Methods and devices for facilitating emergency calls over wireless communication systems

1. A method implemented by a first gateway node for processing an emergency call, comprising:

receiving an emergency call request initiated from a terminal device over an untrusted non-3GPP based access network, wherein the emergency call request includes an emergency network access identifier constructed by the terminal device;

detecting an event of the emergency call depending upon the emergency network access identifier;

selecting for the terminal device an emergency access point name that identifies an external network providing an emergency call service;

establishing for the terminal device an emergency call session with a second gateway node interfacing with the external network which is identified by the selected emergency access point name; and

transmitting to the terminal device a plurality of parameters of the selected emergency access point.

2. The method according to claim 1 , further comprising informing the terminal device of the selected emergency access point name, thereby facilitating potential handover from the untrusted non-3GPP based access network to a 3GPP based access network.

3. The method according to claim 1 , wherein establishing an emergency call session for the terminal device comprises:

sending to the second gateway node a create session request including the selected emergency access point name, thereby enabling the second network node to identify the emergency call session.

4. The method according to claim 1 , wherein establishing an emergency call session for the terminal device comprises:

authenticating the terminal device based on an equipment identity of the terminal device.

5. A method implemented by a terminal device for initiating an emergency call over an untrusted non-3GPP based access network, comprising:

constructing an emergency network access identifier;

sending to a first gateway node an emergency call request including the constructed emergency network access identifier;

establishing, via the first gateway node, an emergency call session with a second gateway node interfacing with an external network providing an emergency call service; and

receiving from the first gateway node a plurality of parameters of a selected emergency access point.

6. The method according to claim 5 , wherein the emergency network access identifier includes a predetermined indicator of the emergency call.

7. The method according to claim 5 , further comprising: receiving from the first gateway node an emergency access point name, thereby facilitating potential handover from the untrusted non-3GPP based access network to a 3GPP based access network.

8. A method implemented by a network node of a 3GPP based access network for processing an emergency call, comprising:

receiving an emergency call request initiated from a terminal device over a 3GPP based access network;

selecting for the terminal device an emergency access point name that identifies an external network providing an emergency call service;

establishing an emergency call session with a second gateway node interfacing with the external network that is identified by the selected emergency access point name; and

transmitting to the terminal device a plurality of parameters of the selected emergency access point.

9. The method according to claim 8 , further comprising:

informing the terminal device of the selected emergency access point name, thereby facilitating potential handover from the 3GPP based access network to an untrusted non-3GPP based access network.

10. A first gateway node operably for processing an emergency call, comprising:

a receiving unit configured to receive an emergency call request initiated from a terminal device over an untrusted non-3GPP based access network, wherein the emergency call request includes an emergency network access identifier constructed by the terminal device;

a detecting unit configured to detect an event of the emergency call depending upon the emergency network access identifier;

a selecting unit configured to select for the terminal device an emergency access point name that identifies an external network providing an emergency call service; and

a session establishing unit configured to establish for the terminal device an emergency call session with a second gateway node interfacing with the external network which is identified by the selected emergency access point name and to transmit to the terminal device a plurality of parameters of the selected emergency access point.

11. The first gateway node according to claim 10 , further comprising:

a transmitting unit configured to inform the terminal device of the selected emergency access point name, thereby facilitating potential handover from the untrusted non-3GPP based access network to a 3GPP based access network.

12. The first gateway node according to claim 10 , wherein the session establishing unit is further configured to send to the second gateway node a create session request including the selected emergency access point name, thereby enabling the second network node to identify the emergency call session.

13. The first gateway node according to claim 10 , wherein the session establishing unit is further configured to authenticate the terminal device based on an equipment identity of the terminal device.

14. A terminal device operably for initiating an emergency call over an untrusted non-3GPP based access network, comprising:

an identifier constructing unit configured to construct an emergency network access identifier;

a transmitting unit configured to send to a first gateway node an emergency call request including the constructed emergency network access identifier; and

a session establishing unit configured to establish, via the first gateway node, an emergency call session with a second gateway node interfacing with an external network providing an emergency call service and to receive, from the first gateway node, a plurality of parameters of a selected emergency access point.

15. The terminal device according to claim 14 , wherein the emergency network access identifier includes a predetermined indicator of the emergency call.

16. The terminal device according to claim 14 , further comprising:

a receiving unit configured to receive from the first gateway node an emergency access point name, thereby facilitating potential handover from the untrusted non-3GPP based access network to a 3GPP based access network.

17. A network node of a 3GPP based access network operably for processing an emergency call, comprising:

a receiving unit configured to receive an emergency call request initiated from a terminal device over a 3GPP based access network;

a selecting unit configured to select for the terminal device an emergency access point name that identifies an external network providing an emergency call service; and

a session establishing unit configured to establish an emergency call session with a second gateway node interfacing with the external network that is identified by the selected emergency access point name and to transmit to the terminal device a plurality of parameters of the selected emergency access point.

18. The network node according to claim 17 , further comprising:

a transmitting unit configured to inform the terminal device of the selected emergency access point name, thereby facilitating potential handover from the 3GPP based access network to an untrusted non-3GPP based access network.

19. A first gateway node operably for processing an emergency call, comprising a processor adapted to:

cause to receive an emergency call request initiated from a terminal device over an untrusted non-3GPP based access network, wherein the emergency call request includes an emergency network access identifier constructed by the terminal device;

cause to detect an event of the emergency call depending upon the emergency network access identifier;

cause to select for the terminal device an emergency access point name that identifies an external network providing an emergency call service;

cause to establish for the terminal device an emergency call session with a second gateway node interfacing with the external network which is identified by the selected emergency access point name; and

cause to transmit to the terminal device a plurality of parameters of the selected emergency access point.

20. The first gateway node according to claim 19 , further comprising a memory, wherein the memory includes instructions executable by the processor.

21. A terminal device operably for initiating an emergency call over an untrusted non-3GPP based access network, comprising a processor adapted to:

cause to construct an emergency network access identifier;

cause to send to a first gateway node an emergency call request including the constructed emergency network access identifier;

cause to establish, via the first gateway node, an emergency call session with a second gateway node interfacing with an external network providing an emergency call service; and

cause to receive, from the first gateway node, a plurality of parameters of a selected emergency access point.

22. The terminal device node according to claim 21 , further comprising a memory, wherein the memory includes instructions executable by the processor.

23. A network node of a 3GPP based access network operably for processing an emergency call, comprising a processor adapted to:

cause to receive an emergency call request initiated from a terminal device over a 3GPP based access network;

cause to select for the terminal device an emergency access point name that identifies an external network providing an emergency call service;

cause to establish an emergency call session with a second gateway node interfacing with the external network that is identified by the selected emergency access point name; and

cause to transmit to the terminal device a plurality of parameters of the selected emergency access point.

24. The network node according to claim 23 , further comprising a memory, wherein the memory includes instructions executable by the processor.