SpaceX 'Rise Over Thermal' Interference Concerns Overblown, Gogo Says

SpaceX worries about air-ground (AG) mobile broadband service interference with its planned fixed satellite service system operating in overlapping spectrum are overblown, Gogo said in an FCC filing posted Thursday in docket 13-114. While SpaceX didn't provide details of its interference calculations, Gogo's own math claims to calculate a far smaller rise over thermal -- the ratio between the total interference and thermal noise. The Gogo filing was in response to SpaceX concerns in a filing last month about establishment of such a broadband service in the 14-14.5 GHz band as Qualcomm has proposed, with SpaceX's planned constellation also planning to use that same spectrum. Adopting a rise over thermal cap such as SpaceX is proposing "would impose an unnecessary and disproportionate level of complexity or loss of performance for the AG system" when compared with SpaceX's planned nongeostationary orbit system, Gogo said. Even if broadband service licensees were to account for as much rise over noise to a nongeostationary satellite orbit system as SpaceX claims, "the impact on noise rise would be minimal," Gogo said.