You may have seen the articles saying the FCC had pulled the plug on LightSquared's plans to use its 1.5 GHz mobile satellite service spectrum for a terrestrial LTE network. Actually, as of midnight Wednesday the FCC had yet to make that official, but a Feb. 14 letter from Lawrence Stricklng Assistant Secretary for Communications and Information at the NTIA stated "Based on NTIA's independent evaluation of the testing and analysis performed over the last several months, we conclude that LightSquared's proposed mobile broadband network will impact GPS services and that there is no practical way to mitigate the potential interference at this time."
LightSquared's waiver allowing it to build its terrestrial network was conditioned on it not interfering with GPS. If the FCC allowed LightSquared to operate its 1.6 GHz terrestrial network, it would directly contradict the findings from NTIA (National Telecommunications and information Administration), another government agency. LightSquared said the interference tests were biased against it, but now that NTIA has reviewed the results and agrees with them it will have a much harder time getting a second chance. The NTIA letter states, "since LightSquared and the federal agencies have been unable to resolve the interference issues associated with personal/general navigation and aviation GPS receivers, there is no reason for federal agencies to undertake the expense and resource commitment to test high-precision and precision timing GPS receivers at this time."
In the letter, NTIA agreed to work with other federal agencies to review receiver requirements that might make it possible for LightSquared to use the lower 10 MHz of its spectrum farthest away from the frequencies used by GPS. The letter cautioned, "Changing domestic and international aviation standards for compatible operation with signals in the lower 10 MHz may be possible, but will take many years, and retro-fitting or replacing the GPS receivers to be compliant with the new standards once they are adopted will take many more years."
An article on 4-traders.com. Falcone's LightSquared May Seek Airwaves Swap To Revive Plan by Greg Gensinger said there was a possibility that LightSquared may ask NTIA to swap some of its spectrum located further from the GPS band and used primarily for flight testing aircraft with LightSquared's spectrum. Spokespeople for LightSquared, the Defense Department and an FCC representative declined comment on such a proposal.
What impact will this decision have on broadcasters? If the FCC is unable to reallocate this satellite spectrum for terrestrial wireless broadband, it will put more pressure on them to find spectrum elsewhere, broadcast TV or broadcast auxiliary spectrum, for example. On the other side, during discussions about the viability the National Broadband Plan's recommendation to reallocate almost half the usable TV broadcast spectrum to wireless broadband, the technical problems with this plan—and the impact on the many people who still depend on over-the-air TV, either for their primary TV sets or second or third sets in other locations—was acknowledged but ignored, just as the impact of LightSquared's terrestrial use of MSS spectrum on GPS users was acknowledged but ignored until another federal agency said it wouldn't work.
With adoption of new receiver standards, perhaps one day the LightSquared 1.5 GHz spectrum can be used for a terrestrial wireless network. Achieving that will take time and money. New technology can be used to improve the efficiency of TV broadcasting while maintaining coverage, but converting to it will take time and money since the most efficient technology isn't compatible with existing TV tuners. Just as it seems unlikely LightSquared will be able to use its spectrum close to the GPS band, even with improved receivers, even with more efficient TV broadcast technology the FCC may not be able to take the 120 MHz it wants. However with enough time and money, perhaps it isn't impossible.
Doug Lung is one of America's foremost authorities on broadcast RF technology. He has been with NBC since 1985 and is currently vice president of broadcast technology for NBC/Telemundo stations.
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