An energy-efficient approach for information transfer from distributed wireless sensor systems

We present a method for reconfiguring the communication and computational burden between a system consisting of two subsystems: a wireless ground-based sensor network, and an overhead unmanned aerial vehicle (UAV). A small subset of sensor nodes receives and aggregates information gathered by the network, and forms a distributed antenna array, concentrating the radiated transmission into a narrow beam aimed towards the UAV. We describe and analyze two alternative strategies to bring the UAV and the sensor network's beam into alignment, while minimizing the energy expended by the sensor network. The performance of the two strategies is compared in terms of probability of beam-UAV alignment as a function of time, and the expected time to alignment. We examine the performance tradeoff between the choice of strategy and parameters of the sensor network that affect power conservation