Method, apparatus and computer program

Abstract

A method comprising: receiving, at a base station (e.g. a gNB) from a network entity (e.g. a core network (CN) node, a management system (OAM) or network data analytics function (NWDAF), one or more m

Description

FIELD

[0001] The present application relates to an apparatus, method and computer program. In particular, but not exclusively, the present application relates to Minimization of Drive Tests (MDT). BACKGROUND

[0002] A communication system can be seen as a facility that enables communication sessions between two or more entities such as user terminals, base stations and / or other nodes by providing carriers between the various entities involved in the communications path. A communication system can be provided for example by means of a communication network and one or more compatible communication devices. The communication sessions may comprise, for example, communication of data for carrying communications such as voice, video, electronic mail (email), text message, multimedia and / or content data and so on. Non-limiting examples of services provided comprise two-way or multi-way calls, data communication or multimedia services and access to a data network system, such as the Internet.

[0003] The communication system and associated devices typically operate in accordance with a given standard or specification which sets out what the various entities associated with the system are permitted to do and how that should be achieved. Communication protocols and / or parameters which shall be used for the connection are also typically defined. One example of a communications system is UTRAN (3G radio). Other examples of communication systems are the long-term evolution (LTE) of the Universal Mobile Telecommunications System (UMTS) radio-access technology and so-called 5G or New Radio (NR) networks. NR is being standardized by the 3rd Generation Partnership Project (3GPP). SUMMARY

[0004] According to a first aspect there is provided an apparatus comprising: means for receiving, from a network entity, one or more minimization of drive test, MDT, measurement configurations comprising at least one trace reference; means for selecting a user equipment based on the one or more MDT measurement configurations, wherein an MDT measurement configuration of the one or more MDT measurement configurations is to be applied to the selected user equipment in an MDT session identified by a trace reference of the at least one trace reference and a trace recording session reference; means for sending, to a core network node, the MDT measurement configuration of the one or more MDT measurement configurations, an identifier of the selected user equipment, the trace reference and the trace recording session reference.

[0005] According to some examples, the apparatus comprises means for receiving the MDT measurement configuration from the core network node.

[0006] According to some examples, the MDT measurement configuration is received via an initial context setup request message.

[0007] According to some examples, the network entity comprises a management system or a Network Data Analytics Function.

[0008] According to some examples, apparatus means for sending at least one MDT record from the MDT session of the user equipment to a Trace Collection Entity.

[0009] According to some examples, the MDT measurement configuration comprises duration information for the MDT session.

[0010] According to some examples, the apparatus comprises means for allocating the trace recording session reference to the MDT session.

[0011] According to some examples, the one or more MDT measurement configurations further include at least one area indication, wherein the user equipment is selected based on the one or more MDT measurement configurations and the at least one area indication.

[0012] According to a second aspect, there is provided an apparatus comprising at least one processor and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to perform: receiving, from a network entity, one or more minimization of drive test, MDT, measurement configurations comprising at least one trace reference; selecting a user equipment based on the one or more MDT measurement configurations, wherein an MDT measurement configuration of the one or more MDT measurement configurations is to be applied to the selected user equipment in an MDT session identified by a trace reference of the at least one trace reference and a trace recording session reference; sending, to a core network node, the MDT measurement configuration of the one or more MDT measurement configurations, an identifier of the selected user equipment, the trace reference and the trace recording session reference.

[0013] According to some examples, the apparatus comprises means for receiving the MDT measurement configuration from the core network node.

[0014] According to some examples, the MDT measurement configuration is received via an initial context setup request message.

[0015] According to some examples, the network entity comprises a management system or a Network Data Analytics Function.

[0016] According to some examples, the at least one processor and at least one memory storing instructions cause, when executed by the at least one processor, the apparatus at least to perform sending at least one MDT record from the MDT session of the user equipment to a Trace Collection Entity.

[0017] According to some examples, the MDT measurement configuration comprises duration information for the MDT session.

[0018] According to some examples, the at least one processor and at least one memory storing instructions cause, when executed by the at least one processor, the apparatus at least to perform allocating the trace recording session reference to the MDT session.

[0019] According to some examples, the one or more MDT measurement configurations further include at least one area indication, wherein the user equipment is selected based on the one or more MDT measurement configurations and the at least one area indication.

[0020] According to a third aspect there is provided a method comprising: receiving, from a network entity, one or more minimization of drive test, MDT, measurement configurations comprising at least one trace reference; selecting a user equipment based on the one or more MDT measurement configurations, wherein an MDT measurement configuration of the one or more MDT measurement configurations is to be applied to the selected user equipment in an MDT session identified by a trace reference of the at least one trace reference and a trace recording session reference; sending, to a core network node, the MDT measurement configuration for the MDT session of the one or more MDT measurement configurations, an identifier of the selected user equipment, the trace reference and the trace recording session reference.

[0021] According to some examples, the method comprises receiving the MDT measurement configuration from the core network node.

[0022] According to some examples, the MDT measurement configuration is received via an initial context setup request message.

[0023] According to some examples, the network entity comprises a management system or a Network Data Analytics Function.

[0024] According to some examples, the method comprises sending at least one MDT record from the MDT session of the user equipment to a Trace Collection Entity.

[0025] According to a fourth aspect there is provided a computer readable medium comprising instructions which, when executed by an apparatus, cause the apparatus to perform at least the following: receiving, from a network entity, one or more minimization of drive test, MDT, measurement configurations comprising at least one trace reference; selecting a user equipment based on the one or more MDT measurement configurations, wherein an MDT measurement configuration of the one or more MDT measurement configurations is to be applied to the selected user equipment in an MDT session identified by a trace reference of the at least one trace reference and a trace recording session reference; sending, to a core network node, the MDT measurement configuration for the MDT session of the one or more MDT measurement configurations, an identifier of the selected user equipment, the trace reference and the trace recording session reference.

[0026] According to a fifth aspect, there is provided a non-transitory computer readable medium comprising program instructions that, when executed by an apparatus, cause the apparatus to perform at least the following: receiving, from a network entity, one or more minimization of drive test, MDT, measurement configurations comprising at least one trace reference; selecting a user equipment based on the one or more MDT measurement configurations, wherein an MDT measurement configuration of the one or more MDT measurement configurations is to be applied to the selected user equipment in an MDT session identified by a trace reference of the at least one trace reference and a trace recording session reference; sending, to a core network node, the MDT measurement configuration for the MDT session of the one or more MDT measurement configurations, an identifier of the selected user equipment, the trace reference and the trace recording session reference.

[0027] According to a sixth aspect there is provided an apparatus comprising: means for receiving, from a first base station node, an MDT measurement configuration for a user equipment, an identifier of the user equipment, a trace reference and a trace recording session reference; wherein the MDT measurement configuration is applied to the user equipment in an MDT session identified by the trace reference and the trace recording session reference.

[0028] According to some examples, the apparatus comprises means for sending the MDT measurement configuration to a second base station node.

[0029] According to some examples, the first base station node and the second base station node are different base station nodes.

[0030] According to some examples, the first base station node and the second base station node are the same base station node.

[0031] According to some examples, the MDT measurement configuration comprises duration information of the MDT session.

[0032] According to a seventh aspect there is provided an apparatus comprising at least one processor and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to perform: receiving, from a first base station node, an MDT measurement configuration for a user equipment, an identifier of the user equipment, a trace reference and a trace recording session reference; wherein the MDT measurement configuration is applied to the user equipment in an MDT session identified by the trace reference and the trace recording session reference.

[0033] According to some examples, the at least one processor and at least one memory storing instructions cause, when executed by the at least one processor, the apparatus at least to perform sending the MDT measurement configuration to a second base station node.

[0034] According to some examples, the apparatus comprises means for sending the MDT measurement configuration to a second base station node.

[0035] According to some examples, the first base station node and the second base station node are different base station nodes.

[0036] According to some examples, the first base station node and the second base station node are the same base station node.

[0037] According to some examples, the MDT measurement configuration comprises duration information of the MDT session.

[0038] According to an eighth aspect there is provided a method comprising receiving, from a first base station node, an MDT measurement configuration for a user equipment, an identifier of the user equipment, a trace reference and a trace recording session reference; wherein the MDT measurement configuration is applied to the user equipment in an MDT session identified by the trace reference and the trace recording session reference.

[0039] According to some examples, the method comprises sending the MDT measurement configuration to a second base station node.

[0040] According to some examples, the first base station node and the second base station node are different base station nodes.

[0041] According to some examples, the first base station node and the second base station node are the same base station node.

[0042] According to some examples, the MDT measurement configuration comprises duration information of the MDT session.

[0043] According to a ninth aspect there is provided a computer readable medium comprising instructions which, when executed by an apparatus, cause the apparatus to perform at least the following: receiving, from a first base station node, an MDT measurement configuration for a user equipment, an identifier of the user equipment, a trace reference and a trace recording session reference; wherein the MDT measurement configuration is applied to the user equipment in an MDT session identified by the trace reference and the trace recording session reference.

[0044] According to a tenth aspect there is provided a non-transitory computer readable medium comprising program instructions that, when executed by an apparatus, cause the apparatus to perform at least the following: receiving, from a first base station node, an MDT measurement configuration for a user equipment, an identifier of the user equipment, a trace reference and a trace recording session reference; wherein the MDT measurement configuration is applied to the user equipment in an MDT session identified by the trace reference and the trace recording session reference. DESCRIPTION OF FIGURES

[0045] Embodiments will now be described, by way of example only, with reference to the accompanying Figures in which:

[0046] Figure 1 shows an example functional framework for Artificial Intelligence / Machine Learning (AI / ML) in Radio Access Network (RAN);

[0047] Figure 2 shows an example message flow for activating MDT measurements;

[0048] Figure 3 shows an example message flow for activating continuous MDT measurements;

[0049] Figure 4 shows an example method flow;

[0050] Figure 5 shows an example method flow;

[0051] Figure 6 shows a representation of a control apparatus according to some example embodiments;

[0052] Figure 7 shows a representation of an apparatus according to some example embodiments; and

[0053] Figure 8 shows a schematic representation of a non-volatile memory medium storing instructions which when executed by a processor allow a processor to perform one or more of the steps of the methods disclosed herein. DETAILED DESCRIPTION

[0054] The present disclosure relates to MDT configuration in a communications system.

[0055] MDT measurements can be used to determine information about a communications system. Examples herein provide a method for consistently providing an MDT measurement configuration to a User Equipment (UE), which improves accuracy of information determined from the UE’s MDT records.

[0056] Artificial Intelligence (Al) / Machine Learning (ML) can be enabled in RAN. Enhancements in data collection can be used to enable AI / ML techniques to provide predictions beneficial for e.g., network energy saving, load balancing and / or mobility optimization, to give a few examples.

[0057] Figure 1 shows an example of a functional framework of how AI / ML can be incorporated in a RAN. Note that this is an example and different implementations may have different variations of the functional framework e.g., in that the Actor and the Model Inference may be collapsed in a single entity, Model Performance feedback may be optional or even non-existent, to give some examples. Data is collected at 100 from the RAN. This data can be used as training data for model training performed at 106. The data collected at 100 can also be used as inference data input into trained models used to determine output data.

[0058] Data Collection function 100 may comprise a function for providing input data to model training functions (e.g., function 106) and model inference functions (e.g., function 102). Examples of input data may include measurements from network entities, UE(s), actor feedback, output from AI / ML model(s), etc. Data collection 100 may provide training Data for input to AI / ML Model Training function 106. Data collection may provide input inference data for the AI / ML Model Inference function 102.

[0059] Model training function 106 may perform AI / ML model training and / or validation. AI / ML model testing may also use model performance metrics. Data preparation of data provided by data collection function 100 may also be performed by the model training function 106 (e.g., data pre-processing and cleaning, formatting, and transformation). Model training function 106 may deploy / update ML models to model inference function 102. These deployed / updated models may be validated, trained and / or tested by model training function 106.

[0060] Model inference function 102 may provide AI / ML model inference output (e.g., predictions, decisions, etc.). Model inference function 102 may provide model performance feedback to model training function 106.

[0061] Actor function 104 may comprise a function that receives output from model inference function 102 and trigger / perform one or more corresponding action(s). Actor 104 may trigger actions for other entities and / or may perform actions itself. Actor 104 may feedback information for deriving training data, inference data or for monitoring AI / ML model performance.

[0062] The model trained at 106 may be deployed to be used as an inference model at 102. The model may be updated during subsequent training steps. The model inference at 102 may also be used to provide model performance feedback for model training at 106. The output from the model inference at 102 may be provided to an actor 104, who in turn may provide feedback for data collection at 100.

[0063] The MDT (Minimization of Drive Tests) feature is used by operators who want feedback on the coverage on a particular area of their network (Management-based MDT) or feedback on the radio conditions experienced by some specific UE(s) in a given coverage area of a Public Land Mobile Network (PLMN) (signalling based MDT). This can be used for data collection at 100 of Figure 1, as well as for other purposes.

[0064] 3GPP has defined two types of MDT, Logged MDT and Immediate MDT. Logged MDT applies for idle states of a UE e.g., RRCJDLE and inactive states of a UE e.g., RRC_INACTIVE modes. For logged MDT, the UE may receive a logged MDT configuration from the network when the UE is in a connected state e.g., RRC_CONNECTED. The logged MDT configuration may be stored in the UE. The configured logged MDT measurements are performed when the UE is in an RRCJDLE state or an RRCJNACTIVE state during the configured logging duration, and measurement results are then buffered in the UE. When the UE reconnects to a network, the availability of buffered measurements is signalled to the network. The network may then retrieve the log and forward to the Operations, Administration and Management (0AM) system of the network (e.g., Trace Collection Entity - TCE). In a connected state (e.g., RRC_CONNECTED mode) the logged MDT configuration is kept but the measurements are not performed, however the network may be configured with an Immediate MDT configuration to use. The latter may result the UE to be configured with RRC measurements, however the UE is not aware whether the purpose of these RRC measurements are Radio Resource Management (RRM) or MDT.

[0065] Continuous MDT collection is defined as MDT data collection that enables to collect data from the same UE across RRC states (RRC_CONNECTED, RRCJDLE, RRC_INACTIVE). Continuous MDT may have benefits in the data collection by facilitating data preparation and by avoiding errors in the data collection. Continuous MDT may comprise logged MDT and immediate MDT.

[0066] Continuous MDT can facilitate the data preparation process if for example a measurement is taken from the “same” UE in different RRC states. This is because measurements such as Reference Signal Received Power (RSRP) or Reference Signal Received Quality (RSRQ) measurements may have a large deviation, for example across chip vendors. To be able to compare the different values reported by different UEs, data preparation normalizing these values needs to be performed per UE implementation. If MDT can correlate measurements from the same UE across RRC states, then this normalization is not needed since the same UE will be giving the same error in the data measurements and data preparation becomes easier.

[0067] Another example where Continuous MDT could be useful is when data is collected to train an ML Model (e.g., a trajectory prediction ML model). In this case, it is easier to predict trajectories by collecting (time-series) of location data across RRC states from the same UE. This is because any two UEs cannot be assumed to be located at the same location, so it is hard to deduce if they are part of the same (identical) trajectory or they belong to two different trajectories. This determination could create errors by erroneously merging logs from different UEs. Those errors could be avoided if trajectory information is collected per UE. In addition, collecting data across RRC states is useful to build accurate data sets, not missing intermediate points or locations in the trajectory. Therefore continuous MDT tries to avoid missing data, or having long gaps in the data collection due to losing some measurements across RRC transitions of a UE.

[0068] Different algorithms for mobility are used in idle and connected mode. The UE will use an algorithm for cell reselection in idle mode (with some parameters provided via network configuration), while in connected mode mobility is under network control, but the network can also apply mobility policies differentiated per UE. Merging logs from different UEs can therefore lead to errors.

[0069] Signalling-based activation, which by definition targets a specific UE, provides access to such continuous measurement series because the OAM will have the knowledge of the trace sessions activated per UE, and the Core Network (e.g., AMF) may store the signallingbased MDT configuration and apply it each time the UE connects to the network. This ensures that there will be no interruption of measurement series because the CN activates immediate MDT each time the UE connects to the network, and the UE autonomously activates logged MDT measurements each time it transits to RRCJDLE. Also, transitions between RRC_INACTIVE and RRC_CONNECTED are handled in a similar way by the UE and the NG-RAN.

[0070] UE location, e.g., at cell level, is typically not known by the OAM system, which means that signalling-based activation is not suitable for certain scenarios where the chosen UEs need to be located in a certain area, characterized by a cell or set of cells. Some of the examples described herein consider obtaining continuous series of MDT measurements for UEs located in a given area, e.g., under the coverage of a given gNB or cell, or, to give some further examples, within a tracking area or set of tracking areas, hence using managementbased MDT activation.

[0071] Some examples described herein consider how to store an MDT configuration for later re-activation when the UE changes between states.

[0072] A RAN node may receive MDT configurations (logged MDT, immediate MDT) directly from the OAM, in which case the RAN node itself selects the UEs to be configured. This is called management-based MDT. For management-based MDT, the OAM provides the TR (Trace Reference), while the RAN node (e.g., NG-RAN node) allocates a TRSR (Trace Recording Session Reference) per selected UE.

[0073] The RAN node may also receive MDT configurations (logged MDT, immediate MDT) from the CN via UE-associated signalling. This case is called signalling-based MDT, and targets a specific UE.

[0074] For management-based MDT data collection with no International Mobile Subscriber Identity (IMSI) / lnternational Mobile station Equipment Identity (Software Version) (IMEI(SV)) / Subscription Permanent Identifier (SUPI) criteria in the case of non-split architecture, UE selection for MDT can be done in a radio network at a base station (e.g., gNB) based on the input information received from a management system and the user consent information stored in the base station. This can be performed for OAM input parameters comprising Area information, for example.

[0075] Figure 2 describes an example of how management-based MDT configuration can be performed. An example of how combined management activation of immediate and logged MDT can be performed is then considered, with respect to the method of Figure 2.

[0076] Figure 2 summarizes how MDT configuration can be performed using a cell traffic trace functionality, as described in 3GPP TS 32.422. The cell traffic trace functionality may be used, for example, for management-based MDT activation NG-RAN non-split architecture.

[0077] At 201, management system 220 sends a Trace Session activation request to a base station 214 (in this example, a gNB) including parameters for configuring MDT measurements. The parameters may include an indication of area of a network for management-based MDT. The gNB stores the parameters in a non-UE associated context. Management system 220 can validate that the Mobile Country Code (MCC) and Mobile Network Code (MNC) specified in the TR is the same as the PLMN supported by all the cells specified in an area scope in which MDT is being activated. If gNB 214 receives a request with a PLMN in the TR that does not match any PLMN in its list, it will ignore the request.

[0078] At 203, gNB 214 stores the MDT parameters sent at 201. At 205 and 207, at least one UE including UE 212 connects to gNB 214. At 205, Access and Mobility Management Function (AMF) 218 sends an initial context setup request or a handover request for the at least one UE. A list of management-based MDT PLMNs is also provided in a list. At 207, based on the list of management-based MDT PLMNs, gNB 214 stores within a UE context of UE 212 that management-based MDT is allowed for UE 212.

[0079] At 209, gNB 214 selects one or more UEs for management-based MDT. gNB 214 shall select the suitable UEs for MDT data collection. In some examples, the selection is based on the area received from the management system and the area where UE is located. In some examples, user consent information received from the CN as part of the managementbased MDT PLMN List Information Element (IE) may also be used to select suitable UEs. If the user is not in the specified area or if the Management based MDT PLMN List IE is not present in the UE context the UE is not selected by gNB 214 for MDT data collection. During UE selection, gNB 214 can take into account also the UE capability (MDT capability) when it selects UE 212 for logged MDT configuration. If a UE does not support logged MDT, the UE is not selected. For management-based immediate MDT, some measurements (e.g. M4, M5), applicable in RRC_CONNECTED only, are performed directly by the gNB 214, and if such measurements are requested in the MDT configuration, gNB 214 should start the measurement according to the received configuration. Details of the measurements are defined in 3GPP TS 37.320 and 3GPP TS 38.314.

[0080] At 211, if MDT activation in 201 is for logged MDT, a logged MDT configuration is sent to selected UE 212. In some examples, a logged MDT trace session is preserved in UE 212 until a duration time of the trace session expires, including also multiple idle or inactive periods interrupted by various RRC state transitions such as idle-connected-idle state transitions. UE 212 collects MDT measurements and logs according to its configuration until its memory reserved for MDT is full. If this happens, UE stops logging, stops the log duration timer and starts a further timer. In some examples, the further timer may be a 48-hour timer.

[0081] At 211, if MDT activation in 201 is for immediate MDT and includes measurements performed by UE 212, the corresponding measurements are configured towards UE 212 via RRC signalling defined in TS 38.331. These measurements may correspond to DL signal quantities like RSRP (Reference Signal Received Power), RSRQ (Reference Signal Received Quality), SINR (signal-to-noise and interference ratio) further described in 3GPP TS 38.215. In an example, the corresponding reporting may be configured to be event-triggered, defined by a threshold, or periodic. RRC configured measurements corresponding to Immediate MDT measurement configuration are deleted in the UE 212 together with the RRC context when entering RRC idle mode. If MDT activation in 201 is for immediate MDT and includes measurements performed by gNB 214, the gNB 214 autonomously activates these measurements without involvement of the UE 212. These measurements may be PDCP SDU Data Volume measurement, Average UE throughput measurement, Packet Delay measurement and Packet loss rate measurement, to give some examples. It can additionally be noticed that the gNB 214 may simply collect UE measurements already provided by the UE 212 without specific configuration towards UE 212, if these measurements correspond to to the immediate MDT configuration. The DL signal quantities listed above may be part of such measurements, and the same applies for the Power Headroom measurement defined in 3GPP TS 38.213 reported via the MAC layer. An overview of MDT measurements is provided in 3GPP TS 37.320, which is now summarised in the following paragraphs.

[0082] Immediate MDT configuration: For Immediate MDT, RAN measurements and UE measurements can be configured. The configuration for UE measurements is based on the existing RRC measurement procedures for configuration and reporting with some extensions for location information. If area scope is included in the MDT configuration provided to the RAN, the UE may be configured with respective measurement when the UE is connected to a cell that is part of the configured area scope.

[0083] Immediate MDT measurements may comprise at least one of the following: M1: DL signal quantities measurement results for the serving cell and for intra-frequency / lnter-frequency / inter-RAT neighbour cells, including cell / beam level measurement for NR cells only, TS 38.215. M2: Power Headroom measurement by UE, TS 38.213. M4: PDCP SDU Data Volume measurement separately for DL and UL, per DRB per UE, see TS 28.552. M5: Average UE throughput measurement separately for DL and UL, per DRB per UE and per UE for the DL, per DRB per UE and per UE for the UL, by gNB, see TS 28.552 . M6: Packet Delay measurement separately for DL and UL, per DRB per UE, TS 28.552 and TS 38.314. M7: Packet loss rate measurement separately for DL and UL, per DRB per UE, TS 28.552 and TS 38.314. M8: RSSI measurement by UE (for WLAN / Bluetooth measurement) see TS 38.331 . M9: RTT Measurement by UE (for WLAN measurement) see TS 38.331.

[0084] A logged measurement MDT configuration comprises at least one of: configuration of downlink pilot strength measurements logging for (E-)UTRA and NR. configuration of MBSFN measurement logging for E-UTRA. configuration of the triggering of logging events: for (E-)UTRAN: periodic measurement trigger is supported, for which the logging interval is configurable. The parameter specifies the periodicity for storing MDT measurement results. It should be configured in seconds in multiples of the applied IDLE mode DRX, i.e. multiples of 1.28s which is either a factor or multiple of the IDLE mode DRX. The UE behaviour is unspecified when the UE is configured with a DRX cycle larger than the logging interval. for NR: periodic measurement trigger is supported, for which the logging interval is configurable. The parameter specifies the periodicity for storing MDT measurement results. for E-UTRAN and NR: event-based trigger is supported, for which the logging interval is configurable, which determines periodical logging of available data (e.g. time stamp, location information), and the following two types of events are supported: measurement quantity-based event L1, for which the event threshold, hysteresis, and time to trigger are configurable. If the configured time to trigger is not a multiple of the DRX cycle, then the UE uses the next multiple of DRX cycle duration that is larger than the time to trigger for evaluating the event L1; out-of-coverage detection trigger. It should be noted that The logging configuration for event-based and periodical DL pilot strength logged measurements can be configured independently. One type of event can be configured to the UE. configuration of the logging duration. This configuration parameter defines a timer activated at the moment of configuration, that continues independent of state changes, RAT or RPLMN change. When the timer expires the logging is stopped and the configuration is cleared (except for the parameters that are required for further reporting e.g. network absolute time stamp, trace reference, trace recording session reference and TCE Id). network absolute time stamp to be used as a time reference to UE. TR parameter as indicated by the 0AM configuration as specified in TS 32.422. TRSR as indicated by the 0AM configuration as specified in TS 32.422. TCE Id as indicated by the 0AM configuration as specified in TS 32.422. MDT PLMN List, indicating the PLMNs where measurement collection and log reporting is allowed. It is either the Management Based MDT PLMN List or the Signalling Based MDT PLMN List, depending on how the Logged MDT task was initiated. configuration of a logging area. A UE will log measurements as long as it is within the configured logging area. The scope of the logging area may consist of one of: a list of up to 32 global cell identities. If this list is configured, the UE will only log measurements when camping in any of these cells. a list of up to 8 TAs or 8 Location Areas (LAs) or 8 RAs. If this list is configured, the UE will only log measurements when camping in any cell belonging to the preconfigured TA / LA / RAs. for NR, a list of inter-frequency neighbouring cells per frequency. 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 PLMN list. for NR, configuration of a list of neighbouring frequencies and / or cells, indicating the UE to include neighbouring cell's measurements as indicated in the list in the logged MDT report. for E-UTRA, configuration of target MBSFN area(s) for MBSFN measurement logging. 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. The target MBSFN area(s) is defined by a list of up to 8 entries, where each entry indicates a carrier frequency and optionally indicates a specific MBSFN area on a carrier frequency. configuration of the WLAN access point names, indicating the UE to attempt to obtain WLAN measurements associated to these access points. configuration of the Bluetooth beacon names, indicating the UE to attempt to obtain Bluetooth measurements associated to these beacons. for NR, configuration of the sensor names, indicating the UE to attempt to obtain sensor measurements. for E-UTRA, configuration indicating the UE to attempt to obtain uncompensated barometric pressure measurements. for NR, the network can use a flag to indicate if an early measurement / idle mode configuration has relevance for logged measurement purposes, indicating the UE is allowed to log the measurement results related to early measurement frequencies in the logged MDT report. for NR, logged MDT type flag, indicating the logged measurement configuration is the signalling based MDT.

[0085] At 213, depending on the configured anonymization level, gNB 214 may trigger Cell TrafficTrace procedure per selected UE towards AMF 218. IftheMDT anonymization requires the IMEI-TAC in the MDT record, gNB 214 sends the TRSR, TR, serving Cell Global Identity (CGI), and TCE IP Address in a CELL TRAFFIC TRACE message sent, at 215, by gNB 214 to AMF 218 via UE-associated signalling. When AMF 218 receives this signalling message containing the TRSR, TR, serving cell CGI, and the Privacy Indicator. At 217 AMF 218 looks up the subscriber identities (IMEI(SV)) of the given cell from its database, and may send the IMEI-Tracking Area Code (TAC) together with the TRSR, TR and serving cell CGI to the TCE 216.

[0086] At 219, UE 212 may send measurement results via RRC signalling to gNB 214. For immediate MDT, when gNB 214 receives the measurements from UE 212 in an RRC message, gNB 214 may store the measurements at 221 together with the UE 212’s serving cell CGI and the TR. For logged MDT, UE 212 is configured to perform logged MDT measurements in RRC_IDLE or RRCJNACTIVE. UE 212 may indicate the availability of MDT measurements, by means of a one-bit indicator, in e.g., the RRCSetupComplete message during connection establishment as specified in 3GPP TS 32.421. gNB 214 can decide to retrieve the logged measurements based on this indication by sending a RRC UElnformationRequest message to UE 212. UE 212 can answer with the collected MDT logs in UElnformationResponse message. gNB 214 may not retrieve MDT report from UE 212 if UE 212’s Registered PLMN (RPLMN) does not match the PLMN where TCE used to collect MDT data resides. When gNB 214 receives the MDT report from UE 212 at 219, gNB 214 may receive the TRSR, TR and TCE Id from the report, and compares the Trace PLMN (PLMN portion of Trace Reference) with the PLMN where TCE 216 used to collect MDT data resides. The MDT report maybe be discarded in the case of a mismatch in the comparison.

[0087] It should be noted that logged measurement configurations and logs may be maintained when UE 212 is in any state of a Radio Access Technology (RAT) even if there exist multiple periods of interruptions when UE 212 is in a different RAT. There exists a single logged measurement configuration for Logged MDT in UE 212 for a RAT. When network provides a configuration, previously configured logged measurement configurations will be replaced by the new one. Logged measurements corresponding to previous configuration will be cleared also. Network should be able to retrieve data before it is deleted (e.g., when a new configuration is given to the UE).

[0088] At 223, MDT records can be reported from gNB 214 to TCE 216. For logged MDT, the TCE Id is indicated in the MDT report is translated to the actual IP address of the TCE by the gNB before it forwards the measurement records. The address translation is based on mapping configured in the gNB. For immediate MDT, the IP address of the TCE is indicated for the gNB in the trace configuration.

[0089] At 225, correlation of MDT measurements obtained via MDT can be performed.

[0090] According to some examples, combined management-based activation of logged and immediate MDT may be performed to assist continuous MDT collection. A possible method for performing combined management-based activation of logged and immediate MDT is outlined below. The method is outlined with respect to the steps and entities of Figure 2 above, however it should be noted that the method is an example only, and that other alternative methods are envisaged.

[0091] Initially, the management system 220 sends a management-based logged MDT configuration to gNB 214. In this example, the management-based logged MDT configuration comprises a first TR, TR A. The management system 220 sends a management-based immediate MDT configuration to gNB 214. In this example, the management-based immediate MDT configuration comprises a second TR, TR B.

[0092] Base station node (gNB 214) then selects one or more of its served UEs (in this example, UE 212) for logged MDT and immediate MDT as per 209 in Figure 2. In this example, the logged MDT is given a first TRSR, TRSR a, and the immediate MDT is given a second TRSR, TRSR b, such that the logged MDT session for UE 212 has TR A, TRSR a and the immediate MDT for MDT session has TR B, TRSR b. The logged MDT configuration is sent to UE 212 as per 211 and the immediate MDT configuration is activated as per 211 by e.g., RRC measurements. IMEI TAG can be provided to TCE as per 213 to 217 of Figure 2.

[0093] Considering an example where UE 212 is initially in a connected state (e.g., RRC_CONNECTED), measurement results from immediate MDT (TR B) may be received by gNB 212 and stored in gNB 212, as per 219 and 221. If UE 212 were then to go to an idle mode (e.g., RRCJDLE), gNB 214 may send stored MDT measurements (TR B) to TCE 216 (as per 223). In the idle state, as per 211, UE 212 collects measurements according to the logged MDT configuration (TR A) and stores the measurements. When UE 212 connects again to the network (i.e., changes from the idle state to a connected state), UE 212 indicates availability of logged MDT measurements (TR A) and gNB 214 retrieves them as per 219, and forwards the log to the TCE 216 (as per 223). At this step the network may also reactivate the immediate MDT configuration for UE 212. In some examples, immediate MDT records and logged MDT records may be correlated to (as per 225).

[0094] According to examples described herein, when a base station selects a UE for management-based logged and immediate MDT (at 209 of Figure 2 or at 309 of Figure 3, discussed below), or at least before releasing the UE context, the UE sends the immediate MDT configuration to the CN to be stored by the CN, along with the full reference of the MDT session (e.g., identifiers TR X TRSR y). The CN sends back the information to the gNB when the UE changes back to the relevant state (e.g. when the UE reconnects from idle state), and the gNB uses this information to configure immediate MDT measurements (at 207 of Figure 2 or 307 of Figure 3).

[0095] Additionally, gNB may send the reference of the logged MDT session (TR A TRSR a) to be stored in the CN, receive (at 205 of Figure 2 or 305 of Figure 3) the information similarly as described above, and forward the reference of the logged MDT session (TR A TRSR a )to the TCE (at 223 of Figure 2 or 323 of Figure 3) for trace correlation purpose.

[0096] By storing an MDT configuration in the CN, the network ensures that exactly those UEs that were initially configured with the logged MDT configuration (TR A) are immediately configured with corresponding immediate MDT configuration (TR B) when they connect to the network.

[0097] An example for storing an MDT configuration before a UE switches states (e.g., from connected to idle, or from idle to connected) is now considered with respect to Figure 3. This allows the UE to re-activate the configuration when the UE later returns back to its original state, which helps to ensure that the correct MDT configuration is applied to an MDT session. For example, a gNB may store in a CN network node an immediate MDT configuration applicable to a UE while the UE is in a connected state. When the UE switches to an idle state, the UE may use a logged MDT configuration. When the UE switches back to the connected state, the immediate MDT configuration previously used for the UE can be retrieved from the CN and configured to the UE, and the UE can resume immediate MDT measurements. This provides an efficient method for continuous MDT.

[0098] At 301a, a network entity 320, which in this example comprises a management system 320, sends a logged MDT measurement configuration to gNB 314. In other examples, network entity may comprise a Network Data and Analytics Function (NWDAF), for example. In this example, the logged MDT measurement configuration comprises TR A. At 301b, management system 320 includes the TR of logged MDT (TR A) together with the immediate MDT configuration (TR B). In this example, it is assumed that a duration configured for the logged MDT session also applies to the corresponding immediate MDT session. In an example where the durations are different, one configuration will expire while the other is still active, enabling the operator to e.g. continue collecting immediate MDT measurements for a longer period of time. At 301 a / b, one or more MDT measurement configurations comprising at least one trace reference may be sent to gNB 314.

[0099] The one or more MDT measurement configurations sent at 301 a / b may comprise an area indication in which the MDT measurement configurations are to be used.

[0100] At 303, MDT parameters are stored at gNB 314. This may be performed as in 203 of Figure 2.

[0101] At 305, when a UE 312 switches from an idle state (e.g., RRC_IDLE) to a connected state (RRC_CONNECTED), AMF 318 determines whether a management-based MDT configuration (e.g., a management-based immediate MDT configuration) for the UE that was previously stored in the ON is still valid. This can be determined based on an MDT duration of the stored configuration and a time at which 305 is performed (for example, based on Absolute Start Time Info). If a stored configuration is valid, AMF 318 If so, the AMF includes the m-based immediate MDT configuration info in the Initial Context Setup Request message sent to the gNB. If the m-based immediate MDT configuration has expired, AMF 318 deletes the information.

[0102] By receiving the logging duration information, the gNB may stop the immediate MDT session if logging duration expires when UE 312 is in a connected state (e.g., RRC_CONNECTED).

[0103] In an alternative example, instead of the configuration validity being checked by AMF 318, as in 305 above, this can be performed by gNB 314 that can then indicate to AMF 318 to keep or delete the information.

[0104] The MDT measurement configuration may be sent via an initial context setup request message.

[0105] At 307, gNB 314 stores within UE context for UE 312 that management-based MDT is allowed. This could be performed similarly to 207, for example.

[0106] At 309, gNB 314 takes into account management-based immediate MDT info received in 301 as well as at 305 (if the MDT measurement configuration received at 305 is still valid) when selecting UEs for management-based MDT. The selected UEs may have an MDT measurement configuration received at either 301 or 305 to be applied to the selected UE in an MDT session identified by a TR and TRSR. In some examples, if the UE is selected for the configured management-based MDT session(s) for the first time, i.e. received at 301, gNB 314 stores at 309 current time as Absolute Start Time Info together with the immediate MDT configuration information. This information will serve as absolute time reference, together with configured session duration, for subsequent evaluations of MDT session expiry.

[0107] 311 to 321 may be performed similarly to 211 to 221 described above.

[0108] At 323, with the stored at least one MDT report (where an MDT report comprises MDT measurements), the logged MDT reference (TR A, TRSR a) is reported in order to allow correlation in the TCE 316 (together with immediate MDT reference (TR B, TRSR b)).

[0109] At 325, available, logged MDT and immediate MDT logs are correlated in TCE 316 based on logged MDT session reference (TR A, TRSR a).

[0110] At 327, base station 314 stores the immediate MDT configuration for UE 213 in CN node 318 (in this example, an AMF) by providing the MDT configuration to CN node 318. For example, the MDT configuration may be provided to CN node 318 in a NGAP UE Context Release Complete message. In some examples, the MDT configuration is stored when a UE is selected for the first time at 309 based on information received at 301 a / b, and / or 305, and is not needed to be stored in future selections of the same UE (as the MDT configuration is already stored in the CN). In some examples, the MDT configuration is stored based on a determination that the configuration is not expired, based on a comparison of MDT duration and Absolute Start Time Info.

[0111] The MDT configuration stored at 327 may comprise an immediate MDT configuration. The method of Figure 3 may repeat from the start after 327, and the stored MDT configuration may be provided at 305. In some examples, when the method of Figure 3 is repeated, 301 a / b and / or 303 may be skipped at the beginning of the repeat of the method.

[0112] In the event of a handover of UE 312 from base station node 314 to a target base station node, the MDT measurement configuration may be provided from the CN to the target base station node, which can then use the MDT measurement configuration for continuous MDT.

[0113] According to some examples, CN node 318 may provide, when UE 312 reconnects from an idle state, an immediate MDT configuration for UE 312 that has previously been stored in the CN.

[0114] According to some examples, an NGAP INITIAL CONTEXT SETUP REQUEST message (which may be sent at 305, for example) may include an additional information element “Management-based immediate MDT configuration”. In the NGAP protocol (described in 3GPP TS 38.413), this IE may have a Presence “O” (optionally present in the NGAP INITIAL CONTEXT SETUP REQUEST message), Criticality “YES” and Assigned Criticality “ignore” (these parameters are described in 3GPP TS 38.413).

[0115] According to some examples, an NGAP INITIAL CONTEXT RELEASE COMPLETE message (which may be sent at 327, for example) may include an additional information element “Management-based immediate MDT configuration”. This IE may have a Presence “O”, Criticality “YES” and Assigned Criticality “ignore”.

[0116] An example IE that indicates immediate configuration information received from CN (e.g., at 305) or provided from gNB to CN (e.g., at 327) is shown in Table 1. lE / Group Name Presence Range IE type and reference Semantics description Criticality Assigned Criticality Immediate MDT configuration M 9.3.1.167 Contains the immediate MDT configuration - - MDT duration M ENUMERA TED (10, 20, 40, 60, 90,120, ...) Indicates the duration of the combined logged and immediate MDT sessions. Unit: [minute]. Absolute Start Time Info M BIT STRING (SIZE (48)) Indicates an absolute time for start of the combined logged and immediate MDT session. Format is YY-MM-DD HH:MM:SS and using BCD encoding. The first / leftmost bit of the bit string contains the most significant bit of the most significant digit of the year and so on. Logged MDT NG-RAN Trace ID M OCTET STRING (SIZE(8)) Trace ID of the corresponding logged MDT session. This IE is composed of the following: Trace Reference defined in TS 32.422

[11] (leftmost 6 octets, with PLMN information encoded as in 9.3.3.5), and Trace Recording Session Reference defined in TS 32.422

[11] (last 2 octets). Table 1: An example management-based immediate MDT configuration IE.

[0117] Figure 4 shows an example method flow. The method may be performed, for example, 5 by a base station apparatus such as gNB 214 or gNB 314.

[0118] At 400, the method comprises receiving, from a network entity, one or more minimization of drive test, MDT, measurement configurations comprising at least one trace reference.

[0119] At 402, the method comprises selecting a user equipment based on the one or more 10 MDT measurement configurations, wherein an MDT measurement configuration of the one or more MDT measurement configurations is to be applied to the selected user equipment in an MDT session identified by a trace reference of the at least one trace reference and a trace recording session reference.

[0120] At 406, the method comprises: sending, to a core network node, the MDT measurement configuration for the MDT session of the one or more MDT measurement configurations, an identifier of the selected user equipment, the trace reference and the trace recording session reference.

[0121] According to some examples, the method comprises receiving the MDT measurement configuration from the core network node.

[0122] According to some examples, the MDT measurement configuration is received via an initial context setup request message.

[0123] According to some examples, the network entity comprises a management system or a Network Data Analytics Function.

[0124] According to some examples, the method comprises sending at least one MDT record from the MDT session of the user equipment to a Trace Collection Entity.

[0125] Figure 5 shows an example method flow. The method may be performed, for example, by a CN node, such as AMF 213, 318.

[0126] At 500, the method comprises receiving, from a first base station node, an MDT measurement configuration for a user equipment, an identifier of the user equipment, a trace reference and a trace recording session reference; wherein the MDT measurement configuration is applied to the user equipment in an MDT session identified by the trace reference and the trace recording session reference.

[0127] According to some examples, the method comprises sending the MDT measurement configuration to a second base station node.

[0128] According to some examples, the first base station node and the second base station node are different base station nodes.

[0129] According to some examples, the first base station node and the second base station node are the same base station node.

[0130] According to some examples, the MDT measurement configuration comprises duration information of the MDT session.

[0131] FIG. 6 illustrates an example of a control apparatus 660 for controlling a network. The control apparatus may comprise at least one random access memory (RAM) 611a, at least on read only memory (ROM) 611b, at least one processor 612, 613 and an input / output interface 614. The at least one processor 612, 613 may be coupled to the RAM 611a and the ROM 611b. The at least one processor 612, 613 may be configured to execute an appropriate software code 615. The software code 615 may, for example, allow the at least one processor 612, 613 to perform one or more steps of any method flow described herein. The software code 615 may be stored in the ROM 611b. The control apparatus 600 may be interconnected with another control apparatus 600 controlling another function of the RAN or the core network.

[0132] FIG. 7 illustrates an example of a terminal 700, such as a UE. The terminal 700 may be provided by any device capable of sending and receiving radio signals. In some examples, the terminal may comprise a user equipment, a mobile station (MS) or mobile device, such as a mobile phone or what is known as a ’smart phone’, a computer provided with a wireless interface card or other wireless interface facility (e.g., USB dongle), a personal data assistant (PDA) or a tablet provided with wireless communication capabilities, a machine-type communications (MTC) device, an Internet of things (loT) type communication device or any combinations of these or the like. The terminal 700 may provide, for example, communication of data for carrying communications. The communications may be one or more of voice, electronic mail (email), text message, multimedia, data, machine data and so on.

[0133] The terminal 700 may be configured to receive signals over an air or radio interface 707 via appropriate apparatus for receiving and may transmit signals via appropriate apparatus for transmitting radio signals. In FIG. 7, transceiver apparatus is designated schematically by block 706. The transceiver apparatus 706 may be provided, for example, by means of a radio part and associated antenna arrangement. The antenna arrangement may be arranged internally or externally to the mobile device.

[0134] The terminal 700 may be provided with at least one processor 701, at least one memory ROM 702a, at least one RAM 702b and other possible components 703 and 704 for use in software and hardware aided execution of tasks it is designed to perform, including control of access to and communications with access systems and other communication devices. The at least one processor 701 is coupled to the RAM 702b and the ROM 702a. The at least one processor 701 may be configured to execute an appropriate software code 708. The software code 708 may for example allow to perform one or more of steps of any method flow described herein. The software code 708 may be stored in the ROM 702a.

[0135] The processor, storage and other relevant control apparatus can be provided on an appropriate circuit board and / or in chipsets. This example is denoted by reference 702. The device may optionally have a user interface, such as key pad 705, touch sensitive screen or pad, combinations thereof or the like. Optionally, one or more of a display, a speaker and a microphone may be provided depending on the type of the device.

[0136] UEs, such as UE 312 in Figure 3 or UE 212 in Figure 2 may take the form of a terminal device 400 as schematically shown in Figure 7.

[0137] FIG. 8 shows a schematic representation of non-volatile memory media 800a (e.g. computer disc (CD) or digital versatile disc (DVD)) and 800b (e.g. universal serial bus (USB) memory stick) storing instructions and / or parameters 802 which when executed by a processor allow the processor to perform one or more of the steps of any method flow described herein.

[0138] It should be understood that the apparatuses may comprise or be coupled to other units or modules etc., such as radio parts or radio heads, used in or for transmission and / or reception. Although the apparatuses have been described, in some examples as one entity, different modules and memory may be implemented in one or more physical or logical entities.

[0139] It is noted that whilst some examples have been described in relation to 5G networks, similar techniques and / or mechanisms can be applied in relation to other networks and communication systems (e.g., 6G and beyond). Therefore, although certain examples were described above, by way of illustration with reference to certain example architectures for wireless networks, technologies and standards, other examples may be applied to any other suitable forms of communication systems than those illustrated and described herein.

[0140] It is also noted herein that while the above details various examples, there are several variations and modifications which may be made to any of the aforementioned example solutions without departing from the scope of the examples described herein.

[0141] s used herein, “at least one of the following: ” and “at least one of <a list of two or more elements*” and similar wording, where the list of two or more elements are joined by “and” or “or”, mean at least any one of the elements, or at least any two or more of the elements, or at least all the elements.

[0142] In general, the various examples may be implemented in hardware or special purpose circuitry, software, logic or any combination thereof. Some examples detailed in the subject disclosure may be implemented in hardware, while other aspects may be implemented in firmware or software which may be executed by a controller, microprocessor or other computing device, although the subject disclosure is not limited thereto. While various aspects of the subject disclosure may be illustrated and described as block diagrams, flow charts, or using some other pictorial representation, it is well understood that these blocks, apparatus, systems, techniques or methods described herein may be implemented in, as non-limiting examples, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof.

[0143] As used herein, the term “circuitry” may refer to one or more or all of the following examples:

[0144] (a) hardware-only circuit implementations (such as, implementations in only analog and / or digital circuitry) and

[0145] (b) combinations of hardware circuits and software, such as (as applicable):

[0146] (i) a combination of analog and / or digital hardware circuit(s) with software / firmware and

[0147] (ii) any portions of hardware processor(s) with software (including digital signal processor(s)), software, and memory(ies) that work together to cause an apparatus, such as a mobile phone or server, to perform various functions) and

[0148] (c) hardware circuit(s) and or processor(s), such as a microprocessor(s) or a portion of a microprocessor(s), that requires software (e.g., firmware) for operation, but the software may not be present when it is not needed for operation.

[0149] This definition of circuitry applies to all uses of this term herein, including in any claims. As a further example, as used herein, the term circuitry also covers an implementation of merely a hardware circuit or processor (or multiple processors) or portion of a hardware circuit or processor and its (or their) accompanying software and / or firmware. The term circuitry also covers, for example and if applicable to the particular claim element, a baseband integrated circuit or processor integrated circuit for a mobile device or a similar integrated circuit in server, a cellular network device, or other computing or network device.

[0150] The various examples detailed in the subject disclosure may be implemented by computer software executable by a data processor of the mobile device, such as in the processor entity, or by hardware, or by a combination of software and hardware. Computer software or program, also called program product, including software routines, applets and / or macros, may be stored in any apparatus-readable data storage medium and they comprise program instructions to perform particular tasks. A computer program product may comprise one or more computer-executable components which, when the program is run, are configured to carry out one or more steps of any method flow described herein. The one or more computer-executable components may be at least one software code or portions of it.

[0151] Further in this regard it should be noted that any blocks of the logic flow as in the Figures may represent program steps, or interconnected logic circuits, blocks and functions, or a combination of program steps and logic circuits, blocks and functions. The software may be stored on such physical media as memory chips, or memory blocks implemented within the processor, magnetic media such as hard disk or floppy disks, and optical media such as DVD and the data variants thereof, CD. The physical media may be implemented as a non-transitory media.

[0152] The term “non-transitory,” as used herein, is a limitation of the medium itself (e.g., tangible, not a signal) as opposed to a limitation on data storage persistency (e.g., RAM vs. ROM).

[0153] The memory may be of any type suitable to the local technical environment and may be implemented using any suitable data storage technology, such as semiconductor-based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory and removable memory. The data processors may be of any type suitable to the local technical environment, and may comprise one or more of general-purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs), application specific integrated circuits (ASIC), FPGA, gate level circuits and processors based on multi core processor architecture, as non-limiting examples.

[0154] Examples of the subject disclosure may be practiced in various components, such as integrated circuit modules. The design of integrated circuits is by and large a highly automated process. Complex and powerful software tools are available for converting a logic level design into a semiconductor circuit design ready to be etched and formed on a semiconductor substrate.

[0155] The scope of protection sought for the various examples described herein is set out by the independent claims. The examples, if any, described herein that do not fall under the scope of the independent claims are to be interpreted as examples useful for understanding various facets of the subject disclosure.

[0156] The foregoing description has provided by way of non-limiting examples to provide a full and informative description the subject disclosure. However, various modifications and adaptations may become apparent to those skilled in the relevant arts in view of the foregoing description, when read in conjunction with the accompanying drawings and the claims. However, all such and similar modifications of the teachings of this disclosure will still fall within the scope of the examples described herein. Indeed, there is a further example comprising a combination of one or more examples with any of the other examples previously described herein.

Claims

1. An apparatus comprising:means for receiving, from a network entity, one or more minimization of drive test, MDT, measurement configurations comprising at least one trace reference;means for selecting a user equipment based on the one or more MDT measurement configurations, wherein an MDT measurement configuration of the one or more MDT measurement configurations is to be applied to the selected user equipment in an MDT session identified by a trace reference of the at least one trace reference and a trace recording session reference; andmeans for sending, to a core network node, the MDT measurement configuration of the one or more MDT measurement configurations, an identifier of the selected user equipment, the trace reference and the trace recording session reference.

2. The apparatus according to claim 1, wherein apparatus comprises:means for receiving the MDT measurement configuration from the core network node.

3. The apparatus according to claim 2, wherein the MDT measurement configuration is received via an initial context setup request message.

4. The apparatus according to any preceding claim, wherein the network entity comprises a management system or a Network Data Analytics Function.

5. The apparatus according to claim 1 or claim 2, wherein the apparatus comprises:means for sending at least one MDT record from the MDT session of the user equipment to a Trace Collection Entity.

6. The apparatus according to any preceding claim, wherein the MDT measurement configuration comprises duration information for the MDT session.

7. The apparatus according to any preceding claim, the apparatus comprising:means for allocating the trace recording session reference to the MDT session.

8. The apparatus according to any preceding claim, wherein the one or more MDT measurement configurations further include at least one area indication, wherein the user equipment is selected based on the one or more MDT measurement configurations and the at least one area indication.

9. A method comprising:receiving, from a network entity, one or more minimization of drive test, MDT, measurement configurations comprising at least one trace reference;selecting a user equipment based on the one or more MDT measurement configurations, wherein an MDT measurement configuration of the one or more MDT measurement configurations is to be applied to the selected user equipment in an MDT session identified by a trace reference of the at least one trace reference and a trace recording session reference; andsending, to a core network node, the MDT measurement configuration for the MDT session of the one or more MDT measurement configurations, an identifier of the selected user equipment, the trace reference and the trace recording session reference.

10. The method according to claim 9, wherein the method comprises:receiving the MDT measurement configuration from the core network node.

11. The method according to claim 10, wherein the MDT measurement configuration is received via an initial context setup request message.

12. The method according to any of claims 9 to 11, wherein the network entity comprises a management system or a Network Data Analytics Function.

13. The method according to any of claims 8 to 11, wherein the method comprises:sending at least one MDT record from the MDT session of the user equipment to a Trace Collection Entity.

14. A computer program comprising instructions stored thereon for performing at least the following:receiving, from a network entity, one or more minimization of drive test, MDT, measurement configurations comprising at least one trace reference;selecting a user equipment based on the one or more MDT measurement configurations, wherein an MDT measurement configuration of the one or more MDT measurement configurations is to be applied to the selected user equipment in an MDT session identified by a trace reference of the at least one trace reference and a trace recording session reference; andsending, to a core network node, the MDT measurement configuration for the MDT session of the one or more MDT measurement configurations, an identifier of the selected user equipment, the trace reference and the trace recording session reference.

15. An apparatus comprising:means for receiving, from a first base station node, an MDT measurement configuration for a user equipment, an identifier of the user equipment, a trace reference and a trace recording session reference;wherein the MDT measurement configuration is applied to the user equipment in an MDT session identified by the trace reference and the trace recording session reference.

16. The apparatus according to claim 15, wherein the apparatus comprises:means for sending the MDT measurement configuration to a second base stationnode.

17. The apparatus according to claim 15 or claim 16, wherein the first base station node and the second base station node are different base station nodes.

18. The apparatus according to claim 15 or claim 16, wherein the first base station node and the second base station node are the same base station node.

19. The apparatus according to any of claims 15 to 18, wherein the MDT measurement configuration comprises duration information of the MDT session.

20. A method comprising:receiving, from a first base station node, an MDT measurement configuration for a user equipment, an identifier of the user equipment, a trace reference and a trace recording session reference; andwherein the MDT measurement configuration is applied to the user equipment in an MDT session identified by the trace reference and the trace recording session reference.

21. The method according to claim 20, wherein the method comprises:sending the MDT measurement configuration to a second base station node.

22. The method according to claim 20 or claim 21, wherein the first base station node and the second base station node are different base station nodes.

23. The method according to claim 20 or claim 21, wherein the first base station node and the second base station node are the same base station node.

24. The method according to any of claims 20 to 23, wherein the MDT measurement configuration comprises duration information for the MDT session.

25. A computer program comprising instructions stored thereon for performing at least the following:receiving, from a first base station node, an MDT measurement configuration for a user equipment, an identifier of the user equipment, a trace reference and a trace recording session reference;wherein the MDT measurement configuration is applied to the user equipment in an MDT session identified by the trace reference and the trace recording session reference.31

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