Trusted Collaboration for MEC-Enabled VR Video Streaming: A Multi-Agent Reinforcement Learning Approach

Collaboration among mobile edge computing (MEC) has been envisioned as a promising paradigm to meet the requirements of wireless virtual reality (VR) applications. However, trust risks create tremendous challenges in MEC collaboration due to the distributed, complex, and unreliable nature of resource providers. In this paper, we present a trusted collaboration framework for VR video streaming to manage the video buffer in VR devices (VDs) under a more realistic distributed environment. In the framework, the rendering tasks can be processed collaboratively among edge servers (ESs) by exploring their behaviors (e.g., selfish behavior, malicious behavior, and cooperative behavior). Considering the collaborator may not be fully trustworthy, we present a novel trust evaluation method by combining direct and indirect values, aiming to ensure reliable collaborator selection. Then, we formulate an optimization problem to maintain an effective buffer state in VR devices (VDs) through jointly optimizing collaborator selection, spectrum allocation, and rendering resource allocation. Due to the fluctuating wireless fading channel and the dynamic video rate, the optimization problem is intractable by adopting traditional methods. Then, we adopt the multi-agent deep deterministic policy gradient (MADDPG) to tackle this dynamic and distributed problem. Simulation results indicate that the proposed approach can achieve a good performance.