Section: 8.13.2 Management based MDT activation 8.13.2.1 General
Content: In Management Based Trace Activation towards a gNB-CU-CP, gNB-CU-UP or a gNB-DU can be fulfilled with the Cell Traffic trace functionality defined in TS 32.422[ Telecommunication management; Subscriber and equipment trace; Trace control and configuration management ]  [20]. The configuration parameters of the Trace Session that are received by a node in split RAN architecture are defined in TS 32.422[ Telecommunication management; Subscriber and equipment trace; Trace control and configuration management ]  [20]. The following description is valid for both an en-gNB and a gNB. If the MDT measurement is initiated by the EM towards the gNB-CU-CP, and if the activation involves measurements collected by multiple nodes under the same gNB-CU-CP control in a split RAN architecture, the EM sends MDT measurement activation to the gNB-CU-CP and the gNB-CU-CP may further decide which gNB-DU(s) or which gNB-CU-UP(s) to perform the MDT measurement. When gNB-CU-CP or a gNB-DU receive the Trace Session Activation message from the management system for a given cell or a list of cell(s) under its control, the gNB-CU-CP or gNB-DU shall start a Trace Session for the given cell or list of cell(s). For Management Based MDT sent directly to a gNB-CU-UP, no MDT Area Configuration (apart from PLMN IDs) is to be included in the MDT activation indication. The signalling flows for management based MDT activation in gNB-CU-CP, gNB-DU and gNB-CU-UP are shown in Figure 8.13.2.2-1, Figure 8.13.2.3-1 and in Figure 8.13.2.4-1 respectively.