Integrating admission control and packet scheduling for quality controlled streaming services in HSDPA networks

Abstract

High-Speed Downlink Packet Access (HSDPA) uses a shared forward link packet data channel that can achieve peak data rates up to 14.4 Mbps. The newly introduced features that are key to reaching such high rates are link adaptation, Hybrid ARQ (HARQ) and fast scheduling. The decision to admit new users is still taken by the Radio Network Controller (RNC); however, the scheduling role has been moved to the base station (Node-B) for fast adaptability. Although in high speed cellular networks, opportunistic scheduling can exploit multi-user diversity to maximize throughput, with the growing need for strict QoS guarantees for services such as streaming, gaming, and VoIP, a balance should be struck between maximizing throughput and providing user satisfaction. Service operators can enforce their own policies in providing user satisfaction. In this paper, we consider a QoS-aware policy driven scheduling algorithm and its interaction with the admission control mechanism at the RNC. We developed a dynamic HSDPA network simulator in OPNET with link adaptation, HARQ, fast scheduling and quality based admission control. Our simulations show that even with the presence of an admission controller at RNC, the well-known proportional fairness (PF) algorithm dismally fails to provide user satisfaction for streaming services, whereas our Strict Policy Scheduling (SPS) algorithm substantially increases user satisfaction as intended by the admission controller while providing a significant cell capacity gain.