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Hermans, Frederik
Publications (10 of 27) Show all publications
Varshney, A., Harms, O., Pérez Penichet, C., Rohner, C., Hermans, F. & Voigt, T. (2017). LoRea: A backscatter architecture that achieves a long communication range. In: Proc. 15th ACM Conference on Embedded Network Sensor Systems: . Paper presented at SenSys 2017, November 5–8, Delft, The Netherlands. New York: ACM Press
Open this publication in new window or tab >>LoRea: A backscatter architecture that achieves a long communication range
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2017 (English)In: Proc. 15th ACM Conference on Embedded Network Sensor Systems, New York: ACM Press, 2017Conference paper, Published paper (Refereed)
Abstract [en]

There is the long-standing assumption that radio communication in the range of hundreds of meters needs to consume mWs of power at the transmitting device. In this paper, we demonstrate that this is not necessarily the case for some devices equipped with backscatter radios. We present LoRea an architecture consisting of a tag, a reader and multiple carrier generators that overcomes the power, cost and range limitations of existing systems such as Computational Radio Frequency Identification (CRFID). LoRea achieves this by: First, generating narrow-band backscatter transmissions that improve receiver sensitivity. Second, mitigating self-interference without the complex designs employed on RFID readers by keeping carrier signal and backscattered signal apart in frequency. Finally, decoupling carrier generation from the reader and using devices such as WiFi routers and sensor nodes as a source of the carrier signal. An off-the-shelf implementation of LoRea costs 70 USD, a drastic reduction in price considering commercial RFID readers cost 2000 USD. LoRea's range scales with the carrier strength, and proximity to the carrier source and achieves a maximum range of 3.4 km when the tag is located at 1m distance from a 28 dBm carrier source while consuming 70 mu W at the tag. When the tag is equidistant from the carrier source and the receiver, we can communicate upto 75m, a significant improvement over existing RFID readers.

Place, publisher, year, edition, pages
New York: ACM Press, 2017
National Category
Computer Engineering
Identifiers
urn:nbn:se:uu:diva-335566 (URN)10.1145/3131672.3131691 (DOI)000462783500018 ()978-1-4503-5459-2 (ISBN)
Conference
SenSys 2017, November 5–8, Delft, The Netherlands
Available from: 2017-11-05 Created: 2017-12-06 Last updated: 2019-08-28Bibliographically approved
Carlos, P. P., Hermans, F. & Voigt, T. (2017). On Limits of Constructive Interference in Backscatter Systems. In: Global Internet of Things Summit (GIoTS), 2017: . Paper presented at Global Internet of Things Summit (GIoTS), Geneva, Switzerland, June 06-09, 2017 (pp. 178-182). IEEE
Open this publication in new window or tab >>On Limits of Constructive Interference in Backscatter Systems
2017 (English)In: Global Internet of Things Summit (GIoTS), 2017, IEEE, 2017, p. 178-182Conference paper, Published paper (Other academic)
Abstract [en]

Backscatter communication reduces the energy consumption of resource-constrained sensors and actuators by several orders of magnitude as it avoids the resource-consuming need to generate a radio wave. Many backscatter systems and applications suffer from low communication range. By exploiting the collective power of several tags that transmit the same data simultaneously, constructive interference may help to remedy this problem and increase the communication range. When several tags backscatter the same signal simultaneously it is not necessarily true that constructive interference occurs. As our theoretical results and previous work indicate the interference might also be destructive. Our experimental results on real hardware suggest that exploiting constructive interference to increase the communication range requires careful coordination which is difficult in decentralized settings.

Place, publisher, year, edition, pages
IEEE, 2017
Keywords
Interference, Backscatter, Receivers, Radio transmitters, Radiofrequency identification
National Category
Telecommunications Communication Systems Embedded Systems
Identifiers
urn:nbn:se:uu:diva-335569 (URN)10.1109/GIOTS.2017.8016241 (DOI)000425861800032 ()978-1-5090-5873-0 (ISBN)
Conference
Global Internet of Things Summit (GIoTS), Geneva, Switzerland, June 06-09, 2017
Funder
Swedish Energy Agency
Available from: 2017-12-06 Created: 2017-12-06 Last updated: 2018-05-24Bibliographically approved
Voigt, T., Själander, M., Hermans, F., Jimborean, A., Hagersten, E., Gunningberg, P. & Kaxiras, S. (2016). Approximation: A New Paradigm also for Wireless Sensing. In: : . Paper presented at International Conference on Embedded Wireless Systems and Networks.
Open this publication in new window or tab >>Approximation: A New Paradigm also for Wireless Sensing
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2016 (English)Conference paper, Poster (with or without abstract) (Refereed)
National Category
Computer Engineering
Identifiers
urn:nbn:se:uu:diva-287456 (URN)
Conference
International Conference on Embedded Wireless Systems and Networks
Available from: 2016-04-25 Created: 2016-04-25 Last updated: 2018-01-10
Carlos, P. P., Hermans, F., Varshney, A. & Voigt, T. (2016). Augmenting IoT networks with backscatter-enabled passive sensor tags. In: Proceedings of the 3rd Workshop on Hot Topics in Wireless: . Paper presented at 3rd Workshop on Hot Topics in Wireless, HotWireless. October 3-7, 2016. New York (pp. 23-27).
Open this publication in new window or tab >>Augmenting IoT networks with backscatter-enabled passive sensor tags
2016 (English)In: Proceedings of the 3rd Workshop on Hot Topics in Wireless, 2016, p. 23-27Conference paper, Published paper (Refereed)
Abstract [en]

The sensing modalities available in an Internet-of-Things (IoT) network are usually fixed before deployment, when the operator selects a suitable IoT platform. Retrofitting a deployment with additional sensors can be cumbersome, because it requires either modifying the deployed hardware or adding new devices that then have to be maintained. In this paper, we present our vision and work towards passive sensor tags: battery-free devices that allow to augment existing IoT deployments with additional sensing capabilities without the need to modify the existing deployment. Our passive sensor tags use backscatter transmissions to communicate with the deployed network. Crucially, they do this in a way that is compatible with the deployed network's radio protocol, and without the need for additional infrastructure. We present an FPGA-based prototype of a passive sensor tag that can communicate with unmodified 802.15.4 IoT devices. Our initial experiments with the prototype support the feasibility of our approach. We also lay out the next steps towards fully realizing the vision of passive sensor tags.

Keywords
Backscatter communication, Internet of Things, Wireless
National Category
Communication Systems
Identifiers
urn:nbn:se:uu:diva-306898 (URN)10.1145/2980115.2980132 (DOI)978-1-4503-4251-3 (ISBN)
Conference
3rd Workshop on Hot Topics in Wireless, HotWireless. October 3-7, 2016. New York
Available from: 2016-11-04 Created: 2016-11-04 Last updated: 2017-01-23Bibliographically approved
Perez Penichet, C., Hermans, F., Varshney, A. & Voigt, T. (2016). Demo: Passive Sensor Tags. In: ACM (Ed.), Mobicom'16: Proceedings Of The 22Nd Annual International Conference On Mobile Computing And Networking. Paper presented at The 22Nd Annual International Conference on Mobile Computing and Networking (MobiCom), October 3-7, 2016. New York, USA (pp. 477-478).
Open this publication in new window or tab >>Demo: Passive Sensor Tags
2016 (English)In: Mobicom'16: Proceedings Of The 22Nd Annual International Conference On Mobile Computing And Networking / [ed] ACM, 2016, p. 477-478Conference paper, Poster (with or without abstract) (Refereed)
Abstract [en]

The sensing capabilities of an Internet-of-Things (IoT) network are usually fixed at deployment. Adding new sensing modalities is a cumbersome process because it requires altering the deployed hardware. We introduce passive sensor tags that allow to easily and seamlessly add new sensors to existing IoT deployments without requiring hardware modifications or additional energy sources. Passive sensor tags employ backscatter communication to generate transmissions that can be decoded by the radio transceivers present in today's IoT devices. Furthermore, unlike recent works, our approach does not require dedicated infrastructure to generate the unmodulated carrier used for backscatter communication. The demo showcases our prototype of a passive sensor tag collecting sensor data and delivering it to unmodified commodity IoT devices using passive 802.15.4 transmissions.

Keywords
Backscatter communication, Internet of Things, Wireless
National Category
Communication Systems
Identifiers
urn:nbn:se:uu:diva-306900 (URN)10.1145/2973750.2985610 (DOI)000485222100062 ()978-1-4503-4226-1 (ISBN)
Conference
The 22Nd Annual International Conference on Mobile Computing and Networking (MobiCom), October 3-7, 2016. New York, USA
Available from: 2016-11-04 Created: 2016-11-04 Last updated: 2020-01-08Bibliographically approved
Hermans, F., McNamara, L., Sörös, G., Rohner, C., Voigt, T. & Ngai, E. (2016). FOCUS: Robust visual codes for everyone. In: Proc. 14th International Conference on Mobile Systems, Applications, and Services: . Paper presented at MobiSys 2016, June 25–30, Singapore (pp. 319-332). New York: ACM Press
Open this publication in new window or tab >>FOCUS: Robust visual codes for everyone
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2016 (English)In: Proc. 14th International Conference on Mobile Systems, Applications, and Services, New York: ACM Press, 2016, p. 319-332Conference paper, Published paper (Refereed)
Place, publisher, year, edition, pages
New York: ACM Press, 2016
National Category
Communication Systems
Identifiers
urn:nbn:se:uu:diva-290373 (URN)10.1145/2906388.2906399 (DOI)978-1-4503-4269-8 (ISBN)
Conference
MobiSys 2016, June 25–30, Singapore
Available from: 2016-06-20 Created: 2016-04-29 Last updated: 2016-06-30Bibliographically approved
Iyer, V., Hermans, F. & Voigt, T. (2015). Detecting and avoiding multiple sources of interference in the 2.4 GHz spectrum. In: Wireless Sensor Networks: . Paper presented at EWSN 2015, February 9–11, Porto, Portugal (pp. 35-51). Springer
Open this publication in new window or tab >>Detecting and avoiding multiple sources of interference in the 2.4 GHz spectrum
2015 (English)In: Wireless Sensor Networks, Springer, 2015, p. 35-51Conference paper, Published paper (Refereed)
Place, publisher, year, edition, pages
Springer, 2015
Series
Lecture Notes in Computer Science, ISSN 0302-9743 ; 8965
National Category
Computer Engineering
Identifiers
urn:nbn:se:uu:diva-260975 (URN)10.1007/978-3-319-15582-1_3 (DOI)000357677300003 ()978-3-319-15581-4 (ISBN)
Conference
EWSN 2015, February 9–11, Porto, Portugal
Available from: 2015-08-28 Created: 2015-08-27 Last updated: 2018-01-11Bibliographically approved
Hermans, F., McNamara, L. & Voigt, T. (2015). Scalable Visual Codes for Embedding Digital Data in the Physical World. In: Proceedings of the 13th ACM Conference on Embedded Networked Sensor Systems: . Paper presented at 13th ACM Conference on Embedded Networked Sensor Systems (SenSys '15) (pp. 457-458). ACM
Open this publication in new window or tab >>Scalable Visual Codes for Embedding Digital Data in the Physical World
2015 (English)In: Proceedings of the 13th ACM Conference on Embedded Networked Sensor Systems, ACM, 2015, p. 457-458Conference paper, Poster (with or without abstract) (Refereed)
Abstract [en]

Visual codes, such as QR codes, offer a low-cost alternative to RF technology when digital data needs to be embedded in objects in the physical world. However, in order to support receivers with a poor visual channel, e.g. low-resolution cameras, most visual codes are designed for low data capacity and short reading distances. We present our work on Focus, a visual code that avoids earlier work's explicit trade-off between code capacity and channel quality. Rather than encoding the payload directly into individual pixels, Focus encodes the payload over a range of spatial frequencies. As a result, even a receiver with a very poor visual channel (e.g., a low-resolution camera, or a camera experiencing motion blur) can still partly decode a Focus code, because the code's low-frequency components are robust to common channel impairments. A receiver with a good channel can decode all data from the same code. In our demo, we will present a prototype of Focus for smartphones and showcase how it deals with common impairments of the visual channel.

Place, publisher, year, edition, pages
ACM: , 2015
National Category
Computer Engineering
Research subject
Computer Science with specialization in Computer Communication
Identifiers
urn:nbn:se:uu:diva-266410 (URN)10.1145/2809695.2817852 (DOI)000380612400069 ()9781450336314 (ISBN)
External cooperation:
Conference
13th ACM Conference on Embedded Networked Sensor Systems (SenSys '15)
Available from: 2015-11-09 Created: 2015-11-09 Last updated: 2018-01-10Bibliographically approved
Hermans, F., Wennerström, H., McNamara, L., Rohner, C. & Gunningberg, P. (2014). All is not lost: Understanding and exploiting packet corruption in outdoor sensor networks. In: Wireless Sensor Networks: EWSN 2014. Paper presented at 11th European Conference on Wireless Sensor Networks, Feb 17-19, 2014, Oxford, England (pp. 116-132). Springer Berlin/Heidelberg
Open this publication in new window or tab >>All is not lost: Understanding and exploiting packet corruption in outdoor sensor networks
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2014 (English)In: Wireless Sensor Networks: EWSN 2014, Springer Berlin/Heidelberg, 2014, p. 116-132Conference paper, Published paper (Refereed)
Place, publisher, year, edition, pages
Springer Berlin/Heidelberg, 2014
Series
Lecture Notes in Computer Science ; 8354
National Category
Computer Sciences Communication Systems
Identifiers
urn:nbn:se:uu:diva-211736 (URN)10.1007/978-3-319-04651-8_8 (DOI)000340395900008 ()978-3-319-04650-1 (ISBN)
Conference
11th European Conference on Wireless Sensor Networks, Feb 17-19, 2014, Oxford, England
Projects
WISENETProFuN
Available from: 2013-11-29 Created: 2013-11-29 Last updated: 2018-01-11Bibliographically approved
Hermans, F. (2014). Sensor Networks and Their Radio Environment: On Testbeds, Interference, and Broken Packets. (Doctoral dissertation). Uppsala: Acta Universitatis Upsaliensis
Open this publication in new window or tab >>Sensor Networks and Their Radio Environment: On Testbeds, Interference, and Broken Packets
2014 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Sensor networks consist of small sensing devices that collaboratively fulfill a sensing task, such as monitoring the soil in an agricultural field or measuring vital signs in a marathon runner. To avoid cumbersome and expensive cabling, nodes in a sensor network are powered by batteries and communicate wirelessly. As a consequence of the latter, a sensor network's communication is affected by its radio environment, i.e., the environment's propagation characteristics and the presence of other radio devices. This thesis addresses three issues related to the impact of the radio environment on sensor networks.

Firstly, in order to draw conclusions from experimental results, it is necessary to assess how the environment and the experiment infrastructure affect the results. We design a sensor network testbed, dubbed Sensei-UU, to be easily relocatable. By performing an experiment in different environments, a researcher can asses the environments’ impact on results. We further augment Sensei-UU with support for mobile nodes. The implemented mobility approach adds only little variance to results, and therefore enables repeatable experiments with mobility. The repeatability of experiments increases the confidence in conclusions drawn from them.

Secondly, sensor networks may experience poor communication performance due to cross-technology radio interference, especially in office and residential environments. We consider the problem of detecting and classifying the type of interference a sensor network is exposed to. We find that different sources of interference each leave a characteristic "fingerprint" on individual, corrupt 802.15.4 packets. We design and implement the SoNIC system that enables sensor nodes to classify interference using these fingerprints. SoNIC supports accurate classification in both a controlled and an uncontrolled environment.

Finally, we consider transmission errors in an outdoor sensor network. In such an environment, errors occur despite the absence of interference if the signal-to-noise ratio at a receiver is too low. We study the characteristics of corrupt packets collected from an outdoor sensor network deployment. We find that content transformation in corrupt packets follows a specific pattern, and that most corrupt packets contain only few errors. We propose that the pattern may be useful for applications that can operate on inexact data, because it reduces the uncertainty associated with a corrupt packet.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2014. p. 73
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 1171
Keywords
Sensor networks, Testbed, Mobility, Interference classification, Packet corruption
National Category
Communication Systems
Research subject
Computer Science with specialization in Computer Communication
Identifiers
urn:nbn:se:uu:diva-230769 (URN)978-91-554-9019-5 (ISBN)
Public defence
2014-10-17, Room 1311, Polacksbacken, Lägerhyddsvägen 2, Uppsala, 13:00 (English)
Opponent
Supervisors
Projects
WISENET
Funder
VINNOVA, P26628-4
Available from: 2014-09-24 Created: 2014-08-28 Last updated: 2015-01-23
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