Little Common Ground Seen Between Rival C-Band Proposals
The 3.7-4.2 GHz band will play a role in deployment of 5G, speakers agreed Friday at a New America event, but they jousted over whether the C-band could be cleared in only some geographic areas and complained about lack of clarity and technical details on the two main plans for terrestrial access to the band. Top priority must be preventing harm to incumbent users, and there needs to be far more detail about the Broadband Access Coalition (BAC) and Intelsat/SES/Intel proposals before an evaluation can start, said American Cable Association (ACA) Senior Vice President-Government Affairs Ross Lieberman.
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NCTA, NAB, NPR and ACA want to see a lot of questions explored in the draft C-band NPRM to be released next week. In a docket 17-183 filing Friday, they cited about four dozen issues they said they hoped the NPRM would address. They include asking for details on interference mitigation, how the FCC could expedite resolution of interference issues, feasible alternatives to C-band for itinerant services, and whether exclusion zones would be needed around C-band earth stations in a sharing scenario and how big.
Michael Calabrese, director of the Wireless Future Program at New America, said the NPRM likely will tee up two "potentially complementary" proposals, but there was little sign of a happy medium being struck that accommodates both.
BAC's C-band sharing proposal would protect satellite operations by using fixed point-to-multipoint services, never pointing antennas in directions that would interfere with fixed satellite service (FSS) dishes, said Google Spectrum Engineering Lead Andy Clegg. But mobile service is inherently difficult to coordinate with FSS, he said. He said many Americans have 20 or fewer FSS earth stations within 100 kilometers of their homes, meaning sizable populations where point-to-multipoint service makes sense. He said the current push to get unregistered C-band earth stations to register with the FCC could show there are so many in operation that point-to-multipoint service wouldn't work either, he said, but "I kind of doubt it."
Using C-band for terrestrial mobile would require relocating FSS operations out of some frequencies to avoid those interference issues, Clegg said. He said one potential direction is relocating FSS services from 100 MHz of C-band just in urban areas, using the rest of the band for underlay services, while rural areas use all 500 MHz of the band for co-channel operations with FSS. A fixed wireless point-to-multipoint underlay deployment would require some minor FCC rules tweaks and deployment, but likely could be done on the same timescale or faster as Intelsat/SES is claiming for clearing, he said.
That C-band is underutilized "could not be farther from the truth," and counting earth stations is an overly narrow approach, said Intelsat Vice President-Spectrum Strategy Hazem Moakkit. He said the Intelsat/SES/Intel band-clearing plan “avoids bureaucracy” and is the fastest route to access the spectrum for 5G. He criticized the BAC spectrum sharing plan, saying that given the weakness of satellite downlinks, any adjacent noise would be akin to "a frat house next door," he said. Moakkit and Clegg also locked horns about how well FSS operations can accommodate fixed adjacent band operations.
Mimosa Networks Chief Technology Officer Jaime Fink said there's sizable satellite use of the C-band, but there's also underutilization. He said clearing the band isn't feasible and a focus should be on dynamic sharing.
“Linear television is dying,” meaning there are ample routes for moving video content through alternative means and finding the least amount of spectrum needed for incumbent users, said Chris Wieczorek, T-Mobile spectrum policy director. He said rural remote areas require C-band, but metro areas don't have that need. He also backed an incentive auction approach and freeing up more C-band: "100 MHz in the 5G world is just not a lot.” Countered SES outside counsel Michele Farquhar of Hogan Lovells, it's tougher to do an incentive auction for C-band than it was for TV broadcast space since C-band is shared among satellite operators. Replied Wieczorek, the 600 MHz band was very much shared.
Others criticized the idea of clearing in some areas but not others. Lieberman said lopping off the 50 largest markets would mean programmers with fixed C-band costs would end up passing those along to remaining users, meaning rural consumers' prices would skyrocket or programmers will stop offering services altogether. Farquhar also said a market-by-market approach doesn't seem viable.
The BAC proposal might lead to too much traffic in the band, and there need to be more technical studies about how such an approach might work, said Farquhar. She also said it's not clear how point-to-multipoint system operations might adjust to the constant channel changing of satellite operators. Lieberman said there also are questions about how point-to-multipoint operations would be able to respond when a programming vendor, for example, changes from one satellite operator to another, or makes a programming lineup change.
Relocation costs might run in the hundreds of millions of dollars or "maybe more," Farquhar said. She said along with the 100 usable MHz, the satellite band-clearing plan would also need a guard band of perhaps 50 MHz, though the amount isn't clear. That leaves 350 MHz of space for existing services, thus necessitating more satellite launches, she said.