Analysis of the Lifetime of Large Wireless Sensor Networks

In large wireless sensor networks, nodes are required to self-organize them into a network without previously established infrastructure. Large numbers of sensor nodes are scattered throughout the area to be monitored. All data collected by the nodes is to be sent to the sink node in a multi-hop fashion. The sensors closer to the sink have to relay more messages than nodes at the periphery of the network. This burden significantly shortens the lifespan of these nodes; the network may become disconnected while considerable energy remains unused at the peripheral nodes. To alleviate this undesired effect, we investigate the energy consumption of different layers, and demonstrate a powerful simple scheme to redistribute the total energy budget in different tiers. We show by theoretical analysis, as well as simulation, that this substantially improves the network lifetime.