Method and apparatus for serving quality of service (QOS) flow in a wireless communication system
A method and apparatus are disclosed from the perspective of a network node. In one embodiment, the method includes the network node transmitting a first message with a DRB (Data Radio Bearer) configuration to a UE (User Equipment) for establishing a default DRB for a PDU (Packet Data Unit) session, wherein the DRB configuration includes a QFI (QoS Flow Id) configuration used to indicate whether a QFI field is present or not in uplink for the default DRB and the QFI configuration is always set to a value indicating the QFI field is present in uplink for the default DRB. The method further includes the network node establishing the default DRB with a presence of the QFI field in uplink. The method also includes the network node receiving a SDAP (Service Data Adaptation Protocol) PDU with the QFI field via the default DRB from the UE.
1. A method of a network node, comprising:
transmitting a first RRC (Radio Resource Control) message with a DRB (Data Radio Bearer) configuration to a UE (User Equipment) for establishing a default DRB for a PDU (Protocol Data Unit) session, wherein the DRB configuration includes a QFI (QoS Flow Id) configuration used to indicate whether a QFI field is present or not in uplink for the default DRB and the QFI configuration is always set to a value indicating the QFI field is present in uplink for the default DRB;
establishing the default DRB with a presence of the QFI field in uplink; and
receiving a SDAP (Service Data Adaptation Protocol) PDU with the QFI field via the default DRB from the UE.
2. The method of claim 1 , wherein the network node is not allowed to transmit a second RRC message to the UE for reconfiguring the QFI configuration for the default DRB to no presence of the QFI field.
3. The method of claim 1 , wherein a header in the SDAP PDU includes at least the QFI field.
4. The method of claim 1 , wherein the network node transmits an IP (Internet Protocol) packet included in the SDAP PDU to a core network.
5. The method of claim 1 , wherein the network node is a base station (or gNB).
6. A network node, comprising:
a control circuit;
a processor installed in the control circuit; and
a memory installed in the control circuit and operatively coupled to the processor;
wherein the processor is configured to execute a program code stored in the memory to:
transmit a first RRC (Radio Resource Control) message with a DRB (Data Radio Bearer) configuration to a UE (User Equipment) for establishing a default DRB for a PDU (Protocol Data Unit) session, wherein the DRB configuration includes a QFI (QoS Flow Id) configuration used to indicate whether a QFI field is present or not in uplink for the default DRB and the QFI configuration is always set to a value indicating the QFI field is present in uplink for the default DRB;
establish the default DRB with a presence of the QFI field in uplink; and
receive a SDAP (Service Data Adaptation Protocol) PDU with the QFI field via the default DRB from the UE.
7. The network node of claim 6 , wherein the network node is not allowed to transmit a second RRC message to the UE for reconfiguring the QFI configuration for the default DRB to no presence of the QFI field.
8. The network node of claim 6 , wherein a header in the SDAP PDU includes at least the QFI field.
9. The network node of claim 6 , wherein the network node transmits an IP (Internet Protocol) packet included in the SDAP PDU to a core network.
10. The network node of claim 6 , wherein the network node is a base station (or gNB).