QoE-Aware Joint Scheduling of Buffered Video on Demand and Best Effort Flows

摘要

Since video services are expected to constitute a major portion of the mobile downlink traffic, it is important to consider end users' perceptual quality of experience (QoE) for video traffic in the system design and performance evaluation of next generation mobile networks. We present a novel QoE-aware scheduling scheme for buffered video on demand (VoD). Therein, rebuffering is the critical attribute undermining users' QoE. Our scheduling scheme is based on 'vacuum pressure scheduling'. We use playback buffer vacancy and apply the 'backpressure' scheduling theory to schedule the VoD flows. The proposed scheme is further adjusted to enable joint scheduling of a mixture of VoD and best effort (BE) flows within the same band. A simple control knob is provided to operators to softly adjust the region in which BE flows contend on resources. Results demonstrate substantial user capacity gains compared to prior work without compromising the QoS of BE flows. Sensitivity analysis to feedback periodicity shows remarkable robustness and overhead savings compared to the baseline. Results even hold when requested videos are of heterogeneous qualities, i.e., encoding rates.