L.1 Configuration and reporting

26.2473GPPProgressive Download and Dynamic Adaptive Streaming over HTTP (3GP-DASH)Release 17Transparent end-to-end Packet-switched Streaming Service (PSS)TS

Tools: ARFCN - Frequency Conversion for 5G NR/LTE/UMTS/GSM

As an alternative to configuration via MPD or OMA-DM, the QoE configuration can optionally be specified by the QoE Measurement Collection (QMC) functionality. In this case the QoE configuration is received via specific RRC [53] messages for UMTS, RRC [59] messages for LTE, and RRC messages for NR [70] over the control plane, and the QoE reporting is also sent back via RRC messages over the control plane.

If QMC is supported, the UE shall support the following QMC functionalities:

– QoE Configuration: The QoE configuration will be delivered via RRC to the UE as a container according to "Application Layer Measurement Configuration" (see [53]) for UMTS, "measConfigAppLayer" (see [59]) for LTE and “AppLayerMeasConfig” (see [70]) for NR. The container is an octet string with gzip-encoded data (see [18]) stored in network byte order . The maximum size of the container is 1000 bytes for UMTS (see [53]) and LTE (see [59]), and 8000 bytes for NR (see [70]). The container shall be uncompressed, and is then expected to conform to XML-formatted QoE configuration data according to clause L.2 in the current specification. This QoE Configuration shall be forwarded to the DASH client. The interface towards the RRC signalling is handled by the AT command +CAPPLEVMC for UMTS and LTE, and AT command +CAPPLEVMCNR for NR [61].

– QoE Metrics: QoE Metrics from the DASH client shall be XML-formatted according to clause 10.6 in the current specification. The XML data shall be compressed with gzip (see [18]) and stored in network byte order into an octet string container. The maximum size of the container is 8000 bytes for UMTS (see [53]) and LTE (see [59]). For NR [70], the maximum size is 8000 bytes if RRC segmentation is not enabled, and 144000 bytes if enabled. The container shall be delivered via RRC to the RNC according to "Application Layer Measurement Reporting" (see [53]) for UMTS, to the eNB according to "measReportAppLayer" (see [59]) for LTE, and to the gNB according to “MeasurementReportAppLayer” (see [70]) for NR. The behaviour if the compressed data is larger than the maximum container size is unspecified in this version of the specification. The interface towards the RRC signalling is handled by the AT command +CAPPLEVMR for UMTS and LTE, and AT command +CAPPLEVMRNR for NR[61].

– The UE shall also set the QMC capability "QoE Measurement Collection for streaming services" (see [53]) to TRUE for UMTS, include the QMC capability "qoe-MeasReport" (see [59]) for LTE and include the QMC capability “qoe-Streaming-MeasReport” (see [70]) for NR.

– The QoE configuration AT command +CAPPLEVMC or AT command +CAPPLEVMCNR [61] may also indicate with an Within-area Indication if the UE is inside or outside a wanted geographic area. Such an indication may arrive with or without any QoE configuration container attached. If the DASH client is informed that it is not inside the area, it shall not start any new QoE measurements even if it has received a valid QoE configuration container, but shall continue measuring for already started sessions.

– When a new session is started, the QoE reporting AT command +CAPPLEVMR or AT command +CAPPLEVMRNR [61] shall be used to send a Recording Session Indication. Such an indication does not contain any QoE report, but indicates that QoE recording has started for a session.

– When the QoE configuration is to be released, an unsolicited result code, associated with the AT command +CAPPLEVMC or AT command +CAPPLEVMCNR [61] and containing the parameter <start-stop_reporting> set to "1" shall be sent to the DASH client as notification of a discard request. Then the DASH client shall stop collecting quality metrics and discard any already collected information [63].

For NR, the RAN visible QoE may be supported. The gNB can use RAN visible QoE configurations to instruct the UE to collect application layer measurements for network optimization.

– The RAN visible QoE configuration generated by the gNB shall be forwarded to the DASH client, including the required RAN visible QoE metrics, service type, the RRC identifier and optionally reporting periodicity. The set of RAN visible QoE metrics is a subset of the QoE metrics defined in clause 10.6. The reporting periodicity follow the baseline NR QoE configuration when the reporting periodicity is not included.

– Based on the RAN visible QoE configuration, the RAN visible QoE report shall be directly delivered to the UE AS layer and the collected metrics shall be sent to the gNB via the “MeasurementReportAppLayer” message.

– When the RAN visible QoE measurement is deactivated by the gNB, the DASH client shall be notified to terminate and release the RAN visible QoE measurement.

NOTE: The RAN visible QoE metrics collection can be configured only if baseline NR QoE measurements are configured for the same service type. When the baseline NR QoE measurements are released, the RAN visible QoE configuration shall also be released.

The exact implementation is not specified here, but example signalling diagrams for UMTS, LTE and NR below show the QMC functionality with a hypothetical "QMC Handler" entity.

Figure L-1: Example signalling diagram for UMTS

Figure L-2: Example signalling diagram for LTE

Figure L-3: Example signalling diagram for NR

Note that the QMC Handler is only shown here as one possible implementation, and it need not be implemented as such. The corresponding QMC functionality could be built into the DASH client or into other UE entities. In this version of the specification the detailed implementation of the above functionalities is left to the UE vendor.