What's the big deal with Wi-Fi 7?

You'd be hard pressed to find someone who doesn't know what Wi-Fi is. After all, The Wi-Fi Alliance estimates over 42 billion devices have shipped with Wi-Fi, and most people always have multiple devices with them. Volumes have been written about the device explosion and pervasive adoption of Wi-Fi, but in a world of confusing wireless acronyms (5G, Wi-Fi 6/6E, LTE, 802.11, etc) it can be hard to determine what's what - and more importantly, what's right for you.

On January 8th, 2024, the Wi-Fi Alliance introduced the Wi-Fi CERTIFIED 7 program. Wi-Fi 7 is the next step in the evolution of the Wi-Fi standards and follows the Wi-Fi 6 (October 2018) and Wi-Fi 6E (January 2021) programs. Each of these Wi-Fi numbers loosely follows a set of standards as established by the IEEE.

*Generations prior to Wi-Fi 4 shall remain unnumbered per WFA guidance

The 802.11be standard from the IEEE provides all the technical guidance around frames (MAC layer) and physical medium (PHY layer) changes. As we consider Wi-Fi 7's readiness for the enterprise, it's a good idea to dig feature by feature through what's coming to determine if they're right for you. Largely, the new features can be grouped into three major sections:

1. Faster speeds per transmission
   1. 320MHz channels
   2. 4K QAM
2. Deterministic latency
   1. MLO (using eMLSR or MLMR)
3. More efficient use of the spectrum
   1. Multi-RU
   2. Puncturing

All culminating in some jaw-dropping promised speeds and feeds. It's not uncommon to see vendors promising data rates up to 5.8Gbps at the client and upwards of 36 Gbps at the AP! Let's investigate these a bit more in-depth:

1. Faster speeds per channel – 320MHz channels

Wide channels are a lot like driving on a 24-lane freeway with a 4-lane wide car. The vehicle is wider (consumes more lanes/channels), but you can carry more people. In this case, 320MHz channels is akin to driving a 12-lane wide car down a 36-lane highway. It sounds super awesome until you need to fit more than 3 cars (APs) on the same freeway. If you look around your enterprise, you are likely to see far more than 3 APs in earshot of you. This means that with this feature enabled, you'd run out of lanes far before you'd run out of APs. This feature is primarily meant for residential applications where a single AP will serve all your client's needs.

2. Faster speeds per transmission – 4K QAM

This translates to more bits per hertz. Simply stated, each transmission has significantly higher chances for greater fidelity at the radio receiver allowing much tighter transmissions. Greater fidelity means that we can cleanly represent more 1's and 0's to the PHY layer at once. This can dramatically increase throughput but requires very high signal-to-noise ratio (SNR) at the radio. Increasing SNR is a delicate balance between adding more APs and not raising the noise floor with channel overlap and interference. In most cases, 4K QAM is considered an opportunistic improvement when it happens, largely because the noise floor required to achieve such transmissions is unlikely to be present in typical enterprises.

3. Deterministic latency by way of MLO

Multi-Link Operation (MLO) is just that. A way for a client and an AP to communicate over multiple links with each other. These can be different radios, different spatial streams, and a few other options. When more than one link is present, a variety of latency-specific features can be achieved including redundant transmissions. MLO brings more opportunity for per-frame prioritization and, depending on spatial streams and radios available, this can bring a significant benefit.

4. More efficient use of the spectrum – Multi-RU

Multi-Resource Units (RU) is a method to increase channel width in non-standard increments (down to 20MHz). In previous standards, channel widths were increased from 20 to 40 to 80 to 160MHz (and now 320MHz in Wi-Fi 7) wide in an "all or nothing" method. Multi-RU allows us to increase to the following widths that were previously unavailable:

• 60MHz
• 120MHz
• 200MHz
• 240MHz
• 280MHz

5. More efficient use of the spectrum – Puncturing

In legacy Wi-Fi standards, when using wider channels (say 80MHz wide) and a chunk of that 80MHz becomes suddenly unavailable for a given reason (say, a RADAR pulse), the entire 80MHz channel becomes impacted despite RADAR perhaps only impacting 40MHz of that 80MHz allocation. With Puncturing, we can now remove the offending channels (down to 20MHz wide) and continue operation even if the puncture is in the middle of the 80MHz allocation.

Of course, it goes without saying that Wi-Fi 7 will require updated hardware on both the infrastructure and client sides. Wi-Fi 7 clients have been shipping in quantity since the end of 2023 and by the time you read this, it's likely that any new PC or laptop you procure will have an Intel or Mediatek Wi-Fi 7 adapter installed already. Infrastructure manufacturers are readying their solutions today with products shipping from a select few SOHO vendors and at least one EN vendor (Ruckus). It's worth noting that client adoption is expected to be a long cycle, especially on the mobile front with Wi-Fi 6E being the pervasive client technology for the following calendar year or so. It is also worth noting that Microsoft will not support Wi-Fi 7 connections in Windows 10. This means that strong alignment with your desktop and client teams will be a must when considering the Operating System requirements for adopting Wi-Fi 7 into a solution.

While not a Wi-Fi 7 specific concern, the most practical impact that you will likely have with adoption of Wi-Fi 7 will be the security requirements for 6GHz operation. If you have not yet tackled Wi-Fi 6E due to the WPA3 requirement, now is the time for you to do so. Any 6GHz operation will require WPA3 (either OWE, SAE, or .1X) and unless you have a migration strategy in place for your newer clients, this will be a significant issue for you to navigate.