Incentivized Communication for Federated Bandits

Zhepei Wei, Chuanhao Li, Haifeng Xu, Hongning Wang

Keywords: contextual bandit, federated learning, incentive mechanism

TL;DR: We introduce a novel incentivized communication problem for federated bandits, where the server must incentivize clients to share data; The proposed solution Inc-FedUCB enjoys near-optimal regret, with guarantees on communication and incentive costs.

Abstract: Most existing works on federated bandits take it for granted that all clients are altruistic about sharing their data with the server for the collective good whenever needed. Despite their compelling theoretical guarantee on performance and communication efficiency, this assumption is overly idealistic and oftentimes violated in practice, especially when the algorithm is operated over self-interested clients, who are reluctant to share data without explicit benefits. Negligence of such self-interested behaviors can significantly affect the learning efficiency and even the practical operability of federated bandit learning. In light of this, we aim to spark new insights into this under-explored research area by formally introducing an incentivized communication problem for federated bandits, where the server shall motivate clients to share data by providing incentives. Without loss of generality, we instantiate this bandit problem with the contextual linear setting and propose the first incentivized communication protocol, namely, Inc-FedUCB, that achieves near-optimal regret with provable communication and incentive cost guarantees. Extensive empirical experiments on both synthetic and real-world datasets further validate the effectiveness of the proposed method across various environments.

Submission Number: 14100