Method for performing location registration by remote UE in wireless communication system, and apparatus therefor

1. A method of performing location registration by a remote user equipment (UE) in a wireless communication system, the method comprising:

transmitting a direct communication request message to a relay UE;

receiving, from the relay UE, a direct communication response message including location registration period information and location registration action time information in response to the direct communication request message; and

transmitting a first tracking area update (TAU) request message to a mobility management entity (MME), upon expiration of the location registration action time information,

wherein the location registration period information is applied after the location registration action time information is applied, and

wherein, after transmitting the first TAU request message, the remote UE transmits a second TAU request message after expiration of a time corresponding to the location registration period information.

2. The method according to claim 1 , wherein the location registration period information is a time period starting from the expiration of the location registration action time information.

3. The method according to claim 1 , wherein the location registration action time information corresponds to a time from transmission of the direct communication response message to initiation of a TAU procedure at the relay UE.

4. The method according to claim 1 , wherein the first TAU request message includes the location registration period information.

5. The method according to claim 4 , wherein the location registration period information included in the first TAU request message is a period configuration request for the MME receiving the first TAU request message.

6. The method according to claim 5 , wherein the MME of the remote UE is different from an MME of the relay UE.

7. The method according to claim 1 , wherein the first TAU request message is transmitted through the relay UE.

8. The method according to claim 1 , wherein if the MME of the remote UE is identical to an MME of the relay UE, the remote UE receives emergency call-related information from the relay UE.

9. The method according to claim 1 , wherein the remote UE receives, from the MME, a TAU response message including emergency call-related information in response to the transmitted TAU request message.

10. The method according to claim 1 , wherein if the emergency call-related information indicates that IP multimedia subsystem (IMS) emergency call is not supported, the remote UE performs radio access technology (RAT) switching.

11. The method according to claim 10 , wherein the remote UE makes an emergency call in a switched RAT after the RAT switching.

12. A remote user equipment (UE) for performing location registration in a wireless communication system, the remote UE comprising:

a transceiver; and

a processor operatively connected to the transceiver,

wherein the processor is configured to:

control the transceiver to transmit a direct communication request message to a relay UE,

control the transceiver to receive, from the relay UE through the transceiver, a direct communication response message including location registration period information and location registration action time information in response to the direct communication request message, and

upon expiration of the location registration action time information, control the transceiver to transmit a first tracking area update (TAU) request message to a mobility management entity (MME),

wherein the location registration period information is applied after the location registration action time information is applied, and

wherein, after transmitting the first TAU request message, the remote UE transmits a second TAU request message after expiration of a time corresponding to the location registration period information.

13. The remote UE according to claim 12 , wherein the location registration period information is a time period starting from the expiration of the location registration action time information.