Harmful Interference Likely From Global Allocation of C-Band, Satellite Operators Say

On Dec. 17, the FCC’s WRC-15 Advisory Committee (WAC) approved draft proposals for WRC-15 items. The Informal Working Group 2 didn’t reach a consensus on allocating the spectrum for wireless broadband services, so WAC/099(17.12.14) included two sides. View A (supported by the American Radio Relay League, Aviation Spectrum Resources, Boeing, CBS Corporation, EchoStar Corporation, Inmarsat, Intelsat, Lockheed Martin Corporation, New Wave Spectrum Partners, the Satellite Industry Association, Scripps Networks Interactive, SES Americom, Time Warner, 21st Century Fox and Viacom) urged no change to existing allocations for the 3400-4200 MHz and 4500-4800 MHz bands. View B (backed by Alcatel-Lucent, AT&T, Ericsson, GSMA, Intel, Motorola Mobility, Nokia Solutions and Networks, Samsung, Sprint Corporation, Telecommunications Management Group and Verizon Wireless) proposed using the 3400-3800 MHz band for international mobile telecommunications (IMT).

The WAC process determines the U.S. position at WRC-15. This debate is occurring during an ongoing spectrum auction and a proceeding involving commercial operations in the 3550-3650 MHz band in docket 12-354, said Sam Black, SIA senior director-policy.

NCTA supported introducing IMT into the band because of “the acute need for additional spectrum for mobile broadband,” NCTA said in its Sept. 12 comment. NCTA declined to comment further. Alcatel-Lucent, Ericsson, Intel, Samsung, Sprint and Verizon didn't comment. There weren’t any comments supporting View B filed at the FCC by the Jan. 16 deadline. “This may be an indicator of the interest at large,” said Intelsat Associate General Counsel Gonzalo de Dios.

C-band spectrum already is used internationally for mobile broadband and global allocation could provide potential roaming capabilities, said an AT&T spokeswoman. Appropriate equipment already exists because of the international usage, she said. The U.S. is “out of sync” with international usage, said a wireless expert. ITU allocation allows wireless carriers to design equipment for a global scale, he said.

View A doesn’t restrict the FCC from making domestic changes in C-band allocation, including the 3.5 proceeding, but is against global C-band allocation for IMT, Black said. “We’re concerned the U.S. is trying to export certain regulatory context to other places where it doesn’t make sense. If countries want to look at whether certain mobile allocation makes sense in their specific context, it’s a very different question than adding a global allocation.” de Dios said View B doesn’t include ITU-level criteria to ensure regulatory and technical protection of incumbent and future satellite systems. “The C-band is the first band that allows countries to reestablish communications when there’s been a natural disaster,” he said. “We want to ensure the sustainability of these networks.”

Global allocation of the C-band will create “widespread interference problems,” Black said. IMT transmitters will cause irreparable harm and interference to fixed-satellite service (FSS) receivers, de Dios said. Satellite distributors couldn’t provide wide coverage service without the C-band, de Dios said. Satellite operations perform better in this “unique band” when faced with rain and other adverse weather conditions, Black said. “It’s a property of physics,” he said. “The higher the frequency of the communication, the more it’s absorbed by moisture in the atmosphere. C-band is among the lower frequency ranges allocated for use by satellite communications. It’s very important especially in regions near the equator.” Other bands aren’t impervious to rain and adverse weather, so migrating satellite services to them will cause significant coverage reduction or service quality degradation, he said.

U.S. use of the C-band differs from global use, so it shouldn’t influence international policies, Black and de Dios said. U.S. fixed satellite services aren’t allowed in the 3400-3600 MHz range and their deployment in the 3600-3700 MHz range is restricted by regulations, de Dios said. Internationally “it’s a whole different ball game” because there isn’t as much differentiation of satellite usage in these bands, he said. International FSS deployments are in the 3400-4200 MHz range, he said. “[U.S.] satellite companies aren’t able to make as wide use of the lower part of the C-band as they would like to,” Black said.

Since WRC-12, the ITU studied technical realities of sharing the spectrum, de Dios said. They found that FSS and IMT stations need to be tens to hundreds of kilometers away from each other to avoid interference, he said. But that “assumes you know where FSS receivers are.” Internationally, there are many unknown FSS deployments above 3700 MHz, while there are over 5,000 known locations in the U.S., he said. The FCC suggested keeping a database of C-band receiver locations, but “it’s a challenge to put this bluntly. How do you implement this when you don’t know where the locations are?”