Delay optimized worst case fair WFQ (WF2Q) packet scheduling

The worst-case fairness index (WFI) has proved to be an important metric in the provision of fairness and bounded delay in both wired and wireless networks. Worst case fair WFQ (WF²Q) is better than weighted fair queuing (WFQ) in that it can provide bounded WFI. However, simulations show that in some circumstances WF²Q has higher WFI and queuing delay than WFQ. This paper firstly analyzes the reasons why WF²Q sometimes experiences higher WFI, and based on this, an adaptive packet queuing algorithm termed delay optimized WF²Q (DO-WF²Q), is proposed. This algorithm aims to improve the delay index (DI) while maintaining the WFI bound provided by WF²Q. Verifications and simulations show that DO-WF²Q can reduce DI while not destroying the WFI bound, and at the same time maintain low complexity.