WirelessHART Network Research Articles

Online Distributed Schedule Randomization to Mitigate Timing Attacks in Industrial Control Systems

Industrial control systems (ICSs) consist of a large number of control applications that are associated with periodic real-time flows with hard deadlines. To facilitate large-scale integration, remote control, and co-ordination, wireless sensor and actuator networks form the main communication framework in most ICSs. Among the existing wireless sensor and actuator network protocols, WirelessHART is the most suitable protocol for real-time applications in ICSs. The communications in a WirelessHART network are time-division multiple access based. To satisfy the hard deadlines of the real-time flows, the schedule in a WirelessHART network is pre-computed. The same schedule is repeated over every hyperperiod (i.e., lowest common multiple of the periods of the flows). However, a malicious attacker can exploit the repetitive behavior of the flow schedules to launch timing attacks (e.g., selective jamming attacks). To mitigate timing attacks, we propose an online distributed schedule randomization strategy that randomizes the time-slots in the schedules at each network device without violating the flow deadlines, while ensuring the closed-loop control stability. To increase the extent of randomization in the schedules further, and to reduce the energy consumption of the system, we incorporate a period adaptation strategy that adjusts the transmission periods of the flows depending on the stability of the control loops at runtime. We use Kullback-Leibler divergence and prediction probability of slots as two metrics to evaluate the performance of our proposed strategy. We compare our strategy with an offline centralized schedule randomization strategy. Experimental results show that the schedules generated by our strategy are 10% to 15% more diverse and 5% to 10% less predictable on average compared to the offline strategy when the number of base schedules and keys vary between 4 and 6 and 12 and 32, respectively, under all slot utilization (number of occupied slots in a hyperperiod). On incorporating period adaptation, the divergence in the schedules reduceat each period increase with 46% less power consumption on average.

Revealing Smart Selective Jamming Attacks in WirelessHART Networks

As a leading industrial wireless standard, WirelessHART has been widely implemented to build wireless sensor-actuator networks (WSANs) in industrial facilities, such as oil refineries, chemical plants, and factories. For instance, 54,835 WSANs that implement the WirelessHART standard have been deployed globally by Emerson process management, a WirelessHART network supplier, to support process automation. While the existing research to improve industrial WSANs focuses mainly on enhancing network performance, the security aspects have not been given enough attention. We have identified a new threat to WirelessHART networks, namely smart selective jamming attacks, where the attacker first cracks the channel usage, routes, and parameter configuration of the victim network and then jams the transmissions of interest on their specific communication channels in their specific time slots, which makes the attacks energy efficient and hardly detectable. In this paper, we present this severe, stealthy threat by demonstrating the step-by-step attack process on a 50-node network that runs a publicly accessible WirelessHART implementation. Experimental results show that the smart selective jamming attacks significantly reduce the network reliability without triggering network updates.

Towards Reliability and Safety Improvement of Measurement and Control Processes on Ships: Implementation of Wireless Hart Protocol

Abstract Measurement and control systems in maritime engineering applications are quite similar to those in shore based engineering applications except for some unique features which differentiate between each of them. These features are either related to the specific nature and purpose of the maritime application (Various types of commercial ships, oil/gas rigs and others) or linked to the harsh environmental conditions such as salinity, corrosion and vibration which usually exist in higher levels than shore based applications. Accordingly and due to such a specific nature of maritime engineering applications, more requirements should be considered to ensure reliability and stability for measurement and control process avoiding any negative effects that might be associated with such a unique engineering environment. As was discussed in (Abotaleb, 2021), smart transmitters based on hybrid analogue-digital (HART) and digital (Foundation Fieldbus and Profibus PA) communication protocols with additional diagnostic information, they might be a possible wired alternative for analogue transmitters (mostly based on 4-20 mA analogue standard). Similarly, wireless HART protocol can be an alternative for 4-20 mA analogue transmitters. This article will discuss the possibility of replacing classical 4-20 mA analogue transmitters with wireless HART smart transmitters on commercial ships as an example for maritime engineering application. The first section of the discussion will include a theoretical background for the basic principles of wireless HART protocol among other wireless technologies used in industrial automation. The second section of the article will discuss the possibility of utilising wireless HART protocol in the most common measurement and control systems on any commercial ship in order to discover the degree to which wireless HART can be fully or partially integrated with maritime engineering applications. Afterwards, better realization for such a concept will be rendered by an analytical planning case study conducted for tank level measurement system on different types of commercial ships. Based on both the theoretical and the analytical sections, the experimental section will manifest the importance of some of the necessary key elements to implement a reliable wireless HART network. These key elements are RSSI levels, supply voltage stability and the capability of wireless HART adapters to integrate between wired HART protocol and wireless HART network.

Reliable Fault Tolerant-Based Multipath Routing Model for Industrial Wireless Control Systems

Communication in industrial wireless networks necessitates reliability and precision. Besides, the existence of interference or traffic in the network must not affect the estimated network properties. Therefore, data packets have to be sent within a certain time frame and over a reliable connection. However, the working scenarios and the characteristics of the network itself make it vulnerable to node or link faults, which impact the transmission reliability and overall performance. This article aims to introduce a developed multipath routing model, which leads to cost-effective planning, low latency and high reliability of industrial wireless mesh networks, such as the WirelessHART networks. The multipath routing model has three primary paths, and each path has a backup node. The backup node stores the data transmitted by the parent node to grant communication continuity when primary nodes fail. The multipath routing model is developed based on optimal network planning and deployment algorithm. Simulations were conducted on a WirelessHART simulator using Network Simulator (NS2). The performance of the developed model is compared with the state-of-the-art. The obtained results reveal a significant reduction in the average network latency, low power consumption, better improvement in expected network lifetime, and enhanced packet delivery ratio which improve network reliability.

A Distributed Real-time Scheduling System for Industrial Wireless Networks

The concept of Industry 4.0 introduces the unification of industrial Internet-of-Things (IoT), cyber physical systems, and data-driven business modeling to improve production efficiency of the factories. To ensure high production efficiency, Industry 4.0 requires industrial IoT to be adaptable, scalable, real-time, and reliable. Recent successful industrial wireless standards such as WirelessHART appeared as a feasible approach for such industrial IoT. For reliable and real-time communication in highly unreliable environments, they adopt a high degree of redundancy. While a high degree of redundancy is crucial to real-time control, it causes a huge waste of energy, bandwidth, and time under a centralized approach and are therefore less suitable for scalability and handling network dynamics. To address these challenges, we propose DistributedHART—a distributed real-time scheduling system for WirelessHART networks. The essence of our approach is to adopt local (node-level) scheduling through a time window allocation among the nodes that allows each node to schedule its transmissions using a real-time scheduling policy locally and online. DistributedHART obviates the need of creating and disseminating a central global schedule in our approach, thereby significantly reducing resource usage and enhancing the scalability. To our knowledge, it is the first distributed real-time multi-channel scheduler for WirelessHART. We have implemented DistributedHART and experimented on a 130-node testbed. Our testbed experiments as well as simulations show at least 85% less energy consumption in DistributedHART compared to existing centralized approach while ensuring similar schedulability.

Packet Delivery Maximization Using Deep Reinforcement Learning-Based Transmission Scheduling for Industrial Cognitive Radio Systems

The performance of data aggregation in industrial wireless communications can be degraded by environmental interference on Industrial Scientific Medical (ISM) channels. In this paper, cognitive radio (CR) was applied to enable devices to share primary channels with the aim of enhancing the transmission performance of the WirelessHART network. We considered a linear convergecast system, where the packets generated at each device were routed to the gateway (GW) through the aid of neighboring devices. The solar-powered cognitive access points (CAPs) were deployed to improve the network performance by opportunistically allocating the primary channels to the devices for data transmissions. Firstly, we formulate the scheduling problem of long-term throughput maximization as a framework of a Markov decision process with the constraints of the minimum delay, the number of required ISM channels, and the harvested energy at the CAPs. Then, we propose a deep reinforcement learning-based scheduling scheme to optimally assign multiple ISM and primary channels to the field devices in each superframe. The simulation results confirmed the superiority of the proposed scheme compared to existing methods.

A Minimized Buffered Link Scheduling Algorithm for WirelessHART Networks Based on Graph Route

WirelessHART network is an emerging wireless sensor network technology, famous for simplicity, safety, and reliability. WirelessHART network uses Time Division Media Access (TDMA) and Frequency Hopping Spread Spectrum (FHSS) access mechanism to avoid collisions and mitigate interference from other wireless networks. Many formulations of the link scheduling problem have been proven to be NP-complete, which is about how to assign slots and channels to links. In this paper, we propose a minimized buffered link scheduling algorithm for WirelessHART networks based on graph route (LBLSGR), which utilizes edge coloring to scheduling time slots according to the resource demand of nodes. We supply more communication resource to the nodes located nearer to the gateway, because of frequent packet forwarding. Utilizing this algorithm, the WirelessHART networks can make the average network delay least, the average network power assumption lower, and the packet buffers minimized. At last, the validity of our algorithm is proved and the test result is provided.

Quality Analysis of Data Transferring Through the Process of Modeling WirelessHART Network

The topology of WirelessHART network is changeable since a number of dynamic devices change, and all that requires a reorganization of the network, as well as finding new ways of routing data. Devices can fall out of the network due to destruction, failure, reduction or loss of electricity. On the other hand, it is possible to “refresh” the network with new devices and thus completely change the topology of the newly created network. This research analize the quality of data transferring in a WirelessHART network using two network topologies: Extended star network and Mesh network. The aim of this paper is to determine which network topology provides better quality of data transferring in a WirelessHART network on the basis of signal latency and Received Signal Strength Indicator (RSSI). To achieve this, experiments are performed using the equipment by the manufacturer Emerson Process Management: Gateway 1420, TT 648 and PT 3051 for the implementation of the network, as well as software tools for configuration, planning and management of wireless industrial networks, AMS Wireless SNAP-ON and AMS Intelligent Device Manager. The research results show several advantages of applying Mesh topology in a WirelessHART network: it is almost impossible to interrupt communication between devices in the network; there does not have to be optical visibility between the network devices; ease of installation and deinstallation; low application cost compared to Extended star network.

A schedule randomization policy to mitigate timing attacks in WirelessHART networks

Industrial control systems consist of large-scale wireless sensor-actuator networks (WSAN) that control the physical plant. The communications between the sensors and the actuators need to be reliable and guaranteed within strict deadlines for safe operation of all the system components in industrial setups. WirelessHART is the most suitable and widely adopted WSAN standard that serves as the medium of communication in industries. To satisfy deadlines of real-time flows in WirelessHART networks, the centralized network manager decides the communication schedule during network initialization. The same schedule repeats every hyperperiod. The repetitive nature of the communication slots over every hyperperiod makes the system vulnerable to timing attacks which can eventually disrupt the safety of the system. To mitigate such attacks, we propose SlotSwapper, a moving target defense mechanism that randomizes the communication slots over a hyperperiod schedule without violating the feasibility constraints of real-time flows in WirelessHART networks. We show that SlotSwapper is optimal for single-channel WirelessHART network with real-time harmonic flows. We extensively evaluated our algorithm with $$\varvec{4800}$$ flow sets over $$\varvec{100}$$ Tmote sky motes in Cooja simulator. We use Prediction Probability of slots of a schedule to measure the security provided by SlotSwapper. We use Kullback–Leibler divergence to measure the divergence of our solution w.r.t. a truly random solution.

Joint Scheduling and Channel Allocation for Kalman Filtering Over Multihop WirelessHART Networks

Remote state estimation over a wireless network is of significant importance in many industrial applications, such as condition monitoring. In these cases, sensors deliver their data to remote estimators through wireless channels, which makes communication reliability a core issue. In this article, we propose an error-aware design to carry out network scheduling and channel allocation according to estimation error covariance and channel quality, with the aim of minimizing the total estimation error covariance. We develop multidimensional conflict graphs to model the interference and conflicts, and on this basis, a two-phase heuristic algorithm is further proposed to adaptively assign slots and channels at each superframe. Theoretical analysis and extensive simulations are given to show the effectiveness of our error-aware design in preventing the estimation error covariance from diverging, and hence able to improve the accuracy of remote estimation and monitoring.

SlotSwapper

Industrial process control systems are time-critical systems where reliable communications between sensors and actuators need to be guaranteed within strict deadlines to maintain safe operation of all the components of the system. WirelessHART is the most widely adopted standard which serves as the medium of communication in industrial setups due to its support for Time Division Multiple Access (TDMA) based communication, multiple channels, channel hopping, centralized architecture, redundant routes and avoidance of spatial re-use of channels. However, the communication schedule in WirelessHART network is decided by a centralized network manager at the time of network initialization and the same communication schedule repeats every hyper-period. Due to predictability in the time slots of the communication schedule, these systems are vulnerable to timing attacks which eventually can disrupt the safety of the system. In this work, we present a moving target defense mechanism, the SlotSwapper, which uses schedule randomization techniques to randomize the time slots over a hyper-period schedule, while still preserving all the feasibility constraints of a real-time WirelessHART network and makes the schedule uncertain every hyper-period. We tested the feasibility of the generated schedules on random topologies with 100 simulated motes in Cooja simulator. We use schedule entropy to measure the confidentiality of our algorithm in terms of randomness in the time slots of the generated schedules.

Adaptive Channel Map for Time Slotted Channel Hopping Industrial Wireless Networks

The use of wireless networks in industrial environments is a reality today because of its advantages, but with the use of such networks, the problem of coexistence becomes inevitable. This paper presents a system to deal with the problems brought on by the networks coexistence, and thus avoid a reduction in the robustness of the network in which this issue has been accomplished. An adaptive channel mapping system is proposed in industrial wireless networks, where the affected channels are removed from the channel map used. A case study of the adaptive channel mapping system in a WirelessHART network is performed.

High Reliability, Low Latency and Cost Effective Network Planning for Industrial Wireless Mesh Networks

In this paper, we study high reliability, low latency and cost effective network planning for industrial wireless mesh networks. Based on the requirements of routing reliability, minimum end-to-end delay and reduced deployment cost in wireless mesh networks, such as WirelessHART network, we propose three network planning approaches following the principles of the shortest hops, the least routers and balance of the shortest hops and the least routers, respectively. We then implement the proposed algorithms respectively to generate the network deployment for a given factory layout. Simulation results show that there exists a performance trade-off between these three algorithms. The proposed algorithms have also been implemented and validated in an NS-2 WirelessHART network simulator.

Stabilization of Non-Linear Networked Control Systems Closed Over a Lossy WirelessHART Network

This letter studies the stabilization of non-linear networked control systems (NCSs) where the information between plant and controller is sent over a lossy wireless multi-hop network under a carrier-sense multiple access with collision avoidance (CSMA-CA) scheme. We present a hybrid model for the overall NCS that captures time-varying transmission instants, both inter-and at-transmission behavior, packet dropouts, field device dynamics, and CSMA-CA scheduling. We then use this model to provide sufficient conditions in terms of the intensity of transmission that ensure closed-loop $ \mathcal {L}_{p}$ stability-in-expectation. In doing so, we exploit the mathematical structure of our NCS model to improve previous results in the literature.

Implementation of flow control over WirelessHART sensor network using WirelessHART adaptors

<p>Despite the advantages of the industrial wireless standards such as WirelessHART, ISA100.11a and Wireless Networks for Industrial Automation-Process Automation (WIA-PA), their application still faces a lot of challenges especially when it comes to interfacing with the real plant. This is due to lack of adequate infrastructures such as interfacing circuitry to establish communication between the WirelessHART nodes and the actuators and sensors. Therefore, this paper presents the application of locally developed WirelessHART adaptors for flow process control. The adaptors serve as an interface between the WirelessHART network and the sensor and actuator of the plant. Experimental results of the controllers compared showed that wireless control is possible through the use of the adaptors.</p>

Toward Cloud-Assisted Industrial IoT Platform for Large-Scale Continuous Condition Monitoring

Process industries cover a wide set of industries, in which the processes are controlled by a combination of distributed control systems (DCSs) and programmable logic controllers (PLCs). These control systems utilize various measurements such as pressure, flow, and temperature to determine the state of the process and then use field devices such as valves and other actuating devices to manipulate the process. Since there are many different types of field devices and since each device is calibrated to its specific installation, when monitoring devices, it is important to be able to transfer not only the device measurement and diagnostics but also characteristics about the device and the process in which it is installed. The current monitoring architecture, however, creates challenges for continuous monitoring and analysis of diagnostic data. In this paper, we present the design of an Industrial Internet-of-Things (IIoT) system for supporting large-scale and continuous device condition monitoring and analysis in process control systems. The system design seamlessly integrates existing infrastructure [e.g., highway addressable remote transducer (HART) and WirelessHART networks, and DeltaV DCS] and newly developed hardware/software components (e.g., one-way data diode and IoT cellular architecture) together for control network data collection and streaming of the collected device diagnostic parameters to a private cloud to perform streaming data analytics designed for fault identification and prediction. A prototype system has been developed and supported by Emerson Automation Solutions and deployed in the field for design validation and long-term performance evaluation. To the best of our knowledge, this is the first ever publicly reported effort on IoT system design for process automation applications. The design can be readily extended for condition monitoring and analysis of many other industrial facilities and processes.

Supervisory Control for Wireless Networked Power Converters in Residential Applications

This paper presents a methodology to design and utilize a supervisory controller for networked power converters in residential applications. Wireless networks have been interfaced to multiple power factor correction (PFC) converters which are proposed to support reactive power. Unregulated reactive power support from PFC converters could cause reactive power deficiency and instability. Therefore, a supervisory controller is necessary to govern the operation of PFC converters. WiFi and WirelessHART networks have been used to implement the supervisory controller. Different nodes of the power network are connected by wireless communication links to the supervisory controller. Asynchronous communication links latency and uncertain states affect the control and response of the PFC converters. To overcome these issues, the supervisory controller design method has been proposed based on the system identification and the Ziegler-Nichols rule. The proposed supervisory controller has been validated by using a hardware-in-the-loop (HIL) test bed. The HIL testbed consisted of an OP4510 simulator, a server computer, Texas Instrument-Digital Signal Controllers (TI-DSCs), WiFi and WirelessHART modules. Experimental results show that the proposed supervisory controller can help to support and govern reactive power flow in a residential power network. The proposed method of controller design will be useful for different small-scale power and wireless network integration.

Joint Scheduling and Channel Allocation for End-to-End Delay Minimization in Industrial WirelessHART Networks

WirelessHART is one of the most widely used communication standards in industrial wireless networks. In order to meet the stringent real-time requirements in industrial applications, WirelessHART incorporates many designs including the time slotted channel hopping mechanism that enables dynamic time scheduling and channel allocation. In this paper, we study the problem of joint transmission scheduling and channel allocation aiming to minimize the end-to-end delay of multiple flows in multihop WirelessHART networks. We propose a new network model based on a multidimensional scheduling space spanned by flow-link-channel-slot tuples. A multidimensional conflict graph is then established to depict the conflict relationships among the tuples. Based on this, the original delay minimization problem is formulated as an integer program, which however is difficult to solve due to its significantly large scale. To this end, we develop an iterative hop-wise scheduling algorithm by transforming the original problem into a series of maximum weighted independent set problems. We derive theoretical analysis on the schedulability and the performance bound of the proposed algorithm. In addition, we show that our results can be easily extended to accommodate more general scenarios. Finally, extensive simulation results are provided to demonstrate the effectiveness of the algorithm.

Codesign of controller, routing and scheduling in WirelessHART networked control systems

SummaryIn this paper, we provide a novel methodology to co‐design controller, scheduling and routing in a wireless control network compliant with the WirelessHART protocol. We both provide a modeling framework and derive a novel suboptimal solution to the linear‐quadratic regulator problem for a class of systems that extends Markov jump linear system considering both continuous and discrete inputs. To allow that, our results can be directly implemented in a real WirelessHART network, we setup a receding horizon optimization problem that takes into account the constraint for compliance with WirelessHART and validate our solution on a batch reactor control loop.

Design optimization of WirelessHART networks in Cyber-Physical Systems

Abstract Recently, more and more factories begin to employ wireless mesh networks for process control. The high dynamics of wireless mesh network leads to a tight interaction between control performance and communication reliability. As a result, these wireless Cyber-Physical Systems need a holistic co-design approach to integrate the cyber space and physical space. In this paper, we establish a regulation of co-design strategies for wireless Cyber-Physical Systems. We also propose a heuristic algorithm to seek the feasible values of co-design parameters in the huge design space. A testbed is deployed for exploration and evaluation in industrial environment. The results show that our proposed co-design method provides an approach to enhance communication reliability and control performance even under harsh industrial environment.