RRC States In LTE

UE states and state transitions.

·       A UE is in RRC_CONNECTED when an RRC connection has been established.

·       If this is not the case, i.e. no RRC connection is established, the UE is in RRC_IDLE state.

       

·       RRC_IDLE:

o    A UE specific DRX may be configured by upper layers.

o    UE controlled mobility;

o    The UE:

§  Monitors a Paging channel.

§  Information change, and for ETWS capable UEs.

§  Performs neighbouring cell measurements and cell (re-)selection;

§  Acquires system information.

·       RRC_CONNECTED:

o    Transfer of unicast data to/from UE.

o    At lower layers, the UE may be configured with a UE specific DRX.

o    Network controlled mobility.

o    The UE:

§  Monitors a Paging channel and/ or System Information Block Type 1 contents to detect system information change, and for ETWS capable UEs, ETWS notification;

§  Monitors control channels associated with the shared data channel to determine if data is scheduled for it;

§  Provides channel quality and feedback information;

§  Performs neighbouring cell measurements and measurement reporting;

§  Acquires system information.

·       The following figure not only provides an overview of the RRC states in E-UTRA, but also illustrates the mobility support between E-UTRAN, UTRAN and GERAN.



RRC States In LTE