DC-Gear: Gearing Duty Cycles in Delay-Constrained Wireless Sensor Networks

Many Wireless Sensor Network (WSN) systems are deployed in unattended areas using non-rechargeable batteries. To enable sustainable operations, most WSN systems employ duty-cycling mechanisms, such as Low Power Listening (LPL). For reliable delivery of each packet with LPL, the sender has to transmit a preamble that is long enough to span over a complete sleep interval of the receiver. In this way, the sensor nodes avoid idle listening, however, at the cost of remarkably increased end-to-end delay of multi-hop packet transmissions. To address this issue, in this paper we propose a new duty-cycling mechanism called DC-Gear. DC-Gear exploits a "sleep less but save more" phenomenon, which means increasing the duty cycle in a timely and appropriate manner while minimizing the overall energy cost and satisfying the end-to-end delay constraint. We have implemented DC-Gear with TelosB motes and demonstrated its performance advantages through extensive experiments.