Method and apparatus for supporting inter-system mobility in wireless communication systems

A communication method performed by a user equipment receiving network slice identification information, the communication method comprising:

• transmitting, to a Mobility Management Entity (MME), a Packet Data Network (PDN) connection request message including information about a certain Access Point Name (APN);
• receiving, as a response to the connection request message, a response message including at least one piece of network slice information corresponding to the APN;
• and
• storing the at least one piece of network slice information of the response message,
• wherein the at least one piece of network slice information is used when the user equipment moves to a 5G system (5GS).

A first entity supporting inter-system mobility, the first entity comprising:

• a transceiver;
• and
• a processor coupled to the transceiver and configured to receive a create session request message including information about an Access Point Name (APN), for which a user equipment requests a packet data network (PDN) connection, subscriber identification information of the user equipment, and a field indicating capability information of the user equipment about slice identification information,
• determine, based on the create session request message, whether movement to a 5G system (5GS) is required for the PDN connection,
• transmit, based on a result of the determining, to a second entity, a subscriber information request including the subscriber identification information and the APN information,
• receive, from the second entity, a response to the subscriber information request including identification information of one or more subscribed network slices corresponding to the subscriber identification information, and
• provide, to the user equipment, at least one piece of the identification information of the one or more subscribed network slices.

A user equipment configured to receive network slice identification information, the user equipment comprising:

• a transceiver;
• and
• a processor coupled to the transceiver and configured to transmit, to a Mobility Management Entity (MME), a Packet Data Network (PDN) connection request message including information about a certain Access Point Name (APN),
• receive, as a response to the connection request message, a response message including at least one piece of network slice information corresponding to the APN, and
• store the at least one piece of network slice information of the response message,
• wherein the at least one piece of network slice information is used when the user equipment moves to a 5G system (5GS).