For a UE in NR-DC, either the MN or the SN can generate QoE configuration(s) and transmit the configuration to the UE. If both the MN and the SN send QoE configurations to the UE, the MN and the SN do not use the same set of application layer measurement configuration identities, which means there is a unique ID for QoE configurations across MN and SN. For a UE in NR-DC, the MN and the SN may coordinate QoE measurement collection activation and reporting as follows: For management-based QoE activation, the MN:

• Allocates the application layer measurement configuration ID for QoE measurement configurations to be configured at UEs served by the MN and the SN, and indicates it to the SN if needed;
• Determines whether the MN or the SN sends the QoE configuration to the UE, in case the SN inquires the MN.
• Can inform the SN that a UE is configured with a management-based QoE.

For management-based QoE measurement configurations received directly by the SN from OAM, the SN may perform UE selection. For a selected UE, the SN indicates to the MN the QoE reference of the management-based QoE configuration and, separately for the QoE reports and RAN visible QoE reports, the SN indicates whether it is going to receive the corresponding reports directly using SRB5 or via the MN (using SRB4). Upon receiving the coordination request, the MN can decide and notify the SN whether the MN sends the QoE and RAN Visible QoE configuration to the UE, or whether the SN should send the configuration(s) to the UE. The SN can send a QoE and/or a RAN Visible QoE measurement configuration directly to the UE via SRB3, or in a transparent container to the MN, which then sends the configuration to the UE via SRB1. For management-based QoE configurations received directly by the MN from the OAM and for signalling-based QoE configurations, the MN can only send the configuration to the UE via SRB1, and the UE can send the QoE reports via SRB4 or SRB5. The MN should inform the SN that the UE is configured with the management-based QoE/RAN visible QoE measurement configuration. When the MN has released the management-based QoE/RAN visible QoE measurement configuration, the MN should inform the SN. For a UE in NR-DC, both SRB4 and SRB5 can be configured simultaneously for QoE reporting. The network explicitly and separately indicates to the UE whether to send encapsulated QoE reports and RAN visible QoE reports via SRB4 or SRB5, per QoE reference. The SRB for QoE reporting can be changed during the QoE measurement session. The command for changing the SRB used for reporting may be sent to the UE by the node that configured that specific QoE configuration. The node that currently receives the QoE reports via the Uu interface can request from the peer node that the QoE reporting path is changed to the peer node per QoE reference. The change of QoE reporting path needs to be approved by both nodes serving the UE. If encapsulated QoE reports (sent in measReportAppLayerContainer) cannot be sent because the SRB configured for the such reporting is not available, the UE continues to store the reports until the SRB is available or until the QoE configuration is released. If the MN has configured the UE with QoE measurements, and if the UE is configured to send the QoE reports to the SN, then, if the MN decides that the SN forwards the reports directly to the MCE, the MN should indicate to the SN the QoE reference, the MCE IP address and the application layer measurement configuration ID. If the SN has configured the UE with QoE measurements, and if the UE is configured to send the QoE reports to the MN, then, if the SN decides that the MN forwards the reports directly to the MCE, the SN should indicate to the MN the QoE reference and the MCE IP address. QoE reports can be transferred between the MN and the SN via the RRC TRANSFER message. If the SN has released a QoE configuration of a UE, the SN should inform the MN. When SCG is deactivated, for QoE configurations configured to use SRB5 for QoE reporting, it is up to network implementation whether to reconfigure the reporting leg to SRB4, release the QoE configuration or pause the QoE reporting. For UL data arrival on SRB5 while the SCG is deactivated, the UE does not indicate to the MN that it has QoE report to transmit over SRB5 for the purpose of SCG activation. When the SCG is released, the UE releases all the QoE measurements configured by the SCG and discards the unsent QoE reports configured to be reported via SRB5. In order to allow the transmission of application layer measurement reports which exceed the maximum PDCP SDU size, the network can inform the UE whether the MN allows RRC segmentation of MeasurementReportAppLayer message via SRB4 and whether the SN allows RRC segmentation of MeasurementReportAppLayer message via SRB5.

In NR-DC, when RAN overload happens in the node which receives the QoE reports from the UE, the node may either determine to pause the QoE reporting from the UE as specified in TS 38.300 or the node may coordinate with its peer node to reconfigure the QoE reporting path and offload one or more of the QoE sessions, by sending the QoE Reporting Path Request in the QMC Coordination Request IE, via the MN-initiated and SN-initiated SN modification procedure. The peer node may approve the reconfiguration of the QoE reporting leg of the one or more QoE sessions, by sending the QoE Reporting Path Response in the QMC Coordination Response IE in the response message for SN modification. When the peer node is not able to accept the Reporting Path Request of one or more QoE sessions, the node that is overloaded in NR-DC may pause the QoE reporting from the UE for those QoE sessions as specified in TS 38.300. When neither the MN nor the SN is able to receive the QoE reports due to RAN overload, the network can indicate to the UE to pause QoE reporting, as specified in TS 38.300.

Either the MN or the SN can generate and send a RAN visible QoE configuration to the UE. The gNB that has initially configured a UE in NR-DC with a RAN visible QoE configuration can modify and release the RAN visible QoE configuration as long as the UE is connected to this gNB. The gNB that configures the encapsulated QoE measurements to UE is referred to as the RAN visible QoE-configuring gNB, and the peer node is referred to as the non-RAN visible QoE-configuring gNB. Upon mobility, the RAN visible QoE-configuring gNB may be changed. The UE may send RAN visible QoE reports to the network using either SRB4 or SRB5. In addition, the gNB that received a RAN visible QoE report can forward the report to the other gNB (the SN or the MN). QoE reports and RAN visible QoE reports pertaining to the same QoE Reference can be sent over the same SRB or they can be sent over different SRBs. If RAN visible QoE reports cannot be sent because the SRB configured for RAN visible QoE measurement reporting is not available, the UE discards the RAN visible QoE report. The RAN visible QoE-configuring gNB can configure RAN visible QoE measurements at a UE without a priori knowledge about which gNB(s) will provide the bearer(s) for a future application session. During the lifetime of an application session, to ensure that the RAN visible QoE reports are sent to the gNB(s) that provide the bearer(s) which carry the data flow(s) associated with the RAN visible QoE measurement result in a RAN visible QoE report, the gNB receiving the RAN visible QoE reports determines the bearer(s) used to deliver the application session data flow(s) and the associated gNB (s). The determination may be based on the PDU session ID(s) and the QoS flow ID(s) indicated in a received RAN visible QoE report. When the RAN visible QoE-configuring gNB receives a RAN visible QoE measurement report and determines that the non-RAN Visible QoE-configuring gNB provides at least one bearer for the application session, the RAN Visible QoE-configuring gNB indicates that to the non-RAN Visible QoE-configuring gNB. The non-RAN Visible QoE-configuring gNB can then, if needed, indicate to the RAN visible QoE-configuring gNB its preference with respect to the reporting path for the subsequent RAN visible QoE reports and its preferred RAN visible QoE configuration parameters. If a gNB receives a RAN visible QoE report from a UE in NR-DC, and determines that the bearer(s) for the application session data flow(s) is (are) also provided by the other gNB, or only, provided by the other gNB, the gNB that received the RAN visible QoE measurement report may forward the received RAN visible QoE report to the other gNB. The RAN visible QoE reports can be transferred between the MN and the SN via the RRC TRANSFER message. The RAN visible QoE configuration may also be modified or released.