Technique for enabling emergency call callback of a terminal without a valid subscriber identity

• US 20020111159A1
• Filed: 02/15/2001
• Published: 08/15/2002
• Est. Priority Date: 02/15/2001
• Status: Active Grant

• Current Assignee: Nokia Networks (Nokia Corporation)
• Original Assignee: Nokia Networks (Nokia Corporation)
• Inventors: Faccin, Stefano M., Rajaniemi, Jakko
• Granted Patent: US 6,571,092 B2
• Time in Patent Office: Days
• US Class Current: 455/445
• CPC Class Codes: H04M 2242/04 for emergency applications
• CPC Class Codes: H04M 3/5116 for emergency applications
• CPC Class Codes: H04W 4/90 Services for handling of emergency or hazardous situations, e.g. earthquake and tsunami warning systems [ETWS]
• CPC Class Codes: H04W 76/50 for emergency connections

Abstract

A technique for enabling a callback by a called party, such as an emergency center, of a terminal, such as a mobile terminal having no identity and no CBN (Call Back Number), in the case of an emergency call, for example, includes allocating a temporary identity to the terminal and then allocating an IP address to the terminal and storing the association between the temporary identity and the allocated IP address. A CBN is that allocated to the mobile terminal and the association between the CBN and the allocated IP address is also stored. A call is then setup between the terminal and the called party. Upon the call between the terminal and the called party being dropped, the IP address associated with the allocated CBN of the terminal is retrieved as is the stored temporary identity corresponding to the retrieved IP address. Paging is then forwarded to the terminal using the stored temporary identity and a call is again setup between the terminal and the called party.

Claims

1. A method of enabling a callback by a called party of a terminal having no call back identity, the method comprising:

requesting connection from the terminal to a called party,

detecting that the terminal has no identity enabling callback;

allocating a temporary identity to the terminal, the temporary identity comprising a call back identity which can be used by the called party to identify the terminal for terminating connections;

setting up a connection between the terminal and the called party and indicating the call back identity to the called party.

2. The method of claim 1, wherein, upon the connection between the terminal and the called party being dropped, the method further comprising:

the called party requesting a connection using the call back identity of the terminal;

receiving the connection request including the call back identity;

retrieving the temporary identity of the terminal; and

establishing a connection to the terminal.

3. The method of claim 1, wherein the temporary identity comprises an IP address for the terminal.

4. The method of claim 1, wherein the call back identity comprises an E.164 number.

5. The method of claim 1, wherein the call back identity comprises an IP address.

6. The method of claim 1, wherein the temporary identity comprises an IMSI (International Mobile Subscriber Identity).

7. The method of claim 2, wherein the temporary identity comprises an IMSI (International Mobile Subscriber Identity).

8. The method of claim 1, wherein the temporary identity comprises a TMSI (Temporary Mobile Subscriber Identity).

9. The method of claim 2, wherein the temporary identity comprises a TMSI (Temporary Mobile Subscriber Identity).

10. The method of claim 1, wherein the terminal has an IP address enabling terminating connections to the terminal but no CBN (Call Back Number), the method further comprising:

detecting that the terminal has no CBN;

allocating a CBN to the terminal upon detecting that the mobile terminal has no CBN and storing association between the CBN and the IP address of the terminal;

setting up a call between the terminal and the called party, and

indicating the call back number to the called party.

11. The method of claim 10, wherein the CBN comprises an E. 164 number.

12. The method of claim 1, wherein:

the terminal requests the connection to the called party by forwarding a PDP context request to an SGSN (Server General Packet Radio Service Node);

the SGSN allocates a temporary identity to the terminal;

the SGSN forwards the activate PDP context request to a GGSN (Gateway General Packet Radio Service Node);

the GGSN allocates an IP address to the terminal and stores association between the temporary identity and the allocated IP address;

the GGSN forwards the allocated IP address to the terminal via the SGSN;

a call setup is communicated between the terminal and a CSCF (Call State Control Function) using the allocated IP address;

the CSCF detects that the terminal is not registered and allocates a CBN (Call Back Number) and stores association between CBN and allocated IP address; and

the CSCF sets up a call between the terminal and the called party.

13. The method of claim 12, wherein, upon the call between the terminal and the called party being dropped, the method further comprising:

communicating a call setup from the called party to the CSCF;

the CSCF retrieving the IP address associated with the CBN and then forwarding the call setup to the GGSN;

the GGSN retrieving the stored identity for the IP address and forwarding paging to the terminal via the SGSN; and

again setting up a call between the terminal and the called party by providing a new PDP context activation.

14. The method of claim 12, wherein the temporary identity comprises an IMSI (International Mobile Subscriber Identity).

15. The method of claim 13, wherein the temporary identity comprises an IMSI (International Mobile Subscriber Identity).

16. The method of claim 12, wherein the temporary identity comprises a TMSI (Temporary Mobile Subscriber Identity).

17. The method of claim 13, wherein the temporary identity comprises a TMSI (Temporary Mobile Subscriber Identity).

18. The method of claim 12, wherein the CBN comprises an E. 164 number.

19. The method of claim 13, wherein the CBN comprises an E. 164 number.

20. A communication system for enabling a callback by a called party of a terminal having no call back identity, the system comprising:

a receiving means for receiving a request for a connection from the terminal to a called party;

a detecting means for detecting that the terminal has no identity enabling callback;

an allocation means for allocating a temporary identity to the terminal, the temporary identity comprising a call back identity which can be used by the called party to identify the terminal for terminating connections;

a connection control means for setting up a connection between the terminal and the called party; and

an indication means for indicating the call back identity to the called party.

21. A network node of a communication system for enabling a callback by a called party of a terminal having no call back identity, the network node comprising:

a receiving means for receiving a request for a connection from the terminal to a called party;

a detecting means for detecting that the terminal has no identity enabling callback

an allocation means for allocating a temporary identity to the terminal, the temporary identity comprising a call back identity which can be used by the called party to identify the terminal for terminating connections;

a connection control means for setting up a connection between the terminal and the called party; and

an indication means for indicating the call back identity to the called party.