LightSquared Provides Solution for GPS Interference Issue


on June 21, 2011   |   4 comments

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A few days ago, LightSquared’s ambitious 4G LTE network project was stopped by the FCC because of dangerous interference with existing GPS networks. LightSquared aspired to cover the US with an LTE network for wholesale leasing. However, a report by GPS industry leading companies and federal organizations had incriminated LightSquared’s project because it affected GPS signals used for air navigation, military purposes and many other applications. As a response, LightSquared was supposed to deliver its own report a few days later but demanded an additional two-week delay to come up with a solution.

The problem lay in the fact that LightSquared intended to deploy its network by using a 10-MHz frequency block of spectrum that was too close to the ones used by GPS receivers. LightSquared’s signals were going to be sent out at full power to ensure the quality of the service. However, this made the radio waves extend in neighboring bands occupied by GPS signals, thus causing the interferences. LightSquared thought that it would not be confronted regarding this issue because it had worked on reducing the leaking of the radio waves on close bands. Also, LightSquared previously used the same spectrum for its Satellite-to-Earth transmissions without any issues. These transmission are, however, by necessity very low power and did not create the problems that were raised when the FCC allowed LightSquared to build a national mobile network on those same wavelengths.

LightSquared acknowledged the situation and proposed a straightforward solution. It will deploy its network on a different 10 MHz frequency band which it had already negotiated with Inmarsat but was supposed to start using only in three to five years. The wannabe operator has also offered to cut its signal transmission power by half so as to prevent any interference with close spectrums. This proposition seems to provide a solution to the current issue, however, it makes the whole implementation of the project a lot more difficult. The alternate spectrum was supposed to be used only in a few years to cover new customers. And LightSquared’s signals are still said to affect several GPS signals even on lower power and different bands. Contesters to the project will not be satisfied with this solution, Jim Kirkland, CEO of Garmin, one of the concerned GPS manufacturers, said about the proposed solution: “This latest gambit by LightSquared borders on the bizarre [...] LightSquared’s supposed solution is nothing but a ‘Hail Mary’ move.”

The next few days will be decisive for the future of LightSquared’s 4G LTE network and might be a hard blow to the deployment of LTE technology nationwide.

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