EMERGENCY CALLS FOR INTERNET PROTOCOL MULTIMEDIA SUBSYSTEM (IMS) OVER PACKET SWITCHED CODE DIVISION MULTIPLE ACCESS (CDMA) NETWORKS

• US 20110076982A1
• Filed: 09/30/2009
• Published: 03/31/2011
• Est. Priority Date: 09/30/2009
• Status: Active Grant

• Current Assignee: Verizon Patent and Licensing Incorporated (Verizon Communications Inc.)
• Original Assignee: Verizon Patent and Licensing Incorporated (Verizon Communications Inc.)
• Inventors: LI, Mingxing S., Ritter, Phillip A.
• Granted Patent: US 8,315,589 B2
• Time in Patent Office: Days
• US Class Current: 455/404.1
• CPC Class Codes: H04L 65/1016 IP multimedia subsystem [IMS]
• CPC Class Codes: H04M 2242/04 for emergency applications
• CPC Class Codes: H04W 36/0022 for transferring data sessions between adjacent core network technologies
• 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 4/90 Services for handling of emergency or hazardous situations, e.g. earthquake and tsunami warning systems [ETWS]
• CPC Class Codes: H04W 48/18 Selecting a network or a communication service
• CPC Class Codes: H04W 76/50 for emergency connections

Abstract

A mobile communication device receives initiation of an emergency call by a user of the mobile communication device, and determines whether a single-carrier radio transmission technology (1xRTT) network is available for the emergency call. The mobile communication device also routes the emergency call over the 1xRTT network when the 1xRTT network is available for the emergency call, and routes the emergency call over an enhanced high rate packet data (eHRPD) network when the 1xRTT network is unavailable for the emergency call.

Claims

1. A mobile communication device-implemented method, comprising:

receiving, by the mobile communication device, initiation of an emergency call by a user of the mobile communication device;

determining, by the mobile communication device, whether a single-carrier radio transmission technology (1xRTT) network is available for the emergency call;

routing, by the mobile communication device, the emergency call over the 1xRTT network when the 1xRTT network is available for the emergency call; and

routing, by the mobile communication device, the emergency call over an enhanced high rate packet data (eHRPD) network when the 1xRTT network is unavailable for the emergency call.

2. The mobile communication device-implemented method of claim 1, where the mobile communication device is dual registered in the 1xRTT network and the eHRPD network.

3. The mobile communication device-implemented method of claim 1, where routing the emergency call over the eHRPD network comprises:

routing the emergency call over the eHRPD network and an Internet protocol multimedia subsystem (IMS) network.

4. The mobile communication device-implemented method of claim 1, further comprising:

determining whether the mobile communication device is dual registered in the 1xRTT network and the eHRPD network;

determining whether the mobile communication device is registered in an Internet protocol multimedia subsystem (IMS) network; and

using a legacy emergency call routing method to route the emergency call when the mobile communication device is not registered in the eHRPD network and the IMS network.

5. The mobile communication device-implemented method of claim 1, where, when the 1xRTT network is available for the emergency call, the method further comprises:

determining whether the emergency call can be connected over the 1xRTT network;

connecting the emergency call to a public safety answering point (PSAP), via the 1xRTT network, when the emergency call can be connected over the 1xRTT network; and

routing the emergency call over the eHRPD network when the emergency call can not be connected over the 1xRTT network.

6. The mobile communication device-implemented method of claim 5, further comprising:

providing a domain notification message, over the 1xRTT network, indicating that the mobile communication device is attached to the 1xRTT network.

7. The mobile communication device-implemented method of claim 5, further comprising:

ending the emergency call over the 1xRTT network;

starting an emergency callback mode timer after the emergency call ends; and

remaining in an emergency callback mode for a time period, defined by the emergency callback mode timer, after the end of the emergency call over the 1xRTT network.

8. The mobile communication device-implemented method of claim 7, further comprising:

returning to a non-emergency operating mode when the emergency callback mode timer expires or when the user initiates an exit from the emergency callback mode; and

resuming connection with the eHRPD network and performing a registration with an Internet protocol multimedia subsystem (IMS) network.

9. The mobile communication device-implemented method of claim 1, where, when the 1xRTT network is unavailable for the emergency call, the method further comprises:

connecting the emergency call to a public safety answering point (PSAP), via the eHRPD network and an Internet protocol multimedia subsystem (IMS) network.

10. The mobile communication device-implemented method of claim 9, further comprising:

ending the emergency call over the eHRPD network;

starting an emergency callback mode timer after the emergency call ends; and

remaining in an emergency callback mode for a time period, defined by the emergency callback mode timer, after the end of the emergency call over the eHRPD network.

11. The mobile communication device-implemented method of claim 10, further comprising:

returning to a non-emergency operating mode when the emergency callback mode timer expires or when the user initiates an exit from the emergency callback mode; and

searching for the 1xRTT network.

12. The mobile communication device-implemented method of claim 1, where the mobile communication comprises one or more of:

a radiotelephone,

a personal communications system (PCS) terminal,

a wireless telephone,

a cellular telephone,

a smart phone,

a personal digital assistant (PDA), or

a laptop computer with a broadband air card.

13. A mobile communication device, comprising:

a memory to store a plurality of instructions; and

a processor to execute instructions in the memory to;

receiving initiation of an emergency call by a user of the mobile communication device, where the mobile communication device is dual registered in the circuit switched CDMA network and the packet switched CDMA network,

determine whether a circuit switched code division multiple access (CDMA) network is available for the emergency call,

route the emergency call over the circuit switched CDMA network when the circuit switched CDMA network is available for the emergency call, and

route the emergency call over a packet switched CDMA network when the circuit switched CDMA network is unavailable for the emergency call.

14. The mobile communication device of claim 13, where, when routing the emergency call over the packet switched CDMA network, the processor is further to:

route the emergency call over the packet switched CDMA network and an Internet protocol multimedia subsystem (IMS) network.

15. The mobile communication device of claim 13, where the processor is further to:

determine whether the mobile communication device is dual registered in the circuit switched CDMA network and the packet switched CDMA network, and

use a legacy emergency call routing method to route the emergency call when the mobile communication device is not registered in the packet switched CDMA network.

16. The mobile communication device of claim 13, where, when the circuit switched CDMA network is available for the emergency call, the processor is further to:

determine whether the emergency call is connected over the circuit switched CDMA network,

connect the emergency call to a public safety answering point (PSAP), via the circuit switched CDMA network, when the emergency call is connected over the circuit switched CDMA network, and

route the emergency call over the packet switched CDMA network when the emergency call is not connected over the circuit switched CDMA network.

17. The mobile communication device of claim 16, where the processor is further to:

provide a domain notification short message service (SMS) message, over the circuit switched CDMA network, indicating that the mobile communication device is attached to the circuit switched CDMA network.

18. The mobile communication device of claim 16, where the processor is further to:

complete the emergency call over the circuit switched CDMA network,

start an emergency callback mode timer after completion of the emergency call, and

remain in an emergency callback mode for a time period, defined by the emergency callback mode timer, after completion of the end of the emergency call over the circuit switched CDMA network.

19. The mobile communication device of claim 18, where the processor is further to:

return to a non-emergency operating mode when the emergency callback mode timer expires or when the user initiates an exit from the emergency callback mode.

20. The mobile communication device of claim 13, where, when the circuit switched CDMA network is unavailable for the emergency call, the processor is further to:

connect the emergency call to a public safety answering point (PSAP), via the packet switched CDMA network and an Internet protocol multimedia subsystem (IMS) network.

21. The mobile communication device of claim 20, where the processor is further to:

complete the emergency call over the packet switched CDMA network,

start an emergency callback mode timer after completion of the emergency call, and

remain in an emergency callback mode for a time period, defined by the emergency callback mode timer, after completion of the emergency call over the packet switched CDMA network.

22. The mobile communication device of claim 21, where the processor is further to:

return to a non-emergency operating mode when the emergency callback mode timer expires or when the user initiates an exit from the emergency callback mode.

23. The mobile communication device of claim 13, where the circuit switched CDMA network comprises one or more of:

a base station,

a radio network controller,

a mobile switching center (MSC),

a home location register (HLR), and

a positioning determination entity (PDE)

24. The mobile communication device of claim 13, where the packet switched CDMA network comprises one or more of:

a base station,

a high rate packet data serving gateway (HSGW),

packet data network gateway (PDN-GW),

a policy and charging rule function (PCRF), and

a home subscriber server front end (HSS-FE).

25. A mobile communication device comprising:

means for receiving initiation of an emergency call by a user of the mobile communication device;

means for determining whether a single-carrier radio transmission technology (1xRTT) network is available for the emergency call;

means for routing the emergency call over the 1xRTT network when the 1xRTT network is available for the emergency call;

means for routing the emergency call over an enhanced high rate packet data (eHRPD) network when the 1xRTT network is unavailable for the emergency call;

means for determining whether the mobile communication device is dual registered in the 1xRTT network and the eHRPD network;

means for determining whether the mobile communication device is registered in an Internet protocol multimedia subsystem (IMS) network; and

means for using a legacy emergency call routing method to route the emergency call when the mobile communication device is not registered in the eHRPD network or the IMS network.