The FCC has designated this band for shared use according to a 3-tier spectrum architecture:
» Tier 1 is occupied by Incumbents, specifically the US Navy, with rare activity near the coastal regions in the
3550 -3700 MHz band and Fixed Satellite Earth Stations, with multiple fixed Locations (Receive only) in the 3600
– 3700 MHz band. Military, DoD, Satellite, Utility and other governing bodies will retain first priority, in
particular in certain coastal areas, in order to protect their operations from harmful interference.
» Tier 2 is designated as Priority Access License (PAL). The licenses for this service were auctioned in mid-2020
(Band 3550 – 3650 MHz). Each PAL will be defined for a period of time and specific locations based on single
census tracts.
» Tier 3 is the General Authorized Access (GAA) with administration by Spectrum Access System (SAS), who
centrally coordinates access the shared spectrum, enforcing priorities and monitoring the incumbent operation
for the RF environment. This level will allow the widest possible group of potential users. GAA users are
permitted to use, through dynamic allocation, any portion of the 3550-3700 MHz band not assigned to a higher
tier user. They will also be able to operate in unused portions of the Priority Access channels.
