Registration types: initial, mobility, periodic, emergency

Four Types of 5G Registration

Before a UE can use any 5G service, it must register with the network. 5G defines four registration types triggered by different events. Initial Registration occurs when the UE powers on for the first time, inserts a new USIM, or enters a new PLMN. It requires full authentication and key agreement. Mobility Registration is the equivalent of a Tracking Area Update — triggered when the UE moves into a new tracking area not in its current TAI list while in idle or inactive mode.