Online Reinforcement Learning for Dynamic Multimedia Systems

TL;DR

This paper introduces online reinforcement learning algorithms for dynamic multimedia systems, enabling layers to learn optimal long-term performance strategies in real-time, with improved speed and autonomy over existing methods.

Contribution

The paper presents novel centralized and decentralized reinforcement learning algorithms tailored for multimedia systems, incorporating accelerated learning with partial system knowledge.

Findings

Decentralized learning matches centralized performance.

Proposed algorithms outperform existing application-independent methods.

Accelerated learning significantly speeds up convergence.

Abstract

In our previous work, we proposed a systematic cross-layer framework for dynamic multimedia systems, which allows each layer to make autonomous and foresighted decisions that maximize the system's long-term performance, while meeting the application's real-time delay constraints. The proposed solution solved the cross-layer optimization offline, under the assumption that the multimedia system's probabilistic dynamics were known a priori. In practice, however, these dynamics are unknown a priori and therefore must be learned online. In this paper, we address this problem by allowing the multimedia system layers to learn, through repeated interactions with each other, to autonomously optimize the system's long-term performance at run-time. We propose two reinforcement learning algorithms for optimizing the system under different design constraints: the first algorithm solves the cross-layer optimization in a centralized manner, and the second solves it in a decentralized manner. We analyze both algorithms in terms of their required computation, memory, and inter-layer communication overheads. After noting that the proposed reinforcement learning algorithms learn too slowly, we introduce a complementary accelerated learning algorithm that exploits partial knowledge about the system's dynamics in order to dramatically improve the system's performance. In our experiments, we demonstrate that decentralized learning can perform as well as centralized learning, while enabling the layers to act autonomously. Additionally, we show that existing application-independent reinforcement learning algorithms, and existing myopic learning algorithms deployed in multimedia systems, perform significantly worse than our proposed application-aware and foresighted learning methods.