Personalized Over-the-Air Federated Learning with Personalized Reconfigurable Intelligent Surfaces
Jiayu Mao, Aylin Yener
TL;DR
This work introduces PROAR-PFed, the first personalized over-the-air federated learning framework that equips each client with a personal RIS to address non-i.i.d. data in time-varying wireless channels. It adopts a bi-level, multi-task objective combining local personalization and global learning, and solves a cross-layer optimization problem that jointly designs transmit power, local iterations, and RIS phase shifts under imperfect CSI. The authors provide convergence analysis for non-convex objectives and demonstrate, on Fashion-MNIST, that PROAR-PFed achieves superior personalized and global accuracy compared with state-of-the-art methods, particularly as data heterogeneity increases. The results highlight the practical value of per-user RIS and dynamic resource allocation for efficient and effective OTA-FL in next-generation wireless networks.
Abstract
Over-the-air federated learning (OTA-FL) provides bandwidth-efficient learning by leveraging the inherent superposition property of wireless channels. Personalized federated learning balances performance for users with diverse datasets, addressing real-life data heterogeneity. We propose the first personalized OTA-FL scheme through multi-task learning, assisted by personal reconfigurable intelligent surfaces (RIS) for each user. We take a cross-layer approach that optimizes communication and computation resources for global and personalized tasks in time-varying channels with imperfect channel state information, using multi-task learning for non-i.i.d data. Our PROAR-PFed algorithm adaptively designs power, local iterations, and RIS configurations. We present convergence analysis for non-convex objectives and demonstrate that PROAR-PFed outperforms state-of-the-art on the Fashion-MNIST dataset.
