LTE Tracking Area Update signaling flow describes how mobiles keep the network updated about their location.
A Tracking Area Update takes place if:
- UE detects it has entered a new Tracking Area that is not in the list of TAIs that the UE registered with the network;
- the periodic Tracking Area update timer has expired;
- UE was in UTRAN PMM_Connected state (e.g. URA_PCH) when it reselects to E UTRAN;
- UE was in GPRS READY state when it reselects to E UTRAN;
- the TIN indicates “P-TMSI” when the UE reselects to E-UTRAN (e.g. due to bearer configuration modifications performed on
- the RRC connection was released with release cause “load re-balancing TAU required”;
- a change of the UE Core Network Capability and/or UE Specific DRX Parameters information of the UE.