Experiments in fair scheduling in 4G WiMAX and LTE

Abstract

LTE and WiMAX are broadband wireless technologies recognized as 4G. Both technologies support various multimedia applications such as voice over Internet protocol (VoIP), video conferencing and online gaming. In general, the network applications have diverse requirements to be satisfied including Quality of Service (QoS). Therefore, effective scheduling is critical for overall performance of 4G systems. Many traffic scheduling algorithms are available for wireless networks, e.g. Weighted Fair Queuing (WFQ), Earliest Deadline First (EDF) and Weighted Round Robin (WRR). In this work, an analysis of various scheduling algorithms in 4G networks based on QoS criteria is carried out. The WiMAX hybrid scheduling algorithm (EDF + WFQ + FIFO) provides strict priority to QoS traffic over BE subscriber requests. This may cause starvation when the concentration of nrtPS and BE is high. We have experimented with a modified hybrid algorithm (MOHSA) to provide a more equitable scheduling. Similarly, LTE has time domain QoS scheduling in GBR (1,2) and non-GBR (3,4 and 5) classes. We have implemented a variant of MOHSA in TD scheduler of LTE to ensure fairness. Results indicate a fair allocation of bandwidth and starvation avoidance for BE traffic.