Section: 21.3 QoE Measurement Continuity for Mobility
Content: QoE measurement collection continuity for intra-system intra-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 the 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, QoE reference, and, optionally, the MCE IP address, measurement configuration application layer ID, MDT alignment information, area scope, slice support list for QMC, available RAN visible QoE metrics and measurement status are passed to the target gNB. For management-based QoE, the service type indication, measurement configuration application layer ID, the MCE IP address and QoE measurement 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 it 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 or released, e.g., based on application layer measurement configuration information received from the source gNB in Xn/NG signalling. The continuity of QoE measurement configuration and reporting in NR-DC scenario is supported as specified in TS 37.340[ Evolved Universal Terrestrial Radio Access (E-UTRA) and NR; Multi-connectivity; Overall Description; Stage-2 ]  [21]. For QoE sessions pertaining to data flows received via MBS broadcast, QoE measurement collection may continue during the RRC_INACTIVE and RRC_IDLE. Upon UE's transition from RRC_IDLE to RRC_CONNECTED, the gNB serving the UE should ensure that it does not release an already configured signalling-based QoE measurement configuration for the sake of configuring a new management-based QoE measurement configuration. QoE measurements for ongoing sessions should be continued when switching between MBS multicast and unicast transmission modes. When the UE resumes the connection with a gNB that does not support QoE, the UE releases all application layer measurement configurations. QoE measurement collection continuity for intra-system inter-RAT handover is supported. For the handover from NR to LTE, only one QoE measurement can be continued when the UE connects to the target LTE node. 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 E-UTRA to NR, the UE releases the LTE QoE configuration if received from the source RAT and the UE applies NR QoE configuration(s) if received from the target RAT. For intra-5GC handover from NR to E-UTRA, the UE releases all NR QoE configuration(s) if received from the source RAT, and the UE applies the LTE QoE configuration if received from the target RAT.