Anton Hergenröder

A Survey on Testbeds and Experimentation Environments for Wireless Sensor Networks

Research results in wireless sensor networks are primarily gained from simulations and theoretical considerations. Currently, the community begins to realize that the results need to be validated in testbeds. Testbeds can be also used to directly gather knowledge with sensor network experiments on real hardware and a real environmental context. This survey gives an overview of different approaches to build testbeds and experimentation environments regarding different research foci. We discuss emerging testbed requirements and present existing solutions of the community. The overview is complemented with a discussion of common design decisions concerning architectures and experimentation support in current testbeds. A look on future trends and developments in wireless sensor network testbeds concludes this paper. This survey is intended to help researchers to attain own results in real-world experiments with wireless sensor networks. The reader gains a comprehensive overview on existing testbeds and practical knowledge documented in the referenced literature. The survey is laying the foundation for design decisions while developing an own testbed using the examples of described approaches.

Distributed energy measurements in wireless sensor networks

Energy efficiency is a common requirement for most WSN applications. We present our approach utilizing precise distributed monitoring of energy consumption to support the development of energy efficient protocols. There-fore we designed dedicated energy monitoring and management hardware for a wireless sensor network testbed. In our demonstration we show distributed energy measurement in a typical sensor network application based on an area monitoring scenario.

Facing challenges in evaluation of WSN energy efficiency with distributed energy measurements

Experimental evaluations of energy efficiency in WSNs on real nodes are very reliable, but also challenging. Due to the large amount of nodes and complex communication paths energy measurements have to be done in a distributed fashion. In this paper we analyze the challenges of distributed energy measurements and propose our approach to face them with WSN testbeds. In this context, we discuss existing energy measurement approaches and energy aware testbeds.

On energy measurement methods in wireless networks

Measuring the energy consumption of a communication device is necessary in order to develop energy-aware and energy-efficient protocols and applications. There exist various approaches to determine the energy consumption of a device. This paper gives a structured overview on the state of the art of energy measurement and provides a detailed analysis of the advantages and drawbacks of each technique. An improved understanding of how energy measurement can actually be accomplished allows to choose the right measurement technique according to a particular purpose and leverages the development and improvement of energy-aware and energy-efficient protocols and applications.

Evaluating energy-efficiency of hardware-based security mechanisms

Security in Wireless Sensor Networks (WSNs) is an omnipresent topic. In many application scenarios, like the surveillance of critical areas or infrastructures, security mechanisms have to be used to build reliable and secure applications. Up to now, most of the used cryptographic algorithms have been implemented in software despite the resource constraints in terms of processing power, memory and energy. In the past few years, the usage of special hardware accelerated security modules has been proposed as a viable alternative to software implementations. However, the energy-efficiency has not yet been evaluated in-depth. In this paper, we analyze the VaultIC420 security module and present an evaluation of its energy-efficiency. We compare the performance and energy-efficiency of the hardware module to common software implementations like TinyECC. For the energy measurements, we use IRIS sensor nodes in the SANDbed testbed at the Karlsruhe Institute of Technology. Our evaluation shows, that the VaultIC420 can save up to 76% of energy using different MAC layer protocols. It also shows, that the current draw of the VaultIC420 requires a duty-cycling mechanisms to achieve any savings compared to the software implementation.

OMNeTA: A Hybrid Simulator for a Realistic Evaluation of Heterogeneous Networks

High-quality simulation tools are crucial to evaluate the energy efficiency of applications and protocols for wireless sensor networks in the most realistic way. Sensor node emulators like Avrora are well-suited for homogeneous networks but can not cope with heterogeneous networking scenarios. Wireless sensor networks have been used mostly isolated for special purposes in the past. But use cases like the so called smart environments require wireless sensor nodes to communicate and interact with other devices too. In this paper, we present OMNeTA as a solution to this problem, offering the ability to simulate highly heterogeneous networks of different device classes. Our hybrid simulation approach combines the proven hardware emulation by Avrora, radio communication simulation by \mixim and the flexibility of OMNeT++. Bridging the abstraction gap between hardware emulation and network simulation, OMNeTA may also reduce the effort required to experiment with new protocols, applications or other varying parameters, by enabling rapid-prototyping like development processes.