VoIP emergency call support

An apparatus, comprising:

• a communications unit;
• at least one processor communicatively coupled to the communications unit and configured to:
• receive, via the communications unit, from an Internet Protocol Multimedia Subsystem (IMS) entity in a visited network, a first request to establish an emergency voice-over-Internet Protocol (VoIP) call for a user equipment (UE) to a Public Safety Answering Point (PSAP), wherein the first request comprises first location information for the UE and a UE identity;
• send, via the communications unit, a second request to a server to obtain routing information for the emergency VoIP call to the PSAP, wherein the second request comprises the first location information and the UE identity;
• receive, via the communications unit, from the server, a first response comprising the routing information, second location information for the UE, and information identifying the server, wherein the first location information comprises a cell identity and the second location information comprises a position estimate for the UE;
• and
• route the emergency VoIP call to the PSAP based on the routing information, comprising sending, via the communications unit directly to the PSAP, a message comprising the UE identity and the information identifying the server, wherein the apparatus is an Emergency Call Session Control Function (E-CSCF);
• and
• a memory coupled to the at least one processor.

An apparatus, comprising:

• means for receiving, from an Internet Protocol Multimedia Subsystem (IMS) entity in a visited network, a first request to establish an emergency voice-over-Internet Protocol (VoIP) call for a user equipment (UE) to a Public Safety Answering Point (PSAP), wherein the first request comprises first location information for the UE and a UE identity;
• means for sending a second request to a server to obtain routing information for the emergency VoIP call to the PSAP, wherein the second request comprises the first location information and the UE identity;
• means for receiving, from the server, a first response comprising the routing information, second location information for the UE, and information identifying the server, wherein the first location information comprises a cell identity and the second location information comprises a position estimate for the UE;
• and
• means for routing the emergency VoIP call to the PSAP based on the routing information, comprising means for sending directly to the PSAP a message comprising the UE identity and the information identifying the server, wherein the apparatus is an Emergency Call Session Control Function (E-CSCF).

A non-transitory computer-readable storage medium comprising instructions, which, when executed by a processor, cause the processor to perform operations, the instructions comprising:

• instructions for receiving, by an Emergency Call Session Control Function (E-CSCF) from an Internet Protocol Multimedia Subsystem (IMS) entity in a visited network, a first request to establish an emergency voice-over-Internet Protocol (VoIP) call for a user equipment (UE) to a Public Safety Answering Point (PSAP), wherein the first request comprises first location information for the UE and a UE identity;
• instructions for sending, by the E-CSCF, a second request to a server to obtain routing information for the emergency VoIP call to the PSAP, wherein the second request comprises the first location information and the UE identity;
• instructions for receiving, by the E-CSCF from the server, a first response comprising the routing information, second location information for the UE, and information identifying the server, wherein the first location information comprises a cell identity and the second location information comprises a position estimate for the UE;
• and
• instructions for routing, by the E-CSCF, the emergency VoIP call to the PSAP based on the routing information, comprising instructions for sending, by the E-CSCF directly to the PSAP, a message comprising the UE identity and the information identifying the server.