The Institute of Electrical and Electronic Engineers (IEEE) is the organization responsible for the standards that define modern wireless enterprise networks, for example, WLANs. Industry interests are coordinated through the Wi-Fi Alliance. They select the subset of features that become the minimum set of features for certified hardware, software, and devices. They also control the use of trademarks.
The IEEE uses a unique numbering sequence for every standard. The 802 standard is for networking but is further broken down into 22 subparts. 802.11 is the sub-part for wireless networking. Over the past 20 years, the 802.11 standard has been updated many times beginning with revision 802.11a and continuing through 802.11ax. Some of the updates addressed specific technical shortcomings (for example, QoS) of the original standard, while others substantially changed fundamentals of the wireless protocol (for example, QAM modulation). In retrospect, the fundamental changes were generational changes.
It is simply the IEEE and Wi-Fi Alliance acknowledging the benefit of explicitly identifying the major generational changes within the 802.11 specification family. See the table below.
The technical changes equip Wi-Fi 6 to handle very high user device density per access point (AP) and the demands of 4K and 8K streaming video or multiuser virtual/augmented reality (VR/AR). There are four significant changes.
The first three changes are only applicable to 802.11ax APs communicating with 802.11ax user devices. The first change is an increase from 4 x 4 MIMO to 8 x 8 MIMO that can direct the eight data streams to a single user (achieving higher peak speed) or simultaneously assign one data stream to each of eight users, for example, multi-user MIMO (achieving lower average latency). The second is an increase in the RF signal modulation from 256 quadrature amplitude modulation (QAM) to 1024 QAM for 25 percent higher peak speeds for users in close proximity to the AP. The third change adds scheduling to the OFDM (becoming OFDMA) to provide deterministic use of the time-frequency resources when all devices are participating in MU-MIMO. The fourth change uses the increased number of antennas required to support 8 x 8 MIMO to provide more directional beamforming and allows more effective noise suppression (maximum ratio combining [MRC]), providing benefit to all users, including legacy users.
802.11ax still uses the original Carrier Sense Multiple Access (CSMA) technique using Clear Channel Assessment (CCA). CCA/CSMA is contention based, not deterministic, and is the root cause of most Wi-Fi latency and jitter issues. When all devices are 802.11ax, the CCA thresholds can be adjusted for higher average AP capacity – with the trade-off of potentially lower peak speeds.
Enterprise WLANs should be upgraded on a six- or seven-year cycle to avoid network equipment end of life (EOL) or end of support (EOS). If you have a validated use case involving high user density and streaming video, then Wi-Fi 6 is the obvious choice. If your usage scenarios are more typical enterprise applications, then upgrade with current mainstream equipment – Wi-Fi 5 or Wi-Fi 6.