Sensor placement and lifetime of wireless sensor networks: theory and performance analysis

Increasing the lifetime of energy constrained wireless sensor networks is one of the key challenges in sensor network research. In this paper we present a bottom-up approach to evaluating the lifetime performance of networks employing two basic sensor placement schemes: square-grid and hex-grid. Lifetimes of individual sensor node as well lifetimes of networks are modeled as random variables and their probability density functions (pdf) are obtained theoretically. Reliability theory is used for the network lifetime analysis, and provides a methodology for similar studies. Simulation results show that the actual pdf´s match very closely to those obtained theoretically. The theoretical results provided in this paper will serve as a basis for other related research such as analysis of other sensor placement schemes, lifetime and sensor density tradeoff study, and performance of energy efficiency related algorithms.