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  • 1. Battiti, R.
    et al.
    Lo Cigno, R.
    Sabel, M.
    Orava, Fredrik
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT. KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Pehrson, Björn
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT. KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Wireless LANs: From WarChalking to open access networks2005In: Journal on spesial topics in mobile networks and applications, ISSN 1383-469X, E-ISSN 1572-8153, Vol. 10, no 3, p. 275-287Article in journal (Refereed)
    Abstract [en]

    This work discusses the evolution of W-LANs from their current status of wireless termination of LAN services to a possible global infrastructure where the access networks become open to multiple operators and a vehicle of a win-win scenario, where both users and operators benefit from the new network architecture. The idea of Open Access Networks (OANs) can go beyond wireless HotSpots and be generalized to a generic shared access infrastructure that fosters service operators competition and drastically reduces the cost of last mile coverage. The general concept of Open Access Networks is detailed, highlighting its difference with the more traditional model of vertical integration of the access network into the global service. About the OANs development, it is shown how to support the quick and smooth evolution of the infrastructure toward a widespread and reliable communication support. Business models are discussed by mentioning the different actors, the market organization and the different organization forms. The final part of the paper is devoted to technical challenges such as access control, security, privacy, roaming, resource exploitation and service differentiation. As an example of how to tackle these problems, we discuss a pricing technique devoted to resource management and billing support. In addition we present a simulation on how the OAN concept can speed-up the deployment of broadband access in a real case.

  • 2.
    Byamukama, Maximus
    et al.
    Makerere Univ, Coll Engn Design Art & Technol, Kampala, Uganda..
    Akol, Roseline
    Makerere Univ, Coll Engn Design Art & Technol, Kampala, Uganda..
    Bakkabulindi, Geofrey
    Makerere Univ, Coll Engn Design Art & Technol, Kampala, Uganda..
    Pehrson, Björn
    KTH.
    Olsson, Robert
    KTH.
    Sansa-Otim, Julianne
    Makerere Univ, Coll Comp & Informat Sci, Kampala, Uganda..
    Energy Storage Options for Environment Monitoring Wireless Sensor Networks in Rural Africa2018In: PROCEEDINGS 2018 IEEE 12TH INTERNATIONAL CONFERENCE ON COMPATIBILITY, POWER ELECTRONICS AND POWER ENGINEERING (CPE-POWERENG 2018), Institute of Electrical and Electronics Engineers (IEEE), 2018Conference paper (Refereed)
    Abstract [en]

    This paper explores various traditional and emerging battery technologies available for deployments of automated environment monitoring devices using Wireless Sensor Networks (WSNs) in Africa and the considerations designers must take into account when implementing these systems. Environment-monitoring applications of WSNs are focusing more on reducing power consumption and optimizing data transmission and less on the constraints that their applications and deployment environments put on the energy storage device. We describe the various properties of energy storage devices and, for each, we highlight the requirements to be met for environment monitoring applications, especially in remote areas in Africa. We evaluate the performance of some of these energy storage options against the requirements using three use cases. We indicate the technologies that have shown reliability for each use case. We show that emerging battery technologies, such as Lithium Ion Capacitors are well suited for long-life low power deployments while the options for high-power deployments depend on the constraints faced by the designers, such as the power consumption of the sensor network components sand environment temperature range of the deployment environment.

  • 3. Byamukama, Maximus
    et al.
    Nannono, Janet Nakato
    Ruhinda, Kabonire
    Pehrson, Björn
    KTH.
    Nsabagwa, Mary
    Akol, Roselyn
    Olsson, Robert
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Network Systems Laboratory (NS Lab).
    Bakkabulindi, Geoffrey
    Kondela, Emmanuel
    Design Guidelines for Ultra-low Power Gateways in Environment Monitoring Wireless Sensor Networks2017In: 2017 IEEE AFRICON / [ed] Cornish, D R, Institute of Electrical and Electronics Engineers (IEEE), 2017, p. 1472-1478Conference paper (Refereed)
    Abstract [en]

    We explore techniques that can be used to reduce the power consumption of gateways in wireless sensor networks deployed in environment monitoring applications, such as Automatic Weather Stations (AWS). The challenge is the deployment of these networks in locations that are far from a consistent power source, such as a national grid. Such stations must be autonomous and power consumption must be minimized. We present test scenarios illustrating the impact of the suggested techniques. We explore hardware and software based methods of power reduction, assess the impact of each, the constraints to be expected and how to overcome them. We then provide a reference implementation of a gateway in which we integrate these techniques. We show that power consumption can be reduced by 48 - 85% when comparing best and worst case scenarios. The reference implementation we provide consumes 27mW at 3V.

  • 4. Kondela, Emmanuel
    et al.
    Nungu, Amos
    Pehrson, Bjorn
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Status of Existing Weather Observation Station Network in Tanzania and the Possibility to Automate and Densify it2015In: PROCEEDINGS OF THE 2015 12TH IEEE AFRICON INTERNATIONAL CONFERENCE - GREEN INNOVATION FOR AFRICAN RENAISSANCE (AFRICON), IEEE conference proceedings, 2015Conference paper (Refereed)
    Abstract [en]

    We present the status of the existing network of weather observation stations in Tanzania. The information collected to assess the challenges that should be addressed when planning to automate and densify this network is presented. We also recommend the possible sites to be considered in the densification process based on meteorological considerations. Furthermore, possible upstream links, necessary to make data from remote stations globally accessible via Internet, are suggested.

  • 5. Nilseng, Jessica
    et al.
    Gustafsson, Lars L.
    Nungu, Amos
    KTH, School of Information and Communication Technology (ICT). Dar Es Salaam Institute of Technology, Tanzania .
    Bastholm-Rahmner, Pia
    Mazali, Dennis
    Pehrson, Björn
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Network Systems Laboratory (NS Lab).
    Eriksen, Jaran
    KTH, School of Information and Communication Technology (ICT). Karolinska University Hospital, Sweden.
    A cross-sectional pilot study assessing needs and attitudes to implementation of Information and Communication Technology for rational use of medicines among healthcare staff in rural Tanzania2014In: BMC Medical Informatics and Decision Making, ISSN 1472-6947, E-ISSN 1472-6947, Vol. 14, no 1, p. 78-Article in journal (Refereed)
    Abstract [en]

    Background: In resource-poor countries access to essential medicines, suboptimal prescribing and use of medicines are major problems. Health workers lack updated medical information and treatment support. Information and Communication Technology (ICT) could help tackle this. The impact of ICT on health systems in resource-poor countries is likely to be significant and transform the practice of medicine just as in high-income countries. However, research for finding the best way of doing this is needed. We aimed to assess current approaches to and use of ICT among health workers in two rural districts of Tanzania in relation to the current drug distribution practices, drug stock and continuing medical information (CME), as well as assessing the feasibility of using ICT to improve ordering and use of medicines. Methods: This pilot study was conducted in 2010-2011, mapping the drug distribution chain in Tanzania, including problems and barriers. The study was conducted in Bunda and Serengeti districts, both part of the ICT4RD (ICT for rural development) project. Health workers involved in drug procurement and use at 13 health facilities were interviewed on use and knowledge of ICT, and their attitudes to its use in their daily work. They were also shown and interviewed about their thoughts on an android tablet application prototype for drug stock inventory and drug ordering, based on the Tanzanian Medical Stores Department (MSD) current paper forms. Results: The main challenge was a stable supply of essential medicines. Drug supplies were often delayed and incomplete, resulting in stock-outs. All 20 interviewed health workers used mobile phones, 8 of them Smartphones with Internet connection. The Health workers were very positive to the tablet application and saw its potential in reducing drug stock-outs. They also expressed a great need and wish for CME by distance. Conclusion: The tablet application was easily used and appreciated by health workers, and thus has the potential to save time and effort, reduce transportation costs and minimise drug stock-outs. Furthermore, the android tablet could be used to reach out with CME programs to health care workers at remote health facilities, as well as those in towns.

  • 6.
    Ntareme, Hervé
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication: Services and Infrastucture (Closed 20120101), Telecommunication Systems Laboratory, TSLab (closed 2012-01-01).
    Zennaro, Marco
    ICTP – International Centre for Theoretical Physics, Trieste, Italy.
    Pehrson, Björn
    KTH, School of Information and Communication Technology (ICT), Communication: Services and Infrastucture (Closed 20120101), Telecommunication Systems Laboratory, TSLab (closed 2012-01-01).
    Delay Tolerant Network on smartphones: Applications for communication challenged areas2011In: ExtremeCom '11 Proceedings of the 3rd Extreme Conference on Communication: The Amazon Expedition, ACM Press, 2011Conference paper (Refereed)
    Abstract [en]

    This paper discusses the Delay Tolerant Network (DTN) serviceand protocol stack and presents an implementation of it on theAndroid platform that is called "Bytewalla". It allows the use ofAndroid phones for the physical transport of data betweennetwork nodes in areas where there are no other links available, orwhere existing links need to be avoided for security reasons or incase the Internet is shut down by a government authority like ithappened in some Arab countries during the spring of 2011.The implementation of a store and forward messaging applicationand a Sentinel Surveillance health-care application (SSA) thatruns on top of Bytewalla are presented together with a few usagescenarios. Our conclusion is that the integration of DTN links inthe general IP-network architecture on mobile phone platform isfeasible and will make it easier to integrate DTN applications intocommunication-challenged areas. To our knowledge ourimplementation of the bundle protocol is the first on the Androidplatform.

  • 7.
    Nungu, Amos
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication: Services and Infrastucture, Telecommunication Systems Laboratory, TSLab.
    Brown, Terrence
    KTH, School of Industrial Engineering and Management (ITM).
    Pehrson, Björn
    KTH, School of Information and Communication Technology (ICT), Communication: Services and Infrastucture, Telecommunication Systems Laboratory, TSLab.
    Business Model for Developing World Municipal Broadband Network - A Case Study2011In: Global Information Infrastructure Symposium (GIIS), 2011, Da Nang, Vietnam: IEEE , 2011, p. 1-7Conference paper (Refereed)
    Abstract [en]

    A viable business model is key for the financial andoperational sustainability of community broadband network. Us-ing the public-private-partnership approach, stakeholder analysisand the business model canvas tool, we demonstrate a businessmodel that can guarantee financial and operational sustainabilityof community networks in rural developing regions. The businessmodel has been validated in a local broadband communicationnetwork built in rural Tanzania.

  • 8.
    Nungu, Amos
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication: Services and Infrastucture (Closed 20120101), Telecommunication Systems Laboratory, TSLab (closed 2012-01-01).
    Brown, Terrence
    KTH, School of Industrial Engineering and Management (ITM).
    Pehrson, Björn
    KTH, School of Information and Communication Technology (ICT), Communication: Services and Infrastucture (Closed 20120101), Telecommunication Systems Laboratory, TSLab (closed 2012-01-01).
    Challenges in Sustaining Municipal Broadband Networks in the Developing World2011In: E-TECHNOLOGIES AND NETWORKS FOR DEVELOPMENT, Verlag Berlin Heidelberg: Springer , 2011, Vol. 171, p. 26-40Conference paper (Refereed)
    Abstract [en]

    Municipal or community networks seem to be a constructivefirst step in the process of establishing sustainable broadband networksin areas where the demand for broadband communication services islarger than the supply. Besides meeting the acute demand, one purposeis to stimulate the market by demonstrating connectivity feasibility, toreduce the risks involved for commercial actors. One of the keys to thesustainability and scalability of such networks is a well designed andmanaged institutional framework based on the local prerequisites.In this paper, we report on our experience from the establishment ofthe Serengeti Broadband Network in Northern Tanzania. We have beenusing a public-private partnership approach to create a not-for-profitorganization to manage and operate a network first deployed as a researchand education effort. We present and discuss our approach, comparingand contrasting to other approaches found in the literature. We concludethat success requires local ownership. Thus, the institutional frameworkshould aim at creating local commitment and leadership.

  • 9.
    Nungu, Amos
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication: Services and Infrastucture (Closed 20120101), Telecommunication Systems Laboratory, TSLab (closed 2012-01-01).
    Knutsson, Björn
    Pehrson, Björn
    On Building Sustainable Broadband Networks in Rural Areas2011In: 2011 Technical Symposium at ITU Telecom World (ITU WT11), 2011, p. 135-140Conference paper (Refereed)
    Abstract [en]

    We present research on how to build sustainablebroadband networks in rural areas of developing regions. Due toan increasing political awareness of the importance of ICT fordevelopment, many such regions are now being networked. Thespecific design considerations are due to the technical and non-technical challenges found in those areas. Our research includesa pilot implementation in rural Tanzania.

  • 10.
    Nungu, Amos
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication: Services and Infrastucture, Telecommunication Systems Laboratory, TSLab.
    Nsubis, Genesis
    KTH, School of Information and Communication Technology (ICT), Communication: Services and Infrastucture, Telecommunication Systems Laboratory, TSLab.
    Pehrson, Björn
    KTH, School of Information and Communication Technology (ICT), Communication: Services and Infrastucture, Telecommunication Systems Laboratory, TSLab.
    Serengeti Broadband2008In: The 2nd ACM SIGCOMM Workshop on Networked Systems for De-veloping Regions, New York, NY, USA: ACM , 2008Conference paper (Refereed)
    Abstract [en]

    This paper presents a broadband island defined by a fibre-opticcommunication network between Bunda and Serengeti, two ruraldistricts in the Mara region in northern Tanzania. The purpose ofthe network is to facilitate creation and sharing of information atgovernment institutions. The network is also expected to createjobs and entrepreneurial activities in these under-served areas.

    The network is comprised of an optical fibre backbone and wireless local area networks operating in license-free spectrum asaccess networks. The fibre is currently terminated at three locations. VLAN-capable Ethernet switches with long rangeoptical transceivers provide backbone transmission as well as fibre access. To minimize costs, routers and servers in the networkare all based on standard PC hardware and Free Open Sourcesoftware. The infrastructure is operated under an Open Accessregime, other ways of resource sharing like virtualization at thelink; network and application layers are explored.

    Although the broadband island defined by the fibre has anarrowband VSAT connection to the Internet, the focus on theservices provided in the network is local, focusing on e-government, education, healthcare and support to local entrepreneurs.

  • 11. Nungu, Amos
    et al.
    Olsson, Robert
    KTH, School of Information and Communication Technology (ICT), Communication: Services and Infrastucture, Telecommunication Systems Laboratory, TSLab.
    Pehrson, Björn
    KTH, School of Information and Communication Technology (ICT), Communication: Services and Infrastucture, Telecommunication Systems Laboratory, TSLab.
    Design and Implementation of an Inclusive Ubiquitous Access2012In: Wireless personal communications, ISSN 0929-6212, E-ISSN 1572-834X, Vol. 67, no 1, p. 79-94Article in journal (Refereed)
    Abstract [en]

    The development towards ubiquitous network access requires innovative solutions to get remote areas included, especially rural areas of developing regions. The challenges include robustness of network components, poor or non-existent power supply and sustainable business models. We argue that large scale user-driven community networks are becoming technically viable to deploy in areas that are short of supply of telecommunication services due to little or no commercial interest. To support this claim, we discuss the design of key network elements and careful power management based on alternative energy sources and storage. We also provide a status report from ongoing field-tests regarding provisioning of broadband network services in Serengeti, Tanzania, and outline briefly our strategy to achieve sustainability. On the technical side, we first discuss an affordable, high-performance, low-effect router based on open source software and standard off-the-shelf hardware offering both copper and fibre links. Our design is capable of forwarding more than 700 kpps at 22.3 W. The power consumption is considerably less than all alternatives in our comparison. Then we discuss power management and the use of batteries and super-capacitors as backup and storage solutions.

  • 12.
    Nungu, Amos
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication: Services and Infrastucture, Telecommunication Systems Laboratory, TSLab.
    Olsson, Robert
    Pehrson, Björn
    KTH, School of Information and Communication Technology (ICT), Communication: Services and Infrastucture, Telecommunication Systems Laboratory, TSLab.
    On Powering Communication Networks in Developing Regions2011In: Computers and Communications (ISCC), 2011 IEEE Symposium on, Kerkyra, Greece: IEEE , 2011, p. 383-390Conference paper (Refereed)
    Abstract [en]

    The work behind this paper aims at demonstrat-ing innovative solutions for the establishment of sustainablecommunity broadband networks in areas where there is de-mand but no supply of broadband services. One of the majorchallenges turns out to be reliable power supply. To overcomethis challenge, we explore how to decrease the demand forpower as well as the feasibility of using alternative powersources, such as solar and wind, and alternative power storagetechnologies, such as batteries and ultra-capacitors.In this paper, we present data collected over 2 months fromthe Serengeti community network in rural Tanzania to discussthe quality of the existing power-grid and the feasibility ofusing solar and wind energy as alternative energy sources.The network backbone is based on 1Gbps Ethernet links overdark fibre while end-user connections are currently based onWiFi links.Our measurements regarding the quality of the power-gridshow up to 21 power-outages in one single day, with an averageof 2 outages per day. Some of the outages are due to plannedrationing schemes caused by insufficient power generationwhile some outages are due to poor wiring or installations.Our measurements and analysis of the feasibility of usingalternative power sources indicate wind speeds on the average2m/s and a persistent high-level insolation, making solar energythe prime candidate as an alternative source of electricity. Therelatively high cost of solar panels has to be mitigated byincreased energy efficiency of the network elements. We alsopropose power management to be included in the networkmanagement system to maximize the availability of the net-work services and decrease operational costs due to damagednetwork elements.

  • 13.
    Nungu, Amos
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication: Services and Infrastucture, Telecommunication Systems Laboratory, TSLab.
    Olsson, Robert
    KTH, School of Information and Communication Technology (ICT), Communication: Services and Infrastucture, Telecommunication Systems Laboratory, TSLab.
    Pehrson, Björn
    KTH, School of Information and Communication Technology (ICT), Communication: Services and Infrastucture, Telecommunication Systems Laboratory, TSLab.
    On the design of inclusive ubiquitous access2011In: ICUFN 2011 - 3rd International Conference on Ubiquitous and Future Networks, Dalian, China: IEEE , 2011, p. 346-352Conference paper (Refereed)
    Abstract [en]

    The development towards ubiquitous network access requires innovative solutions to get remote areas included, especially rural areas of developing regions. The challenges include robustness of network components, poor or non-existent power supply and sustainable business models. We argue that large scale user-driven community networks are becoming technically viable to deploy in areas that are short of supply of telecommunication services due to little or no commercial interest. To support this claim, we discuss the design of key network elements and careful power management based on alternative energy sources and storage. We also provide a status report from ongoing field-tests regarding provisioning of broadband network services in Serengeti, Tanzania, and outline briefly our strategy to achieve sustainability. On the technical side, we first discuss an affordable, high-performance, low-effect router based on open source software and standard off-the-shelf hardware offering both copper and fibre links. Our design is capable of forwarding more than 700kpps at 22.3W. The power consumption is considerably less than all alternatives in our comparison. Then we discuss power management and the use of batteries and super-capacitors as backup and storage solutions.

  • 14.
    Nungu, Amos
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication: Services and Infrastucture (Closed 20120101), Telecommunication Systems Laboratory, TSLab (closed 2012-01-01).
    Olsson, Robert
    KTH, School of Information and Communication Technology (ICT), Communication: Services and Infrastucture (Closed 20120101), Telecommunication Systems Laboratory, TSLab (closed 2012-01-01).
    Pehrson, Björn
    KTH, School of Information and Communication Technology (ICT), Communication: Services and Infrastucture (Closed 20120101), Telecommunication Systems Laboratory, TSLab (closed 2012-01-01).
    Short paper - On the design of affordable and green high-performance routers for community networks2010In: Proceedings of the 4th ACM Workshop on Networked Systems for Developing Regions, NSDR '10, 2010, p. 11-Conference paper (Refereed)
    Abstract [en]

    We argue that large scale user-driven community networks are becoming viable in areas without access to telecommunication services due to lack of commercial interest. We discuss the design of a key component supporting this claim: a high-performance, low-power-consuming and affordable router with fibre optic capable of forwarding 2 Gbps, 220kpps, powered by only 25W, which is between 7% and 17% of the alternatives in our comparison. The cost of the one-off prototype was below a third of the prices of comparable proprietary solutions and half of other open source alternatives. It can be reduced further in series production. Future work will include widening of bottlenecks without increasing cost and field tests in rural African settings.

  • 15. Nungu, Amos
    et al.
    Olsson, Robert
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Network Systems Laboratory (NS Lab).
    Pehrson, Björn
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Network Systems Laboratory (NS Lab).
    Kang, Jiawei
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Network Systems Laboratory (NS Lab).
    Kifetew, Daniel
    Rustamov, Alisher
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Network Systems Laboratory (NS Lab).
    Inclusive ubiquitous access - A status report2015In: 6th International Conference on e-Infrastructure and e-Services for Developing Countries, AFRICOMM 2014, Springer Publishing Company, 2015, p. 13-22Conference paper (Refereed)
    Abstract [en]

    The development towards ubiquitous network access requires innovative solutions to get remote areas included, especially rural areas of developing regions. We report on recent progress in the Serengeti Broadband Network, one of the first pilots established in the Tanzania ICT for Rural Development programme with the mission to design and validate a method to establish sustainable broadband markets in under-served areas. The challenges include ownership and leadership, sustainable business models, robustness of network components and poor or non-existent supply chains, including power supply.

  • 16.
    Nungu, Amos
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication: Services and Infrastucture, Telecommunication Systems Laboratory, TSLab.
    Pehrson, Bjöm
    KTH, School of Information and Communication Technology (ICT), Communication: Services and Infrastucture, Telecommunication Systems Laboratory, TSLab.
    Interconnection of broadband islands in developing regions2007In: 2007 3rd International Conference On Testbeds And Research Infrastructure For The Development Of Networks And Communities, 2007, p. 49-54Conference paper (Refereed)
    Abstract [en]

    We present research on how to establish sustainable broadband markets in rural areas of developing regions. Due to an increasing political awareness of the importance of ICT for development, many such regions are now being networked. Since they have little legacy to consider, there are opportunities to leapfrog and stimulate solutions tailored to future needs and public good. The specific properties of the network topologies discussed are due to the piecemeal deployment of optical fiber creating broadband islands to be connected via whatever narrowband links available. The quality of service in such networks of interconnected broadband islands can be optimized by making the broadband islands self-sustained and managing the narrowband links by clever use of bandwidth management schemes, buffering, caching, etc., tailored to the needs of the specific services and applications. Our strategy assumes an open access regulatory regime allowing sharing of communication resources, opening up for innovative business models and new value chains. It calls for new technical solutions, also considering power consumption and cost . Our research includes experimental validation, currently focusing on two pilots in rural Tanzania, having one of the most open regulatory frameworks in Sub-Saharan Africa. The paper discusses a network design and outlines experiments underway in the pilots.

  • 17.
    Olsson, Robert
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Network Systems Laboratory (NS Lab).
    Pehrson, Björn
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Powering devices using ultra-capacitor batteries2015In: PROCEEDINGS OF THE 2015 12TH IEEE AFRICON INTERNATIONAL CONFERENCE - GREEN INNOVATION FOR AFRICAN RENAISSANCE (AFRICON), IEEE conference proceedings, 2015Conference paper (Refereed)
    Abstract [en]

    We explore the use of ultra-capacitors as backup storage for solar powered electronic devices. We discuss two use cases: routers in off-grid broadband networks consuming a few Watt and wireless sensor network nodes using a few mW when operating and a few mu W in quiescent mode. We have been testing batteries with ultra-capacitor based cells, both EDLC and LIC, in the range from 40 to 3000F. We found them viable alternatives in some applications and started long term field tests to sort out some unclear aspects regarding maximum discharge levels. Besides the traditional function of a backup battery storage in low-power applications, the very low internal resistance of capacitors make them useful also in hybrid solutions to accommodate transient needs for high currents that traditional batteries cannot deliver. Due to the low resistance, charging/discharging can be very fast. We also show how a very simple design requiring only one LIC capacitor can power a WSN mote sending at 1 packet/minute for 6 weeks on a single charge.

  • 18.
    Tanyingyong, Voravit
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Network Systems Laboratory (NS Lab).
    Olsson, Robert
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Network Systems Laboratory (NS Lab).
    Hidell, Markus
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Network Systems Laboratory (NS Lab).
    Sjödin, Peter
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Network Systems Laboratory (NS Lab).
    Pehrson, Björn
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Network Systems Laboratory (NS Lab).
    Design and Implementation of an IoT-controlled DC-DC Converter2013In: 2013 Sustainable Internet and ICT for Sustainability, SustainIT 2013, IEEE , 2013, p. 6685199-Conference paper (Refereed)
    Abstract [en]

    In line with the shift towards renewable energy, small-scale solar panels have become commonly available. Solar panels are intermittent energy sources producing direct current, and DC-DC converters are needed to convert between different voltage levels, both for different power loads and for storing energy. DC-DC converters typically have a very limited functionality and are statically configured for specific voltage levels. In this paper, we propose a new generation of flexible DC-DC converters with software and communication support (through Contiki and CoAP) for remote power monitoring and control. We present a prototype design and implementation of a DC-DC converter including a microprocessor, a lean operating system, and networking support. With such a DC-DC converter, controlled over the Internet, we can address various types of power and energy related issues and advance the state-of-the-art of green networked applications.

  • 19.
    Tanyingyong, Voravit
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Network Systems Laboratory (NS Lab).
    Rathore, M. Siraj
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Network Systems Laboratory (NS Lab).
    Hidell, Markus
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Network Systems Laboratory (NS Lab).
    Sjödin, Peter
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Network Systems Laboratory (NS Lab).
    Pehrson, Björn
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Network Systems Laboratory (NS Lab).
    Jonsson, Sven
    Karolinska University Hospital.
    Groth, Kristina
    KTH, School of Computer Science and Communication (CSC), Media Technology and Interaction Design, MID.
    Carenet: An Infrastructure for Home-Based Healthcare Services2013In: Medicinteknikdagarna 2013, 2013Conference paper (Refereed)
  • 20.
    Zamaere, Bruce
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication: Services and Infrastucture (Closed 20120101), Telecommunication Systems Laboratory, TSLab (closed 2012-01-01).
    Sjödin, Peter
    KTH, School of Information and Communication Technology (ICT), Communication: Services and Infrastucture (Closed 20120101), Telecommunication Systems Laboratory, TSLab (closed 2012-01-01).
    Pehrson, Björn
    KTH, School of Information and Communication Technology (ICT), Communication: Services and Infrastucture (Closed 20120101), Telecommunication Systems Laboratory, TSLab (closed 2012-01-01).
    The CareNet residential gateway: A conceptual overview2010In: 2010 IEEE International Symposium on "A World of Wireless, Mobile and Multimedia Networks", WoWMoM 2010 - Digital Proceedings, IEEE , 2010, p. 5534980-Conference paper (Refereed)
    Abstract [en]

    This paper presents a high-level overview of the CareNet Home Extension Project that aims to provide support for home-based healthcare for the elderly and outpatients. Details of a home networking environment based on a virtualized Residential Gateway (RG) are provided. The RG architecture is modular and scalable supporting the dynamic provision of third party services. This accommodates multiple independent stakeholders representing healthcare providers, Internet Services Providers (ISPs), and home automation system builders among others. Interoperability is guaranteed through adherence to open standards. Initial mechanisms facilitating the integration and consolidation of in-home systems, whilst providing a flexible framework for autonomous management, are described. This addresses issues of management and configuration of complex environments by individuals with little or no technical expertise. Finally, details of an initial implementation, in terms of architectural descriptions and enabling technological components, are outlined.

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