

These are “Block Acknowledgement”, “Direct Link Setup”, “Automatic Power Save Delivery” among others. Please recall that DCF is contention based while PCF is contention free access methods in 802.11Ī few additional mechanisms have been added to improve channel utilization and efficiency. Parameterized QoS, on the other hand, is a strict requirement expressed quantitatively in terms of the QoS parameters.Ī new access mechanism (called as HCF – Hybrid Coordination Function) has been defined with EDCA for contention based and HCCA for contention free access methods. Prioritized QoS is a weak requirement that enforces relative priority between traffic classes.

In IEEE 802.11e, two types of QoS are identified – prioritized QoS and parameterized QoS.
