More C-band uncertainties appear in 5G radar


After months of controversy over 5G C-band compatibility with commercial aviation, wireless carriers, aircraft operators and government regulators seem significantly closer to landing this plane. But disagreements remain on some critical waypoints, with one element essentially resolved: future spectrum allocation rounds cannot go like this.

“It’s very expensive to try to solve this problem after you’ve already deployed the network,” summed up Harold Feld, senior vice president of the nonprofit Public Knowledge.

Some airline industry executives are concerned that 5G operations in the C-band spectrum could interfere with aircraft radio altimeters – gadgets that can be essential for landing in low-visibility conditions. Those concerns turned into a remarkable few weeks of very public, high-stakes negotiations that ultimately resulted in AT&T and Verizon agreeing to delay their 5G launches near certain airports.

For a few days, however, the situation seems to have calmed down. For example, the FAA’s list of aircraft types with approved altimeters for operations around these airports grew rapidly – 45% of the US commercial fleet on January 16, 62% on January 19, 78% on January 20 and 90% on January 25. The Federal Aviation Administration (FAA) says this fraction covers all Airbuses and Boeings but leaves Embraer 145s and a few other older regional jets uncertified. And, according to ReutersVerizon is preparing to activate another 2,000 cell towers with 5G operating in its C-band spectrum, in addition to the 5,100 towers already running the technology.

Questions remain about the Embraer 145 and 5G in the C-band spectrum.
(Source: Embraer)

Interestingly, the FAA has yet to confirm any reports of 5G C-band interference, according to a statement provided to Light Reading on Tuesday: “We are using our established safety reporting systems to review a handful of reports of possible interference 5G. So far, none of these reports have been validated.”

And after

All of this leaves three unresolved areas of uncertainty.

Perhaps the trickiest part is how to replace the fraction of radio altimeters in use that cannot be certified as sufficiently resistant to interference – an expense that incumbents would rather not pay.

“They don’t want to spend money on equipment that works perfectly right now,” said Jeffrey Westling, director of technology and innovation policy at American Action Forum, another nonprofit. technology policy in Washington. “It’s really going to be who has to pay for this.”

Feld of Public Knowledge mentioned a few possibilities: Congress could add funding for these upgrades to a future budget bill, the government could tell aircraft operators to bear the cost, or some kind of agreement could be reached for mobile operators to cover these. material expenses.

The latest, he said, would receive a hostile reception among companies that have spent $81 billion and change the C-band auction that ended in January 2021.

“To be told that there are now a few billion more that they have to recover is not going to go very well,” Feld commented. “If the wireless industry is paying, they’ll want to make sure the problem is gone forever.”

Then there are the long-term outlines of restricted or excluded areas around airports after AT&T and Verizon ended six-month self-imposed restrictions on C-band deployment near airports.

“What will it take for the FAA to be satisfied that the risks of interference have been sufficiently mitigated to allow 5G networks to operate at full strength with full coverage near airports?” Tammy Parker, a senior analyst at research and consulting firm GlobalData, asked in an email Friday. “The FAA hasn’t publicly set the goalposts, so it appears no one outside of the FAA understands exactly what will be required for the FAA to approve the end of the 5G exclusion zones.”

On Tuesday, a statement from the FAA provided a bit more clarity, suggesting that while the agency might be able to further reduce these exclusion zones, zeroing them would have to wait for altimeter upgrades: “L “The agreement with telecommunications companies we announced on Friday establishes a reliable and predictable process for the safe integration of 5G as the aviation industry strives to develop radio altimeters immune to 5G interference.”

The FAA on Friday announced an agreement with AT&T and Verizon that allowed the agency to reduce its current 5G exclusion zones.

However, a security expert has suggested the FAA stick to a hardline approach to these restrictions.

“Do it like regulators in Canada and the EU have done,” urged Robert Mann, president of aviation industry consulting firm RW Mann. & Co. For example, the Government of Canada has drawn exclusion and protection zones around many airports. Exclusion zones extend 2.1 kilometers beyond the end of a runway and 910 meters on either side and prohibit C-band sites, while protection zones, each 1 km in length wide, extend an additional 6.1 km beyond the exclusion zones and subject C-band sites to power limits.

Mann, however, added that he would prefer to see exclusion zones extending 4 nautical miles – 4.6 miles or 7.4 kilometers – from the ends of runways to further reduce the risk of interference.

This kind of insistence on a margin of error even with the most pessimistic assumptions can grill on types of telecommunicationsbut Mann placed it in an existential context for commercial aviation: “All of industry’s demand for public use depends on a safety assumption.

More potential turbulence ahead

The failure of inter-agency collaboration that has contributed to this situation is perhaps the only thing that all parties can agree on to remedy the situation.

Feld defended the FCC’s priorities, saying its engineers “take their life and safety responsibilities very, very seriously,” and instead pointed to too many recent vacancies in the leadership of the National Telecommunications Administration. and Information (NTIA) of the Department of Commerce. This left the NTIA misplaced for the FCC and FAA to talk to each other soon after. the FCC vote in 2018 to start the transition to C-band. As he said, “Imagine if you had a diplomatic conference and the translators didn’t show up.”

Mann agreed with that, calling the NTIA under the Trump administration “asleep at the switch.”

The parts of commercial aviation outside of the scheduled airlines haven’t been the subject of much discussion yet – as Westling put it, “they don’t get as much public attention as canceled flights. ” – but they will also have to be covered in the long term. eventual resolution of the problem.

Helicopters represent the trickiest part of this problem, as they operate from helipads that can be scattered around cities and often fly at much lower altitudes. These factors may mean that altimeter certification is the only way forward for them. But while the FAA continues to test individual altimeter models for helicopters as well as fixed-wing aircraft, it does not list which ones it has authorized or offer a percentage estimate like what she supplied for airliners.

In the meantime, FAA guidance says that medical evacuation helicopter pilots can “continue to use safety-enhancing night vision goggles” when operating outside of visual flight conditions.

And as complicated as current C-band concerns may be, the situation could get even worse in 2023. That’s when the B and C Block licenses of the C band will become available for commercial use – they are even closer to radio altimeters than the current block A licenses under discussion.

But the recent months of drama seem to have captured the attention of all interested parties — including those at the highest levels of the federal government.

“I’m optimistic that the White House has repeatedly made it clear that this issue needs to be addressed,” Feld said. “And the solution is not C-band 5G.”

— Rob Pegoraro, special for Light Reading. follow him @robpegoraro.


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