Transmission range control during autonomous node selection for wireless sensor networks

The operation of an effective wireless sensor network requires energy awareness. This paper focuses on the development of the autonomous node selection (ANS) algorithm as a means to conserve energy. The algorithm provides a protocol for a resource manager to conserve energy as a network of bearings-only sensors track a target in a decentralized manner. Specifically, each node within radio range of the active nodes uses the predicted target location to determine whether or not to actively measure and communicate bearing reports. The goal of ANS is to conserve energy by limiting communications while optimizing the geolocation performance of the tracker. Using derived bounds on the usefulness of nodes, the ANS method also conserves energy by limiting the transmission distance on the radios of the active nodes. As a result, nodes too far from the target to be useful can remain in a sleep mode. Once the target moves close enough to these nodes, they will receive transmissions from the active nodes and decide whether or not to actively sense and communicate. Simulations demonstrate the tradeoffs between geolocation performance and energy conservation when implementing different parameterizations of the ANS algorithm.