No abstract

The theory of network coding is hardly ever used and cannot be mapped to general wireless sensor network (WSN) topologies without careful consideration of technology constraints. Severe energy constraints and low bandwidth are faced by platforms of low computational power. We show how network coding methods can be implemented with low computational power. We discuss extensive experimentation in simulation of scalability for arbitrarily large networks. It is configured according to the results from mote hardware measurements. The testbed implementation and the mote software implementation is kept completely generic. All phases, including the initialization, are implemented and work for mesh networks of any size without modification. Our work explains important considerations for applying network coding to WSNs. The gain from applying the method over ad-hoc on-demand (AODV) like routing closely approaches the optimum value of 2. Thereby WSN resource constraints are relaxed and network lifetime is prolonged.

Wireless sensor networks (WSNs) consist of wirelessly communicating nodes with an autarkic power supply for each node. Typically, the consumable energy of these nodes is very limited. Energy harvesting systems (EHSs) can be used to extend the lifetime or even enable perpetual operation of the sensor nodes. Applicable energy-aware WSN protocols and applications usually raise the complexity such that rough calculations are not sufficient any more. Simulationbased analysis is needed to cope with the complexity of hardware/software interaction and its implications.This work presents a simulation environment which enables combined simulation and performance evaluation of complete WSNs including the sensor nodes' application software, the energy harvesting enhanced hardware, the wireless network communication, and the environment of the sensor nodes.

Wireless sensor networks (WSNs) suffer from the lack of wired infrastructure. Each node needs its own power supply, e.g. batteries or energy harvesting systems (EHSs). Typically, EHSs can extend the lifetime of a sensor node or even enable perpetual operation. Due to the high variation of harvestable energy of the environment, the design of the EHSs has to be done very carefully. The design process can be enhanced by using simulation of the WSN including energy harvesting. However, a realistic simulation needs accurate data of the harvestable energy of the environment. This paper presents the concept of an onsite characterization instrument for different types of energy harvesting devices. These instruments can be connected like a WSN.Index Terms-Wireless sensor network, energy harvesting, energy harvesting device, on-site characterization.

Wireless sensor networks (WSNs) are power critical systems, because they are used in application areas without wired infrastructure. Each sensor node needs a dedicated power supply. Today's protocols and applications for WSNs are often poweraware. However, the state-of-charge (SoC) estimation of the energy storage component (e.g. rechargeable battery) influences the decisions of the power-aware software. A measurement error may cause wrong decisions which would reduce the lifetime of the network. This work presents the simulation results of the impact of an SoC measurement error on the network lifetime running a simple and an enhanced power-aware WSN application. A simulation environment written in SystemC-AMS is used, which enables the combined simulation of the sensor node's application software and its hardware. The simulation shows a reduction of the network lifetime of 3.13% caused by an erroneous measurement. However, the enhanced software is able to increase the network lifetime by 1.66%.