big trends

DOI:10.1145/3312563

BY JULIE A. MCCANN, GIAN PIETRO PICCO, ALEX GLUHAK, KARL HENRIK JOHANSSON, MARTIN TÖRNGREN, AND LAILA GIDE Connected Things Connecting Europe

to exchange data, optimize processes, monitor environments, and typically consist of sensors, actuators, and low- IT IS ESTIMATED that personal computers, datacenters, power compute infrastructures. CPS is and other technologies constitute less than 1% of all a term first coined in 2006 in the U.S. to 10 characterize “the integration of physical microprocessor usage; embedded systems represent systems and processes with networked the remaining percentage and can be found in our computing” for systems that “use com- putations and communication deeply washing machines, microwaves, remote controls, embedded in and interacting with phys- and PC peripherals (such as keyboards and mobile ical processes to add new capabilities phones), with modern cars containing many tens of to physical systems.”22 CPS is generally 18 put forward as the more systems notion, embedded microcontrollers. Modern embedded- while IoT emphasizes communication system microcontroller and transceiver technology and analytics, yet IoT-like devices need advancements have brought forth the kinds of systems not always use Internet protocols to create a CPS, hence the ambiguity. The we have in the past defined as pervasive, ubiquitous, European Commission debated for two and embedded computing, and for some time in years whether to call its embedded in- telligence programs CPS, with the latter Europe, “embedded intelligence.” However, today they winning out in the end. In this article, we are better known as the (IoT) and embrace these terms fluidly and name cyber-physical systems (CPS); see the figure here. them IoT/CPS; for other definitions, see the sidebar “Some Definitions.” The jury is still out regarding a definition of the In essence, the terms represent latter two terms or indeed how to differentiate them, different perspectives on the techno- logical advancements that have led to but people generally tend to refer to IoT as creation of many related application embedded devices that connect to the Internet terms—industry 4.0, smart cities, preci-

46 COMMUNICATIONS OF THE ACM | APRIL 2019 | VOL. 62 | NO. 4 sion agriculture, smart transport, and coined the phrase the reaping the advantages of standard- autonomous vehicles—all representing “Internet of Things.” His vision of con- ization and the software-engineering new classes of technologically enabled necting sensor- and actuator-based experience that programmers already systems. Recent studies have predicted technology to the Internet unfolded an had from other Internet systems. the impact of IoT/CPS on the European active area of technological advance- Adam Dunkels of SICS in Swe- Union’s GDP in 2025 by sector, with ment around the world that only in the den developed the operating “transportation” being forecast to cre- past few years has begun to find larger- system that has significantly grown ate the greatest value, with a total of scale adoption and is finally becom- in popularity, particularly over the €245 billion alone, followed closely by ing a commercial reality. In parallel, past decade. As the technology ma- “healthcare,” “housing,” and “indus- the University of California, Berkeley’s tured, device hardware could pack try.”1 As in the rest of the world, Euro- TinyOS and Mote hardware combina- more compute power for the same pean countries and the European Com- tion dominated early academic ex- energy budget, and the resource sav- mission have invested heavily in IoT/ perimental work on wireless sensor ings TinyOS delivered thus became CPS research, almost €200 million, re- networks, also making its way into var- less important. Exploiting this power, sulting in many cross-discipline, cross- ious commercial products. While the Contiki’s advantage over its pred- country technology advancements U.S. focused on designing new pro- ecessors lay in its flexibility and ease unique in terms of their focus on the in- tocols and approaches to overcome of coding applications. Indeed, today tegration of such systems, particularly the intrinsic limitations of resource- hackers, academic institutions, and at scale, their underpinning communi- constraint IoT/CPS devices, the focus companies are using Contiki because cations substrates, and, more recently, in Europe was more on the integra- it remains lightweight, mature, and their security and relationship to priva- tion of such systems to fulfil real ap- free; for example, Texas Instruments cy. In this article we describe highlights plication needs. In particular, tools (a U.S. company) ships many of its IoT/ of this work in more detail and present to aid the building of devices and, CPS devices (such as Sensortag) with what we believe are the main outstand- moreover, their applications became the option of using Contiki. ing challenges facing the field for Eu- the European emphasis, resulting in At that time, the prevalent commu- rope over the next decade. mechanisms to ease programming nications protocols operated over low- and systems engineering and, more data-rate, local-area networking (up to The Integrated Approach important, make such systems a natu- approximately 50-meter distances) ra-

IMAGE BY GARRY KILLIAN GARRY BY IMAGE Two decades ago, a European named ral extension of the Internet, the latter dio transmissions. 802.15.4-based pro-

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tocols (such as ZigBee, designed in the ETH Zurich and others advocated for tium of multinational telcos, including U.S.) overcome these short distances by such devices to become first-class citi- Telefónica (Spain), Orange (formally providing multi-hop communications, zens in the current Web. His pioneer- French Telecom), and others, to a suite allowing data to be relayed between ing work led to what is now known as of more than 50 components to create devices to form longer-distance routes the , with active work (as value from real-world applications en- and hopping the data from device to part of W3C) receiving support from abled by the ubiquity of heterogeneous device. However, in Europe, for re- Siemens, Google, and other sources.6 and resource-constrained devices. An- searchers (such as Dunkels), the quest The increasing investment in CPS/ other example is from the ARTEMIS was now to push the Internet Protocol IoT throughout Europe, and the world, Industry Association,9 with more than all the way down to small embedded has meant an increase in the number 170 members and associates from all devices themselves.2 Early attempts of systems, protocols, and applica- over Europe, and the European IoT include the work of Zach Shelby, an tions being built. Also, there was little Platform Initiative Programme (IoT American, working at Oulu Universi- integration between systems, as seen EPI), a €50 million programme with ty,3 but the now-ubiquitous 6LowPAN especially in the smart-city domain. nine projects involving more than 40 protocol has emerged to provide light- This fragmentation is thought to have different IoT platforms exploring mul- weight end-to-end Internet connectiv- undermined the confidence of stake- tiple approaches to interoperability.11 ity down to the smallest devices and holders and market opportunities, An example of where Europe leads has gradually replaced the previously affecting IoT adoption, thus causing in living-lab deployments is the Smart- popular ZigBee communications ap- Europe to become increasingly fo- Santander testbed in Santander, Spain, proach. cused on the applications built on top a prominent European experimental While 6LowPAN allowed for more of IoT/CPS systems and their integra- infrastructure for IoT/CPS. By embed- efficient raw Internet communica- tion.7 Indeed the perception in Europe ding a large number of diverse sensor tion, the next logical step was to make was that while U.S. IoT/CPS innovation devices into a city environment, it al- it Web friendly by replacing its heavy focused on adoption environments lowed a variety of use cases Web protocol with a more lightweight based on individual business cases to be explored. While initially useful one. Work emanating from European driven by economic return on invest- for experiments with IoT protocols and large-scale mixed academic/industrial ment, Europe’s industry and academic data-driven services, the infrastructure projects (such as SENSEI and FP7) fo- researchers focused on the exploration is now part of the Santander’s day-to- cused on how such emerging wireless of societal benefits and acceptance of day operation, improving the lives of its sensor and actuator networks can be CPS/IoT technology generally. citizens. Since its beginnings in 2010, more effectively integrated into a fu- One major success resulting from more than 12,000 sensor devices have ture Internet.4 Shelby worked with the the European joint research and in- been deployed across the city to help Internet Engineering Task Force (IETF) dustrial projects is FIWARE, a curated the government operate as efficiently and such companies as England’s ARM framework of open source-platform, as possible through such applications low-power processor design company, market-ready components to acceler- as adaptive traffic management, smart ultimately producing the COAP proto- ate development of IoT/CPS systems parking, water management, intelli- col5 used to make applications on low- and their integration with cloud ser- gent streetlights, and waste disposal. power devices easier to program. At vices.8 Since its beginnings in 2012, SmartSantander went on to inspire about the same time, Dom Guinard at FIWARE has evolved from a consor- other initiatives around the world, in-

Timeline of some key IoT events.

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cluding the Array of Things project in fluid, with several technologies (both SigFox is still a telco operator, having to Chicago. competing and complementary) offer- manage access to its own network and Both testbeds and living labs21 paved ing disruptive opportunities unthink- based on proprietary technology. In the way for IoT large-scale pilots in Eu- able only a few years ago. Interestingly, contrast, LoRa,17 which was developed rope, a €100M R&I program that com- several of these trends are the result of by Cycleo of Grenoble, France, and ac- menced in 2017.12 Examples of such achievements by European researchers quired by Semtech in 2012, used radio projects include SynchroniCity (eight and companies, as we highlight here. technology based on chirp spread spec- smart-city pilots13), MONICA (IoT tech- A prominent example is a new class trum modulation to effect low-power nologies to manage sound and security of communications mechanisms de- wide-area transmission. The LoRa Al- at large, open-air cultural and sport- scribed as “low-power wide-area net- liance then defined a public suite of ing events14), and IoF2020 (Internet of works” (LPWANs) that recently revealed protocol specifications (LoRaWAN) Food and Farm 2020 with 70 partners trade-offs in the amount of power they that allows a telco operator to deploy its from 16 European countries15); many require from the device, geographic own networks but also enables deploy- of these projects are associated with, coverage or distances they send data, ment and operation of privately owned and continue to use, the FIWARE infra- and data rates. Until a few years ago, networks operating side-by-side. Both structures. long-range communication was a privi- SigFox and LoRa have their main center lege of cellular telephone communica- of gravity in Europe; for instance, of the Underpinning tion, where devices were fitted with SIM 5,000+ gateways deployed today, 3,000+ Communications Technologies cards and communicated typically over are in Europe. This is also reflected in The communications substrate in an 2G GPRS networks. This did not match the surge of competing, industry-driven IoT/CPS architecture plays a crucial with the low-power nature of CPS/IoT approaches, among which, arguably role, and low-power wireless connec- devices and meant they were required the most prominent, is Huawei’s NB- tivity is fundamental to balancing con- to be plugged into the mains, limiting IoT. Indeed, today’s version of NB-IoT, nectivity performance with low-power where they could be placed or receive which is being specified by the 3GPP, an system capabilities and lifetimes. Free- frequent battery changes, and many international body of telcos, originated dom from power and data cables pro- stakeholders were reluctant to rely sole- in early work by NEUL, a company from vides mobility and autonomy of devices ly on proprietary networks and devices Cambridge, U.K., that developed the that are readily deployed and relocated, owned by operators. Weightless protocol and was bought can improve performance, and follow SigFox16 based in France was in out in 2014 by Huawei. LPWA technolo- the users and objects they are attached 2009 the first to use ultra-narrowband gies are not being rolled out worldwide. to, or even move of their own volition, modulation to enable longer-distance Where LPWA supports slow data as with robots and drones. In recent de- communications while remaining low over great distances, ultra-wideband cades, wireless communications was power. Since the first deployments that (UWB) communications permits high- dominated by Wi-Fi and cellular com- covered the entire country of France, er data volumes and speeds over short munications that were ubiquitous yet SigFox showed its technology can pro- distances. Originally used for military energy-hungry; low-power alternatives vide coverage like cellphone commu- applications, UWB became unlicensed had to emerge, as embodied by ZigBee nications but without the need for a in 2002, but a new wave of interest in 2004. Today, the wireless communi- SIM card and at significantly less cost has followed a small Irish company cation landscape is significantly more in terms of money and energy. But called DecaWave19 when it released the

Timeline of some key IoT events.

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(black-box behavior), robustness, pre- dictability (such as when data is out- side a training set), and how to cost-effi- Some Definitions ciently verify, validate, and assure such Microcontroller. Computer on a single chip, with one or more processor cores, memory, systems.29,30 In addition, CPS systems and input/output peripherals. must function in increasingly complex Sensor nodes/mode. Generic way to describe sensor-based devices, typically consisting environments, as in automated driving. of several sensors and radio communications module(s) governed by a microcontroller. Describing such varying environments Different from phones and traditional computers, they are a few centimeters in size and systematically dealing with uncer- without keyboard or screen. An example is the University of California, Berkeley, TMote Sky sensor node consisting of the CC2420 ZigBee near-range communications, an tainty represent further key challenges MSP430 low-power microcontroller packed into a matchbox-size form factor. that have been addressed in such Euro- pean research projects as Pegasus31 and Actuator. A device that controls other devices (such as valves and switches). the U.K. EPSRC-funded S4: Science for European Research Council. A body that funds technological research in the EU. Its Sensor Systems in 2016.32 framework funding programs include FP7 (Framework Programme) finished in 2013, Safety and security engineering giving way to H2020 (Horizon 2020). On top of this, each EU country also has national funding infrastructures, as in EPSRC in the U.K. and DFG in Germany. concerns the connectivity and spread of CPS and provides new attack surfac- IETF. The IETF is a large open international community of network designers, operators, vendors, and researchers concerned with the evolution of Internet architecture and es that could exploit vulnerabilities in smooth operation of the Internet; for more, see https://www.ietf.org/about/ the cyber and/or physical side, as well as among human stakeholders. This implies existing security approaches DW1000 chip, overcoming many of to ensure future CPS systems are suf- are not suitable. Moreover, security bulkiness and power-consumption is- ficiently safe, secure, available, privacy- may affect safety, thus calling for in- sues and storming the field of real-time preserving, and overall trustworthy. A tegrated and balanced security and location-tracking systems. Indeed, the science for CPS engineering is needed. safety trade-offs and development of potential here is enormous, especially Europe is positioned well in this regard new methodologies. The widespread if UWB chips eventually find their way to address the key challenges of com- use of CPS systems and their increas- into smartphones where UWB could plexity management, safety, and secu- ing automation imply that existing trigger a new wave of location-based rity by design and privacy. safety-engineering approaches are IoT/CPS services with an impact com- Complexity management of IoT/ not sufficient, and, in particular, that parable to (if not greater than) that CPS systems is important because they future CPS will need to deal with risk achieved by GPS. inherit the complexity of their cyber explicitly, incorporating measures and physical parts. There is a lack of of dynamic risk, as compared, again, Trust, Safety, Security, approaches to systematically accom- with automated driving. An example Privacy (Guarantees) plish “composability” of CPS compo- of security research in Europe comes CPS and IoT provide unprecedented nents, meaning achieving integration from the £23M PETRAS Research Hub capabilities and opportunities for of CPS components is difficult with- in the U.K., which involves 60 projects the benefit of society. But it will be out negative, sometimes unknown, researching the various aspects of IoT/ achieved through corresponding un- side effects, or emerging behaviors.28 CPS security, from devices to social precedented technological complex- Composability for CPS must address practice, and have produced a land- ity that also introduces new risks that the multifaceted dependencies in CPS mark report, The Internet of Things: Re- need to be recognized, debated, and across components, functions, and alising the Potential of a Trusted Smart dealt with appropriately. This is essen- system-level properties. An example World,33 co-produced with the Royal tial since future CPS and IoT will be of a European stronghold is the effort Academy of Engineering. widespread and underpin a large num- driven by Kopetz on composable time- It is infeasible to predict all possi- ber of critical societal infrastructures, triggered architectures, with research ble faults, threats, and failure modes including water, energy, transporta- funded through several EU projects for future CPS. Systems will have to tion, and healthcare, all relying on the that have influenced many commu- be resilient, with built-in build moni- proper operation of the technologies. nication protocols for CPS, delivered tors and error handlers to ensure cost- A key concern is that current engi- reusable architectural services for efficient dependability. Examples of neering methodologies are generally exploitation across platforms of dif- European efforts include the MBAT viewed as inadequate for next-genera- ferent domains (INDEXYS project in project that gave European industry a tion CPS. Consequently, multiple calls 2008), and paved the way for success- leading-edge affordable and effective have been issued from the EU for new ful companies like TTTech.20 validation-and-verification technol- methodologies, including Platform- The use of machine learning, par- ogy in the form of a Reference Tech- 4CPs,25 AENEAS,26 and the Acatech ticularly deep learning, provides a nov- nology Platform (the MBAT RTP) and National Academy of Science and En- el technology within CPS. While such the AQUAS project, which is devel- gineering.27 The full potential of future technologies enable entirely new types oping solutions for safety/security/ CPS can be obtained only when new en- of applications, they raise concerns performance co-engineering, as in gineering methodologies are in place about how to deal with transparency Sillitto.34 Europe has a strong tradi-

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tion in dependability and engineer- effect reaches much farther than just EE Times (May 1, 1999); https://www.eetimes.com/ author.asp?section_id=36&doc_id=1287712 ing of trustworthy systems, notably Europe. 11. https://iot-epi.eu/ through the ARTEMIS and ECSEL 12. https://european-iot-pilots.eu/ 13. https://synchronicity-iot.eu/ private-public partnerships. Example Conclusion 14. https://european-iot-pilots.eu/project/monica/ projects include Pegasus, funded by We have drawn out three views of 15. https://european-iot-pilots.eu/project/iof2020-2/ 16. https://www.sigfox.com the German Federal Ministry for Eco- IoT/CPS systems the European ap- 17. https://lora-alliance.org/ nomic Affairs and Energy and involv- proach to research contributes to in 18. Fleming, B. Microcontroller units in automobiles. IEEE Vehicular Technology Magazine 6, 3 (2011), 4–8. ing all major German OEMs and Tier 1 its own unique way, though European 19. https://www.decawave.com/ companies to produce mechanisms to researchers continue to collaborate 20. http://www.indexys.eu/ 21. Open Living Labs; https://enoll.org/ test and formally verify autonomous across the globe to address the many 22. Lee, E.A. and Seshia, S.A. Introduction to Embedded Systems: A Cyber-Physical Systems Approach. MIT vehicles. And SCOTT is examining challenges associated with these sys- Press, Cambridge, MA, 2016. frameworks to enable development tems. This subject continues to grow 23. Gadotti, A., Houssiau, F., Rocher, L., and de Montjoye, Y.A. When the signal is in the noise: The of secure and connected trustworthy and, with it, new problems. For ex- limits of Diffix’s sticky noise. 2018;arXiv preprint things primarily for the rail-transport ample, as such systems contribute to arXiv:1804.06752 35 24. Istomin, T. et al. Data prediction + synchronous industries. Separately, the TrustLite the autonomy of cars, water networks, transmissions = ultra-low-power wireless sensor security framework from the Intel precision farms, and more, the more networks. In Proceedings of the 14th ACM Conference on Embedded Network Sensor Systems, 2016. Collaborative Research Institute for we need to be able to understand how 25. Platforms4CPS: Final recommendations; https://bit. Secure Computing (a collaboration of to engineer them and provide guaran- ly/2BodgrP 26. AENEAS, ARTEMIS Industry Association, EPoSS. TU Darmstadt, University of Helsinki, tees regarding their operation. How- Strategic Research Agenda for Electronic Components and other European security insti- ever, as we do not fully understand and Systems, 2018; https://efecs.eu/publication/ download/ecs-sra-2018.pdf tutes) have produced an Execution- how digital systems interact with the 27. Acatech National Academy of Science and Aware Memory Protection Unit that physical world, we do not yet have such Engineering. Living in a Networked World. Integrated Research Agenda Cyber-Physical Systems, 2015; provides programmable operating guarantees. We thus need a science http://www.cyphers.eu/sites/default/files/acatech_ system-independent isolation of soft- of cyber-physical interaction; related STUDIE_agendaCPS_eng_ANSICHT.pdf 28. Törngren, M. and Grogan, P.T. How to deal with the ware modules at runtime for low-cost design principles will then emerge, complexity of future cyber-physical systems? Journal of Designs 2, 4, 2018; http://www.mdpi.com/2411- embedded devices. much as they have in other engineer- 9660/2/4/40 IoT/CPS systems are constantly ing disciplines. Given the importance 29. Wagner, M. and Koopman, P. A Philosophy for Developing Trust in Self-driving cars. In Road Vehicle monitoring homes, factories, cars, of the communications substructure Automation, G. Meyer and S. Beiker, Eds. Lecture and more, and while understanding for such systems, the jury is still out as Notes in Mobility. Springer, Cham, Switzerland, 2015, 163–171. these processes can make them more to which protocol (or set) will win. 30. Amodei, D., Olah, C., Steinhardt, J., Christiano, P., efficient, sustainable, and safe, they There are many players in the LPWA Schulman, J., and Mané, D. Concrete Problems in AI Safety. 2016; arXiv:1606.06565 can expose privacy concerns. The most game, but the big question is what will 31. https://www.pegasusprojekt.de/en/about-PEGASUS prominent European initiative affect- be the effect of the promised 5G suite 32. Calder M., Dobson, S., Fisher, M., and McCann, J. Making Sense of the World: Models for Reliable ing IoT/CPS data gathering is that of of solutions? Finally, as these systems Sensor-Driven Systems, Mar. 28, 2018; arXiv preprint the General Data Protection Regula- take more control of our lives, their arXiv:1803.10478 33. http://www.oerc.ox.ac.uk/news/Centre-contribution- tion (GDPR) regarding data protection ethical approach is key, including the IoT-reports for individuals in the EU and its eco- ability to maintain privacy while still 34. Sillitto, H. Architecting Systems: Concepts, Principles and Practice. Volume 6: Systems. College Publications, 36 nomic area. The European approach being useful. Indeed, their security is London, U.K., 2014. to privacy is that, through GDPR, all the of paramount importance, as being 35. https://www.indracompany.com/en/indra/scott- secure-connected-trustable-things requirements of data domains and ter- able to hack a water network or auton- 36. https://eur-lex.europa.eu/eli/reg/2016/679/oj 37. De Montjoye, Y.-A. et al. Unique in the crowd: ritories are consolidated into a single omous vehicle could mean disaster. The privacy bounds of human mobility. Scientific coherent and well-defined regulation. There is plenty of research for Europe Reports 3 (2013), 1376; http://www.nature.com/ One aspect of this is that a data owner and beyond to consider. srep/2013/130325/srep01376/full/srep01376.html must prove its data protection reason- ably matches the current state of the art, References Julie A. McCann is a professor of computer systems 1. https://www.statista.com/statistics/686173/iot-s- in the Department of Computing at Imperial College, which in turn uniquely drives practical impact-on-gdp-in-the-european-union-eu-by-sector/ London, U.K. anonymization research. Researchers 2. Dunkels, D. Full TCP/IP for 8-bit architectures. In Gian Pietro Picco is a professor in the Department of Proceedings of the 1st ACM/Usenix International Information Engineering and Computer Science at the aim to demonstrate privacy shortfalls Conference on Mobile Systems, Applications and University of Trento, Italy. Services (San Francisco, May 2003). to make schemes more robust. For ex- Alex Gluhak is head of technology at Digital Catapult, 37 3. Shelby, Z., Mahonen, P., Riihijarvi, J., Raivio, O., ample, U.K. and Belgium researchers and Huuskonen, P. NanoIP: The Zen of embedded Guildford, U.K., were able to prove it took only four lo- networking. In Proceedings of the IEEE International Karl Henrik Johansson is a professor in the School of Conference on Communications (Anchorage, AK, Electrical Engineering and Computer Science at KTH cation points to be able to uniquely 2003), 1218–1222. Royal Institute of Technology, Stockholm, . identify someone 95% of the time and 4. https://tools.ietf.org/id/draft-shelby-core-coap-req-01. html Martin Törngren is a professor of embedded control that data coarsening and noise addi- 5. http://coap.technology/ systems in the Department of Machine Design at KTH tion do not help. This was followed by 6. http://www.usa.siemens.com/en/about_us/research/ Royal Institute of Technology, Stockholm, Sweden. web-of-things.htm and https://github.com/google/ 23 Laila Gide is Past-President, ARTEMIS Industry Gadotti et al., who showed privacy physical-web Association, and Past-Director, Advanced Studies Europe techniques using “sticky noise” could 7. http://www.internet-of-things-research.eu/pdf/IERC_ in the Corporate Strategy, Marketing and Technical Position_Paper_IoT_Semantic_Interoperability_Final. Directorate, Amsterdam, The Netherlands. be easily infiltrated. All European citi- pdf 8. https://www.fiware.org/about-us/ zens, as well as those only visiting Eu- 9. https://artemis-ia.eu/project/59-3car.html rope, are covered by GDPR, meaning its 10. Turley, J. Embedded processors by the numbers. Copyright held by authors/owners.

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