Ensure Differential Privacy and Convergence Accuracy in Consensus Tracking and Aggregative Games with Coupling Constraints
Yongqiang Wang
TL;DR
The paper tackles fully distributed generalized Nash equilibrium (GNE) seeking with shared coupling constraints under differential privacy (DP). It co-designs the GNE mechanism with a DP-noise injection scheme to guarantee both provable convergence to the GNE and $\epsilon$-DP, even as iterations grow unbounded, and introduces a robust DP consensus-tracking algorithm to support accurate tracking under persistent DP-noise. The core theoretical contribution is a convergence result for stochastically-perturbed nonstationary fixed-point iterations, enabling analysis of the proposed algorithms under diminishing stepsizes while preserving privacy budgets. The methodology is validated through simulations on a Nash-Cournot game, showing that the proposed DP-GNE seeking algorithm outperforms existing DP approaches in accuracy while maintaining rigorous privacy guarantees. The work advances privacy-preserving distributed optimization by accommodating coupling constraints and providing finite cumulative privacy budgets on infinite horizons, with implications for privacy-aware resource-sharing and networked decision-making.
Abstract
We address differential privacy for fully distributed aggregative games with shared coupling constraints. By co-designing the generalized Nash equilibrium (GNE) seeking mechanism and the differential-privacy noise injection mechanism, we propose the first GNE seeking algorithm that can ensure both provable convergence to the GNE and rigorous epsilon-differential privacy, even with the number of iterations tending to infinity. As a basis of the co-design, we also propose a new consensus-tracking algorithm that can achieve rigorous epsilon-differential privacy while maintaining accurate tracking performance, which, to our knowledge, has not been achieved before. To facilitate the convergence analysis, we also establish a general convergence result for stochastically-perturbed nonstationary fixed-point iteration processes, which lie at the core of numerous optimization and variational problems. Numerical simulation results confirm the effectiveness of the proposed approach.
