IEEE 802.11e

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