What is IEEE 802.11e?
IEEE 802.11e-2005 or 802.11e is an approved amendment to
the IEEE 802.11 standard that defines a set of Quality of
Service (QoS) enhancements for wireless local area network
(LAN) applications through modifications to the media access
control (MAC) layer. The standard is considers of critical importance
for delay-sensitive applications, such as voice over wireless
LAN and streaming multimedia. The amendment has been incorporate into
the published IEEE 802.11-2007 standard.
IEEE 802.11e Specifications
- Original
802.11 Media Access Control (MAC)
- Distributed
Coordination Function (DCF)
- Point
Coordination Function (PCF)
Media Access Control (MAC) Protocol Operations
A diagram of the 7-layer OSI model with the modifications made by the 802.11
standard and the 802.11e amendment
The 802.11e enhances the DCF and the PCF, through a new coordination
function: the hybrid coordination function (HCF). Within the HCF, there are two
methods of channel accessed, similar to those defined in the legacy 802.11 MAC:
HCF Controlled Channel Access (HCCA) and Enhanced Distributed Channel Access
(EDCA). Both EDCA and HCCA define Traffic Categories (TC). For
example, emails could be assigned to a low priority class, and Voice
over Wireless LAN (VoWLAN) could be assigned to a high priority class.
- Enhanced
Distributed Channel Access (EDCA)
- Hybrid
Coordination Function (HCF) Controller Channel Access (HCCA)
Other IEEE 802.11e Specifications
- Automatic
Power Save Delivery
- Block
Acknowledgements
- NoAck
- Direct
Link Setup
Learn about IEEE 802.11X
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