Tracking of mobile terminal equipment in a mobile communications system

• US 6,636,742 B1
• Filed: 06/22/2000
• Issued: 10/21/2003
• Est. Priority Date: 12/23/1997
• Status: Expired due to Term

• Current Assignee: CommWorks Solutions, LLC (IP Investments Group LLC)
• Original Assignee: Sonera Oyj
• Inventors: Torkki, Markus, Gröhn, Tuomo
• Primary Examiner(s): VUONG, QUOCHIEN B
• Application Number:
  US09/599,201
• Time in Patent Office: 1,216 Days
• Field of Search: 455/422, 455/432, 455/433, 455/435, 455/456, 455/457, 455/461, 455/575
• US Class Current: 455/456.1
• CPC Class Codes: H04W 60/00 Affiliation to network, e.g. registration; Terminating affiliation with the network, e.g. de-registration
• CPC Class Codes: H04W 8/04 Registration at HLR or HSS [Home Subscriber Server]
• CPC Class Codes: H04W 8/06 Registration at serving network Location Register, VLR or user mobility server
• CPC Class Codes: H04W 8/12 between location registers or mobility servers

Abstract

Drawbacks of known methods of location determination are that the location can be determined only when the mobile station is setting up a call and during the call. The invention utilises that characteristic feature of mobile telephone systems that the location of the terminal is always known to the system with location area precision and that the geographical network topology is known to the network planning system. The tracing system includes three functional parts: a first part provides the mobile telephone system with the connection number of the traced terminal as an enquiry input, and in response to the input it receives information on where the subscriber'"'"'s location area should be enquired for. The second functional part asks for the subscriber'"'"'s location area and receives in response a location area code, which identifies the location area unambiguously. The third functional part searches the location area table for information corresponding with the subscriber'"'"'s location area and attends to reporting on the results. The location area table is formed on a basis of cell topology information which is available in advance from the network planning system, which converts the location area identity into an area name in plain language which is bound to a map. Enquiries may be made at desired intervals and the result may be stored in a tracing file. From this a report can be formed from which it is possible easy to find out the subscriber'"'"'s movements with location area precision.

Claims

1. Method of determination of the location area of a terminal in a cellular mobile telephone network including

at least one home location register (HLR) wherein permanent subscriber information is stored, including the subscriber number (MSISDN) of the terminal,

at least one mobile switching centre (MSC) and a related visitor location register (VLR), wherein subscriber information about terminals located in a switching centre area comprising of several location areas is temporarily stored, whereby the subscriber information also contains an identity of that traffic area wherein each terminal is located,

a network management system which can make enquiries to the home location register and to the visitor location register,

a network planning system storing the geographical location information of cell areas for each location area and location area identity information, wherein:

location area information is sought from the network planning system,

using the location area information, a permanent location area table is formed, wherein desired parameters are added to the identity of each location area, and that in the determination of the location area of the terminal;

the network management system is requested to ask the home location register which is the visitor location register number in the subscriber information of the subscriber number (MSISDN) of the terminal,

the network management system is requested to ask the stated visitor location register which is the location area identity in the subscriber'"'"'s subscriber information,

the parameters relating to the location area identity are sought from the location area table.

2. Method as defined in claim 1, wherein

from the cell areas of the location area an equivalent location area is formed whose midpoint is the centre of gravity of the cell areas and whose area is the area of the cell areas,

the equivalent location area is placed as a parameter in the location area table.

3. Method as defined in claim 1, wherein

a real geographical name is given to the equivalent location area and the name is placed as a parameter in the location area table.

4. Method as defined in claim 1, wherein the date and time of day are placed as a parameter in the location area table.

5. Method as defined in claim 1, wherein the visitor location register number obtained from the home location register is converted into a register name and the network management system is requested to make this enquiry of a visitor location register carrying this name.

6. Method as defined in claim 1, wherein the network management system is requested repeatedly to ask for the location area identity and at a predetermined frequency.

7. Method as defined in claim 1, wherein in response to an error message sent by the home location register, the network management system is requested to make a new enquiry to the home location register.

8. Method as defined in claim 6, wherein the parameters relating to the location area identity are placed as a record and a tracing report is formed of successive records.

9. Method as defined in claim 8, wherein a record is placed in the tracing report only when there is a change in the subscriber'"'"'s location area identity.

10. Method as defined in claim 8, wherein the network management system is requested to ask the visitor location register also for other subscriber information and this information is placed in the report.

11. Method as defined in claim 1, wherein only the country code is placed in the record of the tracing report, if the terminal is a roaming subscriber in the network of a foreign operator.

12. Method as defined in claim 6, wherein in response to an error message sent by the home location register, the network management system is requested to make a new enquiry to the home location register.

13. A tracing system for determination of the location area of a terminal in a cellular mobile telephone network including

at least one home location register (HLR) wherein permanent subscriber information is stored, including the subscriber number (MSISDN) of the terminal,

at least one mobile switching centre (MSC) and the related visitor location register (VLR) wherein subscriber information on terminals located in a switching centre area including several location areas is temporarily stored, whereby the subscriber information also contains the identity of that traffic area wherein each terminal is located,

a network management system which may make enquiries to the home location register and to the visitor location register,

a network planning system storing the geographical location information of cell areas for each location area and the location area identity information, wherein the tracing system is in communication connection with the network management system and it includes:

a location area table containing the location area identity information and as parameters relating to this at least the geographical name given to the location area,

a first functional part, which in response to the input connection number of the terminal requests of the network management system to ask the home location register which in the subscriber information is the visitor location register number relating to the subscriber number (MSISDN),

a second functional part, which in response to the visitor location register number requests of the network management system to ask the stated visitor location register which is the location area identity in the subscriber'"'"'s subscriber information,

a third functional part, which in response to the location area identity searches the location area table for the parameters relating to the location area identity.

14. Tracing system as defined in claim 13, wherein in that the location area table contains the identity of each location area and, in addition, for each identity:

an equivalent location area whose midpoint co-ordinates are the centre of gravity of the real location area,

a set of parameters.

15. Tracing system as defined in claim 13, wherein in response to the visitor location register number given by the first functional part, the second functional part converts the register number into a register name and requests of the network management system to make an enquiry of a visitor location register of this name.

16. Tracing system as defined in claim 13, wherein the second functional part requests of the network management system to ask repeatedly for the location area identity and at a given frequency.

17. Tracing system as defined in claim 13, wherein in response to an error message sent by the home location register, the first functional part requests of the network management system to make a new enquiry to the home location register.

18. Tracing system as defined in claim 13, wherein the third functional part places the parameters relating to the location area identity as a record and forms a tracing report of successive records.

19. Tracing system as defined in claim 13, wherein it works in a general-purpose computer and it is in a local network connection with works stations of the network management system.