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  • 1.
    Ahmed, Mobyen Uddin
    et al.
    Mälardalen University, Sweden.
    Fotouhi, Hossein
    Mälardalen University, Sweden.
    Köckemann, Uew
    Örebro University, Sweden.
    Lindén, Maria
    Mälardalen University, Sweden.
    Tomasic, Ivan
    Mälardalen University, Sweden.
    Tsiftes, Nicolas
    RISE - Research Institutes of Sweden, ICT, SICS.
    Voigt, Thiemo
    RISE - Research Institutes of Sweden, ICT, SICS.
    Run-Time Assurance for the E-care@home System2018In: Part of the Lecture Notes of the Institute for Computer Sciences, Social Informatics and Telecommunications Engineering book series (LNICST, volume 225), 2018, p. 107-110Conference paper (Refereed)
    Abstract [en]

    This paper presents the design and implementation of the software for a run-time assurance infrastructure in the E-care@home system. An experimental evaluation is conducted to verify that the run-time assurance infrastructure is functioning correctly, and to enable detecting performance degradation in experimental IoT network deployments within the context of E-care@home. © 2018, ICST Institute for Computer Sciences, Social Informatics and Telecommunications Engineering.

  • 2.
    Ahmed, Mobyen Uddin
    et al.
    Mälardalen University, Sweden.
    Fotouhi, Hossein
    Mälardalen University, Sweden.
    Köckemann, Uwe
    Örebro University, Sweden.
    Lindén, Maria
    Mälardalen University, Sweden.
    Tomasic, Ivan
    Mälardalen University, Sweden.
    Tsiftes, Nicolas
    RISE - Research Institutes of Sweden, ICT, SICS.
    Voigt, Thiemo
    RISE - Research Institutes of Sweden, ICT, SICS.
    Run-Time Assurance for the E-care@home System2017In: Lecture Notes of the Institute for Computer Sciences, Social-Informatics and Telecommunications Engineering, LNICST, 2017, Vol. 225, p. 107-110Conference paper (Refereed)
  • 3.
    Al Nahas, Beshr
    et al.
    RISE, Swedish ICT, SICS.
    Duquennoy, Simon
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Iyer, Venkatraman
    Voigt, Thiemo
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Low-Power Listening Goes Multi-Channel2014Conference paper (Refereed)
    Abstract [en]

    Exploiting multiple radio channels for communication has been long known as a practical way to mitigate interference in wireless settings. In Wireless Sensor Networks, however, multi-channel solutions have not reached their full potential: the MAC layers included in TinyOS or the Contiki OS for example are mostly single-channel. The literature offers a number of interesting solutions, but experimental results were often too few to build confidence. We propose a practical extension of low-power listening, MiCMAC, that performs channel hopping, operates in a distributed way, and is independent of upper layers of the protocol stack. The above properties make it easy to deploy in a variety of scenarios, without any extra configuration/scheduling/channel selection hassle. We implement our solution in Contiki and evaluate it in a 97-node testbed while running a complete, out-of-the-box low-power IPv6 communication stack (UDP/RPL/6LoWPAN). Our experimental results demonstrate increased resilience to emulated WiFi interference (e.g., data yield kept above 90% when ContikiMAC drops in the 40% range). In noiseless environments, MiCMAC keeps the overhead low in comparison to ContikiMAC, achieving performance as high as 99% data yield along with sub-percent duty cycle and sub-second latency for a 1-minute inter-packet interval data collection.

  • 4.
    Ali, Muneeb
    et al.
    RISE, Swedish ICT, SICS.
    Umar, Saif
    Dunkels, Adam
    RISE, Swedish ICT, SICS.
    Voigt, Thiemo
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Römer, Kay
    Langendoen, Koen
    Polastre, Joseph
    Uzmi, Zartash Afzal
    Medium access control issues in sensor networks2006In: Computer communication review, ISSN 0146-4833, E-ISSN 1943-5819, Vol. 36, p. 33-36Article in journal (Refereed)
    Abstract [en]

    Medium access control for wireless sensor networks has been a very active research area for the past couple of years. The sensor networks literature presents an alphabet soup of medium access control protocols with almost all of the works focusing only on energy efficiency. There is much more innovative work to be done at the MAC layer, but current efforts are not addressing the hard unsolved problems. Majority of the works appearing in the literature are "least publishable incremental improvements" over the popular S-MAC [1] protocol. In this paper we present research directions for future medium access research. We identify some open issues and discuss possible solutions.

  • 5.
    Ali, Muneeb
    et al.
    RISE, Swedish ICT, SICS.
    Voigt, Thiemo
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Uzmi, Zartash Afzal
    Mobility Management in Sensor Networks2006Conference paper (Refereed)
  • 6.
    Alirezaie, Marjan
    et al.
    Örebro University, Sweden.
    Renoux, Jennifer
    Örebro University, Sweden.
    Köckemann, Uwe
    Örebro University, Sweden.
    Kristoffersson, Annica
    Örebro University, Sweden.
    Karlsson, Lars
    Örebro University, Sweden.
    Blomqvist, Eva
    RISE - Research Institutes of Sweden, ICT, SICS.
    Tsiftes, Nicolas
    RISE - Research Institutes of Sweden, ICT, SICS.
    Voigt, Thiemo
    RISE - Research Institutes of Sweden, ICT, SICS.
    Loutfi, A
    Örebro University, Sweden.
    An ontology-based context-aware system for smart homes: E-care@home2017In: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 17, no 7, article id 1586Article in journal (Refereed)
    Abstract [en]

    Smart home environments have a significant potential to provide for long-term monitoring of users with special needs in order to promote the possibility to age at home. Such environments are typically equipped with a number of heterogeneous sensors that monitor both health and environmental parameters. This paper presents a framework called E-care@home, consisting of an IoT infrastructure, which provides information with an unambiguous, shared meaning across IoT devices, end-users, relatives, health and care professionals and organizations. We focus on integrating measurements gathered from heterogeneous sources by using ontologies in order to enable semantic interpretation of events and context awareness. Activities are deduced using an incremental answer set solver for stream reasoning. The paper demonstrates the proposed framework using an instantiation of a smart environment that is able to perform context recognition based on the activities and the events occurring in the home.

  • 7.
    Alonso, Juan
    et al.
    RISE, Swedish ICT, SICS.
    Dunkels, Adam
    RISE, Swedish ICT, SICS.
    Voigt, Thiemo
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Bounds on the energy consumption of routings in wireless sensor networks2004Conference paper (Refereed)
  • 8.
    Alonso, Juan
    et al.
    RISE - Research Institutes of Sweden, ICT, SICS.
    Dunkels, Adam
    RISE, Swedish ICT, SICS.
    Voigt, Thiemo
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Bounds on the Energy Consumption of Routings in Wireless Sensor Networks2003Report (Other academic)
    Abstract [en]

    Energy is one of the most important resources in wireless sensor networks. We use an idealized mathematical model to study the impact of routing on energy consumption. Our results are very general and, within the assumptions listed in Section 2, apply to arbitrary topologies, routings and radio energy models. We find bounds on the minimal and maximal energy routings will consume, and use them to bound the lifetime of the network. The bounds are sharp, and can be achieved in many situations of interest. We illustrate the theory with some examples.

  • 9. Alonso, Juan
    et al.
    Dunkels, Adam
    RISE, Swedish ICT, SICS.
    Voigt, Thiemo
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Bounds on the Lifetime of Wireless Sensor Networks2004Report (Other academic)
    Abstract [en]

    Energy is one of the most important resources in wireless sensor networks. We use an idealized mathematical model to study the energy consumption under all possible routings. Our results are very general and, within the assumptions listed in Section 2, apply to arbitrary topologies, routings and radio energy models. We find bounds on the minimal and maximal energy routings will consume, and use them to bound the lifetime of the network. The bounds are sharp, and we show that they are achievable in many situations of interest. We give some examples, and apply the theory to the problem of covering a given square region with the most efficient member of a family of increasingly more dense square-lattice sensor networks. Finally, we use simulations to test these results in a more realistic scenario, where packet loss can occur.

  • 10. Alonso, Juan
    et al.
    Voigt, Thiemo
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Varshney, Ambuj
    Bounds on the Lifetime of WSNs2013Conference paper (Refereed)
  • 11.
    Arıs, Ahmet
    et al.
    Istanbul Technical University, Turkey.
    Oktug, Sema F.
    Istanbul Technical University, Turkey.
    Voigt, Thiemo
    RISE - Research Institutes of Sweden, ICT, SICS.
    Security of internet of things for a reliable internet of services2018In: Part of the Lecture Notes in Computer Science book series (LNCS, volume 10768), 2018, p. 337-370Chapter in book (Refereed)
    Abstract [en]

    The Internet of Things (IoT) consists of resource-constrained devices (e.g., sensors and actuators) which form low power and lossy networks to connect to the Internet. With billions of devices deployed in various environments, IoT is one of the main building blocks of future Internet of Services (IoS). Limited power, processing, storage and radio dictate extremely efficient usage of these resources to achieve high reliability and availability in IoS. Denial of Service (DoS) and Distributed DoS (DDoS) attacks aim to misuse the resources and cause interruptions, delays, losses and degrade the offered services in IoT. DoS attacks are clearly threats for availability and reliability of IoT, and thus of IoS. For highly reliable and available IoS, such attacks have to be prevented, detected or mitigated autonomously. In this study, we propose a comprehensive investigation of Internet of Things security for reliable Internet of Services. We review the characteristics of IoT environments, cryptography-based security mechanisms and D/DoS attacks targeting IoT networks. In addition to these, we extensively analyze the intrusion detection and mitigation mechanisms proposed for IoT and evaluate them from various points of view. Lastly, we consider and discuss the open issues yet to be researched for more reliable and available IoT and IoS. © The Author(s) 2018.

  • 12. Aschenbruck, Nils
    et al.
    Ernst, Raphael
    Schwamborn, Matthias
    Österlind, Fredrik
    RISE, Swedish ICT, SICS.
    Voigt, Thiemo
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Poster Abstract: Adding Mobility to Wireless Sensor Network Simulations2010Conference paper (Refereed)
  • 13. Baccour, Nouha
    et al.
    Koubaa, Anis
    Noda, Claro
    Fotouhi, Hossein
    Alves, Mario
    Youssef, Hossein
    Zuniga, Marco
    Boano, Carlo Alberto
    Römer, Kay
    Puccinelli, Daniele
    Mottola, Luca
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Voigt, Thiemo
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Radio Link Quality Estimation in Low-Power Wireless Networks2013 (ed. 12)Book (Refereed)
  • 14. Bagci, Ibrahim Ethem
    et al.
    Pourmirza, Mohammad Reza
    Raza, Shahid
    RISE, Swedish ICT, SICS, Security Lab.
    Roedig, Utz
    Voigt, Thiemo
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Codo: Confidential Data Storage for Wireless Sensor Networkss2012Conference paper (Refereed)
    Abstract [en]

    Many Wireless Sensor Networks (WSNs) are used to collect and process confidential information. Confidentiality must be ensured at all times and, for example, solutions for confidential communication, processing or storage are required. To date, the research community has addressed mainly the issue of confidential communication. Efficient solutions for cryptographically secured communication and associated key exchange in WSNs exist. Many WSN applications, however, rely heavily on available on-node storage space and therefore it is essential to ensure the confidentiality of stored data as well. In this paper we present Codo, a confidential data storage solution which balances platform, performance and security requirements. We implement Codo for the Contiki WSN operating system and evaluate its performance.

  • 15. Bagci, Ibrahim Ethem
    et al.
    Raza, Shahid
    RISE, Swedish ICT, SICS, Security Lab.
    Chung, Tony
    Roedig, Utz
    Voigt, Thiemo
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Combined Secure Storage and Communication for the Internet of Things2013Conference paper (Refereed)
  • 16.
    Bagci, Ibrahim Ethem
    et al.
    Lancaster University, UK.
    Raza, Shahid
    RISE, Swedish ICT, SICS, Security Lab.
    Roedig, Utz
    Lancaster University, UK.
    Voigt, Thiemo
    RISE, Swedish ICT, SICS, Computer Systems Laboratory. Uppsala University, Sweden.
    Fusion: Coalesced Confidential Storage and Communication Framework for the IoT2015In: Security and Communication Networks, ISSN 1939-0114, E-ISSN 1939-0122, Vol. 9, no 15, p. 2656-2673Article in journal (Refereed)
    Abstract [en]

    Comprehensive security mechanisms are required for a successful implementation of the Internet of Things (IoT). Existing solutions focus mainly on securing the communication links between Internet hosts and IoT devices. However, as most IoT devices nowadays provide vast amounts of flash storage space it is as well required to consider storage security within a comprehensive security framework. Instead of developing independent security solutions for storage and communication we propose Fusion, a framework which provides coalesced confidential storage and communication. Fusion uses existing secure communication protocols for the IoT such as IPsec and DTLS and re-uses the defined communication security mechanisms within the storage component. Thus, trusted mechanisms developed for communication security are extended into the storage space. Notably, this mechanism allows us to transmit requested data directly from the file system without decrypting read data blocks and then re-encrypting these for transmission. Thus, Fusion provides benefits in terms of processing speed and energy efficiency which are important aspects for resource constrained IoT devices. The paper describes the Fusion architecture and its instantiation for IPsec and DTLS based systems. We describe Fusion’s implementation and evaluate its storage overheads, communication performance and energy consumption

  • 17.
    Behboodi, Arash
    et al.
    Evarilos.
    Crombez, Pieter
    Evarilos.
    de las Heras, Jose Javier
    De Poorter, Eli
    Handziski, Vlado
    Lemic, Filip
    Moerman, Ingrid
    Van Haute, Tom
    Verhoeve, Piet
    Voigt, Thiemo
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Wirström, Niklas
    RISE, Swedish ICT, SICS.
    Wolisz, Adam
    Evaluation of RF-based Indoor Localization Solutions for the Future Internet2013Conference paper (Refereed)
  • 18.
    Behboodi, Arash
    et al.
    Technical University of Berlin, Germany.
    Wirström, NIclas
    RISE, Swedish ICT, SICS.
    Lemic, Filip
    Technical University of Berlin, Germany.
    Voigt, Thiemo
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Wolisz, Adam
    RISE, Swedish ICT, SICS.
    Interference Effect on Localization Solutions: Signal Feature Perspective2015In: 2015 IEEE 81st Vehicular Technology Conference (VTC Spring), 2015, 10, article id 7145885Conference paper (Refereed)
    Abstract [en]

    We study the effect of interference on localization algorithms through the study of the interference effect on signal features that are used for localization. Particularly, the effect of interference on packet-based Received Signal Strength Indicator (RSSI), reported by IEEE 802.11 and IEEE 802.15.4 technologies, and on Time of Flight (ToF), reported by IEEE 802.15.4 technology, is studied using both theoretical discussions and experimental verifications. As for the RSSI values, using an information theoretic formulation, we distinguish three operational regimes and we show that the RSSI values, in dBm, remain unchanged in the noise-limited regime, increase almost linearly with interference power in dBm in the interference-limited regime and cannot be obtained due to packet loss in the collision regime. The maximum observable RSSI variation is dependent on the transmission rate and Signal to Noise Ratio (SNR). We also show that ToF is, interestingly, decreased under interference which is caused in the symbol synchronization procedure at the receiver. After providing the experimental results, we discuss how the localization algorithms are affected by interference.

  • 19. Boano, Carlo Alberto
    et al.
    Brown, James
    He, Zhitao
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Roedig, Utz
    Voigt, Thiemo
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Low-power radio communication in industrial outdoor deployments: the impact of weather conditions and ATEX-compliance2009Conference paper (Refereed)
  • 20. Boano, Carlo Alberto
    et al.
    He, Zhitao
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Li, Yafei
    Voigt, Thiemo
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Zuniga, Marco
    Willig, Andreas
    Controllable radio interference for experimental and testing purposes in wireless sensor networks2009Conference paper (Refereed)
  • 21. Boano, Carlo Alberto
    et al.
    Römer, Kay
    He, Zhitao
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Voigt, Thiemo
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Zuniga, Marco
    Willig, Andreas
    Demo Abstract: Generation of Controllable Radio Interference for Protocol Testing in Wireless Sensor Networks2009Conference paper (Refereed)
  • 22. Boano, Carlo Alberto
    et al.
    Römer, Kay
    Voigt, Thiemo
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Zuniga, Marco
    Poster Abstract: Agreement for Wireless Sensor Networks under External Interference2012Conference paper (Refereed)
  • 23. Boano, Carlo Alberto
    et al.
    Römer, Kay
    Österlind, Fredrik
    RISE, Swedish ICT, SICS.
    Voigt, Thiemo
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Demo Abstract: Realistic Simulation of Radio Interference in COOJA2011Conference paper (Refereed)
  • 24.
    Boano, Carlo Alberto
    et al.
    RISE, Swedish ICT, SICS.
    Tsiftes, Nicolas
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Voigt, Thiemo
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Brown, James
    Roedig, Utz
    The Impact of Temperature on Outdoor Industrial Sensornet Applications2010In: IEEE Transactions on Industrial Informatics, ISSN 1551-3203, E-ISSN 1941-0050, Vol. 6, p. 451-459Article in journal (Refereed)
  • 25. Boano, Carlo Alberto
    et al.
    Voigt, Thiemo
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Dunkels, Adam
    RISE, Swedish ICT, SICS.
    Österlind, Fredrik
    RISE, Swedish ICT, SICS.
    Tsiftes, Nicolas
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Mottola, Luca
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Suarez, Pablo
    Poster Abstract: Exploiting the LQI Variance for Rapid Channel Quality Assessment2009Conference paper (Refereed)
  • 26. Boano, Carlo Alberto
    et al.
    Voigt, Thiemo
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Noda, Claro
    Römer, Kay
    Zuniga, Marco
    JamLab: Augmenting Sensornet Testbeds with Realistic and Controlled Interference Generation2011Conference paper (Refereed)
  • 27. Boano, Carlo Alberto
    et al.
    Voigt, Thiemo
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Tsiftes, Nicolas
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Mottola, Luca
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Römer, Kay
    Zuniga, Marco
    Making Sensornet MAC Protocols Robust Against Interference2010Conference paper (Refereed)
    Abstract [en]

    Radio interference may lead to packet losses, thus negatively affecting the performance of sensornet applications. In this paper, we experimentally assess the impact of external interference on state-of-the-art sensornet MAC protocols. Our experiments illustrate that specific features of existing protocols, e.g., hand-shaking schemes preceding the actual data transmission, play a critical role in this setting. We leverage these results by identifying mechanisms to improve the robustness of existing MAC protocols under interference. These mechanisms include the use of multiple hand-shaking attempts coupled with packet trains and suitable congestion backoff schemes to better tolerate interference. We embed these mechanisms within an existing X-MAC implementation and show that they considerably improve the packet delivery rate while keeping the power consumption at a moderate level.

  • 28. Boano, Carlo Alberto
    et al.
    Wennerström, Hjalmar
    Zuniga, Marco
    Brown, James
    Keppitiyagama, Chamath
    RISE, Swedish ICT, SICS.
    Oppermann, Felix
    Roedig, Utz
    Norden, Lars-Åke
    Voigt, Thiemo
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Römer, Kay
    Hot Packets: A Systematic Evaluation of the Effect of Temperature on Low Power Wireless Transceivers2013Conference paper (Refereed)
    Abstract [en]

    Temperature is known to have a significant effect on the performance of radio transceivers: the higher the temper- ature, the lower the quality of links. Analysing this effect is particularly important in sensor networks because several applications are exposed to harsh environmental conditions. Daily or hourly changes in temperature can dramatically reduce the throughput, increase the delay, or even lead to network partitions. A few studies have quantified the impact of temperature on low-power wireless links, but only for a limited temperature range and on a single radio transceiver. Building on top of these preliminary observations, we de- sign a low-cost experimental infrastructure to vary the on- board temperature of sensor nodes in a repeatable fashion, and we study systematically the impact of temperature on various sensornet platforms. We show that temperature af- fects transmitting and receiving nodes differently, and that all platforms follow a similar trend that can be captured in a simple first-order model. This work represents an ini- tial stepping stone aimed at predicting the performance of a network considering the particular temperature profile of a given environment.

  • 29. Boano, Carlo Alberto
    et al.
    Zuniga, Marco
    Römer, Kay
    Voigt, Thiemo
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    JAG: Reliable and Predictable Wireless Agreement under External Radio Interference2012Conference paper (Refereed)
  • 30. Boano, Carlo Alberto
    et al.
    Zuniga, Marco
    Voigt, Thiemo
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Willig, Andreas
    Römer, Kay
    The Triangle Metric: Fast Link Quality Estimation for Mobile Wireless Sensor Networks (Invited Paper)2010Conference paper (Refereed)
  • 31.
    Bor, Martin
    et al.
    Lancaster University, UK.
    Roedig, Utz
    Lancaster University, UK.
    Voigt, Thiemo
    RISE, Swedish ICT, SICS, Computer Systems Laboratory. Uppsala University, Sweden.
    Alonso, Juan
    National University of Cuyo, Argentina; National University of San Luis, Argentina.
    Do LoRa Low-Power Wide-Area Networks Scale?2016In: Proceedings of the 19th ACM International Conference on Modeling, Analysis and Simulation of Wireless and Mobile Systems, 2016, p. 59-67Conference paper (Refereed)
    Abstract [en]

    New Internet of Things (IoT) technologies such as Long Range (LoRa) are emerging which enable power efficient wireless communication over very long distances. Devices typically communicate directly to a sink node which removes the need of constructing and maintaining a complex multihop network. Given the fact that a wide area is covered and that all devices communicate directly to a few sink nodes a large number of nodes have to share the communication medium. LoRa provides for this reason a range of communication options (centre frequency, spreading factor, bandwidth, coding rates) from which a transmitter can choose. Many combination settings are orthogonal and provide simultaneous collision free communications. Nevertheless, there is a limit regarding the number of transmitters a LoRa system can support. In this paper we investigate the capacity limits of LoRa networks. Using experiments we develop models describing LoRa communication behaviour. We use these models to parameterise a LoRa simulation to study scalability. Our experiments show that a typical smart city deployment can support 120 nodes per 3.8 ha, which is not sufficient for future IoT deployments. LoRa networks can scale quite well, however, if they use dynamic communication parameter selection and/or multiple sinks.

  • 32. Braun, Torsten
    et al.
    Voigt, Thiemo
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Dunkels, Adam
    RISE, Swedish ICT, SICS.
    Energy-Efficient TCP Operation in Wireless Sensor Networks2005In: PIK Journal Special Issue on Sensor Networks, ISSN 0930-5157, Vol. 28Article in journal (Refereed)
  • 33. Braun, Torsten
    et al.
    Voigt, Thiemo
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Dunkels, Adam
    RISE, Swedish ICT, SICS.
    Tcp support for sensor networks2007Conference paper (Refereed)
  • 34. Brown, James
    et al.
    McCarthy, Ben
    Roedig, Utz
    Voigt, Thiemo
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Sreenan, Cormac J.
    BurstProbe: Debugging Time-Critical Data Delivery in Wireless Sensor Networks2011Conference paper (Refereed)
    Abstract [en]

    In this paper we present BurstProbe, a new technique to accurately measure link burstiness in a wireless sensor network employed for time-critical data delivery. Measurement relies on shared probing slots that are embedded in the transmission schedule and used by nodes to assess link burstiness over time. The acquired link burstiness information can be stored in the node's ash memory and relied upon to diagnose transmission problems when missed deadlines occur. Thus, accurate diagnosis is achieved in a distributed manner and without the overhead of transmitting rich measurement data to a central collection point. For the purpose of evaluation we have implemented BurstProbe in the GinMAC WSN protocol and we are able to demonstrate it is an accurate tool to debug time-critical data delivery. In addition, we analyze the cost of implementing BurstProbe and investigate its effectiveness.

  • 35. Casati, Fabio
    et al.
    Daniel, Florian
    Dantchev, Guenadi
    Eriksson, Joakim
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Finne, Niclas
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Karnouskos, Stamatis
    Moreno Montero, Patricio
    Mottola, Luca
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Oppermann, Felix
    Picco, Gian Pietro
    Quartulli, Antonio
    Römer, Kay
    Spiess, Patrik
    Tranquillini, Stefano
    Voigt, Thiemo
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Demo Abstract: From Business Process Specifications to Sensor Network Deployments2012Conference paper (Refereed)
  • 36. Casati, Fabio
    et al.
    Daniel, Florian
    Dantchev, Guenadi
    Eriksson, Joakim
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Finne, Niclas
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Karnouskos, Stamatis
    Moreno Montero, Patricio
    Mottola, Luca
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Oppermann, Felix
    Picco, Gian Pietro
    Quartulli, Antonio
    Römer, Kay
    Spiess, Patrik
    Tranquillini, Stefano
    Voigt, Thiemo
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Towards Business Processes Orchestrating the Physical Enterprise with Wireless Sensor Networks2012Conference paper (Refereed)
  • 37. Chen, Shujuan
    et al.
    Dunkels, Adam
    RISE, Swedish ICT, SICS.
    Österlind, Fredrik
    RISE, Swedish ICT, SICS.
    Voigt, Thiemo
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Johansson, Mikael
    Time synchronization for predictable and secure data collection in wireless sensor networks2007In: Proceedings of The Sixth Annual Mediterranean Ad Hoc Networking Workshop (Med-Hoc-Net 2007), 2007, 1Conference paper (Refereed)
  • 38. Daniel, Florian
    et al.
    Eriksson, Joakim
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Finne, Niclas
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Fuchs, Harald
    Gaglione, Andrea
    Karnouskos, Stamatis
    Moreno Montero, Patricio
    Mottola, Luca
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Oertel, Nina
    Oppermann, Felix
    Picco, Gian Pietro
    Römer, Kay
    Spiess, Patrik
    Tranquillini, Stefano
    Voigt, Thiemo
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    makeSense: Real-world Business Processes through Wireless Sensor Networks2013Conference paper (Refereed)
  • 39.
    De Guglielmo, Domenico
    et al.
    University of Pisa, Italy.
    Al Nahas, Beshr
    Chalmers University of Technology, Sweden.
    Duquennoy, Simon
    RISE - Research Institutes of Sweden, ICT, SICS.
    Voigt, Thiemo
    RISE - Research Institutes of Sweden, ICT, SICS.
    Anastasi, Guiseppe
    University of Pisa, Italy.
    Analysis and Experimental Evaluation of IEEE 802.15.4e TSCH CSMA-CA Algorithm2017In: IEEE Transactions on Vehicular Technology, ISSN 0018-9545, E-ISSN 1939-9359, Vol. 66, no 2, p. 1573-1588, article id 7451274Article in journal (Refereed)
    Abstract [en]

    Time-slotted channel hopping (TSCH) is one of the medium access control (MAC) behavior modes defined in the IEEE 802.15.4e standard. It combines time-slotted access and channel hopping, thus providing predictable latency, energy efficiency, communication reliability, and high network capacity. TSCH provides both dedicated and shared links. The latter is special slots assigned to more than one transmitter, whose concurrent access is regulated by a carrier-sense multiple access with collision avoidance (CSMA-CA) algorithm. In this paper, we develop an analytical model of the TSCH CSMA-CA algorithm to predict the performance experienced by nodes when using shared links. The model allows for deriving a number of metrics, such as delivery probability, packet latency, and energy consumption of nodes. Moreover, it considers the capture effect (CE) that typically occurs in real wireless networks. We validate the model through simulation experiments and measurements in a real testbed. Our results show that the model is very accurate. Furthermore, we found that the CE plays a fundamental role as it can significantly improve the performance experienced by nodes.

  • 40. Dron, Wilfried
    et al.
    Duquennoy, Simon
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Voigt, Thiemo
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Hachicha, Khalil
    Garda, Patrick
    An Emulation-based Method for Lifetime Estimation of Wireless Sensor Networks2014Conference paper (Refereed)
    Abstract [en]

    Lifetime estimation in Wireless Sensor Networks (WSN) is crucial to ensure that the network will last long enough (low maintenance cost) while not being over-dimensioned (low initial cost). Existing solutions have at least one of the two following limitations: (1) they are based on theoretical models or high-level protocol implementations, overlooking low-level (e.g., hardware, driver, etc.) constraints which we find have a significant impact on lifetime, and (2) they use an ideal battery model which over-estimates lifetime due to its constant voltage and its inability to model the non-linear properties of real batteries. We introduce a method for WSN lifetime estimation that operates on compiled firmware images and models the complex behavior of batteries. We use the MSPSim/Cooja node emulator and network simulator to run the application in a cycle-accurate manner and log all component states. We then feed the log into our lifetime estimation framework, which models the nodes and their batteries based on both technical and experimental specifications. In a case study of a Contiki RPL/6LoWPAN application, we identify and resolve several low-level implementation issues, thereby increasing the predicted network lifetime from 134 to 484 days. We compare our battery model to the ideal battery model and to the lifetime estimation based on the radio duty cycle, and find that there is an average over-estimation of 36% and 76% respectively.

  • 41.
    Dunkels, Adam
    et al.
    RISE, Swedish ICT, SICS.
    Alonso, Juan
    RISE - Research Institutes of Sweden, ICT, SICS.
    Voigt, Thiemo
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Making TCP/IP Viable for Wireless Sensor Networks2003Report (Other academic)
    Abstract [en]

    The TCP/IP protocol suite, which has proven itself highly successful in wired networks, is often claimed to be unsuited for wireless micro-sensor networks. In this work, we question this conventional wisdom and present a number of mechanisms that are intended to enable the use of TCP/IP for wireless sensor networks: spatial IP address assignment, shared context header compression, application overlay routing, and distributed TCP caching (DTC). Sensor networks based on TCP/IP have the advantage of being able to directly communicate with an infrastructure consisting either of a wired IP network or of IP-based wireless technology such as GPRS. We have implemented parts of our mechanisms both in a simulator environment and on actual sensor nodes, and preliminary results are promising.

  • 42.
    Dunkels, Adam
    et al.
    RISE, Swedish ICT, SICS.
    Alonso, Juan
    RISE - Research Institutes of Sweden, ICT, SICS.
    Voigt, Thiemo
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Ritter, Hartmut
    Distributed TCP Caching for Wireless Sensor Networks2004Report (Other academic)
    Abstract [en]

    Previous research on transport layer protocols for wireless sensor networks (WSNs) has focused on designing protocols specifically targeted for sensor networks. Most sensor networks applications, however, are only useful when connected to an external network. The deployment of TCP/IP in WSNs would enable direct connection between the WSN and external TCP/IP networks. However, TCP performs badly in wireless environments both in terms of throughput and energy efficiency. To overcome these problems in WSNs we have designed Distributed TCP Caching. This mechanism greatly enhances TCP performance by caching TCP segments on the nodes in the sensor network and locally retransmitting lost segments. Our simulations demonstrate that with these enhancements TCP performs well enough to be useful in wireless sensor networks.

  • 43.
    Dunkels, Adam
    et al.
    RISE, Swedish ICT, SICS.
    Feeney, Laura Marie
    RISE, Swedish ICT, SICS.
    Grönvall, Björn
    RISE, Swedish ICT, SICS.
    Voigt, Thiemo
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    An integrated approach to developing sensor network solutions2004In: Proceedings of the Second International Workshop on Sensor and Actor Network Protocols and Applications, 2004, 1Conference paper (Refereed)
    Abstract [en]

    This paper describes a prototype sensor networking platform and its associated development environment. Key elements of the system are the ESB sensor hardware, the Contiki operating system, and the communication stack, which includes a MAC layer and a highly optimized TCP/IP. Because the work is driven by prototype applications being developed by project partners, particular attention is paid to the development environment and to practical deployment issues. Three prototype applications are also presented.

  • 44.
    Dunkels, Adam
    et al.
    RISE, Swedish ICT, SICS.
    Finne, Niclas
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Eriksson, Joakim
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Voigt, Thiemo
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Reprogramming wireless sensor networks with run-time dynamic linking in Contiki.2007In: Proceedings of Real-Time in Sweden 2007, 2007, 1Conference paper (Refereed)
  • 45.
    Dunkels, Adam
    et al.
    RISE, Swedish ICT, SICS.
    Finne, Niclas
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Eriksson, Joakim
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Voigt, Thiemo
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Run-time dynamic linking for reprogramming wireless sensor networks2006Conference paper (Refereed)
    Abstract [en]

    From experience with wireless sensor networks it has become apparent that dynamic reprogramming of the sensor nodes is a useful feature. The resource constraints in terms of energy, memory, and processing power make sensor network reprogramming a challenging task. Many different mechanisms for reprogramming sensor nodes have been developed ranging from full image replacement to virtual machines. We have implemented an in-situ run-time dynamic linker and loader that use the standard ELF object file format. We show that run-time dynamic linking is an effective method for reprogramming even resource constrained wireless sensor nodes. To evaluate our dynamic linking mechanism we have implemented an application-specific virtual machine and a Java virtual machine and compare the energy cost of the different linking and execution models. We measure the energy consumption and execution time overhead on real hardware to quantify the energy costs for dynamic linking. Our results suggest that while in general the overhead of a virtual machine is high, a combination of native code and virtual machine code provide good energy efficiency. Dynamic run-time linking can be used to update the native code, even in heterogeneous networks.

  • 46.
    Dunkels, Adam
    et al.
    RISE, Swedish ICT, SICS.
    Grönvall, Björn
    Voigt, Thiemo
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Contiki - a Lightweight and Flexible Operating System for Tiny Networked Sensors2004In: Proceedings of the First IEEE Workshop on Embedded Networked Sensors, 2004, 1Conference paper (Refereed)
    Abstract [en]

    Wireless sensor networks are composed of large numbers of tiny networked devices that communicate untethered. For large scale networks it is important to be able to dynamically download code into the network. In this paper we present Contiki, a lightweight operating system with support for dynamic loading and replacement of individual programs and services. Contiki is built around an event-driven kernel but provides optional preemptive multithreading that can be applied to individual processes. We show that dynamic loading and unloading is feasible in a resource constrained environment, while keeping the base system lightweight and compact.

  • 47.
    Dunkels, Adam
    et al.
    RISE, Swedish ICT, SICS.
    Grönvall, Björn
    RISE - Research Institutes of Sweden, ICT, SICS.
    Voigt, Thiemo
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Alonso, Juan
    RISE - Research Institutes of Sweden, ICT, SICS.
    The Design of a Lightweight Portable Operating System for Tiny Networked Sensor Devices2004Report (Other academic)
    Abstract [en]

    Wireless sensor networks are composed of large numbers of tiny networked devices that communicate untethered. In this paper we present the design of Contiki, a lightweight and portable operating system for such tiny devices. In this work, we try to find the right operating system abstractions that enable dynamic and efficient operation of a system with severe limitations. Contiki is built around a lightweight event scheduler and provides suitable abstractions for dynamic loading of programs, device drivers, and run-time linking of libraries. The system is highly portable and the kernel can be ported without changing a single line of code (except device drivers). We show how higher level abstractions such as multi-threading can be implemented as libraries on top of the lightweight event kernel.

  • 48.
    Dunkels, Adam
    et al.
    RISE, Swedish ICT, SICS.
    Schmidt, Oliver
    Voigt, Thiemo
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Using Protothreads for Sensor Node Programming2005In: Proceedings of the REALWSN'05 Workshop on Real-World Wireless Sensor Networks, 2005, 1Conference paper (Refereed)
    Abstract [en]

    Wireless sensor networks consist of tiny devices that usually have severe resource constraints in terms of energy, processing power and memory. In order to work efficiently within the constrained memory, many operating systems for such devices are based on an event-driven model rather than on multi-threading. While event-driven systems allow for reduced memory usage, they require programs to be developed as explicit state machines. Since implementing programs as explicit state machines is hard, developing, maintaining, and debugging programs for event-driven systems is difficult. In this paper, we introduce protothreads, a programming abstraction for event-driven sensor network systems. Protothreads simplify implementation of high-level functionality on top of event-driven systems, without significantly increasing the memory requirements. The memory requirement of a protothread is that of an unsigned integer.

  • 49.
    Dunkels, Adam
    et al.
    RISE, Swedish ICT, SICS.
    Schmidt, Oliver
    Voigt, Thiemo
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Ali, Muneeb
    Protothreads: simplifying event-driven programming of memory-constrained embedded systems2006Conference paper (Refereed)
    Abstract [en]

    Event-driven programming is a popular model for writing programs for tiny embedded systems and sensor network nodes. While event-driven programming can keep the memory overhead down, it enforces a state machine programming style which makes many programs difficult to write, maintain, and debug. We present a novel programming abstraction called protothreads that makes it possible to write event-driven programs in a thread-like style, with a memory overhead of only two bytes per protothread. We show that protothreads significantly reduce the complexity of a number of widely used programs previously written with event-driven state machines. For the examined programs the majority of the state machines could be entirely removed. In the other cases the number of states and transitions was drastically decreased. With protothreads the number of lines of code was reduced by one third. The execution time overhead of protothreads is on the order of a few processor cycles.

  • 50.
    Dunkels, Adam
    et al.
    RISE, Swedish ICT, SICS.
    Voigt, Thiemo
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Alonso, Juan
    Connecting wireless sensor networks with the internet2004In: ERCIM News, ISSN 0926-4981, E-ISSN 1564-0094, no 57Article in journal (Refereed)
12345 1 - 50 of 232
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