Every new feature that ships in the 6 GHz Wi-Fi band using the same language. You’re getting more power, more range, and more throughput. Who doesn’t like more? We all want more! Well, almost everyone wants more. The people that don’t want more are the ones that will lose something if you take it from them. In the case of 6 GHz, that’s the incumbent providers like microwave providers.

Spectrum for Rent

In order to get 6 GHz ratified concessions had to be made. One of those was that indoor 6 GHz was going to operate at a lower power level until a method of sorting out spectrum use could be formalized. That’s how we ended up with Low Power Indoor (LPI). Outdoor APs operate at Standard Power (SP) but run the risk of interfering with the incumbents who have a lot of pull with the FCC. That’s where Automated Frequency Coordination (AFC) comes into play.

AFC is the mechanism that opens the U-NII 5 and U-NII 7 bands at full power. It works because the AP uses AFC to ensure there is no interference with an incumbent source. That means knowing exactly where you are with GPS as well as the antenna height. AFC then checks a database for incumbent sources and returns allowed power and frequency use. The system then authorizes that AP to use that power level. Sounds simple, right?

APs running Standard Power are required to refresh their AFC authorization every 24 hours. Think of it like a license check or an always-online video game. If you want to play with SP APs they have to reach the Internet. Normally this isn’t an issue because most of the things we use to provide connectivity also have Internet reachability. The thing to consider is the corner cases. Because when an AP can’t be authorized it must fall back to running in LPI mode until it can be cleared again.

Design Chaos

If you’re looking at running Standard Power indoors you’re probably looking to cover large areas like warehouses or high density venues. You’ve probably worked out a design that has taken into account a lot of margins for error. You should be proud of what you’ve accomplished. But you likely didn’t take everything into account. Because AFC always gets a vote on your design. Once a day.

If you design for the best case scenario with a little fudge factor you should be good. But if there is an outage for some reason that knocks out your AFC connection or a software update causes issues with AFC you’re going to know about it in 24 hours. Your carefully designed AP plan is going to fall back to LPI power levels. That means coverage gaps and dead spots and complaining users and customers. The use case for SP indoors is a huge power increase. Some of the numbers floating around out there claim up to 63x better. Even with a healthy grain of salt you’re probably relying on using fewer APs to cover an area. If AFC goes down your right back where you started in low power mode.

Worse yet, that input happens every 24 hours. You could be perfectly fine today but there is no guarantee that the AFC will return the same power levels every time. Two APs with identical equipment could get two very different authorized power levels because one of them is two feet higher than the other. I can already see the radio resource management (RRM) system on your network going into overdrive to compensate. And if someone installs a fixed link in the area you may be permanently locked out of a band without even realizing it.

Plan Effectively

There are a lot of ifs in the scenarios above. Planning is about taking out the ifs. You can do that with some decisions ahead of time.

• Do You Need SP? – Most of the time you’re going to be just fine with LPI for standard deployments. Offices and other enterprises don’t need APs blasting Standard Power everywhere. SP really makes sense for places with big opens floors and covering campuses with a mix of indoor and outdoor usage. If you don’t need to use SP then use LPI and your life is easy.
• Ensure Connectivity – You need to make sure you’re always connected so AFC doesn’t cause problems. But you also need to make sure that your location data is up-to-date too. That means ensuring things like GPS for APs because manually entered data doesn’t get considered for AFC. If you work in an environment where you have dodgy Internet connectivity you should probably fall back to using LPI.
• Changes Should Be Minimal – SP deployments need to be more static than you realize. Every movement of an AP doesn’t just mean new RRM maps. It also means the power output and frequency use of the AP will change because of new AFC guidelines. If you have people that like to move things without considering the impact you should probably fall back to LPI or invest in industrial-grade epoxy to keep APs where they are.

Tom’s Take

One of the things I’ve mellowed about in my career is not just installing or using the newest thing because it’s the fastest or the best. There’s no need to upgrade to beta software just because it’s shiny. The same goes Standard Power in 6 GHz. If you have a need for it you should use it. Because knowing you have the need for it means you’ve already considered the challenges that come with it. You know the extra care and feeding that’s going to happen. People that just check a box to turn it on thinking that everything is going to be magically better are in for a headache that won’t easily be fixed.