System and method for the early detection of cellular telephone piracy

• US 6,161,006 A
• Filed: 12/22/1997
• Issued: 12/12/2000
• Est. Priority Date: 12/22/1997
• Status: Expired due to Term

• Current Assignee: Optis Wireless Technology, LLC (Brevet Capital)
• Original Assignee: Ericsson, Inc. (Telefonaktiebolaget LM Ericsson)
• Inventors: Balachandran, Shridharan
• Primary Examiner(s): Tsang, Fan
• Assistant Examiner(s): SOBUTKA, PHILIP
• Application Number:
  US08/996,089
• Time in Patent Office: 1,086 Days
• Field of Search: 455/410, 455/411, 455/404, 455/456, 455/403, 455/422, 455/515, 455/528, 455/435, 455/433, 455/432
• US Class Current: 455/410
• CPC Class Codes: H04W 12/0431 Key distribution or pre-distribution; Key agreement
• CPC Class Codes: H04W 12/126 Anti-theft arrangements, e.g. protection against subscriber identity module [SIM] cloning
• CPC Class Codes: H04W 12/30 Security of mobile devices; Security of mobile applications
• CPC Class Codes: H04W 12/63 Location-dependent; Proximity-dependent

Abstract

A method and system for early piracy detection in a cellular telecommunications network is disclosed. When in idle mode, a network subscriber Mobile Station (MS) transmits a Current Location Identifier message (CLID) on a pseudo-random basis. The CLID, which contains MS identifying information, is picked up by the network and relayed to the Mobile Switching Center (MSC) covering the area in which the MS is currently located. When it receives the CLID, the MSC generates an MS-CLID message containing the CLID and the identifier of the nodes through which it has passed, including that of the MSC itself. The MS-CLID message is then sent to the system Home Location Register (HLR), which compares the MS identification and location information to that stored in its database. The system generates a piracy alarm when the comparison determines that another caller using the same identity is currently active or that a call being initiated is originating from a location distant to the last reported location of the legitimate MS, allowing the system operator to take action prior to the loss of inordinate amounts of air time.

Claims

1. A method for detecting piracy of a mobile station within a cellular telecommunications system, said method comprising the steps of:

maintaining, within a database of said telecommunications system, an activity flag associated with said mobile station, said activity flag being set when said mobile station is active;

transmitting, automatically by said mobile station, an identification signal a plurality of times while said mobile station is idle, wherein said mobile station, if in a powered-off condition at the time said identification signal is scheduled for transmission, automatically powers-on for a period at least long enough for said transmission to occur;

determining, after at least one of said identification signal transmissions, whether said activity flag for said idle mobile station is active; and

generating an alarm signal if said activity flag for said idle mobile station is active.

2. The method of claim 1, wherein said identification signal is transmitted by said idle mobile station at pseudo-randomly spaced intervals.

3. The method of claim 2, wherein said pseudo-random intervals are determined using an algorithm that is stored in both said mobile station and said database, and further comprising the steps of:

determining, after at least one of said identification signal transmissions, whether said at least one identification signal transmission occurred at a time predictable by said algorithm; and

generating an alarm signal if said at least one identification signal transmission was not sent at a time predictable by said algorithm.

4. The method of claim 2, further comprising the step of varying the frequency of said pseudo-random transmissions by a control signal sent to said mobile station.

5. The method of claim 4, wherein said varying step varies said frequency of said pseudo-random transmissions based on the areas in which said mobile station had been recently operating.

6. The method of claim 1, further comprising the steps of:

maintaining, within a database of said telecommunications system, a last-reported location of said mobile station;

determining, after said at least one identification signal transmission, a current location of said mobile station within said telecommunicating system;

comparing said current location of said mobile station after said identification signal transmission to said last-reported location; and

generating an alarm signal if said current location of said mobile station is different from said last reported location.

7. The method of claim 1, further comprising the steps of:

determining, after said at least one identification signal transmission, the identification signal path, wherein said identification signal path includes an identifier corresponding to at least one of the nodes of said telecommunication system through which said identification signal has been most recently transmitted;

maintaining, within a database of said telecommunications system, said identification signal path;

updating, after said comparison step, said last reported location of said mobile station within said location database to the current location;

transmitting, to said mobile station, said identification signal path;

storing, within a memory of said mobile station, said identification signal path as it is received;

transmitting, from said mobile station, a second identification signal, wherein said second identification signal includes said updated identification signal path last received by said mobile station;

comparing said identification signal path within said second identification signal to said identification path in said database of said telecommunications system; and

generating an alarm signal if said identification signal path within said second identification signal is different from said identification signal path in said database of said telecommunications network.

8. The method of claim 1, wherein said database of said telecommunications system is located within a home location register of said telecommunications system.

9. The method of claim 1, wherein said determining step is performed within an authentication register in communication with the home location register of said telecommunications network.

10. The method of claim 1, wherein said activity flag indicates whether the mobile station is active based on a query to visitor location registers in communication with said telecommunications system.

11. The method of claim 10, wherein said query is made after at least one of said identification signal transmissions.

12. The method of claim 1, wherein said activity flag is set based on a notification provided by visitor location registers when said mobile station becomes voice-active or inactive.

13. The method of claim 1, additionally comprising the step of determining a specific area in which a suspect clone is operating.

14. The method of claim 13, wherein said suspected operating area is determined by a signal loop-back time triangulation process.

15. The method of claim 1, wherein said alarm signal causes a piracy report to be generated.

16. A method for detecting piracy in a telecommunications system, said method comprising the steps of:

maintaining, within a home location register, a location database containing a plurality of locations of a corresponding plurality of active mobile stations associated with the telecommunications system;

transmitting, from a given one of said mobile stations, a current location identifier, said current location identifier corresponding to said given mobile station;

relaying said current location identifier of said given mobile station to said home location register;

determining, within said home location register upon receipt of said current location identifier, whether an active mobile station identifier, for at least one of said locations in said location database of said active mobile stations, matches said current location identifier;

generating an alarm if, in said step of determining, said current location identifier matches said active mobile station identifier;

determining the location of said given mobile station transmitting said current location identifier;

updating said location database in the home location register to said current location identifier location;

transmitting said current location identifier location to said given mobile station, said given mobile station storing said current location identifier location in a memory therein;

transmitting from said given mobile station, a second current location identifier, said second current location identifier including said stored current location identifier;

comparing said stored current location identifier in said second current location identifier to said current location identifier for said given mobile station in said location database; and

generating said alarm if the stored current location identifier within said second current location identification does not match said current location identifier for said given mobile station in said location database of said home location register.

17. The method of claim 16, further comprising the step of:

varying the frequency of said transmission of said current location identifier based on the areas in which said mobile station had been recently operating.

18. The method of claim 16, further comprising the step of determining the location of a suspected clone whenever said alarm is generated.

19. The method of claim 18, wherein said alarm caused a piracy report to be generated.

20. The method of claim 16, further comprising the steps of:

counting the number of current location identifiers transmitted by said given mobile station within a predetermined period; and

alerting the system operator if the number of transmissions counted in said counting step exceeds a predetermined threshold.

21. A cellular telecommunications system for detecting piracy of a mobile station, said system comprising:

a home location register having a location database containing the last reported location of a plurality of mobile stations associated with said home location register;

a signal generator in at least one of said mobile stations for sending respective identification messages to said home location register said signal generator varying the frequency of transmission of said respective identification messages based on the areas in which said mobile station had been recently operating;

determining means for determining if said identifier corresponding to a given one of said mobile stations matches the identifier corresponding to at least one other active mobile station sending said respective identification messages; and

an alarm generator for generating an alarm if said given one mobile station identifier matches said other active mobile station identifier.

22. The system of claim 21, wherein said home location register determines the current location of said given mobile station and transmits said current location to said mobile station, and further comprising a storage location in said mobile station for storing location information sent to it from said home location register.

23. A method for detecting piracy of a mobile station within a cellular telecommunications system, said method comprising the steps of:

maintaining, within a database of said telecommunications system, an activity flag associated with said mobile station, said activity flag being set when said mobile station is active;

transmitting, by said mobile station, an identification signal a plurality of times while said mobile station is idle, wherein said identification signal is transmitted by said idle mobile station at pseudo-randomly space intervals;

varying the frequency of said pseudo-random transmissions, by a control signal sent to said mobile station, based on the areas in which said mobile station had been recently operating;

determining, after at least one of said identification signal transmissions, whether said activity flag for said idle mobile station is active; and

generating an alarm signal if said activity flag for said idle mobile station is active.