Sharing is a sticky issue in the satellite business. The ability to get along with others in space or on spectrum can make or break a satellite service.
With large geostationary orbit satellites (GEOs) dominating space, the new generation of low-earth orbit systems (LEOs) such as Teledesic's must finesse their way into microgravity simply because they were not first. World telecom regulators wrote the rules for these man-made constellations when only GEOs existed. To Teledesic and other LEO systems, this regulatory structure hampers the entry and evolution of new technologies such as theirs.
Russell Daggett, Teledesic's president, said non-geostationary systems "have to protect GEOs at all times and can not get protection from GEOs. Under that regime, you could never put up a LEO system."
SkyBridge, for one, is trying. A joint effort of Alcatel Espace, Loral Space and Communications, and Toshiba, SkyBridge is building its LEO-based multimedia and interactive services network in a Ku-band, home to several GEO systems including Hughes� DirecTV, and US Satellite Broadcasting. SkyBridge's system simply switches off a satellite coming into the GEO arc, then switches it back on once it's passed through the conflicting region. SkyBridge orbits bring more than one satellite into view over a coverage area to avoid any interruption in service from a switched-off satellite.
To avoid such satellite maneuvering, Teledesic opted for political maneuvering. Bypassing the Ku-band altogether, Teledesic worked through the International Telecommunication Union to get 500 MHz of the 3500 MHz available in the still-vacant Ka-band. US delegates went to the 1995 World Radio Conference seeking one-seventh of the Ka-band, so that non-GEO systems could have a spectrum where they enjoyed priority over GEOs. "Six-sevenths of the Ka-band isn't used," Daggatt said. "No one's putting GEOs out of the band."
The US proposal, backed strongly by Teledesic, was mostly successful. Conference delegates designated 400 MHz worldwide to US services. Teledesic, the sole applicant, was granted the license to the entire band. But 100 MHz of the original US proposal was held over at the request of European countries, which asked that the International Telecommunication Union conduct studies on sharing between LEO and GEO systems. With these studies complete, delegations are heading for the 1997 World Radio Conference to decide whether the US will get the remaining 100 MHz. The conference runs from 27 October to 21 November.
Two new proposals for this spectrum pose a potential block to the US quest. One, from Japan, leaves the US with only the 400 MHz of Ka-band, returning the other 100 MHz to be shared between non-GEO and GEO services. The other, from Europe, asks that the entire 500 MHz be held in limbo until the ITU can develop specifications for LEO satellites. In essence, Europe is hoping to do for LEO services what already exists for the GEOs: set up common specifications all developers follow in their system designs to maximize the finite resource of spectrum.
Nonetheless, the consensus among delegates planning to attend the 1997 conference is that the US will likely get the remaining 100 MHz.
In issuing Teledesic the license to the spectrum in question, the Federal Communications Commission left out details about sharing the real estate with others. The issue remains vague. "We left the door open to the sharing issue, but Teledesic was the only qualified applicant at the time," said Steven Sharkey, chief of the satellite engineering branch in the FCC's International Bureau. "The Teledesic license didn't make any pronouncements about sharing and whether Teledesic must change its system [to allow sharing]. That's something we would look at later."
Observers say the FCC's actions weren't unusual. Still, that Teledesic is the first with a license when there are no rules for sharing is a bitter pill to swallow for would-be competitors. Qualcomm was so discouraged that it opted, for now, to drop its own proposal for a Ka-band medium-earth orbit system based on CDMA technology.
"We want to watch what happens with Teledesic," said a Qualcomm executive who spoke on the condition of anonymity. "So far, they're getting their own way."
But that's what usually happens to the first company to win a spectrum license: they have what amounts to control over the band, free to implement its system as it sees fit. The onus for sharing is on those systems that come later, said the FCC's Sharkey.
With Teledesic, the onus is a heavy one, said John Pientka, vice president and general manager of Motorola's advanced systems, the division developing Celestri, a Teledesic competitor. "Teledesic can only share if someone builds a constellation to interleave with their constellation. So de facto, most systems can't do it," he said
Still, Pientka is confident that Celestri will achieve detente with Teledesic in its quest to share the same portion of the Ka-band - 28.6 to 29.1 up-link and 18.8 to 19.3 down-link traffic. Motorola has built into Celestri a system called spatial diversity. This feature is geared for LEO systems, where receiving stations always see two or more satellites. This setup gives Celestri a redundancy that can come in handy in the event that one satellite overlaps with another systems' - perhaps Teledesic's - satellite.
To be sure, Celestri carries a big burden as the second Ka-bandmate to leader Teledesic, but Pientka noted that Motorola, steeped in satellite experience, has culled many lessons in sharing from its work on Iridium and from watching the Gates/McCaw venture at work. As a result, Pientka said Motorola takes nothing for granted and is taking care in courting other countries and giving them ample time to become familiar with the satellite system. As a result, Celestri enjoys a warm reception.
"Think about the position we're in," Pientka said. "We're saying frequency is open to all comers. What's not to like?"
