LightSquared Tests Spectrum Sharing

WASHINGTON – LightSquared is testing the feasibility of sharing spectrum with federal users. The bankrupt venture won approval from the Federal Communications Commission recently for experimental authority to test wireless broadband at 1,675-1,680 MHz on a shared basis with existing federal meteorological users. The authorization reflects a November, 2012, petition filed by LightSquared to operate the terrestrial component of its proposed network in this 1.6 GHz allocation rather than the 1,545-1,555 L-band spectrum where its operations were found to interfere with global positioning systems.

“LightSquared proposes that this additional use of the 1,675-1,680 MHz band be permitted only if such use is coordinated to protect government systems that will remain in the band-including the critical weather monitoring and predicting operations of the National Oceanic and Atmospheric Administration,” the petition stated.

Speaking Wednesday at an investors’ conference in New York, outgoing FCC Chairman Julius Genachowski said he expects LightSquared to eventually win approval to use its spectrum for a terrestrial broadband network, according to Bloomberg.

It was under Genachowski’s watch in January of 2011 that LightSquared secured an FCC waiver allowing it to develop a terrestrial operation in the L-band spectrum designated primarily for satellite transmissions. The company’s goal was to create a nationwide 4G LTE hybrid terrestrial-satellite wireless broadband network to offer on a wholesale basis to consumer-facing carriers.

Subsequent tests indicated that terrestrial signals interfered with GPS devices in adjacent spectrum, or rather, GPS devices lacked the ability to reject LightSquared’s signals.

LightSquared offered to operate at a lower power level on only half of its spectrum, creating a buffer zone for GPS operations, but further tests by the National Executive Committee for Space-Based Positioning, Navigation and Timing Systems Engineering Forum indicated that high-precision GPS devices—such as those used by the military—would still be affected.

LightSquared countered with its own test results from Alcatel Lucent, and offered to fabricate filters for sensitive GPS devices, but the outcry from the GPS community was overwhelming. Comments continue to compile on the FCC’s LightSquared docket, even though the commission suspended the terrestrial waiver more than a year ago.

Within a few months, the company, funded with around $3 billion from New York-based hedge fund Harbinger Capital, filed for Chapter 11 in U.S. Bankruptcy Court for the Southern District of New York. Lawmakers followed with a hearing on how LightSquared secured the terrestrial waiver in the first place, and have since turned their attention to receiver standards.

LightSquared’s current proposal, and the subject of the experimental authority, is to initiate a rulemaking to add a non-federal, terrestrial mobile use allocation to the 1,675-1,680 MHz band. If granted, LightSquared would use the 1,670-1,680 MHz band for downlinking, and two more 10 MHz allocations in the 1.6 GHz band for uplink operations. It would relinquish its authority to conduct terrestrial operations at 1,545-1,555, “providing GPS receivers an additional 10 MHz guard band from terrestrial services,” the petition states.

The next step would be a Special Temporary Authority to determine the technical feasibility, timing and cost of moving radiosonde devices to other frequencies.

The experimental license commenced April 29 and expires July 20, 2013.