he world’s major satellite-fleet operators – and some of their biggest customers like the U.S. Department of Defense – will begin a four-week battle Oct. 22 to protect their access to 800 megahertz of precious radio spectrum tha t

has been the exclusive preserve of the satellite industry for years, but now is coveted by terrestrial wireless broadband companies.

At stake, satellite industry officials say, is the continued functioning of hundreds of thousands of satellite transmission

 networks that currently

 enjoy unencumbered use of the C-band radio spectrum from 3.4 to 4.2 GHz.

Claiming that their expected growth rates justify the demand for more spectrum, backers of WiMax and other terrestrial wireless broadband technologies want the rights to enter that spectrum even though they concede that coexistence with satellite signals is 

impractical in many cases.

The issue will be decided by the World RadiocommunicationConference (WRC), a quadrennial gathering of almost all the world’s nations organized by the United Nations’ International Telecommunication Union. The WRC-07 conference is scheduled to take place Oct. 22-Nov. 16 in Geneva.

Going into the meeting, representatives of the two sides agreed that the United States and most of the other nations in the Americas are

backing the satellite sector’s demand that so-called IMT technologies – broadband terrestrial wireless – be kept out of C-band. Africa appeared divided. Russia and China are backing the satellite side, as are most Southeast Asian nations. However, Japan and South Korea – where satellite C-band is

 used little and where several large terrestrial wireless communications hardware builders are located – want the IMT technologies allowed in C-band.

India, who operates satellites in C-band, is undecided.

European governments are offering what might 

be the strongest opposition to the satellite sector’s position. The European Union has called for IMT technologies to be allowed in the lower half of the portion of C-band that is under debate – 3.4 to 3.8 gigahertz – so long as measures are taken to protect existing satellite services.

Backing the satellite sector’s position are satellite-fleet operators Intelsat, SES, Inmarsat, Asiasat and a group of eight non-profit industry associations. Pushing to open the C-band spectrum are some of the largest cellular-network operators aligned with hardware builders including Nokia, Ericsson, Siemens and Motorola.

Intelsat of Bermuda and Washington, the world’s biggest satellite-fleet operator, estimates that 60 percent of its current in-orbit capacity is in C-band. SES of Luxembourg, the second-largest fleet operator, estimates that 44 percent of its global fleet is in C-band, mainly on satellites operated by the company’s SES Americom and SES New Skies divisions.

The world’s biggest mobile satellite services operator, Inmarsat of London, says its global fleet relies on C-band for its satellites’ feeder links and for telemetry data on satellite health.

Industry officials estimate that some 160 telecommunications satellites functioning today in geostationary orbit are equipped with C-band capacity.

If the satellite sector is to be believed, the consequences of IMT’s entry into C-band would be catastrophic. Ripple effects would flow onto launch-service providers, satellite manufacturers and teleport operators.

Despite this, the WRC-07 meeting’s approach has gone relatively unnoticed. The publicly traded stock of SES and Inmarsat has not been under pressure. An official at NASA, which has spectrum issues related to Earth observation satellites that the agency will be

defending at the WRC, said the WRC debate is occurring “unbeknownst to most of the rest of the world.”

“A lot of people think C-band is yesterday’s technology, that we’re all moving to Ku- and Ka-band,” said Kalpak S. Gude, vice president for regulatory affairs and deputy general counsel of Intelsat. “It’s not true. C-band continues to grow for us and in some places in the world, such as Africa, it is the main band for video distribution.”

John Lothian, vice president for space development at SES, agreed. “There is a misconception that C-band is dying. In fact it is growing. But this WRC is perhaps the first of several battles with terrestrial wireless technologies. Bandwidth is scarce, and there are signs that in the future even our use of Ku-band will be under threat.”

The U.S. Department of Defense is lined up on the satellite operators’ side of the argument for two reasons: The U.S. military is a heavy user of commercial C-band satellite capacity, and it also operates shipborne and other radars that use C-band.

European governments, most of which favor allowing IMT technologies into C-band, argue that the coexistence with satellites can be managed so that the satellite signals are not blown away by WiMax and other broadband terrestrial transmissions.

“The satellite operators are not always as flexible as they could be,” said Eric Fournier, director of spectrum planning and international affairs at the French National Frequencies Agency.

In an Oct. 19 interview, Fournier said France – which has invested more in satellite development than any other European government – understands that in some areas WiMax and other IMT technologies cannot operate in the vicinity of satellite Earth stations without wiping out the satellite signal. But he said satellite operators do not need as much of the C-band spectrum as they claim, and that the IMT technologies can be introduced in ways that protect existing satellite installations.

“We have a large Inmarsat station located in Aussaguel,” Fournier said. “Don’t you think we want to protect it? Of course we do and we will. You have to look at this case-by-case. Depending on the geography of the region in question, you could have IMT and satellites coexisting in adjacent spectrum bands.”

Peter B. de Selding was the Paris bureau chief for SpaceNews.