A radio access technology (RAT) is the underlying physical connection method for a radio communication network. Many modern mobile phones support several RATs in one device such as Bluetooth, Wi-Fi, and GSM, UMTS, LTE or 5G NR.
The term RAT was traditionally used in mobile communication network interoperability.[1] More recently, the term RAT is used in discussions of heterogeneous wireless networks.[2] The term is used when a user device selects between the type of RAT being used to connect to the Internet. This is often performed similar to access point selection in IEEE 802.11 (Wi-Fi) based networks.[3]