Wireless industrial monitoring and control networks: the journey so far and the road ahead

While traditional wired communication technologies have played a crucial role in industrial monitoring and control networks over the past few decades, they are increasingly proving to be inadequate to meet the highly dynamic and stringent demands of today’s industrial applications, primarily due to the very rigid nature of wired infrastructures. Wireless technology, however, through its increased pervasiveness, has the potential to revolutionize the industry, not only by mitigating the problems faced by wired solutions, but also by introducing a completely new class of applications. While present day wireless technologies made some preliminary inroads in the monitoring domain, they still have severe limitations especially when real-time, reliable distributed control operations are concerned. This article provides the reader with an overview of existing wireless technologies commonly used in the monitoring and control industry. It highlights the pros and cons of each technology and assesses the degree to which each technology is able to meet the stringent demands of industrial monitoring and control networks. Additionally, it summarizes mechanisms proposed by academia, especially serving critical applications by addressing the real-time and reliability requirements of industrial process automation. The article also describes certain key research problems from the physical layer communication for sensor networks and the wireless networking perspective that have yet to be addressed to allow the successful use of wireless technologies in industrial monitoring and control networks

Distributed Time Division Multiple Access (DTDMA) Medium Access Control Protocol For Wireless Sensor Networks [TK7872.D48 W872 2008 f rb].

Rangkaian sensor tanpa wayar menerima perhatian yang memberangsangkan sejak beberapa tahun yang lalu disebabkan oleh peningkatan permintaan terhadap perisian kadar rendah, murah dan menjimatkan tenaga seperti operasi perkilangan, ketenteraan, kesihatan, pengawasan alam sekitar, sekuriti, operasi penyelamatan dan komunikasi tanpa wayar. Wireless Sensor Networks (WSNs) received tremendous attention over the last few years due to increasing demand for low data rate, low-cost and low power applications in industries like factory automation, military, health and hospitality,environment monitoring, security, search and rescue, and wireless communications

Availability and End-to-end Reliability in Low Duty Cycle Multihop Wireless Sensor Networks

A wireless sensor network (WSN) is an ad-hoc technology that may even consist of thousands of nodes, which necessitates autonomic, self-organizing and multihop operations. A typical WSN node is battery powered, which makes the network lifetime the primary concern. The highest energy efficiency is achieved with low duty cycle operation, however, this alone is not enough. WSNs are deployed for different uses, each requiring acceptable Quality of Service (QoS). Due to the unique characteristics of WSNs, such as dynamic wireless multihop routing and resource constraints, the legacy QoS metrics are not feasible as such. We give a new definition to measure and implement QoS in low duty cycle WSNs, namely availability and reliability. Then, we analyze the effect of duty cycling for reaching the availability and reliability. The results are obtained by simulations with ZigBee and proprietary TUTWSN protocols. Based on the results, we also propose a data forwarding algorithm suitable for resource constrained WSNs that guarantees end-to-end reliability while adding a small overhead that is relative to the packet error rate (PER). The forwarding algorithm guarantees reliability up to 30% PER

Interference mitigation strategy design and applications for wireless sensor networks

The Institute of Electrical and Electronics Engineers (IEEE) 802.15.4 standard presents a very useful technology for implementing low-cost, low-power, wireless sensor networks. Its main focus, which is to applications requiring simple wireless connectivity with relaxed throughout and latency requirements, makes it suitable for connecting devices that have not been networked, such as industrial and control instrumentation equipments, agricultural equipments, vehicular equipments, and home appliances. Its usage of the license-free 2.4 GHz frequency band makes the technique successful for fast and worldwide market deployments. However, concerns about interference have arisen due to the presence of other wireless technologies using the same spectrum. Although the IEEE 802.15.4 standard has provided some mechanisms, to enhance capability to coexist with other wireless devices operating on the same frequency band, including Carrier Sensor Multiple Access (CSMA), Clear Channel Assessment (CCA), channel alignment, and low duty cycle, it is essential to design and implement adjustable mechanisms for an IEEE 802.15.4 based system integrated into a practical application to deal with interference which changes randomly over time. Among the potential interfering systems (Wi-Fi, Bluetooth, cordless phones, microwave ovens, wireless headsets, etc) which work on the same Industrial, Scientific, and Medical (ISM) frequency band, Wi-Fi systems (IEEE 802.11 technique) have attracted most concerns because of their high transmission power and large deployment in both residential and office environments. This thesis aims to propose a methodology for IEEE 802.15.4 wireless systems to adopt proper adjustment in order to mitigate the effect of interference caused by IEEE 802.11 systems through energy detection, channel agility and data recovery. The contribution of this thesis consists of five parts. Firstly, a strategy is proposed to enable IEEE 802.15.4 systems to maintain normal communications using the means of consecutive transmissions, when the system s default mechanism of retransmission is insufficient to ensure successful rate due to the occurrence of Wi-Fi interference. Secondly, a novel strategy is proposed to use a feasible way for IEEE 802.15.4 systems to estimate the interference pattern, and accordingly adjust system parameters for the purpose of achieving optimized communication effectiveness during time of interference without relying on hardware changes and IEEE 802.15.4 protocol modifications. Thirdly, a data recovery mechanism is proposed for transport control to be applied for recovering lost data by associating with the proposed strategies to ensure the data integrity when IEEE 802.15.4 systems are suffering from interference. Fourthly, a practical case is studied to discuss how to design a sustainable system for home automation application constructed on the basis of IEEE 802.15.4 technique. Finally, a comprehensive design is proposed to enable the implementation of an interference mitigation strategy for IEEE 802.15.4 based ad hoc WSNs within a structure of building fire safety monitoring system. The proposed strategies and system designs are demonstrated mainly through theoretical analysis and experimental tests. The results obtained from the experimental tests have verified that the interference caused by an IEEE 802.11 system on an IEEE 802.15.4 system can be effectively mitigated through adjusting IEEE 802.15.4 system s parameters cooperating with interference pattern estimation. The proposed methods are suitable to be integrated into a system-level solution for an IEEE 802.15.4 system to deal with interference, which is also applicable to those wireless systems facing similar interference issues to enable the development of efficient mitigation strategies

Wireless Sensor Networks

The aim of this book is to present few important issues of WSNs, from the application, design and technology points of view. The book highlights power efficient design issues related to wireless sensor networks, the existing WSN applications, and discusses the research efforts being undertaken in this field which put the reader in good pace to be able to understand more advanced research and make a contribution in this field for themselves. It is believed that this book serves as a comprehensive reference for graduate and undergraduate senior students who seek to learn latest development in wireless sensor networks

A Comprehensive Approach to WSN-Based ITS Applications: A Survey

In order to perform sensing tasks, most current Intelligent Transportation Systems (ITS) rely on expensive sensors, which offer only limited functionality. A more recent trend consists of using Wireless Sensor Networks (WSN) for such purpose, which reduces the required investment and enables the development of new collaborative and intelligent applications that further contribute to improve both driving safety and traffic efficiency. This paper surveys the application of WSNs to such ITS scenarios, tackling the main issues that may arise when developing these systems. The paper is divided into sections which address different matters including vehicle detection and classification as well as the selection of appropriate communication protocols, network architecture, topology and some important design parameters. In addition, in line with the multiplicity of different technologies that take part in ITS, it does not consider WSNs just as stand-alone systems, but also as key components of heterogeneous systems cooperating along with other technologies employed in vehicular scenarios

IEEE 802.15.4: a Federating Communication Protocol for Time-Sensitive Wireless Sensor Networks

Wireless Sensor Networks (WSNs) have been attracting increasing interests for developing a new generation of embedded systems with great potential for many applications such as surveillance, environment monitoring, emergency medical response and home automation. However, the communication paradigms in WSNs differ from the ones attributed to traditional wireless networks, triggering the need for new communication protocols. In this context, the recently standardised IEEE 802.15.4 protocol presents some potentially interesting features for deployment in wireless sensor network applications, such as power-efficiency, timeliness guarantees and scalability. Nevertheless, when addressing WSN applications with (soft/hard) timing requirements some inherent paradoxes emerge, such as power-efficiency versus timeliness, triggering the need of engineering solutions for an efficient deployment of IEEE 802.15.4 in WSNs. In this technical report, we will explore the most relevant characteristics of the IEEE 802.15.4 protocol for wireless sensor networks and present the most important challenges regarding time-sensitive WSN applications. We also provide some timing performance and analysis of the IEEE 802.15.4 that unveil some directions for resolving the previously mentioned paradoxes

Using genetic algorithms to optimise Wireless Sensor Network design

Wireless Sensor Networks(WSNs) have gained a lot of attention because of their potential to immerse deeper into people' lives. The applications of WSNs range from small home environment networks to large habitat monitoring. These highly diverse scenarios impose different requirements on WSNs and lead to distinct design and implementation decisions. This thesis presents an optimization framework for WSN design which selects a proper set of protocols and number of nodes before a practical network deployment. A Genetic Algorithm(GA)-based Sensor Network Design Tool(SNDT) is proposed in this work for wireless sensor network design in terms of performance, considering application-specific requirements, deployment constrains and energy characteristics. SNDT relies on offine simulation analysis to help resolve design decisions. A GA is used as the optimization tool of the proposed system and an appropriate fitness function is derived to incorporate many aspects of network performance. The configuration attributes optimized by SNDT comprise the communication protocol selection and the number of nodes deployed in a fixed area. Three specific cases : a periodic-measuring application, an event detection type of application and a tracking-based application are considered to demonstrate and assess how the proposed framework performs. Considering the initial requirements of each case, the solutions provided by SNDT were proven to be favourable in terms of energy consumption, end-to-end delay and loss. The user-defined application requirements were successfully achieved