5G: ‘The dog that did not bark’

5G is the fifth generation of cellular networks, advertised as 100 times faster than 4G. Other 5G features include ultra low latency— meaning it is optimized to process a high volume of data packets with no delays—high reliability, massive network capacity, increased availability, and uniform user experience. With its greater bandwidth, 5G is seen facilitating better services such as e-health, connected vehicles and traffic systems, and advanced mobile cloud gaming.

From Bloomberg: “A trade association representing major US airlines asked Transportation Secretary Pete Buttigieg and the nation’s top communications and aviation regulators to prevent wireless carriers from implementing 5G services close to airports. Airlines for America warned in a letter Monday that the traveling and shipping public could see “catastrophic disruptions” if the new C-band frequencies were put into service within 2 miles of where aircraft fly. The association said it was willing to work with the government and carriers to find a mutually agreeable solution.”

In 2021, the US government auctioned mid-range 5G bandwidth to mobile phone companies in the 3.7-3.98 GHZ range on the spectrum, known as Cband, for about $80 billion. Wireless carriers including AT&T Inc. and Verizon Communications Inc. reached an agreement with federal regulators earlier this month to launch the new service on January 19. But the airlines are worried the signals could interfere with instruments that measure an aircraft’s altitude.

The new high-speed wireless service uses a segment of the radio spectrum that is close to that used by altimeters, which are devices that measure the height of the plane above the ground. Altimeters are used to help pilots land when visibility is poor, and they link to other systems on the aircraft.

AT&T and Verizon dismissed the concerns saying their equipment will not interfere with aircraft electronics, but they offered to reduce the power of their 5G networks near airports, as France has done. “The laws of physics are the same in the United States and France,” said AT&T CEO John Stankey and Verizon CEO Hans Vestberg in a letter to Buttigieg and FAA Administrator Stephen Dickson, whose agency is responsible for aviation safety. “If US airlines are permitted to operate flights every day in France, then the same operating conditions should allow them to do so in the United States.”

The US wireless industry trade group CTIA said in a filing with the Federal Communications Commission that “wireless carriers in nearly 40 countries throughout Europe and Asia now use the C-band for 5G, with no reported effects on altimeters that operate in the same internationally designated 4.24.4 GHZ band.” CTIA added: “Each day US aircraft, carrying thousands of US citizens, land in these countries without incident and with no expression of concern by the FAA or foreign aviation regulators. This is the classic dog that did not bark. The laws of physics are no different in the United States than in Europe or Asia.”

In South Korea, where the 5G mobile communication frequencies are in the 3.42-3.7GHZ bands, there has been no report of interference with radio wave since the commercialization of 5G in 2019. Currently, its 5G mobile communication wireless stations are in operation near airports, but there have been no reports of “catastrophic disruptions”.

“I am shocked to see the reaction of US airlines at the last moment,” said Rohan Dhamija, managing partner of a global telecoms, media and technology management consulting firm. The 3.5 GHZ C-band “was allocated after a lot of testing, and after adequately ensuring there’s no interference with anything else.”

Randall Berry, a professor of electrical and computer engineering at Northwestern University, likened the interference issue to two stations that overlap on the radio dial. The Fcc-determined separation “may be enough for some [altimeters] but not for others,” he said. One solution that Berry proposed is to provide all altimeters with good filters against interference. Although there could be a fight over who pays for that work, both the telecoms industry and the airline industry are too profitable for a solution not to be found. Pundits said it is likely that existing altimeters will be rated as safe eventually, or the airlines will design new ones that work against 5G interference.