Collaborative beamforming for distributed wireless ad hoc sensor networks

TLDR

In a sensor network, each node has an isotropic antenna and nodes cooperate to coherently transmit signals toward a target direction in the far field. The study analyzes the performance of collaborative beamforming using random array theory. The authors examine closed‑loop and open‑loop scenarios, analyzing how phase jitter and location estimation errors affect the average beampattern. They derive the average and distribution of the beampattern, show that directivity can approach N for N uniformly distributed nodes on a disk when sparsely spaced, and analyze the distribution of the maximum sidelobe peak.

Abstract

The performance of collaborative beamforming is analyzed using the theory of random arrays. The statistical average and distribution of the beampattern of randomly generated phased arrays is derived in the framework of wireless ad hoc sensor networks. Each sensor node is assumed to have a single isotropic antenna and nodes in the cluster collaboratively transmit the signal such that the signal in the target direction is coherently added in the far- eld region. It is shown that with N sensor nodes uniformly distributed over a disk, the directivity can approach N, provided that the nodes are located sparsely enough. The distribution of the maximum sidelobe peak is also studied. With the application to ad hoc networks in mind, two scenarios, closed-loop and open-loop, are considered. Associated with these scenarios, the effects of phase jitter and location estimation errors on the average beampattern are also analyzed.