FAA Modeling Could Cap Ligado Transmit Levels Well Below License Ask
Though Ligado wants a cap on the transmit equivalent isotropically radiated power (EIRP) levels for the thousands of its planned satellite-broadband LTE network base stations at 32 dBW at most, realistically they would operate at power levels of half of that or less, the company tells us. Those even-lower power levels still would be within parameters for the company to provide 5G and IoT service with its L-band spectrum, said General Counsel Valerie Green.
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In an ex parte filing to be posted in FCC docket 11-109, Ligado recapped a meeting between Green and Wireless and International bureau and Office of Engineering and Technology staff to discuss operating parameters in the 1526-1536 MHz band. Ligado said its ongoing work with the Federal Aviation Administration toward a condition that would protect certified aviation GPS operations resulted in a model to determine transmit power limits. The firm said it agreed to set transmit EIRP power levels for each tower based on that model, with none of them exceeding 32 dBW. Green said the company is working on modeling but the EIRP range for all its towers as projected by the model would end up being "substantially lower" than 32 dbW. Ligado has said it expects to deploy between 10,000 and 20,000 towers in its ground-based network (see 1609090052).
When it sought FCC approval in 2015 to use the ancillary terrestrial component part of its L-band spectrum, Ligado set an EIRP limit for the 1526-1536 MHz band of 32 dBW -- down from the 42 dBW it set in its original 2012 application. Green told us the company is waiting for the FAA to conclude its analytics so work then can commence among Ligado, the FAA and the FCC on creating conditions that would include the EIRP limits.
Ligado urged the FCC to approve its LTE plans (see 1702270037) and the Technology Policy Institute agreed. In an ex parte filing posted Thursday, President emeritus-Senior Fellow Thomas Lenard said the FCC's "inability ... to resolve the Ligado-GPS interference problem reflects a regulatory failure stemming from the lack of clearly defined priority rights and a market mechanism for buying and selling those rights."
Lenard said neither the L-band nor GPS band had rights that would have provided a route to occupants of the adjacent bands being able to work out a deal, though Ligado and GPS users "overcame these deficiencies." Pointing to last month's release of a National Advanced Spectrum and Communications Test Network report on Ligado's LTE plans and the effect on GPS (see 1702160056), Lenard said the FCC has "enough information now to approve the license modifications without harming adjacent GPS users." Green said the company has no sense of when the FCC might act. The agency didn't comment.