4.10 Handling of MDT trace sessions at handover for immediate MDT in NG-RAN

32.4223GPPRelease 17Subscriber and equipment traceTelecommunication managementTrace control and configuration managementTS

The gNB shall activate the Immediate MDT in the UE if the area based selection conditions are satisfied or not in the target cell after a handover that is made over Xn or N2. If the area based selection conditions are not satisfied in the handover target cell, the gNB may deactivate the Immediate MDT in the UE. The trace sessions and trace recording sessions are not visible for the UE.

In case of signalling based trace activation , the gNB shall propagate the Trace Session parameters together with the MDT specific parameters to the target cell regardless of whether the source or target cell is part of the configured area scope in case of an Intra-PLMN handover over Xn or N2.

For NG-RAN, the MDT configuration received by signalling based trace messages for a specific UE will propagate during intra-PLMN handover and may propagate during inter-PLMN handover if the Signalling Based MDT PLMN List is available and includes the target PLMN. This behaviour applies also for MDT configuration that includes area scope, regardless of whether the source or target cell is part of the configured area scope.

For signalling based MDT configuration , when a UE that has been configured with MDT hands over to another gNB (i.e. in connected mode) and the Signalling Based MDT PLMN List conditions mentioned above are satisfied:

– with an Xn handover for the case of intra-RAT: the MDT configuration shall be passed to the gNB in the Xn handover request for continuity of MDT data collection. The new gNB shall stop the MDT collection if the new conditions are not within the criteria for MDT data collection.

– with an Xn handover for the case of inter-RAT: the MDT configuraiton shall be passed to the eNB or gNB in the Xn handover request for continuity of MDT data collection.

– with an N2 handover and with no AMF relocation: with N2 handover the AMF shall ensure the MDT configuration is sent to the new gNB.

– with an N2 handover and with AMF relocation: MDT configuration shall be passed on to the new AMF on AMF relocation. During inter-AMF handover, the AMF shall propagate the MDT configuration parameters to the target AMF within an N14- Forward Relocation Request message as part of inter-AMF handover procedures. The new AMF shall save the information as part of the UE context and forward the MDT configuration to the new gNB.

The following MDT configuration shall be passed during handovers (Either intra-gNB, inter-gNB or inter-AMF HO):

– Trace Reference

– Trace Recording Session Reference

– Area Scope

– List of Measurements

– Report Amount

– Reporting Trigger

– Event Threshold

– Report Interval

– TCE IP Address

– Job Type

– Positioning Method

– Collection period for RRM measurements NR (present only if any of M4 or M5 measurements are requested)

– Collection Period M6 in NR (present only if any of M6 measurements (DL or UL) is requested).

– Collection Period M7 in NR (present only if any of M7 measurements (DL or UL)is requested).

– MDT PLMN List

– Sensor Information

– Excess packet delay thresholds (present only if M6 UL measurements are requested)

Note that at the same time not all the parameters can be present. The conditions are described in clause 5.10 of the present document.