Can Inherent Communication Noise Guarantee Privacy in Distributed Cooperative Control ?

TL;DR

This paper demonstrates that inherent communication noise in multi-agent systems can be exploited to guarantee differential privacy without additional noise, while maintaining system stability and formation accuracy.

Contribution

It introduces a linear quadratic regulator framework where communication noise ensures privacy, eliminating the need for extra privacy-preserving noise.

Findings

Communication noise guarantees differential privacy without extra noise.

System maintains bounded tracking error and converges despite noise.

Privacy protection is achieved through inherent system noise, not added noise.

Abstract

This paper investigates privacy-preserving distributed cooperative control for multi-agent systems within the framework of differential privacy. In cooperative control, communication noise is inevitable and is usually regarded as a disturbance that impairs coordination. This work revisits such noise as a potential privacy-enhancing factor. A linear quadratic regulator (LQR)-based framework is proposed for agents communicating over noisy channels, \textcolor{black}{where the noise variance depends on the relative state differences between neighbouring agents.} The resulting controller achieves formation while protecting the reference signals from inference attacks. It is analytically proven that the inherent communication noise can guarantee bounded $(\epsilon,\delta)$-differential privacy without adding dedicated privacy noise, while the \textcolor{black}{system cooperative tracking error} remains bounded and convergent in both the mean-square and almost-sure sense.