May 24, 2016–The FCC has received mixed views on Ligado Networks LLC’s request that the FCC modify its licenses, with GPS manufacturers that hammered out spectrum use agreements with Ligado generally favorable, although they criticized the metric the company uses to determine harmful interference. Some other entities, including aviation interests, raised concerns about Ligado’s request and urged the FCC to hold off acting in the proceeding. But public interest groups and competitive carriers are among those supporting the Ligado license modifications.
The comments were submitted by yesterday’s deadline in IB dockets 11-109 and 12-340 in response to a public notice released by the FCC last month seeking comments on the company’s license modifications request (TRDaily, April 22). A second public notice released the same day last month sought comments on Ligado’s call for the FCC to launch a proceeding to allocate and auction the 1675-1680 megahertz band for shared use with the National Oceanic and Atmospheric Administration. Comments and replies on that public notice are due June 21 and July 21, respectively.
In the public notice on the license modifications, the FCC sought views “on the specifics of Ligado’s proposal relating to its operations in the portions of the MSS L-band spectrum below 1559 MHz, including its abandonment of any terrestrial authorization in the 1545-1555 MHz portion, and its limiting of terrestrial operations to the 1526-1536 MHz portion of the MSS L-band under the proposed set of license conditions. We also seek comment on Ligado’s modified proposals with respect to operating in the 1627.5-1637.5 MHz and 1646.5-1656.5 MHz portions of the MSS uplink band. In addition, we invite comment on the significance to our considerations of the agreements between Ligado and Deere, Garmin, and Trimble.”
In its filing in response to the public notice, Trimble Navigation Limited expressed support for “the technical parameters and licensing conditions covering Ligado’s licensed frequencies at 1627.5-1637.5 MHz and 1646.5-1656.5 MHz and the proposed limitations on operations in the 1545-1555 MHz band, all as specified in the Modification Applications, as an integrated package and as further detailed in Trimble’s agreement with Ligado, (referred to herein as the ‘Agreed Licensing Conditions’). As indicated in that agreement, Trimble does not yet support adoption of Ligado’s proposals for use of the 1526-1536 MHz band as described in the Modification Applications, though discussions with Ligado regarding licensing conditions for that band are ongoing.”
Trimble added, “Taken as a whole, the Agreed Licensing Conditions represent a compromise which balances the competing public policy interests raised by Ligado’s (and its predecessors’) proposed use of their licensed spectrum. Given this compromise and balance, Trimble believes that it is in the public interest to grant the Modification Applications based upon the adoption of the Agreed Licensing Conditions as an integrated package.”
But Trimble added that “there are policy issues that have been the subject of extensive controversy in prior filings in the instant proceeding where Ligado and Trimble, among others, have simply ‘agreed to disagree.’ One such issue is the appropriate standard for determining whether harmful interference exists in particular operating scenarios. Trimble’s support for implementation of the Agreed Licensing Conditions does not constitute agreement with or endorsement of the assertions that Ligado has made regarding the correct metrics for determining the potential for harmful interference to GPS and other GNSS devices and applications. … Because of the complexity of this issue and the importance of the specific contexts in which it is considered, Trimble does not believe that resolution of this issue is necessary for the Commission to adopt the Agreed Licensing Conditions.
“The Commission continues to have a responsibility—beyond simply approving the applications under the parameters specified—to ensure that terrestrial operations do not cause harmful interference to GPS and other GNSS systems, and Trimble continues to believe that the established standard for determining the existence of harmful interference, whether there is a 1 dB increase in the noise floor, is the appropriate standard where the affected parties have not reached cooperative agreements on appropriate licensing conditions,” it said.
“Without application of a 1 dB decrease … standard, it would not be possible to evaluate and define whether ‘material degradation’ across a wide range of applications had actually occurred—not to mention what constitutes ‘material,’” Trimble argued. “Further, individual, unique test scenarios would need to be developed for each application. For example, certified aviation devices would require unique test scenarios for precision landing in situations in which the receiver generally has an unobstructed view of the open sky. Conversely, intelligent transportation systems would likely need a test scenario that takes into account an obstructed view of the sky and impairments from buildings and terrain. The volume of testing required across a host of subjective measures of user experience, multiplied by a plethora of test scenarios, and the vast amount of data produced would be administratively staggering—and unlikely to demonstrate any universal trend or establishment of a measurement standard.”
Garmin International, Inc., said, “The aviation industry overall has been one of the primary beneficiaries of the development of GPS, and the FCC should consider concerns raised by the Ligado Modification Applications regarding the potential impact on certified aviation devices. Ligado’s willingness to accept license conditions regarding Federal Aviation Administration (‘FAA’) issues is a positive step. Given the essentiality of GPS for aviation, where safety-of-life is of paramount concern, certified aviation devices must continue to operate on an interference-free basis. As Ligado has recognized, evaluation of any interference must be based upon technical determinations by aviation safety experts at the FAA and RTCA, Inc. Their expertise will help ensure interference-free operation. Such experienced participation is especially important given Ligado’s proposed power limit of 32 dBW (EIRP) in the 1526-1536 MHz band—a power limit which the FAA has determined raises concerns for safe operation of certified aviation GPS devices.”
Garmin continued, “The Commission’s assessment of aviation safety and development of an appropriate condition should include establishing an EIRP power limit for operation in the 1526-1536 MHz band that takes into account, and is compatible with, both current and future Minimum Operational Performance Standards (‘MOPS’) used for certified aviation devices. In particular, the method and metrics for determining a compatible EIRP limit must recognize and include a variety of factors unique to certified aviation devices and related safety-of-life applications.”
Garmin also weighed in on the metric for determining harmful interference. “Abandonment of a 1 dB standard in favor of measurements of GNSS performance based on user-perception or user-experience would produce results as numerous and varied as the domestic and worldwide uses of GNSS,” it complained. “Evaluating GNSS interference only by reference to such anecdotally-driven standards would fail to account for the need to ensure accuracy, integrity, continuity, and availability of the GNSS signal, each of which is critical to both existing and emerging applications. Moreover, failing to gauge GNSS performance based on a universal, quantifiable metric that accounts for all uses and variations in signal would quickly halt technological innovation and render design and development of future equipment impossible. In contrast, the more reliable metric that the GNSS industry long ago developed for measuring interference—a 1 dB decrease in the Carrier-to-Noise Power Density Ratio …—has allowed GPS to thrive and all GNSS systems to serve a critical role in ensuring safety-of-life services and propelling economic growth.”
Deere & Company did not file initial comments in response to the public notice.In its filing in the proceeding yesterday (TRDaily, May 23), Ligado reiterated its disagreement that a 1 dB increase in the noise floor should be used as the standard to measure a change in the functioning of a GPS device. The Roberson and Associates LLC (RAA) tests commissioned by Ligado did not use that standard. Instead, its testing was designed to gauge whether LTE signals would impact the actual performance of GPS devices and whether there would be meaningful degradation of the function of GPS devices from the perspective of end-users, according to the firm.
NovAtel, Inc., which sells GPS products, raised concerns about the testing that Ligado commissioned from RAA, which Ligado says shows that Ligado’s network can operate without disrupting GPS use. NovAtel said that “the RAA Study did not test DGPS, RTK or PPP modes and only tested for autonomous position, even in the High Precision category of receivers tested. The RAA Study is also devoid of any carrier phase based positioning analysis. Ligado has provided no explanations in its ex parte presentation or in the RAA Study for this lack of review.”
NovAtel also said “the RAA Study makes an erroneous assumption with respect to the utilization of its OEM equipment in the market,” and it said it “is particularly concerned that Ligado has moved away from what it understood to be an agreed upon standard that interference tolerance should be limited to a received interference signal power level that causes no more than 1-dB degradation …” It added that it “disagrees with the conclusion in the RAA Study that there is no meaningful correlation between a 1-dB change and GPS performance.” NovAtel also said “that there appears to be no testing of other GPS + L-band receivers” and it said that GNSS systems operated outside of the U.S. should also be tested.
NovAtel also noted the suggestion in the RAA testing report “that interference concerns could be limited by using a filtered or narrow band antenna. There is no explanation as to a program to retrofit narrowband antennas to the many existing GPS wideband receivers, how such a program will be implemented, nor who will be responsible for the expense of same. The assumption [that] only by retrofitting existing GPS receivers with filtered antenna leads to compatibility with Ligado’s intended operations ignores the practical effect of how such a program could be realized.”
A GNSS receiver component maker, u-blox America, Inc., said, “There are tens of millions of these receivers out in the field spanning several generations,” adding that “[a] big portion of the receivers are used in cost-sensitive applications where a passive antenna without any kind of SAW filtering is used. In practice it means that these applications are vulnerable to new, external interference such as Ligado although they work perfectly well in today’s environment. Retrofitting these devices is impossible. Forward-looking, new devices could be equipped with protection against out-of-band jamming; however, this would impose cost for a very cost-conscious industry.
“u-blox is investing heavily also in new market segments including V2X, ADAS, autonomous driving, emergency call systems (eCALL and ERA-Glonass), to name a few where functional safety and integrity play a vital role,” the company added. “We have a major concern that the receivers out in the field will be affected by the Ligado signals close to L1 band as they are from our receiver point-of-view in-band interference, especially where no SAW-filtering is used in the devices.” It called for “further tests to be conducted with OEM receivers …”
Topcon Positioning Systems, Inc., a provider of high-precision GPS devices, said, “The testing conducted by Roberson and Associates (RAA) on behalf of Ligado demonstrates that all three of the Topcon devices tested ‘show an impact from Ligado’s proposed operations [ ] in the 1526-1536 MHz band.’ As a result of these initial test results, Topcon and Ligado are engaged in productive discussions and working cooperatively to address Topcon’s concerns. Topcon, in cooperation with Ligado, is expeditiously preparing to undertake additional testing that will enable Topcon to better evaluate the potential impact Ligado’s proposed license modifications would have on Topcon’s devices, as well as potential mitigation efforts that Ligado and/or Topcon could implement.
“Potential mitigation efforts may involve a cooperation agreement between Topcon and Ligado that would include conditions similar to those found in the settlement agreements entered into by Ligado with Deere & Company and Trimble Navigation Limited,” the company added. “Topcon anticipates that it will be able to complete testing efforts before the Commission’s June 16, 2016, deadline for reply comments and intends to keep the Commission informed as the testing and discussions progress.”
Aviation entities expressed the greatest concern about Ligado’s planned network. “The Commission should postpone action on Ligado’s Applications to modify the ancillary terrestrial component (‘ATC’) of their licenses until outstanding work is completed to ensure the protection of certified aviation GPS receivers,” said 12 aviation industry companies and trade groups that submitted joint comments. “There remain too many unresolved issues to alleviate the aviation sector’s concerns that Ligado’s proposed operations will present an unacceptable threat of harmful interference to the aviation GPS receivers. Such interference would result in serious risks to public safety, adverse impacts to GPS-enabled operational benefits, and the loss of billions of dollars in Federal Aviation Administration (‘FAA’) and commercial aviation sector GPS investments.
“Despite Ligado’s proposed new conditions, the Joint Aviation Parties continue to submit that it would be inappropriate at this time to consider authorizing any terrestrial commercial mobile operations that may result in reduction in safety-critical GPS based functionality,” the filing added. “The introduction of downlink commercial mobile broadband operations in the 1526-1536 MHz band should follow only after sufficient study of the effects of any proposed license condition modifications is completed by the FAA. Further, the whole of Ligado’s licensed emission profile in all bands should be considered under the same concept of FAA oversight to ensure safety of aviation and the flying public, including aggregate handset emissions and out-of-band emission (‘OOBE’) limits that incorporate all unwanted and spurious emissions.”
The entities added that “Ligado’s suggestion that the Commission impose a condition on Ligado’s licenses that comprehensively subjects its emissions to specific power limits adopted by and in coordination with the continued oversight of the FAA may be worthy of further consideration. If adopted, such a condition should permit the FAA to conduct further evaluations and revise the limits over time, without further Commission intervention, as needed to maintain aviation safety.”
The groups continued, “In addition to certified aviation GPS receivers, Ligado’s Applications still raise questions about the protection of other GPS receivers used by the aviation industry for location, tracking, and system timing signals, to name several examples. Ligado’s method of testing the impact of interference to these non-certified receivers uses a non-standard approach based on key performance characteristics of a devices’ stated position accuracy. But the Commission should consider only testing that applies the well-accepted, and objective 1 dB metric as the GPS inference criterion. Specifically, the Commission should wait until the Department of Transportation completes its widely supported testing under the accepted standard before any action is taken on Ligado’s applications.”
The filing was submitted by the Aircraft Owners and Pilots Association, Airlines for America, Aviation Spectrum Resources, Inc., Bristow U.S. LLC, the Cargo Airline Association, Delta Air Lines, Inc., the Helicopter Association International, the International Air Transport Association, the National Air Transport Association, Rockwell Collins IMS, Southwest Airlines, and United Parcel Service.
The Aerospace Industries Association said it “maintains substantial concerns regarding the adequacy of the voluntary conditions Ligado offers to ensure adequate protection of avionics and GPS aviation safety equipment manufactured and used by the aviation sector, including but not limited to certified aviation receivers, other GPS devices, and satellite communications. It is critical that further evaluation of the Ligado proposed modified deployment plan be performed across the spectrum of GPS user equipment categories, for all stakeholders—civil, commercial and military—and that the FCC ensure that all aviation safety and certification stakeholders’ views are addressed.” The FCC should “defer action on this application” until the aviation industry has evaluated and weighed in on studies related to Ligado’s network, AIA said. It also said that the license modification and spectrum allocation requests should be consolidated for review by the FCC.
In its filing in the proceeding, Ligado said that its “proposed license modifications … require Ligado to operate in a manner that is consistent with all FAA requirements applicable to certified aviation GPS devices, as set out in the FAA’s Technical Standards Orders. This proposed license condition recognizes the vital role the FAA and the aviation industry must play in protecting aviation safety. This approach is consistent with Commission licensing arrangements in the L-band and in other bands requiring coordination, thus preserving the Commission’s role as Ligado’s regulator while nevertheless also ensuring a vital role for the FAA and the aviation industry.”
The Boeing Company said it “is encouraged by the progress made thus far by Ligado in collaboration with various members of the GPS industry. The agreements with Deere & Company, Garmin International, Inc., and Trimble Navigation Limited indicate that Ligado is willing and able to address the concerns of incumbent users that will be affected by Ligado’s service, and Boeing will follow with interest Ligado’s discussions with other affected GPS industry stakeholders. In these comments, Boeing highlights three matters related to the implementation of Ligado’s proposal that are not yet clear from the record and should be resolved prior to the Commission’s grant of Ligado’s applications.”
“It appears that Ligado’s network may present a risk of interference to transceivers used with the Inmarsat system, which aircraft rely on for air traffic control and other safety communications services,” Boeing said. Boeing added that “it supports Ligado’s efforts to craft a creative and self-executing solution that will provide the necessary assurance to the aviation sector. The proposal in the record thus far may ultimately, with some modifications, be sufficient. Boeing and other stakeholders, however, will require a clearer indication from the Commission that Ligado’s proposal will create effective regulatory oversight that the Commission is willing and able to implement.”
Finally, Boeing said, “Ligado has been engaged in ongoing and constructive discussion with the Aerospace and Flight Test Radio Coordinating Council (‘AFTRCC’) regarding the protection of critical flight test spectrum between 1435-1525 MHz. This discussion has produced a coordination agreement between the parties, which should resolve AFTRCC’s concerns with regard to flight test spectrum. Boeing has been participating in these discussions and supports the agreement, as well as the comments of AFTRCC on this matter.”
“While Ligado believes that the adoption of these proposed operational parameters as license conditions will address the ‘core concerns raised by the GPS Industry,’ these proposed operational parameters raise significant concerns regarding potential interference to Iridium’s MSS network in the ‘Big LEO’ portion of the L-band,” said Iridium Communications, Inc. “Following the release of the Public Notice, Iridium and Ligado have engaged in discussions to try to develop a mutually agreed upon set of operational parameters that would address Iridium’s significant concerns and allow Ligado to begin offering ATC services. The parties are currently in the process of working toward a resolution of these issues. Although, of course, there can be no assurance that one will be forthcoming, the parties are working in good faith and will keep the Commission apprised of developments. However, grant of the current unaltered Modification Applications—based on Ligado’s proposed operational parameters—would result in significant harmful interference to Iridium’s current and future MSS network.”
The Competitive Carriers Association said it was bullish on Ligado’s planned network. “Competitive carriers and American consumers alike will benefit from the Commission’s grant of Ligado’s Applications. After over a decade of building consensus among interest-holders and investing heavily in formulating new service rules, Ligado is poised to maximize efficient use of its spectrum and reinvent itself as a next generation mobile broadband services provider,” CCA said. “It is time for the Commission to bring this proceeding, along with the BDS [business data services] proceeding, to a close to ensure the United States remains a leader in 4G and leads in 5G deployments. Ligado has filed a wide body of data through which interested parties can fully address the merits of Ligado’s proposal. CCA is pleased to support Ligado in its efforts and accordingly urges the Commission to grant Ligado’s Applications.”
ViaSat Inc., said that “Ligado has aptly demonstrated the significant benefits that would flow from the availability of hybrid satellite-terrestrial technologies in the L band. The use of such technologies would create significant opportunities in both the data communications space and the positioning, navigation, and timing (‘PNT’) space. Among other things, such technologies could be leveraged to ensure ubiquitous network coverage, facilitating the availability of voice and data service throughout the United States and encouraging innovation in PNT applications and technologies. But these advances cannot materialize unless the Commission acts to facilitate more flexible uses of the L-Band spectrum proposed by Ligado.”
ViaSat noted that a 2014 agreement between it and Ligado “has facilitated ViaSat’s ability to offer managed services using L-band space segment capacity over Ligado’s state-of-the-art SkyTerra 1 satellite.”
Greenwood Telecommunications Consultants LLC said Ligado’s proposed license modifications represent “substantial improvements over the [predecessor] company’s 2010-2011 plan and proposal.” “We urge the Commission adopt orders that implement a multi-stakeholder forum (MSF) to conduct and finalize detailed L-band compatibility analysis and solutions in a timely fashion,” the filing added. “An MSF best serves needed technical scrutiny and technical solutions based on many subtle cross-service intricacies. Durable compatibility between GPS/GNSS and terrestrial broadband services is possible.”
“The Commission should approve Ligado’s applications,” Public Knowledge, the New America Foundation’s Open Technology Institute, and Common Cause said in joint comments. “Modifying [Ligado’s] license conditions and permitting Ligado to begin deployment of its proposed satellite-terrestrial broadband network should provide multiple public interest benefits and, given the agreements reached between Ligado and GPS stakeholders, satisfactorily address any lingering interference concerns. Additionally, the Commission should consider additional license conditions that will provide further public interest benefits.
“First, the Commission should permit opportunistic access to unused Ligado spectrum on a use-or-share basis to the extent technically feasible,” the groups added. “Second, the Commission should ensure Ligado and its wholesale customers abide by any privacy and network security rules the Commission has established or will establish for similarly situated services. Lastly, the Commission should make a determination regarding the appropriate standard for measuring interference. The correct measure of interference that the Commission should adopt is actual ‘harmful interference,’ which means that the interference materially degrades or disrupts the operation of the service receiving interference. Any other standard will cause valuable, useful spectrum to needlessly lie fallow.”
The National Public Safety Telecommunications Council said it “supports Ligado’s request to abandon its authority for ancillary terrestrial component operations in the 1545-1555 MHz portion of the MSS downlink band, which is consistent with previous NPSTC recommendations. NPSTC also urges the Commission to specify power levels for ATC operation that will provide ground level signals consistent with those shown in Ligado’s testing not to interfere with GPS.”
Thomas Lenard, president and senior fellow of the Technology Policy Institute, also said the FCC should approve Ligado’s license modifications. “The need for additional flexibly licensed spectrum for mobile broadband and other uses is well established and was central to the Commission’s 2010 National Broadband Plan. In the short run, the most available spectrum—indeed, the only significant block of spectrum that is already licensed [but] not deployed—is the MSS spectrum licensed to Ligado,” he said. “By approving the proposed license modifications, and thereby resolving the dispute with the GPS industry, an additional 30 MHz of flexibly licensed prime spectrum will quickly become available for mobile broadband uses. This will produce significant benefits for millions of users of mobile broadband services and for the U.S. economy more generally.
“A favorable action by the Commission in a parallel proceeding—to allocate the 1675-1680 MHz band for terrestrial mobile use on a shared basis with federal users—would allow an additional 10 MHz (1670-1680 MHz) to be productively used. In total, this would add 40 MHz of flexibly licensed spectrum—more than half the AWS 3 spectrum, which yielded $45 billion in auction revenues just last year,” Mr. Lenard added. “The Ligado spectrum is likely to yield multiples of that amount in consumer benefits.” —Paul Kirby, firstname.lastname@example.org