UMTS address can be classified
1. CN address
- IMSI
-TMSI
-P-TMSI
2. UTRAN address
- S-RNTI
- U-RNTI
- C-RNTI
3. UE ID dedicated channels
P-TMSI (packet TMSI) is similar to TMSI except that it is for PS domain.
P-TMSI is 32 bit number and used as a temporary id within the PS domain.
TMSI (temporary IMSI) together with LAI uniquely identifies the subscriber.
TMSI is assigned by the network and is 32 bits.
It is used to mask the identity of the subscriber and hide the subscriber’s true identity (IMSI).
*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 [...]
