LTE Access and Registration Procedures
This LTE access and registration procedures hub helps you quickly find the main call flows used when a UE enters LTE service, starts EPS registration, and moves toward normal packet connectivity.
Quick Links
What This Covers
This section includes the main LTE procedures used when the UE enters the network, starts EPS registration, and moves toward normal packet service.
The common nodes in these flows are the UE, eNB, MME, SGW, PGW, and HSS.
These procedures are often the starting point for later service behavior, so issues here can affect attach, bearer setup, mobility updates, and idle-to-connected recovery.
Initial Access
Procedures that bring the UE into LTE service and start EPS registration.
- LTE Attach Procedure — UE enters EPS service and establishes initial registration and bearer context.
- LTE Combined EPS / IMSI Attach Procedure — Combined attach for EPS and legacy mobility domains.
- LTE Emergency Attach Procedure — Emergency-oriented LTE access flow.
Service Restoration
Procedures that restore service after idle mode or resume control-plane activity.
- LTE Service Request Procedure — Restores UE service and user-plane availability after idle state.
- LTE Extended Service Request Procedure — Used for service recovery in cases such as CS fallback-related continuation.
Mobility Registration Update
Procedures that update UE registration and tracking state while remaining in LTE service.
- LTE Tracking Area Update Procedure — Updates the UE's tracking area registration and mobility context.
- LTE Periodic Tracking Area Update — Periodic registration refresh driven by network policy and timers.
Exit Procedures
Procedures that remove or end LTE registration and service state.
- LTE Detach Procedure — Releases EPS registration and ends LTE service context.