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Open Access 2023 | Open Access | Book

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Mixed-Criticality Industrial Wireless Networks

Authors: Xi Jin, Changqing Xia, Chi Xu, Dong Li

Publisher: Springer Nature Singapore

Book Series : Wireless Networks

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About this book

This open access book introduces how to manage important tasks in industrial wireless networks.

Important tasks must be completed on time and with guaranteed quality; that is the consensus reached by system designers and users. However, for too long, important tasks have often been given unnecessary urgency, and people intuitively believe that important tasks should be executed first so that their performance can be guaranteed. Actually, in most cases, their performance can be guaranteed even if they are executed later, and the “early” resources can be utilized for other, more urgent tasks. Therefore, confusing importance with urgency hinders the proper use of system resources. In 2007, mixed criticality was proposed to indicate that a system may contain tasks of various importance levels. Since then, system designers and users have distinguished between importance and urgency.

In the industrial field, due to the harsh environment they operate in, industrial wireless networks’ quality of service (QoS) has always been a bottleneck restricting their applications. Therefore, this book introduces criticality to label important data, which is then allocated more transmission resources, ensuring that important data’s QoS requirements can be met to the extent possible.

To help readers understand how to apply mixed-criticality data to industrial wireless networks, the content is divided into three parts. First, we introduce how to integrate the model of mixed-criticality data into industrial wireless networks. Second, we explain how to analyze the schedulability of mixed-criticality data under existing scheduling algorithms. Third, we present a range of novel scheduling algorithms for mixed-criticality data.

If you want to improve the QoS of industrial wireless networks, this book is for you.

Table of Contents

Frontmatter

Open Access

Chapter 1. Introduction
Abstract
In this chapter, we first provide an overview of industrial wireless networks from the perspectives of industrial communication requirements and classical industrial wireless networks. Then, mixed criticality is introduced, and the role of mixed criticality in industrial wireless networks is also discussed. Last, we present the organization of this book.
Xi Jin, Changqing Xia, Chi Xu, Dong Li

Open Access

Chapter 2. Schedulability Analysis of Mixed-Criticality Data Under Fixed-Priority Scheduling
Abstract
WirelessHART, as a robust and reliable wireless protocol, has been widely-used in industrial systems. Its real-time performance has been extensively studied, but limited to the single-criticality case. Many advanced applications have mixed-criticality communications, where different data flows come with different criticality levels. Hence, in this chapter, we study the real-time mixed-criticality communication based on WirelessHART networks, and present an end-to-end delay analysis method under fixed priority scheduling.
Xi Jin, Changqing Xia, Chi Xu, Dong Li

Open Access

Chapter 3. Schedulability Analysis of Mixed-Criticality Data Under EDF Scheduling
Abstract
In this chapter, to improve the schedulability of high-criticality flows when the network is running, we present a supply/demand bound function analysis method based on earliest deadline first (EDF) scheduling. In addition, our method considers both source routing and graph routing. At the beginning, when the network is in low-criticality mode, source routing is applied. When errors or exceptions occur, the network switches to high-criticality mode, and network routing turns to graph routing to guarantee that critical flows can be scheduled. By estimating the demand bound for the mixed-criticality data model, we can determine the schedulability of industrial wireless networks.
Xi Jin, Changqing Xia, Chi Xu, Dong Li

Open Access

Chapter 4. Mixed-Criticality Scheduling for TDMA Networks
Abstract
To improve the schedulability of mixed-criticality industrial wireless networks, targeted algorithms should be developed. Therefore, in this chapter, we propose a mixed-criticality scheduling algorithm. The algorithm supports centralized optimization and adaptive adjustment. It can improve both the schedulability and flexibility. We conduct extensive simulations, and the results demonstrate that the proposed scheduling algorithm significantly outperforms existing ones.
Xi Jin, Changqing Xia, Chi Xu, Dong Li

Open Access

Chapter 5. Mixed-Criticality Scheduling with Multiple Radio Interfaces
Abstract
In this chapter, we introduce the nodes with multiple radio interfaces (MRI) into mixed-criticality industrial wireless networks. When an error occurs or transmission demand changes, the MRI nodes can switch their transmission mode, changing to a high-criticality configuration to meet the system’s new demand. Hence, we first propose a heterogeneous MRI system model. Based on this model, we propose a Slot Analyzing Algorithm (SAA) that guarantees system schedulability by reallocating slots for each node after replacing conflict nodes with MRI nodes. By considering both system schedulability and cost, SAA also reduces the number of MRI nodes. Then, we propose a Priority Inversion Algorithm (PIA) that improves the schedulability by adjusting slot allocations before replacing conflict nodes with MRI nodes. By reducing the use of MRI nodes, PIA achieves better performance than SAA when the system is in the high-criticality mode.
Xi Jin, Changqing Xia, Chi Xu, Dong Li

Open Access

Chapter 6. Mixed-Criticality Scheduling on 5G New Radio
Abstract
Compared to industrial wired networks, 5G can improve device mobility and reduce the cost of networking. However, the real-time performance and reliability of 5G NR (new radio) still need to be improved to satisfy industrial applications’ requirements. In factories, the main factor that affects the performance of 5G NR is the unstable signal quality caused by high temperatures and metal. Although assigning dedicated resources to all transmissions and retransmissions is an effective method to improve the performance of 5G NR, the unstable signal quality causes the resources required for retransmissions to be uncertain. To address the problem, we introduce the mixed-criticality task model to 5G NR. When high-criticality packets cannot be transmitted, they are allowed to preempt the resources shared with low-criticality packets. The mixed-criticality scheduling problem of 5G NR is NP-hard. We formulate it as an OMT (optimization modulo theories) specification and propose a scheduling algorithm based on bin packing methods to make 5G NR satisfy industrial applications’ requirements. Finally, we conduct extensive evaluations based on an industrial 5G testbed and random test cases. The evaluation results indicate that our algorithm makes communication reliability greater than 99.9% on unlicensed spectrum, and for most test cases, our algorithm is close to optimal solutions.
Xi Jin, Changqing Xia, Chi Xu, Dong Li

Open Access

Chapter 7. Conclusions and Future Directions
Abstract
In this chapter, we summarize the book and provide three potential future directions for mixed-criticality industrial wireless networks.
Xi Jin, Changqing Xia, Chi Xu, Dong Li
Metadata
Title
Mixed-Criticality Industrial Wireless Networks
Authors
Xi Jin
Changqing Xia
Chi Xu
Dong Li
Copyright Year
2023
Publisher
Springer Nature Singapore
Electronic ISBN
978-981-19-8922-3
Print ISBN
978-981-19-8921-6
DOI
https://doi.org/10.1007/978-981-19-8922-3

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