LIFE OF A LTE MOBILE

An UE goes through a number of steps before requesting for a service, and setting up and managing the service itself requires some additional steps.

When a UE powers up in an E-UTRAN, it undergoes the following steps:

1.     Ti scans for eNB to acquire the network, synchronize with the network, and listen for system information over the broadcast channels.

2.     Initiate a signalling connection to communicate with the eNB.

3.     Request an attach to the core network to register and receive service.

4.     Carries the authentication with the core network and exchange information about security algorithms and keys.

5.     Initiates a default EPS bearer with the default PDN (Packet Data Network) and obtain an IP address to provide always-on experience to the user.

6.     Frame default EPS bearer with each of the other PDNs if needed. Frame–up one or more dedicated EPS bearer if the QoS of services cannot be fulfilled by the default EPS bearer.

7.     After obtaining DL and UL resources from the eNB, it exchange packets with the network.

8.     Execute the handover instructions received from the eNB when the RF environment changes to maintain the best possible radio link.

9.     Begin the idle mode when the radio resources are no longer required due to lack of data activity.

10. Accomplish detach operation in case of power – off.

In conditions of detach, the UE loses all EPS bearers and the IP address. The EPS no longer knows the location of the UE.