Neutral Operation of the Minimum Energy Node in energy-harvesting environments

Abstract

With the recent emergence of energy-harvesting technologies in wireless devices, new challenges have to be addressed by Machine-to-Machine (M2M) communication protocols. The Neutral Operation problem is a relevant problem that seeks to maintain the energy reserve of a node in a level that minimizes energy depletion and maximizes the usage of the harvested-energy. However, neutral operation in a multihop network is a more complex issue, since the nodes lack full knowledge of the network and the nodes have diverse harvesting and consumption profiles. A simplification of the Neutral Operation problem is proposed, named Neutral Operation of the Minimum Energy Node, in which the node with the lowest amount of energy determines the operation of the whole network. This paper proposes a battery-aware solution, called Routing and Aggregation for Minimum Energy (RAME), that performs data-aggregation on the traffic load according to the minimum energy reserve on the path. As part the proposed solution, a kinetic battery model has been developed to provide non-linear battery level estimation. Besides, the Routing Protocol for Low-Power and Lossy Networks (RPL) was enhanced to use the kinetic battery estimation as metric for parent node selection and to find periodically the minimum energy reserve on the available paths. The performance evaluation of the proposed mechanism using Contiki shows the benefits of RAME in comparison to the M2M standard protocols.