Isochronous Wireless Network for Real-time Communication in Industrial Automation (eBook)

Dr.-Ing. Henning Trsek studied Electrical Engineering and Information Technology at the OWL University of Applied Sciences, Lemgo, Halmstad University, Sweden, and Aalborg University, Denmark. Afterwards he was employed at the Institute Industrial IT (inIT) with the responsibilities of a research group leader. At the same time he obtained his Dr.-Ing. from the Otto-von-Guericke-University Magdeburg. His research interests are in the area of Smart Factories, Industrie 4.0 and Industrial Security. Currently, he is employed at rt-solutions.de as Senior Consultant and responsible for the Industrial Security group.

Preface 7
Zusammenfassung 7
Abstract 9
Acknowledgement 10
Contents 11
List of Abbreviations 15
1 Introduction 18
1.1 Application Scenario 18
1.2 Problem Exposition 25
1.3 Solution Approach 27
1.4 Structure of the Thesis 29
2 Related Work and Background 30
2.1 Communication in Industrial Automation 30
2.1.1 Real-time Ethernet 30
2.1.2 Engineering Aspects and Flexibility 35
2.2 Industrial Wireless Communication 35
2.2.1 Systems Based on IEEE 802.15.1 36
2.2.2 Systems Based on IEEE 802.15.4 38
2.3 IEEE 802.11 40
2.3.1 Physical Layer 40
2.3.2 Medium Access Control 41
2.3.3 Admission Control and Scheduling 44
2.3.4 Relevant Amendments 45
2.3.5 Industrial Extensions 47
2.3.6 Existing Limitations of IEEE 802.11 47
2.4 Wireless Network Topologies 49
2.5 Analysis and Classification 50
3 Industrial Environment Characterisation 52
3.1 Industrial Traffic Characteristics and Requirements 52
3.1.1 Quality-of-Service Requirements for Common Multimedia Services 53
3.1.2 Analysis and Measurement Methodology 54
3.1.3 Manufacturing System for Terminal Blocks 54
3.1.4 Robot Cell 59
3.2 Industrial Wireless Channel 61
3.2.1 Weaknesses of Existing Channel Characterisation Approaches 62
3.2.2 Approach to Wireless Channel Characterisation 63
3.2.3 Channel Characterisation 65
4 Isochronous Wireless Network for Industrial Automation 69
4.1 System Model 69
4.1.1 Network Model 69
4.1.2 QoS Parameter for Control Applications 71
4.1.3 Fault Model 75
4.2 Isochronous Wireless Network 76
4.2.1 Deterministic Medium Access Control 77
4.2.2 Resource Allocation 78
4.2.3 Global Time Base 79
4.3 Integration Aspects 80
4.3.1 Mapping Concepts 80
4.3.2 Hybrid System Implications 81
5 Deterministic Medium Access Control 84
5.1 Coordinated Medium Access Control 84
5.1.1 Related Work 84
5.1.2 Protocol Description using UML 87
5.2 Isochronous Medium Access Control 87
5.2.1 Network Topology 88
5.2.2 Coordinated Channel Access 89
5.2.3 Schedule Distribution and Restricted Phase 92
5.3 Frame Error Recovery 93
5.3.1 Recovery Phase 93
5.3.2 Beacon Recovery 94
5.4 Analysis of the Isochronous MAC 95
5.4.1 Upper Bounds of the IsoMAC Approach 96
5.4.2 Efficiency of IsoMAC 99
5.4.3 Temporal Characteristics 101
5.5 Concluding Remarks 105
6 Resource Allocation 106
6.1 Admission Control and Scheduling in TDMA-based Wireless Networks 106
6.1.1 Related Work 106
6.1.2 Industrial Traffic Types 108
6.2 Admission Control 109
6.2.1 Retransmission Behaviour in Industrial Environments 110
6.2.2 Cross-layer Traffic Inspection 112
6.2.3 Resource Reservation and Admission Control 113
6.3 Scheduler 114
6.3.1 Scheduling and Admission Control of Periodic Flows 114
6.3.2 Scheduling and Admission Control of Aperiodic Flows 115
6.4 Dynamic Scheduling of Retransmissions 116
6.4.1 Application Layer Considerations 117
6.4.2 Adaptive Retransmission Policies 118
6.4.3 Analysis of the Dynamic Resource Allocation 119
7 Provision of a Global Time Base 121
7.1 Clock Synchronization in Hybrid Networks 121
7.1.1 Problems and Requirements 121
7.1.2 Related Work 122
7.1.3 Precision Time Protocol 124
7.2 Wireless Synchronization Concept 125
7.2.1 Precision Time Protocol over Wireless 127
7.2.2 Clock Synchronization Using Beacon Frames 128
7.2.3 Path-delay Asymmetry Compensation 129
7.3 Challenges for Time Stamping 130
7.3.1 Packet Reception Time 130
7.3.2 Interrupt Notification 131
7.3.3 Interrupt Handling Delay 131
7.3.4 Timestamping Delay 132
7.4 Accuracy and Precision Analysis 133
7.4.1 Testbed Setup 133
7.4.2 Bandwidth Utilization 134
7.4.3 Accuracy and Precision 135
7.5 Concluding Remarks 138
8 Evaluation 139
8.1 Overview and Structure 139
8.2 Prototypical Implementation 141
8.2.1 Implementation Architecture 141
8.2.2 IWN Access Point 143
8.2.3 IWN Node 144
8.3 Simulation Modeling 144
8.3.1 Conceptual Simulation Model 144
8.3.2 Wireless Channel Model 146
8.3.3 Model Validation 150
8.4 Case Study 1: Reconfigurable Manufacturing 155
8.4.1 Approach and Implementation of the Experiments 155
8.4.2 Results of the First Experiment 157
8.4.3 Results of the Second Experiment 158
8.4.4 Summary of Case Study 1 159
8.5 Case Study 2: Wind Energy Automation 160
8.5.1 Approach and Implementation of the Experiments 160
8.5.2 Results of the First Experiment 162
8.5.3 Results of the Second Experiment 164
8.5.4 Summary of Case Study 2 167
8.6 Concluding remarks 167
9 Conclusion and Future Research Directions 168
9.1 Conclusion 168
9.2 Future Research Directions 169
References 171