A cloud-assisted energy-efficient video streaming system for smartphones

Due to the increasing deployment of 3G/4G technologies and the growing computing power of modern smart-phones, video streaming is one of the most popular applications on these devices. In this paper, we propose an energy-efficient multimedia streaming system for smartphones. This system simultaneously utilizes two communication channels: cellular links carrying streaming content from the media Cloud to smartphones and WiFi links enabling cooperation among smartphones. There are three key contributions. First, the system copes with the variable loss rate and bandwidth fluctuation, common problems in wireless communication, by taking advantage of a novel two-level coding scheme. Second, the system reduces energy consumption due to network coding operations, by utilizing the copious computing resources in the Cloud. Consequently, XOR-only network coding is sufficient for sharing among smartphones. Third, we propose a light-weight distributed scheduling algorithm to manage collaboration and content sharing among the neighbouring nodes. The proposed local dissemination scheme, along with the proposed two-level coding scheme, outperforms state-of-the-art streaming systems in cellular networks. Our experimental results show that our proposed system saves up to 73% of battery usage on each phone compared to the current streaming mechanism over a 3G network. In addition, the system is capable to support higher quality streaming and decrease the streaming delay.