EBS
Energy budgeted sensor networks based on renewable energy sources
| Contact | Prof. Dr. rer. nat. Volker Turau |
| Staff | Christian Renner |
| Financing | German Research Foundation (DFG) |
Project Description
The project develops models, methods and an experimental system for energy-budgeted sensor networks with renewable energ sources, which allow for a theoretically endless lifetime in an energy neutral fashion. For this purpose the available amount of energy in the present and in the future are estimated and operations (on the nodes and in the network) only started, if the amount of energy required for them is reliably sufficient. This project makes a significant contribution to the current state of research on the subject of renewable energy sources for sensor networks ("energy harvesting").
With its perennial experience in the field of sensor networks the Institute of Telematics develops models for a hardware suitable for energy budgeting (energy inflow, energy buffer, energy sources, reference architecture). On this basis, models and algorithms for energy budgeting on single nodes and in the whole network are devised. Their practicability will be shown by using an experimental system (hardware, system libraries and example application).
EBS is funded by the German Research Foundation (DFG) for 3 years.
Publications
Christian Renner, Florian Meier and Volker Turau. Holistic Online Energy Assessment: Feasibility and Practical Application. In Proceedings of the 9th IEEE International Conference on Networked Sensing Systems (INSS'12), June 2012. Antwerp, Belgium. To be published.
@InProceedings{Telematik_RT_2012_HolisticEnergyAssessment,
author = {Christian Renner and Florian Meier and Volker Turau},
title = {Holistic Online Energy Assessment: Feasibility and Practical Application},
booktitle = {Proceedings of the 9th IEEE International Conference on Networked Sensing Systems (INSS'12)},
day = {11-14},
month = jun,
year = 2012,
location = {Antwerp, Belgium},
}
Abstract:
Combining energy harvesting with energy-aware scheduling enables perpetually operating sensor networks. The practical realization of this goal yet requires reliable and precise holistic online energy assessment. While the building blocks--assessing residual energy, predicting energy intake, and tracing energy consumption--have been studied in detail, the analysis of their interaction on a real platform has been neglected.
This paper answers the question, whether these techniques can be easily joined to give a precise and correct picture of a sensor node's energetic state and behavior.
For this purpose, we model the energy flow of a prototype energy-harvesting sensor node and evaluate the joint performance of state-of-the-art energy assessment based on a field test. We verify the system model and show the feasibility of holistic energy assessment, which tolerates small configuration errors, achievable with a combination of generic configuration and online calibration.
We also analyze the feasibility of forecasting a node's future energetic state, and find that the presented method gives sufficient results for uniformly distributed consumption profiles.
Christian Renner, Florian Meier and Volker Turau. Policies for Predictive Energy Management with Supercapacitors. In Proceedings of the 8th IEEE International Workshop on Sensor Networks and Systems for Pervasive Computing (PerSeNS'12), March 2012. Lugano, Switzerland.
@InProceedings{Telematik_RT_2012_Epol,
author = {Christian Renner and Florian Meier and Volker Turau},
title = {Policies for Predictive Energy Management with Supercapacitors},
booktitle = {Proceedings of the 8th IEEE International Workshop on Sensor Networks and Systems for Pervasive Computing (PerSeNS'12)},
day = {19-23},
month = mar,
year = 2012,
location = {Lugano, Switzerland},
}
Abstract:
This paper presents an algorithm to dynamically determine the maximum supported uniform demand for energy of sensor nodes powered by energy harvesters using supercapacitors as energy buffers. Knowledge about the maximum uniform consumption is required to adapt the sensor node's duty cycle or task schedule to achieve uniform, utility-maximizing, and depletion-safe operation. Our algorithm makes use of a supercapacitors' relationship between state-of-charge and voltage, is particularly designed to handle the non-linear system model, and is lightweight enough to run on low-power sensor node hardware. We define three energy policies, evaluate their performance using a real-world solar-harvesting trace, and analyze the influence of the supercapacitor's capacity and errors of the energy forecast.
Christian Renner and Volker Turau. Adaptive Energy-Harvest Profiling to Enhance Depletion-Safe Operation and Efficient Task Scheduling. Sustainable Computing: Informatics and Systems, 2(1):43–56, March 2012.
@Article{Telematik_RT_2012_AdaptiveSlotting,
author = {Christian Renner and Volker Turau},
title = {Adaptive Energy-Harvest Profiling to Enhance Depletion-Safe Operation and Efficient Task Scheduling},
pages = {43-56},
journal = {Sustainable Computing: Informatics and Systems},
volume = {2},
number = {1},
month = mar,
year = 2012,
issn = {2210-5379},
}
Abstract:
Forecasting the expected energy harvest enables small-sized energy-harvesting sensor nodes to schedule tasks or adapt the radio duty cycle. This ability ensures depletion-safe and efficient operation. Most energy sources exhibit cyclic patterns of intensity, e.g., the sun. These patterns show periods with unequal--low versus high and stable versus varying--energy production and heavily depend on a node's location as well as seasonal and environmental changes. Existing forecast algorithms do not exploit these patterns, but create and update forecasts at static and arbitrary points in time, the main knob being the number of updates per cycle. We present a method enabling sensor nodes to adapt to harvesting patterns at runtime. It is designed for seamlessly replacing the static scheme to improve the accuracy of a wide range of existing forecast algorithms.
In our evaluation, we show that (i) the adaptive method traces the energy pattern in real-world deployments accurately, (ii) reacts to seasonal and environmental changes, (iii) increases forecast accuracy, and (iv) reduces the number of prediction updates. These achievements enhance depletion-safe operation and efficient task scheduling with fewer recalculations and adjustments of the duty cycle. They also facilitate the exchange of harvesting forecasts for collaborative node tasks, since less information has to be shared.
Christian Renner, Florian Meier and Volker Turau. Poster Abstract: Energy Assessment in Praxis. In Adjunct Proceedings of the 9th European Conference on Wireless Sensor Networks (EWSN'12), February 2012. Trento, Italy.
@InProceedings{Telematik_RT_2012_EnergyAssessment,
author = {Christian Renner and Florian Meier and Volker Turau},
title = {Poster Abstract: Energy Assessment in Praxis},
booktitle = {Adjunct Proceedings of the 9th European Conference on Wireless Sensor Networks (EWSN'12)},
day = {15-17},
month = feb,
year = 2012,
location = {Trento, Italy},
}
Abstract:
Combining energy harvesting with energy-aware scheduling enables perpetually operating sensor networks. Practical realization yet requires precise holistic online energy assessment. The building blocks are available, but the analysis of their interaction has been neglected. To close the gap, we evaluate the joint performance of energy assessment components. Our experiments substantiate that holistic energy assessment is feasible and that small configuration errors are tolerable.
Stefan Unterschütz, Christian Renner and Volker Turau. Opportunistic, Receiver-Initiated Data-Collection Protocol. In Proceedings of the 9th European Conference on Wireless Sensor Networks (EWSN'12), February 2012. Trento, Italy.
@InProceedings{Telematik_URT_2012_Orinoco,
author = {Stefan Unterschütz and Christian Renner and Volker Turau},
title = {Opportunistic, Receiver-Initiated Data-Collection Protocol},
booktitle = {Proceedings of the 9th European Conference on Wireless Sensor Networks (EWSN'12)},
day = {15-17},
month = feb,
year = 2012,
location = {Trento, Italy},
}
Abstract:
This paper presents and evaluates ORiNoCo, a novel data-collection and event-reporting protocol for sensor networks. ORiNoCo is built upon the asynchronous duty-cycle protocol RI-MAC and breaks with the tradition of exchanging extensive neighborhood information, a cornerstone of many competing collection protocols and one of their major source of communication overhead and energy expenditure. The merit of this venture is an opportunistic, energy-efficient, latency-reducing, and self-stabilizing protocol. ORiNoCo comes at virtually no extra costs in terms of memory demand and communication overhead compared to RI-MAC. We derive theoretical boundaries for the improvements in radio efficiency, latency, and energy-consumption. ORiNoCo is verified with these findings via simulation and compared with CTP. ORiNoCo achieves lower energy-consumption while reducing end-to-end delays.
Christian Renner, Stefan Unterschütz and Volker Turau. Power Management for Wireless Sensor Networks Based on
Energy Budgets. Technical Report urn:nbn:de:gbv:830-tubdok-11065, Hamburg University of Technology, Hamburg, Germany, July 2011.
@TechReport{Renner_Unterschuetz_PowerManagement-TechReport,
author = {Christian Renner and Stefan Unterschütz and Volker Turau},
title = {Power Management for Wireless Sensor Networks Based on
Energy Budgets},
number = {urn:nbn:de:gbv:830-tubdok-11065},
institution = {Hamburg University of Technology},
address = {Hamburg, Germany},
month = jul,
year = 2011,
}
Abstract:
This paper proposes and assesses analytical tools for
large-scale
monitoring applications with wireless sensor networks
powered by
energy-harvesting supplies. We introduce the concept of an
energy
budget, the amount of energy available to a sensor node for a
given period of time. The presented tools can be utilized to
realize
distributed algorithms that determine a schedule to
perform the
monitoring task and the inherent communication.
Scheduling is based on
the energy budgets of the nodes or on
latency requirements. In this
context, we derive theoretical
results for the energy consumption of
the individual nodes plus
the latency of event-reporting. These
results are verified by
simulations and a real testbed implementation.
Christian Renner and Volker Turau. CapLibrate: Self-Calibration of an Energy Harvesting
Power Supply with Supercapacitors. In Proceedings of the GI/ITG Workshop on Energy-aware
Systems and Methods, February 2010. Hannover, Germany.
@InProceedings{Telematik_RT_2010_CapLibrate,
author = {Christian Renner and Volker Turau},
title = {CapLibrate: Self-Calibration of an Energy Harvesting
Power Supply with Supercapacitors},
booktitle = {Proceedings of the GI/ITG Workshop on Energy-aware
Systems and Methods},
day = {22-23},
month = feb,
year = 2010,
location = {Hannover, Germany},
}
Abstract:
Achieving perpetual and self-sustaining operation of
wireless sensor nodes is
an important topic of current research in the
field of energy
harvesting. Closely related to this is the employment
of energy
budgeting, i.e., effective utilization of available and
future energy
resources without pushing a node towards the hazard of
energy
depletion. Therefore, reliable prediction of node lifetime in
context
of the available energy within a given time is required. This
in turn
requires self-calibration of the sensor nodes and their energy
harvesting supply. In this paper, we explore and assess models for a
supercapacitor-based harvesting supply. The parameters of the models
are discussed and determined, so that fast, reliable, and
energy-efficient calibration becomes possible. Moreover, measurement
results for a specific hardware platform are discussed and a roadmap
for a self-calibration algorithm is presented.
Christian Renner, Jürgen Jessen and Volker Turau. Poster: Energy Estimation for Harvesting Supplies with Supercaps. In Proceedings of the Workshop on Self-Organizing
Wireless Sensor and Communication Networks, October 2009. Hamburg, Germany.
@InProceedings{Telematik_RJT_2009_EnergyEstimation,
author = {Christian Renner and Jürgen Jessen and Volker Turau},
title = {Poster: Energy Estimation for Harvesting Supplies with Supercaps},
booktitle = {Proceedings of the Workshop on Self-Organizing
Wireless Sensor and Communication Networks},
day = {8-9},
month = oct,
year = 2009,
location = {Hamburg, Germany},
}
Christoph Weyer, Christian Renner, Volker Turau and Hannes Frey. A Roadmap for Hardware and Software Support for
Developing Energy-Efficient Sensor Networks. In Proceedings of the 8th GI/ITG KuVS Fachgespräch
"Drahtlose Sensornetze" (FGSN'09), August 2009, pp. 67–70. Hamburg, Germany.
@InProceedings{Telematik_WRTF_2009_Roadmap,
author = {Christoph Weyer and Christian Renner and Volker Turau and Hannes Frey},
title = {A Roadmap for Hardware and Software Support for
Developing Energy-Efficient Sensor Networks},
booktitle = {Proceedings of the 8th GI/ITG KuVS Fachgespräch
"Drahtlose Sensornetze" (FGSN'09)},
pages = {67-70},
day = {13-14},
month = aug,
year = 2009,
location = {Hamburg, Germany},
}
Abstract:
Support for developing energy-efficient applications
for wireless sensor
networks is still scarce.
In this paper a roadmap
of a combined hardware and software approach is
presented. The main
idea is
to collect state information and trace energy consumption of
an
application running in a testbed of
real sensor nodes.
Christian Renner, Jürgen Jessen and Volker Turau. Lifetime Prediction for Supercapacitor-powered Wireless
Sensor Nodes. In Proceedings of the 8th GI/ITG KuVS Fachgespräch
"Drahtlose Sensornetze" (FGSN'09), August 2009, pp. 55–58. Hamburg, Germany.
@InProceedings{Telematik_RJT_2009_Supercap,
author = {Christian Renner and Jürgen Jessen and Volker Turau},
title = {Lifetime Prediction for Supercapacitor-powered Wireless
Sensor Nodes},
booktitle = {Proceedings of the 8th GI/ITG KuVS Fachgespräch
"Drahtlose Sensornetze" (FGSN'09)},
pages = {55-58},
day = {13-14},
month = aug,
year = 2009,
location = {Hamburg, Germany},
}
Abstract:
Energy-aware task scheduling is a novel research
direction for wireless sensor
networks. It depends on accurate
models
for lifetime prediction. In other terms, nodes must be aware of
present and future energy resources. This
paper addresses the first
step towards reaching this goal: It explores
discharging-characteristics of
supercapacitors, discusses analytical
discharging-models for lifetime prediction, and
evaluates these models
by
comparing them with real discharging curves.
Students' theses
Completed Theses
- Temperature Modeling of Energy Buffers for Wireless Sensor Nodes
- Evaluation and Comparison of Prediction Models for a Solar Energy Harvester
- Development Support for Energy-aware Debugging
- Autonomous Power-Supply Based on Solar Cells and Supercapacitors for Wireless Sensor Nodes
- Entwurf eines Hardwareadapters zur Strommessung von drahtlosen Sensorknoten