Decentralized sequential change detection using physical layer fusion

TL;DR

This paper investigates decentralized sequential change detection using physical layer fusion in wireless sensor networks, proposing optimal transmission strategies and demonstrating improved detection delays and energy efficiency through simulations.

Contribution

It introduces a novel analog fusion technique with optimal transmission strategies for decentralized change detection under power and energy constraints.

Findings

Lower detection delays compared to existing schemes

Energy-constrained formulation improves energy utilization

Optimal strategies maximize Ali-Silvey distance

Abstract

The problem of decentralized sequential detection with conditionally independent observations is studied. The sensors form a star topology with a central node called fusion center as the hub. The sensors make noisy observations of a parameter that changes from an initial state to a final state at a random time where the random change time has a geometric distribution. The sensors amplify and forward the observations over a wireless Gaussian multiple access channel and operate under either a power constraint or an energy constraint. The optimal transmission strategy at each stage is shown to be the one that maximizes a certain Ali-Silvey distance between the distributions for the hypotheses before and after the change. Simulations demonstrate that the proposed analog technique has lower detection delays when compared with existing schemes. Simulations further demonstrate that the energy-constrained formulation enables better use of the total available energy than the power-constrained formulation in the change detection problem.