8.10 Trace Procedures

36.4133GPPEvolved Universal Terrestrial Radio Access Network (E-UTRAN)Release 17S1 Application Protocol (S1AP)TS

8.10.1 Trace Start

8.10.1.1 General

The purpose of the Trace Start procedure is to allow the MME to request the eNB to initiate a trace function for a UE. The procedure uses UE-associated signalling. If no UE-associated logical S1-connection exists, the UE-associated logical S1-connection shall be established as part of the procedure.

8.10.1.2 Successful Operation

Figure 8.10.1.2-1: Trace Start procedure.

The MME initiates the procedure by sending a TRACE START message. On receipt of a TRACE START message, the eNB shall initiate the requested trace function as described in TS 32.422 [10].

If the Trace Activation IE is included in the TRACE START message which includes the MDT Activation IE set to “Immediate MDT and Trace”, the eNB shall if supported, initiate the requested trace session and MDT session as described in TS 32.422 [10].

If the Trace Activation IE is included in the TRACE START message which includes the MDT Activation IE set to “Immediate MDT Only”, “Logged MDT only” or “Logged MBSFN MDT”, the target eNB shall, if supported, initiate the requested MDT session as described in TS 32.422 [10] and the target eNB shall ignore Interfaces To Trace IE, and Trace Depth IE.

If the Trace Activation IE includes the MDT Location Information IE, within the MDT Configuration IE, the eNB shall, if supported, store this information and take it into account in the requested MDT session.

If the Trace Activation IE is included in the TRACE START message which includes the MDT Activation IE set to “Immediate MDT Only”, “Logged MDT only” or “Logged MBSFN MDT” and if the Signalling based MDT PLMN List IE is included in the MDT Configuration IE, the eNB may use it to propagate the MDT Configuration as described in TS 37.320 [31].

If the Trace Activation IE includes the MBSFN-ResultToLog IE, within the MDT Configuration IE, the eNB shall, if supported, take it into account for MDT Configuration as described in TS 37.320 [31].

If the Trace Activation IE includes the MBSFN-AreaId IE in the MBSFN-ResultToLog IE, within the MDT Configuration IE, the eNB shall, if supported, take it into account for MDT Configuration as described in TS 37.320 [31].

If the Trace Activation IE includes the UE Application layer measurement configuration IE, the eNB shall, if supported, initiate the requested trace session and QoE Measurement Collection function as described in TS 36.300 [14].

If the Trace Activation IE includes the Bluetooth Measurement Configuration IE, within the MDT Configuration IE, the eNB shall, if supported, take it into account for MDT Configuration as described in TS 37.320 [31].

If the Trace Activation IE includes the WLAN Measurement Configuration IE, within the MDT Configuration IE, the eNB shall, if supported, take it into account for MDT Configuration as described in TS 37.320 [31].

If the Trace Activation IE includes the MDT Configuration NR IE, the eNB shall, if supported, store and forward MDT Configuration NR IE to the SgNB, if the eNB has configured EN-DC for the UE.

If the Trace Activation IE includes the Sensor Measurement Configuration IE within the MDT Configuration IE, take it into account for MDT Configuration as described in TS 37.320 [31].

Interactions with other procedures:

If the eNB is not able to initiate the trace session due to ongoing handover of the UE to another eNB, the eNB shall initiate a Trace Failure Indication procedure with the appropriate cause value.

8.10.2 Trace Failure Indication

8.10.2.1 General

The purpose of the Trace Failure Indication procedure is to allow the eNB to inform the MME that a Trace Start procedure or a Deactivate Trace procedure has failed due to an interaction with a handover procedure. The procedure uses UE-associated signalling.

8.10.2.2 Successful Operation

Figure 8.10.2.2-1: Trace Failure Indication procedure.

The eNB initiates the procedure by sending a TRACE FAILURE INDICATION message. Upon reception of the TRACE FAILURE INDICATION message, the MME shall take appropriate actions based on the failure reason indicated by the Cause IE.

8.10.3 Deactivate Trace

8.10.3.1 General

The purpose of the Deactivate Trace procedure is to allow the MME to request the eNB to stop the trace session, for the indicated trace reference.

8.10.3.2 Successful Operation

Figure 8.10.3.2-1: Deactivate Trace procedure. Successful operation.

The MME invokes the Deactivate Trace procedure by sending a DEACTIVATE TRACE message to the eNB as described in TS 32.422 [10].

Upon reception of this message, the eNB shall stop the trace session for the indicated trace reference in the E-UTRAN Trace ID IE.

Interactions with other procedures:

If the eNB is not able to stop the trace session due to ongoing handover of the UE to another eNB, the eNB shall initiate a Trace Failure Indication procedure with the appropriate cause value.

8.10.4 Cell Traffic Trace

8.10.4.1 General

The purpose of the Cell Traffic Trace procedure is to send the allocated Trace Recording Session Reference and the Trace Reference to MME. The procedure uses UE-associated signalling.

8.10.4.2 Successful Operation

Figure 8.10.4.2-1: Cell Traffic Trace procedure. Successful operation.

The procedure is initiated with a CELL TRAFFIC TRACE message sent from the eNB to the MME.

If the Privacy Indicator IE is included in the message, the MME shall take the information into account for anonymisation of MDT data (TS 32.422 [10]).