Distributed duty cycle control for delay improvement in wireless sensor networks

Dynamically adjusting the time duration of a node to stay active in one data collection period, i.e., duty cycle, is an efficient strategy to save energy and prolong the lifetime of network. In this paper, we propose a novel Adaptation Duty Cycle Control (ADCC) scheme based on feedback signals for wireless sensor networks (WSNs) which can reduce to-sink data transmission delay while lifetime is also improved. In ADCC, every node adaptively adjusts its duty cycle by comparing its own energy consumption with the largest energy consumption of the entire packet delivery flow, which is stored in a feedback ACK packet generated by sink node. Since in WSNs, a huge number of sensor nodes in the area far from the sink node have much remaining energy when network dies, even up to 90 %, these nodes have much larger duty cycles in ADCC compared with previous schemes, therefore the data transmission delay can be reduced to a great extent. Additionally, ADCC provides a largest-energy notification mechanism in order to determine the appropriate duty cycle of nodes in each data collection flow according to the application-dependent requirements. Comparing with the Wake on Idle, Dual-QCon and the Same Duty Cycle (SDC) schemes, ADCC can reduce the delay by more than 59.5 % under the same network lifetime, or increase the lifetime by 32.8 %–63.4 % under the same delay requirements, while also increase energy efficiency as much as 43.1 %.