System software techniques for low-power operation in wireless sensor networks

The operation of wireless sensor networks is fundamentally constrained by available energy sources. The underlying hardware determines the power draw of each possible mode of operation. System software attempts maximize the use of the lowest possible modes of each of the subsystems. This tutorial paper describes the system software techniques used at several levels. At the application sensing level, this includes duty-cycling, sensor hierarchy, and aggregation. At the communication level, it includes low-power listening, communication scheduling, piggybacking, post-hoc synchronization, and power-aware routing. At the node OS level, it includes event driven execution with split-phase operation and cooperative power management interfaces. At the lowest level, it includes management of primary and secondary energy storage devices coupled with intelligent charge transfer scheduling. All of these aspects must be integrated in a systematic software framework.