360 research outputs found
Survey on wireless technology trade-offs for the industrial internet of things
Aside from vast deployment cost reduction, Industrial Wireless Sensor and Actuator Networks (IWSAN) introduce a new level of industrial connectivity. Wireless connection of sensors and actuators in industrial environments not only enables wireless monitoring and actuation, it also enables coordination of production stages, connecting mobile robots and autonomous transport vehicles, as well as localization and tracking of assets. All these opportunities already inspired the development of many wireless technologies in an effort to fully enable Industry 4.0. However, different technologies significantly differ in performance and capabilities, none being capable of supporting all industrial use cases. When designing a network solution, one must be aware of the capabilities and the trade-offs that prospective technologies have. This paper evaluates the technologies potentially suitable for IWSAN solutions covering an entire industrial site with limited infrastructure cost and discusses their trade-offs in an effort to provide information for choosing the most suitable technology for the use case of interest. The comparative discussion presented in this paper aims to enable engineers to choose the most suitable wireless technology for their specific IWSAN deployment
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
An Analytical Model for Wireless Mesh Networks with Collision-Free TDMA and Finite Queues
Wireless mesh networks are a promising technology for connecting sensors and
actuators with high flexibility and low investment costs. In industrial
applications, however, reliability is essential. Therefore, two time-slotted
medium access methods, DSME and TSCH, were added to the IEEE 802.15.4 standard.
They allow collision-free communication in multi-hop networks and provide
channel hopping for mitigating external interferences. The slot schedule used
in these networks is of high importance for the network performance. This paper
supports the development of efficient schedules by providing an analytical
model for the assessment of such schedules, focused on TSCH. A Markov chain
model for the finite queue on every node is introduced that takes the slot
distribution into account. The models of all nodes are interconnected to
calculate network metrics such as packet delivery ratio, end-to-end delay and
throughput. An evaluation compares the model with a simulation of the Orchestra
schedule. The model is applied to Orchestra as well as to two simple
distributed scheduling algorithms to demonstrate the importance of
traffic-awareness for achieving high throughput.Comment: 17 pages, 14 figure
Modelling and Verification of a Cluster-tree Formation Protocol Implementation for the IEEE 802.15.4 TSCH MAC Operation Mode
Correct and efficient initialization of wireless sensor networks can be
challenging in the face of many uncertainties present in ad hoc wireless
networks. In this paper we examine an implementation for the formation of a
cluster-tree topology in a network which operates on top of the TSCH MAC
operation mode of the IEEE 802.15.4 standard, and investigate it using formal
methods. We show how both the mCRL2 language and toolset help us in identifying
scenarios where the implementation does not form a proper topology. More
importantly, our analysis leads to the conclusion that the cluster-tree
formation algorithm has a super linear time complexity. So, it does not scale
to large networks.Comment: In Proceedings MARS 2017, arXiv:1703.0581
IEEE 802.15.4e: a Survey
Several studies have highlighted that the IEEE 802.15.4 standard presents a number of limitations such as low reliability, unbounded packet delays and no protection against interference/fading, that prevent its adoption in applications with stringent requirements in terms of reliability and latency. Recently, the IEEE has released the 802.15.4e amendment that introduces a number of enhancements/modifications to the MAC layer of the original standard in order to overcome such limitations. In this paper we provide a clear and structured overview of all the new 802.15.4e mechanisms. After a general introduction to the 802.15.4e standard, we describe the details of the main 802.15.4e MAC behavior modes, namely Time Slotted Channel Hopping (TSCH), Deterministic and Synchronous Multi-channel Extension (DSME), and Low Latency Deterministic Network (LLDN). For each of them, we provide a detailed description and highlight the main features and possible application domains. Also, we survey the current literature and summarize open research issues
Analysis of Distributed and Autonomous Scheduling Functions for 6tisch Networks
The 6TiSCH architecture is expected to play a significant role to enable the Internet of Things paradigm also in industrial environments, where reliability and timeliness are of paramount importance to support critical applications. Many research activities have focused on the Scheduling Function (SF) used for managing the allocation of communication resources in order to guarantee the application requirements. Two different approaches have mainly attracted the interest of researchers, namely distributed and autonomous scheduling. Although many different (both distributed and autonomous) SFs have been proposed and analyzed, a direct comparison of these two approaches is still missing. In this work, we compare some different SFs, using different behaviors in allocating resources, and investigate the pros and cons of using distributed or autonomous scheduling in four different scenarios, by means of both simulations and measurements in a real testbed. Based on our results, we also provide a number of guidelines to select the most appropriate SF, and its configuration parameters, depending on the specific use case
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