Looking ahead: The spectrum-sharing debate continues

It's clear that the concept of spectrum sharing isn't going away anytime soon. But what's not clear is how the concept might be applied to future spectrum bands.

That's a concern for mobile operators like AT&T and T-Mobile because they prefer to have exclusive access to their spectrum holdings. They don't want to share them with anyone.

But getting exclusive access to new spectrum is becoming increasingly difficult as demand for spectrum continues to rise, coming not only from the 5G industry, but also other commercial and government areas.

A key element in the debate: whether the US military will release the lower 3GHz band for commercial uses. And if so, how.

The rise of CBRS

Spectrum-sharing scenarios aren't necessarily new, but they received a jolt in 2019 when the FCC finally opened the 3.5GHz CBRS spectrum band for commercial uses. The band employs an innovative sharing technology that allows commercial operators to use the band when the US Navy doesn't need it. Sharing is managed by a system of sensors that communicate with spectrum databases, which can shift commercial users away from spectrum when the US Navy is using it.

However, the 5G industry isn't keen on the CBRS band.

"A review of today's CBRS marketplace shows that CBRS does not live up to the hype as the foundation of innovation and should not be a model for future spectrum policy," analyst Roger Entner, of Recon Analytics, said in a CTIA release last year. CTIA is the main trade association for 5G network operators.

"Real-world studies show low utilization, low market demand, and a dearth of innovative use cases," Entner added.

That argument sparked angry responses from CBRS proponents, including some cable companies, which are currently using the band or hope to use it in the future.

Sharing gets noisy

Amid the debate over CBRS, some policymakers are hoping to push spectrum sharing into other bands.

For example, an NTIA report released in May found that the number of CBRS devices grew by 121% over a 21-month period. That could give leverage to players supportive of spectrum sharing, including the US military.

Then, in September, a new study from Spectrum for the Future outlined the economic benefits of spectrum sharing. The coalition includes cable industry backers. Their position also has implications for the US military and how the US Department of Defense (DoD) might handle the release of the lower 3GHz band.

But the biggest development in spectrum sharing involved the release of the Biden administration's new national spectrum strategy via the NTIA, the government agency charged with handling federal usage of spectrum.

"Next-generation Wi-Fi networks, large satellite constellations in low Earth orbit, rapidly increasing space launch cadences, aggregated data transfer requirements, 5G and 6G broadband networks, private wireless networks, autonomous vehicles, and other advanced systems drive demand," according to the NTIA's spectrum strategy. "Dynamic spectrum sharing is one key to meet these growing demands."

Waiting on the lower 3GHz band 

The 3.1GHz-3.45GHz band pits the US military and the US wireless industry directly against each other. That's because the military currently operates radar and other functions in the lower 3GHz band, but the wireless industry wants to get access to the band for 5G.

According to CTIA, policymakers need to release the band for 5G so that the US can stay competitive on the international stage.

The DoD recently issued a report on whether the lower 3GHz band can be used for 5G. However, that report hasn't been released publicly. Nor does it paint a straightforward picture.

"I think the tricky part there is what we are seeing from our colleagues at DoD is that that portion of spectrum is not readily available today ... you can't share it now and use it ... and we have real work to do to be able to meet the conditions where we could do more sharing, but we're not ready to give up on it, and we want to do that hard work," said NTIA Director Alan Davidson at a recent Congressional hearing.