Macro-scheduling of base stations for video-on-demand flows in WiMAX networks

We consider lifetime quality-of-experience (QoE) management for video-on-demand (VoD) users in WiMAX networks. For efficient resource utilization while enhancing user experience, we propose run-time load balancing through joint scheduling among multiple base stations (BSs), referred to as macro scheduling. Macro scheduling employs a utility-maximization approach. To achieve long-term proportional fairness (PF) and manage lifetime QoE, user and flow utilities are modeled as functions of their past service rates, in addition to current channel conditions and bandwidth needs. We show that scheduling flows across multiple BSs jointly to achieve PF is NP-hard in the strong sense. Since approximation algorithms proposed in prior work are computationally expensive for online use, we design efficient heuristics that perform as well as the approximation algorithms. A simulation-based evaluation shows that our overall macro scheduling scheme can improve the number of satisfied users by up to 35% in comparison to other approaches, while only minimally sacrificing on throughput.