With the announcement of Google Pixel 3 and Pixel 3XL, it was revealed all the carrier support the devices would support. However, nowhere in the launch documents of FCC, it was mentioned that the devices will support LTE Band 48. An FCC addendum that was filed in November 2018 was made public today, the addendum shows that the PIxel 3 and Pixel 3XL will support LTE Band 48 via a software update.
It is specifically mentioned in the FCC addendum that the update will be available for G013A, which is the model number for the international version of Pixel 3. The G013A is the version that is sold everywhere outside of Japan, so this would include the majority of Pixel devices sold in the world.
Japan often gets different hardware variant of the same phone sold globally because they need to have an Osaifu-Keitai(Mobile Wallet) compatible secure element in the device. This enables the device to read and write to FeliCa cards which is an RFID smart card system primarily used in electronic money cards.
The LTE BAnd 48 is not well known, although it was also known as the CBRS Band when Verizon had partnered up with Ericsson, Qualcomm, and Federated Wireless to claim the first use of CBRS Band 48 Spectrum. LTE Band 48 is made up of 150 MHz of 2.2 GHz shared spectrum which has been historically used by the U.S government for radar systems. The FCC intends to commercialize the LTE Band for network providers like Verizon, AT&T, and Sprint. With this Band in use, phones could stay connected even in areas that have low network reception, and to pump out LTE-advanced with career aggregation, or for 5G.
Federated Wireless has said that they are providing its Spectrum Access System “to dynamically prioritize traffic” within FCC’s spectrum-sharing network.
Carriers in the United States have gone on record saying they would require 3.5 MHz spectrum as a core band to deploy 5G around the world.