Small-Scale-Fading-Aware Resource Allocation in Wireless Federated Learning

TL;DR

This paper introduces a small-scale-fading-aware resource allocation method for wireless federated learning using multi-agent reinforcement learning, improving training efficiency by accounting for rapid channel fluctuations.

Contribution

It develops a decentralized MARL framework with QMIX for resource allocation that considers small-scale fading, a novel approach in FL over wireless networks.

Findings

Significant performance gains over baseline methods.

Effective handling of statistical heterogeneity.

Validation of small-scale fading's impact on FL performance.

Abstract

Judicious resource allocation can effectively enhance federated learning (FL) training performance in wireless networks by addressing both system and statistical heterogeneity. However, existing strategies typically rely on block fading assumptions, which overlooks rapid channel fluctuations within each round of FL gradient uploading, leading to a degradation in FL training performance. Therefore, this paper proposes a small-scale-fading-aware resource allocation strategy using a multi-agent reinforcement learning (MARL) framework. Specifically, we establish a one-step convergence bound of the FL algorithm and formulate the resource allocation problem as a decentralized partially observable Markov decision process (Dec-POMDP), which is subsequently solved using the QMIX algorithm. In our framework, each client serves as an agent that dynamically determines spectrum and power allocations within each coherence time slot, based on local observations and a reward derived from the convergence analysis. The MARL setting reduces the dimensionality of the action space and facilitates decentralized decision-making, enhancing the scalability and practicality of the solution. Experimental results demonstrate that our QMIX-based resource allocation strategy significantly outperforms baseline methods across various degrees of statistical heterogeneity. Additionally, ablation studies validate the critical importance of incorporating small-scale fading dynamics, highlighting its role in optimizing FL performance.