QoE-aware Assignment and Scheduling of Video Streams in Heterogeneous Cellular Networks

Managing Quality of Experience (QoE) for users streaming videos over cellular networks (e.g., 4G LTE networks) is an important problem. In this paper, we consider the problem of streaming multiple variable bit rate (VBR) video streams to users over heterogeneous cellular networks (HetNets) comprising of a cellular infrastructure and storageenabled femtocells that are capable of caching content. We assume that each user can be connected to multiple femtocells simultaneously with the wireless channel quality between users and femtocells varying spatially as well as temporally. We address the joint assignment and scheduling problem, where the assignment problem is to match users to femtocells from where the video can be downloaded and the scheduling problem is to fairly allocate time slots to the different users that are assigned to the same femtocell. Our objective is to maximize the total bit rate received by the users considering all femtocells, subject to the QoE-based video streaming constraint that the number of stalls received by the users is bounded. We formulate the joint assignment and scheduling problem as an optimization problem and develop QoE-aware greedy algorithms that tackle the assignment and scheduling problems separately. We conduct trace-based experiments using real-world 4G LTE wireless connectivity and VBR video traces and demonstrate that our solution outperforms baselines in terms of average number of stalls per user (48% less on average) and results in a fair distribution of stalls across all users.