Performance Analysis of Multimedia Traffic over HSDPA

Contents 2.1 Introduction 48 2.2 Scenario and Model Description 502.2.1 Multicell Propagation Model 51 2.2.2 System and User Characteristics 532.3 Scheduling 54 2.3.1 Round-Robin Scheduler 55 2.3.2 Max C/I Scheduler 55 2.3.3 Proportional Fair Scheduler 56 2.3.4 Time-To-Live Scheduler 572.4 Analysis of the Default Scenario 57 2.4.1 Validation of Cell Selection 57 2.4.2 Mixed Traffic Scenario 592.5 Mobility: Optimization of Handover Parameters 62 2.5.1 Handover Threshold 622.6 Performance of Different Scheduler Algorithms 682.6.1 Specific Scheduler Properties 68 2.6.2 Priority Scheduling 75 2.6.3 Comparison of Scheduling Algorithms 78 2.6.4 Consumption of System Resources 802.7 Conclusion 82 2.8 Open Issues 84 Acknowledgments 85 References 852.1 Introduction The rapid advances in wireless technologies have brought about a worldwide demand for high quality multimedia applications and services. These will particularly appear in the Internet, as well as in wireless scenarios [1,2]. Real-time services over high speed downlink packet access (HSDPA) is an issue under discussion in 3rd Generation Partnership Project (3GPP) [3,4]. A key improvement of Universal Mobile Telecommunications System (UMTS) has been realized with HSDPA, which has been defined for release 5 of the UMTS standard within 3GPP. HSDPA aims at increasing the systems capacity and the users’ peak throughput from 2 to over 10 Mbps. Its transmission time feedback loop is smaller than that of regular UMTS and the scheduling functionality is no longer in the radio network controller (RNC) but in the Node-B (base station). As a result, the fluctuations in the radio channel fading characteristics can be better tracked. Scheduling of data flows is a key mechanism to provide quality of service (QoS) and optimize resource efficiency. Whereas the former objective is clearly the most important to the user, the latter is essential for the operator.