Large wireless sensor networks promise to revolutionize the way we sense and control the physical world. In large networks the nodes within the range of the base station forward data on behalf of the entire network. Under reasonable assumptions, as this burden significantly shortens the lifespan of these nodes, the network may become disconnected (and, hence, unusable) while considerable battery resources remain unused at the peripheral nodes. To alleviate this undesired effect, we investigate the effect of multiple battery levels to maximize the useful lifetime of the network. We demonstrate a powerful, yet attractively simple scheme to redistribute the total energy budget in multiple (but few) battery levels. We show by theoretical analysis, as well as simulation, that this substantially improves the network lifetime.
Mihail L. Sichitiu, Rudra Dutta