The 3 GHz band is one of the most desirable bands for wide-area 5G deployments due to the favorable propagation characteristics and availability of 100 MHz wide channels. Most countries have deployed 5G in various subsets of 3GPP defined bands n77 (3.3–4.2 GHz) and n78 (3.3–3.8 GHz), depending on local usage. For example, in the U.S. 3.45–3.55 GHz and 3.7–3.98 GHz have been allocated for high-power exclusive use, while 3.55–3.7 GHz, the CBRS band, has been allocated for shared access using low and medium power since the U.S. also deploys Navy radars in the band [1]. Many European countries have allocated parts of the 3.4–3.8 GHz band for exclusive, high-power use, while evaluating 3.8–4.2 GHz for local licensing [2]. Given the limited available bandwidth remaining in the 3 GHz band, there is increasing focus on methods to either share the band or reallocate to new services. In this column we will discuss a recent Notice of Inquiry (NOI) from the U.S. Federal Communications Commission (FCC) requesting comments specifically on the 3.98–4.2 GHz band [3].
