Communication In Industrial Environments Research Articles

End-to-End No-wait Scheduling for Time-Triggered Streams in Mixed Wired-Wireless Networks

Proprietary communication technologies for time-critical communication in industrial environments are being gradually replaced by Time-sensitive Networking (TSN)-enabled Ethernet. Furthermore, attempts have been made to bring TSN features into wireless networks so that the flexibility of wireless networks can be utilized, and the end-to-end timings for Time-Triggered (TT) streams can be guaranteed. Given a mixed wired-wireless network, the scheduling problem should be solved for a set of TT stream requests. In this paper, we formulate the no-wait scheduling problem for mixed wired-wireless networks as a Mixed Integer Linear Programming (MILP) model with the objective of minimizing the flowspan. We also propose a relaxation of the original MILP in the form of a 2-stage MILP formulation. Next, a scalable approach based on the greedy heuristic is proposed to solve the problem for realistic-size networks. Evaluation results show that the greedy heuristic is suitable for realistic problem sizes where the MILP-based approach is found to be practically infeasible. Furthermore, the impact of wireless requests on the performance of the greedy heuristic is reported.

End-to-End No-wait Scheduling for Time-Triggered Streams in Mixed Wired-Wireless Networks

Proprietary communication technologies for time-critical communication in industrial environments are being gradually replaced by Time-sensitive Networking (TSN)-enabled Ethernet. Furthermore, attempts have been made to bring TSN features into wireless networks so that the flexibility of wireless networks can be utilized, and the end-to-end timings for Time-Triggered (TT) streams can be guaranteed. Given a mixed wired-wireless network, the scheduling problem should be solved for a set of TT stream requests. In this paper, we formulate the no-wait scheduling problem for mixed wired-wireless networks as a Mixed Integer Linear Programming (MILP) model with the objective of minimizing the flowspan. We also propose a relaxation of the original MILP in the form of a 2-stage MILP formulation. Next, a scalable approach based on the greedy heuristic is proposed to solve the problem for realistic-size networks. Evaluation results show that the greedy heuristic is suitable for realistic problem sizes where the MILP-based approach is found to be practically infeasible. Furthermore, the impact of wireless requests on the performance of the greedy heuristic is reported.

Bridge of Trust: Cross Domain Authentication for Industrial Internet of Things (IIoT) Blockchain over Transport Layer Security (TLS)

The Industrial Internet of Things (IIoT) holds significant potential for improving efficiency, quality, and flexibility. In decentralized systems, there are no trust-based centralized authentication techniques, which are unsuitable for distributed networks or subnets, as they have a single point of failure. However, in a decentralized system, more emphasis is needed on trust management, which presents significant challenges in ensuring security and trust in industrial devices and applications. To address these issues, industrial blockchain has the potential to make use of trustless and transparent technologies for devices, applications, and systems. By using a distributed ledger, blockchains can track devices and their data exchanges, improving relationships between trading partners, and proving the supply chain. In this paper, we propose a model for cross-domain authentication between the blockchain-based infrastructure and industrial centralized networks outside the blockchain to ensure secure communication in industrial environments. Our model enables cross authentication for different sub-networks with different protocols or authentication methods while maintaining the transparency provided by the blockchain. The core concept is to build a bridge of trust that enables secure communication between different domains in the IIoT ecosystem. Our proposed model enables devices and applications in different domains to establish secure and trusted communication channels through the use of blockchain technology, providing an efficient and secure way to exchange data within the IIoT ecosystem. Our study presents a decentralized cross-domain authentication mechanism for field devices, which includes enhancements to the standard authentication system. To validate the feasibility of our approach, we developed a prototype and assessed its performance in a real-world industrial scenario. By improving the security and efficiency in industrial settings, this mechanism has the potential to inspire this important area.

Optimal Transmission Power and Controller Design for Networked Control Systems Under State-Dependent Markovian Channels

This article considers a codesign problem for industrial networked control systems to ensure both stability and efficiency properties of such systems. This problem is particularly challenging due to the fact that wireless communications in industrial environments are not only subject to shadow fading, but also stochastically correlated with their surrounding environments. This article first introduces a novel state-dependent Markov channel (SD-MC) model that explicitly captures the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">state-dependent features</i> of industrial wireless communication systems by defining the proposed model’s transition probabilities as a function of both environments’ states and transmission power. Under the SD-MC model, sufficient conditions on <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Maximum Allowable Transmission Interval</i> are presented to ensure both <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">asymptotic stability in expectation</i> and <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">almost sure asymptotic stability</i> properties of a nonlinear control system with <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">state-dependent fading channels</i> . Based on these stability conditions, the codesign problem is then formulated as a constrained polynomial optimization problem (CPOP), which can be efficiently solved using semidefinite programming methods for the case of a two-state SD-MC model. The solutions to such a CPOP represent optimal control and power strategies that optimize the average expected joint costs in an infinite time horizon while respecting the stability constraints. For a general SD-MC model, this article further shows that suboptimal solutions can be obtained from linear programming formulations of the considered CPOP. Simulation results are given to illustrate the efficacy of the proposed codesign scheme.

Digital twin oriented architecture for secure and QoS aware intelligent communications in industrial environments

In modern networking industrial environments, characterized by the integration of Operation Technology and Information Technology, there is a strong need to ensure both safety and security of operations and communications. In this regard, IEC 62443 zones and conduits represent powerful high-level abstractions stressing the importance of clearly separating machines in relation to safety requirements and of clearly defining inter-machine communication security requirements. However, their actual implementation is still demanded to human-centric error-prone procedures performed by technicians directly on network elements, without any integrated plant-wide point of view. To overcome these issues, first of all we originally state the need of applying the Digital Twin approach to zones and conduits, making easier the definition and management of inter-machine security requirements. For instance, industrial technicians can specify that communication among two zones should always flows through a ciphered conduit with a given algorithm and key length, at the cost of increased latency. Secondly, we state the need of exploiting an intelligent reasoner to monitor the current state of the environment (represented by asset and network Digital Twins), actively reconfiguring them in case desired requirements are not satisfied. Then, the reasoner allows to enforce requirements while also considering the fulfillment of a proper trade-off between security and performance, e.g., by reducing the ciphering complexity to ensure prompt packet dispatching whenever required. Performance results based on our working prototype demonstrate the feasibility and efficiency of the proposed solution under stringent requirements typical of industrial environments. In particular, in terms of better flexibility we proved that our orchestrator is able to create a new Digital Twin in less than 2.5 s in a typical edge node with a medium load. In addition, proposed routing policies based on our machine learning reasoner led to the satisfaction of well-defined low latency requirements (250 ms) while avoiding packet dropping.

Directive mmWave radio channel modeling in a ship hull

AbstractWireless connectivity has been realized for multiple environments and different frequency bands. However, little research exists about mmWave communication in industrial environments. This paper presents the 60 GHz double-directional radio channel for mmWave communication in a ship hull for Line-of-Sight (LOS) and non-Line-of-Sight (NLOS) conditions. We performed channel measurements using the Terragraph channel sounder at different locations in the ship hull and fitted LOS path loss to a one-slope path loss model. Path loss and root-mean-square delay spread of the LOS path is compared to the reflected path with lowest path loss. NLOS communication via this first-order reflected path is modeled by calculating the path distance and determining the reflection loss. The reflection losses have a considerable contribution to the signal attenuation of the reflected path. The channel models are implemented in an indoor coverage prediction tool, which was extended with a ray launching algorithm and validated by comparison with an analytical electromagnetic solver. The results show that the mmWave radio channel allows high-throughput communication within a ship hull compartment, even when no LOS path between the transmitter and receiver is present.

On Ad Hoc Communication in Industrial Environments

Wireless communication is becoming vital in the industrial environment. New communication technologies, including ad hoc communication, are researched for this application. A thorough understanding regarding the connection characteristics of industrial networks could benefit this trend. In this work it was possible to record the time-variant network topology of such a network utilizing a novel method. Using this method and the generated recordings, novel insights into the behavior of industrial ad hoc networks are presented. The recorded time-variant topology, the tools and method of acquisition, and tools for processing and examination are published. This enables researchers and engineers to check their communication technologies in terms of applicability to the industrial use case and record more network topologies in a wide variety of wireless networking scenarios.

Visible light wireless data communication in industrial environments

Significant implementations and encouraging results have already been achieved using visible light communication (VLC) technology for different applications from indoor to free space optics (FSO) and even underwater communication. The LED light fixtures are about to be used with dual functionality - illumination and fast wireless data communication - and when the technology will become mature enough, the general costs for both will considerably decrease. However, especially due to a complex multipath channel impulse response (CIR) evaluation, there are few research in VLC applied in industrial environments. At the same time, in the non-Line of Sight (NLoS) VLC setup with mobile optical transmitter (oTx) and fixed optical receiver (oRx) considered here, both the path loss and multipath-induced dispersion significantly limits the link performance. In this paper, we investigate the CIR into indoor industrial environments. We take into consideration both Intrinsic Optical Properties in Industrial Environments (IOPIEs) and Apparent Optical Properties (AOPs) in Industrial Environments. The VLC setup complexity such as oTx and oRx position and orientation, the geometry and the nature of the indoor surfaces (diffuse or specular) and appropriate positioning of both oTx and oRx required for a suitable implementation of the VLC. The VLC system proposed is also investigate in this work based on data acquisition, simulation and analysis according the ARX mathematical model.

Using a Large Data Set to Improve Industrial Wireless Communications: Latency, Reliability, and Security

Trealize the Industry 4.0 vision and enable mobile connectivity and flexible deployment in harsh industrial environments, wireless communication is essential. But before wireless communications technology can be widely deployed for critical control applications, first it must be assessed, and that requires a comprehensive characterization of the wireless channel. This can be done by analyzing large amounts of wireless data collected from different industrial environments. In this article, we discuss the possibilities offered by a recently published industrial wireless data set. This data set is more exhaustive than measurements previously reported. We show two cases of how those data have been applied to improve latency performance and to investigate the feasibility of physical-layer security techniques for wireless communication in industrial environments.

Empirical Analysis of the Communication in Industrial Environment Based on G3-Power Line Communication and Influences from Electrical Grid

This paper presents a performance analysis based on a practical approach of narrowband communication through power lines (Power Line Communication—PLC) to the last-mile industrial environment. A kit for developing PLC based applications, in accordance with the G3-PLC standard, was used for the analysis. Experimental tests and results are presented for different scenarios of noise to represent a last-mile industrial environment. The influence of noise insertion in the PLC channel is presented turned on and off a set of inverters and motors, in order to verify the influence of these elements on the performance of the evaluated communication. As a comparative basis, the maximum standard transmission distance of the AS-Interface industrial network standard was used. This standard is widely used in industrial environments for communication between factory floor sensors and actuators. The propose for last-mile to Industry 4.0 can be considered with the results in applications with a large number of sensors. Recommendations regarding the modulation technique and data packet size are presented. Based in this analysis, it can be concluded that the G3-PLC communication standard and its ROBO modulation technique meet the requirements of being used mainly in the last-mile industrial communication, mainly for industrial supervision or control applications where response time is not critical. The last point empirically analyzed concluded that the insertion of the inductive impedance can severely affect the transmission is inserted into the side of the PLC modem transmitter.

Industrial Internet of things over tactile Internet in the context of intelligent manufacturing

With the rapid advance of wireless technologies and its related domains, numerous emerging solutions and applications of industrial wireless systems have been developed, such as industrial Internet of things (2IoT), industrial wireless sensor networks, big data, cloud computing and augmented reality. The present development of communication in industrial environments drives the need for ubiquitous access to distributed resources and services that are connected to things, devices, and systems. However, given the fact that most industrial wireless sensor devices are resource constrained and operate on batteries, the communication overhead is therefore important issues for 2IoT’s design. In the context of intelligent manufacture, all kinds of intelligent equipment (e.g., industrial robots, industrial control system, industrial machine tools and test equipment) supported by wired or wireless networks are widely adopted, and both real-time, delayed signals and system security coexist. In order to efficiently manage these wireless devices in a unified manner, the intelligent manufacture authorities should be able to provide a network infrastructure supporting various 2IoT applications and services. This paper presents an overview of 2IoT’s network infrastructure and describe the information interaction among different devices. Then, a tactile Internet 2IoT architecture is proposed to manage physical devices and provide an interface for information exchange. Finally, the paper is discussed the prominent problems and possible solutions for tactile Internet 2IoT. This work will open a new research direction of 2IoT, and accelerate the implementation of intelligent manufacturing technical architecture.

Wireless Channel Characterization for Indoor Environment in Thermal Power Plant

SUMMARYWireless communications in industrial environments are seriously affected by reliability and performance issues, due to the multipath nature of obstacles within such environments. In order to utilize wireless systems for machine‐to‐machine applications in industrial environments, it is necessary to investigate and model their channel characteristics for optimal design and reliability assessment. However, the wireless channel characterization in such environments has not been sufficiently addressed in the literature within the scope of our knowledge. In this paper, to shed light on the channel modeling for plant applications, we measure and analyze the indoor channel characteristics in a typical thermal power plant. Our results indicate that the channel characterization of the plant environment is specific when compared with the general environments such as houses and offices. The findings in this paper provide a useful guidance to the design of wireless system for the realization of reliable control systems in power plants.

Analysis of WiFi Communication (Data Interchange) for Mobile Robot in Industrial Environment

Wireless network used in office is much cheaper than industrial-type devices. Using of office-type WiFi communication in industrial environment for exchange data between mobile platform (AGV) and base station is the core of this paper. The scope of research is data limitation flow in function of distance between system nodes and usability of office-type (low cost) equipment for establishes stable communication on industrial environment. Paper describes two experiments in two types of production environment. First one was realized in condition where several disturbance sources were active (like metal forming machine-tools, constant energy welding machines, electric overhead crane, high power electric motors, electronic inverters etc. All this machines contaminate radio environment around them and make serious obstacles for WiFi data exchange. Second experiment was executed in assembling hall of automobile production plant in which radio contamination is significantly lower.

Guest Editorial Industrial Wireless Networks: Applications, Challenges, and Future Directions

Yhe papers in this special section focus on industrial wireless networks. With the rapid advance of wireless technologies, numerous emerging solutions and applications of industrial wireless systems have been developed. The present development of communication in industrial environments drives the need for ubiquitous access to distributed resources and services that are connected to things, devices, and systems. Service completions are typically perfected through smart APPS on wireless data delivery, such as WiFi, Bluetooth, ZigBee, and 5G. The occurrence of Internet of Things (IoT) further catalyzes the advent of the wireless era. These papers cover the comprehensive solutions of wireless network developments, industrial applications, and wireless prototype designs.

Pervasive Radio Mapping of Industrial Environments Using a Virtual Reality Approach.

Wireless communications in industrial environments are seriously affected by reliability and performance issues, due to the multipath nature of obstacles within such environments. Special attention needs to be given to planning a wireless industrial network, so as to find the optimum spatial position for each of the nodes within the network, and especially for key nodes such as gateways or cluster heads. The aim of this paper is to present a pervasive radio mapping system which captures (senses) data regarding the radio spectrum, using low-cost wireless sensor nodes. This data is the input of radio mapping algorithms that generate electromagnetic propagation profiles. Such profiles are used for identifying obstacles within the environment and optimum propagation pathways. With the purpose of further optimizing the radio planning process, the authors propose a novel human-network interaction (HNI) paradigm that uses 3D virtual environments in order to display the radio maps in a natural, easy-to-perceive manner. The results of this approach illustrate its added value to the field of radio resource planning of industrial communication systems.

火力発電プラント屋内環境における無線伝搬の特性評価

Wireless communications in industrial environments are seriously affected by reliability and performance issues, due to the multipath nature of obstacles within such environments. In order to utilize wireless systems for M2M applications in industrial environments, it is necessary to investigate and model their channel characteristics for optimal design and reliability assessment. However, the wireless channel characterization in such environments has not been sufficiently addressed in the literature within the scope of our knowledge. In this paper, to shed light on the channel modeling for plant applications, we measure and analyze the indoor channel characteristics in a typical thermal power plant. Our results indicate that the channel characterization of the plant environment is specific when compared with the general environments such as home and office. The findings in this paper provide a useful guidance to the design of wireless system for the realization of reliable control systems in power plants.

Channel Diagnostics for Wireless Sensor Networks in Harsh Industrial Environments

Wireless sensor network communication in industrial environments is compromised by interference, multipath fading, and signal attenuation. In that respect, accurate channel diagnostics is imperative to selecting the adequate countermeasures. This paper presents the lightweight packet error discriminator (LPED) that infers the wireless link condition by distinguishing between errors caused by multipath fading and attenuation, and those inflicted by interfering wideband single-channel communication systems (e.g., IEEE 802.11b/g), based on the differences in their error footprints. The LPED uses forward error correction in a novel context, namely, to determine the symbol error density, which is then fed to a discriminator for error source classification. The classification criteria are derived from an extensive set of error traces collected in three different types of industrial environments, and verified on a newly collected set of error traces. The proposed solution is evaluated both offline and online, in terms of classification accuracy, speed of channel diagnostics, and execution time. The results show that in ≥91% of cases, a single packet is sufficient for a correct channel diagnosis, accelerating link state inference by at least 270%, compared with the relevant state-of-the-art approaches. The execution time of LPED, for the worst case of packet corruption and maximum packet size, is below 30 ms with ≤3% of device memory consumption. Finally, live tests in an industrial environment show that LPED quickly recovers from link outage, by losing up to two packets on average, which is only one packet above the theoretical minimum.

Challenges and conditions for wireless machine-to-machine communications in industrial environments

Wireless solutions are rapidly growing in machine-to-machine communications in industrial environments. These environments provide challenging conditions in terms of radio wave propagation as well as electromagnetic interference. In this article, results from the characterization of radio channel properties are summarized in order to provide some guidelines for the choice of wireless solutions in industrial environments. In conclusion, it is essential to know the sensitivity of industrial processes to time delay in data transfer. Furthermore, it is important to be aware of the radio interference environment and the manner in which different wireless technologies react upon interference. These steps will minimize the risk of unforeseen expensive disturbances in industrial processes.

Scrutinizing Bit- and Symbol-Errors of IEEE 802.15.4 Communication in Industrial Environments

The knowledge of error nature in wireless channels is an essential constituent of efficient communication protocol design. To this end, this paper is the first comprehensive bit- and symbol-level analysis of IEEE 802.15.4 transmission errors in industrial environments. The intention with this paper is to extract the error properties relevant for future improvements of wireless communication reliability and coexistence of radio systems in these harsh conditions. An extensive set of bit-error traces was collected in a variety of scenarios and industrial environments, showing that error behavior is highly dependent on the cause of packet corruption. It is shown that errors inflicted by multipath fading and attenuation exhibit different properties than those imposed by IEEE 802.11 interference. The statistical behavior of these two patterns is concurrently investigated in terms of differences in bit-error distribution, error burst length, channel memory length, and the scale of packet corruption. With these conclusions at hand, abiding to the computational constraints of embedded sensors and the statistical properties of bit-errors, a Reed-Solomon $(15,k)$ block code is chosen to investigate the implications of bit-error nature on practical aspects of channel coding and interleaving. This paper is concluded by a number of findings of high practical relevance, concerning the optimal type, depth, and meaningfulness of interleaving.

Radio-Frequency Electromagnetic Characterization in Factory Infrastructures

In recent years, industrial wireless applications have emerged rapidly. The use of short-range radio communication systems in factories increases the flexibility in industrial processes by reducing the use of cables. However, the technological challenges involved in wireless communication in industrial environments are not trivial; they result in disadvantages with respect to reliability and security because of electromagnetic interference. To gain an understanding of the performance limits of these wireless applications, knowing the characteristics of these environments is essential. In this approach, amplitude probability distribution and rms delay spread measurements have been used to perform electromagnetic site surveys in three factory automation infrastructures.