Boeing and Airbus have written a joint letter to US Transportation Secretary Pete Buttigieg asking that Verizon and AT&T’s rollout of C-band 5G be delayed. At the heart of the issue is concern over interference with aircraft altimeters.
Verizon and AT&T were the largest bidders for C-band spectrum, in the mid-band range, at a recent FCC auction. In fact, under its legal name Celco Partnership, Verizon spent $45,454,843,197 while AT&T spent $23,406,860,839 (via the FCC).
Collectively, the two companies spent more than $68 billion on C-band spectrum because that spectrum is in the 3.7 to 3.98 GHz range, which is considered ideal for 5G. Low-band spectrum, such as what Verizon, AT&T, and T-Mobile use for their nationwide 5G networks, offers a superior range, but its speed is not much faster than 4G LTE. The fastest flavor of 5G — mmWave in the 6 GHz and higher range — offers multi-gigabit performance, but has very limited range and building penetration.
In contrast, C-band falls squarely in the middle, providing excellent speed combined with decent range and building penetration.
Despite the promise of C-band spectrum for 5G applications, airlines sounded the alarm over concerns of interference with altimeters, which operate in the 4.2 to 4.4 GHz range.
Because altimeters and C-band spectrum are relatively close, airlines and the FAA are concerned that 5G signals could interfere with altimeters and impact their accuracy. The concerns led both Verizon and AT&T to initially delay their rollout, and then agree to limit the power output of their spectrum deployment, especially in the vicinity of airports and helipads. (via The Hill).
Despite Verizon and AT&T’s concessions, the FAA issued new guidelines limiting the use of altimeters in low visibility conditions when 5G might interfere.
These concerns are what prompted Boeing and Airbus executives to ask for a delay in Verizon and AT&T’s C-band rollout, saying that “5G interference could adversely affect the ability of aircraft to safely operate.” According to Reuters, the letter goes on to say that continuing with the rollout could have “an enormous negative impact on the aviation industry”
Obviously, with more than $68 billion invested in the C-band spectrum, Verizon and AT&T are not thrilled with the situation, and both companies are downplaying the potential issues. Only time will tell whether the danger is real, or whether those concerns are overblown.
