NON-VALIDATED EMERGENCY CALLS FOR ALL-IP 3GPP IMS NETWORKS

• US 20110194553A1
• Filed: 02/09/2010
• Published: 08/11/2011
• Est. Priority Date: 02/18/2009
• Status: Active Grant

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Nguyen, Steven, Sahin, Serdar
• Granted Patent: US 9,515,850 B2
• Time in Patent Office: Days
• US Class Current: 370/352
• CPC Class Codes: H04L 12/66 Arrangements for connecting between networks having differing types of switching systems, e.g. gateways
• CPC Class Codes: H04L 65/1096 Supplementary features, e.g. call forwarding or call holding systems providing special services or facilities to telephony subscribers H04M3/42
• CPC Class Codes: H04M 2242/04 for emergency applications
• CPC Class Codes: H04W 12/06 Authentication
• 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 76/10 Connection setup
• CPC Class Codes: H04W 76/50 for emergency connections

Abstract

An emergency call in an all Internet Protocol (IP) network having GPRS access is able to be completed without a valid SIM. A valid Subscriber Identity Module is substituted for the missing or invalid SIM only when an emergency call is attempted. The emergency call is either sent via an IMSI from an embedded SIM provided by the UE making the emergency call, or the emergency call is modified with an IMSI substituted by an Emergency SIM Pool Function prior to being sent to the HLR for validation. The SIM is valid for the UE'"'"'s emergency call so the emergency call is completed because the UE is considered validated by the network.

Claims

1. A method for completing an emergency call in an all Internet Protocol (IP) network having GPRS access, the method comprising:

implementing, in a node in the IP network, a pool of substitute Subscriber Identity Modules (SIMs) that are designated as an Emergency SIM Pool Function (ESPF);

receiving an emergency call request from a User Equipment with no SIM card or an invalid SIM card;

providing or substituting a valid SIM from the ESPF for the missing or invalid SIM of the UE;

forwarding the call request with the valid SIM to the IMS network'"'"'s HLR, wherein the substitute SIM is authenticated; and

completing the emergency call by routing the authenticated emergency request message to a Public Safety Answering Point.

2. The method of claim 1, wherein if the UE lacks the SIM card, the UE generates a subsequent emergency call request that includes an emergency IMSI formed by concatenating the last twelve digits of the International Mobile Equipment Identity (IMEI) of the UE with the emergency call request.

3. The method of claim 2, further comprising

presenting the emergency request message to the UE'"'"'s home network HLR and upon rejection as invalid, the ESPF intercepting a second request message from the UE comprising the emergency IMSI, and

sending the emergency request message with the valid SIM, including a new IMSI, to the HLR.

4. The method of claim 1, wherein the pool of substitute SIMs comprises valid SIMs, set aside by the operator of the IP network, for the purpose of allowing a UE with an invalid or missing SIM card to complete an emergency call.

5. The method of claim 1, wherein the node is a Serving GPRS Support Node (SGSN), a Radio Access Network (RAN) node or a standalone node.

6. The method of claim 1, wherein, if the UE is in a visited network, the step of receiving the emergency call further comprises:

confirming with the UE'"'"'s home network HLR if the SIM of the UE is valid and if so, directing the emergency call to a Public Safety Answering Point (PSAP);

if the SIM is not valid, substituting a valid SIM, from the ESPF, having a valid IMSI for the invalid SIM; and

sending the emergency request with the valid SIM to the visited network'"'"'s SGSN.

7. The method of claim 1, the step of forwarding the call request with the valid SIM, further comprising;

receiving the authenticated emergency request message in the ESPF with the authenticated information for the RAN, wherein the ESPF responds to the authentication message from the SGSN with an expected response directly to the SGSN without routing through the RAN.

8. The method of claim 1, further comprising

routing the call to the ESPF, the ESPF modifying Attach and PDP (Packet Data Protocol) Context Request messages by inserting IMSI/SRES/XRES (International Mobile Subscriber Identity)/(Signed RESponse)/(eXpected user RESponse) as required.

9. The method of claim 1, further comprising disabling ciphering for the non-validated Emergency call.

10. A User Equipment, for completing an emergency call in an all Internet Protocol (IP) network, the UE comprising:

a SIM card, wherein Attach and PDP Context Activation are executed by the UE if the SIM card is valid; and

an embedded SIM card for executing Attach and PDP Context Activation when the SIM card is either missing or invalid as determined by the UE Home Location Register; and

a processor utilizing stored instructions for

detecting an emergency call by the UE;

determining whether the UE'"'"'s SIM card is either missing or invalid, and if so,

substituting the valid, embedded SIM for the missing or invalid SIM of the UE in the emergency call request, and

forwarding the call request with the valid SIM to the IP network'"'"'s HLR, wherein the substitute SIM is authenticated, wherein the emergency call is completed by routing the authenticated emergency request message to a Public Safety Answering Point.

11. The UE of claim 10, the embedded SIM being a special SIM installed in the UE during the manufacturing process for the purpose of making emergency calls.

12. A node in an IP network for completing an emergency call in an Internet Protocol (IP) network having GPRS access, the node comprising:

transceiver means for transmitting and receiving an emergency call request; and

a processor utilizing stored instructions for

utilizing an embedded, valid, substitute Subscriber Identity Module (SIM) in a User Equipment (UE), only if the UE is missing a SIM card or has an invalid SIM card;

receiving a PDP Context Request from the UE;

sending the PDP Context Request with the embedded, valid SIM to the home HLR, thereafter the substitute SIM being authenticated; and

completing the emergency call by routing the authenticated emergency request message to a Public Safety Answering Point.

13. The node of claim 12, wherein if the UE lacks the SIM card, the node receives a subsequent emergency call request generated by the UE that includes an emergency IMSI formed by concatenating the last twelve digits of the International Mobile Equipment Identity (IMEI) of the UE with the emergency call request.

14. The node of claim 13, wherein the transceiver means further comprises:

means for sending the emergency request message to the UE'"'"'s home network HLR and upon rejection as invalid, the ESPF intercepting a second request message from the UE comprising the emergency IMSI, and

means for sending the emergency request message with the valid SIM, including a new IMSI, to the HLR.

15. The node of claim 12, wherein the pool of substitute SIMs comprises valid SIMs, set aside by the operator of the IP network, for the purpose of allowing a UE with an invalid or missing SIM card to complete an emergency call.

16. The node of claim 12, wherein the node is a Serving GPRS Support Node (SGSN), a Radio Access Network (RAN) node or a standalone node.

17. The node of claim 12, wherein, if the UE is in a visited network, the means for receiving the emergency call further comprises:

means for confirming with the UE'"'"'s home network HLR if the SIM of the UE is valid and if so, directing the emergency call to a Public Safety Answering Point (PSAP);

if the SIM is not valid, means for substituting a valid SIM, from the ESPF, having a valid IMSI for the invalid SIM; and

means for sending the emergency request with the valid SIM to the visited network'"'"'s SGSN.

18. The node of claim 12, the step of forwarding the call request with the valid SIM, further comprising;

means for receiving the authenticated emergency request message in the ESPF with the authenticated information for the RAN, wherein the ESPF responds to the authentication message from the SGSN with an expected response directly to the SGSN without routing through the RAN.

19. The node of claim 12, further comprising

routing means for routing the call to the ESPF, the ESPF modifying Attach and PDP (Packet Data Protocol) Context Request messages by inserting IMSI/SRES/XRES (International Mobile Subscriber Identity)/(Signed RESponse)/(eXpected user RESponse) as required.

20. The node of claim 12, further comprising means for disabling ciphering for the non-validated Emergency call.