Federated Offline Policy Optimization with Dual Regularization
Sheng Yue, Zerui Qin, Xingyuan Hua, Yongheng Deng, Ju Ren
TL;DR
This work tackles offline federated reinforcement learning by addressing two-tier distribution shifts that arise when learning from decentralized, static data. It introduces DRPO, a doubly regularized offline FRL algorithm that constrains local updates with respect to both the local behavioral policy and the globally aggregated policy, while using a conservative, off-policy Q-estimation mechanism. The authors prove strict policy-improvement guarantees and provide bounds that relate empirical and true MDP performance, demonstrating that proper balancing of the two regularizers yields reliable improvement. Empirically, DRPO outperforms baselines on standard offline RL benchmarks, with fast convergence and favorable communication efficiency, and ablations confirm the necessity of both regularizers. These results suggest DRPO as a practical and theoretically grounded approach for data-private, safety-sensitive distributed RL applications.
Abstract
Federated Reinforcement Learning (FRL) has been deemed as a promising solution for intelligent decision-making in the era of Artificial Internet of Things. However, existing FRL approaches often entail repeated interactions with the environment during local updating, which can be prohibitively expensive or even infeasible in many real-world domains. To overcome this challenge, this paper proposes a novel offline federated policy optimization algorithm, named $\texttt{DRPO}$, which enables distributed agents to collaboratively learn a decision policy only from private and static data without further environmental interactions. $\texttt{DRPO}$ leverages dual regularization, incorporating both the local behavioral policy and the global aggregated policy, to judiciously cope with the intrinsic two-tier distributional shifts in offline FRL. Theoretical analysis characterizes the impact of the dual regularization on performance, demonstrating that by achieving the right balance thereof, $\texttt{DRPO}$ can effectively counteract distributional shifts and ensure strict policy improvement in each federative learning round. Extensive experiments validate the significant performance gains of $\texttt{DRPO}$ over baseline methods.
