Nebula: Reliable Low-latency Video Transmission for Mobile Cloud Gaming

TL;DR

Nebula is a novel cloud gaming framework that adaptively manages video streaming to minimize latency and losses, significantly improving user experience over variable mobile networks.

Contribution

It introduces an end-to-end distortion model that dynamically adjusts video rate and redundancy based on network conditions, enhancing real-time mobile cloud gaming performance.

Findings

Nebula achieves low latency (<140 ms) and high visual quality (>31 dB) in variable environments.

It outperforms existing techniques in balancing latency and quality.

User studies show improved perceived quality and playability.

Abstract

Mobile cloud gaming enables high-end games on constrained devices by streaming the game content from powerful servers through mobile networks. Mobile networks suffer from highly variable bandwidth, latency, and losses that affect the gaming experience. This paper introduces Nebula, an end-to-end cloud gaming framework to minimize the impact of network conditions on the user experience. Nebula relies on an end-to-end distortion model adapting the video source rate and the amount of frame-level redundancy based on the measured network conditions. As a result, it minimizes the motion-to-photon (MTP) latency while protecting the frames from losses. We fully implement Nebula and evaluate its performance against the state of the art techniques and latest research in real-time mobile cloud gaming transmission on a physical testbed over emulated and real wireless networks. Nebula consistently balances MTP latency (<140 ms) and visual quality (>31 dB) even in highly variable environments. A user experiment confirms that Nebula maximizes the user experience with high perceived video quality, playability, and low user load.