How Wi-Fi 6 Has Changed Wireless Network Design Philosophy

One of the newer developments in the wireless industry is the introduction and ratification for a new PHY, called Wi-Fi 6 in marketing materials, and better known to us as 802.11ax. A new PHY means our design principles have to change; Here’s how it’s affected the status quo, and how you should compensate.

A big part of the wireless industry is simply keeping up. This can be something as simple as reading the news that comes out of the industry, or as in-depth as taking a training course. Luckily CBT Nuggets can help out with that. Check out Jeff Kish’s Certified Wireless Design Professional (CWDP-304) training for an immersive and thorough learning experience.

Addition of New Spectrum in Wi-Fi 6 / 6E: What It Means

Wi-Fi 6, or more properly, 6E, brings with it a whole new set of frequencies we can use. In the past, a lot of our problems and a big part of the CWDP curriculum was dedicated to reducing interference, channel planning and kind of felt like a giant virtual jigsaw at times. Managing channels is a pain just about anywhere but really became an ever increasing problem when you’re looking at a large enterprise environment. 

The easiest way to put it is this: The more channels you have, the better those notoriously unreliable management systems dole them out and the easier it is if you’re having to do it manually. 

This doesn’t help you if you’re running it in the legacy bands, but as the clients keep developing, it’s a giant leap forward. A new band also means that you quite simply don’t have to worry about legacy clients on it. A legacy client won’t have a radio for 6GHz, and legacy PHY isn't rated for it, so you get to avoid most of your former worries in the easiest way on your new spectral real estate by ignoring them.   

How Airtime and Utilization Benefits From Wi-Fi 6

Wi-Fi 6 alleviates a lot of the concerns that generally come about in CWDP, or even CWNA level designer courses and the practice thereafter. One aspect we often tend to ignore until it becomes problematic (which is never a good practice) is higher airtimes and utilization when designing wireless networks for a specific purpose. Addressing these factors can help reduce the occurrence of future issues.

In the legacy or current bands, there are generally one of two problems. Either the design lacks density to handle the number of clients, resulting in them being too far away from the access points, or there are legacy clients overwhelming the network with lower data rates.

Wi-Fi 6 helps with this in the same way most new PHY do: by giving you higher rates. Higher rates per transmission mean that it takes less (air)time to send the same amount of data, giving you the luxury of adding an additional client without the same degree of overhead you would have with another Wi-Fi 4 or 5 device.

If one wanted to be really clever about it, you could restrict your 2.4 to Wi-Fi 6 clients only, suddenly making it fairly useful again instead of the wholly congested band it is now. It's not in CWDP, but the author sees a large rise in 5 and 6 GHz-only networks where possible...

Wi-Fi 6: Multi-User MIMO and Bidirectional Beamforming

Wi-Fi 6 re-establishes a function that everyone somewhat hoped would come of age in Wi-Fi 5/ 802.11ac. MU-MIMO, Or (Multi-User Multiple in, Multiple Out) uses the property of reflection and multipath seen in wireless networks to send multiple streams of different information (spatial streams) to several clients at the same time, or even one client if it has a high enough need. Instead of having “diversity” where the same signal is sent multiple ways and timed to arrive contemporaneously, it’s different, discreet messages that additively can be more information that could be sent singly. 

Imagine being able to catch three balls at once, instead of being thrown each with a pause in between. OFDMA in Wi-Fi 6 adds to this by making it so that instead of a single client monopolizing the data flow (if it only needs one stream, why not use the others for other clients?) the AP can instead transmit to Multiple stations that need smaller data payloads. 

With .11ax, this theoretically can be managed at a much better resolution, slicing up the signal that’s transmitted itself as well into parts called RU, or resource units. Instead (or along with) transmitting multiple streams, each one can be cut up into the needed amount of RUs. The downside here is that it’s not really currently implemented well just yet. The most that’s really been developed so far is four divisions of a single signal, serving four clients with one transmission. 

Final Thoughts

Keep your eye on this, especially for design, as the firmware improves. Those of you with high-density deployments will discover that it enables achieving client numbers that previously seemed exclusive to marketing shenanigans. The battle is on — vendors are fighting to make the best use of this opportunity. And when vendors fight, engineers win.