Edinburgh Napier University

  In Wireless Sensor Networks (WSNs) the use of Mobile Sink Nodes (MSNs) has been proposed in order to negate the ”hotspot” issue. This where nodes closest to the sink node shall run out of energy fastest, affecting network lifetime. However, in using an MSN there remains the issue of nodes that sink passes closest to using most energy. In this study we propose a novel Mobility Aware Duty Cycling Algorithm (MADCAL), for use at the MAC layer. This algorithm provides a lightweight solution, utilising knowledge of the mobility pattern of the sink node in order to determine a dynamic communication threshold, within which static nodes shall awaken to communicate with the sink. This avoids the need for energy-heavy beacon messages. Using the Omnet++ simulation framework and tested on a lightweight implementation of a Carrier-sense multiple access (CSMA) based MAC protocol, we demonstrate a reduction in energy consumption up to 15% and up to 300% increase in frame delivery to the MSN, when compared to the existing duty cycling approach.