Based on the search results, RAT stands for Radio Access Technology, which 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 is used when a user device selects between the type of RAT being used to connect to the Internet. Serving Cell Info is an option under RAT that provides information about the signal strength of the cell tower that the device is currently connected to. The RSRP value represents the signal strength.