3,636 research outputs found
A Low Energy FPGA Platform for Real-Time Event-Based Control
We present a wireless sensor node suitable for event-based real-time control networks. The node achieves low-power operation thanks to tight clock synchronisation with the network master (at present we refer to a star network but extensions are envisaged). Also, the node does not employ any programmable device but rather an FPGA, thus being inherently immune to attacks based on code tampering. Experimental results on a simple laboratory apparatus are presented
Proposition and validation of an original MAC layer with simultaneous medium accesses for low latency wireless control/command applications
Control/command processes require a transmission system with some
characteristics like high reliability, low latency and strong guarantees on
messages delivery. Concerning wire networks, field buses technologies like FIP
offer this kind of service (periodic tasks, real time constraints...).
Unfortunately, few wireless technologies can propose a communication system
which respects such constraints. Indeed, wireless transmissions must deal with
medium characteristics which make impossible the direct translation of
mechanisms used with wire networks. The purpose of this paper is to present an
original Medium Access Control (MAC) layer for a real time Low Power-Wireless
Personal Area Network (LP-WPAN). The proposed MAC-layer has been validated by
several complementary methods; in this paper, we focus on the specific
Simultaneous Guaranteed Time Slot (SGTS) part
A Case for Time Slotted Channel Hopping for ICN in the IoT
Recent proposals to simplify the operation of the IoT include the use of
Information Centric Networking (ICN) paradigms. While this is promising,
several challenges remain. In this paper, our core contributions (a) leverage
ICN communication patterns to dynamically optimize the use of TSCH (Time
Slotted Channel Hopping), a wireless link layer technology increasingly popular
in the IoT, and (b) make IoT-style routing adaptive to names, resources, and
traffic patterns throughout the network--both without cross-layering. Through a
series of experiments on the FIT IoT-LAB interconnecting typical IoT hardware,
we find that our approach is fully robust against wireless interference, and
almost halves the energy consumed for transmission when compared to CSMA. Most
importantly, our adaptive scheduling prevents the time-slotted MAC layer from
sacrificing throughput and delay
A Study of Medium Access Control Protocols for Wireless Body Area Networks
The seamless integration of low-power, miniaturised, invasive/non-invasive
lightweight sensor nodes have contributed to the development of a proactive and
unobtrusive Wireless Body Area Network (WBAN). A WBAN provides long-term health
monitoring of a patient without any constraint on his/her normal dailylife
activities. This monitoring requires low-power operation of
invasive/non-invasive sensor nodes. In other words, a power-efficient Medium
Access Control (MAC) protocol is required to satisfy the stringent WBAN
requirements including low-power consumption. In this paper, we first outline
the WBAN requirements that are important for the design of a low-power MAC
protocol. Then we study low-power MAC protocols proposed/investigated for WBAN
with emphasis on their strengths and weaknesses. We also review different
power-efficient mechanisms for WBAN. In addition, useful suggestions are given
to help the MAC designers to develop a low-power MAC protocol that will satisfy
the stringent WBAN requirements.Comment: 13 pages, 8 figures, 7 table
Cross-layer energy optimisation of routing protocols in wireless sensor networks
Recent technological developments in embedded systems have led to the emergence of a new class of networks, known asWireless Sensor Networks (WSNs), where individual nodes cooperate wirelessly with each other with the goal of sensing and interacting with the environment.Many routing protocols have been developed tomeet the unique and challenging characteristics of WSNs (notably very limited power resources to sustain an expected lifetime of perhaps
years, and the restricted computation, storage and communication capabilities of nodes that are nonetheless required to support large networks and diverse applications). No standards for routing have been developed yet for WSNs, nor has any protocol gained a dominant position among the research community.
Routing has a significant influence on the overall WSN lifetime, and providing an energy efficient routing protocol remains an open problem. This thesis addresses
the issue of designing WSN routing methods that feature energy efficiency. A common time reference across nodes is required in mostWSN applications. It is needed, for example, to time-stamp sensor samples and for duty cycling of nodes. Alsomany routing protocols require that nodes communicate according to some predefined schedule. However, independent distribution of the time information, without considering the routing algorithm schedule or network topology may lead to a failure of the synchronisation protocol. This was confirmed empirically, and was shown to result in loss of connectivity. This can be avoided by
integrating the synchronisation service into the network layer with a so-called cross-layer approach. This approach introduces interactions between the layers of a conventional layered network stack, so that the routing layer may share information with other layers. I explore whether energy efficiency can be enhanced through the use of cross-layer optimisations and present three novel cross-layer routing algorithms. The first protocol, designed for hierarchical, cluster based networks
and called CLEAR (Cross Layer Efficient Architecture for Routing), uses the routing algorithm to distribute time information which can be used for efficient duty cycling of nodes. The second method - called RISS (Routing Integrated
Synchronization Service) - integrates time synchronization into the network layer and is designed to work well in flat, non-hierarchical network topologies. The third method - called SCALE (Smart Clustering Adapted LEACH) - addresses
the influence of the intra-cluster topology on the energy dissipation of nodes. I also investigate the impact of the hop distance on network lifetime and propose a method of determining the optimal location of the relay node (the node through which data is routed in a two-hop network). I also address the problem of predicting the transition region (the zone separating the region where all packets
can be received and that where no data can be received) and I describe a way of preventing the forwarding of packets through relays belonging in this transition region.
I implemented and tested the performance of these solutions in simulations and also deployed these routing techniques on sensor nodes using TinyOS. I compared the average power consumption of the nodes and the precision of time synchronization with the corresponding parameters of a number of existing algorithms. All proposed schemes extend the network lifetime and due to their lightweight architecture they are very efficient on WSN nodes with constrained resources. Hence it is recommended that a cross-layer approach should be a feature of any routing algorithm for WSNs
Bio-Inspired Tools for a Distributed Wireless Sensor Network Operating System
The problem which I address in this thesis is to find a way to organise and manage a network
of wireless sensor nodes using a minimal amount of communication. To find a solution I explore
the use of Bio-inspired protocols to enable WSN management while maintaining a low
communication overhead. Wireless Sensor Networks (WSNs) are loosely coupled distributed
systems comprised of low-resource, battery powered sensor nodes. The largest problem with
WSN management is that communication is the largest consumer of a sensor nodeâs energy.
WSN management systems need to use as little communication as possible to prolong their operational
lifetimes. This is the Wireless Sensor Network Management Problem. This problem
is compounded because current WSN management systems glue together unrelated protocols
to provide system services causing inter-protocol interference. Bio-inspired protocols provide a
good solution because they enable the nodes to self-organise, use local area communication, and
can combine their communication in an intelligent way with minimal increase in communication.
I present a combined protocol and MAC scheduler to enable multiple service protocols to
function in a WSN at the same time without causing inter-protocol interference. The scheduler
is throughput optimal as long as the communication requirements of all of the protocols remain
within the communication capacity of the network. I show that the scheduler improves a dissemination
protocolâs performance by 35%. A bio-inspired synchronisation service is presented
which enables wireless sensor nodes to self organise and provide a time service. Evaluation of
the protocol shows an 80% saving in communication over similar bio-inspired synchronisation
approaches. I then add an information dissemination protocol, without significantly increasing
communication. This is achieved through the ability of our bio-inspired algorithms to combine
their communication in an intelligent way so that they are able to offer multiple services
without requiring a great deal of inter-node communication.Open Acces
A survey on subjecting electronic product code and non-ID objects to IP identification
Over the last decade, both research on the Internet of Things (IoT) and
real-world IoT applications have grown exponentially. The IoT provides us with
smarter cities, intelligent homes, and generally more comfortable lives.
However, the introduction of these devices has led to several new challenges
that must be addressed. One of the critical challenges facing interacting with
IoT devices is to address billions of devices (things) around the world,
including computers, tablets, smartphones, wearable devices, sensors, and
embedded computers, and so on. This article provides a survey on subjecting
Electronic Product Code and non-ID objects to IP identification for IoT
devices, including their advantages and disadvantages thereof. Different
metrics are here proposed and used for evaluating these methods. In particular,
the main methods are evaluated in terms of their: (i) computational overhead,
(ii) scalability, (iii) adaptability, (iv) implementation cost, and (v) whether
applicable to already ID-based objects and presented in tabular format.
Finally, the article proves that this field of research will still be ongoing,
but any new technique must favorably offer the mentioned five evaluative
parameters.Comment: 112 references, 8 figures, 6 tables, Journal of Engineering Reports,
Wiley, 2020 (Open Access
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