TRANSITIONING OF A PACKET-SWITCHED EMERGENCY CALL BETWEEN FIRST AND SECOND TYPES OF WIRELESS ACCESS NETWORKS

• US 20110274012A1
• Filed: 03/16/2010
• Published: 11/10/2011
• Est. Priority Date: 03/16/2009
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Nortel Networks Limited (Nortel Networks Corporation)
• Inventors: Li, Jun, Song, Yi, Jang, Ke-Chi
• Granted Patent: US 9,125,119 B2
• Time in Patent Office: Days
• US Class Current: 370/259
• CPC Class Codes: H04W 36/00226 wherein the core network technologies comprise IP multimedia system [IMS], e.g. single radio voice call continuity [SRVCC]
• CPC Class Codes: H04W 36/0066 of control information between different types of networks in order to establish a new radio link in the target network
• CPC Class Codes: H04W 36/14 Reselecting a network or an air interface
• CPC Class Codes: H04W 36/1443 between licensed networks
• 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 60/005 Multiple registrations, e.g. multihoming
• CPC Class Codes: H04W 76/50 for emergency connections

Abstract

A mobile station that is initially attached to a first type of wireless access network is involved in a packet-switched emergency call. Upon detection of transitioning of the mobile station, a message is sent indicating transitioning of the mobile station from the first type wireless access network to the second type wireless access network to cause the packet-switched emergency call to be performed over the second type wireless access network.

Claims

1. A method comprising:

detecting, by one or more processors, that a mobile station is involved in a packet-switched emergency call, wherein the mobile station is initially attached to a first type of wireless access network;

detecting, by the one or more processors, transitioning of the mobile station from the first type wireless access network to a second, different type of wireless access network; and

in response to detecting transitioning of the mobile station, the one or more processors sending a message indicating transitioning of the mobile station from the first type wireless access network to the second type wireless access network to cause the packet-switched emergency call to be performed over the second type wireless access network after the transitioning.

2. The method of claim 1, wherein the one or more processors that perform the detecting tasks and the sending task are in the mobile station.

3. The method of claim 1, wherein the one or more processors that perform the detecting tasks and the sending task are part of a base station in the first type wireless access network.

4. The method of claim 1, further comprising:

pre-registering the mobile station with the second type wireless access network when the mobile station is initially attached to the first type wireless access network.

5. The method of claim 4, wherein pre-registering the mobile station includes establishing a session between the mobile station and the second type wireless access network.

6. The method of claim 4, wherein after the transitioning from the first type wireless access network to the second type wireless access network, the mobile station does not have to perform a registration procedure with the second type wireless access network to perform the packet-switched emergency call since the mobile station is already pre-registered with the second type wireless access network.

7. The method of claim 1, further comprising:

storing information relating to a predefined emergency call session to be used with the second type wireless access network.

8. The method of claim 7, further comprising:

after the handoff of the mobile station to the second type wireless access network, using the information of the predefined emergency call session to avoid having to negotiate a context of the packet-switched emergency call with the second type wireless access network.

9. The method of claim 1, further comprising:

as part of the handoff, including in one or more messages sent to the second type wireless access network an emergency indication.

10. The method of claim 1, wherein the first type wireless access network is an Evolved Universal Terrestrial Radio Access (EUTRA) network.

11. The method of claim 10, wherein the second type wireless access network is a High Rate Packet Data (HRPD) access network.

12. A communications node comprising:

one or more processors configured to;

store information regarding a session for a packet-switched emergency call, where in the session is between a mobile station and a target wireless access network;

communicate messaging to allow transitioning of the mobile station from a source wireless access network to the target wireless access network, wherein the source and target wireless access networks are different types of networks; and

after the transitioning, using the stored information to establish the packet-switched emergency call over the target wireless access network.

13. The communications node of claim 12, comprising the mobile station.

14. The communications node of claim 12, comprising a node in the target wireless access network.

15. The communications node of claim 12, wherein the information is stored in response to pre-registering the mobile station with the target wireless access network while the mobile station is attached to the source wireless access network.

16. The communications node of claim 12, wherein the stored information is related to a predefined emergency call session.

17. The communications node of claim 12, wherein the source wireless access network is an Evolved Universal Terrestrial Radio Access (EUTRA) network.

18. The communications node of claim 12, wherein the messaging comprises messaging according to a standard of the target wireless access network tunneled through a link between the mobile station and the source wireless access network.

19. An article comprising at least one computer-readable storage medium storing instructions that upon execution cause by one or more processors to:

detect that a mobile station is involved in a packet-switched emergency call, wherein the mobile station is initially attached to a first type of wireless access network;

detect transitioning of the mobile station from the first type wireless access network to a second, different type of wireless access network; and

in response to detecting transitioning of the mobile station, send a message indicating transitioning of the mobile station from the first type wireless access network to the second type wireless access network to cause the packet-switched emergency call to be performed over the second type wireless access network after the transitioning.

20. The article of claim 19, wherein the instructions upon execution cause the one or more processors to further perform one of:

pre-registering a session with the second type wireless access network while the mobile station is attached to the first type wireless access network; and

store information relating to a predefined emergency call session for use after transitioning of the mobile station to the second type wireless access network.

21. A method comprising:

storing information relating to a predefined emergency call session to be used between a mobile station and a wireless access network; and

establishing, by one or more processors, a packet-switched emergency call using the stored information relating to the predefined emergency call session.

22. The method of claim 21, wherein the one or more processors are part of the mobile station or part of a base station in the wireless access network.

23. A communications node comprising:

a computer-readable storage medium to store information relating to a predefined emergency call session to be used between a mobile station and a wireless access network; and

one or more processors configured to establish a packet-switched emergency call using the stored information relating to the predefined emergency call session.

24. The communications node of claim 23, comprising the mobile station or a base station in the wireless access network.