Communication-Constrained Private Decentralized Online Personalized Mean Estimation
Yauhen Yakimenka, Hsuan-Yin Lin, Eirik Rosnes, Jörg Kliewer
TL;DR
This work tackles private, decentralized online mean estimation under communication constraints by integrating differential privacy with a consensus-based algorithm (Private-C-ColME). The authors prove that, under an oracle decision rule and certain connectivity/privacy conditions, collaboration yields faster convergence than fully local updates, achieving an $O(1/t)$ mean-squared error improvement that depends on the class sizes $n_a$ and DP noise $\sigma_{\mathrm{DP}}^2$. They establish convergence bounds and privacy guarantees, and validate the approach through numerical experiments over multi-class, graph-constrained networks, showing practical gains when DP noise is appropriately bounded. The proposed framework enables real-time, personalized mean estimation in online settings while preserving data privacy and respecting communication limitations, with decision rules (Bernstein-based or optimistic distance) to identify same-mean neighbors. Overall, the paper contributes a theoretically grounded, privacy-preserving, communication-aware decentralized scheme for faster online personalization. The results underscore the trade-offs between privacy, connectivity, and collaboration gains in distributed mean estimation tasks.
Abstract
We consider the problem of communication-constrained collaborative personalized mean estimation under a privacy constraint in an environment of several agents continuously receiving data according to arbitrary unknown agent-specific distributions. A consensus-based algorithm is studied under the framework of differential privacy in order to protect each agent's data. We give a theoretical convergence analysis of the proposed consensus-based algorithm for any bounded unknown distributions on the agents' data, showing that collaboration provides faster convergence than a fully local approach where agents do not share data, under an oracle decision rule and under some restrictions on the privacy level and the agents' connectivity, which illustrates the benefit of private collaboration in an online setting under a communication restriction on the agents. The theoretical faster-than-local convergence guarantee is backed up by several numerical results.
