Finding copied sim cards

• US 6,341,220 B1
• Filed: 10/30/1998
• Issued: 01/22/2002
• Est. Priority Date: 03/10/1997
• Status: Expired due to Term

• Current Assignee: WSOU Investments, LLC (WSOU Holdings, LLC)
• Original Assignee: Nokia Telecommunications Oy (Nokia Corporation)
• Inventors: Hurme, Jaana
• Primary Examiner(s): Kincaid, Lester G.
• Application Number:
  US09/180,034
• Time in Patent Office: 1,180 Days
• Field of Search: 455/410, 455/411, 455/432, 455/433, 455/456, 455/518, 455/519, 455/435, 455/422, 455/67.1, 380/247, 380/248, 380/250, 380/258, 380/270, 379/189
• US Class Current: 455/410
• CPC Class Codes: H04L 63/0853 using an additional device, e.g. smartcard, SIM or a different communication terminal cryptographic mechanisms or cryptographic arrangements for entity authentication involving additional secure or trusted devices H04L9/3234
• CPC Class Codes: H04L 63/1408 by monitoring network traffic monitoring network traffic per se H04L43/00
• CPC Class Codes: H04L 63/1441 Countermeasures against malicious traffic countermeasures against attacks on cryptographic mechanisms H04L9/002
• CPC Class Codes: H04W 12/06 Authentication
• CPC Class Codes: H04W 12/126 Anti-theft arrangements, e.g. protection against subscriber identity module [SIM] cloning
• CPC Class Codes: H04W 12/72 Subscriber identity

Abstract

A method and apparatus implementing the method for detecting copying of an international mobile subscriber identity in a mobile communication network in which the location of mobile stations is updated in at least one register of the network. According to the method, the number of at least one type of location updatings (advantageously inter-MSC) is monitored within a predetermined monitoring period (e.g. 24 hours). This number is compared to a predetermined threshold value, and if the number of location updatings exceeds the predetermined threshold value, a signal indicative of the exceeding will be generated.

Claims

1. A method for detecting copying of a subscriber identity (IMSI) in a mobile communication network in which the location of mobile stations (MS) is updated in at least one register (HLR, VLR) of the network, comprising:

monitoring, for at least some of the mobile stations (MS), the number (N) of location updatings of at least one type during a predetermined monitoring period;

comparing said number of location updatings to a predetermined threshold value (N_MAX);

maintaining a group of special subscribers; and

in response to said number (N) of location updatings exceeding the predetermined threshold value (N_MAX), generating a signal indicative of exceeding said predetermined threshold value (N_MAX) only when a subscriber is not one of said special subscribers.

2. A method as claimed in claim 1, wherein the type of location updatings being monitored comprises an inter-MSC location updating.

3. A method as claimed in claim 2, wherein the type of location updatings being monitored comprises a location updating between such base stations (BTS) that are at least some tens of kilometers apart.

4. A method as claimed in claim 3, comprising:

classifying the subscribers into at least two categories; and

setting a different threshold value for each category.

5. A method as claimed in claim 3, wherein said threshold value (N_MAX) is subscriber-specific and depends on the previous frequency of location updatings by the same subscriber.

6. A method as claimed in claim 2, comprising:

classifying the subscribers into at least two categories; and

setting a different threshold value for each category.

7. A method as claimed in claim 2, wherein said threshold value (N_MAX) is subscriber-specific and depends on the previous frequency of location updatings by the same subscriber.

8. A method as claimed in claim 1, wherein the type of location updatings being monitored comprises a location updating between base stations (BTS) that are at least some tens of kilometers apart.

9. A method as claimed in claim 8, comprising:

classifying the subscribers into at least two categories; and

setting a different threshold value for each category.

10. A method as claimed in claim 8, wherein said threshold value (N_MAX) is subscriber-specific and depends on the previous frequency of location updatings by the same subscriber.

11. A method as claimed in claim 1, comprising:

classifying the subscribers into at least two categories; and

setting a different threshold value for each category.

12. A method as claimed in claim 1, wherein said threshold value (N_MAX) is subscriber-specific and depends on the previous frequency of location updatings by the same subscriber.

14. A network element as claimed in claim 10, wherein said network element is a mobile switching center.

13. A network element of a mobile communication network, to which the means (HLR, VLR) are functionally coupled to handle the location updatings of a subscriber, wherein the network element (MSC) further comprises:

means (60) for monitoring, subscriber-specifically, the number (N) of at least one type of location updatings during a predetermined monitoring period;

means (628) for comparing said number (N) to a predetermined threshold value (N_MAX);

means for maintaining a group of special subscribers; and

means (630) for generating a signal indicative of said number (N) of location updatings exceeding the predetermined threshold value (N_MAX) in response to said number (N) of location updatings exceeding the predetermined threshold value (N_MAX) only when a subscriber is not one of said special subscribers.