Fair downlink packet scheduling approach to support QoS in HSDPA environment

Abstract

Traditionally, only best-effort traffic is supported by packet switching networks, but newer applications need communication services that allow end client to transport data with performance guarantees given in terms of data transfer reliability, available bandwidth and delay bounds. The choice of the packet-scheduling algorithm to be used at switching nodes is very crucial to provide the Quality of Service, QoS.

This work aims at designing a downlink packet scheduling approach to QoS provisioning in High Speed Downlink Packet Access, HSDPA, based UMTS networks. In UMTS a single logical channel is shared among multiple contending users. Besides better link utilization, scheduling disciplines seek to achieve fair allocation of this shared resource. However, these two criterions can potentially be in conflict. In this work a scheduling discipline, \Wireless Fair - High Speed Scheduling", is proposed, which addresses the above-mentioned conflict. The idea is to allocate the channel fairly among users, even during short time scales, according to their data rate requirements.

The proposed algorithm is compared with Adaptive Proportional Fair Algorithm, which provides fair distribution of channel bandwidth, proportional to the data rate requirements of users. Several experiments were conducted using simulation for comparing the performance of the algorithms in different scenarios. The results ensure that the proposed scheduling algorithm provides better link utilization, and long-term and short-term fairness among users even in heavy load conditions.