A Deficit Round Robin with Fragmentation scheduler for IEEE 802.16e Mobile WiMAX

Deficit round robin (DRR) is a fair packet-based scheduling discipline commonly used in wired networks where link capacities do not change with time. In wireless networks especially wireless broadband networks such as IEEE 802.16e Mobile WiMAX, the link capacity can change over time and also depends on the user location. Moreover, Mobile WiMAX allows packet fragmentation which violates the packet-based service concept of DRR. Therefore, the traditional DRR can not directly be used in such networks. Therefore, we introduce Deficit round robin with fragmentation (DRRF) to allocate resources in a fair manner, while allowing for varying link capacity. Similar to DRR and general processor sharing (GPS), the DRRF achieves perfect fairness. DRRF results in a higher throughput than DRR while causing less overhead than GPS. In addition, we extend DRRF to support users with minimum reserved traffic rate, maximum sustained traffic rate and traffic priority.