ABSTRACTSAYALI SHRIRANG NIMKAR. Adaptive duty cycling for rechargeable wireless sensor networks. (Under the direction of DR. ASIS NASIPURI) The proposed research addresses development of an adaptive duty cycling scheme to extend the lifetime of wireless sensor networks (WSNs) that are powered by energy harvested from the environment. A key problem of such rechargeable sensor networks is that the energy resources of the nodes vary from one node to another. Moreover, the energy consumption in the sensor nodes are also unequal making their battery lives highly variable. Nodes that are highly loaded and/or have low energy, termed as critical nodes, deplete their batteries faster than the rest of the nodes in the network. We propose a cross layered MAC protocol that allows the critical nodes to adapt their duty cycle to reduce their energy consumption in comparison to other nodes in the network. We employ an utility function, based on game theory, as a decisive condition for adapting duty cycles of selected nodes and allowing them to perform low power operation. In addition, we apply load balancing to shift the data traffic from the highly loaded and energy constrained nodes to its neighbors, thereby conserving their energy further. This increases the lifetime of critical nodes, leading to increase in global network lifetime. Simulation results are presented to analyze the improvement of the lifetime of the network which is the main aim of this research.
