IENCE C • •S T S E C Small world for dynamic wireless cyber-physical N O H I N systems S O I V Dissertation L • O S 142 G T Y H • R Industries and consumer markets are today increasingly using G I E L VTT SCIEN CE S H E G services exposed from wireless sensor and actuator networks, A I R H C cyber-physical machine-to-machine systems. The motivation for H the research arises from problems detected in the remote 1 4 2 interaction with embedded devices over dynamic wireless networks in such systems. The selected approach is based on the application of the small- world paradigm to cyber-physical systems. It is here assumed that the concept of small world, "six degrees of separation", can be expanded to also cover communication with wireless embedded devices in cyber-physical systems context. The main contributions are the technical enablers referred to as dynamic communication spaces, dynamic M2M service spaces, configuration and remote use of services, communication overlay, access systems selection, integrated mobility, secure ad hoc networking, situated opportunistic communication, hierarchical networking for small-world networks, and short-cuts for network optimization. The enablers have been evaluated as separate technical methods and means by means of experiments and/or simulations. According to the evaluations, the enablers seem to work well as separate building blocks and that they can be combined to expand the concept of small world to also cover communication with embedded devices. Wireless short-cuts can improve the scalability and efficiency of dynamic wireless networking and weak links are essential in the neighbour discovery process. In sum, the provided enablers help the remote interaction with embedded devices and promote the application of the small-world concept to dynamic wireless cyber-physical systems. Small world for dynamic ISBN 978-951-38-8477-2 (Soft back ed.) wireless cyber-physical ISBN 978-951-38-8476-5 (URL: http://www.vttresearch.com/impact/publications) S m all w orld forISSN-L dyna 2242-119X mic wireless cyber-physical syste m s systems ISSN 2242-119X (Print) ISSN 2242-1203 (Online) http://urn.fi/URN:ISBN:978-951-38-8476-5 Juhani Latvakoski VTT SCIENCE 142 Small world for dynamic wireless cyber-physical systems ikoa L nahuJ i aL t ksokav i yt lucaF eht fo tnessa eht ht iw detneserp eb ot noi tat ress id cimedacA id ress tat noi ot eb detneserp iw ht eht tnessa fo eht lucaF yt yt i srevinU eht fo gni reenignE laci r tcelE dna ygolonhceT noi tamrofnI fo tamrofnI noi ygolonhceT dna tcelE r laci reenignE gni fo eht srevinU i yt ,aamnanniL , )2L muirot idua( i lasnuuniaK ni ecnefed ci lbup rof uluO fo uluO rof lbup ci ecnefed ni lasnuuniaK i idua( muirot )2L , ,aamnanniL .noon 21 ta ,6102 rebmeceD ts1 eht no eht ts1 rebmeceD ,6102 ta 21 .noon University of Oulu, Graduate School Faculty of Information Technology and Electrical Engineering Biomimetics and Intelligent Systems Group Infotech Oulu ISBN 978-951-38-8477-2 (Soft back ed.) ISBN 978-951-38-8476-5 (URL: http://www.vttresearch.com/impact/publications) VTT Science 142 ISSN-L 2242-119X ISSN 2242-119X (Print) ISSN 2242-1203 (Online) http://urn.fi/URN:ISBN:978-951-38-8476-5 Copyright © VTT 2016 JULKAISIJA – UTGIVARE – PUBLISHER Teknologian tutkimuskeskus VTT Oy PL 1000 (Tekniikantie 4 A, Espoo) 02044 VTT Puh. 020 722 111, faksi 020 722 7001 Teknologiska forskningscentralen VTT Ab PB 1000 (Teknikvägen 4 A, Esbo) FI-02044 VTT Tfn +358 20 722 111, telefax +358 20 722 7001 VTT Technical Research Centre of Finland Ltd P.O. Box 1000 (Tekniikantie 4 A, Espoo) FI-02044 VTT, Finland Tel. +358 20 722 111, fax +358 20 722 7001 Juvenes Print, Tampere 2016 Preface The work towards this thesis has been carried out during the years from circa 1999 to 2014 in several steps within the VTT Technical Research Centre of Finland. It is obvious that such a long period of time has not only covered working on this thesis, but the time period has also contained multiple parallel challenges and efforts that have required a fair share of my mental energy. However, a number of these “side efforts” have yielded ideas that have had a major impact on the contents of this thesis. For example, the ITEA Mobi project in the early 2000s was a very useful exercise in mobilizing the Internet. From the research projects Auto, Sonet and Conet, I learnt a lot about the technologies related to mobile ad hoc and self-organizing systems (2001–2006). International research projects under the ITEA/Artemis frameworks (2006–), such as Usenet, A2Nets, IoE and M2MGrids (ongoing), were essential in terms of understanding the dimensions of research, R&D, industrial impact and innovations, and especially the wide range of technologies related Machine-to-Machine and Cyber-Physical systems, e.g., from perspectives of applications, information, services, networking, and radio technologies with multiple business stakeholders from different domains. The EU FET Bionets project was essential for discovering the links for self- organization out of the computer science box. The parallel projects and research team leadership have been essential in terms of learning organization dynamics and understanding the importance of social links and networking between people on a global scale – it’s a small world with weak links I would say. The exercise carried out concerning the establishment of the spin-off company (Splitstreem, later Envault Corp) was essential for learning the multiple aspects of entrepreneurship and especially operating with intellectual properties within the security domain, which has also been an important technical action area in this doctoral thesis process. Today, the impact of these projects, processes and efforts can be seen in a crystallized form in this doctoral thesis publication. There are several people that have had an essential impact on the process of this work. I would particularly like to thank the supervisor of this thesis, Dr Tech, Professor Juha Röning for asking me several times during the last 10 years “why you never do a doctoral thesis”? Thank you, Juha, for your excellent encouragement and guidance during the writing process of this thesis! In addition, this work would have never happened without the support from Dr Jussi Paakkari, Dr Mikko Sallinen, Dr Tuomo Tuikka, Dr Tua Huomo and especially Mr Hannu Honka, thank you for making this work possible. During the process, the work was influenced by many discussions with multiple colleagues, e.g. Mr Johann Moreels, Dr Mahdi Ben Alaya, Mr Pertti Puolakanaho, Mr Herve Ganem, Mr Janne Göös, Mr Niclas Granqvist, Dr Taavi Hirvonen, Mr Hannu Lohi, Mr Heikki Rantanen, Mr Jyrki Huusko, Dr Arto Peterzens and a number of other important persons, which I probably remember tomorrow. Thank you all for the positive research collaborations and valuable discussions! In addition, there are a number of people, such as Pekka Pääkkönen, Pekka Välitalo, Tommi Aapaoja, Teemu Väisänen, Miika Vahtola, Arto Lappalainen, Timo Aarnipuro, Jyri Toivonen, Tero Riipinen, Kalle Määttä, Antti Iivari, Tomi Hautakoski and Jouni Heikkinen who have contributed to some projects referred to 1 above with some experiments and simulations related to the scope of this thesis. Thank you all for the excellent work! The evaluation process of the thesis produced several good proposals and recommendations for improvements. I would like to thank Professor Tullio Salmon Cinotti from the University of Bologna and Professor Dr Andreas Timm-Giel from the University of Hamburg for their willingness to consume their valuable time for pre-examining the thesis and making the evaluation. However, the most essential basis for all the efforts for this thesis were established a long time ago by my parents, Maire and Veikko, who succeeded to create a positive attitude towards education and a “never give up” attitude into my head. During the period of and efforts for this thesis work, the most important element has been the positive co-living, mental support and patience from my wife Marita, thank you! In addition, I would like to thank all our children for arranging me with some other things to do, which have been essential for learning high sensitivity to weak signals, flexibility and adaptiveness. In fact, these lessons have been very essential in leading international research collaboration projects with multiple industrial and research organizations. So, thank you all! Oulu, 9th November 2016 Juhani Latvakoski 2 Academic dissertation Supervisor Prof. Dr Tech. Juha Röning University of Oulu Oulu, Finland Reviewers Prof. Dr Andreas Timm-Giel Technical University of Hamburg Institute of Communication Networks Hamburg, Germany Prof. Dr Tullio Salmon Cinotti University of Bologna Bologna, Italy Opponent Research Associate Prof. Dr Vincenzo Mancuso IMDEA Networks Institute Madrid, Spain 3 List of publications This thesis is based on the following original publications, which are referred in the text as I–X. The publications have been reproduced with kind permission from the publishers in the latter part of this thesis book. The contribution of the author has been clarified in Section 1.2 of the thesis. I Latvakoski, J., Pakkala, D., Pääkkönen, P. A Communication Architecture for Spontaneous Systems. IEEE Wireless Communications, June 2004, Vol. 11, Issue 3, pp. 36–42. Special Issue on Migration toward 4G Wireless Communications II Latvakoski, J., Hautakoski, T., Väisänen, T., Toivonen, J., Lappalainen, A., Aarnipuro, T. Secure M2M Service Space in Residential Home. The Fourth International Conference on COMmunication System softWAre and middleware. 15–19 June 2009, Trinity College Dublin, Ireland. 8 p. III Latvakoski, J., Pääkkönen, P. Remote Interaction with Networked Appliances attached in a Mobile Personal Area Network. IEEE International Conference on Communications, ICC '03.