WASHINGTON — The U.S. Federal Communications Commission is asking for more input on how to expand the use of C-band spectrum predominantly used by satellite operators.

The request, issued May 3, suggests it is increasingly unlikely that the agency will make a decision in the first half of the year as satellite operators had previously expected.

The FCC said the comments it has received since July 2018 when it voted to open the band for next-generation 5G wireless signals generated even more questions about how that spectrum would be repurposed.

Those questions “raise additional issues concerning the Commission’s authority to employ elements of those mechanisms,” the FCC said.

The FCC has not decided on using a “market-based” approach like the plan promulgated by the C-Band Alliance, a spectrum auction (favored by T-Mobile, Google and others), or a hybrid of the two. The agency has also yet to decide how much of the 500 megahertz of downlink spectrum to repurpose.

As the FCC decides how to progress on C-band, it now wants new comments on how enforceable satellite operator’s rights to interference protection are against terrestrial signals with “co-primary” access.

The FCC is also asking if those rights should be linked to C-band operators that have customers in the U.S. that need protection from signal interference. The four members of the C-Band Alliance — Intelsat, SES, Eutelsat and Telesat — have such customers, but other operators with at least partial C-band coverage of the United States do not.

Satellite operators ABS, Hispasat and Embratel Star One have petitioned the FCC to ensure any spectrum transition plan compensates them as well despite lacking U.S. C-band customers, since they will no longer be able to market that U.S. C-band capacity.

In a statement to SpaceNews, the C-Band Alliance said it will continue to discuss the C-band transition with the FCC.

“We look forward to responding to the Commission’s inquiries and working cooperatively to build consensus from the many stakeholders involved,” the C-Band Alliance said. “We are convinced — and have received significant support — that our proposal is the best suited way to achieve both protection of the incumbent services to millions of US television households and an efficient clearing of C-band spectrum to enable an accelerated deployment of 5G in the US.”

Another area the FCC seeks comment is on is how enforceable interference protection rights are for network operators with receive-only satellite dishes, particularly since those one-way dishes can’t cause interference.

T-Mobile suggested to the FCC that new terrestrial C-band signals would function undisturbed by satellite signals, but would cause interference to satellite dishes on the ground. FCC wants more assessment of T-Mobile’s conclusion and what impact that should have on the agency’s work.

“The Public Notice’s purpose is to increase clarity on several topics as the FCC continues its work on the C-band clearing proceeding,” the C-Band Alliance said. “Clearly, interference protection of satellite services is a key consideration.”

The FCC’s comment window lasts 45 days following publication on the Federal Registrar — 30 days for initial comments and an overlapping 45 days for reply comments.

Executives from Intelsat and SES, the two companies that have rights to more than 90 percent of C-band downlink spectrum in the U.S., said recently that they no longer have a sense of when the FCC will decide on how to open up the spectrum.

“The FCC controls the timing of the order, be it a month from now or later this year,” Intelsat CEO Stephen Spengler said during an April 30 earnings call. “Regardless, we are completing all of the work necessary to implement our proposal the moment the FCC issues an order.”

SES CEO Steve Collar said April 26 that early timelines look less promising. “Sitting where we are, Q2 seems unrealistic,” he said.

FCC Chairman Ajit Pai said in March that the agency is more interested in making the right decision than a rushed one.

Both satellite executives said they have been using the time to explain the C-Band proposal more openly to their customers and other involved parties.