Thursday, 29 October 2015

LTE UE Connection Management Overview

1、LTE Attach Procedure

1. UE sends Attach request. NodeB selects MME.
2. Request IMSI
3. Activate integrity protection and NAS ciphering
4. Location update from MME to HSS
5. Entry for the new bearer
6.-8. New bearer creation
9. Attach complete


 2、LTE Radio Resource Control (RRC) States
RRC Connected State
UE location is known in MME with an accuracy of a cell ID
The mobility of UE is handled by the handover procedure
The UE performs the tracking area update procedure
A signalling connection exists between UE and MME
RRC Idle state
No signalling connection between UE and network exists
No UE context exists in EUTRAN
UE performs cell reselections
Paging needed when the there is data in downlink direction
   • RACH procedure used on establish RRC connection

   3、LTE UE RRC Connection Maintenance
UE’s RRC connection can be maintained even if UE is inactive
RRC connection may be released due to the following reasons

4、LTE Tracking Area
Tracking area (TA) is similar to Location/routing area in 2G/3G
Tracking Area Identity = MCC (Mobile Country Code), MNC (Mobile Network Code) and TAC (Tracking Area Code)
When UE is in Idle, MME knows UE location with Tracking Area accuracy

Budi Prasetyo

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