Skip to main content

Report Cites GPS Interference as LightSquared Pitches Plan B

GPS advocates were saying a just-released report essentially spelled doom for a novel wireless network plan, while the company that has invested billions in the proposed network was pitching plan B.

LightSquared would provide a wholesale 4G wireless net that cable operators and others could use to add branded wireless to their bundles.

"The LightSquared Terrestrial Broadband Service Will Cause Harmful Interference to Nearly All GPS Receivers and GPS‐Dependent Applications." That is one of the conclusions in a summary of the just-released FCC working group report on tests of LightSquared's proposed next-generation hybrid 4G wireless network.

The FCC had granted LightSquared a waiver to build the terrestrial network using satellite spectrum, but conditioned it on not interfering with GPS devices on adjacent spectrum. The FCC saw, and still sees, LightSquared as one way of addressing the spectrum crunch/deployment gap in wireless broadband. so long as the interference issues can be resolved.

LightSquared got a two-week delay on the June 30 release of the report--the FCC working group included representatives of both LightSquared and the United States Global Positioning System Industry Council (USGIC)--and in the meantime  pitched the FCC on a compromise approach--it filed the plan with the commission Thursday--that would employ spectrum less adjacent to GPS and at reduced power levels.

Conceding that early tests indicated that the 10 MHz block of spectrum it planned to use for its initial nationwide launch did pose that interference risk, the company said it was proposing going to that plan B.

It will use an alternative block that it says "greatly reduces" that risk and is located further away from the GPS frequencies, and will not use the original block that caused so much outcry until and unless the FCC gives the go-ahead.

In addition, the company said that it will reduce its base station power by more than 50%, "which will provide additional protection to GPS."

"This is a solution which ensures that tens of millions of GPS users won't be affected by LightSquared's launch. At the same time, this plan offers a clear path for LightSquared to move forward with the launch of a nationwide wireless network that will introduce world class broadband service to rural and underserved areas which still find themselves on the wrong side of the digital divide,'' said Sanjiv Ahuja, LightSquared chairman and CEO in a statement.

USGIC does not see it that way.

"Based on the overwhelming evidence of incompatibility between LightSquared's proposed 4G LTE terrestrial broadband service and GPS receivers and GPS‐dependent applications in the adjacent band, the only feasible option is relocation of LightSquared's terrestrial operations from a satellite spectrum neighborhood to one that is better suited for terrestrial operations," the group said in summarizing the findings.

Various government agencies have also raised concerns about the interference to GPS, including the Department of Commerce.

FCC Chairman Julius Genachowski has been high on the idea of the wholesale broadband net since at least last summer. When the project was announced, he said it represented "more than $7 billion of new investment, with the potential to create more than 100,000 new private-sector jobs within five years. Today's announcement shows that FCC policies are helping grow the U.S. economy by catalyzing investment and job creation," he said.

FCc spokesman Neil Grace said the FCC would study the working group report carefully and resolve any interference concerns the commission has.

"The Commission appreciates the hard work the working group has contributed to this report. The FCC has a long-standing record of resolving interference disputes based on engineering data. As is customary, the agency's expert staff will now conduct a thorough and expeditious review of the report. As Chairman Genachowski has said before, we will not permit LightSquared to begin commercial service without first resolving our concerns about potential harmful interference to GPS

devices," he told B&C/Multi. "Nevertheless, our nation cannot afford to let spectrum go underutilized. America's economic growth and global competitiveness are on the line. The Commission is confident in the public process underway designed to determine whether LightSquared's mobile broadband offering can coexist with services provided by GPS for the benefit of our nation."