METHOD FOR PROCESSING EMERGENCY CALL IN WIRELESS COMMUNICATION SYSTEM AND APPARATUS FOR SUPPORTING SAME

• US 20160119959A1
• Filed: 05/09/2014
• Published: 04/28/2016
• Est. Priority Date: 05/09/2013
• Status: Active Grant

• Current Assignee: LG Electronics, Inc. (LG Corporation)
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: JUNG, Sunghoon, LEE, Youngdae, PARK, Sungjun, YI, Seungjune, LEE, Jaewook
• Granted Patent: US 9,655,148 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H04W 24/04 Arrangements for maintaining operational condition
• CPC Class Codes: H04W 48/20 Selecting an access point
• CPC Class Codes: H04W 76/19 Connection re-establishment
• CPC Class Codes: H04W 76/27 Transitions between radio resource control [RRC] states
• CPC Class Codes: H04W 76/50 for emergency connections

Abstract

Provided are a method by which a terminal processes an emergency call in a wireless communication system, and an apparatus for supporting the same. The method comprises: selecting a cell when a radio link failure (RLF) is generated; transmitting a RRC connection re-establishment request message to the selected cell; stopping an expired timer if a suitable cell or a cell using different radio access technology (RAT) is not selected within a certain time when the RLF is generated in the emergency call process of the terminal and the selected cell is an acceptable cell; and transmitting the RRC connection reestablishment request message.

Claims

1. A method by which a user equipment processes an emergency call in a wireless communication system, the method comprising:

selecting a cell when a radio link failure (RLF) occurs; and

transmitting a radio resource control (RRC) connection re-establishment request message to the selected cell,

wherein if the RLF occurs in the emergency call process of the user equipment and if the selected cell is an acceptable cell, a timer which expires when a suitable cell or a cell using another radio access technology (RAT) is not selected within a certain time stops, and the RRC connection re-establishment request message is transmitted.

2. The method of claim 1, wherein if the timer expires, the user equipment transitions to an RRC-idle state.

3. The method of claim 1, further comprising:

receiving an RRC connection re-establishment message; and

transmitting an RRC connection re-establishment complete message.

4. The method of claim 1, wherein if the RLF occurs in a non-emergency process and if the selected cell is the acceptable cell, transmitting the RRC connection re-establishment request message after the timer expires.

5. The method of claim 4, further comprising:

receiving the RRC connection re-establishment message; and

transmitting an RRC connection re-establishment complete message.

6. The method of claim 1, wherein if the RLF occurs in a non-emergency call process and if the selected cell is the acceptable cell, transmitting the RRC connection re-establishment request message before the timer expires.

7. The method of claim 6, further comprising:

receiving the RRC connection re-establishment message; and

transmitting an RRC connection re-establishment complete message.

8. A wireless device comprising:

a radio frequency (RF) unit for transmitting and receiving a radio signal; and

a processor operatively coupled to the RF unit,

wherein the processor is configured for;

selecting a cell when a radio link failure (RLF) occurs; and

transmitting a radio resource control (RRC) connection re-establishment request message to the selected cell,

wherein if the RLF occurs in the emergency call process of the user equipment and if the selected cell is an acceptable cell, a timer which expires when a suitable cell or a cell using another radio access technology (RAT) is not selected within a certain time stops, and the RRC connection re-establishment request message is transmitted.

9. The wireless device of claim 8, wherein if the timer expires, the processor transitions to an RRC-idle state.

10. The wireless device of claim 8, wherein the processor is further configured for:

receiving an RRC connection re-establishment message; and

transmitting an RRC connection re-establishment complete message.

11. The wireless device of claim 8, wherein if the RLF occurs in a non-emergency call process and if the selected cell is the acceptable cell, the RRC connection re-establishment request message is transmitted after the timer expires.

12. The wireless device of claim 11, wherein the processor is further configured for:

receiving the RRC connection re-establishment message; and

transmitting an RRC connection re-establishment complete message.

13. The wireless device of claim 8, wherein if the RLF occurs in a non-emergency call process and if the selected cell is the acceptable cell, the RRC connection re-establishment request message is transmitted before the timer expires.

14. The wireless device of claim 13, wherein the processor is further configured for:

receiving the RRC connection re-establishment message; and

transmitting an RRC connection re-establishment complete message.