Wireless Oom

The IMSI identifies the subscriber (USIM) within the network.
This is the permanent address stored in HLR.
IMSI =MCC (mobile country code) + MNC (mobile network code) + MSIN (mobile subscriber identification number)
15 bits
MCC + MNC is PLMN id.

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