Two weeks ago AT&T and Verizon reluctantly accepted to delay the launch of 5G on newly acquired C-band spectrum licenses by one month, until January 5, in response to the Federal Aviation Administration’s claim that the new service could interfere with the radio altimeters in use in airplanes.
Mobile operators are not the only ones frustrated by the delay. Telecommunications industry watchers point out that the Federal Communications Commission only approved the use of 3.7 GHz to 3.98 GHz C-band spectrum after analyzing claims of industry interference aviation and found no evidence to support these allegations. The FCC has also required a 220 MHz guardband that will remain unused to protect altimeters from interference. This guard band is more than twice as large as the 100 MHz buffer initially suggested by Boeing, the FCC said.
In addition, this spectrum is already said to be in use for 5G in nearly 40 countries without evidence of the problems reported by US aviation officials. “Tick, tick, tick … US wireless leadership and national security await ‘resolution’ of unfounded concerns by FAA,” former FCC Commissioner Mike O’Rielly tweeted yesterday.
Verizon and AT&T topped the auction
Verizon and AT&T topped the C-Band auctions when results were announced in February 2021, with winning bids from Verizon totaling $ 45.45 billion and AT&T totaling $ 23.41 billion. T-Mobile spent $ 9.34 billion on C-band spectrum, but primarily uses 2.5 GHz frequencies for its mid-range 5G deployment. The FCC issued the C band licenses in July 2021.
Verizon and AT&T have big plans for the C-band. They expect the 3.7-3.98 GHz spectrum to boost 5G networks with faster speeds than those provided on the below 1 GHz spectrum and Wider coverage areas than possible with millimeter wave spectrum, which does not work well with obstacles or long distances.
The radio altimeters used to determine aircraft altitudes are based on a spectrum of 4.2 GHz to 4.4 GHz. The adjacent C band was previously allocated for satellite service before the FCC reallocated it to cellular use. The band technically extends from 3.7 to 4.2 GHz, but the FCC has limited cellular use to 3.98 GHz and below to create the 220 MHz guard band.
FAA criticized for “new heights of irresponsibility”
The FCC is the expert agency on spectrum interference, and some industry observers say other US agencies have a habit of claiming interference issues without solid evidence. The “Federal Government Processes for Addressing Spectrum Policy [are] seriously broken “, Harold Feld, longtime telecommunications lawyer and senior vice president of consumer advocacy group Public Knowledge, wrote in a lengthy blog post about the dispute last week. “Disgruntled federal agencies that dislike the outcome of an FCC proceeding are responding by undermining the FCC in the press and trying to wage proxy wars through allies in Congress. But the actions of the FAA here is taking that behavior to new heights of irresponsibility and danger. “
Feld – a frequent critic of the way telecommunications companies treat users – wrote that he sided with the wireless industry on this issue in part because “the FAA had a year to collect information about available altimeters and start collecting data on whether 5G would cause harmful interference to all models, and what interference mitigation might be needed to avoid any potential for harmful interference … The aviation industry (with the silent backing of the FAA) has basically gone all or nothing. FCC file Calls on the FCC to prevent the activation of 5G networks on any part of the C-band until the aviation industry is satisfied that there is no potential risk of harmful interference. “
In some of the countries already using C-band, “5G signals operate in a spectrum adjacent to aircraft equipment. US airlines enter and leave these countries every day,” wrote Meredith Attwell Baker, president and CEO of the industry group. CTIA wireless. today. “If interference were possible, we would have seen it long before now. Nonetheless, we have added a layer of protection in the United States, called a guard band, which is hundreds of times greater than the separation that exists between the sans. wire and other spectrum users. “
The FAA did not recognize any “proven” interference
The FAA released a November 2 bulletin which warned of “potential adverse effects on radio altimeters”, but this bulletin acknowledged that there had been no “proven reports of harmful interference”, even in countries that allow 5G transmissions over the 3.98 GHz limit set by the FCC.
“Many countries around the world are already deploying wireless networks in the bands 3,300-4,200 MHz; some countries have implemented temporary technical, regulatory and operational mitigation measures, including temporary proximity and power restrictions, on wireless broadband networks operating in bands ranging from 3700 to 4200 MHz “, the FAA wrote. “There have not yet been any proven reports of harmful interference from wireless broadband operations internationally, although this issue continues to be investigated.” The United States have deployed wireless broadband in the 3.65-3.7 GHz range since 2007, the FAA noted.
In his February 2020 decision to reallocate the C-band spectrum, the FCC said the aviation industry’s research was unrealistic and urged the industry to do more testing, saying “further analysis is warranted on reasons there may even be a potential for interference given that well-designed equipment should generally not receive significant interference (let alone harmful interference) under these circumstances. ”About 20 months later, in the bulletin released this month, the FAA recommended that “radio altimeter manufacturers, aircraft manufacturers and operators voluntarily provide federal authorities with specific information relating to the design and functionality of altimeters, details of the deployment and use of radio altimeters in airplanes., and that they test and evaluate their equipment in collaboration with federal authorities. “
The FAA’s new warning to the aviation industry also noted that the FCC first requested comment on the use of C-band for mobile broadband in 2017.
“The 5G C-band issue has been hanging around for YEARS … why are they only now looking for better standards for altimeters? »Spectrum technology and policy consultant Michel marcus, an engineer who spent more than two decades working for the FCC, wrote on Twitter yesterday. Marcus also pointed out a July 2012 Report by a White House advisory board which recommended “spectrum management methodologies that take into account both transmitter and receiver characteristics to allow flexible spectrum sharing” because “receiver characteristics limit more and more efficient and flexible use of spectrum ”. In other words: receivers must be sufficiently well designed to protect against interference from transmissions in other spectral bands.
The FAA told the FCC in December 2020 that he “expects[s] that the cost of replacing or modernizing radar altimeters will be substantial. “
- Airlines Warn 5G on C-Band May Cause Major Disruptions
- The best resistance bands for workouts
- FCC considers crackdown on bad wireless receivers after 5G/altimeter debacle
- Boeing, Airbus engage in 5G brawl, ask Biden administrator to delay deployment
- FAA urges airlines to replace altimeters that can’t filter out 5G signals