Method and apparatus for supporting new service in wireless communication system

A user equipment (UE) in a wireless communication system, the UE comprising:

• a transceiver;
• at least one processor;
• and
• memory storing instructions that, when executed by the at least one processor, cause the UE to:
• receive, by the UE providing a first service including a voice over new radio (VoNR) in a first radio access technology (RAT), a request for a second service including an unstructured supplementary service data (USSD) or a short message service (SMS);
• identify at least one RAT capable of supporting the second service and a voice call service based on a database of the UE including service support information in case that the second service is unable to be performed on the first RAT;
• perform handover to a second RAT among the at least one RAT;
• and
• perform the second service in the second RAT,
• wherein the first RAT is a fifth generation (5G) standalone (SA) network or a 3rd generation partnership project (3GPP) access network, and
• wherein the second RAT providing the voice call service is either a third generation (3G) network, a fourth generation (4G) network, or a non-3GPP access network,
• wherein the service support information for at least one RAT includes priority information and at least one of a mobile country code (MCC), a mobile network code (MNC), a service name, or a domain including a network access server (NAS) and an over-Internet protocol (IP),
• wherein the second RAT among the at least one RAT is determined based on the priority information, and
• wherein the priority information is based on at least one of information preconfigured in the UE or information of at least one RAT previously connected to the first RAT.