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'Rusting' Dishes

Fixed Satellite Should Share Spectrum, Say Google, Mimosa, New America

The FCC should allow fixed wireless service to share the 3700 MHz-4200 MHz band with the incumbent fixed satellite service (FSS) because the satellite users are underutilizing the band and are doomed to lose that spectrum anyway, said speakers from Google and rural wireless ISPs. The comments came at a New America Foundation-hosted event in support of a petition for rulemaking in June by the Broadband Access Coalition (see 1706210044). “If the military can learn to love sharing, the satellite industry can, too,” said Michael Calabrese, director of the Wireless Future Program at New America. “It’s better than losing it.”

A wireless service sharing the same band as the FSS is practical because 500 MHz of spectrum are available to use, a larger span than numerous other wireless bands combined, Calabrese said. The band is underutilized, with many satellite dishes pointed at a few satellites, he said. Spectrum sharing with the military has been successful even though it requires keeping track of mobile radar to avoid interference, but sharing with FSS would require avoiding interference only with fixed earth stations, a much easier task, Calabrese said. “The satellite folks are not thrilled by this.” The Satellite Industry Association didn't comment.

Most of the FSS use of the band is for transmitting video from broadcast sources, said Dynamic Spectrum Alliance President Kalpak Gude: Video business “dynamics” are changing, and FSS customers are less likely to agree to the very long leases of satellite time that are common practice in the industry. “The challenges for satellite are growing,” Gude said, expressing doubt that FSS entities will be able to retain access to the 3700 MHz-4200 MHz band. Sharing the spectrum could make FSS more attractive to government regulators, and access to spectrum is “critical” for that industry, he said. Sharing the band is more practical than “clearing it out” using a mechanism like an incentive auction, Gude said. “Sharing starts with protecting the incumbent.”

Sharing is “powerful” but should be done using “cognitive radios” that would allow smart devices to avoid interference by moving to different bands, said ViaSat Spectrum Architect Peter Flynn. Such a technical solution would allow smoother sharing than relegating satellite use to a small portion of the band, Flynn said.

The 3700 MHz-4200 MHz band hits a “sweet spot” for providing wireless broadband because it propagates through barriers such as trees well, said Rise Broadband co-founder Jeff Kohler. It also doesn’t propagate too far in the clutter layer of urban areas, making it practical for providing last-mile service to buildings that aren’t wired for fiber, said Google Spectrum Engineering Lead Andrew Clegg. WISPs typically operate on several bands, and the 3700 MHz-4200 MHz would be a useful “tool in the chest” Kohler said.

The 3700 MHz-4200 MHz spectrum also would allow last-mile service to rural areas where building fiber infrastructure isn’t economically viable, said Mimosa Networks CEO Brian Hinman. With more spectrum, more options for broadband service would be available in more places, Hinman said.

Available data on the FSS use of the band is old and inaccurate, Clegg said, saying 29 percent of the dishes in the existing database either don’t exist or aren’t located where their listing claims they are. The first step in creating the new wireless service would be to obtain accurate data of the current use of the band, said Clegg and Hinman. Clegg’s figures don’t include situations where an abandoned dish is located in the right place but unused and “rusting,” he said. “I suspect there are a significant number.”