Joint Coding and Scheduling Optimization for Distributed Learning Over Wireless Edge Networks

• Published in: IEEE journal on selected areas in communications Vol. 40; no. 2; pp. 484 - 498
• Main Authors: Van Huynh, Nguyen, Hoang, Dinh Thai, Nguyen, Diep N., Dutkiewicz, Eryk
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.02.2022; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Academic degrees; Algorithms; Coded computing; Codes; Coding; Cognitive tasks; Computer aided instruction; Computer architecture; deep dueling neural network; Deep learning; deep reinforcement learning; Distance learning; distributed learning; Edge computing; Encoding; Machine learning; Markov processes; Neural networks; Nodes; Optimization; Redundancy; reinforcement learning; Scheduling; Servers; Service introduction; Task analysis; Uncertainty; Wireless communication; wireless edge networks; Wireless networks
• ISSN: 0733-8716; 1558-0008
• DOI: 10.1109/JSAC.2021.3118432

Unlike theoretical analysis of distributed learning (DL) in the literature, DL over wireless edge networks faces the inherent dynamics/uncertainty of wireless connections and edge nodes, making DL less efficient or even inapplicable under the highly dynamic wireless edge networks. This article addresses these problems by leveraging recent advances in coded computing and the deep dueling neural network architecture. By introducing coded structures/redundancy, a distributed learning task can be completed without waiting for straggling nodes. Unlike conventional coded computing that only optimizes the code structure, coded distributed learning over the wireless edge also requires to optimize the selection/scheduling of wireless edge nodes with heterogeneous connections, computing capability, and straggling effects. However, even neglecting the aforementioned dynamics/uncertainty, the resulting joint optimization of coding and scheduling to minimize the distributed learning time turns out to be NP-hard. To tackle this and to account for the dynamics and uncertainty of wireless connections and edge nodes, we reformulate the problem as a Markov Decision Process and design a novel deep reinforcement learning algorithm that employs the deep dueling neural network architecture to find the jointly optimal coding scheme and the best set of edge nodes for different learning tasks without explicit information about the wireless environment and edge nodes' straggling parameters. Simulations show that the proposed framework reduces the average learning delay in wireless edge computing up to 66% compared with other DL approaches. The jointly optimal framework in this article is also applicable to any distributed learning scheme with heterogeneous and uncertain computing nodes.