Wireless Oom

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).

LAI: Location Area Identifier: PLMN id + LAC(location area code) = 24+16=40 bits
RAI: Routing Area Identifier:LAI + RAC (routing area code) =40+8 = 48 bits
URA: UTRAN Routing Area: URA = 16 bits
UTRAN cell id: UC id= RNC id + cell id = 12+16 = 28 bits