Cloud Fog: Towards High Quality of Experience in Cloud Gaming

With the increasing popularity of Massively Multiplayer Online Game (MMOG) and fast growth of mobile gaming, cloud gaming exhibits great promises over the conventional MMOG gaming model as it frees players from the requirement of hardware and game installation on their local computers. However, as the graphics rendering is offloaded to the cloud, the data transmission between the end-users and the cloud significantly increases the response latency and limits the user coverage, thus preventing cloud gaming to achieve high user Quality of Experience (QoE). To solve this problem, previous research suggested deploying more data centers, but it comes at a prohibitive cost. We propose a lightweight system called Cloud Fog, which incorporates "fog" consisting of super nodes that are responsible for rendering game videos and streaming them to their nearby players. Fog enables the cloud to be only responsible for the intensive game state computation and sending update information to super nodes, which significantly reduce the traffic hence the latency and bandwidth consumption. To further enhance QoE, we propose the receiver-driven encoding rate adaptation strategy to increase the playback continuity and the deadline-driven sender buffer scheduling strategy to ensure that the segments arrive at the players within their response latency. Experimental results from Peer Sim and Planet Lab show the effectiveness and efficiency of Cloud Fog and our individual strategies in increasing user coverage, reducing response latency and bandwidth consumption.