A proposal for in-flight broadband services in consideration by the Federal Communications Commission this week from semiconductor company Qualcomm is facing heavy opposition from the satellite industry.
Satellite service providers believe that the July 2011 proposal, which details plans to provide consumers with “anywhere/anytime broadband access” by transmitting signals from ground stations operating on the 14.0-14.5GHz spectrum band to airplanes in flight, is unnecessary and would interfere with satellite transmissions.
Qualcomm acknowledged the interference concerns and described several solutions to minimize interference in its proposal.
“The proposed Next-Gen AG system would operate in the Ku band at 14.0 to 14.5 GHz on a secondary licensed basis to, and in successful coexistence with, Geosynchronous Orbit (‘GSO’) satellite systems (used to provide various services, including Qualcomm’s own OmniTRACS service), future Non-Geosynchronous Orbit (‘NGSO’) satellite systems, NASA’s Tracking and Data Relay Satellite System (‘TDRSS’), and radio astronomy users,” Qualcomm wrote.
In addition, all ground stations “will have high antenna gain to permit aircraft to transmit at very power levels.” Aircraft will also be equipped with directional receive antennas to “reduce the GS [ground station] transmit power needs.”
However, according to the Satellite Industry Association (SIA), one of the proposal’s main opponents, “Qualcomm’s technical analysis of interference from FSS [Fixed Service Satellite] into ATG [air-to-ground] airborne stations is based on a number of unsupported assumptions.” The Satellite Industry Association represents Boeing, Lockheed Martin, DirecTV, LightSquared, ViaSat, Immarsat and many other companies.
“Qualcomm divides the VSATs [satellite ground stations] that are located within a 300 km radius of the aircraft into two groups—those that are located north of the aircraft and those that are located south of the aircraft,” the SIA wrote in a July 2012 filing.
However, “with regard to the south-side VSATs, Qualcomm assumed that many VSAT installations will be fully shadowed by other building in direction of the receiving aircraft, estimating that only 25 percent of the south-side VSATs have an unobstructed view of the aircraft. These assumptions are highly subjective and Qualcomm has provided no evidence to support its assumptions.” A large number of VSATs are mounted on roofs of buildings in urban, suburban and rural areas to give them an unobstructed view of the sky. In addition, “with respect to north-side VSATs, Qualcomm’s calculation of interference is unclear.”
The SIA also noted in its filing that “with a C/IVSAT of 6.9 dB, the forward link carrier-to-noise-plus-interference (‘C/(N+I)’) ratio would be reduced from 10.21 dB to 5.2 dB, which is only 1.2 dB higher than the minimum C/(N+I) of 4 dB required by the Ku-band ATG forward link. If the aircraft is flying over an area where the VSAT deployment density is two times higher due to non-uniformity of VSAT distribution across the CONUS, the C/IVSAT would be reduced to 3.9 dB with the forward link C/(N+I) falling to 2.9 dB, which is less than the required level of 4 dB (i.e., the forward link would be disrupted). The situation only worsens if Qualcomm were to reduce power in order to accommodate a larger, 1000-beam deployment. “
Other companies and organizations, including the National Radio Astronomy Observatory, have also raised concerns about potential interference and suggested further study is needed.
The FCC will meet Thursday, May 9 to consider a Notice of Proposed Rulemaking [NPRM].
Readers: What do you think? Has Qualcomm developed appropriate solutions to prevent interference with satellite transmissions? Or is the satellite industry correct in saying that the new ATS system will affect satellite communications?
