2,073 research outputs found
Reconfigurable Antenna Systems: Platform implementation and low-power matters
Antennas are a necessary and often critical component of all wireless systems, of which they share the ever-increasing complexity and the challenges of present and emerging trends. 5G, massive low-orbit satellite architectures (e.g. OneWeb), industry 4.0, Internet of Things (IoT), satcom on-the-move, Advanced Driver Assistance Systems (ADAS) and Autonomous Vehicles, all call for highly flexible systems, and antenna reconfigurability is an enabling part of these advances. The terminal segment is particularly crucial in this sense, encompassing both very compact antennas or low-profile antennas, all with various adaptability/reconfigurability requirements. This thesis work has dealt with hardware implementation issues of Radio Frequency (RF) antenna reconfigurability, and in particular with low-power General Purpose Platforms (GPP); the work has encompassed Software Defined Radio (SDR) implementation, as well as embedded low-power platforms (in particular on STM32 Nucleo family of micro-controller). The hardware-software platform work has been complemented with design and fabrication of reconfigurable antennas in standard technology, and the resulting systems tested. The selected antenna technology was antenna array with continuously steerable beam, controlled by voltage-driven phase shifting circuits. Applications included notably Wireless Sensor Network (WSN) deployed in the Italian scientific mission in Antarctica, in a traffic-monitoring case study (EU H2020 project), and into an innovative Global Navigation Satellite Systems (GNSS) antenna concept (patent application submitted). The SDR implementation focused on a low-cost and low-power Software-defined radio open-source platform with IEEE 802.11 a/g/p wireless communication capability. In a second embodiment, the flexibility of the SDR paradigm has been traded off to avoid the power consumption associated to the relevant operating system. Application field of reconfigurable antenna is, however, not limited to a better management of the energy consumption. The analysis has also been extended to satellites positioning application. A novel beamforming method has presented demonstrating improvements in the quality of signals received from satellites. Regarding those who deal with positioning algorithms, this advancement help improving precision on the estimated position
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Dynamic Recofiguration Techniques for Wireless Sensor Networks
The need to achieve extended service life by battery powered Wireless Sensor Networks (WSNs) requires new concepts and technqiues beyond the state-of-the-art low-power designs based on fixed hardware platforms or energy-efficient protocols. This thesis investigates reconfiguration techniques that enable sensor hardware to adapt its energy consumption to external dynamics, by means of Dynamic Voltage Scaling (DVS), Dynamic Modulation Scaling (DMS), and other related concepts. For sensor node-level reconfiguration, an integration of DVS and DMS techniques was proposed to minimize the total energy consumption. A dynamic time allocation algorithm was developed, demonstrating an average of 55% energy reduction. For network-level reconfiguration, a node activation technique was presented to reduce the cost of recharging energy-depleted sensor nodes. Network operation combined with node activation was modeled as a stochastic decision process, where the activation decisions directly affected the energy efficiency of the network. An experimental test bed based on the Imote2 sensor node platform was realized, which demonstrated energy reduction of up to 50%. Such energy saving can be effectively translated into prolonged service life of the sensor network
Acoustic Communication Networks for Distributed Autonomous Underwater Platforms: Progress Report
The ultimate goal of this project is to design and develop an experimental platform for testing and evaluation of mobile underwater acoustic networking. This report represents a cumulative summary of research and engineering efforts pursued from the beginning of the project up to this date.
The project has focused on three topics:
1. Design and performance analysis of communication protocols for mobile acoustic networks;
2. Development of the software-defined reconfigurable acoustic modem; and
3. Design and development of a small autonomous underwater vehicle (the micro AUV)
The Design of a System Architecture for Mobile Multimedia Computers
This chapter discusses the system architecture of a portable computer, called Mobile Digital Companion, which provides support for handling multimedia applications energy efficiently. Because battery life is limited and battery weight is an important factor for the size and the weight of the Mobile Digital Companion, energy management plays a crucial role in the architecture. As the Companion must remain usable in a variety of environments, it has to be flexible and adaptable to various operating conditions. The Mobile Digital Companion has an unconventional architecture that saves energy by using system decomposition at different levels of the architecture and exploits locality of reference with dedicated, optimised modules. The approach is based on dedicated functionality and the extensive use of energy reduction techniques at all levels of system design. The system has an architecture with a general-purpose processor accompanied by a set of heterogeneous autonomous programmable modules, each providing an energy efficient implementation of dedicated tasks. A reconfigurable internal communication network switch exploits locality of reference and eliminates wasteful data copies
YodaNN: An Architecture for Ultra-Low Power Binary-Weight CNN Acceleration
Convolutional neural networks (CNNs) have revolutionized the world of
computer vision over the last few years, pushing image classification beyond
human accuracy. The computational effort of today's CNNs requires power-hungry
parallel processors or GP-GPUs. Recent developments in CNN accelerators for
system-on-chip integration have reduced energy consumption significantly.
Unfortunately, even these highly optimized devices are above the power envelope
imposed by mobile and deeply embedded applications and face hard limitations
caused by CNN weight I/O and storage. This prevents the adoption of CNNs in
future ultra-low power Internet of Things end-nodes for near-sensor analytics.
Recent algorithmic and theoretical advancements enable competitive
classification accuracy even when limiting CNNs to binary (+1/-1) weights
during training. These new findings bring major optimization opportunities in
the arithmetic core by removing the need for expensive multiplications, as well
as reducing I/O bandwidth and storage. In this work, we present an accelerator
optimized for binary-weight CNNs that achieves 1510 GOp/s at 1.2 V on a core
area of only 1.33 MGE (Million Gate Equivalent) or 0.19 mm and with a power
dissipation of 895 {\mu}W in UMC 65 nm technology at 0.6 V. Our accelerator
significantly outperforms the state-of-the-art in terms of energy and area
efficiency achieving 61.2 TOp/s/[email protected] V and 1135 GOp/s/[email protected] V, respectively
FPGA based reconfigurable body area network using Nios II and uClinux
This research is focused on identifying an appropriate design for a reconfigurable
Body Area Network (BAN).
In order to investigate the benefits and drawbacks of the proposed design, a BAN
system prototype was built. This system consists of two distinct node types: a slave
node and a master node. These nodes communicate using ZigBee radio transceivers.
The microcontroller-based slave node acquires sensor data and transmits digitized
samples to the master node. The master node is FPGA-based and runs uClinux on
a soft-core microcontroller. The purpose of the master node is to receive, process
and store digitized sensor data. In order to verify the operation of the BAN system
prototype and demonstrate reconfigurability, a specific application was required.
Pattern recognition in electrocardiogram (ECG) data was the application used in
this work and the MIT-BIH Arrhythmia Database was used as the known data source
for verification. A custom test platform was designed and built for the purpose of
injecting data from the MIT-BIH Arrhythmia Database into the BAN system.
The BAN system designed and built in this work demonstrates the ability to record
raw ECG data, detect R-peaks, calculate and record R-R intervals, detect premature
ventricular and atrial contractions. As this thesis will identify, many aspects of this
BAN system were designed to be highly reconfigurable allowing it to be used for a
wide range of BAN applications, in addition to pattern recognition of ECG data
Developing a neighborhood-scale wireless notification prototype
We outline an innovative approach to thedevelopment of a prototype of a neighborhoodnotification system (NNS). The NNS applicationresiding on smart phones will use software definedradio and cognitive radio components to interfacewith radio frequency transceivers. Mesh networkingis proposed for emergency notification and disasterresponse coordination using NNS. Our focus hasbeen on the IEEE 802.15.4 and the very recent IEEE802.15.5 mesh networking standard for low data rateconnectivity among low power nodes (or nodeswhose power consumption needs to be low). Theinnovation stems from bringing together differenthardware and software components – some of which,like our Software Defined Radio (SDR) platform, arethemselves still evolving and others, like themeshing platform, are very new – to propose anadaptive, reconfigurable, infrastructure-less ad hocwireless solution to emergency communications inthe unlicensed ISM RF band
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