LightSquared reworks network plans to avoid GPS interference

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LightSquared said it will use a 10 MHz chunk of L-band spectrum that is in the lower portion of its spectrum holdings to launch its wholesale LTE network as a way to mitigate GPS interference concerns.

The company, which has been embroiled in a fight with the GPS industry and government agencies over how much its network interferes with GPS receivers, said its proposed solution will be a way to preserve GPS and get its network off the ground. The proposed solution also comes as reports indicate that LightSquared has signed a far-reaching network-sharing deal with Sprint Nextel (NYSE:S).

Under LightSquared's proposed solution, the company will no longer launch its network in a 10 MHz chunk of its spectrum that tests showed caused interference with many GPS receivers. Instead, LightSquared said it recently inked a deal with Inmarsat, the satellite firm that controls the lower spectrum band, which will allow LightSquared to get access to the lower spectrum band sooner than it initially planned. LightSquared received approval from the FCC last week to delay until July 1 a final report on the GPS interference tests the company and a GPS technical working group have conducted.

LightSquared owns spectrum in the L-band in 1525 through 1559 MHz bands and 1626.5 to 1660.5 MHz bands, and Martin Harriman, an executive vice president at LightSquared, told FierceWireless that the company will use the channel from 1526 to 1536 MHz for the downlink. LightSquared said the proposed solution will allow it to maintain its business plan; the company has said it intends to launch commercial service in the first half of next year.

"Test results show this lower block of frequencies is largely free of interference issues with the exception of a limited number of high precision GPS receivers that are specifically designed to rely on LightSquared's spectrum," LightSquared said in a statement. "In its original plan, LightSquared planned to move into this other frequency block as its business grew over the next two to three years."

An FCC spokesman declined to comment. Jim Kirkland, vice president and general counsel of Trimble, a founding member of the Coalition to Save Our GPS, which is opposed to LightSquared's network launch, said the company's announcement "borders on the bizarre."

"LightSquared's supposed solution is nothing but a 'Hail Mary' move," he said in a statement. "Confining its operation to the lower MSS band still interferes with many critical GPS receivers in addition to the precision receivers that even LightSquared concedes will be affected. The government results submitted to date already prove this, and the study group report will also confirm this. It is time for LightSquared to move to out of the MSS band." 

In addition to using the lower spectrum bands, LightSquared said it will modify its FCC license to reduce the maximum authorized power of its base-station transmitters by over 50 percent. The company said doing this will limit it to the power it was authorized to use in 2005 and will further protect GPS receivers. Harriman said LightSquared's solution is a "sensible" one that will allow it to move forward.

In the meantime, LightSquared said it will not use the spectrum it originally planned to use for the launch of its network. The company said it will work closely with the FCC and the National Telecommunications and Information Administration, as well as the relevant U.S. government agencies and commercial GPS users, to explore "mitigation possibilities and operational alternatives" that will allow LightSquared to expand its business into the contested spectrum.

"We've spent a lot of time testing and not a lot of time analyzing what the other options are," Harriman said, referring to solutions for interference from the upper portion of LightSquared's spectrum. He said the company will have to work with filter manufacturers, look at antenna design and other options. "This solution buys some time to sit down and think through the ways" to make the upper spectrum bands useable, he said. 

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