Delay-Based Admission Control to Sustain QoS in a Managed IEEE 802.11 Wireless LANs

In this chapter, we present a delay-sensitive MAC adaptation scheme combined with an admission control mechanism. The proposed solution is based on thorough analysis of the trade-off existing between high network utilization and achieving bounded QoS metrics in operated 802.11-based networks. First, we derive an accurate delay estimation model to adjust the contention window size in real-time basis by considering key net-work factors, MAC queue dynamics, and application-level QoS requirements. Second, we use the abovementioned delay-based CW size adaptation scheme to derive a fully distributed admission control model that provides protection for existing flows in terms of QoS guarantees.