained sensors in the uplink channel.
We assume that the HAP is equipped with a massive antenna array, while all
users and sensor nodes have a single antenna. We adopt a time-switching
protocol where in the first phase, sensors are powered through wireless energy
transfer from HAP and HAP estimates the downlink channel of the users. In the
second phase, sensors use the harvested energy to transmit to the HAP. The
downlink-uplink sum-rate region is obtained by solving downlink sum-rate
maximization problem under a constraint on uplink sum-rate. Moreover, assuming
perfect and imperfect channel state information, we derive expressions for the
achievable uplink and downlink rates in the large-antenna limit and approximate
results that hold for any finite number of antennas. Based on these analytical
results, we obtain the power-scaling law and analyze the effect of the number
of antennas on the cancellation of intra-user interference and the
self-interference.Comment: Accepted for the IEEE International Conference on Communications (ICC
2017
Joint Wireless Information and Energy Transfer in a K-User MIMO Interference Channel
Recently, joint wireless information and energy transfer (JWIET) methods have
been proposed to relieve the battery limitation of wireless devices. However,
the JWIET in a general K-user MIMO interference channel (IFC) has been
unexplored so far. In this paper, we investigate for the first time the JWIET
in K-user MIMO IFC, in which receivers either decode the incoming information
data (information decoding, ID) or harvest the RF energy (energy harvesting,
EH). In the K-user IFC, we consider three different scenarios according to the
receiver mode -- i) multiple EH receivers and a single ID receiver, ii)
multiple IDs and a single EH, and iii) multiple IDs and multiple EHs. For all
scenarios, we have found a common necessary condition of the optimal
transmission strategy and, accordingly, developed the transmission strategy
that satisfies the common necessary condition, in which all the transmitters
transferring energy exploit a rank-one energy beamforming. Furthermore, we have
also proposed an iterative algorithm to optimize the covariance matrices of the
transmitters that transfer information and the powers of the energy beamforming
transmitters simultaneously, and identified the corresponding achievable
rate-energy tradeoff region. Finally, we have shown that by selecting EH
receivers according to their signal-to-leakage-and-harvested energy-ratio
(SLER), we can improve the achievable rate-energy region further.Comment: arXiv admin note: text overlap with arXiv:1303.169
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