13,701 research outputs found
Electromagnetic interference impact of wireless power transfer system on data wireless channel
Trabalho apresentado no 7th Advanced Doctoral Conference on Computing, Electrical and Industrial Systems, DoCEIS 2016, 11-13 abril 2016, Caparica, PortugalThis paper focuses on measurement and analysis of the electromagnetic fields generated by wireless power transfer system and their possible interaction on data transmission channel. To measure the levels of electromagnetic fields and spectrum near the wireless power transfer equipment the measurement system in the frequency range 100 kHz to 3 GHz was used. Due to the advances in technology it becomes feasible to apply the wireless power transfer in the electric vehicles charging. Currently, in the Faculty of Science and Technology of the University Nova high power wireless power transfer systems are in development. Those systems need to be controlled by several microcontrollers in order to optimize the energy transmission. Their mutual communication is of extreme importance especially when high intensity fields will generate highly undesired influence. The controllers are supposed to communicate with each other through radio frequency data channels. The wireless power transfer system with the electromagnetic interference may influence or completely disrupt the communication which will be a severe problem.N/
Development of Wireless Techniques in Data and Power Transmission - Application for Particle Physics Detectors
Wireless techniques have developed extremely fast over the last decade and
using them for data and power transmission in particle physics detectors is not
science- fiction any more. During the last years several research groups have
independently thought of making it a reality. Wireless techniques became a
mature field for research and new developments might have impact on future
particle physics experiments. The Instrumentation Frontier was set up as a part
of the SnowMass 2013 Community Summer Study [1] to examine the instrumentation
R&D for the particle physics research over the coming decades: {\guillemotleft}
To succeed we need to make technical and scientific innovation a priority in
the field {\guillemotright}. Wireless data transmission was identified as one
of the innovations that could revolutionize the transmission of data out of the
detector. Power delivery was another challenge mentioned in the same report. We
propose a collaboration to identify the specific needs of different projects
that might benefit from wireless techniques. The objective is to provide a
common platform for research and development in order to optimize effectiveness
and cost, with the aim of designing and testing wireless demonstrators for
large instrumentation systems
Implementing and Evaluating a Wireless Body Sensor System for Automated Physiological Data Acquisition at Home
Advances in embedded devices and wireless sensor networks have resulted in
new and inexpensive health care solutions. This paper describes the
implementation and the evaluation of a wireless body sensor system that
monitors human physiological data at home. Specifically, a waist-mounted
triaxial accelerometer unit is used to record human movements. Sampled data are
transmitted using an IEEE 802.15.4 wireless transceiver to a data logger unit.
The wearable sensor unit is light, small, and consumes low energy, which allows
for inexpensive and unobtrusive monitoring during normal daily activities at
home. The acceleration measurement tests show that it is possible to classify
different human motion through the acceleration reading. The 802.15.4 wireless
signal quality is also tested in typical home scenarios. Measurement results
show that even with interference from nearby IEEE 802.11 signals and microwave
ovens, the data delivery performance is satisfactory and can be improved by
selecting an appropriate channel. Moreover, we found that the wireless signal
can be attenuated by housing materials, home appliances, and even plants.
Therefore, the deployment of wireless body sensor systems at home needs to take
all these factors into consideration.Comment: 15 page
Massive MIMO is a Reality -- What is Next? Five Promising Research Directions for Antenna Arrays
Massive MIMO (multiple-input multiple-output) is no longer a "wild" or
"promising" concept for future cellular networks - in 2018 it became a reality.
Base stations (BSs) with 64 fully digital transceiver chains were commercially
deployed in several countries, the key ingredients of Massive MIMO have made it
into the 5G standard, the signal processing methods required to achieve
unprecedented spectral efficiency have been developed, and the limitation due
to pilot contamination has been resolved. Even the development of fully digital
Massive MIMO arrays for mmWave frequencies - once viewed prohibitively
complicated and costly - is well underway. In a few years, Massive MIMO with
fully digital transceivers will be a mainstream feature at both sub-6 GHz and
mmWave frequencies. In this paper, we explain how the first chapter of the
Massive MIMO research saga has come to an end, while the story has just begun.
The coming wide-scale deployment of BSs with massive antenna arrays opens the
door to a brand new world where spatial processing capabilities are
omnipresent. In addition to mobile broadband services, the antennas can be used
for other communication applications, such as low-power machine-type or
ultra-reliable communications, as well as non-communication applications such
as radar, sensing and positioning. We outline five new Massive MIMO related
research directions: Extremely large aperture arrays, Holographic Massive MIMO,
Six-dimensional positioning, Large-scale MIMO radar, and Intelligent Massive
MIMO.Comment: 20 pages, 9 figures, submitted to Digital Signal Processin
Energy-Efficient Power Allocation in OFDM Systems with Wireless Information and Power Transfer
This paper considers an orthogonal frequency division multiplexing (OFDM)
downlink point-to-point system with simultaneous wireless information and power
transfer. It is assumed that the receiver is able to harvest energy from noise,
interference, and the desired signals.
We study the design of power allocation algorithms maximizing the energy
efficiency of data transmission (bit/Joule delivered to the receiver). In
particular, the algorithm design is formulated as a high-dimensional non-convex
optimization problem which takes into account the circuit power consumption,
the minimum required data rate, and a constraint on the minimum power delivered
to the receiver. Subsequently, by exploiting the properties of nonlinear
fractional programming, the considered non-convex optimization problem, whose
objective function is in fractional form, is transformed into an equivalent
optimization problem having an objective function in subtractive form, which
enables the derivation of an efficient iterative power allocation algorithm. In
each iteration, the optimal power allocation solution is derived based on dual
decomposition and a one-dimensional search. Simulation results illustrate that
the proposed iterative power allocation algorithm converges to the optimal
solution, and unveil the trade-off between energy efficiency, system capacity,
and wireless power transfer: (1) In the low transmit power regime, maximizing
the system capacity may maximize the energy efficiency. (2) Wireless power
transfer can enhance the energy efficiency, especially in the interference
limited regime.Comment: 6 pages, Accepted for presentation at the IEEE International
Conference on Communications (ICC) 201
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