Mitigating Modality Quantity and Quality Imbalance in Multimodal Online Federated Learning

TL;DR

This paper addresses the challenges of modality quantity and quality imbalance in multimodal online federated learning for IoT, proposing a novel algorithm that improves learning performance under imbalance conditions.

Contribution

It systematically analyzes the impact of modality imbalance in MMO-FL and introduces the QQR algorithm to mitigate these issues effectively.

Findings

Theoretical analysis quantifies the impact of QQI on performance.

The QQR algorithm outperforms benchmarks under imbalance conditions.

Experimental results on real-world datasets demonstrate improved learning outcomes.

Abstract

The Internet of Things (IoT) ecosystem produces massive volumes of multimodal data from diverse sources, including sensors, cameras, and microphones. With advances in edge intelligence, IoT devices have evolved from simple data acquisition units into computationally capable nodes, enabling localized processing of heterogeneous multimodal data. This evolution necessitates distributed learning paradigms that can efficiently handle such data. Furthermore, the continuous nature of data generation and the limited storage capacity of edge devices demand an online learning framework. Multimodal Online Federated Learning (MMO-FL) has emerged as a promising approach to meet these requirements. However, MMO-FL faces new challenges due to the inherent instability of IoT devices, which often results in modality quantity and quality imbalance (QQI) during data collection. In this work, we systematically investigate the impact of QQI within the MMO-FL framework and present a comprehensive theoretical analysis quantifying how both types of imbalance degrade learning performance. To address these challenges, we propose the Modality Quantity and Quality Rebalanced (QQR) algorithm, a prototype learning based method designed to operate in parallel with the training process. Extensive experiments on two real-world multimodal datasets show that the proposed QQR algorithm consistently outperforms benchmarks under modality imbalance conditions with promising learning performance.