4,092 research outputs found
Subsampling OFDM-based ultrasonic data communication through metallic channels for monitoring of cargo containers
An enhanced ultrasonic communication system based on piezoelectric transducers for monitoring of goods in cargo containers is presented. The proposed system consists of several sensors placed inside the container, whose data are collected and transmitted outside it. Data transmission is carried out by an ultrasonic communication channel, in order to avoid drilling the wall of the container. The proposed data communication system is based on the transmission of a 128-OFDM signal. This modulation has been chosen due to its robustness to channels with frequency-selective fading and its spectrum efficiency. In order to increase the signal bandwidth and to reduce the power consumption at the internal node (transmitter), the proposed system exploits the non-linearity of the metallic channel to transmit at higher resonance frequencies. Moreover, power consumption at the external node (receiver) is reduced by using a subsampling based receiver, which allows its implementation by low-cost electronics.This work was supported by the Spanish Ministry of
Economy and Competitiveness under Projects TEC2016-80396-C2-2-R and TEC2016-80396-C2-1-
Accurate Estimation of a Coil Magnetic Dipole Moment
In this paper, a technique for accurate estimation of the moment of magnetic
dipole is proposed. The achievable accuracy is investigated, as a function of
measurement noise affecting estimation of magnetic field cartesian components.
The proposed technique is validated both via simulations and experimentally.Comment: Preprin
Integrated Sensing and Communications for IoT: Synergies with Key 6G Technology Enablers
The Internet of Things (IoT) and wireless generations have been evolving
simultaneously for the past few decades. Built upon wireless communication and
sensing technologies, IoT networks are usually evaluated based on metrics that
measure the device ability to sense information and effectively share it with
the network, which makes Integrated Sensing and Communication (ISAC) a pivotal
candidate for the sixth-generation (6G) IoT standards. This paper reveals
several innovative aspects of ISAC from an IoT perspective in 6G, empowering
various modern IoT use cases and key technology enablers. Moreover, we address
the challenges and future potential of ISAC-enabled IoT, including synergies
with Reconfigurable Intelligent Surfaces (RIS), Artificial Intelligence (AI),
and key updates of ISAC-IoT in 6G standardization. Furthermore, several
evolutionary concepts are introduced to open future research in 6G ISAC-IoT,
including the interplay with Non-Terrestrial Networks (NTN) and Orthogonal
Time-Frequency Space (OTFS) modulation.Comment: 7 pages, 6 figure
Robotic Wireless Sensor Networks
In this chapter, we present a literature survey of an emerging, cutting-edge,
and multi-disciplinary field of research at the intersection of Robotics and
Wireless Sensor Networks (WSN) which we refer to as Robotic Wireless Sensor
Networks (RWSN). We define a RWSN as an autonomous networked multi-robot system
that aims to achieve certain sensing goals while meeting and maintaining
certain communication performance requirements, through cooperative control,
learning and adaptation. While both of the component areas, i.e., Robotics and
WSN, are very well-known and well-explored, there exist a whole set of new
opportunities and research directions at the intersection of these two fields
which are relatively or even completely unexplored. One such example would be
the use of a set of robotic routers to set up a temporary communication path
between a sender and a receiver that uses the controlled mobility to the
advantage of packet routing. We find that there exist only a limited number of
articles to be directly categorized as RWSN related works whereas there exist a
range of articles in the robotics and the WSN literature that are also relevant
to this new field of research. To connect the dots, we first identify the core
problems and research trends related to RWSN such as connectivity,
localization, routing, and robust flow of information. Next, we classify the
existing research on RWSN as well as the relevant state-of-the-arts from
robotics and WSN community according to the problems and trends identified in
the first step. Lastly, we analyze what is missing in the existing literature,
and identify topics that require more research attention in the future
Device-free indoor localisation with non-wireless sensing techniques : a thesis by publications presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Electronics and Computer Engineering, Massey University, Albany, New Zealand
Global Navigation Satellite Systems provide accurate and reliable outdoor positioning to support a large number of applications across many sectors. Unfortunately, such systems do not operate reliably inside buildings due to the signal degradation caused by the absence of a clear line of sight with the satellites. The past two decades have therefore seen intensive research into the development of Indoor Positioning System (IPS). While considerable progress has been made in the indoor localisation discipline, there is still no widely adopted solution. The proliferation of Internet of Things (IoT) devices within the modern built environment provides an opportunity to localise human subjects by utilising such ubiquitous networked devices. This thesis presents the development, implementation and evaluation of several passive indoor positioning systems using ambient Visible Light Positioning (VLP), capacitive-flooring, and thermopile sensors (low-resolution thermal cameras). These systems position the human subject in a device-free manner (i.e., the subject is not required to be instrumented). The developed systems improve upon the state-of-the-art solutions by offering superior position accuracy whilst also using more robust and generalised test setups. The developed passive VLP system is one of the first reported solutions making use of ambient light to position a moving human subject. The capacitive-floor based system improves upon the accuracy of existing flooring solutions as well as demonstrates the potential for automated fall detection. The system also requires very little calibration, i.e., variations of the environment or subject have very little impact upon it. The thermopile positioning system is also shown to be robust to changes in the environment and subjects. Improvements are made over the current literature by testing across multiple environments and subjects whilst using a robust ground truth system. Finally, advanced machine learning methods were implemented and benchmarked against a thermopile dataset which has been made available for other researchers to use
Publications of the Jet Propulsion Laboratory 1987
A bibliography is presented which describes and indexes by author the externally distributed technical reporting, released during the calender year 1987, that resulted from scientific and engineering work performed, or managed, by the Jet Propulsion Lab. Three classes of publications are included: (1) JPL publications in which the information is complete for a specific accomplishment; (2) Articles from the quarterly Telecommunications and Data Acquisition Progress Report; and (3) Articles published in the open literature
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