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  • 1. 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.

  • 2. 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.

  • 3.
    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.

  • 4.
    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.

  • 5.
    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.

  • 6. 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.

  • 7.
    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.

  • 8.
    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).
    Cho, Jeong Woo
    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).
    IoT-grid: IoT Communication for Smart DC Grids2016In: 2016 IEEE Global Communications Conference, GLOBECOM 2016 - Proceedings, Institute of Electrical and Electronics Engineers (IEEE), 2016, article id 7841917Conference paper (Refereed)
    Abstract [en]

    IoT technology is considered an essential imperative for Smart Grids (SGs). However, IoT devices have inherently limited responsiveness that may not be sufficient for a time critical SG with stringent demands on communication delay. In practice, it remains an outstanding problem to combine IoT technology with existing grids. To facilitate deployment of IoT-based grids in domestic environments, we propose IoT-grid, a programmable, small-scale, direct current (DC) grid, that can be easily implemented with low-power hardware with limited processing capacity. The proposed grid adopts relatively cheap DC-DC converters which not only provide high conversion efficiency but also accommodate existing small-scale DC power systems (e.g. solar panels). We then explore the communication aspects of IoT-grid, namely, control and monitoring functions. We observe that processing delays of IoT devices have large impact on IoT-grid, which cause a chain of control commands to take considerable longer time as the number of commands increases. To mitigate this problem, we propose a mechanism based on sending burst commands with scheduled responses. Our experimental results show that, in the presence of processing delays, this method can significantly reduce the overall response time.

  • 9.
    Tanyingyong, Voravit
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Communication Systems, CoS, Network Systems Laboratory (NS Lab).
    Olsson, Robert
    KTH, School of Electrical Engineering and Computer Science (EECS), Communication Systems, CoS, Network Systems Laboratory (NS Lab).
    Hidell, Markus
    KTH, School of Electrical Engineering and Computer Science (EECS), Communication Systems, CoS, Network Systems Laboratory (NS Lab).
    Sjödin, Peter
    KTH, School of Electrical Engineering and Computer Science (EECS), Communication Systems, CoS, Network Systems Laboratory (NS Lab).
    Ahlgren, Bengt
    RISE SICS.
    Implementation and Deployment of an Outdoor IoT-based Air Quality Monitoring Testbed2018In: 2018 IEEE Global Communications Conference, GLOBECOM 2018 - Proceedings, Institute of Electrical and Electronics Engineers (IEEE), 2018, article id 8647287Conference paper (Refereed)
    Abstract [en]

    This paper presents an outdoor IoT-based air quality monitoring testbed deployed in the city of Uppsala, Sweden. Our IoT sensing unit is designed and developed using low-cost hardware components and open source software, which makes it easy to replicate. We demonstrate that it can serve as an affordable solution for real-time measurements and has potentials to complement traditional monitoring to cover larger areas. We use low-power communication based on IEEE 802.15.4, RPL, and MQTT, and achieve high end-to-end delivery ratio (>98%) in an outdoor setting. Moreover, we carry out network analysis of our testbed and provide detailed insights into its characteristics.

  • 10.
    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.

  • 11.
    Turull, Daniel
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Sjödin, Peter
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Olsson, Robert
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Network Systems Laboratory (NS Lab).
    Pktgen: Measuring performance on high speed networks2016In: Computer Communications, ISSN 0140-3664, E-ISSN 1873-703X, Vol. 82, p. 39-48Article in journal (Refereed)
    Abstract [en]

    Abstract Pktgen is a tool for high-speed packet generation and testing. It runs in the Linux kernel, and is designed to accommodate a wide range of network performance tests. Pktgen consists of a packet generator, a receiver, and a protocol that defines the format for test packets. This paper describes the design of pktgen, and discusses its usage as a capable performance testing tool. The design is focused on performance, and in order to generate packets at high packet rate, pktgen takes advantage of multicore systems and multi-queue features on modern network cards. To support realistic heterogeneous traffic patterns, pktgen can generate multiple simultaneous UDP flows. Pktgen supports measurements of throughput, latency, packet inter-arrival time, and packet delay variation with a wide-range of fine-grained user specified rates. We evaluate and compare pktgen to other tools, and show that it is more than an order of magnitude faster than current Linux applications such as Iperf and Netperf, and has the same upper limit on performance as special-purpose high-speed tools, such as DPDK and Netmap, when it comes to throughput measurements with user-specified rate.

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