4.1.2 Signalling activation

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

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

4.1.2.1 General

4.1.2.1.1 General signalling activation mechanisms for UMTS and EPS

In Signalling activation, the Trace Activation shall be carried out from the Core Network EM only [EM (PS), EM (CS), EM (HSS), EM (UE) and EM(EPC) are generally considered to be in the Core Network. A Core Network EM can be any of these or their combinations].

In case of home subscriber trace (i.e. in the HPLMN) the Trace Session activation shall go to the HSS / MSC Server / SGSN / MME. Instances where the home subscriber is roaming in a VPLMN, the HSS may initiate a trace in that VPLMN. The VPLMN may reject such requests.

In case of foreign subscriber trace (i.e. the HPLMN operator wishes to trace foreign subscribers roaming in his PLMN) the Trace Session activation shall go the MSC Server/VLR, SGSN / MME. Depending on the Trace Control and Configuration parameters received, the Core Network shall propagate the activation to selected NE’s in the entire network – RAN and Core Network.

If the NE failed to activate the Trace Session, a Trace failure notification shall be sent to the TCE, and the Trace failure notification has the the same parameters as the notification notifyTraceRecordingSessionFailure defined in 3GPP TS 32.442 [24], the Trace failure notification file XML schema is defined in Annex A.

4.1.2.1.2 General signalling activation mechanisms for 5GS

In 5GS the signaling trace activation utilizes the Services Based Management Architecture (SBMA) defined in TS 28.533 [48]. A 5GC NE is configured with Trace Control and Configuration parameters via interaction between Provisioning MnS (see definitions in TS 28.532 [47]) consumer and Provisioning MnS producer. Figure 4.1.2.1.2-1 below illustrates the 5GS signaling activation where the role of a Provisioning MnS producer is played by the 5GC NE and the role of a Provisioning MnS consumer is played by the Management System.

In case of home subscriber trace (i.e. in the HPLMN), the Trace Session activation shall go to the 5GC NE which played as the Provisioning MnS producer, such as UDM, AMF and SMF. Instances where the home subscriber is roaming in a VPLMN, the Provisioning MnS producer may initiate a trace in that VPLMN. The VPLMN may reject such requests.

In case of foreign subscriber trace (i.e. the HPLMN operator wishes to trace foreign subscribers roaming in his PLMN), the Trace Session activation shall go to the 5GC NE located in the PLMN operator (i.e. the 5GC NE belongs to VPLMN as described in clause 4.2.4 of TS 23.501 [40], such as AMF/SMF).

Depending on the Trace Control and Configuration parameters received, the configured 5GC NE shall propagate the activation to selected NE’s in the entire network – RAN and Core Network.

Figure 4.1.2.1.2-1: Overview of signaling activation for 5GS

If the NE failed to activate the Trace Session in a file-based reporting case, a Trace failure notification shall be sent to the TCE. XML based encoding of the Trace failure notification shall follow the Trace failure notification file XML schema defined in Annex A. Administrative messages can also be used if the NE failed to activate a Trace Session, or if there are errors for an ongoing session, and are included in the trace data. An example of an administrative message is the Trace File Abnormal Closed administrative message (see 3GPP TS 32.423 [3]).

4.1.2.2 Intra PLMN signalling activation for UMTS and EPS

The following figure represents the signalling based trace functionality within a PLMN. The figure represents a typical PLMN network. A dotted arrow with "Trace Parameter Configuration" represents the availability of the trace functionality at the EM for that domain. However, it can be done from the EM (CS Domain). Similarly "Trace Parameter Propagation" is allowed only for the interfaces indicated in the figure. E.g. there is no parameter propagation over Iu-B.

The trace propagation across multiple PLMNs of the same operator (e.g. deployment scenario where UMTS part of the network has one PLMN and LTE part of the network as another PLMN) follows the rules of the Intra-PLMN signalling activation.

NOTE: For tracing on the basis of IMEI(SV), the signalling based activation can be only initiated from the MSC/VLR or SGSN.

Figure 4.1.2.2.1: Overview of Intra-PLMN Signalling Activation for UMTS and EPS

4.1.2.3 Inter PLMN Signalling Activation for UMTS and EPS

The following figure represents the signalling based trace functionality between PLMNs. This is particularly useful when a roaming subscriber needs to be traced in a network. The figure represents a typical PLMN network and its connections with another PLMN’s HSS. A dotted arrow with "Trace Parameter Configuration" represents the availability of the trace functionality at the EM for that domain. E.g. you cannot invoke a Signalling Trace at the EM (UTRAN) because there is no such arrow shown in the figure. You can however do it from the EM (CS Domain). Similarly "Trace Parameter Propagation" is allowed only for the interfaces indicated in the figure. E.g. there is no parameter propagation over Iu-B.

NOTE: There is no intention to allow tracing of a home subscriber roaming in a foreign network i.e. the trace function is limited to PLMNs of a single operator.

Figure 4.1.2.3.1: Overview of Inter-PLMN Signalling Activation for UMTS and EPS

4.1.2.4 UTRAN activation mechanisms

See subclause 4.2.3.1.

4.1.2.5 PS Domain activation mechanisms

The following figure shows the Trace Session activation in the PS domain. The figure is an example of tracing PDP context.

Figure 4.1.2.5.1: Trace session activation in PS domain for PDP Context

When SGSN receives the MAP-ACTIVATE_TRACE_MODE message it shall store the trace control and configuration parameters and shall start a Trace Session.

When any of the triggering events defined in the trace control and configuration parameters occur, (e.g. PS session is started (i.e. a ACTIVATE PDP CONTEXT REQUEST message is received from the UE)) the SGSN shall propagate the trace control and configuration parameters to the GGSN (by sending a GTP-CREATE_PDP_CONTEXT_REQUEST message) and to the radio network (by sending a RANAP-CN_INVOKE_TRACE message), if it is defined in the trace control and configuration parameters (NE types to trace). The Trace Session activation to UTRAN is described in clauses 4.1.2.4.

When HSS sends the MAP-ACTIVATE_TRACE_MODE message to SGSN it shall include the following parameters to the message (The values related to the EPS domain shall be used for the Trace Session activation through the S3 interface in case of an Inter-RAT handover event.):

– Trace Target: IMSI (M).

– Trace Reference (M).

– Triggering Events for SGSN (M) , GGSN (M) , MME (M), Serving GW(M) and PDN GW(M).

– Trace Depth (M).

– List of NE Types to trace (M).

– List of Interfaces for SGSN (O), GGSN (O) and/or RNC (O) , MME (O), Serving GW (O), PDN GW(O), eNB(O).

– Trace Collection Entity IP Address (O).

When the SGSN sends the GTP-CREATE_PDP_CONTEXT_REQUEST message to GGSN it shall include the following parameters to the message:

– Trace Target: IMSI or IMEI(SV) (M).

– Trace Reference (M).

– Trace Recording Session Reference (M).

– Triggering Events for GGSN (M).

– Trace Depth (M).

– List of Interfaces for GGSN (O).

– Trace Collection Entity IP Address (O).

Figure 4.1.2.5.2 is an example of tracing for MBMS Context.

Figure 4.1.2.5.2: Trace session activation in PS domain for MBMSContext

When HSS receives a Trace Session activation from its EMS, it shall store the received trace control and configuration parameters. At this point a Trace Session shall be started in the HSS.

When SGSN receives the MAP-ACTIVATE_TRACE_MODE message it shall store the trace control and configuration parameters and shall start a Trace Session.

In case of an inter-SGSN handover the trace control and configuration parameters (both PS domain specific and EPS domain specific parameters) shall be propagated to the target SGSN.

In case of an inter-RAT handover the SGSN shall send the PS and EPS specific Trace control and configuration parameters to the target MME via the S3 interface.

When any of the triggering events defined in the trace control and configuration parameters occur, (i.e. an ACTIVATE MBMS CONTEXT REQUEST message is sent to the UE)) the SGSN shall propagate the trace control and configuration parameters to the GGSN (by sending a GTP-CREATE_MBMS_CONTEXT_REQUEST message) and to the radio network (by sending a RANAP-CN_INVOKE_TRACE message), if it is defined in the trace control and configuration parameters (NE types to trace). The Trace Session activation to UTRAN is described in clauses 4.1.2.4.

The GGSN shall propagate the trace control and configuration parameters to the BM-SC (by sending a Diameter Gmb AAR message) if the BM-SC is defined in the trace control and configuration parameters (NE types to trace).

When HSS sends the MAP-ACTIVATE_TRACE_MODE message to SGSN it shall include the following parameters in the message:

– Trace Target: IMSI (M).

– Trace Reference (M).

– Triggering Events for SGSN (M), GGSN (M) and BM-SC (M).

– Trace Depth (M).

– List of NE Types to trace (M).

– List of Interfaces for SGSN (O), GGSN (O), BM-SC (O) and/or RNC (O).

– Trace Collection Entity IP Address (O).

When the SGSN sends the GTP-CREATE_MBMS_CONTEXT_REQUEST message to GGSN it shall include the following parameters in the message:

– Trace Target: IMSI or IMEI(SV) (M).

– Trace Reference (M).

– Trace Recording Session Reference (M).

– Triggering Events for GGSN (M) and BM-SC (M).

– Trace Depth (M).

– List of Interfaces for GGSN (O) and BM-SC (O).

– Trace Collection Entity IP Address (O).

When the GGSN sends the Diameter Gmb AAR message to the BM-SC it shall include the following parameters in the message:

– Trace Target: IMSI or IMEI(SV) (M).

– Trace Reference (M).

– Trace Recording Session Reference (M).

– Triggering Events for BM-SC (M).

– Trace Depth (M).

– List of Interfaces for BM-SC (O).

– Trace Collection Entity IP Address (O).

4.1.2.6 CS Domain activation mechanisms

Figure 4.1.2.6.1 shows the Trace Session activation in the CS domain. The figure is an example of tracing Mobile Originating Call.

Figure 4.1.2.6.1: Trace Session Activation in CS domain

When HSS receives Trace Session activation from the EMS it should store the trace control and configuration parameters associated to the Trace Session.

If the UE registers to the network, by sending a LOCATION UPDATING REQUEST message to the MSC/VLR, the MSC Server/VLR updates the location information in the HSS by sending the MAP-UPDATE_LOCATION message to the HSS. After receiving the UPDATE_LOCATION message HSS shall propagate the trace control and configuration parameters by sending a MAP-ACTIVATE_TRACE_MODE message to the MSC Server/VLR.

When the MSC Server/VLR receives the MAP-ACTIVATE_TRACE_MODE message from the HSS, it shall store the trace control and configuration parameters.

When any of the triggering event, defined in the trace control and configuration parameters, occurs (e.g. in case of Mobile Originating Call is started (i.e. the MSC Server receives the CM_SERVICE_REQUEST message with service type set to originating call establishment)) the MSC Server should propagate the trace control and configuration parameters to the MGW (by sending an ADD command with a trace package – see 3GPP TS 29.232 [10]) and to the radio network if it is defined in the trace control and configuration parameters (NE types to trace). Trace Session activation for UTRAN is described in clauses 4.1.2.4. In case of inter-MSC Server handover the MSC Server-A should propagate the trace control and configuration parameters to the MSC Server-B.

When HSS sends the MAP-ACTIVATE_TRACE_MODE message to MSC Server it shall include the following parameters to the message:

– Trace Target: IMSI (M).

– Trace Reference (M).

– Triggering Events for MSC Server (M) and MGW (M).

– Trace Depth (M).

– List of NE Types to trace (M).

– List of Interfaces for MSC Server (O), MGW (O) and/or RNC (O).

– Trace Collection Entity IP Address (O).

When the MSC Server sends the ADD command with trace package to MGW it shall include the following parameters to the message:

– Trace Target: IMSI or IMEI(SV) (M).

– Trace Reference (M).

– Trace Recording Session Reference (M).

– Triggering Events for MGW (M).

– Trace Depth (M).

– List of Interfaces for MGW (O).

– Trace Collection Entity (O) IP Address.

4.1.2.7 Void

4.1.2.8 Tracing roaming subscribers

If a HPLMN operator activates a Trace Session for a home subscriber, while it (MS) is roaming in a VPLMN, it (HSS or UDM) may restrict the propagation of the Trace Session activation message to a MSC Server/VLR or to a SGSN or to a SMF located in the VPLMN.

Also, a MSC Server/VLR, a SGSN or a SMF located in a VPLMN may accept any Trace Session activation message(s) coming from an HSS or UDM located in another PLMN. However, there shall be a capability to reject activations from another PLMN.

4.1.2.9 Service Level Tracing for IMS activation mechanisms

4.1.2.9.1 General

Figure 4.1.2.9.1.1 illustrates signalling based activation for service level tracing within a home IM CN SS and a visited IM CN SS. An arrow with "Trace Parameter Configuration" represents the availability of the trace functionality at the EM for that domain. Similarly, An arrow with "Trace Parameter Propagation" represents the ability to propagate trace parameters only for the interfaces indicated.

Figure 4.1.2.9.1.1: Overview of Signalling Activation for service level tracing for IMS

Trace Activation shall be initiated from the Core Network EM only [EM (UE), and EM (HSS)].

The EM (UE) and the interactions between the EM (UE) and the UE shall be achieved using OMA Device Management [18].

When service level tracing for IMS is required for a registered home subscriber in the home IM CN SS Trace Session activation shall go to the UE and the HSS. The HSS shall propagate the Trace Session activation to the S-CSCF, I-CSCF and the AS.

The S-CSCF and I-CSCF shall propagate the Trace Session activation to the P-CSCF. The Trace Session activation shall be propagated to the MRF, MGCF and BGCF via the S-CSCF. When an IMS NE (i.e. S/I/P-CSCF, AS, HSS, MRF, MGCF, BGCF) receives Trace Session activation it shall save the received Trace control and configuration parameters and shall start a Trace Session.

When service level tracing for IMS is required for a registered home subscriber in a visited IM CN SS Trace Session activation shall go to the UE and the HSS. The HSS shall propagate the Trace Session activation to the S-CSCF, I-CSCF and the AS. The I-CSCF may prohibit the propagation of the Trace Session activation from the home IM CN SS to the P-CSCF in the visited IM CN SS.

4.1.2.9.2 Trace session activation for non-registered UE

Figure 4.1.2.9.2.1 illustrates the sending of Trace Session activation towards the HSS, S-CSCF, I-CSCF, AS and
P-CSCF during the registration of a UE with the IM CN SS.

As described in 3GPP TS 23.228 [15] for the purposes of signalling flows the user is considered always to be roaming. For a user roaming in their home network, the home network shall perform the role of the visited network elements and the home network elements.

NOTE: For detailed information of application level registration procedures for IMS see 3GPP TS 23.228 [15].

Figure 4.1.2.9.2.1: Trace Session activation for non-registered user

When HSS receives Trace Session activation from its EM (Step 1), it shall update the user information associated with the user for whom the trace is to be applied (Step 2). The HSS shall store the received trace control and configuration parameters (Step 3). At this point a Trace Session shall be started in the HSS.

When the EM sends the Trace Session activation to the HSS it shall include the following trace and configuration parameters in the message:

– Trace Target: Public User Identity (i.e. Identity of user initiating/terminating the service to be traced) (M)

– Service identification (M)

– Trace Reference (M)

– Triggering Events for HSS (M)

– Trace Depth (M)

– List of NE Types (M)

– Triggering Events for S-CSCF (M), I-CSCF (M), P-CSCF (M), AS (M), BGCF (M), MRF (M), MGCF (M)

When the EM sends the Trace Session activation to the HSS it may include the following trace and configuration parameters in the message if required:

– List of Interfaces for HSS (O)

– List of Interfaces for S-CSCF (O), I-CSCF (O), P-CSCF (O), AS (O), BGCF (O), MRF (O), MGCF (O).

As described in 3GPP TS 23.228 [15] when a UE registers with the network by sending a REGISTER message (Steps 4 to 10), the HSS sends Service Control (user and filter information) to the S-CSCF (Steps 11). It shall also propagate trace control and configuration parameters to the S-CSCF. At this point a Trace Session shall be started in the S-CSCF (Step 12).

When the HSS sends the Cx-Put-Response operation to the S-CSCF (see 3GPP TS 29.228 [16]) it shall include the following trace and configuration parameters:

– Trace Target: Public User Identity (i.e. Identity of user initiating/terminating the service to be traced) (M)

– Service identification (M)

– Trace Reference (M)

– Triggering Events for S-CSCF (M)

– Trace Depth (M)

– List of NE Types (M)

– Triggering Events for I-CSCF (M), P-CSCF (M), BGCF (M), MGCF (M)

When the HSS sends the Cx-Put-Response operation to the S-CSCF it may include the following trace and configuration parameters if required:

– List of Interfaces for S-CSCF (O)

– List of Interfaces for I-CSCF (O), P-CSCF (O), BGCF (O), MGCF (O)

As described in 3GPP TS 23.218 [14] on reception of a REGISTER request, the S-CSCF shall send a third-party REGISTER request to the Application Server if the registration request from the user matches a contained trigger as downloaded from the HSS (Step 13 and 14).

As described in 3GPP TS 29.328 [17] the Application Server shall request from the HSS information such as service and user related information. In this case, the HSS shall determine that a trace request for the user is active and shall return to the Application Server trace control and configuration parameters (Step 16). At this point a Trace Session shall be started in the AS (Step 17).

When the HSS sends the Sh-Pull-Response operation to the AS (see 3GPP TS 29.328 [17]) it shall include the following trace and configuration parameters:

– Trace Target: Public User Identity (i.e. Identity of user initiating/terminating the service to be traced) (M).

– Service identification (M)

– Trace Reference (M)

– Triggering Events for AS (M)

– Trace Depth (M)

– List of NE Types (M)

– Triggering Events for MRF (M)

When the HSS sends the Sh-Pull-Response operation to the AS it may include the following trace and configuration parameters if required:

– List of Interfaces for AS (O)

– List of Interfaces for MRF (O)

Upon successful registration the S-CSCF shall return a SIP 200 OK and shall propagate the received trace control and configuration parameters to the I-CSCF (Step 18). At this point a Trace Session shall be started in the I-CSCF (Step 19).

When the S-CSCF sends the 200 OK (Register) message to the I-CSCF (see 3GPP TS 24.228 [15]) it shall include the following trace and configuration parameters:

– Trace Target: Public User Identity (i.e. Identity of user initiating/terminating the service to be traced) (M).

– Service identification (M)

– Trace Reference (M)

– Trace Depth (M)

– Triggering Events for I-CSCF (M)

– List of NE Types (M)

– Triggering Events for P-CSCF (M)

When the S-CSCF sends the 200 OK (Register) message to the I-CSCF it may include the following trace and configuration parameters if required:

– List of interfaces for I-CSCF (O)

– List of interfaces for P-CSCF (O)

If the P-CSCF resides in the same (i.e. home IM CN SS) network as the I-CSCF, the I-CSCF forwards the SIP 200 OK and shall propagate the retrieved trace control and configuration parameters to the P-CSCF (Step 20). At this point a Trace Session shall be started in the P-CSCF (Step 21).

When the I-CSCF sends the 200 OK (Register) message to the P-CSCF (see 3GPP TS 24.228 [15]) it shall include the following trace and configuration parameters:

– Trace Target: Public User Identity (i.e. Identity of user initiating/terminating the traced service) (M)

– Service identification (M)

– Trace Reference (M)

– Trace Depth (M)

– Triggering Events for P-CSCF (M)

– List of NE Types (M)

When the I-CSCF sends the 200 OK (Register) message to the P-CSCF it may include the following trace and configuration parameters if required:

– List of Interfaces for P-CSCF (O).

If the P-CSCF resides in a different (i.e. visited IM CN SS) network as the I-CSCF, the I-CSCF forwards the SIP 200 OK and may propagate the retrieved trace control and configuration parameters to the P-CSCF. If the P-CSCF is in a different network than the I-CSCF and the sending of trace control and configuration parameters from the home IM CN SS to the visited IM CN SS is prohibited then the I-CSCF shall restrict the sending of the trace control and configuration parameters.

The P-CSCF shall forward the SIP 200 OK to the UE. The P-CSCF shall not send the retrieved trace control and configuration parameters.

4.1.2.9.3 Trace session activation for a registered UE

Figure 4.1.2.9.3.1 illustrates the sending of Trace Session activation towards the HSS, S-CSCF, I-CSCF, AS and P-CSCF during the re-registration of a UE with the IM CN SS.

As described in 3GPP TS 23.228 [15] periodic application level re-registration is initiated by the UE either to refresh an existing registration or in response to a change in the registration status of the UE. Re-registration follows the same process as that defined for registration of a non-registered user.

Figure 4.1.2.9.3.1: Trace Session activation for registered UE

When the EM sends the Trace Session activation to the HSS it shall include the trace and configuration parameters as described in clause 4.1.2.9.2.

Prior to expiry of the agreed registration timer, the UE initiates a re-registration by sending a REGISTER message.
The subsequent steps of re-registration of the UE as described in 3GPP TS 23.228 [15] and the signalling flow steps as described in subclause 4.1.2.9.2 apply.

The IM CN SS shall request a re-authentication of a registered UE when Trace Session activation is required before the UE performs a periodic re-registration, and when the subscription status of the registered UE is not to be affected.

Following a network initiated re-authentication, the UE shall re-register with the IM CN SS and the procedures described for Trace Session activation for a registered UE shall apply.

4.1.2.9.4 Trace session activation at the UE

Figure 4.1.2.9.4.1 illustrates the sending of Trace Session activation from the Device Management Server (DMS) to a UE and the subsequent propagation of a SIP message including a start trigger event from the UE and the P-CSCF.

Figure 4.1.2.9.4.1: Trace Session activation at a UE

A management session shall be established (Step 1) in accordance with OMA Device Management [18]. When a UE receives Trace Session Activation (Step 2) as part of the received management operation it shall store the Trace Control and configuration parameters, and may (e.g. depending on Operator conditions) start a trace session (Step 3).

When any of the triggering events occur at the UE (e.g. the service to be traced from the traced UE is initiated), and when the condition(s) as defined by the trace control and configuration parameters within the received management operation occur, the UE shall start a trace recording (Step 4). As described in subclause 4.2.3.5 the UE shall include in the outgoing SIP (service) signalling message (e.g. INVITE) a Start Trigger Event (Step 5).

4.1.2.10 EPC activation mechanism

4.1.2.10.1 UE attached to EPC via E-UTRAN

Figure 4.1.2.10.1 summarizes the Trace Session activation procedure in EPC:

Figure 4.1.2.10.1: Trace Session activation procedure in EPC with GTP based S5 interface:

The Trace Session activation in MME can come for a home subscriber trace from HSS via the S6a interface or for a foreign subscriber from the EM of MME.

When the UE makes an attach request to the MME, it updates the location information in the HSS. The HSS checks if the UE is being traced. If it is being traced, the HSS shall propagate the trace control and configuration data to the MME by including the trace control and configuration parameters into the S6a-Insert subscriber data message or the S6a-Update Location Answer message. If the traced UE has already attached before receiving the Trace Session Activation from the EM/NM, the HSS shall also propagate the trace control and configuration data to the MME by either S6a-Insert subscriber data message or the S6a-Update Location Answer message. When MME receives the trace control and configuration data from the HSS it shall store the information and shall start a Trace Session.

During inter-MME TAU, the MME shall propagate the trace control and configuration parameters to the target MME within an S10- Context Response as part of inter-MME TAU procedures. During attach procedures where the context information is requested from the target MME, the MME shall propagate the trace control and configuration parameters within an S10-Identification Response message. During inter-MME handover, the MME shall propagate the trace control and configuration parameters to the target MME within an S10- Forward Relocation Request message as part of inter-MME handover procedures. During inter-RAT handover procedure, the MME shall propagate the trace control and configuration parameters to the target SGSN via the S3 interface as part of the inter-RAT handover procedure.

If the List of NE Types parameter specifies tracing in the SGW and/or Tracing in the PGW, MME shall propagate the trace control and configuration parameters via the S11 interface to the SGW per one of the following messages:

1) if a default bearer connection has not been established, via the S11: Create Session Request message;

2) otherwise via the S11-Trace Session Activation message.

The SGW upon receiving the trace control and configuration parameters shall start a trace session.

If the List of NE Types parameter specifies Tracing in the PGW, SGW shall propagate the trace control and configuration parameters via the S5 interface to the PGW per one of the following messages:

1) if a default bearer connection has not been established, via the S5: Create Session Request message;

2) otherwise via the S5-Trace Session Activation message.

The PGW upon receiving the trace control and configuration parameters shall start a trace session.

When a triggering events, defined in the trace control and configuration data occur (i.e. a session is started) a Trace Recording Session should be started and the trace control and configuration data should be propagated to the radio network to the eNB if the List of NE Types parameter specifies eNB tracing. However if the triggering events parameter at MME indicates that all events should be traced, Trace Recording Session shall be started only when the user specific S1 association is setup to the eNB and the Trace Recording Session is kept as long as the user specific S1 association is released or the Trace Session is deactivated. See section 4.2.3.6.

When HSS activates the trace to the MME the following trace control and configuration parameters shall be included in the message (the values related to the PS domain shall be used for Trace Session Activation during inter-RAT handover procedure):

– Trace Target: IMSI or IMEISV

– Trace Reference

– Triggering Events for MME, Serving GW, PDN GW, SGSN, GGSN

– Trace Depth

– List of NE Types to trace

– List of Interfaces for MME, Serving GW, PDN GW, eNB, SGSN, GGSN, RNC

– Trace Collection Entity IP Address

When MME activates the trace to the SGW the following trace control and configuration parameters shall be included in the message:

– Trace Target: IMSI or IMEISV

– Trace Reference

– Triggering Events for Serving GW, PDN GW

– Trace Depth

– List of NE Types to trace

– List of Interfaces for Serving GW, PDN GW

– Trace Collection Entity IP Address

When SGW activates the trace to the PGW the following trace control and configuration parameters shall be included in the message:

– IMSI or IMEISV

– Trace Reference

– Triggering events for PDN GW

– Trace Depth

– List of Interfaces for PDN GW

– Trace Collection Entity IP Address

When MME sends the trace control and configuration parameters to the eNB the following information shall be included in the message:

– Trace Reference

– Trace Recording Session Reference

– Trace Depth

– Trace Collection Entity

and the following information may be included in the message:

– List of Interfaces for eNB

Figure 4.1.2.10.1.A illustrates the Trace Session activation in case of PMIP based S5 interface. The figure contains only the difference compare to the GTP based S5 interface.

Figure 4.1.2.10.1.A: Trace Session Activation from SWG to PGW in case of PMIP based S5 interface

When the SGW receives the Trace Session activation message and the List of NE Type to trace parameter specifies Tracing in the PDN GW , SGW shall send Trace Session Activation to PDN GW via the PCRF. The Trace Session activation can be done as part of the IP CAN session establishment or as a standalone procedure [29].

The Trace Session Activation shall include the following information:

– Trace Target: IMSI or IMEISV

– Trace Reference

– Trace Recording Session Reference

– Trace Depth

– Triggering Events for PDN GW

– List of Interfaces for PDN GW

– Trace Collection Entity IP Address

When the PCRF receives the Trace Session Activation it shall forward the same trace control and configuration parameters to the PDN GW [29].

4.1.2.10.2 UE attached to EPC via non-3GPP accesses with DSMIPv6 on S2c or PMIP on S2a/S2b

Figure 4.1.2.10.2 illustrates the Trace Session activation when the UE is attached from a non-3GPP access network with DSMIPv6 on S2c or PMIP on S2a or S2b interface.

Figure 4.1.2.10.2: Trace Session activation procedure to PGW in case of UE attaches from non-3GPP access network via DSMIPv6 on S2c or PMIP on S2a/S2b

When the UE attaches to the EPC network via a non-3GPP access network the Trace Session activation to the PGW can be done via HSS and AAA server. Therefore when the UE attach is signalled to the HSS via non-3GPP access network, the HSS shall send the Trace control and configuration parameters to the AAA server as part of the user profile download [25]. The following information shall be included in the downloaded user data:

– Trace Target:IMSI, or IMEI(SV)

– Trace Reference

– Triggering Event for PGW

– Trace Depth

– List of Interfaces for PGW

– Trace Collection Entity IP Address

When the AAA server receives the user profile, which contains also the trace control and configuration parameters, it shall store the received trace control and configuration parameters. The AAA server shall forward the received trace control and configuration parameters in the authorization when it receives the authorization request from the PGW during the PDN connectivity.

The event, which triggers the authorization in the PDN GW depend on the used IP mobility protocol:

In case of DSMIP (option A), it is a binding update received from the UE,

In case of PMIP (Option B), it is a proxy binding update request received from the Trusted Non-3GPP GW or ePDG playing the role of the Mobile Access Gateway (MAG)

If the UE is already registered to the HSS by a AAA server via the SWx interface, Trace Session activation shall also be possible from the HSS to the PDN GW via the AAA server. In that case the HSS sends the Trace Session activation message with a push profile request.

The AAA server shall examine the received user profile and if Trace Session activation is needed in the PDN GW, it shall initiate a re-authorization procedure towards the PDN GW. The Trace Session is activated to te PDN GW using this re-authorization procedure. When PDN GW receives the Trace Session activation message, it shall save the received trace control and configuration parameters.

4.1.2.10.3 UE attached to EPC via non-3GPP accesses with GTP on S2b interface

Figure 4.1.2.10.3 illustrates the Trace Session activation when the UE is attached from a non-3GPP access with GTP on the S2b interface.

Figure 4.1.2.10.3: Trace Session activation procedure to PGW when the UE is attaches to EPC from a non-3GPP access with GTP based S2b

When the UE attaches to the EPC network via a non-3GPP access network the Trace Session activation to the PGW can be done via HSS, AAA server and ePDG. Therefore when the UE attach is signalled to the HSS via non-3GPP access network, the HSS shall send the Trace control and configuration parameters to the AAA server as part of the user profile download (see [22] , [25] and [34]).
The following information shall be included in the downloaded user data:

– Trace Target:IMSI, or IMEI(SV)

– Trace Reference

– Triggering Event for PGW

– Trace Depth

– List of Interface for PGW

– Trace Collection Entity IP Address

The ePDG sends a GTPv2 Create Session Request which contains trace information message to the PGW. The RAT type indicates the non-3GPP IP access technology type.

Figure 4.1.2.10.4 illustrates the Trace Session activation when the UE is already attached from a non-3GPP access with GTP based S2b, i.e. trace session activation after a session has been created.

If the UE is already registered to the HSS by a AAA server via the SWx interface, Trace Session activation shall also be possible from the ePDG to the PDN GW. In that case the HSS sends the Trace activation message with a push profile request.

Trace Activation

Figure 4.1.2.10.4: Trace Session activation procedure to PGW when the UE is already attached to EPC from a non-3GPP access with GTP based S2b

The AAA shall examine the received information and if Trace Session activation is needed in the PDN GW, it shall initiate a reauthorization request towards the ePDG. ePDG sends a GTPv2 Trace Session Activation message to the PGW when determining from the updated profile that a trace activation is needed. When PDN GW receives the Trace Session activation message, it shall save the received trace control and configuration parameters.

4.1.2.10.4 Inter-RAT handover from E-UTRAN to UTRAN

The following figure illustrates an example scenario when the UE attaches to the EPC domain, then makes an inter-RAT handover to the UMTS and makes another handover back from UMTS to E-UTRAN.

Figure 4.1.2.10.4.1 Example scenario for Trace Session activation in case of inter-RAT handover

In order to support the inter-RAT trace between EPS and PS domain when the HSS sends the Trace Session Activation message to the SGSN/MME respectively it shall send the trace control and configuration parameters that are applicable for both PS and EPC domains. These parameters shall be transferred in the Trace Session Activation message in the S6a/S6d interface respectively. When MME/SGSN receives the Trace Session Activation message from the HSS or from MME/SGSN the trace control and configuration parameters shall be stored and a Trace Session shall be started.

When the MME sends the Forward Relocation Request messager to the S4-SGSN the MME shall sends the following trace control and configuration parameters for Trace Session activation to the SGSN:

– Trace Target: IMSI or IMEI(SV)

– Trace Reference

– Trace Recording Session Reference

– Trace Depth

– Triggering Events for SGSN, GGSN, RNC, MME, Serving GW, PDN GW and eNB

– List of Interfaces for SGSN, GGSN, RNC, MME, Serving GW, PDN GW and eNB

– Trace Collection Entity IP Address

The Trace Control and Configuration parameters shall be propagated during an inter-RAT handover procedure from the source node to the target node. The propagated Trace Control and Configuration parameters shall include values that are applicable for both EPS and PS domain during the inter-RAT handover procedure.

Similarly, in case of Gn SGSN those parameters shall be transferred through S6a/Gn interface from the HSS to the MME/Gn SGSN. The Trace Control and Configuration parameter of both domain shall be stored in the Trace Session in MME/Gn SGSN respectively.

4.1.2.11 E-UTRAN activation mechanisms

The Trace Session should be activated in in an eNB when the eNB receives the TRACE START, INITIAL CONTEXT SETUP REQUEST or HANDOVER REQUEST message with the IE Trace Activation from the MME and if some activities have been started on the interfaces that have been requested to be traced.

If the subscriber or equipment which is traced makes a handover to a target eNB using the X2 interface, the source eNB should propagate the trace control and configuration parameters further to the target eNB by using the HANDOVER REQUEST message. When the target eNB receives the HANDOVER REQUEST message it should immediately start a Trace Session according to the trace control and configuration parameters received in the HANDOVER REQUEST message.

If the subscriber or equipment which is traced makes a handover to a target eNB using the S1 interface, it is the MME’s responsibility to propagate the trace control and configuration parameters to the target eNB.

Interaction with Relocation

If the tracing shall continue also after the relocation has been performed, the CN Invoke Trace procedure shall be re-initiated from the CN towards the future eNB after the Relocation Resource Allocation procedure has been executed successfully.

The TRACE START, INITIAL CONTEXT SETUP REQUEST or HANDOVER REQUEST message that is received from the MME contains the following information:

– Trace Reference

– Trace Recording Session Reference

– Trace Depth

– List of Interfaces for eNB

– Trace Collection Entity IP Address

If the Trace Reference is the same as an existing Trace Session for the same subscriber or equipment, the eNB shall not activate a new Trace Session and the existing Trace Session will not be impacted. See clause 4.2.3.6 for the conditions on whether or not the Trace Recording Session should be started.

If the Trace Reference is the same as an existing Trace Session for different subscriber(s) or equipment(s), the eNB shall not activate a new Trace Session, and the eNB shall not start a new Trace Recording Session.

4.1.2.12 EPC and E-UTRAN Activation mechanism for MDT

4.1.2.12.1 General

UE measurements activation extends the EPC trace activation procedure, as described in 4.1.2.10. When a Trace Session is activated, configuration parameters of MDT are added into the message.

For IMSI/IMEI(SV)/IMEI-TAC based UE selection, or IMSI/IMEI(SV)/IMEI-TAC combined with geographical area based UE selection, UE performance measurements activation request is propagated to UE finally.

This mechanism works for the following input parameters:

– IMSI only or

– IMSI and area information or

– IMEI(SV) only or

– IMEI(SV) and area information or

– IMEI-TAC only or

– IMEI-TAC and area information

After the IMSI, IMEISV or IMEI-TAC type user attached to the network, the MME shall forward the MDT configurations to the corresponding eNB which serves the IMSI, IMEISV or IMEI-TAC type user. If the area criterion is specified and is not satisfied, the MME shall keep the MDT configuration first and then forward it to the serving eNB only when the area criterion is satisfied.

MDT criteria checking on eNB:

– For immediate MDT, after eNB got the MDT configuration, the eNB can detect the area information and decide whether the selected IMSI/IMEISV can fit into the criteria for initiating MDT data collection. If the area information criterion is not met, the eNB keeps the MDT configuration and propagates it during handover as specified in section 4. 4.

– For logged MDT, the eNB will forward the MDT configuration criteria to the selected IMSI/IMEISV. The area criteria checking will be done at UE side after UE received the MDT configuration criteria.

– For logged MBSFN MDT, the eNB will forward the MDT configuration criteria to the selected IMSI/IMEISV. The area criteria checking will be done at UE side after UE received the MDT configuration criteria.

MDT criteria checking on UE:

– For immediate MDT, there is no need to do MDT criteria checking on UE.

– For logged MDT, The area criteria checking will be done at UE side after UE received the MDT configuration criteria.

In case of logged MDT, after UE receives from eNodeB the configuration parameters via the message RRC Connection Reconfiguration, it detects whether it stays within the specified area. If yes the UE will execute measurement job. Otherwise UE will do nothing but waiting.

In case of Logged MBSFN MDT, after UE receives from eNodeB the configuration parameters via the message RRC Connection Reconfiguration. The UE will log measurements as long as it receives MBMS service from an indicated target MBSFN area and is within the configured logging area.

In case of Immediate MDT trace (e.g., IMSI/IMEI based selection), the Immediate MDT trace session context of the UE shall be preserved in the network when the UE enters idle mode.

The Logged MDT or Logged MBSFN MDT trace session is preserved in the UE until the duration time of the trace session expires, including also multiple idle periods interrupted by idle-connected-idle state transitions.

The Logged MDT trace session context of the UE is stored in the network as long as the trace session is active, including also the periods when the UE is in connected state.

The Logged MBSFN MDT trace session context of the UE is stored in the network as long as the trace session is active, while UE is in idle or connected state.

Two scenarios shall be considered according to UE status when EMS activates MDT job: before UE attachment, after UE attachment, different procedures are described in 4.1.2.12.2, 4.1.2.12.3, 4.1.2.12.5,4.1.2.12.6.

4.1.2.12.2 Activation of MDT task before UE attaches to the network

As shown in figure 4.1.2.12.1, by adding configurations of MDT EMS activate the Trace Session for MDT job.

Figure 4.1.2.12.1: MDT activation procedure in EPC

When HSS activates the trace, for MDT job, to the MME the following configuration parameters shall be included in the message:

– Job Type

– Trace Target: IMSI or IMEISV or IMEI-TAC

– Area Scope (e.g. TA, Cell)

– Trace Reference

– List of Measurements

– Reporting Trigger

– Report Interval

– Report Amount

– Event Threshold

– Logging Interval

– Logging Duration

– Measurement period LTE (if either of the measurements M4, M5 is requested)

– Collection Period for RRM Measurements LTE (present only if M3 measurement is requested).

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

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

– Positioning Method

– MDT PLMN List

– Trace Collection Entity IP Address

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.

The specified geographical area field is available when IMSI/IMEI(SV)/IMEI-TAC combined with geographical area are needed for UE selection.

When MME activate MDT activation to eNodeB, the MDT configuration parameters can be included in the message in the Initial Context Setup:

– Area Scope (TA, Cell)

– Trace Reference

– Trace Recording Session Reference

– List of Measurements

– Reporting Trigger

– Report Amount

– Report Interval

– Event Threshold

– Logging Interval

– Logging Duration

– Trace Collection Entity IP Address

– Collection period for RRM Measurements LTE (present only if M3 measurement is requested).

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

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

– Measurement Period LTE (if either of the measurements M4, M5 is requested)

– Positioning Method

– MDT PLMN List

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.

The MME receives and stores MDT user consent indication from HSS as part of subscriber information when user context is established in MME at UE attachment. The MME shall consider the MDT user consent information when activating an MDT trace session for the UE. Details on the user consent handling are described in section 4.6.

If positioning method indicates GNSS positioning, eNB should activate the GNSS module of the UE via RRC as specified in TS 36.331 [32]. If positioning method indicates E-Cell ID positioning, the eNB should collect the UE reported UE Rx-Tx time difference measurements as specified in TS 36.331[32] measurement procedures, as well as, any available eNB measured eNB Rx-Tx time difference, Angle of Arrival measurements as specified in TS 36.214 [38] and capture it in MDT trace record.

If Reporting Trigger parameter indicates that all configured RRM measurement trigger should be reported in MDT, then eNodeB should ask the UE to provide the "best effort" location information together with the measurement reporting by setting the includeLocationInfo IE in all RRC measurement reporting configurations.

4.1.2.12.3 Activation of MDT task after UE attachment

Figure 4.1.2.12.2: MDT activation in EPC after UE attachment

The messages propagated to HSS, MME and eNodeB are the same as described in clause 4.1.2.12.2.

When MME can send Trace Start to eNodeB, the following configuration parameters shall be included in the message:

– Area Scope (TA, Cell)

– Trace Reference

– Trace Recording Session Reference

– List of Measurements

– Reporting Trigger

– Report Amount

– Report Interval

– Event Threshold

– Logging Interval

– Logging Duration

– Trace Collection Entity IP Address

– Measurement period LTE (if either of the measurements M4, M5 is requested)

– Positioning Method

– Collection Period for RRM Measurements LTE (present only if M3 measurement is requested)

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

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

– MDT PLMN List.

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.

The MME shall consider the MDT user consent information when activating an MDT trace session for the UE. Detailed procedures about user consent is described in Section 4. 6.1.

In case of logged MDT and the UE is currently being in idle mode, the MME is not required to initiate paging of the UE in order to send the configuration.

Then eNodeB initiates RRC Connection Reconfiguration Request in case of immediate MDT or the IdleMDTConfiguration RRC message in case of logged MDT toward the UE and sends the MDT measurement configuration parameters as received from the MME.

Immediate/Logged signalling based MDT criteria may consist of a cell list. MME shall validate whether the serving cell is controlled by the same eNodeB as any other cell in the cell list. If yes, the MDT activation shall be sent to the serving eNodeB.

4.1.2.12.4 Handling of various scenarios during MDT activation

Handling of various scenarios for Signalling based Logged/Immediate MDT are addressed below:

1) EM initiating MDT activation shall validate that PLMNs specified in the MDT PLMN Listare supported by all the cells specified in the area scope If the eNodeB receives a request where none of the PLMNs in the MDT PLMN List match any PLMN in its list, it shall ignore the request

2) Void.

3) MME shall be informed with a TRACE FAILURE INDICATION message if the eNodeB could not configure the UE because it was in the middle of a handover (refer to TS 36.413[36]). MME shall try to reactivate MDT in the target cell if the target cell scope meets the MDT criteria.

4) Void.

5) When the UE re-enters PLMN (specified in the MDT PLMN List) then the MME shall be responsible for restarting the Immediate MDT activation (if it is as a result of an X2 handover then one option is MME could use the path switch request as trigger). However this is best effort. There can be cases where MME may not be able to restart the MDT when the UE re-enters the PLMN (specified in the MDT PLMN List): for example: If the UE performs intra eNB handover where path switch is not necessarily sent, the MME may not be able to restart MDT

4.1.2.12.5 Activation of Logged MBSFN MDT task before UE attaches to the network

Figure 4.1.2.12.5 shows activation of the Trace Session for MDT job from EPC before the UE attaches to the network.

Figure 4.1.2.12.5: MDT activation procedure in EPC

When HSS activates the trace, for MDT job, to the MME the following configuration parameters shall be included in the message:

– Job Type

– Trace Target: IMSI or IMEISV or IMEI-TAC

– Area Scope (e.g. TA, Cell)

– Trace Reference

– Logging Interval

– Logging Duration

– MDT PLMN List

– MBSFN Area List

NOTE: The conditions are described in clause 5.10 of the present document.

– Trace Collection Entity IP Address

The Specified geographical area field is available when IMSI/IMEI(SV)/IMEI-TAC combined with geographical area are needed for UE selection.

When MME activate MDT activation to eNodeB, the MDT configuration parameters can be included in the message in the Initial Context Setup:

– Area Scope (TA, Cell)

– Trace Reference

– Trace Recording Session Reference

– Logging Interval

– Logging Duration

– Trace Collection Entity IP Address

– MDT PLMN List

– MBSFN Area List

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.

4.1.2.12.6 Activation of Logged MBSFN MDT task after UE attachment

Figure 4.1.2.12.6: Logged MBSFN MDT activation in EPC after UE attachment

The messages propagated to HSS, MME and eNodeB are the same as described in clause 4.1.2.12.2.

When MME can send Trace Start to eNodeB, the following configuration parameters shall be included in the message:

– Area Scope (TA, Cell)

– Trace Reference

– Trace Recording Session Reference

– Logging Interval

– Logging Duration

– Trace Collection Entity IP Address

– MDT PLMN List

– MBSFN Area List (applicable only if the Job Type is Logged MBSFN MDT)

NOTE: The conditions are described in clause 5.10 of the present document.

The MME shall consider the MDT user consent information when activating an MDT trace session for the UE. Detailed procedures about user consent is described in Section 4. 6.1.

In case of Logged MBSFN MDT if the UE is currently being in idle mode, the MME is not required to initiate paging of the UE in order to send the configuration.

If target MBSFN area(s) is configured, UE applies it in addition to other restrictions such as the logging area. The UE will log measurements as long as it receives MBMS service from an indicated target MBSFN area and is within the configured logging area [30].

The configured logging area can span PLMNs in the MDT PLMN List. If no area is configured, the UE will log measurements throughout the PLMNs of the MDT PLM.

4.1.2.13 PS domain activation mechanism for MDT

4.1.2.13.1 General

MDT activation in PS domain extends the trace activation procedure, as described in 4.1.2.5. When a Trace Session is activated, configuration parameters of MDT are added into the Trace Session Activation message(s).

For IMSI/IMEI(SV) based UE selection, or IMSI/IMEI(SV) combined with geographical area based UE selection, UE performance measurements activation request is propagated to UE finally.

Detailed behaviour of the UE when it receives the configuration parameters is described in 3GPP TS 37.320 [30].

In case of Immediate MDT trace (e.g., IMSI/IMEI based selection), the Immediate MDT trace session context of the UE shall be preserved in the network when the UE enters idle mode.

The Logged MDT trace session is preserved in the UE until the duration time of the trace session expires, including also multiple idle periods interrupted by idle-connected-idle state transitions.

The Logged MDT trace session context of the UE is stored in the network as long as the trace session is active, including also the periods when the UE is in connected state.

Two scenarios shall be considered according to UE status when the network activates MDT job: before UE attachment, after UE attachment, different procedures are described in 4.1.2.13.2 and 4.1.2.13.2a.

4.1.2.13.2 Activation of MDT task before UE attaches to the network

The MDT activation procedure is shown in figure 4.1.2.13.2.1.

Figure 4.1.2.13.2.1: MDT activation procedure in PS domain during attach procedure

The Trace Session activation is started from the EMS, when it activates the Trace Session to the HSS. The HSS stores the trace control and configuration parameters in its database.

When a UE registers with the network by sending an ATTACH_REQUEST message to the SGSN, it updates the location information in the HSS by sending the UPDATE_GPRS_LOCATION message to the HSS. The HSS checks if the UE is being traced. If it is being traced, the HSS shall propagate the trace control and configuration parameters to the SGSN by sending a MAP-ACTIVATE_TRACE_MODE – see 3GPP TS 29.002 [11] message to the SGSN (This message can be embedded also in the MAP INSERT SUBSCRIBER DATA message). The SGSN receives and stores MDT user consent indication from HSS as part of subscriber information when user context is established in SGSN at UE attachment (details are available in clause 4. 6.1). When an inter-SGSN routing area update occurs, HSS shall send the MAP-ACTIVATE_TRACE_MODE message to the new SGSN. The Trace Session Activation from HSS to SGSN shall contain the following MDT specific parameters in addition to the existing trace parameters:

– Job Type.

– Area Scope.

– List of Measurements.

– Reporting Trigger.

– Report Interval.

– Report Amount.

– Event Threshold.

– Logging Interval..

– Logging Duration.

– Trace Collection Entity IP Address.

– Measurement Quantity.

– Measurement Period UMTS (if either of the measurements M6, M7 is requested).

– Collection Period for RRM Measurements UMTS (present only if any of M4 or M5 measurements are requested).

– Event Threshold for UE Power Headroom Measurement UMTS (present only if event triggered reporting for M4 measurement is requested).

– Positioning Method.

– MDT PLMN List.

Note that at the same time not all of the parameters can be present. The condition which parameters shall be present is described in clause 5 of the present document.

When SGSN receives the MAP-ACTIVATE_TRACE_MODE message it shall store the trace control and configuration parameters and shall start a Trace Session and shall send the CN_INVOKE_TRACE message to the RNC. The SGSN shall consider the MDT user consent information when activating an MDT trace session for the UE. The SGSN shall send the following parameters to the RNC beside the existing trace parameters:

– Job Type.

– Area Scope.

– List of Measurements.

– Reporting Trigger.

– Report Interval.

– Report Amount.

– Event Threshold.

– Logging Interval.

– Logging Duration.

– Trace Collection Entity IP Address.

– Measurement Quantity.

– Measurement Period UMTS (if either of the measurements M6, M7 is requested).

– Collection Period for RRM Measurements UMTS (present only if any of M4 or M5 measurements are requested).

– Event Threshold for UE Power Headroom Measurement UMTS (present only if event triggered reporting for M4 measurement is requested).

– Positioning Method.

– MDT PLMN List.

Note that at the same time not all of the parameters can be present. The conditions which parameters shall be present is described in clause 5 of the present document.

4.1.2.13.2a Activation of MDT task after UE attaches to the network

The MDT activation procedure after UE attaches to the network is shown in figure 4.1.2.13.2a.1.

HSS

EMS

SGSN

RNC

Attach Request

Update GPRS location

Trace activation (MDT configuration)

Starting Trace Control and Configuration

Activate Trace Mode (MDT configuration)

Storing Trace Control and Configuration parameters (incl. MDT parameters)

CN invoke Trace

Trace Control and Con- figuration parameters (incl. MDT parameters)

RRC connection reconfiguration (MDT configuration)

MDT data collection

Figure 4.1.2.13.2a.1 MDT activation procedure in PS domain after UE attachs to the network

When a UE registers with the network by sending an ATTACH_REQUEST message to the SGSN, it updates the location information in the HSS by sending the UPDATE_GPRS_LOCATION message to the HSS.

The Trace Session activation is started from the EMS, when it activates the Trace Session to the HSS. When the HSS send trace activation to the SGSN, the HSS shall propagate the trace control and configuration parameters to the SGSN by sending a MAP-ACTIVATE_TRACE_MODE – see 3GPP TS 29.002 [11] message to the SGSN (This message can be embedded also in the MAP INSERT SUBSCRIBER DATA message). The SGSN receives and stores MDT user consent indication from HSS as a part of subscriber information (details are available in Section 4. 6.1). When an inter-SGSN routing area update occurs, HSS shall send the MAP-ACTIVATE_TRACE_MODE message to the new SGSN. The Trace Session Activation from HSS to SGSN shall contain the following MDT specific parameters in addition to the existing trace parameters:

– Job Type.

– Area Scope.

– List of Measurements.

– Reporting Trigger.

– Report Interval.

– Report Amount.

– Event Threshold.

– Logging Interval.

– Logging Duration.

– Trace Collection Entity IP Address.

– Measurement Quantity.

– Measurement Period UMTS (if either of the measurements M6, M7 is requested).

– Collection Period for RRM Measurements UMTS (present only if any of M4 or M5 measurements are requested).

– Event Threshold for UE Power Headroom Measurement UMTS (present only if event triggered reporting for M4 measurement is requested).

– Positioning Method.

– MDT PLMN List.

Note that at the same time not all of the parameters can be present. The condition which parameters shall be present is described in clause 5 of the present document.

– Job Type.

– Area Scope.

– List of Measurements.

– Reporting Trigger.

– Report Interval.

– Report Amount.

– Event Threshold.

– Logging Interval.

– Logging Duration.

– Trace Collection Entity IP Address.

– Measurement Quantity.

– Measurement Period UMTS (if either of the measurements M6, M7 is requested).

– Collection Period for RRM Measurements UMTS (present only if any of M4 or M5 measurements are requested).

– Event Threshold for UE Power Headroom Measurement UMTS (present only if event triggered reporting for M4 measurement is requested).

– Positioning Method.

– MDT PLMN List.

Note that at the same time not all of the parameters can be present. The conditions which parameters shall be present is described in clause 5 of the present document.

4.1.2.13.3 Handling of various scenarios during MDT activation

Handling of various scenarios for Signalling based Logged/Immediate MDT is addressed below:

1) EM initiating MDT activation shall validate that the MCC and MNC specified in the Trace Reference is the same as the PLMN supported by all the RNCs specified in the area scope. If the RNC receives a request with a PLMN in the TraceReference that does not match any PLMN in its list, it shall ignore the request.

2) SGSN shall trigger the MDT activation only when the MDT area criterion is satisfied. But if the RNC receives a request that is outside the area scope then the RNC shall store the MDT configuration and forward the request when a handover occurs (intra PLMN).

3) When the UE re-enters the PLMN (in Trace Reference) which matches the area scope defined in the MDT configuration then the SGSN shall be responsible for restarting the Immediate MDT activation. However, this is best effort.

4) Void.

5) SGSN shall re-initiate CN Invoke Trace procedure to reactivate MDT job after successful SRNS relocation if the RNC could not configure the UE since it was in the middle of inter-RNC handover (refer to TS 25.413 [13]). SGSN shall try to reactivate MDT in the target cell if the target cell scope meets the MDT criteria.

6) Void.

7) Management based MDT criteria may consist of a cell list. SGSN shall validate whether the UE is controlled by the same RNC as any other cell in the cell list. If yes, the MDT activation shall be sent to the serving RNC. If the RNC receives a Signalling Based MDT activation request when the UE is served by a cell that is in the RNC but not in the MDT area scope then the RNC shall store the MDT configuration and configure the UE when the UE moves to a cell in the RNC (intra RNC handover) that satisfies the area scope in the request.

4.1.2.14 CS domain activation mechanism for MDT

4.1.2.14.0 Activation of MDT task before UE attaches to the network

In UMTS it is also possible to send the MDT job activation via the CS domain instead of the PS domain. The activation mechanism is shown in figure 4.1.2.14.1.

Figure 4.1.2.14.1: MDT activation procedure in CS domain during attach procedure

The Trace Session activation is started from the EMS, when it activates the Trace Session to the HSS. The HSS stores the trace control and configuration parameters in its database.

When a UE registers with the network by sending an ATTACH_REQUEST message to the MSC Server, it updates the location information in the HSS by sending the UPDATE_LOCATION message to the HSS. The HSS checks if the UE is being traced. If it is being traced, the HSS shall propagate the trace control and configuration parameters to the MSC Server by sending a MAP-ACTIVATE_TRACE_MODE – see 3GPP TS 29.002 [11] message to the MSC Server (This message can be embedded also in the MAP INSERT SUBSCRIBER DATA message). The MSC Server receives and stores MDT user consent indication from HSS as part of subscriber information at UE attachment (details are available in Section 4.2.8.1). When an inter-VLR Location Area update occurs, HSS shall send the MAP-ACTIVATE_TRACE_MODE message to the new VLR / MSC Server. The Trace Session Activation from HSS to MSC Server shall contain the following MDT specific parameters in addition to the existing trace parameters:

– Job Type

– Area Scope

– List of Measurements

– Reporting Trigger

– Report Interval

– Report Amount

– Event Threshold

– Logging Interval

– Logging Duration

– Trace Collection Entity IP Address

– Measurement Quantity

– Measurement Period UMTS (if either of the measurements M6, M7 is requested)

– Collection Period for RRM Measurements UMTS (present only if any of M4 or M5 measurements are requested).

– Event Threshold for UE Power Headroom Measurement UMTS (present only if event triggered reporting for M4 measurement is requested)

– Positioning Method

– MDT PLMN List

Note that at the same time not all of the parameters can be present. The condition under which parameters shall be present is described in clause 5 of the present document.

When MSC Server receives the MAP-ACTIVATE_TRACE_MODE message it shall store the trace control and configuration parameters and shall start a Trace Session and shall send the CN_INVOKE_TRACE message to the RNC. The MSC Server shall consider the MDT user consent information when activating an MDT trace session for the UE. The MSC Server shall send the following parameters to the RNC beside the existing trace parameters:

– Job Type.

– Area Scope.

– List of Measurements.

– Reporting Trigger.

– Report Interval.

– Report Amount.

– Event Threshold.

– Logging Interval.

– Logging Duration.

– Trace Collection Entity IP Address.

– Measurement Quantity.

– Measurement Period UMTS (if either of the measurements M6, M7 is requested).

– Collection Period for RRM Measurements UMTS (present only if any of M4 or M5 measurements are requested).

– Event Threshold for UE Power Headroom Measurement UMTS (present only if event triggered reporting for M4 measurement is requested).

– Positioning Method.

– MDT PLMN List.

Note that at the same time not all of the parameters can be present. The condition under which parameters shall be present is described in clause 5 of the present document.

In case of Immediate MDT trace (e.g., IMSI/IMEI based selection), the Immediate MDT trace session context of the UE shall be preserved in the network when the UE enters idle mode.

The Logged MDT trace session is preserved in the UE until the duration time of the trace session expires, including also multiple idle periods interrupted by idle-connected-idle state transitions.

The Logged MDT trace session context of the UE is stored in the network as long as the trace session is active, including also the periods when the UE is in connected state.

4.1.2.14.1 MDT Error Handling

Handling of various scenarios for Signalling based Logged/Immediate MDT is addressed below:

1) EM initiating MDT activation shall validate that the MCC and MNC specified in the Trace Reference is the same as the PLMN supported by all the cells specified in the area scope. If the RNC receives a request with a PLMN in the TraceReference that does not match any PLMN in its list , it shall ignore the request

2) MSC-S shall trigger the activation only when the MDT area criterion is satisfied. But if for some reason the RNC receives a request that is outside the area scope then the RNC shall store the MDT configuration and forward the request when a handover occurs (intra PLMN).

3) When the UE re-enters the PLMN (in Trace Reference) which matches the area scope defined in the MDT configuration then the MSC shall be responsible for restarting the Immediate MDT activation. However this is best effort.

4) Void.

5) MSC-S shall re-initiate CN Invoke Trace procedure to reactivate MDT job after SRNS relocation (refer to TS 25.413 [13]) if the RNC could not configure the UE since it was in the middle of inter RNC handover. MSC-S shall try to reactivate MDT in the target cell if the target cell scope meets the MDT criteria.

6) Void.

7) Management based MDT criteria may consist of a cell list. MSC-S shall validate whether the UE is controlled by the same RNC as any other cell in the cell list. If yes, the MDT activation shall be sent to the serving RNC. If the RNC receives a Signalling Based MDT activation request when the UE is served by a cell that is in the RNC but not in the MDT area scope then the RNC shall store the MDT configuration and configure the UE when the UE moves to a cell in the RNC (intra RNC handover) that satisfies the area scope in the request

4.1.2.15 5GC activation mechanism

4.1.2.15.1 UE attached to 5GC via NG-RAN

Figure 4.1.2.15.1.1 illustrates the signaling Trace Session activation procedure in 5GC as part of the Registration procedure:

Figure 4.1.2.15.1.1: Trace activation in 5GC following the Registration procedure

The steps 3-6, 12 and 15 below are parts of the General Registration procedure – see 3GPP TS 23.502 [41] clause 4.2.2.2 for specific details. Present document does not attempt to re-define how General Registration procedure works, but rather illustrates the signaling Trace Activation aspects.

1. Management system activates Trace Session to the UDM. The following trace control and configuration parameters shall be included in the Trace Activation message:

– Trace Target: SUPI or IMEISV.

– Trace Reference.

– Triggering Events for AMF, SMF, UPF and PCF.

– Trace Depth.

– List of NE Types to trace.

– List of Interfaces for AMF, SMF, UPF, PCF and NG-RAN.

– Trace Collection Entity IP Address for the file-based trace reporting or Trace Reporting Consumer URI for the streaming trace reporting.

2. UDM stores the trace control and configuration parameters received from the management system.

3. UE sends Registration request to NG-RAN node.

4. NG-RAN node selects appropriate AMF.

5. NG-RAN node forwards the UE Registration request to the selected AMF.

6. AMF receives the trace control and configuration parameters information from UDM via Nudm_SDM_Get operation (see step 14 in clause 4.2.2.2.2 and clause 5.2.3.3 of 3GPP TS 23.502 [41]).

7. AMF stores the trace control and configuration parameters received from the UDM.

8. AMF starts the Trace Session according to the received configuration.

9. AMF sends the Start Trace message over NG interface (N2 interface from the 5GC perspective)

10. NG-RAN node stores the trace control and configuration parameters received from the AMF. This step is part of NG-RAN signaling trace activation – see clause 4.1.2.16 for more details.

11. NG-RAN node starts the Trace Session according to the received configuration. This step is part of NG-RAN signaling trace activation – see clause 4.1.2.16 for more details.

12. AMF establishes Policy Association with PCF (see step 16 in clause 4.2.2.2.2 of 3GPP TS 23.502 [41]) and provides the trace control and configuration parameters information to the PCF.

13. PCF stores the trace control and configuration parameters received from the AMF as part of Policy Association.

14. PCF starts the Trace Session according to the received configuration.

15. AMF provides the trace control and configuration parameters information to the SMF as part of the SM Context (see step 18 in clause 4.2.2.2.2 of 3GPP TS 23.502 [41]).

16. SMF stores the trace control and configuration parameters received from the AMF.

17. SMF starts the Trace Session according to the received configuration.

Figure 4.1.2.15.1.2 illustrates the signaling Trace Session activation procedure in 5GC as part of the PDU Session Establishment procedure for the UE that has already been registered:

Figure 4.1.2.15.1.2: Trace activation in 5GC following the PDU Session Establishment procedure

The steps 6, 10, 11, 14 and 15 below are parts of the UE Requested PDU Session Establishment procedure – see 3GPP TS 23.502 [41] clause 4.3.2.2 for specific details. Present document does not attempt to re-define how UE Requested PDU Session Establishment procedure works, but rather illustrates the signaling Trace Activation aspects.

1. Management system activates Trace Session to the UDM. The following trace control and configuration parameters shall be included in the Trace Activation message:

– Trace Target: SUPI or IMEISV.

– Trace Reference.

– Triggering Events for AMF, SMF, UPF and PCF.

– Trace Depth.

– List of NE Types to trace.

– List of Interfaces for AMF, SMF, PCF, UPF and NG-RAN.

– Trace Collection Entity IP Address for the file-based trace reporting or Trace Reporting Consumer URI for the streaming trace reporting.

2. UDM stores the trace control and configuration parameters received from the management system.

3. UDM sends Nudm_SDM_Notification to AMF with the trace control and configuration parameters information (see clauses 4.5.1 and 5.2.3.3 of 3GPP TS 23.502 [41]).

4. AMF stores the trace control and configuration parameters received from the UDM.

5. AMF starts the Trace Session according to the received configuration.

6. UE sends PDU Session Establishment request to AMF

7. AMF sends the Start Trace message over NG interface (N2 interface from the 5GC perspective)

8. NG-RAN node stores the trace control and configuration parameters received from the AMF. This step is part of NG-RAN signaling trace activation – see clause 4.1.2.16 for more details.

9. NG-RAN node starts the Trace Session according to the received configuration. This step is part of NG-RAN signaling trace activation – see clause 4.1.2.16 for more details.

10. AMF selects an appropriate SMF

11. AMF sends the Nsmf_PDUSession_CreateSMContext request to the selected SMF with the trace control and configuration parameters.

12. SMF stores the trace control and configuration parameters received from the AMF.

13. SMF starts the Trace Session according to the received configuration.

14. SMF selects an approprite PCF

15. SMF establishes Session Management Policy Association with PCF (see step 7 in clause 4.3.2.2.1 of 3GPP TS 23.502 [x5]) and provides the trace control and configuration parameters information to the PCF.

16. PCF stores the trace control and configuration parameters received from the SMF as part of Policy Association.

17. PCF starts the Trace Session according to the received configuration.

18. SMF selects an approprite UPF

19. SMF performs N4 Session Establishment with UPF (see step 10 in clause 4.3.2.2.1 of 3GPP TS 23.502 [41]) and provides the trace control and configuration parameters information to the UPF.

20. UPF stores the trace control and configuration parameters received from the SMF as part of N4 Session Establishment.

21. UPF starts the Trace Session according to the received configuration.

Figure 4.1.2.15.1.3 illustrates the signaling Trace Session activation procedure in 5GC as part of the PDU Session Establishment procedure for the UE that has already been registered where SMF obtains trace control and configuration parameters from UDM via Nudm_UECM_Registration procedure:

Figure 4.1.2.15.1.3: Trace activation in 5GC following the PDU Session Establishment procedure

1. Management system activates Trace Session to the UDM. The following trace control and configuration parameters shall be included in the Trace Activation message:

– Trace Target: SUPI or IMEISV

– Trace Reference

– Triggering Events for AMF, SMF, UPF and PCF

– Trace Depth

– List of NE Types to trace

– List of Interfaces for AMF, SMF, UPF, PCF and NG-RAN

– Trace Collection Entity IP Address for the file-based trace reporting or Trace Reporting Consumer URI the streaming trace reporting

2. UDM stores the trace control and configuration parameters received from the management system.

3. UDM sends Nudm_SDM_Notification to AMF with the trace control and configuration parameters information (see clauses 4.5.1 and 5.2.3.3 of 3GPP TS 23.502 [41]).

4. AMF stores the trace control and configuration parameters received from the UDM.

5. AMF starts the Trace Session according to the received configuration.

6. UE sends PDU Session Establishment request to AMF

7. AMF sends the Start Trace message over NG interface (N2 interface from the 5GC perspective)

8. NG-RAN node stores the trace control and configuration parameters received from the AMF. This step is part of NG-RAN signaling trace activation – see clause 4.1.2.16 for more details.

9. NG-RAN node starts the Trace Session according to the received configuration. This step is part of NG-RAN signaling trace activation – see clause 4.1.2.16 for more details.

10. AMF selects an appropriate SMF

11. AMF sends the Nsmf_PDUSession_CreateSMContext request to the selected SMF

12. SMF performs NuDM_UECM_Registration procedure with UDM and receives the trace control and configuration parameters from UDM

13. SMF stores the trace control and configuration parameters received from the UDM.

14. SMF starts the Trace Session according to the received configuration.

15. SMF selects an approprite PCF

16. SMF establishes Session Management Policy Association with PCF (see step 7 in clause 4.3.2.2.1 of 3GPP TS 23.502 [41]) and provides the trace control and configuration parameters information to the PCF.

17. PCF stores the trace control and configuration parameters received from the SMF as part of Policy Association.

18. PCF starts the Trace Session according to the received configuration.

19. SMF selects an approprite UPF

20. SMF performs N4 Session Establishment with UPF (see step 10 in clause 4.3.2.2.1 of 3GPP TS 23.502 [41]) and provides the trace control and configuration parameters information to the UPF.

21. UPF stores the trace control and configuration parameters received from the SMF as part of N4 Session Establishment.

22. UPF starts the Trace Session according to the received configuration.

Note: The specific scenarios where SMF receives trace control and configuration parameters either from UDM or from AMF are specified in 3GPP TS 23.502 [41].

Figure 4.1.2.15.1.4 illustrates the signaling Trace Session activation procedure in 5GC as part of the PDU Session Modification procedure for the UE that has already been registered and has an on-going PDU Session:

Figure 4.1.2.15.1.4: Trace activation in 5GC following the PDU Session Modification procedure

The steps 6 and 9 below are parts of the PDU Session Modification procedure – see 3GPP TS 23.502 [41] clause 4.3.3.2 for specific details. Present document does not attempt to re-define how PDU Session Modification procedure works, but rather illustrates the signaling Trace Activation aspects.

1. Management system activates Trace Session to the UDM. The following trace control and configuration parameters shall be included in the Trace Activation message:

– Trace Target:SUPI or IMEISV.

– Trace Reference.

– Triggering Events for AMF, SMF, UPF and PCF.

– Trace Depth.

– List of NE Types to trace.

– List of Interfaces for AMF, SMF, UPF, PCF and NG-RAN.

– Trace Collection Entity IP Address for the file-based trace reporting or Trace Reporting Consumer URI for the streaming trace reporting.

2. UDM stores the trace control and configuration parameters received from the management system.

3. UDM sends Nudm_SDM_Notification to AMF with the trace control and configuration parameters information (see clauses 4.5.1 and 5.2.3.3 of 3GPP TS 23.502 [41]).

4. AMF stores the trace control and configuration parameters received in step 9.

5. AMF starts the Trace Session according to the received configuration.

6. AMF sends Nsmf_PDUSession_UpdateSMContext request with the trace control and configuration parameters information to the SMF

7. SMF stores the trace control and configuration parameters received from the UDM.

8. SMF starts the Trace Session according to the received configuration.

9. SMF performs Session Management Policy Modification with PCF (see step 7 in clause 4.3.3.2 of 3GPP TS 23.502 [41]) and provides the trace control and configuration parameters information to the PCF.

10. PCF stores the trace control and configuration parameters received from the SMF as part of Policy Association.

11. PCF starts the Trace Session according to the received configuration.

12. SMF performs N4 Session Modification with UPF (see step 10 in clause 4.3.2.2.1 of 3GPP TS 23.502 [41]) and provides the trace control and configuration parameters information to the UPF.

13. UPF stores the trace control and configuration parameters received from the SMF as part of N4 Session Modification.

14. UPF starts the Trace Session according to the received configuration.

15. AMF sends the Start Trace message over NG interface (N2 interface from the 5GC perspective)

16. NG-RAN node stores the trace control and configuration parameters received from the AMF. This step is part of NG-RAN signaling trace activation – see clause 4.1.2.16 for more details.

17. NG-RAN node starts the Trace Session according to the received configuration. This step is part of NG-RAN signaling trace activation – see clause 4.1.2.16 for more details.

Figure 4.1.2.15.1.5 illustrates the signaling Trace Session activation procedure in 5GC as part of the PDU Session Modification procedure for the UE that has already been registered and has an on-going PDU Session where UDM notifies SMF about trace activation directly:

Figure 4.1.2.15.1.5: Trace activation in 5GC following the PDU Session Modification procedure (with UDM to SMF notification)

1. Management system activates Trace Session to the UDM. The following trace control and configuration parameters shall be included in the Trace Activation message:

– Trace Target: SUPI or IMEISV.

– Trace Reference.

– Triggering Events for AMF, SMF, UPF and PCF.

– Trace Depth.

– List of NE Types to trace.

– List of Interfaces for AMF, SMF, UPF, PCF and NG-RAN.

– Trace Collection Entity IP Address for the file-based trace reporting or Trace Reporting Consumer URI for the streaming trace reporting.

2. UDM stores the trace control and configuration parameters received from the management system.

3. UDM sends Nudm_SDM_Notification to AMF with the trace control and configuration parameters information (see clauses 4.5.1 and 5.2.3.3 of 3GPP TS 23.502 [41]).

4. AMF stores the trace control and configuration parameters received in step 9.

5. AMF starts the Trace Session according to the received configuration.

6. UDM sends Nudm_SDM_Notification to SMF with the trace control and configuration parameters information (see clauses 4.5.2 and 5.2.3.3 of 3GPP TS 23.502 [41]).