Compact wakeup scheduling in wireless sensor networks

In a traditional wakeup scheduling, sensor nodes start up numerous times to communicate in a period, thus consuming extra energy due to state transitions (e.g. from the sleep state to the active state). In this paper, we address a novel wakeup scheduling problem called compact wakeup scheduling, in which a node needs to wake up only once to communicate bidirectionally with all its neighbors. However, not all communication graphs have valid compact wakeup schedulings, and thus we focus on tree and grid topologies that have valid compact wakeup schedulings. We propose polynomial-time algorithms using the optimum number of time slots in a period for tree and grid topologies.