Wireless wholesaler LightSquared says it will submit to regulators "very soon" a proposal for what to do with its "upper band", a 10MHz band that was meant to operate in tandem with its "lower" 10MHz band.
A government and industry team earlier this year found that LightSquared's original 4G network rollout plan, which featured the duo of operating frequency bands, an "upper" band closest to the GPS band, and a "lower" band farther away from GPS, caused severe disruption to GPS navigation and timing signals, primarily due to the upper band.
LightSquared in response modified its initial operating plan by removing the upper band and adjusting ground station power levels to make the lower band more compatible with GPS devices. The company did not abandon plans for the its use of the upper band, however.
"We're confident [the upper band proposal] will give comfort to GPS manufacturers and those who use GPS devices," said Martin Harriman, LightSquared's executive vice president for ecosystem development and satellite business, of the new upper band proposal during a phone call with reporters on 12 December. "We don't want to talk about until we've made it public shortly," he added.
Testing for impacts to GPS from the lower band continues, headed up by the US Air Force for the National Telecommunications and Information Administration (NTIA), which advices the White House on telecommunications issues. Those results ultimately will be sent to the Federal Communications Commission (FCC), the government agency that gave a conditional waiver to LightSquared in January. The waiver allowed LightSquared to begin building out an L-band wireless network that uses satellite signals and 40,000 ground transmitters pending verification that GPS would not be impacted.
LightSquared held the 12 December briefing to complain about what it says were the leaked results on 9 December of a new round of testing just completed by the air force. The tests, at the White Sands Missile Range in New Mexico during November, evaluated the effect of LightSquared's lower band on 92 devices, including smart phones and handheld GPS units used by many private pilots.
According to reports from Bloomberg, the final report, which will be presented to an NTIA committee on 14 December, will state that 75% of the devices "failed" when exposed to LightSquared network. LightSquared, which has the data from the tests but not the final report, said the 75% figure would mean that transmitter power levels in testing were 32-times higher than what its network uses.
"Using the LightSquared 'power on the ground' proposal, we believe that of the 92 devices that were tested, 14 exhibited a 1dB change," said the company. According to LightSquared, the testing flagged up situations where noise levels in the GPS receivers increased by 1dB or more, but the increase does not mean the device failed to operate correctly.
"This is the second leak we've seen," said Harriman. "The interpretation of the data is not yet complete. This came from someone inside the government process. It's an outrage."
The next phase of testing will start in January, when the air force will begin testing a range of high precision GPS receivers, devices that LightSquared says can be protected with new noise filters already in development. Meanwhile the US FAA has been working outside of public view with LightSquared since June on the potential impacts of the network on certified aviation units.
Harriman said the FCC should have enough information on potential impacts at the conclusion of the precision receiver testing to "make its opinion known" in the first quarter of 2012. "We firmly believe our network is compatible with GPS," says Harriman.