1,552 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
Joint Uplink and Downlink Coverage Analysis of Cellular-based RF-powered IoT Network
Ambient radio frequency (RF) energy harvesting has emerged as a promising
solution for powering small devices and sensors in massive Internet of Things
(IoT) ecosystem due to its ubiquity and cost efficiency. In this paper, we
study joint uplink and downlink coverage of cellular-based ambient RF energy
harvesting IoT where the cellular network is assumed to be the only source of
RF energy. We consider a time division-based approach for power and information
transmission where each time-slot is partitioned into three sub-slots: (i)
charging sub-slot during which the cellular base stations (BSs) act as RF
chargers for the IoT devices, which then use the energy harvested in this
sub-slot for information transmission and/or reception during the remaining two
sub-slots, (ii) downlink sub-slot during which the IoT device receives
information from the associated BS, and (iii) uplink sub-slot during which the
IoT device transmits information to the associated BS. For this setup, we
characterize the joint coverage probability, which is the joint probability of
the events that the typical device harvests sufficient energy in the given time
slot and is under both uplink and downlink signal-to-interference-plus-noise
ratio (SINR) coverage with respect to its associated BS. This metric
significantly generalizes the prior art on energy harvesting communications,
which usually focused on downlink or uplink coverage separately. The key
technical challenge is in handling the correlation between the amount of energy
harvested in the charging sub-slot and the information signal quality (SINR) in
the downlink and uplink sub-slots. Dominant BS-based approach is developed to
derive tight approximation for this joint coverage probability. Several system
design insights including comparison with regularly powered IoT network and
throughput-optimal slot partitioning are also provided
Wireless sensors and IoT platform for intelligent HVAC control
Energy consumption of buildings (residential and non-residential) represents approximately 40% of total world electricity consumption, with half of this energy consumed by HVAC systems. Model-Based Predictive Control (MBPC) is perhaps the technique most often proposed for HVAC control, since it offers an enormous potential for energy savings. Despite the large number of papers on this topic during the last few years, there are only a few reported applications of the use of MBPC for existing buildings, under normal occupancy conditions and, to the best of our knowledge, no commercial solution yet. A marketable solution has been recently presented by the authors, coined the IMBPC HVAC system. This paper describes the design, prototyping and validation of two components of this integrated system, the Self-Powered Wireless Sensors and the IOT platform developed. Results for the use of IMBPC in a real building under normal occupation demonstrate savings in the electricity bill while maintaining thermal comfort during the whole occupation schedule.QREN SIDT [38798]; Portuguese Foundation for Science & Technology, through IDMEC, under LAETA [ID/EMS/50022/2013
Feasibility of Simultaneous Information and Energy Transfer in LTE-A Small Cell Networks
Simultaneous information and energy transfer is attracting much attention as
an effective method to provide green energy supply for mobiles. However the
very low power level of the harvested energy from RF spectrum limits the
application of such technique. Thanks to the improvement of sensitivity and
efficiency of RF energy harvesting circuit as well as the dense deployment of
small cells base stations, the SIET becomes more practical. In this paper, we
propose a unified receiver model for SIET in LTE-A small cell base staion
networks, formulate the feasibility problem with Poisson point process model
and analysis the feasibility for a special and practical senario. The results
shows that it is feasible for mobiles to charge the secondary battery wih
harvested energy from BSs, but it is still infeasible to directly charge the
primary battery or operate without any battery at all
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