Optimal hibernation policies for energy efficient stateful operation in high-end wireless sensor nodes

This paper proposes and studies an hibernation technique and optimal hibernation policies aimed at minimizing the power consumption, while allowing stateful processing and the adoption of more powerful nodes. To this purpose the paper models the energy trade-off for hibernating the system rather than putting it in a memory-retention sleep mode between two consecutive bursts of processing. Thanks to a simplified notion of system state, the paper formally determines the optimal conditions for deciding whether to hibernate or not the system during idle periods. Hibernation policies have been implemented as a module of the operating system and results demonstrate energy savings up to 50% compared to trivial hibernation approaches. Moreover, the hibernation policy proved to be robust and stable with respect to changes of the application parameters.