6 GHz readies for new users as AFC wannabees stack up

A growing roster of companies and industry groups have lined up to operate spectrum management systems for the unlicensed 6 GHz band, a key step toward putting the airwaves to use for new applications.

The deadline to submit a proposal to the FCC to become an Automated Frequency Coordination(AFC) system operator for 6 GHz was November 30. As of Wednesday afternoon, 14 had applied.  

Those include Amdocs, Broadcom, Comsearch – a CommScope company, Federated Wireless, Google, Key Bridge Wireless, Kyrio (a subsidiary of CableLabs), Nokia, Plume, RED Technologies, Sony, Qualcomm, the Wi-Fi Alliance, and the Wireless Broadband Alliance (WBA).

RELATED: FCC tees up AFC for 6 GHz band

Dave Wright, president of the CBRS OnGo Alliance and head of global wireless policy at HPE, spoke to FierceWireless Tuesday when seven applications had rolled in and estimated the tally would move safely into the double digits by end of day Wednesday.

Some of the names may seem familiar in terms of spectrum management as Spectrum Access System (SAS) administrators that handle sharing among three tiers of users for the shared CBRS band. Amdocs, Federated Wireless, Google, Commscope, Sony, RED Technologies are all involved in SAS. Nokia too has been involved, noting in its AFC application (PDF) that it's currently undergoing SAS certification. All touted their experience with SAS as adding to credibility for AFC systems.

What does AFC enable?

The FCC last year voted to unleash 1,200 MHz for unlicensed use in the 6 GHz band and in September asked for proposals for AFC operators.

AFC systems enable standard power operations by unlicensed users in 6 GHz, by ensuring incumbents are protected so new devices can use the airwaves. 6 GHz incumbents largely operate fixed microwave links, including AT&T.

RELATED: Tech giants challenge AT&T’s assessment of 6 GHz band for unlicensed use

“What standard power brings to the table is the opportunity to do outdoor operations,” which isn’t yet possible, explained Wright. The low-power indoor mode of operation for unlicensed in 6 GHz is already available in the U.S. today.

“We also can’t do anything that uses an external or convectorized antenna,” he said, meaning if a user wants to do something that has highly directional antenna coverage – also for indoors such as a stadium deployment – it can’t be done with low power indoor devices today. Finally, AFC enables any 6 GHz unlicensed applications that use power levels above 1 Watt

“If you want to do anything higher power, even indoors, then you need the standard power mode for 6 GHz unlicensed. And the only way you get that is with the automated frequency coordination,” he told Fierce.

AFC systems take into account the fixed microwave links and then only authorize the frequencies and the power levels for unlicensed users that won’t create harmful interference.

RELATED: WifiForward, WISPA tout next steps on 6 GHz

So who needs standard power operations in the 6 GHz band? A pretty broad range including anyone doing outdoor solutions, Wright said, with Wi-Fi first to come to mind. However, he also pointed to 5G NR unlicensed technologies (NR-U), so cellular RAN vendors and mobile operators, as well as residential Wi-Fi providers looking for whole-home coverage opportunities. Groups like WISPA also have pointed to 6 GHz to enable broadband in rural areas with fixed wireless.

And the list of AFC system operator applicants as of Tuesday was a “pretty good reflection of that,” with chipset makers, database providers, cable industry representatives and those with a more traditional enterprise interest all submitting applications.

RELATED: Samsung VP: Wi-Fi 6E an ‘entirely new canvas’

NTCA in a statement said it was pleased to see the robust number of applicants and also noted the range.

“As a whole, the applicants represent a wealth of industry experience in spectrum coexistence and the operation of sharing mechanisms,” the industry group stated. “NCTA looks forward to reviewing the applications and to a swift approval process that will quickly bring the benefits of standard power 6 GHz Wi-Fi to American consumers.”

Advancing the art of spectrum management

CBRS was its own foray into a unique sharing paradigm that required protecting DoD operations, establishing environmental sensing (ESC) networks along the coast and even coordination among the different SAS administrators.

Comparatively, AFC has fewer complexities, Wright explained.

“With 6 GHz automated frequency coordination, it’s quite a bit more straight forward than the CBRS SASs needed to be,” he said. “And that all comes back to the incumbents in the band you’re trying to protect.”

RELATED: CBRS Alliance marks progress on ESC networks for commercial readiness

AFC doesn’t need to deal with military radar operations used in the 3.5 GHz band, specifically Navy radar that moves along the coast and requires confidentiality with national security implications. Instead, 6 GHz incumbents provide commercial services that are publicly available in an FCC database and are largely stationary as fixed microwave links don’t tend to move.  AFC also doesn’t have to take into account aggregate interference in a given area, Wright noted. So unlike SAS providers, AFC systems operators won’t need to synchronize or exchange information with one another, he said.   

Still, there is a level of similarity. “We’re advancing the state of the art in terms of spectrum management and spectrum access with these database coordination approaches,” he commented.  

But with less complexity there’s potential for more innovation in the AFC system market.  

Market for AFC operators

While CBRS has the moniker “innovation band,” a place where 6 GHz might shine in the context of AFC systems is the opportunity for diverse business models.

In Wright’s view, there could be space for specialized AFC’s that are device specific or even application specific.

“People are going to use this for everything from outdoor to higher power enterprise to whole home residential solutions, so you could see different AFC solutions for those different niches,” he said.

RELATED: Federated close to launching ‘Airbnb’ for CBRS spectrum exchange

Companies could come out with AFC’s that are specific to their product, or he described a third-party scenario with a standard power radio to utilize as a database provider.

“I think there probably is quite a bit of room for different business models and go-to-market strategies for AFC,” he said. “And I think that there’s more room for innovation in the model for AFC than there was for SAS.”

HPE in October already announced it would use Federated Wireless to provide AFC services to enable subsidiary Aruba Network’s portfolio of standard power 6 GHz products like access points.  Wi-Fi devices utilizing the unlicensed 6 GHz band are dubbed ‘6E’. Aruba unveiled enterprise-grade Wi-Fi 6E access points in May, as the first vendor to do so, while Samsung’s Galaxy S21 Ultra was the first handset with Wi-Fi 6E support.

Standardized interface

In the application process, the FCC asked AFC system applicants a list of questions including if their AFC is based on open or proprietary software. 

Broadcom, Kyrio, and WBA’s respective AFC systems are based on open source software, while Google, Comsearch, Federated, Nokia, RED, and Sony, are primarily using proprietary.

Broadcom alongside Facebook and Cisco created a new group within the Telecom Infra Project (TIP) over the summer to develop a common reference open source software for AFC systems in 6 GHz – which the vendor and industry group-focused applicants are utilizing.

RELATED: Facebook, Cisco, Broadcom launch AFC group for 6 GHz Wi-Fi

Wright doesn’t see the distinction as making much of a difference since AFC operators are the only ones that need to access the software. In his view one key aspect to make AFC easier for device makers is broad support for a standardized interface, defined by the Wi-Fi Alliance, between the AFC system and device on the radio side.  

So far, almost all applications stated they will implement the Wi-Fi Alliance AFC System to AFC Device Interface (Amdocs application wasn’t immediately clear about use of the standard.)  

In terms of support, he said “that’s incredibly important because that will make it the de facto standard and it’s also easier for people to implement it on the device side” for things like access points and radios, if everyone is using the same standard.  

HPE colleagues were among leaders in the Wi-Fi Alliance that helped shape the interface. It will make test tools and the public trials process easier as well “because if people write tools that can query an AFC system using this standard interface, then you could use it against any AFC that supports that interface,” Wright added. So device makers won’t need to continually switch things up in testing depending on the AFC system.

HPE plans to have standard power 6 GHz devices ready for public trials in the Q2 2022 timeframe and Wright is hopeful the process through the FCC will move quickly.  

Comments on AFC system operator applications are due by December 21.