Industrial Wireless Research Articles

Deterministic Asynchronous Scheduling with Probabilistic Reliability Guarantee in Industrial Wireless Networks

Industrial Wireless Networks (IWNs) play a critical role in industry 4.0 applications. However, industrial control processes require deterministic data delivery with an extremely high reliability, which is challenging in harsh IWN environments. Existing scheduling schemes rely mainly on accurate global synchronization to ensure deterministic transmission, which incurs additional hardware cost and a large communication overhead. To eliminate the synchronization requirements, we propose an asynchronous scheduling model that supports arbitrary time offset between any node pairs. As finding a solution with a given reliability guarantee in this model is a NP-hard problem, we design a probabilistic algorithm based on the Monte Carlo tree search (MCTS) method to generate and verify feasible schedules. The simulation results show that E-MCTS is significantly better in transmission reliability if compared to the classic Monte Carlo tree search algorithm.

POSIMNET-R: An immunologic resilient approach to position routers in Industrial Wireless Sensor Networks

Industry 4.0 has increased the interest in employing Industrial Wireless Sensor Network (IWSN) technologies in industrial automation. The advantages range from ease of installation and maintenance to reduced deployment time and infrastructure costs. However, industrial automation has critical requirements regarding network infrastructure, such as reliability and failure tolerance. Therefore, it is imperative to have an adequate placement of sensor and router nodes, to obtain a network with multiple paths, allowing the data to reach management systems within a reasonable time, even in the event of failures. The placement of router nodes has to consider latency, network lifespan, connectivity, and failure tolerance aspects in a possibly hostile environment, with classified areas and obstacles such as silos, tanks and buildings. We present a new approach, called POSIMNET-R, to place IWSN routing nodes in an industrial configuration, which circumvents forbidden areas and obstacles, based on Artificial Immunological Networks. The resulting network offers low failure rates and path redundancy criteria. The results have shown that POSIMNET-R was capable of providing a reliable network with multiple paths and resilience of the used routers equal to 81.50% in the basic case study and 73.66% in the real case scenario.

Efficient Link Scheduling Based on Estimated Number of Packets in Queue on Industrial Wireless Sensor Networks

The links of low power wireless sensor networks are error prone and the transmission on a wireless link is determined probabilistically by the packet reception rate (PRR) of the link. On the other hand, there is a very strict requirement in the end-to-end reliability and delay of sensor data in industrial wireless sensor networks (IWSNs). The existing approaches to provide the end-to-end reliability in IWSNs is retransmitting the packet when failure occurs. These approaches transmit a packet multiple times in successive time slots to provide the required reliability. These approaches, however, can increase the average delay of packets and the number of packets buffered in a queue. This paper proposes a new scheme to estimate the probabilistic amount of packets, called queue level (QL), in the buffer of each node based on the PRRs of the wireless links. This paper also proposes a QL-based centralized scheduling algorithm to assign time slots efficiently in TDMA-based IWSNs. The proposed scheduling algorithm gives higher priority to the nodes with higher QL. By assigning time slots first to the node with the highest QL, we can reduce the average end-to-end delay of packets and reduce the amount of buffered packets in the queue while satisfying the required end-to-end reliability. The performance of the proposed scheduling algorithm have been evaluated through a simulation using the Cooja simulator and compared with the existing approach. In the simulation on an sample network with the target end-to-end reliability of 99%, all of the flows were shown to guarantee the target reliability in both algorithms: on average, 99.76% in the proposed algorithm and 99.85% in the existing approach. On the other hand, the proposed algorithm showed much better performance than the existing approach in terms of the average end-to-end delay of packets (about 47% less) and the number of maximally buffered packets in the queue of each node (maximally, more than 90% less).

NETWORK EFFECTS AND SWITCHING COSTS IN THE U.S. WIRELESS INDUSTRY

AbstractI estimate a model of dynamic consumer behavior to disentangle switching costs and network effects in the U.S. wireless industry. A detailed panel on market shares and churn rates, disaggregated by demographic consumer types and local markets, allows me to separately identify preference heterogeneity, switching costs, and a localized direct network effect. My switching cost estimates range from USD 47 to USD 178. The average willingness‐to‐pay for a 15 percentage point increase in a carrier's market share is USD 8.50 per month. Finally, I show that ignoring either one of the effects results in substantial errors when simulating counterfactuals.

Multihop Latency Model for Industrial Wireless Sensor Networks Based on Interfering Nodes

Emerging Industry 4.0 applications require ever-increasing amounts of data and new sources of information to more accurately characterize the different processes of a production line. Industrial Internet of Things (IIoT) technologies, and in particular Wireless Sensor Networks (WSNs), allow a large amount of data to be digitized at a low energy cost, thanks to their easy scalability and the creation of meshed networks to cover larger areas. In industry, data acquisition systems must meet certain reliability and robustness requirements, since other systems such as predictive maintenance or the digital twin, which represents a virtual mapping of the system with which to interact without the need to alter the actual installation, may depend on it. Thanks to the IEEE 802.15.4e standard and the use of Time-Slotted Channel Hopping (TSCH) as the medium access mechanism and IPv6 Routing Protocol for Low-Power and Lossy Networks (RPL) as the routing protocol, it is possible to deploy WSNs with high reliability, autonomy, and minimal need for re-configuration. One of the drawbacks of this communication architecture is the low efficiency of its deployment process, during which it may take a long time to synchronize and connect all the devices in a network. This paper proposes an analytical model to characterize the process for the creation of downstream routes in RPL, whose transmission of multi-hop messages can present complications in scenarios with a multitude of interfering nodes and resource allocation based on minimal IPv6 over the TSCH mode of IEEE 802.15.4e (6TiSCH). This type of multi-hop message exchange has a different behaviour than the multicast control messages exchanged during the synchronization phase and the formation of upstream routes, since the number of interfering nodes changes in each retransmission.

Research on H ∞ Preview Control Algorithm for Industrial Wireless Sensor Networks

In order to solve the problem of wireless sensor network control system with network delay and packet loss, a H ∞ preview control algorithm is designed. Firstly, the wireless sensor network model with delay and packet loss is established, and the system error and predictable target signal are introduced to construct the extended error system. Secondly, the state feedback controller with memory is designed. By constructing Lyapunov function and linear matrix inequality, the design method of H ∞ controller and the sufficient conditions for the stability of the system are derived. The optimal H ∞ preview controller algorithm is obtained by solving the LMI optimization problem. Finally, the effectiveness of H ∞ preview controller algorithm is verified by simulation.

Reliability-Constrained Throughput Optimization of Industrial Wireless Sensor Networks With Energy Harvesting Relay

In industrial wireless sensor networks (IWSNs), a lot of energy is wasted in the form of electromagnetic radiations. It can be effectively utilized with energy harvesting (EH), which absorbs part of the energy in the transmission signal but reduces the throughput and reliability of IWSNs. In this article, we study the throughput optimization of IWSNs with EH from the interference radio-frequency (RF) signal considering the reliability constraint of the industrial information transmission. Under the premise of limited energy supply of EH relays, the throughput maximization of IWSNs is formulated as a nonconvex optimization problem. In order to transform the nonconvex problem to a convex optimization problem, the successive convex approximation (SCA) approach is adopted. Furthermore, a power allocation algorithm is designed to maximize the total transmission rate of the network. Simulation results demonstrate that the proposed algorithm can maximize the throughput under the primise of SINR reliability.

Physical Layer Security Analysis of Hybrid MIMO Technology

MIMO is a key enabling technology in the currently emerging 5G systems and future 6G-plus paradigms, such as heterogeneous networks, millimeter-wave networks, vehicular sensor networks, among others. The highly desired properties of MIMO such as its ability to supporting high data rates, improving energy and spectral efficiency, as well as overcoming the effects of shadowing and fading have made it increasingly attractive to the wireless communications industry. Nevertheless, a practical secure MIMO model with the required security levels to guarantee user information protection has still not been realized by the industry. In this work, we analyze and quantify the security performance of hybrid MIMO, which was originally proposed by the preceding work titled “Hybrid MIMO: A New Transmission Method For Simultaneously Achieving Spatial Multiplexing and Diversity Gains in MIMO Systems”. In the proposed method, special signal interference-canceling matrices, which are calculated based on the channel’s variations and randomness between the user and receiver, are superimposed with user data at the physical layer level before being transmitted to the receiver. The conducted performance analysis in this study indicates that the signal interference-canceling matrices provide absolute security (zero information leakage) against both internal and external eavesdroppers. Moreover, the new MIMO technique eliminates the need for any processing at the receiver, where users directly receive their intended signals, consequently lowering complexity and power consumption at the receiver. These are highly desirable properties for the future internet of things (IoT) devices as well as 6G and beyond technologies.

Real-Time Facial Expression Recognition System for Video Big Sensor Data Security Application

Facial video big sensor data (BSD) is the core data of wireless sensor network industry application and technology research. It plays an important role in many industries, such as urban safety management, unmanned driving, senseless attendance, and venue management. The construction of video big sensor data security application and intelligent algorithm model has become a hot and difficult topic in related fields based on facial expression recognition. This paper focused on the experimental analysis of Cohn–Kanade dataset plus (CK+) dataset with frontal pose and great clarity. Firstly, face alignment and the selection of peak image were utilized to preprocess the expression sequence. Then, the output vector from convolution network 1 and β-VAE were connected proportionally and input to support vector machine (SVM) classifier to complete facial expression recognition. The testing accuracy of the proposed model in CK + dataset can reach 99.615%. The number of expression sequences involved in training was 2417, and the number of expression sequences in testing was 519.

Ultra-wideband Flexible Implantable Antenna for Wireless Capsule Endoscopy System with Performance Improvement

The implantable antenna is an important part of the wireless capsule endoscopy (WCE) system to achieve wireless communication. This paper designed an ultra-wideband flexible implantable antenna for wireless capsule endoscopy system. With a very wide bandwidth, the antenna can completely cover the industrial, scientific, and medical frequency bands (ISM, 2.4-2.48 GHz) and Wireless Medical Telemetry Service (WMTS, 1.395-1.4 GHz). The expanded size of the proposed antenna is 18mm× 10mm× 0.1mm. The conformal technology of the antenna has further reduced the space of the system and achieved miniaturization. The capsule antenna in this paper is a compact planar monopole antenna fed by a coplanar waveguide, and it uses a flexible material as a dielectric substrate to achieve the conformal shape of the antenna. U-shaped ground branch (UGB) and a loaded split ring resonator (SRR) structure were used to further improve the antenna performance. Simulation and measurement results were basically the same. On the premise of radiation safety and miniaturization of the antenna, the ultra-wideband operation of the antenna was realized. This antenna design provided reference value for the design and application of the capsule antenna.

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.

An Experimental Framework for 5G Wireless System Integration into Industry 4.0 Applications

The fourth industrial revolution, or Industry 4.0 (I4.0), makes use of wireless technologies together with other industrial Internet-of-Things (IIoT) technologies, cyber–physical systems (CPS), and edge computing to enable the optimization and the faster re-configuration of industrial production processes. As I4.0 deployments are ramping up, the practical integration of 5G wireless systems with existing industrial applications is being explored in both Industry and Academia, in order to find optimized strategies and to develop guidelines oriented towards ensuring the success of the industrial wireless digitalization process. This paper explores the challenges arisen from such integration between industrial systems and 5G wireless, and presents a framework applicable to achieve a structured and successful integration. The paper aims at describing the different aspects of the framework such as the application operational flow and its associated tools, developed based on analytical and experimental applied research methodologies. The applicability of the framework is illustrated by addressing the integration of 5G technology into a specific industrial use case: the control of autonomous mobile robots. The results indicate that 5G technology can be used for reliable fleet management control of autonomous mobile robots in industrial scenarios, and that 5G can support the migration of the on-board path planning intelligence to the edge-cloud.

Recorp: Receiver-oriented Policies for Industrial Wireless Networks

Future Industrial Internet-of-Things (IIoT) systems will require wireless solutions to connect sensors, actuators, and controllers as part of high data rate feedback-control loops over real-time flows. A key challenge in such networks is to provide predictable performance and adaptability in response to link quality variations. We address this challenge by developing RECeiver ORiented Policies (Recorp), which leverages the stability of IIoT workloads by combining offline policy synthesis and run-time adaptation. Compared to schedules that service a single flow in a slot, Recorp policies share slots among multiple flows by assigning a coordinator and a list of flows that may be serviced in the same slot. At run-time, the coordinator will execute one of the flows depending on which flows the coordinator has already received. A salient feature of Recorp is that it provides predictable performance: a policy meets the end-to-end reliability and deadline of flows when the link quality exceeds a user-specified threshold. Experiments show that across IIoT workloads, policies provided a median increase of 50% to 142% in real-time capacity and a median decrease of 27% to 70% in worst-case latency when schedules and policies are configured to meet an end-to-end reliability of 99%.

A Survey on the Application of WirelessHART for Industrial Process Monitoring and Control.

Industrialization has led to a huge demand for a network control system to monitor and control multi-loop processes with high effectiveness. Due to these advancements, new industrial wireless sensor network (IWSN) standards such as ZigBee, WirelessHART, ISA 100.11a wireless, and Wireless network for Industrial Automation-Process Automation (WIA-PA) have begun to emerge based on their wired conventional structure with additional developments. This advancement improved flexibility, scalability, needed fewer cables, reduced the network installation and commissioning time, increased productivity, and reduced maintenance costs compared to wired networks. On the other hand, using IWSNs for process control comes with the critical challenge of handling stochastic network delays, packet drop, and external noises which are capable of degrading the controller performance. Thus, this paper presents a detailed study focusing only on the adoption of WirelessHART in simulations and real-time applications for industrial process monitoring and control with its crucial challenges and design requirements.

Industrial wireless sensor networks with real time data access

This paper targets to transmit industrial data from one sensor node to another sensor node, wirelessly and securely. However as the nodes have Internet access and are typically positioned in an unsupervised context with minimal individual intervention; security and seclusion are the prime challenges in Industrial Wireless Sensor Networks (IWSN). To use IWSN, a user must be able to get real time information straight from the source nodes and this is accomplished by Radio Frequency Identification (RFID). It yields a cost-effective solution of identification problems, but it frequently suffers from diverse safety and privacy difficulties. This paper resolves the issues of RFID systems using Global System for Mobile Communications (GSM) module that generates a One-Time Password (OTP) for accessing the data, and thereby ensures user's privacy and security in Industrial Wireless Sensor Network. Furthermore, eight evaluation criteria have been met by the proposed system surpassing the existing systems.

On the Application of Channel Characteristic-Based Physical Layer Authentication in Industrial Wireless Networks

On the Application of Channel Characteristic-Based Physical Layer Authentication in Industrial Wireless Networks

CBI4.0: A cross-layer approach for big data gathering for active monitoring and maintenance in the manufacturing industry 4.0

Industry 4.0 (I4.0) defines a new paradigm to produce high-quality products at the low cost by reacting quickly and effectively to changing demands in the highly volatile global markets. In Industry 4.0, the adoption of Internet of Things (IoT)-enabled Wireless Sensors (WSs) in the manufacturing processes, such as equipment, machining, assembly, material handling, inspection, etc., generates a huge volume of data known as Industrial Big Data (IBD). However, the reliable and efficient gathering and transmission of this big data from the source sensors to the floor inspection system for the real-time monitoring of unexpected changes in the production and quality control processes is the biggest challenge for Industrial Wireless Sensor Networks (IWSNs). This is because of the harsh nature of the indoor industrial environment that causes high noise, signal fading, multipath effects, heat and electromagnetic interference, which reduces the transmission quality and trigger errors in the IWSNs. Therefore, this paper proposes a novel cross-layer data gathering approach called CBI4.0 for active monitoring and control of manufacturing processes in the Industry 4.0. The key aim of the proposed CBI4.0 scheme is to exploit the multi-channel and multi-radio architecture of the sensor network to guarantee quality of service (QoS) requirements, such as higher data rates, throughput, and low packet loss, corrupted packets, and latency by dynamically switching between different frequency bands in the Multichannel Wireless Sensor Networks (MWSNs). By performing several simulation experiments through EstiNet 9.0 simulator, the performance of the proposed CBI4.0 scheme is compared against existing studies in the automobile Industry 4.0. The experimental outcomes show that the proposed scheme outperforms existing schemes and is suitable for effective control and monitoring of various events in the automobile Industry 4.0.

TSCH and RPL Joining Time Model for Industrial Wireless Sensor Networks.

Wireless sensor networks (WSNs) play a key role in the ecosystem of the Industrial Internet of Things (IIoT) and the definition of today’s Industry 4.0. These WSNs have the ability to sensor large amounts of data, thanks to their easy scalability. WSNs allow the deployment of a large number of self-configuring nodes and the ability to automatically reorganize in case of any change in the topology. This huge sensorization capacity, together with its interoperability with IP-based networks, allows the systems of Industry 4.0 to be equipped with a powerful tool with which to digitalize a huge amount of variables in the different industrial processes. The IEEE 802.15.4e standard, together with the access mechanism to the Time Slotted Channel Hopping medium (TSCH) and the dynamic Routing Protocol for Low-Power and Lossy Networks (RPL), allow deployment of networks with the high levels of robustness and reliability necessary in industrial scenarios. However, these configurations have some disadvantages in the deployment and synchronization phases of the networks, since the time it takes to synchronize the nodes is penalized compared to other solutions in which access to the medium is done randomly and without channel hopping. This article proposes an analytical model to characterize the behavior of this type of network, based on TSCH and RPL during the phases of deployment along with synchronization and connection to the RPL network. Through this model, validated by simulation and real tests, it is possible to parameterize different configurations of a WSN network based on TSCH and RPL.

Development and Validation of an ISA100.11a Simulation Model for Accurate Industrial WSN Planning and Deployment.

During the planning, design, and optimization of an industrial wireless sensor network (IWSN), the proposed solutions need to be validated and evaluated. To reduce the time and expenses, highly accurate simulators can be used for these tasks. This paper presents the development and experimental validation of an ISA100.11a simulation model for industrial wireless sensor networks (IWSN). To achieve high simulation accuracy, the ISA100.11a software stack running on two types of certified devices (i.e., an all-in-one gateway and a field device) is integrated with the ns-3 simulator. The behavior of IWSNs is analyzed in four different types of test scenarios: (1) through simulation using the proposed ISA100.11a simulation model, (2) on an experimental testbed using ISA100.11a certified devices, (3) in a Gateway-in-the-loop Hardware-in-the-loop (HIL) scenario, and (4) in a Node-in-the-loop HIL scenario. Moreover, the scalability of the proposed simulation model is evaluated. Several metrics related to the timing of events and communication statistics are used to evaluate the behavior and performance of the tested IWSNs. The results analysis demonstrates the potential of the proposed model to accurately predict IWSN behavior.

AODR: An Automatic On-Demand Retransmission Scheme for WIA-FA Networks

In Industrial Wireless Sensor Networks (IWSNs), monitoring data generated by field devices are supposed to be delivered to the gateway with high reliability and low latency. However, most of the existing industrial wireless standards are based on IEEE 802.15.4, offering a very limited data rate, which prevents their adoption in critical industrial applications. Based on IEEE 802.11, a recent international standard WIA-FA is proposed to address higher communication requirements in factory automation. In this paper, we study the timeslot allocation for retransmissions in the WIA-FA network. Specifically, we first design a novel superframe to support the Negative ACKnowledgment (NACK)-based retransmission mode in the WIA-FA network, and build a network model which considers the uplink and downlink packet losses simultaneously. Then, we analyze the three major drawbacks of the default NACK-based retransmission scheme in WIA-FA and propose an Automatic On-Demand Retransmission (AODR) scheme. Finally, we give a detailed reliability analysis of the proposed AODR scheme, and prove the relationship between the transmission reliability and critical factors (e.g., the channel condition and the length of the superframe) in the WIA-FA network. Simulation results show that the proposed AODR scheme outperforms existing works in terms of transmission reliability and timeliness for different channel conditions.