ABSTRACT
Contents 5.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 173 5.2 Packet Scheduling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 175
5.2.1 Quality-of-Service-Aware Scheduling . . . . . . . . . . . . . . . . . . . . . . . 177 5.3 Packet Scheduling Algorithms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 179
5.3.1 Best-Effort Schedulers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180 5.3.2 QoS Schedulers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 185
5.3.2.1 Weighted Delay-Based Schedulers . . . . . . . . . . . . . . . . . 187 5.3.2.2 Utility-Based Schedulers . . . . . . . . . . . . . . . . . . . . . . . . . . . 191 5.3.2.3 Required Activity Detection Scheduler . . . . . . . . . . . . 195 5.3.2.4 Comparison among the Different QoS-Aware
Schedulers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 196 5.4 Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 200 5.5 Conclusion. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 202
5.1 Introduction This chapter presents the packet scheduling principles and different scheduling algorithms for High-Speed Downlink Packet Access (HSDPA). HSDPA is an enhancement of UMTS (Universal Mobile Telecommunications
System) networks that supports data rates of several megabits per second (Mbps), making it suitable for data applications ranging from file transfer to multimedia streaming. Despite the fairly high data rates that HSDPA offers, the shared downlink radio channel used in HSDPA is a challenging environment for delay-and loss-sensitive applications like video streaming. Thus, resource management algorithms are needed to ensure good quality-of-service.
