A minimum-energy path-preserving topology-control algorithm

The topology of a wireless multihop network can be controlled by varying the transmission power at each node. It is not energy efficient to use the communication network G_max where every node transmits with maximum power. For energy efficient operations, it is desirable to have a subnetwork that preserves a minimum-energy path between every pair of nodes (where a minimum-energy path is one that allows messages to be transmitted with a minimum use of energy). We first identify conditions that are necessary and sufficient for a subnetwork G of G_max to preserve this property. Using this characterization, we then propose an efficient topology-control algorithm that, given a communication network G_max, computes a subnetwork G that it preserves at least one minimum-energy path between every pair of nodes. We also propose an energy-efficient reconfiguration protocol that maintains this minimum-energy path property as the network topology changes dynamically. We demonstrate the performance improvements of our algorithm over other existing topology-control algorithms through simulation.