Automated Frequency Coordination (AFC) for 6GHz Wi-Fi
When we talk tech, it's usually at the speed of engineers. In the Wi-Fi world, the breakneck speed of innovation that we experience is nothing new. Those long-timers in the industry will remember a day when Wi-Fi was a matter of having a dedicated network for handheld scanners to have low bandwidth telnet sessions for inventory control. Fast forward through use cases such as convenience and hotspot networks, all the way to today's low-latency, high-bandwidth AR/VR applications and the only word you can't use to describe this evolution is "slow."
Unfortunately, there are times when, despite all engineering efforts put into place, this breakneck speed of adoption sometimes gets held up by things beyond our control. In wireless communications, we must abide by the rules set in our regulatory domain (here in the U.S., these are set by the FCC). By and large, the commercial, off-the-shelf solutions handle most of these concerns by automatically restricting channels and power levels that you can or cannot use. If you've ever ordered an Access Point and had to deal with a country code, this is the reason why. There are rarely regulatory domain updates, and as a consumer of Wi-Fi technologies, the last you've likely seen of anything at this scale was the update to U-NII channel allocation (in 5GHz) which occurred in 2013 (FCC 13-22 - ET Docket No. 13-49) and was the first significant change to spectrum past the initial 1997 allocation.
Since that time, engineers have maximized and optimized the 802.11 protocol to eek every ounce of performance out of the available spectrum possible. With the advent of Wi-Fi 6E however, a massive swath of additional spectrum was unlocked (more than double the existing 2.4 and 5GHz currently available to us). With 6GHz available to us now, this vast expanse of spectrum is a godsend for those of us delivering solutions over Wi-Fi, but since 6GHz was initially allowed by the FCC (April 24, 2020), we've been designing Wi-Fi with one hand tied behind our backs. These new rules for operating in 6GHz came with three notable restrictions for us here in the States:
- Restricted use of detached directional antennas
- Restricted use outdoors
- Restricted Standard Power operation
This has manifested a multi-year-long asterisk to many Wi-Fi conversations you've had since 2020 and if you've ever attempted to have a campus-wide pervasive Wi-Fi 6E network (as one example), you've been unable to do so. The main reason for this is incumbents in the 6GHz spectrum (primarily maritime and point-to-point microwave applications), and since we expect Wi-Fi to play nicely, we must have a way to see and coordinate around these existing sources of interference. Enter Automated Frequency Coordination (AFC).
AFC is a service ultimately coordinated by the FCC here in the States that provides a "check-in" service to see what channels are in use around you and what channels are safe for Wi-Fi operation. All instances of AFC are cloud-based, mandatory for 6GHz operation in the above use cases, and depending on your management solution – completely transparent.
On February 24th, 2024, the FCC announced the Operational Approval of 7 AFC systems. This long-anticipated approval means that vendors can now announce and launch external antenna solutions, standard power solutions, and outdoor products for general availability to customers. This enables us Wi-Fi designers to take advantage of the additional spectrum in places that we've been unable to up to this point with the primary goal of AFC to make sure that we stay out of the incumbent's way and represents the last slow hurdle that the Wi-Fi industry expects to run into for the foreseeable future. So much so in fact, that the IEEE and the Wi-Fi Alliance are moving full steam ahead on updates to the Wi-Fi standards including Wi-Fi 7 which will take full advantage of the 6GHz spectrum – both indoors and outdoors leveraging the new AFC solutions. Of course, once we get data from AFC on the incumbents, it will still be up to us to make sure that we are good stewards of the frequencies that we're using. Remember, AFC is not there to prevent my 6GHz Wi-Fi from fighting with your 6GHz Wi-Fi (we still have neighbors, channels, and proper Wi-Fi design to do), but fighting with those legacy users who may have a significant investment in their infrastructure shouldn't be a significant issue from here on out. Stay tuned for vendor-specific information on how you can take advantage of AFC as your vendor of choice can roll these out.