Johan Åkerberg

Future research challenges in wireless sensor and actuator networks targeting industrial automation

A growing trend in the automation industry is to use wireless technologies to reduce cable cost, deployment time, unlocking of stranded information in previously deployed devices, and enabling wireless control applications. Despite a huge research effort in the area of wireless sensor networks (WSNs), there are several issues that have not been addressed properly such that WSNs can be adopted properly in the process automation domain. This article presents the major requirements for typical applications in process automation and we also aim to outline the research direction for industrial wireless sensor networks (IWSNs) in industrial automation. The major issues that need to be addressed are safety, security and availability before industrial wireless sensor networks will be adopted in full scale in process automation.

Efficient Integration of Secure and Safety Critical Industrial Wireless Sensor Networks

Wireless communication has gained more interest in industrial automation due to flexibility, mobility, and cost reduction. Wireless systems, in general, require additional and different engineering and maintenance tasks, for example cryptographic key management. This is an important aspect that needs to be addressed before wireless systems can be deployed and maintained efficiently in the industry.In this paper, we take an holistic approach that addresses safety and security regardless of the underlying media. In our proposed framework we introduce security modules which can be retrofitted to provide end-to-end integrity and authentication measures by utilizing the black channel concept. With the proposed approach, we can extend and provide end-to-end security as well as functional safety using existing automation equipment and standards, such as Profisafe, Profinet IO, and WirelessHART. Furthermore, we improve the WirelessHART standard with periodic and deterministic downlink transmissions to enable efficient usage of wireless actuators, as well as improving the performance of functional safety protocols.

Measurements on an industrial wireless HART network supporting PROFIsafe: A case study

Contrary to the various theoretic publications on safety-critical communication over wireless, this paper will show the actual performance of safety-critical communication in a real plant with all its environmental influences. We used PROFIsafe as a functional safety profile on top of the WirelessHART protocol. Separately these technologies are widely used in industry for safety and wireless communication respectively, but it has never been shown that the combination of them is feasible for safety-critical communication. The main focus of this work is to measure and analyze the round-trip time and the bit error rate of the safety-critical communication in order to identify whether the certification requirements of PROFIsafe holds. We will show that it is technically feasible to run safety-critical data over wireless links. However, long round trip times and high noise in the channel at certain locations in the plant are unacceptable with respect to certification and need further investigations.

Experimental study of UWB-based high precision localization for industrial applications

Recent developments in wireless sensor networks have inspired applications which require high accuracy localization. Impulse radio ultra wide-band technology has a fine time resolution, allowing accurate determination of the time of arrival at the receiver, making it a serious contender for accurate ranging, in comparison to narrow-band technologies. In this paper, we present a UWB based 3D real-time indoor positioning system with 802.15.4a compliant wireless nodes. Results from measurement campaigns reveal that for line-of-sight (LOS) scenarios 11 cm accuracy and 2 cm precision without any postprocessing (i.e. filtering) are possible, hence demonstrating the capability of accurate UWB-based localization using trilateration, resulting in a fast and non-complex algorithm that provides high precision positioning. The proposed system presents an initial step in developing a high precision system for localization in industrial applications.

Reliable and Low Latency Transmission in Industrial Wireless Sensor Networks

The major advantages with Industrial Wireless Sensor Networks (IWSNs) in process automation are cable cost reduction, enhanced flexibility and enabling new emerging applications such as wireless co ...

WirArb: A New MAC Protocol for Time Critical Industrial Wireless Sensor Network Applications

Wireless sensor networks are typically designed for condition monitoring applications and to conserve energy but not for time-critical applications with strict real-time constraints that can be found in the industrial automation and avionics domain. In this paper, we propose a novel medium access control (MAC) protocol defined as wireless arbitration (WirArb) which grants each user channel access based on their different priority levels. The proposed MAC protocol supports multiple users and each user is pre-assigned a specific arbitration frequency which decides the order of channel access. With this mechanism, we can ensure that the user with the highest priority will immediately gain channel access and we can guarantee a deterministic behavior. To evaluate the proposed MAC, we use a discrete-time Markov chain model to mathematically formulate the WirArb protocol. Our results show that the proposed protocol provides high performance to ensure deterministic real-time communication and bandwidth efficiency.

Exploring Security in PROFINET IO

In this paper we show that it is possible to attack and gain control over PROFINET IO nodes and also that this can be done without any of the communicating peers detecting the attack. Analysis of attacks in both shared and packet switched networks show that the attacker can control the process data and thus the state of the machines connected to the I/O modules. As the security risks are increasing in automation with the level of vertical and horizontal integration, the concept of security modules is proposed towards a method to retrofit security in PROFINET IO. The concept of security modules can be applied without changing anything in the underlying transmission system and is extendable if and when new security threats are identified.

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.

REALFLOW: Reliable Real-Time Flooding-Based Routing Protocol for Industrial Wireless Sensor Networks

Wireless technologies have been increasingly applied in industrial automation systems due to flexible installation, mobility, and cost reduction. Unlike traditional wireless sensor networks (WSNs), industrial wireless sensor networks (IWSNs), when expanding from wireless monitoring to wireless control, have more stringent requirements on reliability, real-time performance, and robustness in a number of industrial applications. Successive transmission failures or deadline misses in these applications may severely degrade the control quality and result in serious economic losses and safety problems. Therefore, when deploying IWSNs in harsh industrial environments, to achieve reliable and deterministic end-to-end transmissions is critically important. In this paper, we explain the primary challenges of designing appropriate routing protocols and present a reliable real-time flooding-based routing protocol for IWSNs (REALFLOW). Instead of traditional routing tables, related node lists are generated in a simple distributed manner, serving for packet forwarding. A controlled flooding mechanism is applied to improve both reliability and real-time performance. A seamless transition in the event of topology change can be achieved by REALFLOW. Performance evaluations via simulations verify that significant improvements of reliability, real-time performance, and network recovery time can be achieved by REALFLOW, compared with traditional routing protocols.

Adaptive forward error correction for best effort Wireless Sensor Networks

In this work we propose an Adaptive Forward Error Correction (AFEC) algorithm for best effort Wireless Sensor Networks. The switching model is described in terms of a finite-state Markov model and it is based on the channel behavior, observed via Packet Delivery Ratio in the recent past. We compare the performance of AFEC with static FEC, as well as uncoded transmissions. The results demonstrate a gain in PDR achieved by introducing FEC coding in uncoded IEEE 802.15.4 transmissions, as well as the advantages over static FEC schemes, namely increased throughput and reduced energy consumption. The proposed solution is IEEE 802.15.4-compliant and requires no additional feedback channels.