Optimal Schedules for Sensor Network Queries

We examine optimal strategies for querying a sensor network when energy efficiency and data freshness need to be balanced. We use statistical information about the nature of events monitored by the sensor network to develop good query schedules. For Poisson event arrivals, we develop an optimal scheduling strategy that is actually a periodic querying policy. For hyper exponential distribution of event inter-arrival times, we discuss an optimal policy, and suggest sub optimal schemes because of the high computational cost imposed by the optimal scheme. We treat the sensor network like a black box that has (primarily energy) costs associated with various operations and suggest that this is indeed feasible, as a consequence the higher-level policies that we discuss for scheduling queries can be realized easily.