Spatio-temporal sampling rates and energy efficiency in wireless sensor networks

A multihop network of wireless sensors can be used to gather spatio-temporal samples of a physical phenomenon and transmit these samples to a processing center. This paper addresses an important issue in the design of such networks: determining the spatio-temporal sampling rate of the network under conditions of minimum energy usage. Prior results on the design of energy-minimizing clustering algorithms and a new collision-free protocol for gathering sensor data are used to obtain analytical results that characterize the tradeoffs among sensor density, energy usage, temporal sampling rates and spatial sampling rates in wireless sensor networks. We also show that the lower bound on delay incurred in gathering data is O(k/sup 2/n) in a clustered network of n sensors with at most k hops between any sensor and its CH.