Ligado Networks  LLC has responded to a recent SNR Wireless LicenseCo LLC filing that raised concerns about Ligado’s request that the FCC adopt service rules and auction the 1675-1680 megahertz band. In a March 22 ex parte filing in IB docket 12-340, SNR expressed concern that Ligado’s “proposal to conduct terrestrial mobile downlink operations in the 1675 – 1680 MHz band has the potential to undermine the utility of the unpaired AWS-3 spectrum acquired recently in Auction 97. In short, the proposal has serious and negative consequences for the efficient use of the AWS-3 spectrum. These limitations were not contemplated by Auction 97 bidders like SNR; but, if they had been, there likely would have been less demand for the spectrum and less auction revenue as well.

“SNR urges the FCC to seriously consider the negative implications of the Ligado proposal for all AWS-3 licensees, and these licensees’ legitimate investment-backed expectations, before moving forward to consider Ligado’s proposal,” the filing added.

Specifically, SNR complained that an interference analysis that Ligado commissioned “does not consider the impact of already licensed commercial AWS-3 uplink operations in the 1695 – 1710 MHz band,” and an interference analysis done by the Commerce Spectrum Management Advisory Committee (CSMAC) that informed protection criteria to enable sharing between federal agencies and AWS-3 licensees “did not consider the impact of commercial downlink operations in 1675 – 1680 MHz, as proposed by Ligado.”

SNR also said that “1675 – 1680 MHz commercial downlink operations which are separated from 1695 – 1710 MHz commercial uplink operations by only 15 MHz significantly increase the probability of in-band power causing AWS-3 base station receiver overload and/or out-of-band emissions causing interference to AWS-3 base stations. This interference could create siting and interference issues that would constrain AWS-3 deployments and operations.” 

In a March 31 filing, Northstar Wireless LLC, another AWS-3 licensee, also raised concerns about the proposed Ligado deployment in the 1675-1680 MHz band, saying it “introduces meaningful challenges regarding the efficient use of this very-recently licensed AWS-3 spectrum. Northstar Wireless respectfully requests that the Commission carefully consider these complications as it evaluates Ligado’s proposal.”

Northstar said transmissions from Ligado base stations “would contribute to exceeding the allowed thresholds under the levels established by the Commission’s implementation of [CSMAC] WG-1’s proposals.” As a result, fewer AWS-3 mobile units would be able to “operate within or outside the coordination zones,” it said.

In an April 1 filing responding specifically to SNR’s filing but noting that Northstar has expressed similar concerns, Ligado said that “the technical compatibility and spectrum coordination issues identified by SNR are nothing new and have been addressed already or can be addressed during the Commission’s proceeding on service rules for the 1675-1680 MHz band.  Thus, the Commission should move forward with a Public Notice on these and related issues, as the company has proposed, so that SNR and other parties, such as Northstar Wireless … can comment in that proceeding and any legitimate concerns can be addressed in due course.”

Ligado also suggested that SNR should have known about Ligado’s proposal to use the spectrum, while also noting that the Obama administration repeatedly has proposed auctioning the frequencies.

“SNR asserts that the terrestrial use of the 1675-1680 MHz band has serious consequences for federal and commercial users,” Ligado noted. “SNR fails to mention, however, the [Ligado-commissioned] study by Alion that was prepared to address NOAA’s concerns and recommends protection zones to ensure NOAA’s earth stations used in connection with both existing and future GOES [geostationary operational environmental satellites] are not affected.  Ligado has asked the Commission to include in the service rules for the 1675-1680 MHz band appropriate protection zones consistent with the Alion study.” 

The filing added that “another defect lies in the claim that the 1695-1710 MHz uplink is separated by only 15 MHz and that will affect the probability of in-band interference.  …  SNR fails to note that there are many spectrum coexistence scenarios where the difference between uplink and downlink is 15 MHz or less. ”- Paul Kirby, paul.kirby@wolterskluwer.com