temporary mobile subscriber identity (mobile communications) (TMSI)

The Temporary Mobile Subscriber Identity (TMSI) is a subscriber identifier temporarily assigned to the mobile subscriber.

There is a direct link between the TMSI number temporarily assigned by the Visitor Location Register( VLR) and the actual subscriber number, which is known only to the network operator. The network operator also defines the structure of the TMSI number.

Each time the radio cell is changed, the radio network assigns the subscriber a new temporary subscriber number. The reason for this measure is data protection and the associated difficulty in creating movement profiles of a subscriber.