Details are starting to trickle in about how exactly some of the biggest winners in the FCC's recent Rural Digital Opportunity Fund (RDOF) auction plan to construct their networks in order to meet their buildout obligations.

Some are heavily embracing the use of expensive fiber connections and planning to use wireless technologies sparingly.

For example, the chief executive of LTD Broadband – the top winner in the RDOF auction with a total of $1.3 billion in funding – told Light Reading the company's network buildout will rely almost exclusively on fiber.

"We're doing GPON [Gigabyte Passive Optical Networks]. We believe that fiber is a 40+ year asset and is largely future proof to provide 10 and 100Gbit/s in the future over the same glass we're putting in today," LTD CEO Corey Hauer wrote in response to questions from Light Reading. "We might use some multi-gigabit-capable licensed links to do some middle mile where fiber might be a challenge to place. But for LTD Broadband the overall network including last mile will be 99.9% fiber. Our design will include physical diversity, so we'll likely leverage wireless in some areas to give us a redundant path to our fiber."

Hauer said the company would use 11GHz, 80GHz and 70GHz spectrum for the 0.1% of its network that would rely on fixed wireless.

"I know there are a lot of folks throwing stones at the idea of doing gigabit over fixed wireless. We are not one of those stone throwers. But for LTD Broadband, we believe that fiber represents a better choice for our RDOF obligation areas," Hauer added. He did not respond to additional questions on the topic.

Auctioneers for the digital divide

Hauer's comments are noteworthy considering LTD cited plans to use fixed wireless and fiber for 1 Gbit/s services in its "short-form" application for the FCC's RDOF auction, which is designed to finance the construction of telecom networks in rural areas. The FCC's RDOF proceeding last year was a reverse auction where companies and entities that submitted the lowest bid for covering a particular area won – however, now they're on the hook to cover that area with broadband services. Bidders also selected the speeds they believed they could provide, ranging from 25 Mbit/s to 1 Gbit/s.

All of the companies that participated in the RDOF auction filed short-form applications listing the bare-bones basics of their network-buildout plans. Winners in the auction were required to file their "long-form" applications – which provide the exact details about how they plan to meet their obligations – with the FCC last week. An agency spokesperson said the FCC is currently reviewing those documents and will release them publicly at a later date.

A number of legislators, trade associations and others are calling on the FCC to carefully review those long-form applications over worries that winners – particularly those using fixed wireless technologies for 1 Gbit/s services – might not be able to meet their obligations.

"Though theoretically possible, it is highly questionable how a responsible design could deliver financially viable gigabit wireless service in rural areas, using current technologies (whether at midband or mmWave frequencies)," wrote trade association NRTC in a lengthy filing with the FCC.

The association said it has worked with several rural utilities across the country to design and deploy wireless networks. NRTC said its analysis showed that a fixed wireless network running in 80MHz of spectrum in the 5.8GHz band could profitably achieve 100 Mbit/s services but not 1 Gbit/s services.

A hybrid approach

Some RDOF winners might disagree with those findings.

"We want to put in as much fiber as possible," acknowledged Alexander Hagen, CEO of Etheric Networks. The company won $248 million in RDOF funding to build connections to thousands of locations across mountainous parts of California.

However, in a document the company shared with Light Reading, Etheric explained it expects to deliver 1 Gbit/s and 500 Mbit/s voice and broadband connectivity using a hybrid approach that relies on a combination of dark fiber and fixed wireless technologies in licensed and unlicensed midband and millimeter wave (mmWave) spectrum. The company said it has assembled sufficient licensed spectrum to provide gigabit services using licensed spectrum to more than 90% of the locations within its RDOF footprint, and would cover the remaining 10% with a combination of fiber and unlicensed spectrum.

"We are pretty confident we can execute," Hagen told Light Reading, adding: "We think we can do this build within this budget." Hagen said the company is looking for extra funding in order to finish its buildout efforts in two years instead of the required six.

Hagen said Etheric's network design would use portions of the 5G standard for core network functions like authentication and potentially billing. But other parts of its network, including actual wireless transmissions in bands like the 60GHz band, might use other standards such as Facebook's Terregraph offering.

"5G is a toolkit. It has all kinds of pieces in it," Hagen said, explaining that Etheric plans to use only the pieces that make sense.

Hagen added that Etheric is evaluating hardware and software suppliers including Tarana Wireless, Samsung, Ubiquiti, Siklu, Cisco and Arista.

Finally, Hagen said Etheric may be able to construct a carbon-neutral network using solar-powered basestations and electric vehicles. He said the company already operates three solar-powered basestations today.

Ethernic isn't the only company planning to rely on wireless technologies to meet its RDOF commitments. For example, Nextlink won $429 million in the RDOF auction and recently announced an agreement with tower giant American Tower to use up to 1,000 cell towers to broadcast fixed wireless services across 11 states ranging from Illinois to Louisiana to Nebraska to Wyoming to Wisconsin. To be clear though, Nextlink plans to rely on a mix of fiber and fixed wireless. Meantime, fixed wireless provider Starry, which won $287 million in RDOF funding, did not respond to questions from Light Reading about its buildout plans.

Windstream, Charter embrace fiber

"In RDOF, we don't believe fixed wireless was the right technology," Windstream CEO Tony Thomas told FierceTelecom. The company won $523 million in the RDOF auction, and plans to rely on fiber to meet its obligations. "We're not confident, given the topography, that fixed wireless would have been a good solution. And there are also technical limitations in fixed wireless on the upload speed."

Thomas continued: "We speak of that being someone who's spent extensive time and energy investing in fixed wireless technology. I think we have a very well informed view around the capabilities of fixed wireless."

Thomas also told Telecompetitor that Windstream doesn't expect its RDOF winnings to cover the entire cost of its rural buildout. Charter recently disclosed similar financial calculations, noting its own $1.2 billion RDOF winnings might only cover a quarter of the full cost of its overall buildout project.

One more angle to the fixed wireless discussion involves wireless transmissions from space. SpaceX's Starlink, from billionaire Elon Musk, won $886 million in the RDOF. The company recently disclosed that its beta service already counts 10,000 users in the US and abroad. Nonetheless, some have questioned whether the startup can meet its own RDOF obligations.

But Starlink's early successes could spell concerns for some fixed wireless providers, according to some in the industry.

Related posts:

— Mike Dano, Editorial Director, 5G & Mobile Strategies, Light Reading | @mikeddano