System and method for call tracing

• US 6,009,321 A
• Filed: 07/07/1997
• Issued: 12/28/1999
• Est. Priority Date: 07/07/1997
• Status: Expired due to Fees

• Current Assignee: Nortel Networks Limited (Nortel Networks Corporation)
• Original Assignee: Northern Telecom Limited (Nortel Networks Corporation)
• Inventors: Wang, Jin, Idrissi, Yahya, Wilding, David, Hemmer, Maria
• Primary Examiner(s): Chin, Wellington
• Assistant Examiner(s): Jama, Isaak R.
• Application Number:
  US08/888,767
• Time in Patent Office: 904 Days
• Field of Search: 455/415, 455/414, 455/432, 455/433, 455/560, 455/461, 455/410, 379/211, 379/213, 379/244, 379/219, 379/133
• US Class Current: 455/410
• CPC Class Codes: H04L 63/30 for supporting lawful interception, monitoring or retaining of communications or communication related information circuit switched telephony call monitoring H04M3/2281
• CPC Class Codes: H04W 24/00 Supervisory, monitoring or testing arrangements

Abstract

A system and method for tracing calls, such as those terminating in a wireless telephone system, is disclosed. The system is part of a communication network that uses a switch connected to a caller. The switch extracts information about the caller such as a calling party number and other information useful for tracing the call. Once the information has been extracted, the switch sends the information to a storage device associated with the called party, such as a home location register. The storage device creates a log of the call, storing all the extracted information. When the call is to be traced, a device capable of accessing the storage device can easily retrieve the stored information and thereby identify and locate the caller.

Claims

1. A method for tracing a call to a mobile called station, the method comprising the steps of:

receiving a request to trace the call after the call was initiated;

determining a predetermined storage device directly from subscription data of the mobile called station, the storage device being previously used to complete the call;

contacting the storage device; and

retrieving information about a caller from the storage device, the information being previously extracted from the caller when the caller initiated the call to the mobile called station.

2. The method of claim 1 wherein the steps of extracting, contacting, and providing are performed for every call to the called station.

3. The method of claim 1 wherein the information includes a number identifying the caller.

4. The method of claim 1 wherein the information identifies a location of the caller.

5. The method of claim 1 wherein the mobile switch is an originating switch for the called station and the storage device is a home location register associated with the originating switch.

6. The method of claim 1 wherein the storage device is a visitor location register associated with a second switch that the called station is visiting.

7. A system for tracing a caller having originated a call to a called station in a wireless network, the system comprising:

a mobile switch connected to the called station for extracting information about the caller and providing the information to a storage device associated with the mobile switch when the call was being originated.

the storage device for receiving and logging the information from the switch and for facilitating the completion of the call, the storage device being associated with the called station; and

means for identifying the storage device directly from the called station and retrieving the information from the storage device.

8. The system of claim 7 wherein the switch extracts the information and provides the information to the storage device and uses the storage device to place the call for every call to the called station.

9. The system of claim 7 wherein the information includes a number identifying the caller.

10. The system of claim 7 wherein the information identifies a location of the caller.

11. The system of claim 7 wherein the called station is a mobile unit and a subscriber to a network that includes the switch.

12. The system of claim 11 wherein the storage device is a home location register associated with the called station.

13. The system of claim 11 wherein the storage device is a visitor location register associated with a serving switch with which the called station is linked.

14. A system for tracing a call between a caller and a mobile unit, the system comprising:

a first mobile switching center ("MSC") of a wireless network to which the mobile unit is a subscriber;

a register for receiving and storing information from the first MSC;

a network interconnecting the first MSC with the register;

means for extracting call information at the MSC upon call initiation, and providingthe information to the register for storage;

means for identifying the register by subscription information of the mobile unit upon receipt of a trace request;

means for retrieving the call information from the register, the call information identifying the caller and thereby tracing the call.

15. The system of claim 14 further comprising a second MSC for servicing and linking to the mobile unit, the second MSC also being interconnected by the network.

16. The system of claim 14 wherein the information includes a number identifying the caller.

17. The system of claim 14 wherein the caller is a land-line telephone.

18. The system of claim 14 wherein the register is a home location register that stores additional information for the mobile unit.

19. The system of claim 15 wherein the register is a visitor location register associated with the second MSC.