The Uniformly-Fair Deficit Round-Robin (UF-DRR) Scheduler for Improved QoS Guarantees in IEEE 802.16 WiMAX Networks

We propose a fair and efficient scheduling algorithm for broadband wireless networks, which we refer to as Uniformly-Fair Deficit Round Robin (UF-DRR). Our algorithm, which is designedfor the IEEE 802.16 MAC, gives bandwidth and delay guarantees to QoS sensitive applications while maintaining fairness amongflows and achieving high system utilization. Our scheme is a refined version of the Wireless Deficit Round Robin (WDRR) technique proposed by Fattah and Leung. We modify the redistribution strategy of WDRR to achieve better performance in terms ofdelay, throughput, andfairness, and analyze the performance of our scheme via exhaustive packet-level simulations, under realistic wireless scenarios. This contrasts with most of the previous work, where the analysis and simulations were confined to only an error-free system. The effects of system parameters like channel quality are also studied in our work. We demonstrate that under all channelfading characteristics and for the range of applicable loads, UF-DRR is capable ofproviding bounded delay, fairness, and high throughput. We show that UF-DRR outperforms WDRR and DRR in the wireless environment, giving, on average, throughput that is 30% higher and fairness that is 20-30% better, even when the wireless channel is good only 50% of the time.