| 摘要 |
<p>A subscriber identification module (SIM) for storing user identities and other user-specific information and thereby enables access to the service of the radio system. One of the user identities is Temporary Mobile Subscriber Identity (TMSI) used for user anonymity purposes by utilizing it as an alias for the actual user identity in order to avoid sending the actual user identity in clear on the radio path. A part of TMSI is a random number which cannot be used to identify the user/terminal without mapping information to the actual user identity, which is found in the telecommunications network entity that allocated the random number. The present invention allows an SIM roaming from one radio system to another by utilizing predetermined bits of TMSI are used to differentiate between different TMSI's of different systems indicating in a uniform manner in all mobile radio systems the mobile radio system which has allocated the TMSI.</p> |
