Canada Limits 5G To Protect Air Travel (forbes.com)

ISED’s concerns about the potential interference with altimeters by 5G operations in the 3.45 – 3.65 GHz band in Canada emerge the same week that the FCC completed the auction of licenses in the 3.45 – 3.55 GHz band in the United States for more than $20 billion. The FCC order authorizing the auction has no mention of altimeters, much less potential interference.

The Canadian restrictions include “exclusion zones” around 26 airports where outdoor 5G base stations would not be permitted to operate—but indoor 5G operations would be allowed. ISED has also established “protection zones” where 5G operations would be allowed, with restricted power. Furthermore, ISED requires, until it decides otherwise, that the 5G antennas tilt down, rather than horizontally or upward, so as not to interfere with the radio altimeters. These restrictions would be in effect until both domestic and international studies have come to a definite conclusion about the scope of the problem.

Similar discussion is going on in the United States, following the planned rollout of 5G in the 3.7 – 4.2 GHz section of spectrum known as the C-Band, originally due on December 5, now postponed until January 2022. Last year the Federal Communications Commission auctioned the rights to licenses in the C-Band to, among others, Verizon, AT&T, and T-Mobile to use for 5G services. These companies paid over $80 billion for spectrum that would help provide consumers with faster mobile Internet services. The C-Band is much closer to the spectrum used for altimeters, and consequently the C-Band would reasonably pose greater interference concerns than the 3.45 – 3.55 GHz band. The FCC order authorizing the C-Band auction mentions altimeters but makes no specific accommodation for them.