LightSquared presented the FCC with an amended version of its LTE network plan designed to further assuage the concerns of the GPS community over interference. The filing was made as LightSquared came under withering criticism at a congressional hearing over its planned wholesale network.
In the filing, LightSquared proposed two significant modifications to its plan, which has already been modified from the company's original proposal. Under the latest version, LightSquared still plans to use the lower 10 MHz chunk of its L-Band spectrum, but will now limit the power of its base stations on the ground to -30dBm when it launches its network.
According to a LightSquared official who spoke to reporters, that power level, as measured 50 meters from the base station, will not degrade the performance of GPS devices. In fact, in tests only two GPS receivers were operating above that threshold and their performance was not degraded. The official said that LightSquared's operational performance and business plan will not be affected by the change. By 2015, LightSquared will increase the power level to -27dBm and by 2017 it will increase it to -24 dBm.
In addition to the change in power, LightSquared also proposed a solution for satellite-augmented GPS, which is used for precision GPS devices from companies such as Trimble and John Deere. LightSquared suggested permanently using a 4 MHz chunk of spectrum for those services which will provide them with a stable satellite signal. That proposal will give LightSquared time to develop a filtering solution for precision GPS receivers, and the company is looking at antenna replacement or a module modification for legacy precision GPS receivers.
The LightSquared official said so far the reaction from the GPS community has been mostly positive. The FCC has said there is no timeline for a decision on LightSquared's plan, but the LightSquared official expressed confidence that a decision will be made soon.
The Coalition to Save our GPS, a group of GPS device manufacturers opposed to LightSquared's network, said in a statement that the newest plan "appears to be a positive step toward reducing, for some devices, the harmful interference to GPS signals confirmed during testing of LightSquared's earlier incomplete proposals."
However, the group said the plan does not claim to solve interference to high-precision GPS receivers, and that further testing is needed. "To be clear, this proposal may be headed in the right direction, but there are still many questions and many concerns to many users," the coalition said. "The quite harmful impacts interference to GPS would cause users must be responsibly, constructively, and completely addressed before LightSquared moves ahead. Even after three tries, there remain substantial gaps in what LightSquared has offered."
The new modifications to LightSquared's plan came as federal government officials said before Congress that more testing of the company's plan is needed. The testimony included that of Mary Glackin, a deputy under secretary at the National Oceanic and Atmospheric Administration as well as Anthony Russo, director of the National Coordination Office for Space-Based Positioning, Navigation and Timing, which coordinates federal agencies' interest in GPS.
Additionally, Republicans slammed the FCC for giving LightSquared a conditional waiver that allowed its wholesale customers to deploy terrestrial-only devices. The FCC mandated in the waiver, however, that all GPS interference concerns be resolved before LightSquared could start operating its network.
LightSquared signed a 15-year, $9 billion network-hosting deal with Sprint Nextel (NYSE:S) in late July, but the deal is contingent on LightSquared getting FCC approval to operate its network.
- see this LightSquared FCC filing
- see this Washington Post article
- see this IDG News Service article
- see this Broadcasting&Cable article
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