21.4 RAN Visible QoE Measurements

RAN visible QoE measurements are configured at the UE by the gNB, where a subset of configured QoE metrics is reported from the UE to the gNB as an explicit IE readable by the gNB. The RAN visible QoE measurements can be used by the gNB for network optimization. The RAN visible QoE measurements are supported for the DASH streaming and VR services. The gNB configures the RAN visible QoE measurement of all or some of the available RAN visible QoE metrics, where the indication of metric availability is received by the gNB as part of the management-based or the signalling-based QoE configuration. The set of available RAN visible QoE metrics is a subset of the metrics configured as part of QoE measurement configuration encapsulated in the application layer measurement configuration container. RAN visible QoE measurements and encapsulated QoE measurements can be configured together or separately. RAN visible QoE measurements can only be configured if there is a corresponding QoE measurement configuration for the same service type configured at the UE. The gNB may modify a RAN visible QoE configuration by releasing it and configuring the UE with a new RAN visible QoE configuration pertaining to the same QoE reference. In this case, the new RAN visible QoE configuration applies immediately, i.e., even during the same application session.

Multiple simultaneous RAN visible QoE measurement configurations and reports can be supported for RAN visible QoE measurements, and each RAN visible QoE measurement configuration and report is identified by the same measurement configuration application layer ID as the corresponding QoE measurement configuration and measurement report. After receiving the RAN visible QoE measurement configuration, the UE AS layer forwards the configuration to the application layer, indicating the service type, the measurement configuration application layer ID and, optionally, the reporting periodicity for RAN visible QoE. The application layer sends the RAN visible QoE measurement report associated with the measurement configuration application layer ID to the UE's AS layer. The PDU session ID(s) and QoS Flow ID(s) per PDU session ID corresponding to the service that is subject to QoE measurements can also be reported by the UE along with the RAN visible QoE measurement results.

The RAN visible QoE measurements can be reported with a reporting periodicity different from the one of the corresponding encapsulated QoE measurements, when a dedicated RAN visible QoE reporting periodicity is configured by the gNB. The UE application layer can measure the RAN visible QoE metrics based on this reporting periodicity. If there is no reporting periodicity defined in the RAN visible QoE configuration, the UE sends both RAN visible QoE measurement reports and the QoE measurement reports to the gNB in the same MeasurementReportAppLayer message, except when QoE measurement reporting pause indication is received (e.g., in case of RAN overload). When a QoE measurement reporting is paused, if there is no reporting periodicity defined in the RAN visible QoE configuration, the encapsulated QoE reports are stored at the UE's AS layer, but the RAN visible QoE reports continue to be reported to the gNB with the reporting periodicity configured for encapsulated QoE reporting.

The gNB can release one or multiple RAN visible QoE measurement configurations from the UE in one RRCReconfiguration message at any time. If the encapsulated QoE configuration is released, the corresponding RAN visible QoE configuration is released as well.

The RAN visible QoE configuration can be transferred from the source gNB to the target gNB upon mobility and from the old gNB to the new gNB during context retrieval. The target gNB or the new gNB can generate a new RAN visible QoE configuration based on the available RAN visible QoE metrics received and it can send the new RAN visible QoE configuration to the UE during handover or the RRC resume procedure.