EXAMENSARBETE INOM ELEKTROTEKNIK, AVANCERAD NIVÅ, 30 HP STOCKHOLM, SVERIGE 2016 Experimental Study of Thread Mesh Network for Wireless Building Automation Systems DAPENG LAN KTH SKOLAN FÖR ELEKTRO- OCH SYSTEMTEKNIK i KTH ROYAL INSTITUTE OF TECHNOLOGY Abstract Master of Science Experimental Study of Thread Mesh Network for Wireless Building Automation Systems by Dapeng LAN Wireless sensor network technologies have gained significant popularity in home automation due to their scalability, system mobility, wireless connec- tivity, inexpensive and easy commissioning. Thread, a new wireless pro- tocol aiming for home automation, is proposed by Google Nest and stan- dardized by Thread Group. This thesis presents a thorough experimental evaluation of Thread wire- less protocol with the hardware platform from NXP. The test plan, imple- mentation, and analysis of the experiments is discussed in details, including signal coverage, unicast and multicast latency, reliability, and availability. Furthermore, a system level model considering the delay in different layers for the latency of Thread mesh network is presented, and validated by the experimental results. Finally, a friendly tool was developed for installers to estimate the latency of Thread mesh network. ! ! ! ! ! ! ! ! ! Sammanfattning) ! Trådlösa) sensornätverk) har) fått) betydande) popularitet) för) hemautomation) på) grund) av) deras) skalbarhet,) systemmobilitet,) trådlösa) konnektivitet,) låga) prisnivå) och) enkla) implementation.) Thread,)ett)nytt)trådlöst)protokoll)avsett)för)hemautomation,)är) föreslaget)av)Google)Nest)och)standardiserat)av)Thread)Group.) ) Denna) uppsats) presenterar) en) ingående) experimentell) utvärdering) av) det) trådlösa) ThreadAprotokollet) med) en) hårdvaruplattform)från)NXP.)Testplanen,)implementationen)och) analysen)av)experimenten)diskuteras)i)detalj)innehållandes)signal) täckning,) unicast) och) multicast) latens) samt) tillgänglighet.) Dessutom) presenteras) en) modell) på) systemnivå) som) tar) fördröjningar) i) olika) lager) för) latensen) i) ThreadAnätverket) i) hänseende,) vilken) även) är) validerad) genom) testresultaten.) Slutligen,) utvecklades) ett) användarvänligt) verktyg) för) installationspersonal) för) att) estimera) latensen) i) ThreadAmeshA nätverket.))) ) iii Acknowledgements First and foremost, I would like to thank my research supervisor in ABB corporate research, Zhibo Pang, for his constant guidance, enthusi- asm, knowledge and offering the opportunity to investigate the state-of-art WSN protocol - Thread. Also I would like to thank my co-supervisor, Gargi Bag, for her patience toward solving my confusions and her kindly encour- agement. This paper would never be accomplished without their valuable assistance and dedicated involvement. Furthermore, I would like to thank my examiner, Carlo Fischione. Besides, I would like to thank my research group members Eva Azoidou and Yu Liu. They gave me support during my research period and helped me spend pleasurable life in ABB. It is difficult to mention all friends I have met in ABB and KTH, whom I have learnt a lot of things from and offered me unforgettable experience. Thanks to all of them. Finally, I would like to thank my parents for giving me any kinds of support substantially and spiritually throughout my studying life. v Contents Abstract i Acknowledgements iii 1 Introduction 1 1.1 Background ............................ 1 1.2 Problem Statement ........................ 2 1.3 Methodology ........................... 2 1.4 Contribution of the Thesis .................... 3 1.5 Outline ............................... 3 2 Related work in Wireless Sensor Networks 5 2.1 From Non-IP to Native IP .................... 5 2.2 Overview of the IEEE 802.15.4 standard ............ 5 2.2.1 Non-beacon enabled IEEE 802.15.4 CSMA/CA .... 6 2.3 IETF IoT stacks .......................... 7 2.3.1 6LoWPAN ......................... 7 2.3.2 RPL ............................. 8 2.3.3 CoAP ............................ 9 2.4 Overview of Thread protocol .................. 9 2.4.1 Protocol stacks ...................... 9 2.4.2 Device types ........................ 10 2.4.3 Multicast Protocol for Low power and lossy networks (MPL) ........................... 11 2.4.4 Comparison with other protocols ............ 11 2.5 Other protocols .......................... 12 2.5.1 Zigbee ........................... 12 2.5.2 WirelessHART and ISA100 ............... 12 3 Test plan 15 3.1 Signal Coverage .......................... 15 3.2 Unicast latency and reliability .................. 16 3.3 Multicast latency and reliability ................. 17 3.4 Availability ............................. 18 4 Experimental Setup 19 4.1 Test platform ............................ 19 4.2 Signal Coverage Setup ...................... 20 4.3 Unicast Latency and Reliability Setup ............. 20 4.4 Multicast Latency and Reliability Setup ............ 23 4.5 Availability Test Setup ...................... 24 vi 5 Result Analysis 25 5.1 Signal Coverage .......................... 25 5.2 Unicast and Reliability ...................... 26 5.3 Multicast and Reliability ..................... 29 5.4 Availability ............................. 30 6 Modeling and Validation of Latency in the Thread Mesh Network 31 6.1 System model of latency of multihop Thread mesh network 31 6.2 Numerical results and experimental validation ........ 33 6.2.1 Statistical probability distribution of MAC service time 34 6.2.2 Latency related to hardware and software implemen- tation ............................ 34 6.2.3 Experimental validation of Thread mesh network .. 35 6.2.4 Software tool to estimate the latency of Thread mesh network .......................... 35 7 Conclusion and Future work 39 7.1 Conclusions of the work ..................... 39 7.2 Future work ............................ 40 Bibliography 41 vii List of Figures 1.1 The portal of research methods and methodologies(Håkansson, 2013) ................................ 3 2.1 The unslotted IEEE 802.15.4 CSMA/CA channel access mech- anism ................................ 7 2.2 IETF LLN protocol stack ..................... 8 2.3 Thread protocol stacks. ...................... 10 2.4 Thread device types(Threadgroup official website) ........ 10 3.1 Definition of round trip time ................... 16 4.1 Hardware platform - FRDM-KW24D512 ............ 19 4.2 Signal coverage test setup .................... 20 4.3 Thread mesh network topology ................. 20 4.4 Communication between laptop and border router ...... 21 4.5 nodes placement in the building ................ 22 4.6 Deployment of Nodes in the building for multicast test ... 23 5.1 Latency result of 6 hops for 4 test cases ............. 26 5.2 Packet delivery ratio with the deadline 50ms, 100ms, 150ms, 200ms ................................ 27 5.3 Comparison between 4 cases with respect to different hops . 28 5.4 CDF of TCC in multicast latency test .............. 29 5.5 Availability result of Thread mesh network with 38 nodes .. 30 6.1 System model of the latency of Thread mesh network .... 31 6.2 latency of different layer in Thread network .......... 31 6.3 MAC service time distribution. (a) shows the relationship between the probability distributions and the nodes numbers N with λ = 0.2. (b) shows the relationship between the the probability distributions and λ with N = 10. .......... 33 6.4 experimental test of PHY layer latency (A) and IPS layer la- tency (B) .............................. 33 6.5 Unicast latency results for 6-hop mesh network of Thread: (A) case 1 (B) case 4 ........................ 37 6.6 Software tool to estimate the latency of Thread mesh network 38 ix List of Tables 2.1 Thread compare with other protocols ............. 12 3.1 Unicast latency test plans .................... 17 3.2 Multicast latency test plans ................... 17 4.1 Experimental setup parameters for unicast latency ...... 22 4.2 Experimental setup parameters for multicast latency ..... 23 4.3 Experimental setup parameters for availability test ...... 24 5.1 Signal coverage result (meters) ................. 25 5.2 Statistics of the Round Trip Time (RTT) ............. 27 5.3 Reliability of multicast ...................... 29 5.4 Statistics of the Time for Complete Coverage (TCC) ..... 29 6.1 Experimental data of the Thread latency in different layers with data length 10 Bytes ..................... 35 xi List of Abbreviations 6LoWPAN IPv6 over Low power Wireless Personal Area Networks ACK Acknowledgement BA Building Automation BAS Building Automation System BPSK Binary Phase-Shift Keying BR Border Router CCA Clear Channel Assessment CDF Cumulative Distribution Function CoAP Constrained Application Protocol CSMA/CA Carrier Sense Multiple Access with Collision Avoidance DSSS Direct Sequence Spread Spectrum ED End Device IEEE Institute of Electrical and Electronics Engineers IETF Internet Engineering Task Force IoT Internet of Things IP Internet Protocol IPv6 Internet Protocol version 6 LLNs Low-Power and Lossy Networks MAC Media Access Control MCU Microcontroller MTU Maximun Transmission Unit MTTF Mean Time To Failure MTTR Mean Time To Repair NIP Native Internet Protocol NWK Network layer O-QPSK Offset Quadrature Phase-Shift Keying OS Operating System OSI Open System Interconnection OTA Over The Air PER Packet Error Rate PDR Packet Delibery Ratio PHY Physical PGF Probability Generation Function PLC Power Line Communication SPI Serial Peripheral Interface RPL IPv6 Routing Protocol for Low-Power and Lossy Networks RSSI Received Signal Strength Indicator