The QoE Measurement Collection function enables collection of application layer measurements from the UE. QoE measurement collection is supported for the following service types in NR cells:

• QoE Measurement Collection for DASH streaming services;
• QoE Measurement Collection for MTSI services;
• QoE Measurement Collection for VR services.

The QoE Measurement Collection function also supports collection of QoE measurements for any of the supported service types carried by the MBS communication service. The QoE Measurement Collection is supported for the following two communication service types:

• MBS broadcast;
• MBS multicast.

For DASH streaming, MTSI and VR, QMC is supported in RRC_CONNECTED state only, unless the application data is delivered via the MBS broadcast communication service. For application sessions delivered via MBS broadcast, QMC is supported in RRC_CONNECTED, RRC_INACTIVE, and RRC_IDLE states. QMC for the application sessions delivered via MBS multicast is supported in RRC_CONNECTED state only. Both signalling based and management based QoE measurement collection are supported in NR SA and NR-DC. Further details of NR-DC operation can be found in TS 37.340.

QoE measurement collection continuity for intra-system intra-RAT/inter-RAT handover is supported, with the Area Scope parameters configured by the OAM, where the network is responsible for keeping track of whether the UE is inside or outside the area scope. A UE continues an ongoing QoE measurement even if it leaves the area scope, unless the network indicates to the UE to release the application layer measurement configuration. For handover, the source gNB may transmit the information related to one or more application layer measurement configurations of the UE to the target gNB via XnAP or NGAP. For signalling-based QoE, the service type indication, the QoE reference, and, optionally, the container for application layer measurement configuration, MCE IP address, measurement configuration application layer ID, MDT alignment information, area scope, slice support list for QMC, available RAN visible QoE metrics, QoE measurement session status, MBS communication service type, and assistance information for QoE measurement are passed to the target gNB. For management-based QoE, the QoE reference, service type indication, and, optionally, the measurement configuration application layer ID, the MCE IP address, area scope, slice support list for QMC, MBS communication service type, assistance information for QoE measurement and QoE measurement session status are passed to the target gNB. For RRC_INACTIVE state mobility, QoE measurement configuration(s) of a specific UE can be retrieved from the gNB hosting the UE context when the UE resumes to the RRC_CONNECTED state. For signalling-based QoE, at handover to a target gNB that supports QoE measurement collection, the target gNB decides which of the application layer measurement configurations should be kept and which should be released, e.g., based on application layer measurement configuration information received from the source gNB in Xn/NG signalling. When the UE is handed over to a target that does not support QMC, the UE releases all configured application layer measurement configurations. The continuity of QoE measurement configuration and reporting in NR-DC scenario is supported as specified in TS 37.340. QoE measurement collection continuity for intra-system inter-RAT handover is supported. For a handover from a source gNB to a target ng-eNB, measurements continuity for only one QoE measurement configuration can be supported when the UE connects to the target ng-eNB. The source gNB decides which QoE measurement to keep and sends the information about this QoE measurement to the target ng-eNB. For intra-5GC handover from a source ng-eNB to a target gNB, the UE releases all LTE QoE configurations and it applies the NR QoE configuration(s), if received from the target RAT. For intra-5GC handover from a source gNB to a target ng-eNB, the UE releases all NR QoE configuration(s) and it applies the LTE QoE configuration if received.

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 collection 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.

The radio-related measurements may be collected via immediate MDT for all types of supported services for the purpose of QoE analysis. The MCE/TCE performs the correlation of the immediate MDT measurement results and the QoE measurement results collected at the same UE. The following is supported:

• Alignment between a signalling-based QoE measurement and a signalling-based MDT measurement. In this case, the signalling-based QoE configuration sent to the gNB includes the NG-RAN Trace ID of the signalling-based MDT measurement.
• Alignment between a management-based QoE measurement and a management-based MDT measurement.

The UE configured with QoE measurements sends an indication to inform the gNB about the start or the stop of a QoE measurement session of configured QoE measurements. The gNB can activate the MDT measurements that are to be aligned with the QoE measurements performed by the UE upon/after receiving the QoE measurement session start indication from the UE. The gNB may activate the MDT measurements upon/after receiving the MDT activation message from the OAM. The gNB can deactivate the aligned MDT measurements according to an OAM command which may, e.g., be triggered by the session stop indication. The gNB includes time stamp information to the QoE measurement reports to enable the correlation of corresponding measurement results of MDT and QoE at the MCE/TCE. In addition, the gNB includes the MDT session identifiers (Trace Reference and Trace Recording Session Reference) in the corresponding QoE measurement report.

QoE measurements can be confined to high mobility state of the UE and/or to HSDN cells.