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Rensfelt, Olof
Publications (10 of 21) Show all publications
Wennerström, H., Hermans, F., Rensfelt, O., Rohner, C. & Nordén, L.-Å. (2013). A long-term study of correlations between meteorological conditions and 802.15.4 link performance. In: Proc. 10th International Conference on Sensing, Communications, and Networking: . Paper presented at SECON 2013 (pp. 221-229). IEEE Communications Society
Open this publication in new window or tab >>A long-term study of correlations between meteorological conditions and 802.15.4 link performance
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2013 (English)In: Proc. 10th International Conference on Sensing, Communications, and Networking, IEEE Communications Society, 2013, p. 221-229Conference paper, Published paper (Refereed)
Place, publisher, year, edition, pages
IEEE Communications Society, 2013
National Category
Computer Sciences Communication Systems
Identifiers
urn:nbn:se:uu:diva-200165 (URN)10.1109/SAHCN.2013.6644981 (DOI)978-1-4799-0230-9 (ISBN)
Conference
SECON 2013
Projects
CNDSWISENET
Available from: 2013-05-21 Created: 2013-05-21 Last updated: 2018-01-11Bibliographically approved
Hermans, F., Rensfelt, O., Voigt, T., Ngai, E., Nordén, L.-Å. & Gunningberg, P. (2013). SoNIC: Classifying interference in 802.15.4 sensor networks. In: Proc. 12th International Conference on Information Processing in Sensor Networks: . Paper presented at IPSN 2013 (pp. 55-66). New York: ACM Press
Open this publication in new window or tab >>SoNIC: Classifying interference in 802.15.4 sensor networks
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2013 (English)In: Proc. 12th International Conference on Information Processing in Sensor Networks, New York: ACM Press, 2013, p. 55-66Conference paper, Published paper (Refereed)
Place, publisher, year, edition, pages
New York: ACM Press, 2013
National Category
Computer Systems
Research subject
Computer Science with specialization in Computer Communication
Identifiers
urn:nbn:se:uu:diva-198284 (URN)10.1145/2461381.2461392 (DOI)978-1-4503-1959-1 (ISBN)
Conference
IPSN 2013
Projects
WISENETProFuN
Funder
Vinnova
Available from: 2013-04-11 Created: 2013-04-11 Last updated: 2014-09-25Bibliographically approved
Hermans, F., Rensfelt, O., Larzon, L.-Å. & Gunningberg, P. (2012). A Lightweight Approach to Online Detection and Classification of Interference in 802.15.4-based Sensor Networks. Paper presented at 3rd International Workshop on Networks of Cooperating Objects (CONET 2012). ACM SIGBED Review, 9(3), 11-20
Open this publication in new window or tab >>A Lightweight Approach to Online Detection and Classification of Interference in 802.15.4-based Sensor Networks
2012 (English)In: ACM SIGBED Review, ISSN 1551-3688, Vol. 9, no 3, p. 11-20Article in journal (Refereed) Published
Abstract [en]

With a rapidly increasing number of devices sharing access to the 2.4 GHz ISM band, interference becomes a serious problem for 802.15.4-based, low-power sensor networks. Consequently, interference mitigation strategies are becoming commonplace. In this paper, we consider the step that precedes interference mitigation: interference detection. We have performed extensive measurements to characterize how different types of interferers affect individual 802.15.4 packets. From these measurements, we define a set of features which we use to train a neural network to classify the source of interference of a corrupted packet. Our approach is sufficiently lightweight for online use in a resource constrained sensor network. It does not require additional hardware, nor does it use active spectrum sensing or probing packets. Instead, all information about interferers is gathered from inspecting corrupted packets that are received during the sensor network’s regular operation. Even without considering a history of earlier packets, our approach reaches a mean classification accuracy of 79.8%, with per interferer accuracies of64.9% for WiFi, 82.6% for Bluetooth, 72.1% for microwave ovens, and 99.6% for packets that are corrupted due to insufficient signal strength.

National Category
Computer Engineering Communication Systems
Identifiers
urn:nbn:se:uu:diva-179803 (URN)10.1145/2367580.2367582 (DOI)
Conference
3rd International Workshop on Networks of Cooperating Objects (CONET 2012)
Projects
WISENET
Available from: 2012-08-23 Created: 2012-08-23 Last updated: 2018-01-12Bibliographically approved
Wennerström, H., Hermans, F., Rensfelt, O., Rohner, C. & Nordén, L.-Å. (2012). A Long-Term Study on the Effects of Meteorological Conditions on 802.15.4 Links. In: 8th Swedish National Computer Networking Workshop, Stockholm, June 7-8. Paper presented at SNCNW 2012.
Open this publication in new window or tab >>A Long-Term Study on the Effects of Meteorological Conditions on 802.15.4 Links
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2012 (English)In: 8th Swedish National Computer Networking Workshop, Stockholm, June 7-8, 2012Conference paper, Published paper (Refereed)
Abstract [en]

Remote monitoring of natural phenomena using wireless sensor networks requires these networks to successfully operate while being exposed to the surrounding environment. Weather conditions are an essential aspect of the environment, therefore it is important to understand the effects of weather on sensor networks. This understanding is especially important since weather varies strongly over time and affects the communication between sensor nodes. In our ongoing work we study how different meteorological conditions influence radio links in outdoor wireless sensor networks that use IEEE 802.15.4 for communication. We deploy an experimental setup next to a meteorological research station and aim to run experiments over several months in order to capture both short- and long-term changes in the link characteristics. We show some initial measurements of the deployment, highlighting influences on packet reception rate and signal strength.

National Category
Communication Systems
Research subject
Computer Science with specialization in Computer Communication
Identifiers
urn:nbn:se:uu:diva-184624 (URN)
Conference
SNCNW 2012
Projects
CNDSWISENET
Available from: 2012-11-12 Created: 2012-11-12 Last updated: 2018-06-05
Hassanzadeh, N., Voigt, T., Landsiedel, O., Hermans, F. & Rensfelt, O. (2012). Do Sensor Networks need Mobile MAC Protocols. In: Proc. of Third International Workshop on Networks of Cooperating Objects (CONET 2012), held in conjunction with IPSN 2012, April 2012, Beijing, China.. Paper presented at Third International Workshop on Networks of Cooperating Objects (CONET 2012), held in conjunction with IPSN 2012, April 2012, Beijing, China..
Open this publication in new window or tab >>Do Sensor Networks need Mobile MAC Protocols
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2012 (English)In: Proc. of Third International Workshop on Networks of Cooperating Objects (CONET 2012), held in conjunction with IPSN 2012, April 2012, Beijing, China., 2012Conference paper, Published paper (Refereed)
National Category
Communication Systems
Identifiers
urn:nbn:se:uu:diva-184666 (URN)
Conference
Third International Workshop on Networks of Cooperating Objects (CONET 2012), held in conjunction with IPSN 2012, April 2012, Beijing, China.
Projects
WISENET
Available from: 2012-11-12 Created: 2012-11-12 Last updated: 2018-06-04
Hassanzadeh, N., Landsiedel, O., Hermans, F., Rensfelt, O. & Voigt, T. (2012). Efficient Mobile Data Collection with Mobile Collect. In: Proceedings of the 8th IEEE International Conference on Distributed Computing in Sensor Systems (DCOSS): . Paper presented at 8th IEEE International Conference on Distributed Computing in Sensor Systems (DCOSS) (pp. 25-32). IEEE Computer Society
Open this publication in new window or tab >>Efficient Mobile Data Collection with Mobile Collect
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2012 (English)In: Proceedings of the 8th IEEE International Conference on Distributed Computing in Sensor Systems (DCOSS), IEEE Computer Society, 2012, p. 25-32Conference paper, Published paper (Refereed)
Abstract [en]

The main task of most deployed wireless sensor networks is data collection. While a number of solutions have been designed for static networks, there are currently no widely used data collection algorithms for mobilesensor networks. In this paper, we concentrate on scenarios where many nodes, both data sources and sinks, move along a certain track in one direction, a scenario that is common in sports events. Rather than designing a new protocol from scratch, we extend an existing data collection protocol with lightweight mechanisms to make it efficient for mobility. Our extensive simulations and results in a test bed that includes mobile robots demonstrate that our solution is able to achieve high packet delivery rates at low energy consumption. For our target scenario, our solution more than doubles packet delivery rates when the network is sparse. Our solution also works well in scenarios with a higher degree of mobility where nodes move according to a more demanding random waypoint model.

Place, publisher, year, edition, pages
IEEE Computer Society, 2012
National Category
Communication Systems
Identifiers
urn:nbn:se:uu:diva-184625 (URN)10.1109/DCOSS.2012.12 (DOI)
Conference
8th IEEE International Conference on Distributed Computing in Sensor Systems (DCOSS)
Projects
WISENET
Available from: 2012-11-12 Created: 2012-11-12 Last updated: 2018-06-04
Rensfelt, O. (2012). Experimental Challenges in Wireless Sensor Networks — Environment, Mobility, and Interference. (Doctoral dissertation). Uppsala: Acta Universitatis Upsaliensis
Open this publication in new window or tab >>Experimental Challenges in Wireless Sensor Networks — Environment, Mobility, and Interference
2012 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Wireless sensor networks are used to collect sensor data in different applications such as environmental monitoring, smart building control, and health care applications. Wireless sensor nodes used are typically small, low-cost, and battery powered. The nodes are often hard to access after deployment, for example when they are in remote  locations. Another property of wireless sensor networks is that their operation is dependent on the environment they operate in, both due to the specific sensor readings but also due to the effects on communication by factors such as fading and radio interference. This makes it important to evaluate a wireless sensor network in its intendent target environment before final deployment.

To enable experiments with wireless sensor networks in their target environment, we have designed and implemented a testbed called Sensei-UU. It is designed to allow WSN experiments to be repeated in different locations, thus exposing effects caused by the environment. To allow this, the testbed is designed to be easily moved between experimental sites.

One type of WSN applications Sensei-UU is aimed to evaluate is protocols where nodes are mobile. Mobile testbed nodes are low-cost robots which follow a tape track on the floor. The localization accuracy of the robot approach is evaluated and is accurate enough to expose a protocol to fading phenoma in a repeatable manner.

Sensei-UU has helped us develop a lightweight interference classification approach, SoNIC, which runs on standard motes. The approach only use information from a standard cc2420 chipset available when packets are received. We believe that the classification accuracy is good enough to motivate specific transmission techniques avoiding interference.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2012. p. 156
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 965
Keywords
Wireless Sensor Networks, Testbed, Mobility, Interference classification
National Category
Computer Sciences Communication Systems
Research subject
Computer Science with specialization in Computer Communication
Identifiers
urn:nbn:se:uu:diva-179807 (URN)978-91-554-8448-4 (ISBN)
Public defence
2012-10-12, Polhemsalen, Ångströmlaboratoriet, Lägerhyddsvägen 1, Uppsala, 13:15 (English)
Opponent
Supervisors
Projects
WISENET
Funder
Vinnova, P26628-4
Available from: 2012-09-20 Created: 2012-08-23 Last updated: 2018-01-12
Rensfelt, O., Hermans, F., Voigt, T., Ngai, E., Nordén, L.-Å. & Gunningberg, P. (2012). SoNIC: Classifying and Surviving Interference in 802.15.4-based Sensor Networks.
Open this publication in new window or tab >>SoNIC: Classifying and Surviving Interference in 802.15.4-based Sensor Networks
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2012 (English)Report (Other academic)
Series
Technical report / Department of Information Technology, Uppsala University, ISSN 1404-3203 ; 2012-022
National Category
Computer Engineering
Identifiers
urn:nbn:se:uu:diva-179804 (URN)
Projects
WISENET
Available from: 2012-08-23 Created: 2012-08-23 Last updated: 2018-01-12Bibliographically approved
Rensfelt, O., Hermans, F., Gunningberg, P., Larzon, L.-Å. & Björnemo, E. (2011). Repeatable experiments with mobile nodes in a relocatable WSN testbed. Computer journal, 54(12), 1973-1986
Open this publication in new window or tab >>Repeatable experiments with mobile nodes in a relocatable WSN testbed
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2011 (English)In: Computer journal, ISSN 0010-4620, E-ISSN 1460-2067, Vol. 54, no 12, p. 1973-1986Article in journal (Refereed) Published
Abstract [en]

Many sensor network application scenarios include mobile nodes, such as a moving sink. Evaluatingsuch applications in a testbed is challenging since the testbed has to support mobile nodes. Wepresent Sensei-UU, a sensor network testbed that supports mobile sensor nodes. The testbedis inexpensive, relocatable and possible to reproduce by other researchers. Its primary designobjectives are to support experiments with repeatable mobility and to support relocating thetestbed deployment to different locations. Mobile sensor nodes are carried by robots that usefloor markings for navigation and localization. The testbed can be used to evaluate applicationsin which sensor nodes move in the order of meters rather than millimeters, e.g., when a humancarries a mobile phone that collects data while passing stationary sensor nodes. To investigate therepeatability of robot movements, we measure the achieved precision and timing of the robots, andfind that our robot localization is accurate to ±1 cm. Furthermore, we investigate variations inradio signal strengths between mobile and stationary nodes. We study the impact of imprecisemovements, external sources of interference, and environmental influences. We conclude thatSensei-UU supports experiments in which these variations are acceptably low to capture small-scalefading phenomena in IEEE 802.15.4.

National Category
Computer Engineering Signal Processing
Research subject
Computer Science with specialization in Computer Communication; Electrical Engineering with specialization in Signal Processing
Identifiers
urn:nbn:se:uu:diva-151814 (URN)10.1093/comjnl/bxr052 (DOI)000298386300005 ()
Projects
WISENETProFuN
Available from: 2011-04-18 Created: 2011-04-18 Last updated: 2018-01-12Bibliographically approved
Hermans, F., Rensfelt, O., Gunningberg, P., Larzon, L.-Å. & Ngai, E. (2011). Sensei-UU — a relocatable WSN testbed supporting repeatable node mobility. In: Testbeds and Research Infrastructures: Development of Networks and Communities (pp. 612-614). Berlin: Springer-Verlag
Open this publication in new window or tab >>Sensei-UU — a relocatable WSN testbed supporting repeatable node mobility
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2011 (English)In: Testbeds and Research Infrastructures: Development of Networks and Communities, Berlin: Springer-Verlag , 2011, p. 612-614Conference paper, Published paper (Refereed)
Place, publisher, year, edition, pages
Berlin: Springer-Verlag, 2011
Series
Lecture Notes of the Institute for Computer Sciences, Social Informatics and Telecommunications Engineering ; 46
National Category
Computer Engineering Communication Systems
Research subject
Computer Science with specialization in Computer Communication
Identifiers
urn:nbn:se:uu:diva-136355 (URN)10.1007/978-3-642-17851-1_57 (DOI)978-3-642-17850-4 (ISBN)
Projects
WISENET
Available from: 2010-12-02 Created: 2010-12-11 Last updated: 2018-01-12Bibliographically approved
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