Francois Rancy, director of the International Telecommunication Union (ITU) Radiocommunication Bureau since January 2011, is a veteran of many ITU spectrum wars.

He was on the front lines 15 years ago when established satellite fleet operators tried to keep would-be operators of low-orbiting constellations from using Ku- and Ka-band frequencies, claiming potential interference with satellites in higher geostationary orbit.

He chaired the 2007 World Radiocommunication Conference, WRC-07, at which the satellite sector organized itself to battle presumably more powerful terrestrial broadband networks — and won a partial victory in preserving C-band spectrum for satellite use.

WRC-15, which concluded Nov. 27 in Geneva, featured a repeat of the C-band battle. Rancy discussed WRC-15’s results.

You characterize the terrestrial allocation in the C-band bandwidth agreed to at WRC- 15 — between 3.4 and 3.6 gigahertz — as a global allocation despite the Asia-Pacific region’s disagreement. Why?

The feeling is that these Asian nations ultimately will agree to the allocation as the other regions did. There is already an attribution of this bandwidth in the Asia-Pacific. So the footnotes that were signed by individual nations do not have a regulatory import. It’s just a signal that they will deploy terrestrial in this bandwidth. The fact is that this WRC-15 decision will permit development of [terrestrial mobile broadband] terminals on a global scale in these frequencies. That’s what’s important in the end.

Was there a consensus that 3.4-3.6 GHz is not being used much by satellites now, or that satellites and terrestrial can coexist in the band?

The regulations protect the existing services. What makes things difficult is that certain nations allow satellite receive-only Earth stations without any authorization needed. We don’t know where they are and so we cannot protect them. That was the reason for the fears of the satellite community.

There are hundreds of thousands of such terminals — legally installed, providing valuable services, but unregistered, undocumented.

The fears expressed by the satellite community will be addressed by regulations protecting the ground stations. These restraints encourage nations to work together when one has an established satellite service and the other is moving to terrestrial broadband in these frequencies. The idea is to protect the frontier regions of the satellite-using nation from interference.

A big debate at WRC-15 was whether unmanned aerial vehicles could use existing fixed satellite spectrum, in Ka- and Ku-band, for command and control for long-distance flights. What was the conclusion here?

We did not give a green light for this. It’s more of a message to [the International Civil Aviation Organization] saying: You can develop norms for command and control of drones in these frequencies but we will impose conditions to protect ground services. These conditions will be fairly strict PFD [power-flux density] limits. On this basis we can begin work and it’s probably at WRC-23, once these regulatory norms have been set out, where we will complete the frequency allocation to assure that existing ground networks are protected.

Did the nations opposing this — Russia, the United Kingdom and others — have interference concerns or security concerns? For some nations, “UAV” is associated with U.S. air strikes.

Obviously there is a connotation that is, to put it diplomatically, not very encouraging. But the concern about interference with ground networks was real. This proposal began as a request for frequency allocation in all the bandwidth used for fixed satellite services today. Flying planes with the same frequencies puts into danger all the ground services already operational.

The resolution made clear that deployment was conditioned on noninterference, no?

Yes, for existing and future ground services as well. We were not going to authorize interference of future ground stations just because a few planes are flying overhead.

If the proposal had been for limited spectrum it would not have posed such problems. But its backers wanted to open 5 GHz of spectrum between 10 and 30 GHz now attributed to fixed satellite services, for broadcasting in a possibly interfering way. It was obviously an aggressive opening argument. They wanted 160 MHz, but for security reasons it would have meant opening much more spectrum than that, with the result that they were calling for multiple gigahertz. So that is the first reason — technical and economic. The second reason was of a regulatory nature: Who regulates these planes in the event of signal interference? Who authorizes their use? If we use current regulations, the regulatory authority is the nation whose airspace is being overflown. There were questions over how this would work in the case of interference: Who will have to stop the UAV from broadcasting? This remains an open question. On the other side, the PFD limits that were imposed pose the risk of being so rigid as to prevent this drone business from developing. This likely will need to be discussed again in the coming years.

Do you agree that the approval came with so many conditions that it was not a real approval?

Not a green light, no — an orange light with both belt and suspenders, so to speak.

WRC-15 opening ceremony in geneva. Credit: ITU/S. Panoussopoulos

WRC-15 opening ceremony in geneva. Credit: ITU/S. Panoussopoulos

Deployment of Earth stations in motion is a fast-growing industry on land, air and sea. That too took a lot of WRC-15 time. What was the issue?

This was a kind of regulatory card trick. There are allocations of frequency for fixed satellite services. We don’t want to create a precedent in opening it to mobile services officially because it wasn’t on the conference agenda. So the result is mixed but it was a green light for the use of these services.

Why was this approved, while the drone issue was difficult?

Because in this case we were considering a portion of the Ka-band spectrum in which there is not a lot of terrestrial service. So there is no risk of interference with this service.

It’s limited to Ka-band for the moment?

Yes, and different regions have been using different spectrum amounts for this for two decades, so why not open it for 500 megahertz globally?

So it was an approval of moving stations that could not be called mobile stations because they operate in the “fixed” satellite services spectrum?

That’s about it.

Was there any discussion of interference of geostationary-orbiting satellites by megaconstellations of satellites in low Earth orbit (LEO)?

No, just about everyone is convinced that the current regulations work. No one wanted to start again with four years of studies, which would have harmed several projects that are now under consideration. What was agreed for the agenda of future conference is PFD limits in C-band and in bands above 30 GHz.

So there is no technical fear now of interference? Some satellite operators have raised the issue.

There is no real concern over this. Some non-GEO constellation backers fear they will not find spectrum because of other LEO constellations that registered before them. But on the interference, this debate was settled after prolonged discussion 10-15 years ago. No one wants to reopen it. There was a U.S. proposal for a resolution opening the way to multilateral negotiations on LEO constellations.

How would these negotiations work?

This concluded not with a formal resolution but with a plenary session conclusion inviting the ITU to organize negotiations. It is not particularly constraining.

This is in Ku- or Ka- or both?

It’s not limited to a specific band.