A lifetime-aware single-session flow routing algorithm for energy-constrained wireless sensor networks

Wireless sensor networks are becoming increasingly important in recent years due to their ability to detect and convey real-time in-situ scenes for many civil and military applications. A major technical challenge for a wireless sensor network lies in the energy constraint at battery-powered nodes, which poses a fundamental limit on the network lifetime. We consider two-tiered wireless sensor networks and address the network lifetime problem for upper-tier aggregation and forwarding nodes (AFNs). Prior efforts have formulated the network lifetime problem into a linear programming (LP) problem that results in a multi-session flow routing solution. Under multi-session flow routing, each AFN must be equipped with multiple transmitters to reach various destinations at the same time, which poses scalability problem in practice. In this paper, we present SEES (for "smart energy exploitation and sharing"), which is a single-session flow routing solution (requiring only a single pair of transmitter/receiver at each AFN). SEES seeks to maximize network lifetime through energy sharing among the AFNs and following the max-min concept. Simulation results show that the SEES algorithm, albeit employing single-session flow routing, can match closely the maximum network lifetime performance obtained by an optimal multi-session flow routing solution.