A Study Of Packet Scheduling Lgorithm Based On Qos In HSDPA

Data services are anticipated to have an enormous rate of growth over the next years and will likely become the dominating source of traffic load in 3G mobile cellular networks. The provision of these data services in 3G systems requires spectral efficiency solutions to increase the capacity of the radio access netork as well as support for high data rates. In this context, the 3GPP introduces a new feature in the Rel5 specifications denominated High Speed Downlink Packet Access (HSDPA). The target of the HSDPA concept is to increase the peak data rates, improve the quality of service, and enhance the spectral efficincy for downlink packet traffic.The HSDPA concept utilizes a series of adaptation technologies to improve both user and system performance. The concept includes a reduction of the Transmission Time Interval (TTI) to 2ms, an Adaptive Modulation and Coding (AMC) scheme, and a fast physical layer Hybrid ARQ mechanism. Moreover, the Packet Scheduler functionality is located in the Node B, which enables to track instantaneous variations of the user's channel quality. The services that could potentially be conveyed by HSDPA are streaming, interactive, and background services.QoS demands of the different traffic classes, the protocols employed in their communication, and the statistical properties of the traffic are investigated. In the case of NRT services, the main interest is in HTTP and its characteristics because Web traffic is expected to be one of the key services in 3G networks.The investigation has specially concentrated on assessing different Packet Scheduling methods with different degrees of fairness for non delay-sensitive services because it determines the QoS perceived by the users. The results have shown that under minimum throughput guarantees the Proportional Fair algorithm provides the highest cell capacity of all tested algorithms. With this...