Enhanced cell switch condition evaluation in lower layer triggered mobility, and related devices, methods and computer programs

Abstract

Devices, methods and computer programs for enhanced cell switch condition evaluation in lower layer triggered mobility are disclosed At least some example embodiments may allow At least some example embodiments may allow using radio resource measurements to rank frequency layers, carriers, cells and / or reference signals for which a lower layer triggered mobility condition evaluation is to be performed.

Description

[0001] ENHANCED CELL SWITCH CONDITION EVALUATION IN LOWER LAYER TRIGGERED MOBILITY, AND RELATED DEVICES, METHODS AND COMPUTER PROGRAMS

[0002] TECHNICAL FIELD

[0003] The disclosure relates generally to communications and, more particularly but not exclusively, to enhanced cell switch condition evaluation in lower layer triggered mobility, as well as related devices, methods and computer programs.

[0004] BACKGROUND

[0005] Lower layer (for example, layer 1 (L1) and / or layer 2 (L2)) triggered mobility (LTM) is a mobility procedure in which a network configures a user device with, for example, up to 8 candidate cells, and eventually sends a cell switch command to the user device to perform a cell switch to one of those cells.

[0006] An improvement to traditional LTM, known as conditional LTM (CLTM), is being developed. In CLTM, a user device may be configured with multiple conditions for a conditional cell switch to one of multiple candidate cells in an LTM candidate cell configuration.

[0007] However, at least in some situations, in CLTM the number of configured cells for mobility may be high resulting in that the user device may be required to track multiple conditions across multiple frequency layers, carriers and / or cells simultaneously.

[0008] Additionally, at least in some situations, the network may not know how the configurations impact the CLTM cell switches across different user devices.

[0009] Accordingly, at least in some situations, it may be beneficial to provide enhanced cell switch condition evaluation in lower layer triggered mobility.

[0010] BRIEF SUMMARY

[0011] The scope of protection sought for various example embodiments of the invention is set out by the independent claims. The example embodiments and features, if any, described in this specification that do not fall under the scope of the independent claims are to be interpreted as examples useful for understanding various example embodiments of the invention.

[0012] An example embodiment of a user device comprises at least one processor, and at least one memory storing instructions that, when executed by the at least one processor, cause the user device at least to transmit a candidate cell evaluation capability indication to a serving network node in a serving cell in preparation for a lower-layer triggered mobility, LTM, -based cell switch from the serving cell to a target cell. The target cell is to be selected from multiple candidate cells. The candidate cell evaluation capability indication indicates a candidate cell evaluation capability of the user device. The instructions, when executed by the at least one processor, further cause the user device at least to receive candidate cell configuration information from the serving network node. The instructions, when executed by the at least one processor, further cause the user device at least to select, based at least on the indicated candidate cell evaluation capability of the user device and the received candidate cell configuration information, a subset of the multiple candidate cells or associated beams for evaluating one or more LTM -based cell switch related evaluation conditions.

[0013] An example embodiment of a method comprises, in preparation for a lower- layer triggered mobility, LTM, -based cell switch from a serving cell to a target cell, the target cell to be selected from multiple candidate cells, transmitting, from a user device in the serving cell, a candidate cell evaluation capability indication to a serving network node in the serving cell, the candidate cell evaluation capability indication indicating a candidate cell evaluation capability of the user device. The method further comprises receiving, at the user device, candidate cell configuration information from the serving network node. The method further comprises, based at least on the indicated candidate cell evaluation capability of the user device and the received candidate cell configuration information, selecting, by the user device, a subset of the multiple candidate cells or associated beams for evaluating one or more LTM -based cell switch related evaluation conditions.

[0014] An example embodiment of a non-transitory computer readable medium comprises program instructions that, when executed by a user device, cause the user device to perform at least the following: in preparation for a lower-layer triggered mobility, LTM, -based cell switch from a serving cell to a target cell, the target cell to be selected from multiple candidate cells, transmitting a candidate cell evaluation capability indication to a serving network node in the serving cell, the candidate cell evaluation capability indication indicating a candidate cell evaluation capability of the user device; receiving candidate cell configuration information from the serving network node; and based at least on the indicated candidate cell evaluation capability of the user device and the received candidate cell configuration information, selecting a subset of the multiple candidate cells or associated beams for evaluating one or more LTM -based cell switch related evaluation conditions.

[0015] An example embodiment of a user device comprises at least one processor, and at least one memory storing instructions that, when executed by the at least one processor, cause the user device at least to transmit a candidate cell evaluation capability indication to a serving network node in a serving cell in preparation for a lower-layer triggered mobility, LTM, -based cell switch from the serving cell to a target cell. The candidate cell evaluation capability indication indicates a candidate cell evaluation capability of the user device. The target cell is to be selected from multiple candidate cells. The instructions, when executed by the at least one processor, further cause the user device at least to receive from the serving network node candidate cell configuration information and an indication of a subset of the multiple candidate cells to select. The instructions, when executed by the at least one processor, further cause the user device at least to select a subset of the multiple candidate cells or associated beams for evaluating one or more LTM -based cell switch related evaluation conditions based at least on the received indication of the subset of the multiple candidate cells to select.

[0016] An example embodiment of a method comprises, in preparation for a lower- layer triggered mobility, LTM, -based cell switch from a serving cell to a target cell, the target cell to be selected from multiple candidate cells, transmitting from a user device a candidate cell evaluation capability indication to a serving network node in the serving cell, the candidate cell evaluation capability indication indicating a candidate cell evaluation capability of the user device. The method further comprises receiving at the user device from the serving network node candidate cell configuration information and an indication of a subset of the multiple candidate cells to select. The method further comprises, based at least on the received indication of the subset of the multiple candidate cells to select, selecting, by the user device, a subset of the multiple candidate cells or associated beams for evaluating one or more LTM -based cell switch related evaluation conditions.

[0017] An example embodiment of a non-transitory computer readable medium comprises program instructions that, when executed by a user device, cause the user device to perform at least the following: in preparation for a lower-layer triggered mobility, LTM, -based cell switch from a serving cell to a target cell, the target cell to be selected from multiple candidate cells, transmitting a candidate cell evaluation capability indication to a serving network node in the serving cell, the candidate cell evaluation capability indication indicating a candidate cell evaluation capability of the user device; receiving from the serving network node candidate cell configuration information and an indication of a subset of the multiple candidate cells to select; and based at least on the received indication of the subset of the multiple candidate cells to select, selecting a subset of the multiple candidate cells or associated beams for evaluating one or more LTM -based cell switch related evaluation conditions.

[0018] An example embodiment of a serving network node in a serving cell comprises at least one processor, and at least one memory storing instructions that, when executed by the at least one processor, cause the serving network node at least to receive a candidate cell evaluation capability indication from a user device in a serving cell in preparation for a lower-layer triggered mobility, LTM, -based cell switch from the serving cell to a target cell. The target cell is to be selected from multiple candidate cells. The candidate cell evaluation capability indication indicates a candidate cell evaluation capability of the user device. The instructions, when executed by the at least one processor, further cause the serving network node at least to transmit to the user device candidate cell configuration information and an indication of a subset of the multiple candidate cells to select.

[0019] An example embodiment of a method comprises, in preparation for a lower- layer triggered mobility, LTM, -based cell switch from a serving cell to a target cell, the target cell to be selected from multiple candidate cells, receiving at a serving network node a candidate cell evaluation capability indication from a user device in the serving cell, the candidate cell evaluation capability indication indicating a candidate cell evaluation capability of the user device. The method further comprises transmitting from the serving network node to the user device candidate cell configuration information and an indication of a subset of the multiple candidate cells to select.

[0020] An example embodiment of a non-transitory computer readable medium comprises program instructions that, when executed by a user device, cause the a serving network node to perform at least the following: in preparation for a lower-layer triggered mobility, LTM, -based cell switch from a serving cell to a target cell, the target cell to be selected from multiple candidate cells, receiving a candidate cell evaluation capability indication from a user device in the serving cell, the candidate cell evaluation capability indication indicating a candidate cell evaluation capability of the user device; and transmitting to the user device candidate cell configuration information and an indication of a subset of the multiple candidate cells to select.

[0021] DESCRIPTION OF THE DRAWINGS

[0022] The accompanying drawings, which are included to provide a further understanding of the embodiments and constitute a part of this specification, illustrate embodiments and together with the description help to explain the principles of the embodiments. In the drawings:

[0023] FIG. 1 shows an example embodiment of the subject matter described herein illustrating an example system, where various embodiments of the present disclosure may be implemented;

[0024] FIG. 2A shows an example embodiment of the subject matter described herein illustrating a user device;

[0025] FIG. 2B shows an example embodiment of the subject matter described herein illustrating a network node device;

[0026] FIG. 3A shows an example embodiment of the subject matter described herein illustrating a method; FIG. 3B shows an example embodiment of the subject matter described herein illustrating another method; and

[0027] FIG. 3C shows an example embodiment of the subject matter described herein illustrating yet another method.

[0028] Like reference numerals are used to designate like parts in the accompanying drawings.

[0029] DETAILED DESCRIPTION

[0030] Reference will now be made in detail to embodiments, examples of which are illustrated in the accompanying drawings. The detailed description provided below in connection with the appended drawings is intended as a description of the present examples and is not intended to represent the only forms in which the present example may be constructed or utilized. The description sets forth the functions of the example and the sequence of steps for constructing and operating the example. However, the same or equivalent functions and sequences may be accomplished by different examples.

[0031] Fig. 1 illustrates example system 100, where various embodiments of the present disclosure may be implemented. System 100 may comprise radio access network cell 110 of, e.g., a fifth generation (5G) or sixth generation (6G) network or of a network beyond 6G wireless networks. An example representation of system 100 is shown depicting user device 200 in serving cell 230, serving network node device 210 in serving cell 230, and candidate network node devices 220A-220C in candidate cells 240A-240C. At least in some embodiments, the network of radio access network cell 110 may be comprised in a massive machine-to-machine (M2M) network, massive machine type communications (mMTC) network, internet of things (loT) network, industrial internet-of-things (lloT) network, enhanced mobile broadband (eMBB) network, ultra-reliable low-latency communication (URLLC) network, and / or the like. In other words, the network of radio access network cell 110 may be configured to serve diverse service types and / or use cases, and it may logically be seen as comprising one or more networks.

[0032] User device 200 may include, e.g., a mobile phone, a smartphone, a tablet computer, a smart watch, or any hand-held, portable and / or wearable device. User device 200 may also be referred to as a user equipment (UE). Network node devices 210, 220A- 220C may comprise, e.g., a base station or a transmission and reception point (TRP). The base station or TRP may include, e.g., any device suitable for providing an air interface for user devices to connect to a wireless network via wireless transmissions.

[0033] In the following, various example embodiments will be discussed. At least some of these example embodiments described herein may allow enhanced cell switch condition evaluation in lower layer triggered mobility. Furthermore, at least some of the example embodiments described herein may allow using measurements (for example, L1 / L2 / L3 measurements) to rank frequency layers, carriers, cells or reference signals (RSs) for which an LTM / CLTM condition evaluation is performed.

[0034] It is to be noted that herein the term LTM is used in a broad sense to refer both to conditional LTM (i.e. , CLTM) and non-conditional LTM (i.e., LTM).

[0035] Fig. 2A is a block diagram of user device 200, in accordance with an example embodiment.

[0036] User device 200 comprises one or more processors 202 and one or more memories 204 that comprise computer program code. User device 200 may also include other elements, such as transceiver 206 configured to enable user device 200 to transmit and / or receive information to / from other devices, as well as other elements not shown in Fig. 2A. In one example, user device 200 may use transceiver 206 to transmit or receive signalling information and data in accordance with at least one cellular communication protocol. Transceiver 206 may be configured to provide at least one wireless radio connection, such as for example a 3GPP mobile broadband connection (e.g., 5G or 6G). Transceiver 206 may comprise, or be configured to be coupled to, at least one antenna to transmit and / or receive radio frequency signals.

[0037] Although user device 200 is depicted to include only one processor 202, user device 200 may include more processors. In an embodiment, memory 204 is capable of storing instructions, such as an operating system and / or various applications. Furthermore, memory 204 may include a storage that may be used to store, e.g., at least some of the information and data used in the disclosed embodiments.

[0038] Furthermore, processor 202 is capable of executing the stored instructions. In an embodiment, processor 202 may be embodied as a multi-core processor, a single core processor, or a combination of one or more multi-core processors and one or more single core processors. For example, processor 202 may be embodied as one or more of various processing devices, such as a coprocessor, a microprocessor, a controller, a digital signal processor (DSP), a processing circuitry with or without an accompanying DSP, or various other processing devices including integrated circuits such as, for example, an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), a microcontroller unit (MCU), a hardware accelerator, a special-purpose computer chip, a neural network (NN) chip, an artificial intelligence (Al) accelerator, a tensor processing unit (TPU), a neural processing unit (NPU), or the like. In an embodiment, processor 202 may be configured to execute hard-coded functionality. In an embodiment, processor 202 is embodied as an executor of software instructions, wherein the instructions may specifically configure processor 202 to perform the algorithms and / or operations described herein when the instructions are executed.

[0039] Memory 204 may be embodied as one or more volatile memory devices, one or more non-volatile memory devices, and / or a combination of one or more volatile memory devices and non-volatile memory devices. For example, memory 204 may be embodied as semiconductor memories (such as mask ROM, PROM (programmable ROM), EPROM (erasable PROM), flash ROM, RAM (random access memory), etc.

[0040] User device 200 may comprise any of various types of devices used directly by an end user entity and capable of communication in a wireless network, such as a user equipment (UE). Such devices include but are not limited to smartphones, tablet computers, smart watches, lap top computers, internet-of-things (loT) devices, massive machine-to- machine (M2M) devices, massive machine type communications (mMTC) devices, industrial internet-of-things (lloT) devices, enhanced mobile broadband (eMBB) devices, ultrareliable low-latency communication (URLLC) devices, relay nodes (such as integrated access and backhaul nodes) configured to facilitate backhaul connections, and / or devices mounted in vehicles, etc.

[0041] When executed by at least one processor 202, instructions stored in at least one memory 204 cause user device 200 at least to transmit a candidate cell evaluation capability indication to serving network node 210 in serving cell 230 in preparation for a lower-layer (for example, L1 and / or L2) triggered mobility (LTM) -based cell switch from serving cell 230 to target cell.

[0042] The target cell is to be selected from multiple candidate cells 240A-240C. The candidate cell evaluation capability indication indicates a candidate cell evaluation capability of user device 200.

[0043] For example, the candidate cell evaluation capability of user device 200 may further indicate a maximum number of conditional LTM -based cell switch associated resources (for example, beams, frequency layers / carriers, cells, or RSs) that user device 200 is capable of evaluating.

[0044] The instructions, when executed by at least one processor 202, further cause user device 200 at least to receive candidate cell configuration information from serving network node 210.

[0045] At least in some embodiments, the instructions, when executed by at least one processor 202, may further cause user device 200 to receive the candidate cell configuration information from serving network node 210 via radio resource control (RRC).

[0046] For example, the candidate cell configuration information may comprise an indication of allowing user device 200 to perform the selection of the subset of multiple candidate cells 240A-240C or the associated beams. The instructions, when executed by at least one processor 202, further cause user device 200 at least to select, based at least on the indicated candidate cell evaluation capability of user device 200 and the received candidate cell configuration information, a subset of multiple candidate cells 240A-240C or associated beams for evaluating one or more LTM -based cell switch related evaluation conditions.

[0047] For example, the received candidate cell configuration information may comprise the one or more LTM -based cell switch related evaluation conditions.

[0048] At least in some embodiments, the instructions, when executed by at least one processor 202, may further cause user device 200 to perform radio resource measurements for multiple candidate cells 240A-240C.

[0049] At least in some embodiments, the instructions, when executed by at least one processor 202, may further cause user device 200 to perform the selection of the subset of multiple candidate cells 240A-240C or the associated beams further based on results of the performed radio resource measurements.

[0050] At least in some embodiments, the instructions, when executed by at least one processor 202, may further cause user device 200 to evaluate the one or more LTM - based cell switch related evaluation conditions only for the selected subset of multiple candidate cells 240A-240C or associated beams.

[0051] At least in some embodiments, the instructions, when executed by at least one processor 202, may further cause user device 200 to select the target cell for the LTM -based cell switch from the selected subset of multiple candidate cells 240A-240C based on results of the evaluation of the one or more LTM -based cell switch related evaluation conditions.

[0052] At least in some embodiments, M may represent the maximum number of the conditional LTM -based cell switch associated radio resources user device 200 is capable of evaluating, and M may be smaller than N which may represent a number of the multiple candidate cells for which the radio resource measurements are to be performed. For example, M may be based on the candidate cell evaluation capability of user device 200. For another example, M may be specific to a measurement type of the radio resource measurements.

[0053] At least in some embodiments, the instructions, when executed by at least one processor 202, may further cause user device 200 to determine for which of N multiple candidate cells 240A-240C to perform the radio resource measurements.

[0054] At least in some embodiments, M may be defined by: a total number, Mtotai, of the LTM -based cell switch associated radio resources that user device 200 is capable of evaluating simultaneously; a number, Mintra, of intra-frequency LTM -based cell switch associated radio resources that user device 200 is capable of evaluating in an evaluation period; a number, Minter, of inter-frequency LTM -based cell switch associated radio resources that user device 200 is capable of evaluating in an evaluation period; a number, Minter-w / o-gap, of inter-frequency LTM -based cell switch associated radio resources that user device 200 is capable of evaluating without a gap, without an interruption, and / or within an active bandwidth part; or a number, Minter-with-gap, of inter-frequency LTM -based cell switch associated radio resources that user device 200 is capable of evaluating within a gap.

[0055] At least in some embodiments, the instructions, when executed by at least one processor 202, may further cause user device 200 to perform a re-selection of the results of the performed radio resource measurements by performing the evaluation only on M strongest measured candidate cells, such that for each of the M strongest measured candidate cells evaluation, the one or more LTM -based cell switch related evaluation conditions are evaluated.

[0056] At least in some embodiments, the instructions, when executed by at least one processor 202, may further cause user device 200 to transmit to serving network node 210 a measurement report comprising results of the performed radio resource measurements only for the selected candidate cells.

[0057] At least in some embodiments, the instructions, when executed by at least one processor 202, may further cause user device 200 to perform the selection before the transmitting of the measurement report. Alternatively, the instructions, when executed by at least one processor 202, may further cause user device 200 to perform the selection after the transmitting of the measurement report.

[0058] At least in some embodiments, the instructions, when executed by at least one processor 202, may further cause user device 200 to start to perform the evaluation of the conditional LTM -based cell switch for a candidate cell of the selected subset of multiple candidate cells 240A-240C: after transmitting an initial event-based report for the candidate cell of the selected subset of multiple candidate cells 240A-240C; after starting a transmission of a measurement report for the candidate cell of the selected subset of multiple candidate cells 240A-240C; when serving cell 230 goes below a threshold; when transmitting a report indicating a low signal strength for serving cell 230; or after starting a beam failure detection or a T310 timer. To summarize, the above-described selection operation may be based on configured RSRP / RSRQ thresholds, or it may be based on ranking of the cells in signal strength order, or a combination of both. The performing of the selection may be associated with a measurement reporting event (for example, periodical or event-triggered), for example as follows:

[0059] - user device 200 may perform the selection procedure (of the subset) without transmitting a measurement report to the network;

[0060] - user device 200 may perform the selection procedure (of the subset) after it has transmitted a measurement report to the network;

[0061] - user device 200 may perform the selection operation (of the subset), and once the selection is performed, transmit a measurement report to the network. The measurement report may indicate the cells which have been selected. For instance, the cells may be transmitted in priority order based on conditional LTM evaluation conditions, or in the order of signal strength. For instance, only the cell(s) that are selected may be reported; and / or

[0062] - the measurements may be filtered measurements or unfiltered (based on less samples, e.g. 1 or 2 samples) measurements, and the reporting may be L1 / L2 / L3 reporting, for example. For example, L2 reporting may be MAC control element -based, and L3 reporting may be Radio Resource Control ASN.1 format -based.

[0063] In other words, user device 200 may perform measurements (e.g., RSRP and / or RSRQ) and based on the performed measurements, user device 200 may select / de- termine the beams, frequency layers / carriers, cells, or RSs to evaluate further. The cells that have not been selected may not be evaluated, hence power may be saved. In other words, the cells that are selected would be required to be evaluated by user device 200.

[0064] The (maximum) number of components to evaluate may be indicated, e.g., in a suitable specification, or user device 200 may signal its’ capability to serving network node 210. The M, or maximum required number may also be specified in user device requirements, in which case the number is the same across all of the user devices supporting the feature. In this case, the capability signalling may indicate support for the capability but may not necessarily indicate how many cells a user device is supporting as this would be indicated by the user device requirements (for instance, TS 38.133).

[0065] In an embodiment, the above-described measurement condition evaluation may be triggered by a measurement report, or the condition evaluation for the selected cells may be performed before transmitting the measurement report. For instance, periodic or event-triggered reporting may be used. That is, user device 200 may transmit a measurement report, and then the condition evaluation may be triggered. In an embodiment, user device 200 may transmit a measurement report of only those cells that are being evaluated. For example, user device 200 may select from eight cells two cells based on a selection criteria, and transmit a measurement report of those two cells.

[0066] In an embodiment, user device 200 may start the evaluation of a candidate cell after an initial (or first) event-based report is sent for that candidate cell. The eventbased report may be of a specific type, such as: event LTM2: beam of the serving cell becomes worse than an absolute threshold, event LTM3: beam of the candidate cell becomes better than the beam of the serving cell by an offset amount, event LTM4: beam of the candidate cell exceeds an absolute threshold, and / or event LTM5: beam of the serving cell becomes worse than an absolute thresholdl and the beam of the candidate cell becomes better than another absolute threshold2.

[0067] In an embodiment, user device 200 may start evaluating the execution condition after it starts sending a measurement report for that specific candidate cell or candidate beam. In an embodiment, user device 200 may start evaluating the execution condition if the serving cell goes below a threshold. In an embodiment, user device 200 may start evaluating the execution condition if user device 200 sends a report indicating low signal strength for the serving cell. In an embodiment, user device 200 may start evaluating the execution condition after beam failure detection or T310 timer is started.

[0068] For instance, when there is a difference between measurement configuration and how many evaluations user device 200 is able to perform based on capability, user device 200 may determine (e.g., select based on RSRP strength) which subset of candidate cells to evaluate.

[0069] In an embodiment, user device 200 may order and select the cells / RSs to measure on a per-cell or per-RS basis.

[0070] In an embodiment, user device 200 may configured with N (the number of candidate cells / RSs to measure with, e.g., L3 measurements), but user device 200 may decide or the user device 200 may be capable or required to only track (i.e. evaluate) M number of cells.

[0071] M may be based on one or more user device 200 -indicated capabilities, and M may be specific to a measurement type so there may be Mtotai, Mintra , Minter, Minter-w / o-gap, and / or Minter -with-gap.

[0072] Based on M number, user device 200 may perform periodic filtering (e.g. selection) of the subset of at least one candidate cell / RS. The filtering may be based on, e.g.:

[0073] - user device 200 selecting the M strongest (i.e., the best) L3-measured candidate cells out of all candidate cells and evaluating only these candidate cells. For each selected candidate cell, user device 200 may evaluate conditions associated with a (preconfigured (maximum) number of RSs, e.g., the user device 200 may evaluate conditions associated with four beams per candidate cell; or

[0074] - user device 200 selecting the M strongest L3 measured RSs out of all candidate cells and evaluating only the conditions associated with these RSs. For example, if the number of configured candidate cells is N=4, and the M=3, user device 200 may select three RSs from candidate cell 1 and one RS from candidate cell 2. In another example, if M=3, user device 200 may select, e.g., based on L3 measurements, the strongest candidate cell and evaluate three beam level evaluation conditions. In yet another example, user device 200 may select two cells, e.g., based on L3 measurements, and evaluate two beam level conditions from one cell and one beam level condition from another selected cell. In yet another example, user device 200 may select three candidate cells (M=3), and evaluate one cell level condition in each cell out of total four cells (N=4).

[0075] In an embodiment, user device 200 may be configured to be monitoring X number of conditional execution conditions versus Y event based reporting configurations for LTM and Z periodic reporting configurations. In this example, user device 200 may select Mtotal / Mintra , / Minter, / Minter -w / o-gap Minter-with-gap candidate cells / RSs so that the total number of candidate cells does not exceed user device 200 capability for evaluation.

[0076] In an embodiment, user device 200 may be configured with conditional LTM. For example, user device 200 may be configured to start evaluating the condition after the initial LTM based event reporting. The LTM based report may be configured to be a specific type, such as LTM3 or LTM5. User device 200 may be configured to start evaluating the condition after serving cell link quality degrades. User device 200 may report that serving cell 230 degrades below a threshold after which it may start evaluating the conditional LTM condition. User device 200 may start beam failure detection or beam failure recovery and at the same time user device 200 may start evaluating the conditional LTM condition.

[0077] When executed by at least one processor 202, instructions stored in at least one memory 204 cause user device 200 at least to transmit a candidate cell evaluation capability indication to serving network node 210 in serving cell 230 in preparation for a lower-layer triggered mobility (LTM) -based cell switch from serving cell 230 to a target cell.

[0078] The target cell is to be selected from multiple candidate cells 240A-240C. The candidate cell evaluation capability indication indicates a candidate cell evaluation capability of the user device 200.

[0079] For example, the candidate cell evaluation capability of user device 200 may further indicate a maximum number of conditional LTM -based cell switch associated resources (for example beams, frequency layers, carriers, cells, and / or RSs) that user device 200 is capable of evaluating. The instructions, when executed by at least one processor 202, further cause user device 200 at least to receive from serving network node 210 candidate cell configuration information and an indication of a subset of multiple candidate cells 240A- 240C to select.

[0080] The instructions, when executed by at least one processor 202, further cause user device 200 at least to select a subset of multiple candidate cells 240A-240C or associated beams for evaluating one or more LTM -based cell switch related evaluation conditions based at least on the received indication of the subset of multiple candidate cells 240A-240C to select.

[0081] For example, the received candidate cell configuration information may comprise the one or more LTM -based cell switch related evaluation conditions.

[0082] At least in some embodiments, the instructions, when executed by at least one processor 202, may further cause user device 200 to perform radio resource measurements (for example, L1 / L2 / L3 measurements, such as reference signal received power (RSRP) and / or reference signal received quality (RSRQ)) for multiple candidate cells 240A- 240C.

[0083] At least in some embodiments, the instructions, when executed by at least one processor 202, may further cause user device 200 to transmit a measurement report comprising results of the performed radio resource measurements to serving network node 210.

[0084] For example, the indicated subset of the multiple candidate cells 240A-240C to select may be based on the transmitted measurement report.

[0085] At least in some embodiments, the instructions, when executed by at least one processor 202, may further cause user device 200 to evaluate the one or more LTM - based cell switch related evaluation conditions only for the selected subset of multiple candidate cells 240A-240C or associated beams.

[0086] At least in some embodiments, the instructions, when executed by at least one processor 202, may further cause user device 200 to select the target cell for the LTM -based cell switch from the selected subset of multiple candidate cells 240A-240C based on results of the evaluation of the one or more LTM -based cell switch related evaluation conditions.

[0087] At least in some embodiments, the indication of the subset of multiple candidate cells 240A-240C to select may comprise an ordered list of the subset of multiple candidate cells 240A-240C to select.

[0088] At least in some embodiments, user device 200 may be capable of evaluating the maximum number, M, of the LTM -based cell switch associated resources, and the instructions, when executed by at least one processor 202, may further cause user device 200 to perform the evaluation of the one or more LTM -based cell switch related evaluation conditions only for LTM -based cell switch associated resources related to first M candidate cells of the received ordered list.

[0089] In other words, serving network node 210 may indicate to user device 200 which one or more cells / RSs it wants the user device 200 to evaluate. This may be used together with user device 200 capability indication. For example, if user device 200 is capable of M number of frequency layers, serving network node 210 may transmit a dedicated or existing list of candidate cells in an ordered manner to assist user device 200 in the selection of the evaluation.

[0090] Serving network node 210 may order the cells / RSs based on user device 200 reported value, or on a ranking based on serving network node 210 implementation (e.g., user device 200 report and serving network node 210 criteria).

[0091] The above-described network-assisted evaluation of M candidates based on an L3 measurement report may include at least some of the following.

[0092] In an embodiment, serving network node 210 may assist condition evaluation by user device 200 by transmitting an ordered list to user device 200 with candidate cells to evaluate. Serving network node 210 may order the list based on the received measurement report (e.g., L1 / L2 / L3 measurement report). Upon receiving the ordered list transmitted by serving network node 210, user device 200 may evaluate M first cells / carri- ers / RSs.

[0093] For example, serving network node 210 may transmit an updated list, or a new list of candidate cells based on user device 200 transmitted L3 measurement report (e.g., a list of candidate identifiers (IDs) to perform the condition evaluation). The list may be an ordered list of candidate cells (e.g., an existing candidate cell list ranked based on an L3 measurement report), and user device 200 may apply M candidates based on that list. The list may be a conditional LTM event evaluation list which is ordered based on an L3 measurement report, or based on other serving network node 210 -based criteria. The list may be a dedicated list for event evaluation. When the list is an out-of-order list, the list may be limited to M number of candidate IDs. When the list is an in-order list, the list may include more than M candidate cells, and user device 200 may only evaluate M candidate cells.

[0094] Fig. 3A illustrates an example signalling diagram of method 300A, in accordance with an example embodiment.

[0095] At optional operation 301 , in preparation for the LTM -based cell switch from serving cell 230 to a target cell to be selected from multiple candidate cells 240A-240C, user device 200 may receive a candidate cell evaluation capability request from serving network node 210 in serving cell 230, the candidate cell evaluation capability request requesting an indication of the candidate cell evaluation capability of user device 200. At operation 302, user device 200 transmits the candidate cell evaluation capability indication to serving network node 210 in serving cell 230, the candidate cell evaluation capability indication indicating the candidate cell evaluation capability of user device 200.

[0096] At optional operation 303, user device 200 may transmit, e.g., an L3 measurement report to serving network node 210, based on network transmitted synchronization signal blocks, similar to 305-307.

[0097] At operation 304, user device 200 receives the candidate cell configuration information from serving network node 210

[0098] At optional operations 305-307, user device 200 may receive reference signals, such as periodic synchronization signal blocks (SSBs), from network nodes 210, 220A-220C (only 220A-220B shown in Fig. 3A for clarity). The L3 measurements of operation 303 may be based on similar or same reference signals as the reference signals of steps 305-307. The L3 measurements of operation 303 may be used in configuring user device 200, to assist in generating a candidate list based on which the selection (e.g., in operation 308A) may be performed. Operations 305-307 may then be used in connection with the candidate cell list. In some embodiments, user device may be configured to use the same measurements from operation 303 to perform the selection procedure.

[0099] At operation 308A, user device 200 selects the subset of multiple candidate cells 240A-240C or the associated beams for evaluating the one or more LTM -based cell switch related evaluation conditions based at least on the indicated candidate cell evaluation capability of user device 200 and the received candidate cell configuration information. Additionally, user device 200 may perform the radio resource measurements for multiple candidate cells 240A-240C, for example, based on the reference signals received at optional operations 305-307, in which case the selection of the subset of multiple candidate cells 240A-240C or the associated beams may further be performed based on the results of the performed radio resource measurements.

[0100] At optional operation 309, user device 200 may evaluate the one or more LTM -based cell switch related evaluation conditions only for the selected subset of multiple candidate cells 240A-240C or the associated beams.

[0101] At optional operation 310, user device 200 may select the target cell (from device 220A in the example of Fig. 3A) for the LTM -based cell switch from the selected subset of multiple candidate cells 240A-240C based on results of the evaluation of the one or more LTM -based cell switch related evaluation conditions. User device 200 may further execute the cell switch to target cell 240A.

[0102] Embodiments and examples with regard to Fig. 3A may be carried out by user device 200 of Fig. 2A. Operations 301-310 may, for example, be carried out by at least one processor 202 and at least one memory 204. Further features of method 300A directly resulting from the functionalities and parameters of user device 200 are not repeated here. Method 300A can be carried out by computer program(s) or portions thereof.

[0103] Fig. 3B illustrates an example signalling diagram of method 300B, in accordance with an example embodiment.

[0104] Operations 301-307 are identical to those of Fig. 3A and thus are not repeated here.

[0105] At optional operation 308B1 , user device 200 may perform the radio resource measurements for multiple candidate cells 240A-240C, for example, based on the reference signals received at optional operations 305-307.

[0106] At optional operation 308B2, user device 200 may transmit to source network node 210 the measurement report comprising the results of the performed radio resource measurements. At this point, the measurement report may comprise measurement results of a number of cells (e.g. all of the candidate cells or, if the UE has already done the selection of the subset, only the selected candidate cells). When the network is aware that this the type of selection of the subset may be done, the network may be able to check the measurement report and already prepare a target cell, for instance.

[0107] At operation 308B3, user device 200 selects the subset of multiple candidate cells 240A-240C or the associated beams for evaluating the one or more LTM -based cell switch related evaluation conditions based at least on the indicated candidate cell evaluation capability of user device 200 and the received candidate cell configuration information, and optionally based on the results of the performed radio resource measurements.

[0108] Operations 309-310 are again identical to those of Fig. 3A and thus are not repeated here.

[0109] Embodiments and examples with regard to Fig. 3B may be carried out by user device 200 of Fig. 2A. Operations 301-310 may, for example, be carried out by at least one processor 202 and at least one memory 204. Further features of method 300B directly resulting from the functionalities and parameters of user device 200 are not repeated here. Method 300B can be carried out by computer program(s) or portions thereof.

[0110] Fig. 2B is a block diagram of serving network node device 210, in accordance with an example embodiment.

[0111] Serving network node device 210 comprises one or more processors 212 and one or more memories 214 that comprise computer program code. Serving network node device 210 may also include other elements, such as transceiver 216 configured to enable serving network node device 210 to transmit and / or receive information to / from other devices, as well as other elements not shown in Fig. 2B. In one example, serving network node device 210 may use transceiver 216 to transmit or receive signalling information and data in accordance with at least one cellular communication protocol. Transceiver 216 may be configured to provide at least one wireless radio connection, such as for example a 3GPP mobile broadband connection (e.g., 5G advanced or beyond). Transceiver 216 may comprise, or be configured to be coupled to, at least one antenna to transmit and / or receive radio frequency signals.

[0112] Although serving network node device 210 is depicted to include only one processor 212, serving network node device 210 may include more processors. In an embodiment, memory 214 is capable of storing instructions, such as an operating system and / or various applications. Furthermore, memory 214 may include a storage that may be used to store, e.g., at least some of the information and data used in the disclosed embodiments.

[0113] Furthermore, processor 212 is capable of executing the stored instructions. In an embodiment, processor 212 may be embodied as a multi-core processor, a single core processor, or a combination of one or more multi-core processors and one or more single core processors. For example, processor 212 may be embodied as one or more of various processing devices, such as a coprocessor, a microprocessor, a controller, a digital signal processor (DSP), a processing circuitry with or without an accompanying DSP, or various other processing devices including integrated circuits such as, for example, an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), a microcontroller unit (MCU), a hardware accelerator, a special-purpose computer chip, a neural network (NN) chip, an artificial intelligence (Al) accelerator, a tensor processing unit (TPU), a neural processing unit (NPU), or the like. In an embodiment, processor 212 may be configured to execute hard-coded functionality. In an embodiment, processor 212 is embodied as an executor of software instructions, wherein the instructions may specifically configure processor 212 to perform the algorithms and / or operations described herein when the instructions are executed.

[0114] Memory 214 may be embodied as one or more volatile memory devices, one or more non-volatile memory devices, and / or a combination of one or more volatile memory devices and non-volatile memory devices. For example, memory 214 may be embodied as semiconductor memories (such as mask ROM, PROM (programmable ROM), EPROM (erasable PROM), flash ROM, RAM (random access memory), etc.).

[0115] Serving network node device 210 may comprise a base station, and / or a relay node (such as an integrated access and backhaul node) configured to facilitate child (access) links for client devices connected to the relay node. The base station may include, e.g., a 5G advanced or 6G base station (gNB) or any such device providing an air interface for user device 200 to connect to a wireless network via wireless transmissions. When executed by at least one processor 212, instructions stored in at least one memory 214 cause serving network node device 210 at least to receive a candidate cell evaluation capability indication from user device 200 in serving cell 230 in preparation for a lower-layer triggered mobility (LTM) -based cell switch from serving cell 230 to a target cell.

[0116] The target cell is to be selected from multiple candidate cells 240A-240C. The candidate cell evaluation capability indication indicates a candidate cell evaluation capability of user device 200.

[0117] For example, the candidate cell evaluation capability of user device 200 may further indicate a maximum number of conditional LTM -based cell switch associated resources that user device 200 is capable of evaluating.

[0118] The instructions, when executed by at least one processor 212, further cause serving network node 210 at least to transmit to user device 200 candidate cell configuration information and an indication of a subset of multiple candidate cells 240A-240C to select.

[0119] For example, the transmitted candidate cell configuration information may comprise the one or more LTM -based cell switch related evaluation conditions.

[0120] At least in some embodiments, the instructions, when executed by at least one processor 212, may further cause serving network node 210 to receive from user device 200 a measurement report comprising results of radio resource measurements performed by user device 200.

[0121] At least in some embodiments, the instructions, when executed by at least one processor 212, may further cause serving network node 210 to determine the subset of multiple candidate cells 240A-240C to select based on the received measurement report.

[0122] At least in some embodiments, the indication of the subset of multiple candidate cells 240A-240C to select may comprise an ordered list of the subset of multiple candidate cells 240A-240C to select.

[0123] At least in some embodiments, the instructions, when executed by at least one processor 212, may further cause serving network node 210 to order the ordered list based on the received measurement report.

[0124] Further features of serving network node 210 directly result from the functionalities and parameters of user device 200 and thus are not repeated here.

[0125] Fig. 3C illustrates an example flow chart of method 300C, in accordance with an example embodiment.

[0126] At optional operation 301 , in preparation for the LTM -based cell switch from serving cell 230 to a target cell to be selected from multiple candidate cells 240A-240C, serving network node 210 in serving cell 230 may transmit the candidate cell evaluation capability request to user device 200 in serving cell 230, the candidate cell evaluation capability request requesting the indication of the candidate cell evaluation capability of user device 200. Further, the candidate cell evaluation capability request may be received by user device 200.

[0127] At operation 302, user device 200 transmits the candidate cell evaluation capability indication to serving network node 210, the candidate cell evaluation capability indication indicating the candidate cell evaluation capability of user device 200. Further, serving network node 210 receives the candidate cell evaluation capability indication.

[0128] At optional operation 303, user device 200 may transmit the L3 measurement report to serving network node 210. Further, serving network node 210 may receive the L3 measurement report.

[0129] At operation 304, serving network node 210 transmits the candidate cell configuration information to user device 200. Further, user device 200 receives the candidate cell configuration information.

[0130] At optional operations 305-307, user device 200 may receive reference signals from network nodes 210, 220A-220C (only 220A-220B shown in Fig. 3C for clarity).

[0131] At optional operation 308C1 , user device 200 may perform the radio resource measurements for multiple candidate cells 240A-240C, for example, based on the reference signals received at optional operations 305-307.

[0132] At optional operation 308C2, user device 200 may transmit to source network node 210 the measurement report comprising the results of the performed radio resource measurements. Further, the measurement report may be received by source network node 210. It is to be noted that operation 308C2 may alternatively be performed after operation 308C3 in which case the measurement report may comprise the results of the performed radio resource measurements only for the selected candidate cells.

[0133] At optional operation 308C3, source network node 210 may determine the subset of multiple candidate cells 240A-240C to select based on the received measurement report.

[0134] At operation 308C4, source network node 210 transmits to user device 200 the indication of the subset of multiple candidate cells 240A-240C to select (for example, the ordered list). Contents of the list may depend on, e.g., whether the list is a dedicated list or a full set of candidates. For example, in a first example implementation a new list may be used with only the subset that is selected. A second example implementation may use a legacy candidate list but reordered to allow serving network node 210 to help user device 200. Further, the indication of the subset of multiple candidate cells 240A-240C to select is received by user device 200. At operation 309C1 , user device 200 selects the subset of multiple candidate cells 240A-240C or the associated beams for evaluating the one or more LTM -based cell switch related evaluation conditions based at least on the received indication of the subset of multiple candidate cells 240A-240C to select. For example, when a full list is used, user device 200 may select the first M cells, for example. When a dedicated list is used, user device 200 may use a list of size M, for example.

[0135] At optional operation 309C2, user device 200 may evaluate the one or more LTM -based cell switch related evaluation conditions only for the selected subset of multiple candidate cells 240A-240C or the associated beams.

[0136] Operation 310 is again identical to those of Figs. 3A and 3B, and thus is not repeated here.

[0137] Embodiments and examples with regard to Fig. 3C may be carried out by user device 200 of Fig. 2A and serving network node device 210 of Fig. 2B. Operations 301-308C2, 308C4-310 may, for example, be carried out by at least one processor 202 and at least one memory 204. Operations 301-307, 308C2-308C4, 310 may, for example, be carried out by at least one processor 212 and at least one memory 214. Further features of method 300C directly resulting from the functionalities and parameters of user device 200 and network node device 210 are not repeated here. Method 300C can be carried out by computer program(s) or portions thereof.

[0138] The functionality described herein can be performed, at least in part, by one or more computer program product components such as software components. According to an embodiment, user device 200 and / or serving network node device 210 may comprise a processor or processor circuitry, such as for example a microcontroller, configured by the program code when executed to execute the embodiments of the operations and functionality described. Alternatively, or in addition, the functionality described herein can be performed, at least in part, by one or more hardware logic components. For example, and without limitation, illustrative types of hardware logic components that can be used include Field-programmable Gate Arrays (FPGAs), Application-specific Integrated Circuits (ASICs), Application-specific Standard Products (ASSPs), System-on-a-chip systems (SOCs), Complex Programmable Logic Devices (CPLDs), Tensor Processing Units (TPUs), and Graphics Processing Units (GPUs).

[0139] Any range or device value given herein may be extended or altered without losing the effect sought. Also, any embodiment may be combined with another embodiment unless explicitly disallowed.

[0140] Although the subject matter has been described in language specific to structural features and / or acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as examples of implementing the claims and other equivalent features and acts are intended to be within the scope of the claims.

[0141] It will be understood that the benefits and advantages described above may relate to one embodiment or may relate to several embodiments. The embodiments are not limited to those that solve any or all of the stated problems or those that have any or all of the stated benefits and advantages. It will further be understood that reference to 'an' item may refer to one or more of those items.

[0142] The steps of the methods described herein may be carried out in any suitable order, or simultaneously where appropriate. Additionally, individual blocks may be deleted from any of the methods without departing from the spirit and scope of the subject matter described herein. Aspects of any of the embodiments described above may be combined with aspects of any of the other embodiments described to form further embodiments without losing the effect sought.

[0143] The term 'comprising' is used herein to mean including the method, blocks or elements identified, but that such blocks or elements do not comprise an exclusive list and a method or apparatus may contain additional blocks or elements.

[0144] The term “non-transitory,” as used herein, is a limitation of the medium itself (i.e., tangible, not a signal) as opposed to a limitation on data storage persistency (e.g., RAM vs. ROM).

[0145] It will be understood that the above description is given by way of example only and that various modifications may be made by those skilled in the art. The above specification, examples and data provide a complete description of the structure and use of exemplary embodiments. Although various embodiments have been described above with a certain degree of particularity, or with reference to one or more individual embodiments, those skilled in the art could make numerous alterations to the disclosed embodiments without departing from the spirit or scope of this specification.

Claims

CLAIMS:1 . A user device, comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the user device at least to: in preparation for a lower-layer triggered mobility, LTM, -based cell switch from a serving cell to a target cell, the target cell to be selected from multiple candidate cells, transmit a candidate cell evaluation capability indication to a serving network node in the serving cell, the candidate cell evaluation capability indication indicating a candidate cell evaluation capability of the user device; receive from the serving network node candidate cell configuration information and an indication of a subset of the multiple candidate cells to select; and based at least on the received indication of the subset of the multiple candidate cells to select, select a subset of the multiple candidate cells or associated beams for evaluating one or more LTM -based cell switch related evaluation conditions.

2. The user device according to claim 1 , wherein the candidate cell evaluation capability of the user device further indicates a maximum number of conditional LTM - based cell switch associated resources that the user device is capable of evaluating.

3. The user device according to claim 1 or 2, wherein the received candidate cell configuration information comprises the one or more LTM -based cell switch related evaluation conditions.

4. The user device according to any of claims 1 to 3, wherein the instructions, when executed by the at least one processor, further cause the user device to perform radio resource measurements for the multiple candidate cells.

5. The user device according to claim 4, wherein the instructions, when executed by the at least one processor, further cause the user device to transmit a measurement report comprising results of the performed radio resource measurements to the serving network node.

6. The user device according to claim 5, wherein the indicated subset of the multiple candidate cells to select is based on the transmitted measurement report.

227. The user device according to any of claims 1 to 6, wherein the instructions, when executed by the at least one processor, further cause the user device to evaluate the one or more LTM -based cell switch related evaluation conditions only for the selected subset of the multiple candidate cells or associated beams.

8. The user device according to claim 7, wherein the instructions, when executed by the at least one processor, further cause the user device to select the target cell for the LTM -based cell switch from the selected subset of the multiple candidate cells based on results of the evaluation of the one or more LTM -based cell switch related evaluation conditions.

9. The user device according to any of claims 7 to 8, wherein the indication of the subset of the multiple candidate cells to select comprises an ordered list of the subset of the multiple candidate cells to select.

10. The user device according to claim 9, wherein the user device is capable of evaluating the maximum number, M, of the LTM -based cell switch associated resources, and the instructions, when executed by the at least one processor, further cause the user device to perform the evaluation of the one or more LTM -based cell switch related evaluation conditions only for LTM -based cell switch associated resources related to first M candidate cells of the received ordered list.

11. A method, comprising: in preparation for a lower-layer triggered mobility, LTM, -based cell switch from a serving cell to a target cell, the target cell to be selected from multiple candidate cells, transmitting from a user device a candidate cell evaluation capability indication to a serving network node in the serving cell, the candidate cell evaluation capability indication indicating a candidate cell evaluation capability of the user device; receiving at the user device from the serving network node candidate cell configuration information and an indication of a subset of the multiple candidate cells to select; and based at least on the received indication of the subset of the multiple candidate cells to select, selecting, by the user device, a subset of the multiple candidate cells or associated beams for evaluating one or more LTM -based cell switch related evaluation conditions.

12. A non-transitory computer readable medium comprising program instructions that, when executed by a user device, cause the user device to perform at least the following: in preparation for a lower-layer triggered mobility, LTM, -based cell switch from a serving cell to a target cell, the target cell to be selected from multiple candidate cells, transmitting a candidate cell evaluation capability indication to a serving network node in the serving cell, the candidate cell evaluation capability indication indicating a candidate cell evaluation capability of the user device; receiving from the serving network node candidate cell configuration information and an indication of a subset of the multiple candidate cells to select; and based at least on the received indication of the subset of the multiple candidate cells to select, selecting a subset of the multiple candidate cells or associated beams for evaluating one or more LTM -based cell switch related evaluation conditions.

13. A serving network node in a serving cell, comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the serving network node at least to: in preparation for a lower-layer triggered mobility, LTM, -based cell switch from a serving cell to a target cell, the target cell to be selected from multiple candidate cells, receive a candidate cell evaluation capability indication from a user device in the serving cell, the candidate cell evaluation capability indication indicating a candidate cell evaluation capability of the user device; and transmit to the user device candidate cell configuration information and an indication of a subset of the multiple candidate cells to select.

14. The serving network node according to claim 13, wherein the candidate cell evaluation capability of the user device further indicates a maximum number of conditional LTM -based cell switch associated resources that the user device is capable of evaluating.

15. The serving network node according to claim 13 or 14, wherein the transmitted candidate cell configuration information comprises the one or more LTM -based cell switch related evaluation conditions.

16. The serving network node according to any of claims 13 to 15, wherein the instructions, when executed by the at least one processor, further cause the servingnetwork node to receive from the user device a measurement report comprising results of radio resource measurements performed by the user device.

17. The serving network node according to claim 16, wherein the instructions, when executed by the at least one processor, further cause the serving network node to determine the subset of the multiple candidate cells to select based on the received measurement report.

18. The serving network node according to any of claims 13 to 17, wherein the indication of the subset of the multiple candidate cells to select comprises an ordered list of the subset of the multiple candidate cells to select.

19. The serving network node according to any of claims 16 to 18, wherein the instructions, when executed by the at least one processor, further cause the serving network node to order the ordered list based on the received measurement report.

20. A method, comprising: in preparation for a lower-layer triggered mobility, LTM, -based cell switch from a serving cell to a target cell, the target cell to be selected from multiple candidate cells, receiving at a serving network node a candidate cell evaluation capability indication from a user device in the serving cell, the candidate cell evaluation capability indication indicating a candidate cell evaluation capability of the user device; and transmitting from the serving network node to the user device candidate cell configuration information and an indication of a subset of the multiple candidate cells to select.

21. A non-transitory computer readable medium comprising program instructions that, when executed by a serving network node, cause the serving network node to perform at least the following: in preparation for a lower-layer triggered mobility, LTM, -based cell switch from a serving cell to a target cell, the target cell to be selected from multiple candidate cells, receiving a candidate cell evaluation capability indication from a user device in the serving cell, the candidate cell evaluation capability indication indicating a candidate cell evaluation capability of the user device; and transmitting to the user device candidate cell configuration information and an indication of a subset of the multiple candidate cells to select.25

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