Method for performing a procedure related to AMF registration by UDM in wireless communication system and apparatus for same

1. A method for enabling a UDM (Unified Data Management) to perform a registration related procedure of an AMF (Access and Mobility Management Function) in a wireless communication system, the method comprising:

receiving, by the UDM, a first message related to serving AMF registration of a UE, which includes (i) access type information indicating one of 3GPP access and non-3GPP access and (ii) AMF ID (Identity) information, from a first AMF;

transmitting, by the UDM, a second message for deregistration of a second AMF registered as a serving AMF of the UE,

wherein the second message is only transmitted in a first case among a first case and a second case,

wherein the first case means an access type of the first AMF is 3GPP access and an access type of the second AMF is 3GPP access,

wherein the second case means an access type of the first AMF is non-3GPP access and an access type of the second AMF is 3GPP access.

2. The method according to claim 1 , further comprising:

storing, by the UDM, the access type information related to the AMF and the AMF ID information,

wherein the access type information and the AMF ID information are related to the first AMF.

3. The method according to claim 1 , further comprising:

receiving, by the UDM, a third message related to deletion of UE context from a Network Function (NF) that corresponds to AMF, wherein the third message includes access type information.

4. The method according to claim 1 , wherein, based on the UDM transmitting a deregistration related message to the second AMF due to subscription withdrawn, the UDM indicates an access type of the deregistration related message.

5. The method according to claim 1 , further comprising:

transmitting, by the UDM to the NF, serving AMF information corresponding to the access type, based on a fourth message for requesting the serving AMF information being received from the NF, and wherein the fourth message includes access type information.

6. The method according to claim 1 , further comprising:

receiving, by the UDM, a request for providing UE reachability information from the NF, wherein the request for requesting to provide UE reachability information includes access type information.

7. The method according to claim 1 , wherein, based on a handover from a 5GS (5G system) to an EPS (Evolved Packet System), cancel location operation by the UDM and HSS (Home Subscriber Server) is performed for AMF of which access type is 3GPP.

8. The method according to claim 1 , wherein, based on changes from a 5GS to an EPS of UE in an idle mode, a cancel location operation by the UDM is performed for AMF of which access type is 3GPP.

9. A UDM (Unified Data Management) device configured to perform a registration related procedure of an AMF (Access and Mobility Management Function) in a wireless communication system, the UDM comprising:

a memory; and

a processor coupled with the memory,

wherein the processor is configured to receive a first message related to serving AMF registration of a UE, wherein the first message includes (i) access type information indicating one of 3GPP access and non-3GPP access and (ii) AMF ID (Identity) information, from a first AMF, and transmit a second message for deregistration of a second AMF registered as a serving AMF of the UE,

wherein the second message is only transmitted in a first case among a first case and a second case,

wherein the first case means an access type of the first AMF is 3GPP access and an access type of the second AMF is 3GPP access,

wherein the second case means an access type of the first AMF is non-3GPP access and an access type of the second AMF is 3GPP access.

10. The UDM device according to claim 9 , wherein the processor is further configured to store the access type information related to the AMF and the AMF ID information,

wherein the access type information and the AMF ID information are related to the first AMF, and.

11. The UDM device according to claim 9 , wherein the processor is further configured to receive a third message related to deletion of UE context from a Network Function (NF) that corresponds to AMF, and the third message includes access type information.

12. The UDM device according to claim 9 , wherein, based on the UDM transmitting a deregistration related message to the second AMF due to subscription withdrawn, the UDM indicates an access type of the deregistration related message.

13. The UDM device according to claim 9 , wherein the processor is further configured to transmit serving AMF information corresponding to the access type to the NF, and the fourth message includes access type information, based on a fourth message for requesting the serving AMF information being received from the NF.