Why Is the Wi-Fi Alliance's Recent AFC Testing Event Important for 6 GHz Wi-Fi?


The development and adaptation of technology are ceaseless endeavors, pushing the boundaries of what's possible in a connected world. A recent event that stands out in this pursuit is the one led by the Wi-Fi Alliance. They gathered industry powerhouses like Broadcom, Extreme Networks, MediaTek, and numerous others for a groundbreaking Automated Frequency Coordination (AFC) Device Under Test (DUT) Test Harness event.

This collaborative event served two primary purposes. It aimed at authenticating the implementation of the test harness, and it also aimed to evaluate the readiness of 6 GHz Standard Power Devices in adherence with the regulatory norms as put forth by the Federal Communications Commission (FCC). The occasion signified a substantial leap towards the future of Wi-Fi technology, particularly Wi-Fi in the 6 GHz band under AFC control, Wi-Fi 6E, Wi-Fi 7, and beyond. But what does all this mean? Let's break it down.

Previously, I highlighted a previous significant development in the landscape of Wi-Fi. The Office of Engineering and Technology (OET), the engineering arm of the FCC, announced the conditional approval of thirteen proposed automated frequency coordination (AFC) database systems. This crucial step marked the progression towards finalizing these systems for operations in the 6 GHz band and preparing them for the testing phase. The move was welcomed as a critical stride towards faster, more efficient Wi-Fi, including Wi-Fi 6E, while laying the groundwork for Wi-Fi 7.

FCC Chairwoman, Jessica Rosenworcel, encapsulated the significance of this milestone in her statement. She emphasized the reliance of American households and businesses on Wi-Fi for an array of essential activities – from work and school to healthcare access and maintaining social connections. As such, the advancement of Wi-Fi technology is much more than a technological feat; it has significant societal implications.

During that discussion, I shed light on the two main types of 6 GHz Wi-Fi devices, as defined by the FCC. In the realm of 6 GHz Wi-Fi devices, the FCC identifies two primary categories, each with distinct transmit power rules that determine their operational settings: Low power indoor (LPI) and standard power (SP) devices. Each type serves a unique purpose and possesses defining features that set them apart.

LPI devices, as the name implies, are engineered specifically for indoor environments. They have integrated antennas and are not designed for outdoor conditions, meaning they lack weatherized enclosures. These devices operate at lower power levels and are therefore limited to indoor use. But it's precisely this power restriction that makes them so well-suited to their role. The FCC has determined that these indoor power limitations won't interfere with incumbent services. The FCC opened up the entire 6 GHz band for indoor Wi-Fi use in the United States, thus effectively expanding coverage within homes, offices, and other indoor venues. Figure 1 illustrates this expansion by showing the 1200 MHz of the 6 GHz frequency space allocated specifically for these LPI devices.

 Figure 1 - 1200 MHz of 6 GHz frequency space for lower power indoor (LPI) devices

Figure 1 - 1200 MHz of 6 GHz frequency space for lower power indoor (LPI) devices

So far, the use of 6 GHz Wi-Fi has been confined to indoor environments. What about using 6 GHz outdoors and maybe with higher power?

The FCC has also defined a class of standard power devices, which have been designed to function in both indoor and outdoor environments. However, it's worth noting that the UNII-6 and UNII-8 bands are already earmarked for mobile and fixed satellite services (FSS) utilized by the broadcast and cable industries, and therefore, are off-limits for outdoor Wi-Fi use.

Contrasting LPI devices, standard power (SP) devices bring the versatility of operating both indoors and outdoors, although restricted to the UNII-5 and UNII-7 bands in the 6 GHz frequency as depicted in Figure 2. What sets these devices apart is their ability to transmit at significantly higher power levels, expanding their reach. Further enhancing their adaptability, SP devices can utilize detachable antennas and weatherized enclosures, making them ready for a variety of environments. This crucial task of spectrum management is carried out via automated frequency coordination (AFC). Think of AFC as a proactive method to mitigate interference with existing incumbents.

 Figure 2 - UNNI-5 and UNII-7 bands in 6 GHz for Standard Power devices

Figure 2 - UNNI-5 and UNII-7 bands in 6 GHz for Standard Power devices

To elaborate, AFC systems employ geolocation databases to manage real-time frequency assignments, shielding incumbent operations from potential RF interference. A standard-power AP needs to obtain a list of permissible or prohibited frequencies from an AFC system before transmitting. This list depends on the geographic coordinates of the AP, determined by GPS or a similarly reliable method.

The effectiveness of the AFC system shines through in its capacity to establish 'exclusion zones' – specific regions where the functioning of standard power APs could potentially interfere with existing services within the UNII-5 and UNII-7 bands. This safeguarding strategy takes into consideration the presence of nearby incumbents. As illustrated in Figure 3, when an incumbent is in the vicinity, a three-dimensional AFC protection contour comes into play, curbing the transmission power of the standard power Wi-Fi AP to prevent any disruptive interference. The inclusion of an AFC system is crucial for maintaining harmony in the wireless ecosystem, particularly in urban areas with numerous incumbents.

 Figure 3 - Automated Frequency Coordination

Figure 3 - Automated Frequency Coordination

It's important to note that discussions on Standard Power 6 GHz APs and AFC often revolve around outdoor deployments, such as stadiums, a market where Extreme Networks has a long history of success. While outdoor 6 GHz Wi-Fi is essential, there's also a myriad of possible use cases for standard power 6 GHz Wi-Fi indoors.

 Figure 4 - AFC and Outdoor Stadiums

Figure 4 - AFC and Outdoor Stadiums

Based on projections from ABI Research, it's anticipated that the introduction of standard power 6 GHz devices will contribute to a surge of over 50% in total Wi-Fi access point shipments by the year 2028.

Keep in mind that FCC certification for these standard power devices is still in the pipeline - it's an ongoing process. However, the recent Wi-Fi Alliance testing event is a big deal. It brought together top dogs in the Wi-Fi world to check out how ready standard power devices are for the 6 GHz band. And guess what? With the successful run of the test harness, it's clear that we're on the right track. This event is all about pushing forward with Wi-Fi 6E and Wi-Fi 7, and making the most of the 6 GHz band, whether you're indoors or outdoors. You can read more about the event via this link.

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About the Author
David Coleman
Director, Wireless Networking at the Office of the CTO

David D. Coleman is the Director of Wireless Networking at the Office of the CTO for Extreme Networks. David is a technology evangelist, public speaker and proficient author.

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