LTE RRC connection setup

LTE RRC connection setup

Establishing an RRC connection in LTE typically involves the following steps:

1. UE initiates a session to the eNodeB using a random RA-RNTI.
2. eNodeB assigns a C-RNTI and sends timing adjustment to the UE.
3. UE adjusts the timing and sends an RRC Connection Request via the UL-SCH channel.
4. The eNodeB sends the RRC Connection Setup to the UE on the DL-SCH channel. This message sets up the SRB. DRB may also be established at this point.
5. Finally, the UE acknowledges the message with RRC Connection Complete message.

The messages in the RRC Connection Setup are described in the following presentation.

LTE RRC Connection Setup Messaging