Jun 242009
*Idle mode: CN-level
UE is identified with TMSI (temporary mobile subscriber identity)
*RRC connected mode: UTRAN-level
UE is identified with C-RNTI and U-RNTI
Cell_FACH and Cell_PCH: every cell change needs to be reported via cell update
URA_PCH: every URA change needs to be reported via cell update
(less signal overhead from UE perspective, but more paging messages need to be injected into multiple cells)
