What are the key WLAN QoS standards and protocols that you need to know?

1 IEEE 802.11e

The IEEE 802.11e standard defines the enhancements to the medium access control (MAC) layer of the 802.11 WLAN protocol to support QoS features. It introduces two main mechanisms: enhanced distributed channel access (EDCA) and hybrid coordination function controlled channel access (HCCA). EDCA assigns different traffic categories (TCs) to different access categories (ACs), which have different contention window sizes and arbitration interframe spaces (AIFSs), to give higher priority to more delay-sensitive traffic. HCCA allows a hybrid coordinator (HC), usually the access point (AP), to poll stations and allocate transmission opportunities (TXOPs) based on their QoS needs.

2 Wi-Fi Multimedia (WMM)

Wi-Fi Multimedia (WMM) is a certification program developed by the Wi-Fi Alliance to certify products that implement the QoS features of the 802.11e standard. WMM defines four ACs: voice, video, best effort, and background, which map to the TCs of 802.11e. WMM also defines two optional extensions: WMM Power Save, which allows stations to save battery power by indicating their sleep and awake periods to the AP, and WMM Admission Control, which allows stations to request and reserve resources from the AP before sending QoS-sensitive traffic.

3 IEEE 802.11k

The IEEE 802.11k standard defines the radio resource management (RRM) enhancements to the 802.11 WLAN protocol to improve QoS and network efficiency. It allows stations and APs to exchange information about the radio environment, such as channel load, noise, interference, and signal strength, to facilitate better roaming decisions, load balancing, and interference mitigation. For example, an AP can use the 802.11k information to steer a station to a less congested channel or a closer AP.

4 IEEE 802.11r

The IEEE 802.11r standard defines the fast basic service set (BSS) transition (FT) enhancements to the 802.11 WLAN protocol to support QoS for voice and video applications that require seamless roaming across different APs. It reduces the authentication and reassociation time by allowing stations to establish security keys with multiple APs before moving, and by using a fast BSS transition protocol that bypasses the 802.1X authentication process. This way, stations can switch to a new AP without disrupting their ongoing sessions.

5 IEEE 802.11v

The IEEE 802.11v standard defines the wireless network management (WNM) enhancements to the 802.11 WLAN protocol to support QoS and network optimization. It allows stations and APs to exchange information about the network configuration, status, and preferences, to enable better network management and control. For example, an AP can use the 802.11v information to send a transition management request to a station, asking it to move to a different channel or a different AP, based on the network conditions and policies.

6 IEEE 802.11ax

The IEEE 802.11ax standard, also known as Wi-Fi 6, is the latest generation of the 802.11 WLAN protocol that introduces several QoS improvements and enhancements. It adopts the orthogonal frequency division multiple access (OFDMA) technology, which allows an AP to divide a channel into smaller subchannels and assign them to different stations, based on their QoS needs and traffic demand. It also introduces the multi-user multiple input multiple output (MU-MIMO) technology, which allows an AP to transmit or receive data from multiple stations simultaneously, using different spatial streams. These technologies increase the spectral efficiency, throughput, and capacity of the WLAN, and reduce the latency and contention.

7 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?