Editing IEEE 802.16 (section)

=== MAC ===
The 802.16 MAC describes a number of ''Convergence Sublayers'' which describe how wireline technologies such as [[Ethernet]], [[Asynchronous Transfer Mode]] (ATM) and [[Internet Protocol]] (IP) are encapsulated on the [[air interface]], and how data is classified, etc. It also describes how secure communications are delivered, by using secure key exchange during authentication, and encryption using [[Advanced Encryption Standard]] (AES) or [[Data Encryption Standard]] (DES) during data transfer. Further features of the MAC layer include power saving mechanisms (using ''sleep mode'' and ''idle mode'') and handover mechanisms.

A key feature of 802.16 is that it is a [[Connection-oriented communication|connection-oriented]] technology. The subscriber station (SS) cannot transmit data until it has been allocated a channel by the [[base station]] (BS). This allows 802.16e to provide strong support for quality of service (QoS).

==== QoS ====
[[Quality of service]] (QoS) in 802.16e is supported by allocating each connection between the SS and the BS (called a ''service flow'' in 802.16 terminology) to a specific ''QoS class''. In 802.16e, there are 5 QoS classes:

{| class="wikitable"
|+ 802.16e-2005 QoS classes
!Service
!Abbrev
!Definition
!Typical Applications
|-
|Unsolicited Grant Service|| UGS || Real-time data streams comprising fixed-size data packets issued at periodic intervals ||T1/E1 transport
|-
|Extended Real-time Polling Service||ertPS||Real-time service flows that generate variable-sized data packets on a periodic basis	||VoIP
|-
|Real-time Polling Service||rtPS||Real-time data streams comprising variable-sized data packets that are issued at periodic intervals||MPEG Video
|-
||Non-real-time Polling Service||nrtPS||Delay-tolerant data streams comprising variable-sized data packets for which a minimum data rate is required||FTP with guaranteed minimum throughput{{Citation needed|date=October 2008}}
|-
|Best Effort||BE||Data streams for which no minimum service level is required and therefore may be handled on a space-available basis||HTTP
|}

The BS and the SS use a service flow with an appropriate QoS class (plus other parameters, such as bandwidth and delay) to ensure that application data receives QoS treatment appropriate to the application.