Session management in wireless communication system

A method, comprising:

• receiving a protocol data unit (PDU) session modification command message from a core network requesting a flow description operation at a user equipment (UE) during a PDU session modification procedure;
• when the flow description operation is create a new Quality of Service (QoS) flow description, or modify existing QoS flow description, determining there is an invalid QoS flow description of a guaranteed bit rate (GBR) QoS flow upon determining that the QoS flow description of the GBR QoS flow lacks at least one of mandatory parameters;
• and
• upon determining that there is the invalid QoS flow description of the GBR QoS flow which lacks at least one of the mandatory parameters, performing an error handling operation to handle the invalid QoS flow description,
• wherein the error handling operation includes:
• when there is no default QoS rule associated with the QoS flow description of the GBR QoS flow which lacks at least one of the mandatory parameters, if a QoS rules Information Element (IE) of the PDU session modification command message contains at least one valid QoS rule, or a QoS flow description IE of the PDU session modification command message contains at least one other valid QoS flow description, further processing one or more requests corresponding to the at least one valid QoS rule, or the at least one other valid QoS flow description without diagnose an error to trigger a reject to the PDU session modification command message,
• completing the PDU session modification procedure,
• deleting the QoS flow description which lacks at least one of the mandatory parameters and one or more QoS rules, if any, associated with the QoS flow description which lacks at least one of the mandatory parameters, and
• initiating a UE requested PDU session modification procedure by sending a PDU session modification request message with a 5G session management (5GSM) cause #84 syntactical error in the QoS operation to delete the QoS flow description which lacks at least one of the mandatory parameters and one or more QoS rules, if any, associated with the QoS flow description which lacks at least one of the mandatory parameters.

A method, comprising:

• receiving a protocol data unit (PDU) session establishment accept message from a core network requesting a flow description operation at a user equipment (UE) during a PDU session establishment procedure requested by the UE;
• when the flow description operation is create a new Quality of Service (QoS) flow description, determining there is an invalid QoS flow description of a guaranteed bit rate (GBR) QoS flow upon determining that the QoS flow description of the GBR QoS flow lacks at least one of mandatory parameters;
• and
• upon determining that there is the QoS flow description of the GBR QoS flow which lacks at least one of the mandatory parameters, performing an error handling operation to handle the invalid QoS flow description,
• wherein the error handling operation includes:
• when a default QoS rule of the PDU session is associated with the QoS flow description of the GBR QoS flow which lacks at least one of the mandatory parameters, initiating a PDU session release procedure by sending a PDU session release request message with a 5G session management (5GSM) cause #84 syntactical error in the QoS operation,
• when there is no default QoS rule associated with the QoS flow description of the GBR QoS flow which lacks at least one of the mandatory parameters, initiating a UE requested PDU session modification procedure by sending a PDU session modification request message with the 5G session management (5GSM) cause #84 syntactical error in the QoS operation to delete the QoS flow description which lacks at least one of the mandatory parameters and one or more QoS rules, if any, associated with the QoS flow description which lacks at least one of the mandatory parameters.