This TS specifies the Access Stratum (AS) part of the Idle Mode procedures applicable to a UE. The nonaccess stratum (NAS) part of Idle mode procedures and processes is specified in TS 23.122
This TS specifies the model for the functional division between the NAS and AS in a UE.
This TS applies to all UEs that support at least E-UTRA, including multi-RAT UEs as described in 3GPP specifications, in the following cases:
When the UE is camped on an E-UTRA cell;
When the UE is searching for a cell to camp on.
Note: When the UE is camped on or searching for a cell to camp on belonging to other RATs, the UE behaviour is described in the specifications of the other RAT.