Automated Frequency Coordination (AFC) is a spectrum use coordination system designed specifically for 6 GHz operation
In order for unlicensed Wi-Fi 7 (or 802.11be) devices to play nice in the 6 GHz band with the licensed users already occupying that band, the Federal Communications Commission (FCC) established Automated Frequency Coordination (AFC), a spectrum use coordination system designed specifically for 6 GHz operation that resembles similar systems in place such as the one that supports CBRS wireless operation.
When the FCC opened up the 6 GHz band (5.925–7.125 GHz) for unlicensed Wi-Fi operation two years ago, the Wi-Fi world rejoiced. The ability to leverage this new, wide band for Wi-Fi use will deliver faster connectivity speeds and improved capacity when compared to both 2.4 GHz and 5 GHz Wi-Fi. While first made available for Wi-Fi 6 operation, Wi-Fi 7 will also rely heavily on the newest spectrum band.
However, because the 6 GHz band was already occupied by incumbent users, such as fixed satellite providers, the FCC imposed some pretty significant restrictions on the Wi-Fi devices looking to transmit in this band. More specifically, to avoid potential interference with existing 6 GHz incumbents, the FCC defined two types of device classifications with different transmit power rules for Wi-Fi devices operating on the band: low power access points (APs) for indoor Wi-Fi and standard power APs that can be used indoors and outdoors.
Standard power APs, particularly when used outdoors, are the most likely to interfere with existing 6 GHz users in the area, and therefore, AFC will prove most valuable in outdoor scenarios.
LitePoint’s Director of Marketing Adam Smith shared that while the U.S. has the entire 6 GHz band available for Wi-Fi, it comes with an asterisk on it. “We operate under outdoor/indoor low-power functionality or very low indoor functionality unless you employ AFC,” he said. “In order to do standard power operation, you have to have an AFC system in place.”
Otherwise, he continued, you effectively have a “speed limit” on Wi-Fi’s highway, which impacts range and the ability to use higher data rate modes. “AFC is extremely important to take full advantage of the 6 GHz band,” Smith summarized.
In a public statement on the matter, the FCC stated: “Once per day each AFC system is required to access the Commission’s Universal Licensing System (ULS) to obtain the most up-to-date information on licensed microwave links including their transmitter and receiver locations, frequencies, bandwidths, polarizations, transmitter EIRP, antenna height, and the make and model of the antenna and equipment used.”
The Commission went on to explain that this information will be used “to determine on which frequencies and at what power levels standard-power devices may operate.”
The FCC conditionally approves several AFC systems
In early November, The FCC’s Office of Engineering and Technology announced the conditional approval of thirteen proposed automated frequency coordination (AFC) database systems in preparation for the testing phase of 6 GHz Wi-Fi operations. Specifically, the FCC approved automated frequency coordination systems proposed by Broadcom, Google, Comsearch, Sony Group, Kyrio, Key Bridge Wireless, Nokia Innovations, Federated Wireless, Wireless Broadband Alliance, Wi-Fi Alliance (WFA), Qualcomm, Plume Design and RED Technologies.
The testing process for those looking to move forward with their AFC system will include both lab testing and an opportunity for public testing, and each applicant will be required to make its system available for a specified period of time to provide an opportunity for members of the public to test each AFC system’s functionality.
Andy Davison, a senior director of engineering at Qualcomm — one of the companies to have received conditional approval from the AFC — revealed that AFC is “especially great for mesh access points” because it will enable them to communicate with each other over very high speed 6 GHz backhaul throughout a user’s home.
He described Qualcomm’s AFC system as a “complete turnkey” implementation with access point (AP) agent and cloud systems with end-to-end validation and certification. Upon official FCC approval, the solution will be available across Wi-Fi 6E- and Wi-Fi 7-based networks, and according to the company, deliver significant performance enhancements indoors, where an increase in peak transmit power of 63 times can be realized, as well as outdoors operations that are enabled with AFC.
Chris Szymanski, director of product marketing for Broadcom’s Mobile Connectivity Division told RCR Wireless News that AFC brings “the best of both worlds” by protecting incumbent license holders while allowing Wi-Fi devices to operate at maximum performance. He said that AFC will boost AP power by 63 times in 6 GHz. “We can do so much with that sort of power in terms of range, throughput and resiliency. Nothing trumps power,” he added.
According to Szymanski, Broadcom believes that most AFC-enabled APs are going to be indoor. “You need it for outdoor, but it gives you more power for indoor. What AFC is going to do is make your link reciprocal with 5 GHz. In the 5 GHz band, our customers are allowed to do more power on the Ap and the client side. With AFC, we can derive roughly the same amount of power in 6 GHz as awe can in 5 GHz, which is going to give you similar rate vs range.”
Broadcom’s customers care about whole-home, whole-premises coverage, Szymanski, adding that AFC addresses this need by making their customers’ coverage more robust.
“American businesses and households rely on Wi-Fi for work, school, access to healthcare, and connecting with friends and family,” said FCC Chairwoman Jessica Rosenworcel. “We are moving forward on our plan to open doors for next generation, faster, better Wi-Fi — including Wi-Fi 6E and laying the groundwork for Wi-Fi 7. This is good news and real progress.”
There’s a notable caveat here, though. AFC is only relevant to the U.S. This means that for those other countries that have opened up the 6 GHz band for Wi-Fi operation — like many in Europe, for instance — there is currently no such mechanism, and these low-power problems can be expected to persist in the Wi-Fi 7 era.
