PLUS-DAC: a distributed admission control scheme for IEEE 802.11e WLANs

The IEEE 802.11e standard provides many mechanisms for Quality of Service (QoS) support at the MAC layer level. However, the service differentiation provided in IEEE 802.11e is not enough to meet the QoS requirements of time bounded multimedia traffic. These can be better satisfied, if we employ Admission Control and Bandwidth Reservation mechanisms. In this paper, we discuss a measurement based distributed admission control mechanism, for the IEEE 802.11e Wireless Local Area Network (WLAN) functioning in infrastructure mode. We call the scheme PLUS-DAC (Priority, Load and Utilization based Scheme for Distributed Admission Control). PLUS-DAC measures the load and utilization in the BSS and adapts the Transmission Opportunity (TXOP) allocation dynamically. Our results show that, PLUS-DAC can achieve quasi-optimal utilization and continue to satisfy QoS guarantees given to multimedia flows.© IEE