There's little disagreement about what a test report expected this week will say about LightSquared's proposed LTE network: It knocks out GPS on many devices. There's far less consensus about what causes the problem and what to do about it.
LightSquared plans to build a terrestrial LTE (Long-Term Evolution) network to supplement its satellite-based mobile data system across the U.S. But to use its radio spectrum for that purpose, the startup needs to resolve interference with GPS (Global Positioning System) devices that are designed to work on frequencies close to its own. In January, the U.S. Federal Communications Commission ordered LightSquared to convene a joint working group with the GPS industry and test for possible conflicts.
The formal report on that testing was expected early Thursday. According to findings that were publicized in advance of the report, the report will show big problems: GPS unavailable to airline pilots, public safety workers, farmers, consumers and other users, over varying distances from LTE cell towers.
Along with that report, LightSquared is expected to formally present the FCC with an alternative plan that it outlined in a press release last week. That plan calls for the company to set aside half of its cellular spectrum until the worst interference issues can be resolved. But the alarming results that have already been publicized have ignited opposition to the company's whole proposition.
Some GPS vendors and users say LightSquared should be kicked out of the MSS (Mobile Satellite Service) band where it now holds spectrum. Government officials are warning that an improved air traffic control system could be at risk. Lawmakers are proposing to block some funding for the FCC unless the agency ensures there is no interference. LightSquared itself has sponsored a report that says the problem was caused by GPS devices improperly using its frequencies, rather than the other way around.
LightSquared is playing directly into the U.S. government's ambitious plans for nationwide broadband access by using satellites to reach 100 percent of the nation's population. The SkyTerra-1 satellite, already in orbit, is one of the largest communications satellites ever built. Even better for the government's goals, LightSquared wants to link that relatively low-speed satellite network with fast LTE infrastructure in cities. The LTE network is intended to reach 92 percent of U.S. residents by 2015. The service has been scheduled to launch in the second half of this year.
LightSquared gained the spectrum to do this by agreeing to build a hybrid system. However, LightSquared isn't joining those networks at the hip. It plans to sell access solely at wholesale and let its carrier partners offer service on either or both of the networks. Because this doesn't fit the FCC's original vision of a unified hybrid network, the company requested a waiver from having to sell both systems together. The price of that waiver was a requirement to solve the interference issue.
Cellular networks such as LightSquared's transmit at much higher power than do satellite-based systems -- as much as 1 billion times as high, according to some critics. In tests, the LTE network overwhelmed GPS receivers, such as in-car navigation systems, that were trying to lock on to weaker signals coming from GPS satellites. At a Congressional hearing last week, federal officials and GPS industry representatives said interference with GPS could endanger critical systems and a thriving industry. GPS device sales total $20 billion per year, and about $3 trillion worth of commerce each year relies on the U.S.-built system, said Roy Kienitz, under secretary for policy at the U.S. Department of Transportation.
One initiative that would be endangered by LightSquared is NextGen, a new air traffic control system designed to improve safety that relies on GPS, Kienitz said. The Federal Aviation Administration and airline industry have already invested $8 billion in NextGen, he said.
Given what's at stake, it's not surprising that a debate over technology has turned political. Last week, the House Appropriations Committee approved an amendment to a spending bill that would block any funding for the FCC to help LightSquared's plans move forward until all interference issues had been resolved. This effort to control the FCC through its purse strings is on its way to the full House for consideration along with the spending bill. The FCC already requires a solution to the interference problem before it will let LightSquared go forward.
"It's really just Congress reinforcing, through the appropriations process, what the FCC has already stated is their plan," said Steve Gilleland, a legislative assistant to Rep. Steve Austria, an Ohio Republican who co-sponsored the amendment.
In response to attacks from the GPS industry, LightSquared has pointed its finger in the other direction. The problem is not its LTE gear transmitting over the line into GPS spectrum, but GPS receivers going into LightSquared's frequencies when they look for satellite signals, according to a report by the wireless consultancy The Brattle Group, which was sponsored by LightSquared. Those devices should have been equipped with better filters to keep them within the GPS band, the report said.
GPS vendors and users defend their gear as government-approved and said filters could degrade GPS performance and are too expensive.
"Even if the development of filtering equipment proves technically feasible, the U.S. airline industry simply cannot afford to purchase and install it in approximately 6,600 aircraft, which would cost billions of dollars," said Thomas Hendricks, senior vice president of safety, security and operations at the Air Transport Association of America.
LightSquared's alternative plan has its own potential problems. In it, the company wants to leave aside the upper portion of its spectrum, which is closest to the GPS band, and initially launch its service in a lower set of frequencies. After a few years of testing and developing solutions to interference, it would look to expand into the upper band. Less than 1 percent of all GPS receivers use the lower band, so most would not face interference there, LightSquared said.
However, opponents question whether the lower band would be free from interference, and given what has happened so far, lawmakers and others are cautious.
"The impacts of LightSquared's revised plans should be independently and thoroughly tested to ensure the FCC does not approve plans that would introduce unacceptable risk into the aviation system, or leave aviation GPS users with new, costly burdens," said Rep. Tom Petri, Republican of Wisconsin, who co-chaired a hearing on the issue last week.
A moratorium on using the upper frequency band would probably have to be permanent, said analyst Tim Farrar of TMF Associates.
"It would be enormously expensive and disruptive for LightSquared to use the upper part," Farrar said. Losing half of its spectrum could eventually force the carrier to offer a lesser service than it hoped for, he said.
"Perhaps LightSquared thought this would be confined to a purely technical discussion. The reality is, you take on something like this, where the GPS people have enormous politically influential constituencies on their side, and you're going to end up in a nightmare situation," Farrar said.
Stephen Lawson covers mobile, storage and networking technologies for The IDG News Service. Follow Stephen on Twitter at @sdlawsonmedia. Stephen's e-mail address is stephen_lawson@idg.com
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