Wireless Technology Terms, Glossary and Dictionary
TMSI: Temporary Mobile Subscriber Identity
Temporary Mobile Subscriber Identity (TMSI) is the identity that is most commonly sent between the mobile and the network. It is a randomly allocated number that is given to the mobile at the moment it is switched on. The number is local to a location area, and so it has to be updated, each time the mobile moves to a new geographical area. The network can also change the TMSI of the mobile at any time. And it normally does so, in order to avoid the subscriber from being identified, and tracked by eavesdroppers on the radio interface.