Ligado Networks for several years has been waiting on FCC approval to put its lower mid-band spectrum to use for 5G, and analysts at LightShed Partners say the time is now for agency action on the L-band to help enhance 5G deployments.
Ligado in 2015 resubmitted applications to the FCC for license modification to offer 40 MHz of spectrum between 1.5 and 1.6 GHz for satellite-terrestrial use, after reaching coexistence agreements with GPS manufacturers who were concerned over interference. The proposal still faces opposition most recently from the Department of Defense, which reiterated opponents’ concerns in a letter to the FCC saying the Ligado system poses too great of risks to GPS and military operations.
In a Monday post, LightShed analysts Walter Piecyk and Joe Galone described how Ligado spectrum presents an immediate opportunity to operators Verizon and T-Mobile, could improve dynamic spectrum sharing technology expected to be deployed in 2020, and give a boost to millimeter wave and C-band spectrum.
“We believe Ligado’s spectrum can notably improve the performance of higher spectrum bands like C-Band and mmWave spectrum, based on the favorable propagation characteristics of Ligado’s spectrum. This is particularly important given that mmWave has been the keystone of the FCC’s 5G spectrum policy,” wrote the analysts, noting the view is based on discussions with operators, radio vendors, semiconductor companies and radio frequency experts.
The FCC initially pursued a millimeter wave-focused approach to 5G, with two high-band 5G spectrum auctions already completed and one slated to start next month. A pressing issue though is the United States’ need for mid- band spectrum. The FCC has promised to commence a public auction of 280 MHz of attractive C-Band spectrum by the end of 2020, but the firm voiced skepticism about the agency’s ability to do so.
“The majority of C-Band will take at least 3 years to clear and require the launch of satellites to clear existing users,” wrote Piecyk and Malone.
Specifically, the firm said Ligado could provide incremental wireless data capacity that’s needed for LTE data growth and 5G, as well improved performance of dynamic spectrum sharing, which lets operators use low and mid-band spectrum for both 5G and LTE.
“We believe Ligado could supply an operator like Verizon with at least two years of wireless data growth on a network, based on our observations of the speed at which it converted existing spectrum to LTE from 3G,” wrote the LightShed team.
“That should be an important consideration for the FCC based not only on Verizon’s spectrum needs, but also T-Mobile’s,” they added, saying T-Mobile’s capacity needs seem to be as crucial as Verizon’s when non-metro area customers are removed from the picture.
In terms of millimeter wave spectrum, which has only been deployed in limited parts of mainly dense urban areas because of its limited range, lower-band Ligado spectrum could help if it was integrated as a supplement uplink, LightShed said.
They noted there shouldn’t be any device or infrastructure ecosystem issues with implementing FDD for mmWave “even if the majority of that spectrum is being used for TDD. In fact, FDD likely offers latency improvements over TDD implementations, a key global requirement for 5G applications.”
As far as the DoD concerns, LightShed said the issues seem to be “overblown,” but added that given FCC Chairman Ajit Pai’s surprising move on C-band, it’s uncertain if he’s “willing to withstand the political heat and move forward on Ligado.
In a response (PDF) filed Thursday to the DoD letter, Ligado, which emerged following the bankruptcy of LightSquared, said the concerns raised by the DoD are not new and “the record contains ample evidence for the Commission to conclude that the assertions in the letter lack merit.”
“Notably, the implication of the DOD letter is that the most sophisticated weapon systems in the world are vulnerable to the energy generated by the equivalent of a 10 Watt lightbulb, since that is the power level Ligado has proposed for the band closest to GPS,” continued the filing. “As a matter of administrative law and spectrum policy, the DOD’s request appears to be an attempt to grab spectrum not currently allocated to it and allocated many years ago to a commercial company. Finally, the Department’s request that the Commission use a metric tied to the most minute change in background noise, as recommended in the DOT Report, would render over 200 megahertz of spectrum commercially worthless and seriously impair our ability to make progress toward 5G.”
This summer Ligado petitioned the FCC for prompt action on its license modification requests after extended holdups from the Department of Commerce.
“After bending over backwards to comply with government testing, requests, process and more process, Ligado’s application remains trapped in a web of government delays and indecision,” said Ligado Networks President and CEO Doug Smith at the time. “The result is prime mid-band spectrum languishing at a time when U.S. leadership in 5G simply can’t afford it.”
LightShed Partners reiterated the sentiment that now is the time for FCC action.
“The FCC has an easy opportunity to offer a solution that would increase the functionality of mmWave spectrum and enhance its ultimate auction of C-Band spectrum,” wrote Piecyk and Malone. “Any further delays now only threatens to delay the improvements this spectrum could offer to deploying 5G networks.”