Handling session management procedure outside of network slice supported area or time

A method performed by a network apparatus for handling session management (SM) procedures in a wireless network system, the method comprising:

• establishing a protocol data unit (PDU) session with a user equipment (UE) in the wireless network system;
• receiving one of a PDU session release request message or a PDU session modification request message from the UE, in case that the UE is in a tracking area (TA) where a single-network slice selection assistance information (S-NSSAI) associated with the PDU session is not allowed or not supported by the network apparatus;
• and
• performing one of:
• releasing the PDU session associated with the UE when the PDU session release request message is received from the UE, and transmitting a PDU session release response message to the UE after releasing the PDU session, or
• modifying the PDU session associated with the UE when the PDU session modification request message is received from the UE, and transmitting a PDU session modification response message to the UE after modifying the PDU session.

A user equipment (UE) for handling session management (SM) procedures in a wireless network system, the UE comprising:

• a transceiver;
• and
• memory, comprising one or more storage media, storing instructions;
• and
• one or more processors communicatively coupled to the transceiver and the memory,
• wherein the instructions, when executed by the one or more processors individually or collectively, cause the UE to:
• establish a protocol data unit (PDU) session with a network apparatus in the wireless network system,
• determine whether the UE is in a tracking area (TA) where a single-network slice selection assistance information (S-NSSAI) associated with the PDU session is not allowed or not supported by the network apparatus, and
• in case that the UE is in the TA where the S-NSSAI of the PDU session is not allowed or not supported by the network apparatus, initiate a PDU session release procedure or initiate a PDU session modification procedure.

A network apparatus for handling session management (SM) procedures in a wireless network system, the network apparatus comprising:

• a transceiver;
• and
• memory, comprising one or more storage media, storing instructions;
• and
• one or more processors communicatively coupled to the transceiver and the memory,
• wherein the instructions, when executed by the one or more processors individually or collectively, cause the network apparatus to:
• establish a protocol data unit (PDU) session with a user equipment (UE) in the wireless network system,
• receive one of a PDU session release request message or a PDU session modification request message from the UE, in case that the UE is in a tracking area (TA) where a single-network slice selection assistance information (S-NSSAI) associated with the PDU session is not allowed or not supported by the network apparatus, and
• perform one of:
• release the PDU session associated with the UE when the PDU session release request message is received from the UE, and transmit a PDU session release response message to the UE after releasing the PDU session, or
• modify the PDU session associated with the UE when the PDU session modification request message is received from the UE, and transmit a PDU session modification response message to the UE after modifying the PDU session.