Joint Client Scheduling and Resource Allocation under Channel Uncertainty in Federated Learning

TL;DR

This paper proposes a joint client scheduling and resource allocation strategy for federated learning over wireless networks, addressing channel uncertainty and limited resources to improve training performance.

Contribution

It introduces a stochastic optimization framework using Lyapunov optimization and Gaussian process regression for channel prediction, enhancing FL robustness under imperfect CSI.

Findings

Reduces training accuracy loss gap by up to 40.7%

Validates robustness under perfect and imperfect CSI

Improves resource utilization in federated learning

Abstract

The performance of federated learning (FL) over wireless networks depend on the reliability of the client-server connectivity and clients' local computation capabilities. In this article we investigate the problem of client scheduling and resource block (RB) allocation to enhance the performance of model training using FL, over a pre-defined training duration under imperfect channel state information (CSI) and limited local computing resources. First, we analytically derive the gap between the training losses of FL with clients scheduling and a centralized training method for a given training duration. Then, we formulate the gap of the training loss minimization over client scheduling and RB allocation as a stochastic optimization problem and solve it using Lyapunov optimization. A Gaussian process regression-based channel prediction method is leveraged to learn and track the wireless channel, in which, the clients' CSI predictions and computing power are incorporated into the scheduling decision. Using an extensive set of simulations, we validate the robustness of the proposed method under both perfect and imperfect CSI over an array of diverse data distributions. Results show that the proposed method reduces the gap of the training accuracy loss by up to 40.7% compared to state-of-theart client scheduling and RB allocation methods.