Section: 13.4.3.1 QoE Measurement Collection Activation and Reporting in NR-DC
Content: 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, 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. 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 session and, separately for the QoE reports and RAN visible QoE reports, the SN indicates whether it is going to receive the corresponding reports via the MN (using SRB4) or using SRB5. Upon receiving the 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 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 from 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. For a UE in NR-DC, both SRB4 and SRB5 can be configured simultaneously for QoE reporting. The network explicitly indicates to the UE whether to send QoE reports via SRB4 or SRB5, per QoE reference, separately for QoE reports and RAN visible QoE reports. The SRB for QoE reporting can be changed during the application 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 leg is switched to the peer node per QoE Reference. The leg switch for QoE reporting needs to be approved by both nodes serving the UE. RAN visible QoE reports can be sent via the same SRB as the QoE reports pertaining to the same QoE reference, or via a different SRB. RAN visible QoE reports can be sent to the SN directly via SRB5, or via the MN using SRB4. If encapsulated QoE reports cannot be sent because the SRB configured for the encapsulated QoE reporting is not available, the UE continues to store the reports until the SRB is available or the QoE configuration is released. 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 MN should inform the SN that a UE is configured with a management-based QoE/RAN visible QoE measurement configuration. 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. If the SN has released a QoE configuration towards 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 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.