What is Wi-Fi 6 (802.11ax), and why do we need it?

Wi-Fi has become an indispensable technology in enterprise networks, supporting enough bandwidth and individual channels to make all-wireless LANs feasible, thanks in large part to 802.11ax, the standard more commonly called Wi-Fi 6.

What is 802.11ax (Wi-Fi 6)?

Wi-Fi 6 was officially certified in 2020 and has quickly become the de facto standard for wireless LAN technology (WLAN), superseding Wi-Fi 5 (802.11ac). Wi-Fi 6 delivers improved performance, extended coverage and longer battery life compared to Wi-Fi 5.

Wi-Fi 6 was originally designed to address bandwidth problems associated with dense, high-traffic environments such as airports, stadiums, trains and offices. However, the explosion of IoT devices that need to connect wirelessly to edge devices, and the ever-increasing bandwidth needs of new data-thirsty applications has rendered Wi-Fi 6 not exactly obsolete on arrival, but certainly not sufficient for some use cases.

As a result, Wi-Fi 6 is already being supplemented by an even newer standard called Wi-Fi 6E (the E stands for extended), which takes Wi-Fi 6 technology and runs it on newly available unlicensed spectrum in the 6Ghz range to deliver even better performance.

How does Wi-Fi 6 work?

Wi-Fi 6 takes a variety of well-understood wireless techniques and combines them in a way that achieves a significant advance over previous standards yet maintains backward compatibility with previous generations.

Wi-Fi 6 delivers a nearly 40% increase in pure throughput thanks to higher order QAM modulation, which allows for more data to be transmitted per packet. It also achieves more efficient spectrum utilization. For example, it creates broader channels and splits those channels into narrower sub-channels. This increases the total number of available channels, making it easier for endpoints to find a clear path to the access point.

When it comes to downloads from the access point to the end user, early Wi-Fi standards only permitted one transmission at a time per access point. The Wave 2 version of Wi-Fi 5 began using Multi-User, Multiple-Input, Multiple Output (MU-MIMO),

which allowed access points to send up to four streams simultaneously. Wi-Fi 6 allows for eight simultaneous streams and makes use of explicit beamforming technology to aim those streams more accurately at the receiver’s antenna.

Even more importantly, Wi-Fi 6 piggybacks on MU-MIMO with an LTE cellular base station technology called Orthogonal Frequency Division Multiple Access (OFDMA). This allows each MU-MIMO stream to be split in four additional streams, boosting the effective bandwidth per user by four times.

How is Wi-Fi 6 different from Wi-Fi 5?

Wi-Fi 5 operates in the 5Ghz range only, while Wi-Fi 6 operates in both the 2.4Ghz and 5Ghz ranges, thus creating more available channels. For example, Wi-Fi 6 chipsets support a total of 12 channels, eight in the 5Ghz and four in the 2.4Ghz range.

With Wi-Fi 5, MU-MIMO is limited to downlink transmissions only. Wi-Fi 6 supports MU-MIMO connections in both directions. With downlink MU-MIMO, an access point may transmit concurrently to multiple receivers, and with uplink MU-MIMO an endpoint may simultaneously transmit to an access point.  

Wi-Fi 6 supports up to eight MU-MIMO transmissions at a time, up from four with Wi-Fi 5. OFDMA is new with Wi-Fi 6, as are several other technologies, like trigger-based random access, dynamic fragmentation and spatial frequency re-use, all aimed at improving efficiency.

Finally, Wi-Fi 6 introduces a technology called “target wake time” to improve wake and sleep efficiency on smartphones and other mobile devices. This technology is expected to make a significant improvement in battery life.

What applications benefit from Wi-Fi 6?

Wi-Fi 6 helps organizations address bandwidth and range issues associated with existing technologies like IoT or IT/OT integration. Historically, organizations have turned to niche, high-speed, low-latency, short-range wireless technologies like Zigbee for IoT device connectivity, but the powerful capabilities of Wi-Fi 6 enable organizations to reduce complexity by standardizing on Wi-Fi across all wireless-related applications.

It also enables organizations to support emerging technologies such as 4K/8K video and augmented/virtual reality (AR/VR). There are a variety of use cases in this area including telemedicine, all-wireless offices, remote field support, virtual training and collaboration.

What is Wi-Fi 6E?

The “6” in Wi-Fi 6 refers to the sixth generation of the technology. Wi-Fi 6E uses the same underlying technology as Wi-Fi 6, but runs on the 6-GHz unlicensed spectrum that has been made available for Wi-Fi. 

The 2.4-GHz band comprises 11 channels that are each 20 megahertz (MHz) wide. The 5-GHz band has 45 channels that can 40-MHz or 80-MHz wide. The 6-GHz band supports 60 channels that can be up to 160 MHz wide, delivering a quantum leap in terms of capacity, reliability and security.

The big gotcha is that Wi-Fi 6E requires Wi-Fi 6E compatible hardware for both access points and end-user devices. Wi-Fi 6 routers are backward compatible, which means they can connect to Wi-Fi 5- or Wi-Fi 6-compatible devices, but only via Wi-Fi 5 or Wi-Fi 6, not via Wi-Fi 6E. Only routers and devices with Wi-Fi 6E support can operate on the 6-GHz band. So, organizations need to conduct an analysis to determine whether the benefits of upgrading to Wi-Fi 6E justify the expense of the proverbial forklift upgrade.

What are the benefits of Wi-Fi 6E

Wi-Fi 6E is able to build on the core Wi-Fi 6 technology in a number of ways:

• Capacity: The additional spectrum delivers more nonoverlapping channels so Wi-Fi 6E can support dense IT and IoT environments with no degradation of performance.
• Reliability:Because this is a truly greenfield scenario, network architects can be confident that there are no other device types (microwave ovens) using the spectrum, which means there is no interference or competition for the bandwidth from other wireless sources.
• Security:WPA3, which provides new authentication and encryption algorithms for networks, is a mandatory requirement for the Wi-Fi 6E network.

Wi-Fi 6 vs 5G

Wi-Fi 6 and 5G are different technologies: wireless LAN vs. cellular. But they share some similarities: They represent the latest generation of technology in their respective spheres of influence, they both offer tremendous promise, and they can coexist.

While Wi-Fi certainly works outdoors (as long as there’s a strong access point nearby) and cellular works indoors (although you might not get many bars), generally speaking, Wi-Fi is built for indoor applications (dense, high volume environments) and 5G is designed to work outdoors (cell phone coverage seamlessly follows you as you drive.)

In a perfect world, Wi-Fi and cellular would converge, and endpoints themselves would automatically select the appropriate network based on predetermined policies, such as cost or performance.

There have been some early rumblings along those lines. The Wireless Broadband Alliance (WBA) and the Next Generation Mobile Networks Alliance (NGMN) produced a report in 2021 promoting the future convergence between Wi-Fi and 5G. Similarly, the IEEE, sponsored by the Wi-Fi Alliance, has been discussing the potential pathways of convergence for a number of years.

As of now, however, true convergence seems a long way off.