Distributed beamforming for information transfer in sensor networks

Energy efficient transfer of data from sensors is a fundamental problem in sensor networks. We propose a distributed beamforming approach to this problem, with a cluster of sensors emulating a centralized antenna array. While it is well-known that beamforming can provide large performance gains, such gains presuppose not only accurate knowledge of the channel, but also time and phase synchronization at the transmitter. We propose explicit methods for achieving such synchronization in a distributed fashion, and analyze the effects of various sources of coordination error on the attained performance. We find that, as long as the error in range measurements or placement of the sensor nodes is within a fraction of a carrier wavelength, the proposed distributed beamforming strategies achieve most of the gains available from a centralized beamformer.