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.