LightSquared shifts spectrums, salvages its 4G network launch

Written by on June 23, 2011 in AM/Medium Wave, On Regulatory & Spectrum - 4 Comments
Print Friendly

gps-networkLightSquared apparently has dodged a GPS bullet that almost shot it down before it started up. It will switch to another spectrum that virtually eliminates interference with Global Positioning System receivers.

Early tests by the Reston, Va., 4G network provider indicated that one 10-megahertz spectral block of its Long Term Evolution (LTE) open wireless broadband network severely interfered with GPS receivers. Unfortunately, the block in question happened to be the set of frequencies that LightSquared planned to use to launch its network.

Company engineers subsequently determined that another 10-megahertz block of the spectrum did not create such interference. This company had reserved that alternate block as an area for expanding its service as business grew. Instead, the block will become the company’s primary set of airwaves.

The company had come under fire from GPS users, including U.S. military, fire and safety agencies, various wireless device manufacturers, and farm equipment manufacturers. Most of those complaints seem to have been resolved by the frequency switch. The Federal Communications Commission had given LightSquared till July 1 to come up with a solution. The FCC must approve the final business plan.

LBA has expertise in resolving a wide variety of interference problems in wireless, broadcast, medicine, and industry.   Contact Mike Britner for immediate assistance.

As part of the revised plan, LightSquared will modify its FCC license to reduce the maximum authorized power of its base-station transmitters by more than 50 percent. This will limit the network provider to the power it was authorized to use in 2005, which will provide additional protection to GPS.

LightSquared negotiated with Inmarsat, the satellite company that controls the new block of spectrum in the L Band, to speed up its use of the frequencies. An agreement will allow the company to proceed on schedule, introducing commercial service by 2012.

“This is a solution which ensures that tens of millions of GPS users won’t be affected by LightSquared’s launch,” said said Sanjiv Ahuja, LightSquared Chairman and CEO. “At the same time, this plan offers a clear path for LightSquared to move forward with the launch of a nationwide wireless network that will introduce world class broadband service to rural and underserved areas, which still find themselves on the wrong side of the digital divide.”

LightSquared and the FCC agreed last year on conditions that will let it offer service to as many as 100 million Americans by the end of next year and 260 million by 2016. The company will sell wholesale access to its network to other companies, which in turn will rebrand the services.

The company’s SkyTerra 1 satellite was launched in November from Baikonur Cosmodrome in Kazakhstan by a commercial satellite launch service. Built on a Boeing platform, the satellite features a 22-meter L-band reflector-based antenna and is designed with an estimated lifetime of fifteen years. It will hover above the United States to provide wireless coverage to 100% of the U.S. population.

4 Comments on "LightSquared shifts spectrums, salvages its 4G network launch"

  1. Don Williams June 24, 2011 at 10:34 pm · Reply

    Pilots will tell you that GPS is being used to replace precision IFR approaches and provide new ones. This is a big part of modernization of the air traffic control system. Loss of signal in these cases is a bit more than an inconvenience, it could be fatal, and it could be said statistically, WILL cause fatalities. LightSquared has been more concerned with their potential profits than the impact on other services. I think their plan is to dump revenue into this project so it will quickly become to big to stop. The FCC seems more concerned with supporting a lucrative business than managing the spectrum in a responsible manner. This has gotten the attention of quite a few congressmen….

    b1. FCC ‘recklessly fast-tracked’ LightSquared waiver


    By AOPA ePublishing staff

    With reports surfacing that LightSquared’s proposed broadband communications network negatively interferes with GPS, 66 members of Congress
    weighed in June 7, saying that the “FCC has recklessly fast-tracked the waiver process without undertaking appropriate review procedures.”

    In a letter to FCC Chairman Julius Genachowski, the members of Congress requested that the FCC “only approve LightSquared’s waiver if it can be
    indisputably proven that there will be no GPS interference.” They also acknowledged the commission’s call for a working group to investigate and
    report on the issue by June 15.

    Congress, along with the aviation industry, believes the FCC should have required that the proposal be tested before granting a waiver instead of
    approving the waiver with a plan for later testing. LightSquared is proposing to use a satellite spectrum that is close to the one used for GPS.

    The letter quoted Air Force Space Command Gen. William Shelton on the impact that is currently being observed in testing: “Within three to five
    miles on the ground and within twelve miles in the air, GPS is jammed by those towers… If we allow that system to be fielded and it does indeed jam
    GPS, think about the impact. We’re hopeful we can find a solution, but physics being physics, we don’t see a solution right now.

    “LightSquared has got to prove that they can operate with GPS and we’re hoping the FCC does the right thing.”

    Like or Dislike: Thumb up 0 Thumb down 0

  2. Wal Sakaluk June 25, 2011 at 10:36 pm · Reply

    Good sense finally prevailed.

    This interference issue would not have occurred if due diligence was applied at the planning stage. A hard lesson was learned for some. The licensing authorities have a lot to answer for regarding this faux pas.

    The spectral slot that was reserved for expansion is now LS’s initial service launch slot. How then will they accommodate expansion? Wait and see I guess.

    While on the subject of interference, has anybody else reading this experienced interference to C-band satellite services from terrestrial Wimax sources?

    Like or Dislike: Thumb up 0 Thumb down 0

  3. Ed Reid June 27, 2011 at 10:38 pm · Reply

    Sounds like they are moving forward with the switching to another frequency and maybe in the near future our GPS devices will have a better filtered front ends..

    Like or Dislike: Thumb up 0 Thumb down 0

  4. HIPAR June 28, 2011 at 2:05 pm · Reply

    So they are ‘Home Fee’? I don’t think so. Evidently, everyone concerned with avionics wants a lot more testing to determine if their proposed accelerated activation of the LTE lower channel and power reduction ‘fix’ is really a fix.

    According to the RTCA that lower 10 MHz is OK for to GPS receivers to track and provide position. But, some receivers are expected to have difficulty acquiring GPS signals when the lower 10 MHz is active.

    Then there are those pesky precision users with only 0.5% of the receivers. Like it’s OK to put the farmers, surveyors and geo-reference scientific users out of business because that’s a small group with a weak voice.

    What if Inmarsat can’t expeditiously juggle it’s channels to clear the way for Lightsquared? Will they have legal problems if Deere/JPL StarFire corrections cannot be accommodated?

    We can only guess what Lightsquared does to military P code and the new M code .. weapons systems vulnerability is classified.

    — CHAS

    Like or Dislike: Thumb up 0 Thumb down 0

Leave a Comment