LightSquared has submitted a significant new offer to the U.S. Federal Communications Commission in its bid to use frequencies near the GPS band for a cellular data network.
In a filing to the FCC on Monday, the fledgling carrier offered to accept an extra check on the most troublesome part of its spectrum. It also offered to postpone an increase in power for its network and eliminate a further power boost from its road map.
LightSquared wants to operate an LTE (Long-Term Evolution) mobile data network around the U.S. on frequencies it has licensed that are close to those used for GPS (Global Positioning System). But before the FCC will let it launch the network, which it hopes to do by the end of next year, the agency needs to be satisfied that the system won’t interfere with the use of GPS receivers.
The new proposals should help to ensure that LightSquared’s initial LTE launch won’t affect GPS receivers and reassure GPS vendors and users that a later expansion of the system would be fully vetted with their interests in mind, said Jeffrey Carlisle, LightSquared’s executive vice president for regulatory affairs and policy.
Testing earlier this year showed that using the upper 10MHz of LightSquared’s spectrum crippled many GPS devices. Subsequently, the carrier limited its plans, for now, to a lower band that is farther from GPS frequencies. Test results on that band are set to be discussed on Wednesday by the National Executive Committee for Space-Based Positioning, Navigation, and Timing (PNT ExComm), though some information about the tests was leaked last Friday. On Tuesday, LightSquared criticized that leak and questioned some conclusions drawn from the data.
With a forecast of about nine months from approval to commercial launch, LightSquared will need a green light from the FCC fairly soon to launch by the end of 2012. More testing is due to start in January. The new offer, if accepted by the FCC, might move that process forward more rapidly.
“This is part of the package and we expect that it will be a significant set of proposals in order to move this in the right direction,” Carlisle said.
LightSquared has committed to launch its base stations at a power level on the ground of -30 dBm (decibels per milliwatt). It currently plans to increase its maximum power to -27 dBm after Jan. 1, 2015, and to -24 dBm after Jan. 1, 2017.
In Monday’s filing, the company said it will not boost the radios’ maximum power to -27 dBm until after Jan. 1, 2016, and will eliminate the later increase to -24 dBm.
Cellular radios with lower power would be less capable of affecting GPS. LightSquared says that at these levels, it believes the LTE network will not degrade the performance of GPS devices, at least if the LTE network is operating in LightSquared’s lower spectrum block.
Also in the filing, LightSquared addressed the conditions under which it could be approved to use the upper block of its spectrum. The company proposed a double control over that block, in which not only the FCC but also the PNT ExComm would have to give the green light for operation on those frequencies. The PNT ExComm is the federal agency overseeing GPS, and it works through the NTIA (National Telecommunications and Information Administration), which coordinates the use of all federal government spectrum.
“What we want to do is say, ‘Let’s put more process around it … that genuinely and clearly defends GPS interests in the use of that spectrum,'” Carlisle said. “Whatever happens to this upper 10MHz, the 10MHz of spectrum closest to GPS, the GPS community has a direct and decisional voice in it.”
Stephen Lawson covers mobile, storage and networking technologies for The IDG News Service. Follow Stephen on Twitter at @sdlawsonmedia. Stephen’s e-mail address is firstname.lastname@example.org