A Control-theoretic Approach for Duty Cycle Adaptation in Dynamic Wireless Sensor Networks

Dynamic network conditions are inevitable in wireless sensor networks (WSNs). In multihop WSN data collection scenarios, data traffic load becomes heavier closer to the data sink. Therefore, extensive research work has been devoted to duty cycle adaptation mechanisms to meet the time-varying and/or spatially non-uniform traffic loads. In this paper, we propose a new algorithm, called Control-theoretic approach for Duty Cycle Adaptation (CDCA), based on the non-beacon-enable mode of the IEEE 802.15.4 protocol. We consider a distributed controller to be run at each node which adapts its duty cycle to achieve energy efficiency and maximise packet delivery performance under variable traffic conditions. CDCA adjusts a sensor's duty cycle using a traffic estimation mechanism based on a novel concept called a virtual queue. This is determined based on the sensor's local queue length as well as explicit packet-drop indications collected from its child nodes in a multihop tree structure rooted at the network's data sink. Based on control theory, the proposed controller is analysed to derive system stability. Performance results obtained using Network Simulator 3 demonstrate that CDCA outperforms the most recent and relevant scheme by saving more energy while also significantly improving packet delivery ratio to the data sink.