How Long Will It Take to Resolve the Issues Surrounding C-Band 5G

Just when we thought we had heard about the last delay with C-Band 5G, the FAA now says it could take another year before areas around airports will benefit from C-Band’s speed upgrades. 

The subject was a hot topic that was discussed at a hearing held Thursday by the House Transportation and Infrastructure Committee. During this hearing, lawmakers voiced frustration with the Federal Aviation Administration and the Federal Communications Commission, and asked why the standoff was not resolved earlier.

The aviation industry and FAA had warned that 5G interference could impact sensitive airplane electronics such as radio altimeters, which gauge the height of an aircraft above terrain immediately below it and are used in low visibility landings. Steve Dickson, the FAA Administrator, testified that federal agencies need to improve their coordination in such matters because there will be additional spectrum issues in the future.

“The process did not serve anyone well,” Dickson said. “It did not serve the aviation community well, certainly the FAA, and it also did not serve the telecommunications industry well. And we certainly need to do better as a country.”

“5G and aviation can safely coexist,” Dickson told the panel. He then took the next two hours to explain how much work it’s going to take before that safe coexistence can occur.

With regards to the steps taken by AT&T and Verizon thus far, Dickson said he’s satisfied this will help to avoid possible interference on their initial C-Band 5G service. The frequency in question ranges from 3.7 to 3.8GHz and radio altimeters – the devices that the service can interfere with – operate from 4.2 to 4.4GHz. 

AT&T and Verizon have already pushed back their C-Band launches twice and agreed not to deploy C-Band in buffer zones around airports created by the FAA. This began in December, but rollouts did not start until January 19th. 

Intensive testing has been performed by the FAA and they continue to do so. They have already cleared 20 altimeter models and certified 90 percent of the US commercial fleet as safe to operate in low-visibility conditions that would require relying on radio altimeters.

“All parties are working together very effectively at this point,” Dickson said, crediting wireless carriers for providing the government with more detailed information about cell-site location, power strength, and signal shape.

What about smaller aircrafts? Regional and business jets, helicopters and other “general aviation” aircraft with altimeters are still uncertified against C-Band interference.

Dickson noted that discussions with altimeter manufacturers are showing some promise. They’ve suggested some of those altimeters could be fixed with radio-frequency filters. Ultimately, the FAA needs to write altimeter performance standards for C-Band resistance, which he said will probably take a year before manufacturers can design new units.

With that being said, it means the originally planned 6 month delay is going to run much longer. The good news is that the testing everyone is doing is already helping the FAA to chip away at the buffer zones, making them just a little smaller as time goes on. 

Almost every member of Congress at the hearing had the same questions we’ve had – how could an interagency coordination process meant to avoid last-minute conflicts could have gone so wrong? 

Dickson’s response put partial blame on the wireless carriers, saying that they did not provide sufficiently detailed technical data until December. Some committee members, meanwhile, blamed extended leadership vacancies during most of the Trump administration at the Commerce Department’s National Telecommunications and Information Administration (NTIA), the agency that’s supposed to help coordinate these efforts. 

A failure to communicate indeed, which still continues it seems since the FCC, which ran the C-Band auction, did not participate in the hearing. 

Boeing and Airbus Urge Biden Administration to Delay C-Band Rollout

Boeing and Airbus, two of the largest commercial airplane manufacturers, have joined the conversation about possible interference to aircraft tools from 5G’s C-Band spectrum. Like the FAA, they’re urging the Biden Administration to delay the rollout of service next month. 

Statements from the manufacturing companies were sent in the form of a letter to the Transportation Secretary, Pete Buttigieg, to say the January 5 rollout could cause interference that could “adversely affect the ability of aircraft to safely operate.”

The CEOs presented the idea of a new proposal – limit the power of 5G transmissions near airports, and call on the Biden administration to work with the FCC to adopt such a plan. 

Indications were made that amongst the trouble caused by the pandemic, it is not worth the risk of deploying the service without restrictions. Such as the new rule the FAA announced earlier this month. It forbids pilots from using auto-landing and other certain flight systems at low altitudes where 5G wireless signals could interfere with onboard instruments that measure a plane’s distance to the ground. 

The rule was characterized as urgent, so the FAA bypassed the typical public feedback process in issuing the restrictions. It is that important, as it affects more than 6,800 US airplanes and dozens of aircraft manufacturers, and could lead to disruptions in some flight routes involving low-visibility conditions, which obviously poses potential risks. 

US Aviation Restrictions and 5G C-Band Interference

Concerns over the 5G C-Band (3.7-3.98 GHz) and aviation safety are still a hot topic. While there have been no reports of any issues, these concerns are quite valid. If you’re not already familiar with this story, the FAA alerts say that 5G can interfere with radar or radio altimeter signals. These tools measure the distance between the aircraft and the ground. Data from these devices are then fed to the cockpit safety system. This helps pilots gauge the air safety metrics and prevent mid-air collision, avoid crashes and ensure a safe landing.

In order to avert any potential disruption in essential safety sensors, the FAA issued flight restrictions that would prevent pilots from operating the automatic landing option and other cockpit systems during inclement weather conditions. These directives are primarily intended to make 5G expansion and aviation coexist without compromising passenger safety. However, some airline industry groups have voiced concern because this can impact flights when they need these tools and systems the most.

Along with the FCC, the FAA has been conducting safety studies to help move things forward, as the telecom industry continues to argue the concerns are invalid. Specifically in the spotlight, Verizon and AT&T have cited data from several countries where the C-Band has been safely coexisting with the aviation industry. Despite these arguments, the two telecom companies have voluntarily suspended the rollout of the C-Band until January 2022. The carriers have also agreed to minimize the power consumption of C-Band base stations around airports till July 6, 2022. In the meantime, they continue to work together to resolve the issue. 

Both Verizon and AT&T have a lot in stake with C-Band. The C-Band offers significant bandwidth with better propagation characteristics for optimum coverage in both rural and urban areas than mmWave, which has a short range and requires a high density of sites to achieve coverage. Consequently, it is deemed a prized asset for carriers like Verizon and AT&T that lack considerable mid-band spectrum holdings. Verizon was the largest bidder with $45.5 billion worth of bids in the FCC-led C-Band auction for mid-band airwaves that generated about $81.2 billion in gross proceeds, followed by AT&T at $23.4 billion. The auction offered 280 MHz of spectrum for potential 5G deployments over the next few years. While Verizon secured 3,511 of the 5,684 licenses up for grabs, AT&T claimed 1,621.

On the other side, leading U.S. House Democrats have urged the FCC to consider the gravity of the issue raised by the FAA. They’ve sought an immediate restraining order for the deployment of the C-Band for wireless use until a thorough risk assessment is conducted. Although the FCC did not comment, a coalition of industry trade groups has pointed out that further delay in the rollout of 5G technology would likely hamper the country’s economic growth.

AT&T and Verizon agree to Limit 5G C-Band Spectrum for 6 Months due to FAA Concerns

For the past few weeks, we’ve reported about the delay on Verizon and AT&T’s rollout of 5G service on the C-band spectrum. Originally planned for only 1 month, the delay is due to concerns about interference with aircraft sensors

While the FAA still investigates this, there have yet to be any reports of incidents with actual interference. This is known because this particular section of frequency spectrum is already used in almost 40 other countries. All of which have never reported issues. 

The FCC has been involved and even approved use of the C-Band spectrum from 3.7 to 3.98 GHz. This came only after analyzing the aviation industry’s interference claims and finding no evidence to support the claims. The FCC also required a 220 MHz guard band that will remain unused to protect altimeters from interference. That guard band is more than twice as big as the 100 MHz buffer initially suggested by Boeing, the FCC has said.

As detailed in a proposal posted on Wednesday, the carriers (AT&T and Verizon), have agreed  to lower the signals’ cell-tower power levels nationwide and impose stricter power caps near airports and helipads, according to a copy reviewed by The Wall Street Journal. This implementation will last for at least 6 months while the FAA continues to monitor the situation.

“While we remain confident that 5G poses no risk to air safety, we are also sensitive to the Federal Aviation Administration’s desire for additional analysis of this issue,” the companies said in the letter to FCC Chairwoman Jessica Rosenworcel. Wireless industry officials have held frequent talks with FCC and FAA experts to discuss the interference claims and potential fixes, according to people familiar with the matter.

The FAA welcomed the proposal, but has not yet indicated whether it will agree to it.

The paper also notes that 5G users shouldn’t be significantly affected as carriers already use directional antennas near airports to limit the power of the signals reaching aircraft, and within terminal buildings most people use WiFi.