Last week, the Department of Defense (DoD) published a letter to the FCC, urging chair members to reject Ligado Network's proposal to build a wireless communication system that, according to two very different perspectives, could harm or help the United States. Ligado Networks, formerly known as LightSquared, has awaited the FCC's decision for nearly ten years now, but the proposal is still on hold.
In December of 2015, Ligado Networks filed license modification applications to adjust the ancillary terrestrial component of its mobile satellite service (MSS) license in the following three band segments: base stations in the 1526 - 1536 MHz portion of the MSS downlink band, user equipment in the 1627.5 - 1637.5 MHz band, and the 1646.5 - 1656.5 MHz portion of the MSS uplink band. Additionally, Ligado Networks decided not to use a fourth band segment, 1545 - 1555 MHz, for ATC or terrestrial base station use and proposed power and out-of-band emission limits in accordance with GPS device manufacturers. Despite these modifications, the proposal was still deemed a risk to satellite services, as the proposed frequencies are very close to those used by GPS. According to Secretary of Defense Mike Esper, “all independent and scientifically valid testing and technical data shows the potential for widespread disruption and degradation of GPS services from the proposed Ligado system."
Even with its proposal on hold, Ligado kept pushing. In May of 2018, Ligado Networks filed an amendment following the publication of the DOT ABC Assessment, reducing the maximum transmitter power of its terrestrial base stations operating in the 1526 - 1536 MHz band from 32 dBW to 9.8 dBW. In August of 2018, however, the PNT Advisory Board recommended the opposition of Ligado Network's Proposal, claiming that Ligado Network's 2018 amendment did not specify transmitter spacing or a plan for monitoring interference levels.
Ligado's Senior Vice President, Ashley Durmer, expressed frustration over Esper's recent letter to the FCC, claiming the same letter was sent to the FCC in June. And in a response to the DoD's letter, Executive Vice President Valerie Green argued, "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. 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.”
If the DoD is determined to block Ligado's proposal, then how could Ligado's network be good for the United States?
According to LightShed analysts Walter Piecyk and Joe Galone, Ligado's network could boost millimeter wave and C-band spectrum, giving the U.S. a leg-up in the 5G field. According to these analysts, the Ligado Spectrum could be used as a supplement uplink for millimeter wave spectrum, which possesses a very limited range. LightShed analysts also claim that Ligado's network could offer operators two years of wireless data growth on a network.
Whether Ligado Networks could offer the United States an advantage over China in 5G or not, the DoD's biggest concern is the Global Positioning System, which provides secure information to government and military sectors. Unfortunately for Durmer and Greene, it seems the Ligado Question may already be answered.
Sources: https://insidegnss.com/pentagon-opposes-ligados-wireless-network-proposal/, https://www.fiercewireless.com/regulatory/ligado-offers-immediate-opportunity-for-fcc-verizon-t-mobile-analyst?fbclid=IwAR2rSVmvVf1BGpt2NehAM6M0Leq87vixDtKwekw1aRoBg_agmFhzzXq53Uw