After a bruising fight between carriers and the aviation industry over 5G, an aviation coalition has laid the groundwork for the next round.

Verizon and AT&T spent billions to purchase C-band spectrum at Federal Communications Commission (FCC) auctions. C-band is considered among the best spectrum for 5G, providing a good balance of speed, range, and building penetration.

The Federal Aviation Administration and the airline industry objected to Verizon and AT&T deploying C-band around airports, sparking a major debate about the safety of 5G and the airlines. The concern revolved around potential interference with airplane altimeters, which operate on spectrum very close to C-band.

The parties eventually agreed to limit C-band deployment around airports until July 2023, but aviation advocates want to make that ban permanent, especially for C-band in the 4,200-4,400MHz range. The advocates also want 5G transmitters restricted from pointing 90 degrees above the horizon.

The aviation coalition outlined their wishes in a letter to the FCC:

These concepts, such as preventing antennas pointing 90 degrees above the horizon and maintaining the wireless spurious emissions in the 4200-4400 MHz band consistent with current mitigations, would appear to not compromise wireless operators’ actual use cases while further assuring aviation safety and providing a workable RF environment against which future radio altimeters can be designed and built.

Only time will tell if the aviation advocates will prevail, although Verizon and AT&T will likely strongly oppose any extension of the C-band limits. Whatever the outcome, all parties no doubt want to avoid the fallout they experienced from Round One.