FCC’s Approval of Ligado Networks Advances 5G While Protecting GPS

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Last week, the five Commissioners of the Federal Communications Commission (FCC), by a unanimous bipartisan vote, endorsed the expert conclusion of its engineers and their years of technical study and analysis to adopt a spectrum plan that will advance our nation’s path to 5G while protecting incumbents and especially GPS users.

The decision to approve Ligado’s plans to utilize its L-band spectrum for terrestrial applications is right on the physics, based on the facts, and firmly rooted in administrative law and the role of an independent agency. Those facts include thousands of hours of testing performed at a National Institute of Standards and Technology lab in Boulder, CO – sponsored by the Departments of Defense and Commerce – and similar testing for Ligado that my company conducted in early 2016. These tests focused on the harmful interference standard the FCC's rules use to protect GPS devices (and other wireless services) – namely whether the accuracy of GPS device functions – position, navigation and timing – would be affected by the proposed spectrum plan. The test results from the DOD-DOC sponsored lab and our efforts were presented to the Commission and showed that GPS devices would not be affected by the spectrum plan, and these tests were thoroughly analyzed in the FCC's decision.

The FCC also had in the docket and considered a study performed by the Department of Transportation – which studied not the requirement in the FCC’s rules (namely whether other spectrum usage would affect the operations of a GPS device) – but, instead, it attempted to study whether a GPS device would experience a small, largely unmeasurable change (1 dB) in the background noise environment. The FCC decision carefully analyzed each of these studies as it made its decision on the Ligado spectrum proposal.

Some of the critical protection-oriented elements of the FCC Order include:

First, it incorporates critical agreements that Ligado reached with major GPS manufacturers to reduce its relevant power levels by more than 99% to accommodate GPS devices. These agreements with the people who know GPS best, including Deere, Garmin, Trimble, and other GPS manufacturers, are proof positive that the prescribed power levels will protect their devices. The agreements are imposed on the company as license conditions, and the FCC’s approval of the Ligado Order clarifies that any violation could result in the company’s forfeiture of its license.

Second, the FCC’s Order removes a block of spectrum from Ligado for terrestrial use and thereby effectively creates a 27-megahertz “guard band” or buffer zone between GPS receivers and Ligado transmitters.  Setting aside that much spectrum – a gap larger than the entire band of FM radio channels – to lie fallow and create a guard band is unprecedented in this portion of the band. It provides evidence of the lengths that the Commission went to give GPS special protections and ensure it will be protected. 

Third, the other obligations imposed on Ligado – many applying on a 24/7 basis, to make certain its operations do not affect GPS – include various reporting and site-location requirements and a “kill switch” on the network to shut it down in the highly unlikely event of a disruption. Again, this set of requirements is highly unusual and is not imposed on any of the other licensees that operate at much higher power levels in the same proximity to GPS.

The outcome of the unanimous FCC decision provides up to 40 MHz of greenfield (immediately available) mid-band spectrum to significantly enhance the U.S.’s ability to win the race to deploy 5G while protecting GPS or other users in neighboring bands. There’s certainly no secret to the urgent need for spectrum to support our nation’s next-generation cellular efforts and especially in the mid-band where the Ligado spectrum resides.

America's 4G/LTE leadership led to the success of many new categories of companies including social media companies such as Twitter and Facebook; ridesharing such as Uber and Lyft; a much richer entertainment capability from YouTube and live-streaming platforms; more personalized means of communicating through FaceTime and WhatsApp and, more generally, content-rich Internet access through Apple or Google Android-based smartphones.

5G promises similar revolutionary changes by, first, providing much higher performance, thereby enabling, improved-user experiences and new applications not yet imagined; second, providing the capabilities to connect far more devices providing real-time sensors for critical functions in homes, office buildings or for whole smart cities; and finally, dramatically reducing latency or quickness to provide secure real-time information to/from an automobile, drone or industrial robot.

Next-generation technologies are exciting, but new applications will only be American innovations if we – as with 4G/LTE – deploy 5G first; hence, the critical and immediate need for more mid-band spectrum like Ligado’s. Leading Western equipment manufacturers (i.e., those unaffiliated with the Chinese government) have already identified the specific frequencies at issue in the FCC’s decision as important to the rapid roll-out of 5G since they pair with other airwaves – coming into the spectrum pipeline later this year – that will also promote a timely buildout of next-generation networks.   

Given all this, it is clear why FCC Commissioners came to bipartisan and unanimous agreement in reaching this decision. The ultimate result is the freeing up of mid-band spectrum critically needed for use in next-generation wireless services, while absolutely ensuring that GPS and all of its valuable military and civilian applications will always be protected. This is physics-based, fact-based, independent-agency decision making at its finest that should be supported as a great win for the citizens of the United States.


Dennis Roberson is the chairman of the FCC's Technological Advisory Council and has been a member of the council since 1999. He is executive chairman of entigenlogicTM, a research professor at the Illinois Institute of Technology, and president of Roberson and Associates, which has advised Ligado.  He previously served as Motorola’s chief technology officer.



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