Upper bounds on the lifetime of sensor networks

Abstract

In this paper, we ask a fundamental question concerning the limits of energy eciency of sensor net- works - What is the upper bound on the lifetime of a sensor network that collects data from a speciÞed region using a certain number of energy-constrained nodes? The answer to this question is valuable for two main reasons. First, it allows calibration of real world data-gathering protocols and an understanding of factors that prevent these proto- cols from approaching fundamental limits. Secondly, the dependence of lifetime on factors like the region of obser- vation, the source behavior within that region, basestation location, number of nodes, radio path loss characteristics, eciency of node electronics and the energy available on a node, is exposed. This allows architects of sensor networks to focus on factors that have the greatest potential impact on network lifetime. By employing a combination of the- ory and extensive simulations of constructed networks, we show that in all data gathering scenarios presented, there exist networks which achieve lifetimes equal to or >95% of the derived bounds. Hence, depending on the scenario, our bounds are either tight or near-tight.