SPRINGER BRIEFS IN COMPUTER SCIENCE Feng Xia Azizur Rahim MAC Protocols for Cyber-Physical Systems 123 SpringerBriefs in Computer Science Series editors Stan Zdonik, Brown University, Providence, USA Shashi Shekhar, University of Minnesota, Minneapolis, USA Jonathan Katz, University of Maryland, College Park, USA Xindong Wu, University of Vermont, Burlington, USA Lakhmi C. Jain, University of South Australia, Adelaide, Australia David Padua, University of Illinois Urbana-Champaign, Urbana, USA Xuemin (Sherman) Shen, University of Waterloo, Waterloo, Canada Borko Furht, Florida Atlantic University, Boca Raton, USA V.S. Subrahmanian, University of Maryland, College Park, USA Martial Hebert, Carnegie Mellon University, Pittsburgh, USA Katsushi Ikeuchi, University of Tokyo, Tokyo, Japan Bruno Siciliano, Università di Napoli Federico II, Napoli, Italy Sushil Jajodia, George Mason University, Fairfax, USA Newton Lee, Newton Lee Laboratories, LLC, Tujunga, USA More information about this series at http://www.springer.com/series/10028 Feng Xia Azizur Rahim (cid:129) MAC Protocols for Cyber-Physical Systems 123 FengXia Azizur Rahim DalianUniversity ofTechnology DalianUniversity ofTechnology Dalian Dalian China China ISSN 2191-5768 ISSN 2191-5776 (electronic) SpringerBriefs inComputer Science ISBN978-3-662-46360-4 ISBN978-3-662-46361-1 (eBook) DOI 10.1007/978-3-662-46361-1 LibraryofCongressControlNumber:2015940979 SpringerHeidelbergNewYorkDordrechtLondon ©TheAuthor(s)2015 Thisworkissubjecttocopyright.AllrightsarereservedbythePublisher,whetherthewholeorpart of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission orinformationstorageandretrieval,electronicadaptation,computersoftware,orbysimilarordissimilar methodologynowknownorhereafterdeveloped. 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Printedonacid-freepaper Springer-VerlagGmbHBerlinHeidelbergispartofSpringerScience+BusinessMedia (www.springer.com) Preface Cyber-Physical Systems (CPS) is one of the most promising directions in the field ofinformationandcommunicationtechnologies.Ithasattractedintensiveattention andparticipationfrombothindustryandfromacademiainthepastfewyears.CPS are integrations of computation, networking, and physical dynamics, in which embeddeddevicesarenetworkedtosense,monitor,andcontrolthephysicalworld. This radical transformation from stand-alone devices to networked systems facili- tatesvariousinnovativeapplications,notonlyonalargescalebutalsoforpersonal and micro-level use. To fully explore the potential of CPS, however, various applications including Wireless Body Area Networks (WBANs) require high Quality of Services (QoS) in terms of timeliness, reliability, energy efficiency, and othermetrics.MediumAccessControl(MAC)layerplaysacriticalroleinmeeting these requirements. For instance, reliability can be achieved with enhanced scheduling schemes, appropriate channel access protocols, improved schemes for retransmission, and optimal packet size at MAC layer. The major objective of this book is to examine the challenges and issues at MAC layer with an in-depth analysisofstate-of-the-artprotocolsbasedonIEEE802.15.4.Inaddition,thisbook also presents the design and evaluation of an adaptive MAC protocol for medical CPS, which exemplifies how to achieve real-time and reliable communications in CPS by exploiting IEEE 802.15.4-based MAC protocols. This book will be of interest to researchers, practitioners, and students to better understand the QoS requirements of CPS at MAC sublayer. Over the years there have been many people working in the field of CPS. The literature helped us gain the knowledge necessary for our research, which makes this book possible. We would like to thank Xiangjie Kong, Tie Qiu, Ruixia Gao, Linqiang Wang, Ruonan Hao, Yang Cao, Lei Xue, Daqiang Zhang, Daojing He, Alexey Vinel, Nadeem Javaid, Muhammad Aslam, Ziaur Rahman, U. Qasim, and Z.A.Khanfortheircontributionstotheworkreportedinthisbook.Wearegrateful toallmembersoftheMobileandSocialComputingLaboratory,aswellastoAsim v vi Preface Idrees and Muhammad Farshad Panhwar for their help in realizing this book. This work is partially supported by Natural Science Foundation of China under Grant No. 60903153. Dalian, China Feng Xia September 2014 Azizur Rahim Contents 1 Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.1 Cyber-Physical Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.1.1 What Is CPS? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 1.1.2 Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 1.1.3 General Requirements . . . . . . . . . . . . . . . . . . . . . . . . . 3 1.2 Wireless Body Area Networks: A Case of CPS. . . . . . . . . . . . . 4 1.2.1 Architecture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 1.2.2 Design Issues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 1.2.3 Energy Dissipation. . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 1.3 Overview of the Book . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 2 MAC Protocols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 2.1 Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 2.2 Classification of MAC Protocols . . . . . . . . . . . . . . . . . . . . . . . 12 2.2.1 Contention-Based MAC Protocols . . . . . . . . . . . . . . . . . 12 2.2.2 Contention-Free MAC Protocols . . . . . . . . . . . . . . . . . . 14 2.2.3 Low Power Listening (LPL) MAC Protocols. . . . . . . . . . 14 2.3 MAC Protocols for WBAN. . . . . . . . . . . . . . . . . . . . . . . . . . . 15 2.3.1 Battery-Aware TDMA Protocol. . . . . . . . . . . . . . . . . . . 15 2.3.2 Priority-Guaranteed MAC Protocol. . . . . . . . . . . . . . . . . 16 2.3.3 Energy-Efficient Low Duty Cycle MAC Protocol . . . . . . 17 2.3.4 A Power-Efficient MAC Protocol for WBANs . . . . . . . . 18 2.3.5 Energy-Efficient Medium Access Protocol . . . . . . . . . . . 18 2.3.6 BodyMAC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 2.3.7 MedMAC. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 2.3.8 Heartbeat-Driven MAC Protocol . . . . . . . . . . . . . . . . . . 21 2.4 Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 2.5 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 vii viii Contents 3 Evaluating IEEE 802.15.4 for CPS . . . . . . . . . . . . . . . . . . . . . . . . 25 3.1 Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 3.2 IEEE 802.15.4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 3.2.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 3.2.2 MAC Sublayer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 3.2.3 Superframe Structure . . . . . . . . . . . . . . . . . . . . . . . . . . 28 3.2.4 Contention Access Period (CAP). . . . . . . . . . . . . . . . . . 29 3.2.5 Contention Free Period (CFP). . . . . . . . . . . . . . . . . . . . 29 3.2.6 Inter Frame Spacing (IFS). . . . . . . . . . . . . . . . . . . . . . . 29 3.2.7 CSMA/CA Mechanism. . . . . . . . . . . . . . . . . . . . . . . . . 30 3.3 Simulation Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 3.4 Non-beacon-Enabled Mode. . . . . . . . . . . . . . . . . . . . . . . . . . . 34 3.4.1 Impact of MSDU Size . . . . . . . . . . . . . . . . . . . . . . . . . 34 3.4.2 Impact of Packet Generation Interval . . . . . . . . . . . . . . . 36 3.4.3 Impact of MaxNB . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 3.4.4 Impact of MinBE. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 3.4.5 Impact of MaxFrameRetries . . . . . . . . . . . . . . . . . . . . . 40 3.5 Beacon-Enabled Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 3.5.1 Impact of MaxNB . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 3.5.2 Impact of SO . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 3.5.3 Impact of BO . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47 3.6 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 4 IEEE 802.15.4 Based Adaptive MAC Protocols . . . . . . . . . . . . . . . 53 4.1 Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53 4.2 Approaches for Contention Access Period. . . . . . . . . . . . . . . . . 54 4.2.1 Adaptive Backoff Exponent Mechanism. . . . . . . . . . . . . 56 4.2.2 Adaptive Contention Window Mechanism. . . . . . . . . . . . 58 4.3 Approaches for Contention-Free Period. . . . . . . . . . . . . . . . . . . 60 4.3.1 Adaptive GTS Allocation Scheme . . . . . . . . . . . . . . . . . 61 4.3.2 Implicit Allocation Mechanism . . . . . . . . . . . . . . . . . . . 62 4.3.3 Knapsack Algorithm . . . . . . . . . . . . . . . . . . . . . . . . . . 62 4.3.4 GTS Scheduling Algorithm. . . . . . . . . . . . . . . . . . . . . . 63 4.4 Cross-Period Approaches . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65 4.5 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66 5 An Adaptive MAC Protocol for Medical CPS . . . . . . . . . . . . . . . . 69 5.1 Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69 5.2 The Ada-MAC Protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70 5.2.1 Superframe Structure . . . . . . . . . . . . . . . . . . . . . . . . . . 70 5.2.2 Priority Queue Mechanism . . . . . . . . . . . . . . . . . . . . . . 71 5.2.3 Adaptive Mini-Slot Allocation. . . . . . . . . . . . . . . . . . . . 72 Contents ix 5.3 Simulation Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76 5.4 Results and Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78 5.4.1 Mean/Max End-to-End Delay . . . . . . . . . . . . . . . . . . . . 78 5.4.2 On-Time Delivery Ratio. . . . . . . . . . . . . . . . . . . . . . . . 80 5.4.3 Packet Drop Rate (by Queue) . . . . . . . . . . . . . . . . . . . . 81 5.4.4 Packet Loss Rate. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83 5.4.5 Effective Utilization Rate of CFP. . . . . . . . . . . . . . . . . . 84 5.5 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85 6 Conclusion. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87 6.1 Summary of the Book . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87 6.2 Open Issues. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89