LightSquared Blasts GPS Receiver Quality
LightSquared today spit nails back at the global positioning system community for building shoddy receivers. In a proposal to the Federal Communications Commission revising the operational plan for its satellite-wireless broadband network, LightSquared blasted GPS receiver design:
“Legacy GPS receivers do not adequately reject transmissions from base stations operating in the adjacent frequency band because GPS receivers have been deliberately, or sometimes, inadvertently, designed or manufactured with the assumption that there would be no adjacent-band terrestrial transmissions--ignoring regulations first adopted in 2003 that permit such transmissions.”
LightSquared filed its revision proposal with the FCC today. The terrestrial portion of its network originally was to be operated on L-band frequencies adjacent to those used by GPS. The FCC, eager to fulfill an presidential directive to create nationwide broadband service, fast-tracked LightSquared in January. Tests soon indicated GPS interference, resulting in a wave of opposition from device manufacturers, the aviation and agricultural communities, and the military.
Broadcasters are also affected in that single-frequency networks and unlicensed white-space devices will coordinate through the GPS technology. Unlicensed devices--not yet deployed in the U.S. market--will operate in the spectrum between TV channels, and will locate that spectrum through the use of GPS.
LightSquared’s plan is to move to lower frequencies and use lower transmission power levels. This revised strategy was revealed earlier this month when the company acknowledged the GPS interference, and said it would launch on a lower block of spectrum controlled by Inmarsat. LightSquared said it secured an agreement with Inmarsat allowing it to roll out operations in keeping with the timeline of its original business plan and its regulatory obligation. The company said it also would modify its spectrum license to “reduce the maximum authorized power of its base station transmitters by over 50 percent.” LightSquared said the modifications would “reduce the risk of interference for 99 percent of GPS receivers.”
In its filing today, LightSquared said the remaining affected GPS receivers comprised a “small number of precision measurement and other devices” for which it would “coordinate and share the cost of underwriting a workable solution.”
If launched, LightSquared would be the first nationwide 4G LTE network with satellite coverage. It is the brainchild of New York-based hedge fund investor Philip Falcone, whose Harbinger Capital has sunk a reported $2.9 billion into the project so far. A $7 billion contract was awarded to Nokia Siemans last July
to build, operate and maintain around 40,000 cellular base stations. Sprint was brought in earlier this month in 15-year deal with a reported $20 billion, according to Bloomberg
. Deployment and operation of LightSquared would represent $14 billion in private investment over the next eight years, the company said.
LightSquared is intended as a wholesale offering for retail Internet service providers. NetTalk is the most recent ISP to sign a deal. Best Buy and other unnamed carriers have also signed up, according to TWICE
. The company is aiming to have the network operational in Baltimore, Denver, Phoenix and Las Vegas this year, pending FCC approval, which may not be the only hurdle. The House Appropriations Committee recently attached a rider to a finance bill imposing restrictions on LightSquared, according to Multichannel News
LightSquared said developing the revised operational plan had already cost it more than $100 million.
“This is a problem that the GPS industry could have avoided by equipping their devices over the last several years with filters that cost as little as five cents each.”
~ Deborah D. McAdams, Television Broadcast
Also see . .
June 30, 2011: “Can Terrestrial Broadcasting and GPS Co-Exist in Adjoining Spectrum?”
~ by Charlie Rhodes
My colleagues and I have learned a lot about interference between broadband signals into DTV receivers through our experiments in my laboratory. This knowledge led us to simulate the situation where extremely sensitive wideband receivers are overloaded by signals such as those proposed for these 40,000 base stations.