Steering of UE handover to target plmn

Abstract

A device may be provided which is configured as user equipment of a telecommunications network. The device may receive a measurement configuration which comprises cell information for neighboring cells and an event configuration from a base station. The device may obtain system information for at least a subset of the neighboring cells, which system information may be indicative of a characteristic of a telecommunications network to which a neighboring cell belongs. Based on the system information, the device may determine one or more preferred neighboring cells, perform signal measurements in respect of the preferred neighboring cell(s), determine an occurrence of an event, and when the event is determined to have occurred, send a measurement report indicative of the signal measurements to the base station. Furthermore, a base station may be configured to provide a measurement configuration to the device. In the measurement configuration, the base station may include an indicator indicating whether a neighboring cell belongs to the same telecommunications network as to which the UE is currently connected.

Description

[0001] STEERING OF UE HANDOVER TO TARGET PLMN

[0002] TECHNICAL FIELD

[0003] The invention relates to a device configured as user equipment of a telecommunications network, and to a method for being performed by a user equipment of a telecommunications network when the user equipment is connected to a cell of the telecommunications network. The invention further relates to a base station for operating a cell of a telecommunications network, and to a method for being performed by a base station which operates a cell of a telecommunications network. The invention further relates to a computer-readable medium comprising data representing instructions for causing a processor system to perform any one of the methods.

[0004] BACKGROUND

[0005] By supporting URLLC (Ultra Reliable Low Latency Communications) requirements with minimal interruption times, 5G and beyond-5G networks may enable automated and teleoperated transport use cases, which are expected to have a significant societal and industrial impact. For example, vehicular teleoperation, which may represent an initial step towards autonomous driving and other advanced Cooperative, Connected, and Automated Mobility (CCAM) use-cases, may represent a promising alternative for current road transport and logistics approaches.

[0006] Moreover, in the near future, vehicles are expected to increasingly use the network infrastructure to improve safety, enhance efficiency, reduce accidents, decrease traffic congestion, etc., for example by offloading computations to the edge.

[0007] However, to enable such mission-critical use cases, network connectivity may need to satisfy stringent latency requirements and remain uninterrupted. These requirements are challenging in a cross-border roaming scenario where a vehicle may switch from a serving Public Landline Mobile Network (also referred to as source PLMN or simply ‘source network’) to the PLMN of a different operator (target PLMN or simply ‘target network’). Traditional roaming solutions, such as local breakout (LBO) or home- routed (HR) roaming, may operate under the assumption that the existing PDU session is terminated at the source network and a new PDU session is established in the target network. However, the establishment of a new PDU session may result in prolonged interruption times that may be unacceptable in the context of vehicular services. To reduce such interruption times, the N14 interface may be used to transfer the UE context between the Access & Mobility Management Functions (AMFs) in the source and the target network, for example as described in the 3GPP technical specification TS 23.502, v18.5.0. This way, the UE may be handed over to a target PLMN and may resume its existing session at the target PLMN.

[0008] There is a need to be able to steer the handover of a UE to a target network, for example in order to ensure that a UE is handed over to a target network which supports stringent latency requirements. The need to steer the handover may not only apply to the handover between networks when switching country borders, but also more generally when switching between any two networks, e.g., due to lack of coverage, the inability of a source network to provide a sufficient QoS, etc. Similarly, while the previous examples relate to the automotive industry, there is a more general need to be able steer the handovers of any type of UE between any two networks.

[0009] US10880792B2 describes a method implemented in a radio access node.

[0010] The radio access node is said to receive a list of prioritized Public Land Mobile Network (PLMN) Identities (IDs). The list of prioritized PLMN IDs comprises a PLMN ID for a serving PLMN and one or more PLMN IDs for one or more PLMNs of one or more shared networks. The radio access node instructs the wireless device to search for suitable cells for handover on at least one PLMN identified in the list of prioritized PLMN IDs and receives a list of suitable cells for handover. The radio access node determines a target PLMN ID and a target cell ID based on the list of suitable cells and the list of prioritized PLMN IDs. The radio access node initiates handover of the wireless device to a target cell identified by the target cell ID in the target PLMN.

[0011] US10880792B2 may thus allow PLMNs to be prioritized in the handover of a UE. However, this prioritization is fully determined by the network.

[0012] It would be advantageous to enable local knowledge and / or local preferences of a UE to be taken into account when steering the handover of the UE.

[0013] SUMMARY

[0014] In accordance with a first aspect of the invention, a device is provided which may be configured as user equipment of a telecommunications network.

[0015] The device may comprise:

[0016] - a radio access network interface to connect to a cell of the telecommunications network;

[0017] - a processor subsystem which may be configured to, when connected via the radio access network to the cell of the telecommunications network: receive a measurement configuration from a base station which operates the cell, wherein the measurement configuration may comprise cell information for a plurality of neighboring cells within a neighborhood of the cell, wherein the cell information for a neighboring cell may include at least a radio frequency of the neighboring cell; receive an event configuration from the base station, wherein the event configuration may define an event by referring to a condition to be met by at least one signal measurement; obtain system information for at least a subset of the plurality of neighboring cells, wherein the system information for a neighboring cell may be indicative of a characteristic of a telecommunications network to which the neighboring cell belongs; based on the system information obtained for a respective neighboring cell, determine a preference for the neighboring cell, thereby determining one or more preferred neighboring cells; based on the cell information, perform signal measurements in respect of the one or more preferred neighboring cells; based on the signal measurements, determine an occurrence of the event, and when the event is determined to have occurred, send a measurement report indicative of the signal measurements to the base station.

[0018] In accordance with a further aspect of the invention, a method is provided of being performed by user equipment of a telecommunications network when the user equipment is connected to a cell of the telecommunications network.

[0019] The method may comprise:

[0020] - receiving a measurement configuration from a base station which operates the cell, wherein the measurement configuration may comprise cell information for a plurality of neighboring cells within a neighborhood of the cell, wherein the cell information for a neighboring cell may include at least a radio frequency of the neighboring cell;

[0021] - receiving an event configuration from the base station, wherein the event configuration may define an event by referring to a condition to be met by at least one signal measurement;

[0022] - obtaining system information for at least a subset of the plurality neighboring cells, wherein the system information for a neighboring cell may be indicative of a characteristic of a telecommunications network to which the neighboring cell belongs; - based on the system information obtained for a respective neighboring cell, determining a preference for the neighboring cell, thereby determining one or more preferred cells;

[0023] - based on the cell information, performing signal measurements in respect of the one or more preferred neighboring cells;

[0024] - based on the signal measurements, determining an occurrence of the event, and when the event is determined to have occurred, send a measurement report indicative of the signal measurements to the base station.

[0025] The above measures may involve a base station providing a measurement configuration and an event configuration to a device configured as User Equipment of a telecommunications network (henceforth also simply referred to as ‘UE’). Having received the measurement configuration and the event configuration, the UE may perform signal measurements, detect an occurrence of an event based on the signal measurements, and when the event is determined to have occurred, send a measurement report indicative of the signal measurements to the base station.

[0026] The measurement configuration may comprise cell information for a plurality of neighboring cells within a neighborhood of the cell. Such neighboring cells may also be referred to as ‘neighbor cells’. The cell information for a neighboring cell may include at least a radio frequency of the neighboring cell, such as a Synchronization Signal Block (SSB) frequency of the cell. Through the measurement configuration, the UE may be informed of radio frequencies at which neighboring cells operate. The event configuration, which may for example be a ‘reportConfig’, may comprise a description or definition of an event. The event may be described or defined by referring to a condition to be met by at least one signal measurement performed in respect of a neighboring cell or serving cell. For example, the event configuration may define an event which is met when the signal strength of the current cell, e.g., to which the UE is currently connected, is lower than a first threshold, while the signal strength of a neighboring cell is higher than a second threshold. Through the event configuration, the UE may be informed if and / or when to report signal measurements to the base station.

[0027] The above measures may together establish a mechanism by which the base station may instruct a UE to listen for and measure neighboring cells which may be suitable candidates for a handover, e.g., suitable target cells. Examples of the mechanism as described in this and the preceding two paragraphs may be known per se from 3GPP standards. For example, 3GPP technical specification TS 38.331 , v18.1.0, clause 5.5 describes a 5G base station in form of a gNodeB (gNB) which may include the measurement configuration and event configuration in a Radio Resource Control (RRC) Reconfiguration message which is sent to the UE.

[0028] To enable the UE to assert a degree of control over the handover process, and thereby to steer the handover process, the UE may be further configured to, after having received the measurement configuration, obtain system information for a number of the neighboring cells which are identified, at least by their radio frequency, in the measurement configuration. Such system information may be indicative of a characteristic of a telecommunications network to which a neighboring cell belongs. The UE may be enabled to obtain the system information on the basis of the measurement configuration, for example based on the aforementioned radio frequency. For example, the UE may listen to a respective cell to obtain the characteristic from a broadcast message of the cell, or may look-up the neighboring cell in an internal or external database, for example by looking up the radio frequency of the cell together with the UE’s geographical location in the database, to obtain the system information.

[0029] By way of the system information, the UE may obtain a characterization, at least in part, of the telecommunications network behind the cell. In some cases, this telecommunication network may be different from the currently serving network of the UEs, for example at a country border or at an edge of the coverage area of the home network. In such cases, the neighboring cell may be a potential target cell for a handover. The inventors have recognized that whether a neighboring cell is a desired target cell for handover may not only depend on the signal strength experienced at the UE, but also on the characteristics of the network to which the cell belongs. For example, it may be of relevance whether the network to which the cell belongs is capable of providing the required services, at a required quality level (e.g., in terms of latency, bandwidth), whether the network can provide a required network slice, etc. Based on the obtained characteristic of the network, the UE may determine whether the network to which the cell belongs is capable or has the potential of meeting its needs, which may be expressed by the UE as a preference for a respective neighboring cell. For example, the preference may be expressed by as a binary label, e.g., ‘preferred’ or ‘non-preferred’, or as a score expressing a degree of preference. As a result, a set of preferred cells may be identified, which may be a subset of the set of neighboring cells identified in the measurement configuration but which in some cases may also include all neighboring cells identified in the measurement configuration.

[0030] Having determined a set of preferred cells, the UE may perform one or more of the steps of i) performing signal measurements, ii) detecting events, and iii) measurement reporting, selectively or in an adapted manner for the set of preferred cells. It will be appreciated that by performing at least one of these steps selectively, e.g., not for non-preferred cells, or in an adapted manner, e.g., by prioritizing preferred cells, it may be avoided that a measurement report is sent to the base station for a nonpreferred cell which may cause the base station to initiate a handover to the nonpreferred cell. Namely, if signal measurement is omitted for a non-preferred cell, events may not be detected and events may not be reported to the base station in respect of the non-preferred cell. Likewise, if event detection is omitted for a non-preferred cell or if the reporting for a non-preferred cell is omitted, events may not be reported to the base station in respect of the non-preferred cell. The preference determined by the UE for respective neighboring cells may thus be used to selectively perform one or more, but not necessarily all, of steps i)-iii) performed by the UE. An example of carrying out a step in an adapted manner is that the UE may adjust a signal threshold defined in the event configuration for a non-preferred cell to avoid or reduce the chance of an event being detected in respect of the non-preferred cell. Another example of carrying out a step in an adapted manner is that the UE may report the measurements performed in respect of a non-preferred cell in a different manner which avoids or reduces the chance of the base station initiating a handover to the non-preferred cell as target cell.

[0031] By way of the above measures, the UE may steer or control the handover process. Namely, by designating a cell as non-preferred, the non-preferred cell may not, or may be less likely to, be reported to the base station. Effectively, by assigning and subsequently making use of a preference for individual cells, the UE may narrowdown the list of potential target cells provided by the base station and thereby influence the cell selection for a potential handover. Namely, the base station may typically only initiate a handover in respect of a target cell for which a measurement report is received. In the absence of such a measurement report, the base station may refrain from initiating a handover to this target cell. The UE may thereby avert a potential decision of a base station to initiate a handover to a non-preferred cell by not providing a measurement report for this cell, or reduce the likelihood of such a handover by providing a modified measurement report. The above measures may be based on the insight that a UE may be well-equipped to determine which target network is most suitable for its requirements. Namely, a UE may possess local knowledge and / or local preferences which may not be known to the home network or visited network. By enabling the UE to express its preference, better handover decisions may be taken, e.g., which better meets the needs of the UE. An example of such a need is a certain level of service, or a certain quality of service, for example as required by an application running on the UE or a service utilized or provided by the UE. A further advantage may be that the handover decision may be personalized to the unique needs of the UE or the type of UE or a group of UEs. Yet another advantage may be that the UE may make different decisions based on its current location, which may not be possible with a network-only approach. Yet a further advantage may be that the UE may be aware of its own internal state and / or the state of its surroundings, for example based on acquired sensor data, and may thereby adapt its preference to better match said state. Yet a further advantage may be that the handover may be steered without necessitating changes to the message protocol or format as utilized for the message exchange between the UE and the base station. Yet a further advantage may be that the above measures do not require changes at the base station or the network, e.g., the home network, visited network, serving network, and / or target network. A UE configured as set out above may thus act in a backward compatible manner with existing base stations and existing networks. Thereby, the above measures may also be combined with mechanisms which steer the handover at the network side.

[0032] In an embodiment, the processor subsystem may be configured to obtain at least part of the system information for a neighboring cell by listening for a broadcast message from the neighboring cell and decoding the broadcast message. In an embodiment, the broadcast message may be a System Information Block, SIB, message. In a more specific embodiment, the broadcast message may be a System Information Block Type 1, SIB1 , message. In an embodiment, the system information may comprise an identifier of the telecommunications network. In a more specific embodiment, the identifier may be a Public Land Mobile Network Identifier, PLMN-ID.

[0033] The inventors have recognized that cells may broadcast messages which may contain information which may be used by the UE to determine the characteristic(s) of a telecommunications network. For example, the inventors have recognized that System Information Block (SIB) messages, such as SIB1 messages, may comprise an identifier of the telecommunications network, such as a PLMN-ID. Such an identifier may be indicative of characteristics of the telecommunication network to which the neighboring cell belongs. For example, the identifier may indicate that the network to which the neighboring cell belongs is the same or a different network than that of the serving cell, which may indicate that the network has the same or different characteristics. An advantage of receiving the system information at least in part from a broadcast message of a respective cell is that a UE may at the request of the base station already listen to neighboring cells to perform measurements and may therefore not need to employ an additional mechanism to obtain system information such as the identifier of the neighboring cell. In addition, when receiving system information directly from a broadcast message, there is a near certainty that the neighboring cell as identified in the measurement configuration is indeed present in the vicinity of the UE.

[0034] In an embodiment, the processor subsystem may be configured to obtain at least part of the system information by searching an internal or external database. In addition to, or alternatively to obtaining at least part of the system information from broadcast messages, the UE may obtain at least part of the system information from an internal or external database. Such a database may be provided specifically for the purpose of allowing UEs to look-up system information, but may also be pre-existing.

[0035] In an embodiment, the processor subsystem may be configured to search the database using a query which includes at least one of:

[0036] - a geographical location of the device;

[0037] - system information from a broadcast message from the neighboring cell; and

[0038] - information which is comprised in the measurement configuration, such as the cell information of the neighboring cell.

[0039] The UE may use various types of information as part of a query to be able to identify system information for the telecommunication network(s) to which neighboring cells belong. An example is the geographical location of the UE, which may be used to determine which cells of which networks are operating in a vicinity of the UE. Another example is that information which is already received from a broadcast message from a neighboring cell may be used in a query to search for additional system information about the network to which the neighboring cell belongs. For example, an identifier, such as a PLMN-ID, may be used as part of a query to search for additional system information about the network identified by the identifier. This way, the system information may be obtained in a two-step process in which first the identifier of the network is obtained from a broadcast message and then additional system information, e.g., which is not available from broadcast messages, is obtained from the database. Yet another example is that information which is comprised in the measurement configuration may be used as part of the query. A specific example may be the cell information of the neighboring cell, e.g., its SSB frequency. It is noted that several of the above query terms may be combined in one or more queries.

[0040] In an embodiment, the processor subsystem may be configured to search the database for network slice information of the telecommunications network to which the neighboring cell belongs. An example of system information which may be of relevance to the UE to determine whether a neighboring cell is preferred or not may be network slice information. Namely, the UE may wish to make use of a network slice which has certain characteristics, for example to ensure that the network slice supports the requirements of an application running on the UE or a service utilized or provided by the UE. Such network slice information may typically not be available from broadcast messages but may be queried from a database. Such a database may be provided specifically for the purpose of allowing UEs to look-up network slice information, but may also be pre-existing. For example, a database may be provided which may list network slice types, capacities, and configurations, and their availability across different networks and which may allow the slice information for a particular network to be looked-up based on an identifier of the network, such as a PLMN ID.

[0041] In an embodiment, the processor subsystem may be configured to obtain the system information for at least one of:

[0042] - visited network cells amongst the plurality of neighboring cells, for example based on an indicator contained in the measurement configuration which indicates whether a neighboring cell is a visited network cell;

[0043] - select geographical locations of the device, for example at geographical borders or at coverage area boundaries of the telecommunications network; and

[0044] - select network conditions experienced by the telecommunications network.

[0045] It may not be needed for the UE to obtain the system information in all situations and / or for all neighboring cells. For example, if a neighboring cell belongs to the same network as the current serving cell, and in particular, if both cells belong to the home network, the UE may not need to obtain system information for the neighboring cell since such information may already be available or may not be relevant to the UE. However, if a neighboring cell does not belong to the same network, or in situations where there is a likelihood of a neighboring cell not belonging to the same network, the UE may wish to obtain system information for the other cell in order to be able to determine whether the other network to which the other cell belongs may be suitable to meet the UE’s needs. The UE may thus selectively obtain system information, for example only for network cells of other networks, e.g., for visited networks, or in situations in which there is a high likelihood that a neighboring cell is a visited cell. Such situations may for example be characterized by their geographical location or may be identified to the UE by the home network or currently serving network. An advantage of obtaining the system information selectively is that it can lessen the burden on the UE to acquire the system information. For example, obtaining the system information from a broadcast message may require a certain amount of listening time, which may increase power consumption, reduce bandwidth, etc. By only doing this selectively, the aforementioned detrimental effects may be mitigated.

[0046] In an embodiment, the processor subsystem may be configured to determine the one or more preferred neighboring cells:

[0047] - by assigning a preference score to a respective neighboring cell; and / or

[0048] - as a subset of the plurality of neighboring cells, for example by determining if a preference score of a respective neighboring cell exceeds a preference threshold.

[0049] The UE may assign a preference to a neighboring cell in various ways, for example by using a binary preference label or by assigning a preference score. In some examples, all neighboring cells identified in the measurement report may be assigned a preference score and the set of preferred cells may be formed by those cells of which their preference score exceeds a threshold. In other examples, the set of preferred cells may be formed by those cells which are assigned a ‘preferred’ label.

[0050] In an embodiment, the processor subsystem may be configured to adjust a selection and / or a preference scoring of the one or more preferred neighboring cells during or after the signal measurements, for example based on a signal strength of a neighboring cell being below or above a signal strength threshold. The preference of the UE for a neighboring cell may not only depend on the characteristic of the network to which the neighboring cell belongs, but also on other factors such as the signal strength. As such, the UE may take results from signal measurements into account and adjust the selection and / or the preference score of individual neighboring cells accordingly, for example by decreasing the preference score of neighboring cells with poor signal strength or by changing the label of such cells to ‘non-preferred’.

[0051] In an embodiment, the processor subsystem may be configured to determine the preference for a neighboring cell based on at least one of:

[0052] - an application requirement of an application running on the device;

[0053] - a service requirement of a service utilized or provided by the device;

[0054] - a geographical location of the device;

[0055] - a state of the device;

[0056] - a state of an environment of the device;

[0057] - a user preference; and

[0058] - a preference indicated by a home Public Land Mobile Network, HPLMN. The UE may use the characteristic(s) of the telecommunication network, to which a neighboring cell belongs, to determine whether the neighboring cell meets its requirements. Such requirements may arise from a variety of sources, such as an application running on the device or a service utilized or provided by the device. Another example is that the current geographical location of the device may affect the requirements of the UE in respect of the network of a neighboring cell. A specific example may be that UE may lower its requirements, for example in terms of network slice capabilities of a visited network, in a remote area in which signal strength is the most important factor. Another example is that the state of the device and / or the state of an environment of the device may affect the requirements of the UE in respect of the network of a neighboring cell. For example, a connected vehicle travelling on a major highway at rush hour may increase its requirements in terms of bandwidth and latency to ensure reliable edge processing of its sensor data for (semi-)autonomous driving. Yet another example is that a UE may adjust its requirements in respect of a visited network based on a user preference or a preference expressed by the home network.

[0059] In an embodiment, the processor subsystem may be configured to obtain the system information for the at least subset of the plurality of neighboring cells in a sequential process, and if during the sequential process a sufficient number of preferred neighboring cells is identified, for example by a preference score of a number of neighboring cells exceeding a preference threshold, terminate the sequential process. Obtaining the system information may incur costs, for example in terms of time or power consumption to listen for broadcast messages, query databases, etc. The UE may therefore stop obtaining system information once the UE has identified a sufficient number of preferred neighboring cells. This may be particularly relevant if (part of) the system information can only be obtained in a sequential manner. For example, a UE may only be capable of listening to one, or a limited number, of neighboring cells at a time in order to receive a broadcast message of the cell (s) . By terminating the sequential process before the system information for all neighboring cells is obtained, time savings and / or reduced power consumption may be achieved.

[0060] In an embodiment, the processor subsystem may be configured to modify the event configuration received from the base station by modifying the at least one signal measurement to be met, thereby obtaining a modified event configuration, and using the modified event configuration to determine the occurrence of the event in respect of the one or more preferred neighboring cells. By modifying the event configuration, the UE may influence a likelihood and / or frequency that an event is detected. By way of such modifications, the UE may prioritize a preferred cell, e.g., by lowering a signal threshold defined in the event configuration to increase the likelihood and / or frequency of the occurrence of the event, or de-prioritize a non-preferred cell, e.g., by raising the signal threshold to decrease said likelihood and / or frequency. In accordance with a further aspect of the invention, a base station is provided for operating a cell of a telecommunications network. It will be appreciated that the base station may also operate more than one cell of the telecommunications network. In other words, the base station may operate one or more cells.

[0061] The base station may comprise:

[0062] - a radio access network interface;

[0063] - a processor subsystem which may be configured to: generate a measurement configuration for a device which may be connected to the cell, wherein the measurement configuration may comprise cell information for a plurality of neighboring cells within a neighborhood of the cell, wherein the cell information for a neighboring cell may include at least a radio frequency of the neighboring cell, wherein the measurement configuration may further include an indicator whether or not a neighboring cell belongs to the telecommunications network; and via the radio access network interface, provide the device with the measurement configuration.

[0064] In accord with a further aspect of the invention, a method is provided of being performed by a base station which operates a cell of a telecommunications network. The method may comprise:

[0065] - generating a measurement configuration for a device which may be connected to the cell, wherein the measurement configuration may comprise cell information for a plurality of neighboring cells within a neighborhood of the cell, wherein the cell information for a neighboring cell may include at least a radio frequency of the neighboring cell, wherein the measurement configuration may further include an indicator whether or not a neighboring cell belongs to the telecommunications network; and

[0066] - providing the device with the measurement configuration.

[0067] The above measures may involve providing a measurement configuration from a base station to a UE which, unlike known measurement configurations, additionally includes an indicator whether a neighboring cell belongs to the same telecommunications network to which the UE is currently connected via the base station or to another telecommunications network. The indicator may for example be included in the cell information of a respective neighboring cell, for example in form of a data field that may contain a Boolean value. Such an indicator may be useful to a UE as it may enable the UE to selectively obtain system information for neighboring cells. Namely, it may not be needed for the UE to obtain the system information in all situations and / or for all neighboring cells. For example, if a neighboring cell belongs to the same network as the current cell, the UE may not need to obtain system information for the neighboring cell since such information may already be available or may not be relevant to the UE. However, if a neighboring cell does not belong to the same network, the UE may wish to obtain system information for the other network in order to be able to determine whether the other network may be suitable to meet the UE’s needs. The indicator in the measurement configuration may enable the UE to obtain the system information selectively for network cells of other networks. An advantage of obtaining the system information selectively is that it can lessen the burden on the UE to acquire the system information. For example, obtaining the system information from a broadcast message may require a certain amount of listening time, which may increase power consumption, reduce bandwidth, etc. By only doing this selectively, the aforementioned detrimental effects may be mitigated.

[0068] In accordance with a further aspect of the invention, a transitory or non- transitory computer-readable medium comprising data representing a computer program, the computer program comprising instructions for causing a processor system to perform any of the methods described in this specification.

[0069] It will be appreciated by those skilled in the art that two or more of the above-mentioned embodiments, implementations, and / or aspects of the invention may be combined in any way deemed useful.

[0070] Modifications and variations of any one of the above-mentioned entities (e.g., device, user equipment, base station, method, computer program), which correspond to the described modifications and variations of another one of these entities, may be carried out by a person skilled in the art on the basis of the present description.

[0071] BRIEF DESCRIPTION OF THE DRAWINGS

[0072] These and other aspects of the invention are apparent from and will be elucidated with reference to the embodiments described hereinafter. In the drawings, Fig. 1 shows a UE in form of a vehicle crossing multiple country borders, with the UE being initially connected to its home network (MNO1) and on its journey switching between multiple visited networks (MNO2, MNO3, MNO4, MNO5);

[0073] Fig. 2A-2C illustrate seamless roaming in which a UE is handed over to a target network and is able to resume its existing session at the target network;

[0074] Fig. 3 illustrates a base station sending an RRC (radio resource control) Reconfiguration message to a UE to instruct the UE to perform measurements; Figs. 4A-4B illustrate three UEs, which are initially connected to the network of MNO1 , crossing a border and having a preference for different target networks;

[0075] Fig. 5 shows a base station supplying UEs a list of all neighboring cells, and a respective UE deciding to measure only the cell which is preferred by the UE;

[0076] Fig. 6A shows a base station supplying UEs a list of neighboring cells which belong to the preferred PLMNs for the respective UE;

[0077] Fig. 6B shows a base station supplying UEs a list of all neighboring cells;

[0078] Fig. 7 shows a processor system which may be exemplary for a user equipment or a base station as described in this specification;

[0079] Fig. 8 shows a non-transitory computer-readable medium comprising data;

[0080] Fig. 9 shows an exemplary data processing system.

[0081] Reference signs list

[0082] The following list of references and abbreviations is provided for facilitating the interpretation of the drawings and shall not be construed as limiting the claims.

[0083] 5GC 5G core

[0084] APP application

[0085] CTRY country gNB gNodeB

[0086] HPLMN home public line mobile network

[0087] MNO mobile network operator

[0088] RRC radio resource control

[0089] UE user equipment

[0090] UPF user plane function

[0091] 1-63 messages / events

[0092] 100-106 user equipment

[0093] 110,112 border location

[0094] 120,122 base station (e.g., gNodeB)

[0095] 130, 132 user plane function

[0096] 140,142 mobile network operator edge node

[0097] 150 application

[0098] 160,162 5G core 200 system

[0099] 220 network interface

[0100] 222 received data

[0101] 224 sent data

[0102] 240 processor subsystem

[0103] 260 data storage

[0104] 300 non-transitory computer-readable medium

[0105] 310 stored data

[0106] 1000 exemplary data processing system

[0107] 1002 processor

[0108] 1004 memory element

[0109] 1006 system bus

[0110] 1008 local memory

[0111] 1010 bulk storage device

[0112] 1012 input device

[0113] 1014 output device

[0114] 1016 network adapter

[0115] 1018 application

[0116] DESCRIPTION OF EMBODIMENTS

[0117] The following embodiments are described in the context of a 5G telecommunications network adhering to one or more 3GPP, ETSI NFV and / or related standards. The following also specifically references a use case in which a UE in form of a vehicle crosses a country border. Nonetheless, the embodiments described in this specification are not confined solely to this context. Rather, they can be adapted and applied to any type of UEs, any type of use cases in which a UE switches networks, and other telecommunications networks, such as those adhering to different standards like earlier generation (e.g., 4G) or subsequent generation (e.g., 6G or 7G) standards.

[0118] It will be appreciated that in the following, references to the UE being connected to an ‘MNO’, being an abbreviation for mobile network operator, may be understood as the UE being connected to a mobile network which is operated by the respective mobile operator. Such a connection may technically involve the UE being connected to a cell of a base station which belongs to the respective network. References to ‘networks’ are to be understood as including references to mobile telecommunications networks such as public land mobile networks (PLMN).

[0119] Fig. 1 shows a UE 100 in form of a vehicle crossing multiple country borders, with the UE 100 being initially connected to a base station 120 of its home network in Germany (DE) which is operated by a first mobile network operator MNO1 and on its journey switching between multiple visited networks. Namely, the journey of the UE 100 is shown to involve the UE switching in the Netherlands (NL) to a visited network of a second mobile operator MNO2, in Belgium (BE) to a visited network of third mobile operator MNO3, in France (FR) to a visited network of a fourth mobile operator MNO4, and in Spain (ES) to a visited network of a fifth mobile operator MNO5. Fig. 1 may thereby show an example of a cross-border roaming scenario where a vehicle switches from their current serving network (source network) to the network of a different mobile network operator (target network) after crossing a country border.

[0120] Traditional roaming solutions, such as local breakout (LBO) or home-routed (HR) roaming, may operate under the assumption that an existing PDU session is terminated at the source network and a new PDU session is established in the target network. However, the establishment of a new PDU session may result in prolonged interruption times that may be unacceptable in the context of vehicular services.

[0121] To reduce such interruption times, 3GPP standards support the use of the N14 interface to transfer the UE context between the Access & Mobility Management Functions (AMFs) in the source and the target network. This way, the UE may be handed over to a target network and may resume its existing session at the target network. The above and similar mechanisms to reduce interruption times when switching networks may also be referred to as ‘seamless roaming’. It is noted that while the crossing of country borders is an exemplary use case for seamless roaming, the following measures are not limited to the crossing of country borders but rather apply to the switching between two networks for any other reason, e.g., due to lack of coverage, an inability of a current network to provide sufficient QoS, etc. Therefore, any embodiment described in this specification within the context of crossing of country borders is to be understood to generally apply to the switching between two networks.

[0122] Fig. 2A-2C show an example of seamless roaming in which a UE is handed over to a target network and is able to resume its existing PDU session at the target network. In the situation shown in Fig. 2A, a UE 100 is connected to a base station 120 which belongs to a network operated by MNO1. The base station 120 is located at a border location 110 between country A, in which MNO1 is operating, and country B. The border location 110 further includes a user plane function (UPF) 130 and an edge node 140 of MNO1. The edge node 140 is shown to comprise an instance of an application APP 150 which may serve the UE 100, for example to provide one or more vehicular services. Fig. 2A further shows a 5G core 160 of MNO1. In country B, another network may be operated by MNO2. At a border location 112, MNO2 may have a base station 122, a user plane function (UPF) 132 and an edge node 142. Fig. 2A further shows a 5G core 162 of MNO2. In the situation as shown in Fig. 2A, the UE 100 may have an active PDU session with the edge node 140 of MNO1 , for example with the application 150 running on the edge node 140. As the UE 100 approaches the country border between country A and country B, the UE 100 may be instructed by MNO1 in step 1 to measure one or more neighboring cells belonging to MNO2 and to report back to MNO1 if certain signal strength thresholds are met in respect of these one or more neighboring cells. If and when these conditions are met, the UE may inform MNO1 thereof, and MNO1 may in step 2 inform MNO2 via a message exchange between the respective 5G cores 160, 162 that a handover may be required for the UE. In response, MNO2 may in step 3 prepare the PDU session for the UE 100.

[0123] Fig. 2B shows MNO1 handing-over the UE 100 to MNO2 in step 4. After connecting to MNO2 in step 5, the UE’s 100 traffic may be routed back to MNO1 in step 5 using the PDU session prepared in step 3. The interruption time may be reduced or minimized by performing the handover between the two MNOs and by reusing the UE's 100 PDU session in MNO1. In such an example, the internet protocol (IP) address that is assigned to the UE 100 may not change or may not have to change.

[0124] Fig. 2C shows examples of interfaces which may be used internally within the respective networks of MNO1 and MNO2, such as the N2, N3, N4, and N6 interfaces, and interfaces between the networks of MNO1 and MNO2, such as the N14, N16, N9, and N27 interfaces. The latter type of interfaces may be used to establish seamless roaming from the network of MNO1 to the network of MNO2.

[0125] With continued reference to Fig. 2A, to be able to perform a handover process, the UE 100 may be instructed by MNO1 in step 1 to measure one or more neighboring cells belonging to MNO2 and to report back to MNO1 if certain signal strength thresholds are met in respect of these one or more neighboring cells and serving cell. For that purpose, the base station 120 which operates the cell to which the UE 100 is presently connected may provide a measurement configuration to the UE. The measurement configuration may be data which comprises cell information for a plurality of neighboring cells within a neighborhood of the cell. The cell information for a neighboring cell may include at least a radio frequency of the neighboring cell. The base station 120 may further provide an event configuration to the UE. The event configuration may define an event by referring to a condition to be met by at least one signal measurement. Step 1 as shown in Fig. 2A may thus comprise the base station 120 sending a measurement configuration and an event configuration to the UE.

[0126] Fig. 3 shows an example of a measurement configuration and event configuration which may be sent in step 10 by the base station 120, being in this example a gNodeB or in short a gNB, to the UE 100. The base station may for example send a RRC (radio resource control) Reconfiguration message which may contain:

[0127] • A configuration of measurement objects, which may be an example of a measurement configuration as described elsewhere in this specification. The configuration may comprise information about neighboring cells (‘measObjects’ in Fig. 3) which may be potential target cells for a handover.

[0128] • One or more event configurations, which may each contain a description of events that the UE 100 should inform the gNB 120 about (‘reportConfigs’ in Fig. 3). For example, an event may be defined by that the signal strength of the current serving cell is lower than a first threshold and, at the same time, the signal strength of a particular neighboring cell is higher than a second threshold.

[0129] After receiving this message, the UE 100 may start measuring the signal strength of the neighboring cells identified in the measurement configuration (e.g., identified in the received ‘measObjects’) and may check in step 11 if the signal strength measurements satisfy any of the events defined by the event configurations (e.g., defined by the received ‘reportConfigs’). If this is the case, the UE 100 may report the occurrence of the respective event to the gNB 120 by sending a Measurement Report in step 12. In response, the gNB may then in step 13 trigger a handover procedure.

[0130] Problems of the procedure described with reference to Fig. 3 may include:

[0131] • The UE may lack knowledge of which target cell is being measured and generally may not have control over the handover process. This may be disadvantageous in cases where a neighboring cell belongs to a different network, in which case the UE may not only be handed over to a different cell but may also be switched to a different network without having knowledge thereof or control thereover.

[0132] • The decision to switch to a particular neighboring cell may be based on measured signal strengths. This means that different UEs at similar locations may be directed to the same target network, which may not be optimal for each individual UE due to the UEs having different requirements and / or preferences, and / or due to the UEs running or using different services. For example, different UEs may have different home networks, e.g., HPLMNs, and there may be differences in the home networks’ roaming agreements or in whether the QoS that the visited network provides is sufficient for a UE. Moreover, the target network may become overloaded if many UEs are redirected to the same target network.

[0133] Fig. 4A illustrates the above problems. Here, UE2 102, UE3 104, and UE4 106 are shown to be travelling along a road in country A and being about to cross a country border into country B. UE2 102 may have MNO5 as the operator of its home network, while UE3 104 may have MNO6 and UE4 106 may have MNO7 as the operator of its home network. For country B, MNO5 may have a roaming agreement with the network of MNO2, while MNO6 may have a roaming agreement with the network of MNO3 and MNO7 may have a roaming agreement with the network of MNO4. However, the event configuration provided by the base station 120 to UE2 102, UE3 104, and UE4 106 may be defined solely based on signal strength and may therefore cause all three UEs to be handed over in step 21 to the base station and network of MNO2, for example as it may have a stronger signal at the border crossing.

[0134] Fig. 4B shows a desired scenario in which each UE is handed over to its preferred network, being in this example preferred due to the existence of a roaming agreement between the home network of a respective UE and a specific network in country B. Namely, UE2 102 is in step 31 handed over to the base station and network of MNO2, UE3 104 is in step 32 handed over to the base station and network of MNO3, and UE4 106 is in step 33 handed over to the base station and network of MNO4.

[0135] To enable the UE to steer the handover process and thereby to express its preference for a visited network, the processor subsystem of a respective UE may be configured to, after having received the measurement configuration and event configuration, for example as described with reference to Fig. 3, obtain system information for at least a subset of the plurality of neighboring cells, wherein the system information for a neighboring cell is indicative of a characteristic of a telecommunications network to which the neighboring cell belongs, based on the system information obtained for a respective neighboring cell, determine a preference for the neighboring cell, thereby determining one or more preferred neighboring cells, based on the cell information, perform signal measurements in respect of the one or more preferred neighboring cells, based on the signal measurements, determine an occurrence of the event, and when the event is determined to have occurred, send a measurement report indicative of the signal measurements to the base station.

[0136] The above-described steering of the handover process by the UE may also be referred to as a UE-based approach and may differ from a network-based approach in which for example the measurement configuration is generated by the base station to only list cells of networks which are generally preferred for a UE of this home network. The UE-based approach may have one or more of the following advantages:

[0137] • Granularity: compared to the aforementioned network-based approach, a UE-based approach may offer local control over preferences. This may enable the preferences to be determined at the individual UE level. For example, an application or service provider providing a service to an individual UE may also supply their preference to the UE to enable the UE to take their preference into account, thereby allowing preferences of other parties and entities besides the home network to be taken into account.

[0138] • Situational awareness: a UE-based approach may take situational factors into account, such as the UE's current location, the date at its location, the time of day at its location, the weather conditions at its location, or the number of UEs nearby. The home network may be unaware of such situational factors. For example, a UE may comprise one or more sensors which may allow the UE to at least in part determine its own state, e.g., the speed and direction in which the UE is travelling, and / or a state of its surroundings, e.g., the presence of a traffic jam. The state of the UE and / or of its surroundings may affect the UE’s preferences for visited networks.

[0139] • Adaptiveness: a UE-based approach may adapt to changing circumstances such as network congestion, road congestion, etc.

[0140] • Application or service awareness: A UE may have a plurality of simultaneous PDU sessions for different services at any time, and each of these services may prefer a specific target network. A UE-based approach may locally prioritize the preferences of certain services / applications at the expense of others.

[0141] • Slice awareness: a UE-based approach may take local network slice preferences or requirements into account. These preferences or requirements may for example originate from an application or services running on or utilized by the UE. The UE may take these local preferences and requirements into account.

[0142] • Per-UE optimization: a UE-based approach may be tailored to the specific needs of each UE, unlike network-based approaches that may be limited, e.g., for technical and / or practical reasons, to apply only to groups of UEs. The UE-based approach may enable UEs which use the same services but in different circumstances to be handed over to different target networks in view of the different circumstances.

[0143] • Resilience: a network-based approach may limit a UE to only switch to the preferred networks, e.g., as specified by the home network, while a UE-based approach may allow the UE to deviate from or adapt its own preferences in certain situations, e.g., based on the signal strengths the UE is currently measuring. Fig. 5 shows UE2 102, UE3 104, and UE4 106 each configured to steer the handover process. In this example, the base station 120 may supply a measurement configuration and one or more event configurations, for example in a form and manner as described with reference to Fig. 3. Fig. 5 further shows the following steps:

[0144] Step 41. Message exchange from base station to UE. In this step, the base station 120 may supply a measurement configuration to UE2 102, UE3 104, and UE4 106. The measurement configuration may comprise a configuration of neighboring cells. For example, each neighboring cell configuration may comprise cell information for the neighboring cell. In a specific example, the cell information may comprise a value of the SSB (Synchronization Signal Block) frequency of the neighboring cell. Step 41 may generally be performed in known manner, e.g., as specified by TS 38.331 , v18.1.0, clause 5.5. In some examples, the base station 120 may list all neighboring cells in the measurement configuration and not limit the measurement configuration to only those neighboring cells which belong to preferred networks. In other examples, the base station 120 may only list those neighboring cells which belong to visited networks which are preferred or not forbidden by the home network or service provider. In other examples, the base station 120 may identify in the measurement configuration which of the neighboring cells belong to visited networks, for example by including an indicator in the measurement configuration that indicates which neighboring cells are in the administrative domain of MNO1. Thereby, the UE may be indirectly informed of which of the neighboring cells do not belong to the administrative domain of MNO1 and thereby which of the neighboring cells belong to another network.

[0145] Steps 42 - 45 may be performed at and / or by each of the UE2 102, UE3 104, and UE4 106. The following refers to ‘UE’ to denote any of the UE 2 102, UE3 104, and UE4 106.

[0146] Step 42. The UE may store the list of neighboring cells as listed in the measurement configuration provided by the base station 120.

[0147] Step 43. This step may be performed for each neighboring cell listed in the measurement configuration. The UE may seek to obtain system information for the neighboring cell which is indicative of a characteristic of the network to which the neighboring cell belongs. In the example of Fig. 5, the UE may seek to obtain at least part of the system information by obtaining the PLMN ID of the respective neighboring cell by listening to a broadcast message of the neighboring cell. For example, the UE may listen for and decode MIB and SIB1 messages broadcast by the neighboring cell. The MIB and SIB1 messages may be briefly described as follows: • The MIB (Master Information Block) message may be transmitted periodically by a radio node (over the physical broadcast channel, PBCH) and may be a first message that may be decoded by the UE. The UE may obtain the MIB using the SSB frequency sent in step 41. The MIB message may provide information to the UE to acquire the SIB1 message.

[0148] • The SIB1 (System Information Block Type 1) message may be a second message the UE may decode. The SIB1 may carry cell access-related information, such as the PLMN ID and TAG.

[0149] Typically, in a non-roaming scenario, a UE may not have to acquire the MIB or SIB1 messages to measure the neighboring cells, as it may suffice to measure the primary and secondary sync signal (PSS and SSS) to calculate the physical cell ID and the signal strength. Acquiring the MIB and SIB1 messages may thereby introduce a time overhead at the UE, as the UE may spend more time measuring the neighboring cells, thereby decreasing the time the UE has to transmit or receive user data. The overhead needed for the UE to be able to identify the PLMN ID of a new neighboring cell from the MIB and SIB1 messages may be expressed as follows:

[0150] T = (TMIB + T;BI) [ms] where:

[0151] - TMIB may be the time needed to acquire the MIB message.

[0152] ■ TSIBI may be the time needed to acquire the SIB1 message, which may depend on the periodicity with which the SIB1 is transmitted by the neighboring cell.

[0153] If the PLMN ID of the neighboring cell is known by the UE, for example from a previously performed measurement, the UE may skip performing step 43 for the respective neighboring cell. This may reduce the aforementioned time overhead, and increase the time which may be available to the UE to transmit or receive user data.

[0154] Stepp 44. This step may be performed for each neighboring cell listed in the measurement configuration. The UE may compare each neighboring cell's PLMN ID to its internally stored list of preferred networks, e.g., PLMNs. This list of preferred PLMNs may for example be configured in the SIM card by the home network, e.g., HPLMN, or service provider. The list may be updated by the home network or the service provider when needed. In other examples, the list of preferred PLMNs may be locally updated by the UE and / or entirely locally generated by the UE. In this respect, it is noted that references to a 'list' of preferred PLMNs may indicate that the UE identifies a set of the PLMNs as preferred. The term 'list' may thus represent a labeling or other designation marking the PLMNs as preferred, without this being necessarily stored in a data structure explicitly representing a list. The term 'list' may thus also encompass embodiments where an explicit list data structure is absent.

[0155] Step 45. The UE may sort the neighboring cells in order of preference for the PLMN to which they belong. The UE may then select a subset of the neighboring cells, e.g., the top X most preferred neighboring cells, and may (continue to) perform signal strength measurements only for these cells. Here, the parameter X may be a configurable parameter. For example, if X = 1, the UE may only measure the most preferred neighboring cell, e.g., the neighboring cell which belongs to the PLMN that is most preferred among all neighboring cell’s PLMNs. Accordingly, in step 45, each UE may only perform measurements in respect of one or a select number of neighboring cells that belong to one or more preferred PLMNs. In the example of Fig. 5, UE2 102 may perform signal measurements in respect of a cell of MNO2, UE3 104 may perform signal measurements in respect of a cell of MNO3, and UE4 106 may perform signal measurements in respect of a cell of MNO4. It is noted that the parameter X may be selected to include all neighboring cells, for example in case all neighboring cell’s PLMNs are equally preferred or are equally non-preferred or if it is desired to have one or more backup cells for one or more initially preferred neighboring cell or if the preference for certain neighboring cells is effected in the following step 46, in which case the UE may perform signal measurements in respect of all neighboring cells.

[0156] Step 46. When the UE determines that an event as specified in the event configuration occurs and that a handover to a neighboring cell is desirable, for example due to the neighboring cell being a preferred neighboring cell, the UE may send a measurement report in respect of the occurred event to the base station 120. An example of the occurrence of an event may be that the neighboring cell has a signal strength above a threshold. Another example of the occurrence of an event is that a currently serving cell has a signal strength under a first threshold and the neighboring cell has a signal strength above a second threshold.

[0157] Steps 42-46 may be performed once a new measurement configuration is received by way of step 41 , e.g., if a RRC reconfiguration occurs. For example, a new measurement configuration may be received after the UE is handed over to a new serving cell since then the set of neighboring cells typically changes. It is noted that there may be an overlap between a first set of neighboring cells identified in the measurement configuration before the handover and a second set of neighboring cells identified in the measurement configuration after the handover. In some examples, the UE may determine which of the neighboring cells in the second set were already included in the first set, or more specifically, for which of the neighboring cells in the second set step 43 has previously been performed, and then skip the execution of step 43 in respect of these neighboring cells. In other examples, the UE may perform step 43 irrespective of whether step 43 was previously performed in respect of a cell.

[0158] While Fig. 5 shows a specific example of the UE-based approach, various variations and alternatives are possible, as described in subsequent sections.

[0159] Obtaining system information

[0160] The system information may be obtained by the UE in various ways, for example as described with reference to Fig. 5 from broadcast message(s) of a neighboring cell. Another example is that the UE may obtain at least part of the system information from an internal or external database. The UE may search such a database to determine characteristics of the network to which a cell belongs. As query term, the UE may for example use a current geographical location as this may be indicative of which cells are neighboring cells at the current geographical location. An additional or alternative query term may be information which is comprised in the measurement configuration, such as the cell information of the neighboring cell. While the cell information may not uniquely identify the neighboring cell, the cell information may be combined with other information, e.g., the aforementioned current geographical location or the cell information of the currently serving cell, to identify the neighboring cell more uniquely and thereby to identify the network to which the neighboring cell belongs. An additional or alternative query term may be system information which is obtained from a broadcast message from a neighboring cell. For example, the UE may first obtain the PLMN ID of the network to which a neighboring cell belongs from a broadcast message of the neighboring cell, and then look-up the PLMN ID in a database to obtain other relevant characteristics of the network, for example its slicing capabilities.

[0161] The system information may be obtained for only a subset of the neighboring cells. For example, when performing steps 42-45 as described with reference to Fig. 5, the UE may stop performing signal measurements in respect of neighboring cells if the UE finds a neighboring cell that belongs to a preferred network through signal measurements. In another example, the UE may be configured to performing signal measurements until N preferred cells are identified and may then stop searching. The parameter / V may be selected based on the number M of preferred cells. For example, if M cells are considered to be preferred by the UE, for example by their preference scores exceeding a threshold, the UE may perform signal measurements until at least MIN M,N) preferred cells are found, and may thereby search for N preferred cells up to a maximum of M. This way, the time spent on performing signal measurements may be reduced or even minimized and the time that the UE has available to transmit or receive data may be increased or even maximized.

[0162] Type of system information

[0163] The UE may obtain various types of system information to determine its preference for individual neighboring cells. For example, the UE may obtain the PLMN ID for neighboring cells and may optionally use the PLMN ID to obtain further system information, for example by using the PLMN ID to look-up the further system information in a database. In some examples, the system information may be comprised of several information elements which may be evaluated together by the UE to determine its preference for a cell. For example, individual information elements may include bandwidth characteristics of a network, supported network slice configurations and capabilities of the network, etc. It is noted that the preference for a respective neighboring cell may be based on the system information but also on other information which may be indicative of how well the characteristic(s) of the network fits preferences and requirements of the UE. For example, signal strength, the UE’s geographical location, or a planned trajectory of the UE may be used to determine the preference for a cell. A data element used to determine the preference may be generally referred to as a parameter.

[0164] By using a preference which is derived from several parameters, e.g., in form of a preference score which is obtained by weighting or otherwise combining several parameters, a balanced selection of preferred neighboring cells may be made. This may avoid situations in which the UE only designates one neighboring cell as preferred but which neighboring cell may never reach the signal strength needed to be suitable handover candidate, thereby causing a loss of connectivity when crossing the border due to a non-occurrence of a handover. Another example is that the UE may, based on the signal strength measurements, determine that the signal strength of one of its most preferred neighboring cells is very low or decreasing (e.g., by not being in line with its trajectory) and may as a result remove the cell from its preferred list or may at least ensure that also other neighboring cells are designated as being preferred.

[0165] Selecting neighboring cells to measure

[0166] When a UE performs signal measurements in respect of preferred cells, e.g., as in step 45 described with reference to Fig. 5, the UE may assess whether the preference for individual neighboring cells may need to be modified, e.g., by adding or removing specific cells to a list of preferred cells or by modifying their preference scores. One reason for modifying its preference may be that the UE may detect a decrease in the signal strength of one of its preferred cells over time. This decrease may indicate that the cell's propagation pattern is not aligned with the UE's trajectory and may thereby result in the UE ceasing to prefer the cell as a candidate cell for a handover. The UE may dynamically adjust for how many of the preferred cells signal measurements are to be performed. For example, the UE may perform signal measurements for the top- most preferred cells. The value of X may be dynamically adjusted. For example, the UE may increase X if the UE detects a decrease in signal strength of a preferred cell, thereby effectively adding more potential handover targets cells to the measurement process, and may decrease X if an increase in signal strength of a preferred cell is detected and a handover is deemed likely to occur, effectively removing potential handover targets cells from the measurement process.

[0167] Adjusting a preference for neighboring cells

[0168] The preference for neighboring cells may be determined by the UE itself, but also by other entities. For example, the home network or service provider(s) may have the ability to modify the list of preferred networks per UE, for example via remote Subscriber Identity Module (SIM) provisioning techniques. Such modifications may be due to several reasons, such as changes in the business agreement between the home network and other operators, which may affect the list of preferred networks. The home network or service provider may also choose different preferred target networks based on different use cases, such as automotive, manufacturing, building control, etc. The home network or service provider may also have different preferences for networks based on the network’s supported or required slices, services, ability to use the edge to offload computing, and / or Quality of Service (QoS) supported by each network. Moreover, the home network or service provider may have different preferences for different target networks at different geographical locations. For example, the preferred target network may change when the UE moves to a specific geographical location, even when all other parameters affecting the preference remain the same. Another example is that the home network or service provider may adjust their preference for networks when the capabilities of a target network change, for example in terms of supported or required slices, services, ability to use the edge to offload computing, and / or supported QoS. The UE may also be configured to enable a user to indicate his / her preference, for example via a user interface provided by the UE, such as a graphical user interface.

[0169] When the list of preferred networks changes, the UE may reassess the list of preferred neighboring cells, e.g., in steps 44 and 45 as previously described with reference to Fig. 5, and update the list accordingly before conducting new signal measurements. In this respect, it is noted that in some examples, there may be a 1 :1 relation between preferred networks and preferred cells, in that a preference for a network may indicate the same preference for a neighboring cell which belongs to the network. In such cases, there may only be one data structure representing the preference which may signify both the preference for the network and the respective cell. In other examples, the UE may separately determine a preference for the network and a preference for the neighboring cell which belongs to the network. For example, the preference for a network may be based on network characteristics while the preference for a cell may be based on the network characteristics and additional parameters, such as signal strength, geographical location of the UE, trajectory of the UE etc. In such examples, the UE may use the preference for a network, e.g., in form of a label or preference score, to determine the preference for the neighboring cell which belongs to the network, which preference may again be in form of a label or a preference score. In such examples, the preference for a network may at least partly be determined by the home network or service provider, which may influence the UE’s preference for a cell.

[0170] Using other parameters broadcasted by the target cell(s)

[0171] The steps described with reference to Fig. 5 are described for the UE obtaining the PLMN ID from broadcast messages. However, the UE may also obtain other parameters from broadcast messages, such as the tracking area identity (TAI), the uplink / downlink bandwidth, etc. The UE may for example use these other parameters directly when determining a preference for a network and / or neighboring cell, or as query terms when searching a database for characteristics of the network.

[0172] Using other SIB messages

[0173] The steps described with reference to Fig. 5 are described for the UE obtaining the PLMN ID from a SIB1 message. However, the UE may use the same process to obtain other relevant information from other SIB messages. Typically, the UE may first decode the SIB1 message to obtain scheduling information for other SIB messages (e.g., SIB2-SIB21). Moreover, the SIB1 message may indicate if other SIB messages are only provided on-demand, in which case the SIB1 message may also provide a physical random access channel (PRACH) configuration which may be decoded and used by the UE to request the desired SIB messages.

[0174] Acquiring system information selectively for roaming cells

[0175] Typically, most handovers that are performed with respect to a UE may not be between different networks but rather within a same network. Therefore, most of the neighboring cells that any given UE may measure may belong to the same network and operator as the currently serving cell. In situations where it is not possible or unlikely that a neighboring cell belongs to another network, it may not be needed to perform step 43 of the procedure described with reference to Fig. 5, since obtaining the system information from broadcast messages may require time and thus may represent unnecessary overhead in such situations. In this context, ‘another network’ may be defined as the network of another mobile network operator, and may typically be a visited network, e.g., VPLMN, if the UE is currently connected to the home network, e.g., HPLMN. The neighboring cells which belong to another network may thus not belong to the administrative domain of the MNO operating the network currently serving the UE. It may be desirable to perform step 43 only for neighboring cells which belong to such another network, e.g., only for roaming cells, and / or in situations where it is likely that at least some of the neighboring cells belong to another network, and / or in situations where it is likely that the UE may be handed over to another network.

[0176] For that purpose, the base station may indicate, for example in the measurement configuration or elsewhere, which neighboring cells belong to the current network, and / or which neighboring cells belong to another network, e.g., of another mobile network operator. For example, the base station may make use of so-called autonomous gaps, which may traditionally be used for measuring and reporting processes, to instruct the UE in step 41 which neighboring cells are roaming cells. This way, the UE may perform step 42 selectively for roaming cells, thereby increasing the time the UE has to transmit or receive user data and decreasing the time needed to perform signal measurements. Additionally, or alternatively, any other existing field in the measurement configuration, or a new field or a new message, may be used to indicate to the UE that a neighboring cell belongs to another network.

[0177] Alternatively or additionally to the base station indicating which cells belong to the current network, and / or which neighboring cells belong to another network, the obtaining of system information, e.g., from broadcast messages as in step 43, may be performed only in situations where it is likely that at least some of the neighboring cells belong to another network. Such situations may include those where the UE is near a border of the coverage of the currently serving network, which may be at a country border but also within a country. To identify such situations, the UE may use its current geographical location and compare the current geographical location against a coverage map or a country map. Alternatively or additionally, the obtaining of system information, e.g., from broadcast messages as in step 43, may be performed only in situations where it is likely that the UE may be handed over to another network. These situations may include the aforementioned borders of the coverage of the currently serving network, but also situations where the currently serving network encounters network issues or constraints. These network issues or constraints may for example include an overload of users, network congestion, equipment failures, maintenance activities, or fluctuations in network availability. Such issues may necessitate a handover to an alternate network that can better meet service quality requirements. The UE may be informed of the existence of such network issues or constraints via the service provider or home network or visited network, either directly or indirectly, for example by being issued a(nother) measurement configuration, and may in response prepare for a possible handover by obtaining system information in respect of the networks of neighboring cells and based thereon determine its preference for neighboring cells.

[0178] Adjusting the event / report configuration.

[0179] In some examples, the UE may modify an event configuration received from the base station and use the modified event configuration to determine the occurrence of the event in respect of the one or more preferred neighboring cells. This may relate to the following. The base station may use thresholds and / or other parameters in the event configuration, for example standard thresholds, which may not or be less suitable in certain circumstances. For example, some services may require early handover to maintain service quality (e.g., automotive services), while others, for example with less strict requirements (e.g., internet access), may tolerate signal degradation. However, the base station may be unaware of which service(s) the UE is using, and may thus provide an event configuration which may be unsuitable for the service(s) used by the UE. While the above refers to services, there may be a general mismatch between the preferences and requirements of a UE and the supplied event configuration.

[0180] To address this problem, the UE may modify one or more parameters of the event configuration parameters supplied by the base station, for example by modifying parameters of a ‘reportConfig’ included in the measurement configuration. By modifying the parameter(s), the UE may adjust when, e.g., at which signal strength, one or more signal measurements defined by the event configuration are met. For example, the UE may modify the parameter(s), such as a threshold, on a per-neighboring cell basis, for example depending on the currently running service(s). Additionally, the UE may use the preference for a respective neighboring cell when modifying the parameters. For example, the UE may set a lower threshold for a neighboring cell which belongs to a preferred network, since this may increase the likelihood of the UE being handed over to the preferred network. On the other hand, the UE may set a higher threshold for a neighboring cell which belongs to a less or non-preferred network. As a result, the UE may be handed over to this neighboring cell if the signal strength is very high, thereby decreasing the likelihood of being handed over to the non-preferred network.

[0181] Combination with network-based approach

[0182] The UE-based approach of the present disclosure may be combined with a network-based approach in which for example the measurement configuration is generated by the base station to only list cells of networks which are generally preferred for a UE of this home network. For example, as also shown in Fig. 6A, the base station 120 may in step 51 include only the neighboring cells of those networks in the measurement configuration which may be preferred by the respective home network. For example, the measurement configuration for UE2 102 may only identify neighboring cells which belong to the network of MNO2, whereas the measurement configuration for UE3 104 may only identify neighboring cells which belong to the network of MNO3, and the measurement configuration for UE4 106 may only identify neighboring cells which belong to the network of MNO4. The measurement configuration may thus effectively provide a filtered list of neighboring cells, and the UE may subsequently assign its own preference to the neighboring cells to steer the handover procedure. A potential disadvantage of such a combination is that the UE may be provided with a limited list of neighboring cells, which may cause the UE to experience service degradation or (in a worst case) service interruption if none of the neighboring cells identified in the measurement configuration are deemed suitable target cells for a handover by the UE, e.g., due to insufficient signal strength, etc.

[0183] Fig. 6B shows an alternative to the approach of Fig. 6A, in which the UE may be provided with a list of neighboring cells which may not yet be limited to the preferred cells of the home network. Accordingly, in step 61, the UEs may perform signal measurements in a similar manner as in step 45 of Fig. 5, and in step 62 the UE may report the measurement reports in a similar manner as in step 46 of Fig. 5. In step 63, which may be performed at and / or by the base station 120, the handover may only be performed if a particular measurement report which is received from the UE pertains to a network cell which is preferred or at least non-forbidden by the home network. In other words, the filtering of suitable target cells for a handover may not yet be performed when informing the UE of neighboring cells but only when deciding whether to perform a handover in response to a measurement report received from the UE.

[0184] In the Fig. 6A and 6B examples, the base station may use a so-called Handover restriction list (HRL) as defined in 3GPP technical specification TS 36.413, V18.1.0 or Mobility Restriction List (MRL) as defined by TS 38.413, v18.1.0, which may define restrictions for the handover to visited networks. For example, in the example of Fig. 6A, the HRL or MRL may be defined to exclude non-preferred networks and the base station 120 may apply the restrictions defined in the HRL or MRL to omit neighboring cells of non-preferred networks in the measurement configuration. In the example of Fig. 6B, the base station may use the HRL or MRL to decide whether to perform a handover in response to a measurement report received from the UE. In both cases, the base station may check if the HRL or MRL specifies restrictions which may be intended to restrict the handover of the UE to a respective neighboring cell and act accordingly. If the MRL contains a prioritized list of networks, the prioritization may be taken into account by the base station, e.g., to only take into account only neighboring cells of those networks which are prioritized in the MRL.

[0185] Fig. 7 shows a system 200 which may represent a device configured as user equipment of a telecommunications network. The user equipment may a user equipment as described elsewhere in this specification. The device may for example be a mobile device. The system 200 may comprise a network interface 220 for network data communication, e.g., to receive data 222 and to send data 224. The network interface 220 may be a wireless communication interface, such as a 4G, 5G or later generation radio interface. The system 200 may further comprise a processor subsystem 240 which may be configured, e.g., by hardware design or software, to perform the operations described in this specification pertaining to the device / UE.

[0186] In general, the processor subsystem 240 may be embodied by a single Central Processing Unit (CPU), such as a x86 or ARM-based CPU, but also by a combination or system of such CPUs and / or other types of processing units. As also shown in Fig. 7, the system 200 may comprise a data storage 260, which may comprise non-volatile memory such as flash memory, a solid-state drive, etc., and which may be used for long-term storage of data. Although not shown in Fig. 7, the system 200 may further comprise volatile memory for temporary storage of data.

[0187] Examples of user equipment or devices represented by the system 200 include, but are not limited to, mobile phones, tablets, smartwatches, Internet of Things (loT) devices such as home sensors, industrial monitors, and healthcare devices, vehicles like connected cars, autonomous vehicles, and smart bicycles, laptops with cellular capabilities, e-readers, portable gaming consoles, smart clothing, virtual reality (VR), augmented reality (AR), and mixed reality (XR) devices and headsets, etc.

[0188] In an alternative embodiment of the system 200 of Fig. 7, the system 200 may represent a base station as described in this specification. In such an embodiment, the system 200 may comprise a first network interface for backhaul communication, e.g., with other base stations and the core network, and a second network interface for cellular communication, e.g., with UEs. The first network interface may for example be a wired communication interface, e.g., a fiberoptic interface, or a wireless communication interface, e.g., a microwave interface. The second network interface may for example be a wireless communication interface, such as a 4G, 5G or later generation radio interface. Fig. 7 shows a network interface 220 which may be exemplary for either network interface. The processor subsystem 240 may take a form as previously described with reference to the device / UE, e.g., a single CPU or a combination or system of CPUs and / or other types of processing units, and may be configured to perform the operations described in this specification pertaining to the base station. The data storage 260 may similarly take the form as described above.

[0189] In general, each entity described in this specification may be embodied as, or in, a device or apparatus. The device or apparatus may comprise one or more (micro) processors which execute appropriate software. The processor(s) of a respective entity may be embodied by one or more of these (micro)processors. Software implementing the functionality of a respective entity may have been downloaded and / or stored in a corresponding memory or memories, e.g., in volatile memory such as RAM or in non-volatile memory such as Flash. Alternatively, the processor(s) of a respective entity may be implemented in the device or apparatus in the form of programmable logic, e.g., as a Field-Programmable Gate Array (FPGA). Any input and / or output interfaces may be implemented by respective interfaces of the device or apparatus. In general, each functional unit of a respective entity may be implemented in the form of a circuit or circuitry. A respective entity may also be implemented in a distributed manner, e.g., involving different devices or apparatus.

[0190] It is noted that any of the methods described in this specification, for example in any of the claims, may be implemented on a computer as a computer implemented method, as dedicated hardware, or as a combination of both. Instructions for the computer, e.g., executable code, may be stored on a computer-readable medium 300 as for example shown in Fig. 8, e.g., in the form of a series 310 of machine-readable physical marks and / or as a series of elements having different electrical, e.g., magnetic, or optical properties or values. The executable code may be stored in a transitory or non-transitory manner. Examples of computer-readable mediums include memory devices, optical storage devices, integrated circuits, servers, online software, etc. Fig. 8 shows by way of example a memory card 300.

[0191] Fig. 9 is a block diagram illustrating an exemplary data processing system 1000 that may be used in the embodiments described in this specification. Such data processing systems include data processing entities described in this specification, including but not limited to a device configured as user equipment of a telecommunications network and a base station. The data processing system 1000 may include at least one processor 1002 coupled to memory elements 1004 through a system bus 1006. As such, the data processing system may store program code within memory elements 1004. Furthermore, processor 1002 may execute the program code accessed from memory elements 1004 via system bus 1006. In one aspect, data processing system may be implemented as a computer that is suitable for storing and / or executing program code. It should be appreciated, however, that data processing system 1000 may be implemented in the form of any system including a processor and memory that is capable of performing the functions described within this specification. The memory elements 1004 may include one or more physical memory devices such as, for example, local memory 1008 and one or more bulk storage devices 1010. Local memory may refer to random access memory or other non- persistent memory device(s) generally used during actual execution of the program code. A bulk storage device may be implemented as a hard drive, solid state disk or other persistent data storage device. The data processing system 1000 may also include one or more cache memories (not shown) that provide temporary storage of at least some program code in order to reduce the number of times program code is otherwise retrieved from bulk storage device 1010 during execution.

[0192] Input / output (I / O) devices depicted as input device 1012 and output device 1014 optionally can be coupled to the data processing system. Examples of input devices may include, but are not limited to, for example, a microphone, a keyboard, a pointing device such as a mouse, a game controller, a Bluetooth controller, a VR controller, and a gesture-based input device, or the like. Examples of output devices may include, but are not limited to, for example, a monitor or display, speakers, or the like. Input device and / or output device may be coupled to data processing system either directly or through intervening I / O controllers. A network adapter 1016 may also be coupled to data processing system to enable it to become coupled to other systems, computer systems, remote network devices, and / or remote storage devices through intervening non-public or public networks. The network adapter may comprise a data receiver for receiving data that is transmitted by said systems, devices and / or networks to said data and a data transmitter for transmitting data to said systems, devices and / or networks. Radios, modems, cable modems, and ethernet cards are examples of different types of network adapter that may be used with data processing system 1000. As shown in Fig. 9, memory elements 1004 may store an application 1018. It should be appreciated that data processing system 1000 may further execute an operating system (not shown) that can facilitate execution of the application. The application, being implemented in the form of executable program code, can be executed by data processing system 1000, e.g., by processor 1002. Responsive to executing the application, the data processing system may be configured to perform one or more operations to be described herein in further detail.

[0193] For example, data processing system 1000 may represent a device configured as user equipment of a telecommunications network. In that case, application 1018 may represent an application that, when executed, configures data processing system 1000 to perform the functions described with reference to the device configured as user equipment or with reference to the user equipment. In another example, data processing system 1000 may represent an embodiment of a base station as described in this specification. In that case, application 1018 may represent an application that, when executed, configures data processing system 1000 to perform the functions described with reference to the base station.

[0194] An abstract for the present specification may read as follows: a device may be provided which is configured as user equipment of a telecommunications network. The device may receive a measurement configuration which comprises cell information for neighboring cells and an event configuration from a base station. The device may obtain system information for at least a subset of the neighboring cells, which system information may be indicative of a characteristic of a telecommunications network to which a neighboring cell belongs. Based on the system information, the device may determine one or more preferred neighboring cells, perform signal measurements in respect of the preferred neighboring cell(s), determine an occurrence of an event, and when the event is determined to have occurred, send a measurement report indicative of the signal measurements to the base station. Furthermore, a base station may be provided which may be configured to provide a measurement configuration to the device. In the measurement configuration, the base station may include an indicator indicating whether a neighboring cell belongs to the same telecommunications network as to which the UE is currently connected.

[0195] It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims.

[0196] In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. Use of the verb "comprise" and its conjugations does not exclude the presence of elements or stages other than those stated in a claim. The article "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. Expressions such as “at least one of” when preceding a list or group of elements represent a selection of all or of any subset of elements from the list or group. For example, the expression, “at least one of A, B, and C” should be understood as including only A, only B, only C, both A and B, both A and C, both B and C, or all of A, B, and C. The invention may be implemented by means of hardware comprising several distinct elements, and by means of a suitably programmed computer. In the device claim enumerating several means, several of these means may be embodied by one and the same item of hardware. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

Claims

1. CLAIMS1. A device configured as user equipment of a telecommunications network, comprising: a radio access network interface to connect to a cell of the telecommunications network; a processor subsystem configured to, when connected via the radio access network to the cell of the telecommunications network: receive a measurement configuration from a base station which operates the cell, wherein the measurement configuration comprises cell information for a plurality of neighboring cells within a neighborhood of the cell, wherein the cell information for a neighboring cell includes at least a radio frequency of the neighboring cell; receive an event configuration from the base station, wherein the event configuration defines an event by referring to a condition to be met by at least one signal measurement; obtain system information for at least a subset of the plurality of neighboring cells, wherein the system information for a neighboring cell is indicative of a characteristic of a telecommunications network to which the neighboring cell belongs; based on the system information obtained for a respective neighboring cell, determine a preference for the neighboring cell, thereby determining one or more preferred neighboring cells; based on the cell information, perform signal measurements in respect of the one or more preferred neighboring cells; based on the signal measurements, determine an occurrence of the event, and when the event is determined to have occurred, send a measurement report indicative of the signal measurements to the base station.

2. The device according to claim 1 , wherein the processor subsystem is configured to obtain at least part of the system information for a neighboring cell by listening for a broadcast message from the neighboring cell and decoding the broadcast message.

3. The device according to claim 2, wherein the broadcast message is aSystem Information Block, SIB, message, such as a System Information Block Type 1 , SIB1 , message.

4. The device according to any one of claims 1 to 3, wherein the system information comprises an identifier of the telecommunications network, such as a Public Land Mobile Network Identifier, PLMN-ID.

5. The device according to any one of claims 1 to 4, wherein the processor subsystem is configured to obtain at least part of the system information by searching an internal or external database, for example by searching the database for network slice information of the telecommunications network to which the neighboring cell belongs.

6. The device according to claim 5, wherein the processor subsystem is configured to search the database using a query which includes at least one of: a geographical location of the device; system information from a broadcast message from the neighboring cell; and information which is comprised in the measurement configuration, such as the cell information of the neighboring cell.

7. The device according to any one of claims 1 to 6, wherein the processor subsystem is configured to obtain the system information for at least one of: visited network cells amongst the plurality of neighboring cells, for example based on an indicator contained in the measurement configuration which indicates whether a neighboring cell is a visited network cell; select geographical locations of the device, for example at geographical borders or at coverage area boundaries of the telecommunications network; and select network conditions experienced by the telecommunications network.

8. The device according to any one of claims 1 to 7, wherein the processor subsystem is configured to determine the one or more preferred neighboring cells: by assigning a preference score to a respective neighboring cell; and / oras a subset of the plurality of neighboring cells, for example by determining if a preference score of a respective neighboring cell exceeds a preference threshold.

9. The device according to any one of claims 1 to 8, wherein the processor subsystem is configured to adjust a selection and / or a preference scoring of the one or more preferred neighboring cells during or after the signal measurements, for example based on a signal strength of a neighboring cell being below or above a signal strength threshold.

10. The device according to any one of claims 1 to 9, wherein the processor subsystem is configured to determine the preference for a neighboring cell based on at least one of: an application requirement of an application running on the device; a service requirement of a service utilized or provided by the device; a geographical location of the device; a state of the device; a state of an environment of the device; a user preference; and a preference indicated by a home Public Land Mobile Network, HPLMN.

11. The device according to any one of claims 1 to 10, wherein the processor subsystem is configured to obtain the system information for the at least subset of the plurality of neighboring cells in a sequential process, and if during the sequential process a sufficient number of preferred neighboring cells is identified, for example by a preference score of a number of neighboring cells exceeding a preference threshold, terminate the sequential process.

12. The device according to any one of claims 1 to 11 , wherein the processor subsystem is configured to modify the event configuration received from the base station by modifying the at least one signal measurement to be met, thereby obtaining a modified event configuration, and using the modified event configuration to determine the occurrence of the event in respect of the one or more preferred neighboring cells.

13. A base station for operating a cell of a telecommunications network, comprising: a radio access network interface; a processor subsystem configured to: generate a measurement configuration for a device which is connected to the cell, wherein the measurement configuration comprises cell information for a plurality of neighboring cells within a neighborhood of the cell, wherein the cell information for a neighboring cell includes at least a radio frequency of the neighboring cell, wherein the measurement configuration further includes an indicator whether or not a neighboring cell belongs to the telecommunications network; and via the radio access network interface, provide the device with the measurement configuration.

14. A method for being performed by a user equipment of a telecommunications network when the user equipment is connected to a cell of the telecommunications network, comprising: receiving a measurement configuration from a base station which operates the cell, wherein the measurement configuration comprises cell information for a plurality of neighboring cells within a neighborhood of the cell, wherein the cell information for a neighboring cell includes at least a radio frequency of the neighboring cell; receiving an event configuration from the base station, wherein the event configuration defines an event by referring to a condition to be met by at least one signal measurement; obtaining system information for at least a subset of the plurality neighboring cells, wherein the system information for a neighboring cell is indicative of a characteristic of a telecommunications network to which the neighboring cell belongs; based on the system information obtained for a respective neighboring cell, determining a preference for the neighboring cell, thereby determining one or more preferred cells; based on the cell information, performing signal measurements in respect of the one or more preferred neighboring cells; based on the signal measurements, determining an occurrence of the event, and when the event is determined to have occurred, send a measurement report indicative of the signal measurements to the base station.

15. A method of being performed by a base station which operates a cell of a telecommunications network, comprising: generating a measurement configuration for a device which is connected to the cell, wherein the measurement configuration comprises cell information for a plurality of neighboring cells within a neighborhood of the cell, wherein the cell information for a neighboring cell includes at least a radio frequency of the neighboring cell, wherein the measurement configuration further includes an indicator whether or not a neighboring cell belongs to the telecommunications network; and providing the device with the measurement configuration.

16. A transitory or non-transitory computer-readable medium comprising data representing a computer program, the computer program comprising instructions for causing a processor system to perform the method according to claim 14 or 15.

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