Measurement resource configuration for secondary cell measurements

Abstract

Methods for handling measurements of cells associated with Layer-1 / Layer-2-triggered mobility, LTM, in a wireless network. In example method, a user equipment, UE, receives, from a network node in the wireless network, measurement information specifying one or more measurement resources for one or more secondary cells, SCells. The one or more SCells are in a same group as an LTM candidate cell configured for the UE, and the one or more SCells are not configured as LTM candidate cells for the UE. The UE performs Layer-1 measurements on at least one of the measurement resources for at least one of the one or more SCells.

Description

[0001] MEASUREMENT RESOURCE CONFIGURATION FOR SECONDARY CELL MEASUREMENTS

[0002] TECHNICAL FIELD

[0003] The present application relates generally to the field of wireless networks, and more specifically to improving mobility of user equipment (UEs) across multiple cells in a wireless network, specifically mobility based on layer-1 (L1 ) and / or layer-2 (L2) procedures that incur less delay than conventional layer-3 mobility procedures.

[0004] BACKGROUND

[0005] Currently the fifth generation (5G) of cellular systems is being standardized within the Third-Generation Partnership Project (3GPP). This includes a radio network technology widely known as “NR” (from “New Radio”). NR is developed for maximum flexibility to support multiple and substantially different use cases. These include enhanced mobile broadband (eMBB), machine type communications (MTC), ultra-reliable low latency communications (URLLC), side-link device-to-device (D2D), and several other use cases.

[0006] Figure 1 illustrates a high-level view of an exemplary 5G network architecture, consisting of a Next Generation Radio Access Network (NG-RAN, 199) and a 5G Core (5GC, 198). The NG-RAN can include one or more gNodeBs (gNBs) connected to the 5GC via one or more NG interfaces, such as gNBs (100, 150) connected via respective interfaces (102, 152). More specifically, the gNBs can be connected to one or more Access and Mobility Management Functions (AMFs) in the 5GC via respective NG-C interfaces and to one or more User Plane Functions (UPFs) in 5GC via respective NG-U interfaces. The 5GC can include various other network functions (NFs), such as Session Management Function(s) (SMF).

[0007] Although not shown in Figure 1 , in some deployments the 5GC can be replaced by an Evolved Packet Core (EPC), which conventionally has been used together with a fourth generation (4G) Long-Term Evolution (LTE) Evolved UMTS RAN (E-UTRAN). In such deployments, gNBs (e.g., 100,150) can connect to one or more Mobility Management Entities (MMEs) in EPC 198 via respective S1-C interfaces. Similarly, gNBs can connect to one or more Serving Gateways (SGWs) in EPC via respective NG-U interfaces.

[0008] In addition, the gNBs can be connected to each other via one or more Xn interfaces, such as Xn interface (140) between gNBs (100, 150). The radio technology for the NG-RAN is often referred to as “New Radio” (NR). With respect to the NR interface to UEs, each of the gNBs can support frequency division duplexing (FDD), time division duplexing (TDD), or a combination thereof. Each of the gNBs can serve a geographic coverage area including one or more cells and, in some cases, can also use various directional beams to provide coverage in the respective cells. In general, a DL “beam” is a coverage area of a network-transmitted reference signal (RS) that may be measured or monitored by a UE.

[0009] NG RAN logical nodes (e.g., gNB 100) include a Central Unit (CU or gNB-CU, e.g., 110) and one or more Distributed Units (DU or gNB-DU, e.g., 120, 130). CUs are logical nodes that host higher-layer protocols and perform various gNB functions such controlling the operation of DUs. DUs are decentralized logical nodes that host lower layer protocols and can include, depending on the functional split option, various subsets of the gNB functions. Each CU and DU can include various circuitry needed to perform their respective functions, including processing circuitry, communication interface circuitry (e.g., transceivers), and power supply circuitry.

[0010] A gNB-CU connects to one or more gNB-DUs over respective F1 logical interfaces (e.g., 122 and 132 shown in Figure 1). However, a gNB-DU can be connected to only a single gNB-CU. The gNB-CU and its connected gNB-DU(s) are only visible to other gNBs and the 5GC as a gNB. In other words, the F1 interface is not visible beyond gNB-CU.

[0011] In NR, measurement and reporting operations enable the network to dynamically configure a user equipment (UE) to use multiple cells, in a so-called Master Cell Group (MCG) and / or in aso-called Secondary Cell Group (SCG), for enhancing coverage, capacity, and mobility. Using measurement and reporting configurations signaled to the UE by the network, the UE performs measurements on neighboring cells, focusing on measurement metrics like reference signal received power (RSRP), reference signal received quality (RSRQ), and signal-to-interference-plus-noise ratio (SINR) to evaluate signal quality and interference levels.

[0012] These measurements performed by the UE are based on reference signals such as the Synchronization Signal Block (SSB), for initial synchronization, and Channel State Information Reference Signals (CSI-RS), for detailed channel state information. The network uses Radio Resource Control (RRC) signaling to configure the UE with measurement objects and reporting criteria. A measurement object specifies the target frequency of the cells to be measured, cell group information (MCG or SCG), reference signal information (SSB or CSI-RS), measurement types (e.g., RSRP, RSRQ, SINR) the UE needs to perform, and other relevant neighbor cell information. Reporting configurations define triggering events for sending measurement reporting, which can be event-based (e.g., based on threshold conditions) or periodic (at regular intervals).

[0013] For an MCG, measurement reports can be used by the network to help decide whether a neighboring cell should be added as a secondary cell (SCell), improving data rates and / or providing redundancy using carrier aggregation (CA). For SCG, in a Dual Connectivity (DC) scenario, reports guide the addition of SCG SCells, to enhance capacity or offload traffic from the MCG.

[0014] The UE sends measurement reports to the Master Node (MN) for MCG SCell measurements or to the Secondary Node (SN) for SCG SCell measurements. Upon receiving reports, the network evaluates signal quality and decides whether to add, modify, or remove SCells based on predefined thresholds and resource availability. The network activates SCells using RRC signaling, specifying carrier aggregation (CA) and / or dual connectivity settings for datatransmission. Dynamic updates allow the network to deactivate SCells with degrading signal quality or to replace them with better-performing neighbors. By leveraging UE measurement and reporting, 5G NR achieves efficient resource allocation, improved coverage, and seamless user mobility management.

[0015] Layer 1 / Layer 2-Triggered Mobility (LTM) has been specified in Release 18of the3GPP specifications as part of the Mobility enhancements Work Item. LTM is a procedure in which a gNB receives Layer 1 (L1 ) measurement report(s) from a UE, via lower layer signaling, where the term “lower layer signaling” as used herein refers to signaling at Layer 1 and / or Layer 2, i.e., below the Radio Resource Control layer. These L1-measurement reports are used by the network for mobility-related decisions, such as executing an LTM cell switch to a target cell by sending an LTM Cell Switch MAC Control Element (MAC CE) command. This cell switch command refers to an LTM candidate cell configuration that the gNB previously prepared and provided to the UE through RRC signalling. Upon receipt of the command, the UE switches to the target cell, according to the cell switch command. The LTM procedure can be used to reduce mobility latency.

[0016] LTM supports both intra-gNB-DU and intra-gNB-CU / inter-gNB-DU mobility. LTM supports both intra-frequency and inter-frequency mobility, including mobility to an inter-frequency cell that is not a current serving cell.

[0017] Figure 2 illustrates the signaling procedure for LTM. Some details of the illustrated steps are as follows:

[0018] 1. The UE sends L3-measurement report(s) to the gNB for one or more cells. Based on these reports, the gNB identifies and configures one or more cells as LTM candidate cells, initiating the LTM preparation phase.

[0019] 2. The gNB sends an RRC Reconfiguration message to the UE with the configuration details for the LTM candidate cells.3. The UE stores the received LTM candidate configurations and acknowledges with an RRC Reconfiguration Complete message.

[0020] 4a. Downlink ((DL) Pre-Synchronization: Optionally, the UE may perform early DL synchronization with LTM candidate cells upon receiving a "Candidate Cell transmission configuration indicator (TCI) States Activation / Deactivation MAC CE," reducing the mobility interruption by avoiding SSB-based synchronization after the cell switch.

[0021] 4b. UL Pre-Synchronization: If the UE receives a physical downlink control channel (PDCCH) order for early timing advance (TA) acquisition, it may also perform UL presynchronization with the candidate cells, further reducing the mobility delay.

[0022] 5. The UE performs L1 measurements on the configured LTM candidate cells and reports them to the source node.

[0023] 6. The source node decides the target cell for the switch and sends an “LTM Cell Switch” MAC CE containing the configuration index of the selected LTM cell. The UE switches to the target cell and applies the indicated configuration of the LTM candidate cell.

[0024] 7. If the UE lacks a valid TA value for the target cell, it performs a random-access procedure. If a valid TA was acquired earlier during early UL synchronization, this procedure is skipped. Moreover, if the target cell TCI state indicated in the LTM cell switch MAC CE differs from the pre-synchronized TCI state, additional synchronization may be required.

[0025] 8. The UE completes the LTM cell switch by sending an RRC Reconfiguration Complete message to the target cell. For cases involving random-access, successful completion of the random-access procedure confirms the switch. For RACH-less LTM, the switch is deemed successful once the network acknowledges the UE’s first UL data transmission. The UE determines successful reception of its first UL data by receiving a PDCCH addressing the UE’s C-RNTI in the target cell, which schedules a newtransmission following the first UL data. The PDCCH carries either a DL assignment or an UL grant addressing the same HARQ process as the first UL data.

[0026] As noted above, the LTM cell switch is driven by L1 measurements reported to the network by the UE. Release 18 of the 3GPP specifications for LTM specify measurement resource configuration for supporting L1-RSRP measurements on reference signals in LTM candidate cells. The information element (IE) illustrated in Figure 3 is an example of measurement information sent to the UE by the network, and defines a group of one or multiple measurement resources for one or more LTM candidate configurations.

[0027] As seen in Figure 3, the measurement resource configuration information element includes a measurement resource configuration identifier (ID) and a corresponding measurement resource set for the LTM configuration. Each measurement resource set includes a list of SSB indices and a list of the respective LTM candidate cell ID(s). According to Release 18 (Rel-18) versions of the 3GPP specifications, the UE performs L1-RSRP measurements on the LTM candidate cell SSBs. The ongoing development of Release 19 (Rel-19) versions of the specifications includes agreements related to the performance of L1-RSRP measurements by the UE on the LTM candidate cell CSI-RS, as well.

[0028] Rel-18 LTM defines four different types of measurement reporting related to the LTM procedures, e.g., early synchronization and LTM cell switch. The specific measurement reported desired by the network is configured in the UE by providing the UE with LTM reporting configuration information. In Rel-18 LTM, periodic reporting on physical uplink control channel (PUCCH), semi-persistent reporting on PUCCH, semi-persistent reporting on physical uplink shared channel (PUSCH), and aperiodic reporting methods are supported. Each of these measurement report types is carried via uplink control information (UCI). Figure 4 illustrates the information element used to configure the UE to use each of these reporting types.As indicated above, the periodic report in LTM can only be carried via PUCCH and the associated PUCCH resource configuration for report transmission, reporting periodicity, and offset are provided via RRC configuration in the serving cell. The semi-persistent report in LTM can be carried via PUSCH or PUCCH, and the transmission of semi-persistent report is activated via a MAC CE. Aperiodic reporting in LTM can only be carried via PUSCH and the transmission of the aperiodic LTM CSI report is polled via downlink control information (DCI).

[0029] SUMMARY

[0030] According to the current specifications for LTM, a UE performs L1 measurements and reporting only for LTM candidate cells, and not for SCells that might be in the same group (the MCG or SCG) as an LTM candidate cell. Layer 3 (L3) measurements and reporting may be performed for these SCells, and the reports may be used by the network to make decisions about activating, deactivating, or releasing SCells, but L3 measurement and reporting procedures utilize RRC signaling, which is much slower than the lower layer signaling used for L1 measurements and reporting. Consequently, it may not be possible for the network to simultaneously execute the configuration, activation, deactivation, or release decisions for SCells, while performing the LTM cell switch to one of the LTM candidate cells.

[0031] According to some embodiments, there is provided a method performed by a user equipment (UE). The method is for handling measurements of cells associated with LTM in a wireless network. The method comprises receiving, from a network node in the wireless network, measurement information specifying one or more measurement resources for one or more secondary cells (Scells). The one or more SCells are in a same group as an LTM candidate cell configured for the UE. The one or more Scells are not configured as LTM candidate cells for the UE. The method comprises performing L1 measurements on at least one of the measurement resources for at least one of the one or more SCells.According to some embodiments, there is provided a method performed by a first network node. The method is for handling measurements of cells associated with LTM in a wireless network. The method comprises sending, to a UE, measurement information specifying one or more measurement resources for one or more SCells. The one or more Scells are in a same group as an LTM candidate cell configured for the UE. The one or more SCells are not configured as LTM candidate cells for the UE.

[0032] According to some embodiments, there is provided a method performed by a second network node. The method is for handling measurements of cells associated with LTM in a wireless network. The method comprises receiving, from a first network node, a request for measurement information specifying one or more measurement resources for one or more secondary cells, SCells. The one or more SCells are in a same group as an LTM candidate cell configured for a user equipment, UE. The one or more SCells are not configured as LTM candidate cells for the UE. The method comprises sending, to the first network node, measurement information specifying at least one measurement resource for at least one SCell. Accordingto some embodiments, there is provided a User Equipment (UE). The UE comprises processing circuitry and communication interface circuitry configured to carry out the method performed by the UE as described herein.

[0033] Accordingto some embodiments, there is provided a first network node. The first network node comprises processing circuitry and communication interface circuitry configured to carryout the method performed by the first network node as described herein.

[0034] Accordingto some embodiments, there is provided a second network node. The second network node comprises processing circuitry and communication interface circuitry configured to carry out the method performed by the second network node as described herein.Embodiments of the methods, apparatuses, and systems described may be used to address this and related problems. These include methods implemented at the UE and the network to provide to the UE a measurement configuration in order to allow the UE to perform measurements on reference signals or beams of one or more Scells while the UE receives LTM candidate cell configuration. This may be done even for an SCell that is not configured as one of the LTM candidate cells. BRIEF DESCRIPTION OFTHE FIGURES

[0035] For better understanding of the embodiments of the present disclosure, and to show how it may be put into effect, reference will now be mase, by way of example only, to the accompanying drawings, in which:

[0036] Figure 1 shows a high-level view of an exemplary 5G network architecture.

[0037] Figure 2 illustrates the signaling procedure for LTM.

[0038] Figure 3 illustrates a Measurement Resource Configuration information element (IE) in 3GPP Release 18.

[0039] Figure 4 illustrates a reporting configuration IE in 3GPP Release 18.

[0040] Figure 5 illustrates SCell activation / deactivation upon LTM cell switch.

[0041] Figure 6 shows an exemplary method (e.g., procedure) fora UE, according to various embodiments of the present disclosure.

[0042] Figure? showsan exemplary method (e.g., procedure) fora network node, according to various embodiments of the present disclosure.

[0043] Figure 8 shows an exemplary method (e.g., procedure) for another network node, according to various embodiments of the present disclosure.Figure 9 shows a communication system according to various embodiments of the present disclosure.

[0044] Figure 10 shows a UE according to various embodiments of the present disclosure.

[0045] Figure 11 shows a network node according to various embodiments of the present disclosure.

[0046] Figure 12 is a block diagram of a virtualization environment in which functions implemented by some embodiments of the present disclosure may be virtualized.

[0047] DETAILED DESCRIPTION

[0048] This disclosure may use the term “L1 / L2 based inter-cell mobility” as used in the Work Item Description in 3GPP, though it interchangeably also uses the terms L1 / L2 mobility, L1 -mobility, L1 based mobility, L1 / L2-centric inter-cell mobility, L1 / L2 inter-cell mobility, Layer-1 / Layer-2-triggered Mobility, L1 / L2-Triggered Mobility, Lower-layer Triggered Mobility, or simply LTM. The basic principle of LTM is that the UE receives a lower layer signaling from the network indicating to the UE a change (or switch or activation) of its serving cell (e.g., change of PCell, from a source to a target Pcell) in accordance with configuration information previously received by the UE. A lower layer signaling is a message / signaling of a lower layer protocol, which may be referred as a L1 / L2 inter-cell mobility execution command or LTM cell switch command. The change of serving cell (e.g., change of Pcell) may also lead to a change in Scell(s) for the same cell group, e.g., in case the command triggers the UE to change to another cell group configuration of the same type (e.g. another MCG configuration). Before the UE receives the LTM cell switch command, the UE is configured by the network with one or more LTM candidate cell configurations (e.g., reception of an RRC Reconfiguration message, with at least one LTM candidate cell configuration). An LTM candidate cell configuration may include parameters in the IE CellGroupConfig per candidate cell and / or an embedded RRC Reconfiguration per LTM candidate cell.The term LTM cell switch procedure refers to the process of a UE changing its cell from a source cell to a target cell (which may be called here a candidate cell ora neighbor cell), using L1 / L2 triggered mobility (LTM). In the context of LTM execution or LTM cell switch, the text may refer to the serving cell before the LTM cell switch as source cell, old source cell, or previous source cell. An LTM cell switch procedure may sometimes also be known as dynamic switch, LTM switch, (LTM) cell switch, (LTM) serving cell change or (LTM) cell change, or LTM execution. Even if the term change of cell is used, that may comprise a change of a whole cell group configuration, which includes a change in the SpCell (e.g., change of PCell or change of PSCell) and a change in SCells of the cell group (e.g., addition, modification and / or release of one or more SCells). The LTM cell switch procedure may be triggered by the UE receiving an LTM cell switch command from the network. The source and target cells in a LTM cell switch procedure may be controlled by the same gNB, which sometimes is referred to as the intra-gNB case, or when the gNB uses a distributed CU / DU RAN architecture, the intra-CU inter-DU case or the intra-CU intra-DU case (dependingon whetherthe cells are controlled bythe same DU or different DUs). When the source and target cells in a LTM cell switch procedure are controlled by different gNBs, this is sometimes referred to as the inter-gNB case, or inter-CU case, or sometimes known as an inter-CU LTM cell switch procedure.

[0049] Where the term “change of cell” is used, the change of cell may comprise a change of a whole cell group configuration, which includes a change in the SpCell (e.g., change of Pcell, or change of PSCell) and a change in Scells of the cell group (e.g., addition, modification and / or release of one or more Scells).

[0050] An LTM cell switch procedure may be triggered in the UE by reception of a LTM cell switch command, e.g., a MAC CE.

[0051] This document often refers to an LTM candidate cell, which is a cell the UE is configured with when configured with L1 / L2-triggered mobility. That is, a cell the UE can move to in a LTM cellswitch procedure, upon reception of a LTM cell switch command. These cells may also be called candidate cell(s), candidates, mobility candidates, non-serving cells, additional cells, target candidate cell, target candidate, etc. A LTM candidate cell is a cell the UE performs measurements on (e.g., CSI measurements) so that the UE reports these measurements and the network may take educated decision on which beam (e.g. TCI state) and / or cell the UE is to be switched to. An LTM candidate cell may be a candidate to be a target Pcell or PSCell, or an Scell of a cell group (e.g. MCG Scell).

[0052] This disclosure also refers often to “at least one LTM candidate cell configuration” and may state that the UE has received at least one LTM candidate cell configuration. This is also sometimes referred to as a configuration of a LTM candidate cell, which may be an RRC configuration, such as encapsulated in an RRC Reconfiguration message, that the UE receives when being configured with L1 / L2-Triggered Mobility. A LTM candidate cell configuration may comprise the configuration the UE needs to start to operate accordingly when it performs an LTM cell switch procedure to that LTM candidate cell, e.g., upon reception of an LTM cell switch command indicating the UE to perform a LTM cell switch procedure to that LTM candidate cell, which becomes the target cell and the current (new) SpCell, or an SCell in a serving frequency. The LTM candidate cell configuration may comprise parameters of a serving cell (or multiple serving cells, such as a cell group), comprising one or more of the groups of parameters, such as an RRCReconfiguration message an IE CellGroupConfigor an IE SpCellConfig (or the IE SCellConfig, in the case of a Secondary Cell). A LTM candidate cell configuration may in one example comprise one or more of: i) the PCell configuration and one or more SCell configuration(s) of a Master Cell Group (MCG); i) the PSCell configuration and one or more SCell configuration(s) of a secondary Cell Group (SCG). The terms (LTM) candidate configuration, LTM configuration, (LTM) candidate target cell configuration, (LTM) target candidate (cell) configuration may be used interchangeably when referringto LTM candidate cell configuration. An LTM candidate cell configuration may be associated with an identifier which is used in thesignaling when referring to a certain LTM candidate cell configuration, such as when the UE receives the LTM candidate cell configuration and when the UE receives an LTM cell switch command indicating the UE to perform a LTM cell switch procedure to that LTM candidate cell. This identifier is sometimes known as the LTM candidate cell configuration identity or LTM candidate configuration index (or similar).

[0053] The text introduces the concept of Conditional LTM (CLTM), which can be viewed as a form of conditional reconfiguration, in which LTM cell switch is triggered in the UE by some other event, such as a condition, e.g., a triggering condition used for conditional configuration. In CLTM, the UE is configured with at least one LTM candidate cell (denoted as a CLTM candidate cell), by receiving an LTM candidate cell configuration, as in legacy LTM, and called herein a Conditional LTM candidate cell configuration, and an associated execution condition, denoted as CLTM execution condition. The evaluation of CLTM execution condition associated to a CLTM candidate cell may be performed by the assessment of lower layer measurements, such as Layer 1 reference signal received power (L1-RSRP) and / or SS-RSRP, derived from SSBs and / or CSI-RSs of either the source cell and / or an LTM candidate cell. Lower layer measurements, in this context, are measurements reported to support lower layer procedures like beam management, candidate cell TCI state activation / deactivation, early timing advance (TA) acquisition, and link adaptation, and they aren't filtered based on Layer 3 (L3) parameters, though there may or may not be some filtering of these measurements based on the other lower layer parameters. The reception of CLTM execution condition may also involve receiving an indication of the condition and / or configuring it with parameters such as event identifier(s), offset(s), threshold(s), RS type, trigger quantity such as RSRP, RSRQ or SINR, TTT, and so forth.

[0054] In the context of CLTM, the UE relies on evaluating one or two condition(s), referred to as CLTM execution condition(s), LTM execution condition(s), or triggering condition(s), or a combination thereof. And, when the condition(s) for a CLTM candidate cell is(are) fulfilled, the UE mayperform a cell switch, which may be seen as a kind of LTM execution which is not triggered by the reception of an LTM cell switch command; this may also be considered as a kind of LTM cell switch, or LTM cell switch execution, or Conditional LTM cell switch, or Conditional LTM execution, or CLTM execution, or simply cell switch. According to the methods outlined in the invention, upon satisfaction of the execution condition(s), the UE may initiate an LTM cell switch. The term LTM cell switch refers to the process of a UE changing its cell from a source cell to a target cell, using L1 / L2 triggered mobility (LTM). In the context of Conditional LTM execution, the text may refer to the serving cell before the LTM cell switch as source cell, old source cell, or previous source cell.

[0055] The text also discusses the concept of an LTM candidate cell within the framework of Conditional LTM. The candidate cell may be referred to as a CLTM candidate cell, CLTM cell, simply candidate cell, candidate target cell, simply target cell, LTM candidate cell, LTM cell, or L1 / L2 inter-cell mobility candidate cell, depending on the context or terminology used in the invention. Essentially, it denotes a cell to which the UE is directed or switches to in the event of executing a conditional L1 / L2 inter-cell mobility procedure after meeting the associated execution condition(s) and may also be termed as new source cell or next source cell after the LTM cell switch (or after LTM cell switch execution). These cells may also be termed as candidate cells, mobility candidates, non-serving cells, additional cells, candidate target cell, simply target cell or deactivated cells. In the context of the invention, performing the CLTM execution comprises the UE considering that the CLTM candidate cell becomes its new special cell (SpCell) e.g., PCell in case of CLTM being configured for a Master Cell Group (MCG) and / or PSCell in case of CLTM being configured for a Secondary Cell Group (SCG); or, changing its SpCell from the current PCell to a CLTM candidate cell.

[0056] The text uses the term “conditional LTM” or “conditional LTM candidate configuration” which is used to identify a configuration for which the UE is provided with certain criteria which the UEneeds to evaluate by itself. Upon the fulfillment of these one or more criteria the UE may execute autonomously a conditional LTM cell switch procedure and may apply the provided conditional LTM candidate configuration without the network indicating to do so. The text also uses the term “normal LTM” or “normal LTM candidate configuration” which is used to identify an LTM candidate configuration which the UE applies only upon receiving an indication from the network to trigger an LTM cell switch execution.

[0057] An LTM candidate cell might also pertain to a candidate cell in a 5G Radio Access Technology like NR or a future 6G Radio Access Technology.

[0058] The terms “triggering” the LTM cell switch or “executing” the LTM cell switch are used interchangeably in this disclosure.

[0059] An LTM cell switch procedure may alternatively be triggered in the UE upon the reception of LTM cell switch or by some other event, e.g., an event condition evaluated on L3 -RSRP for conditional configuration, such as conditional handover, being fulfilled, as a result of recovery from radio link failure or handover failure.

[0060] The term “CHO execution procedure” refers to the process of a UE evaluating certain criteria configured by the network and, upon the fulfilling of such criteria, the UE switching (orchanging) its cell from a source cell to a target cell without any network indication. In the context of the invention, switching to the CHO candidate configuration comprises the UE considering that the CHO candidate cell becomes its new special cell (SpCell) e.g., Pcell in case of CHO being configured for a Master Cell Group (MCG) and / or PSCell in case of CHO being configured for a Secondary Cell Group (SCG); or, changing its SpCell from the current PCell to an CHO candidate cell. Further, for the case when CHO is configured on the PSCell, this procedure may also be called as CPA, CPC, CPAC, or subsequent CPAC.Even if the term change of cell is used, that may comprise a change of a whole cell group configuration, which includes a change in the SpCell (e.g., change of PCell or change of PSCell) and a change in SCells of the cell group (e.g., addition, modification and / or release of one or more SCells).

[0061] The text refers to at least one LTM / CLTM candidate cell configuration or CHO candidate configuration and that the UE has received at least one LTM / CLTM candidate cell configuration or CHO candidate configuration. This is also sometimes referred to as a configuration of an LTM / CLTM candidate cell or CHO candidate, which may be an RRC configuration, such as encapsulated in an RRC Reconfiguration message, that the UE receives when being configured with L1 / L2-Triggered Mobility or CHO. An LTM / CLTM or CHO candidate cell configuration comprises the configuration that the UE needs to start to operate accordingly when it performs an LTM cell switch / CLTM execution or a CHO execution procedure to that candidate cell e.g., upon reception of the LTM cell switch command indicating the UE to perform an LTM cell switch procedure to that LTM candidate cell or when certain CLTM / CHO criteria have been fulfilled, which becomes the target cell and the current (new) SpCell, or an SCell in a serving frequency. The LTM / CLTM or CHO candidate cell configuration may comprise parameters of a serving cell (or multiple serving cells, such as a cell group), comprising one or more of the groups of parameters, such as an RRCReconfiguration message, an IE CellGroupConfigoran IE SpCellConfig (or the IE SCellConfig, in the case of an SCell). An LTM / CLTM or CHO candidate cell configuration may in one example comprise one or more of: i) the PCell configuration and one or more SCell configuration(s) of a Master Cell Group (MCG); i) the PSCell configuration and one or more SCell configuration(s) of a secondary Cell Group (SCG). The terms (LTM / CLTM or CHO) candidate configuration, LTM / CLTM or CHO configuration, (LTM / CLTM or CHO) candidate target cell configuration, (LTM / CLTM or CHO) target candidate (cell) configuration may be used interchangeably when referring to LTM or CHO candidate cell configuration. An LTM / CLTM candidate cell configuration may be associated with an identifier which is used in the signalingwhen referring to a certain LTM or CLTM candidate cell configuration, such as when the UE receives the LTM or CLTM candidate cell configuration and when the UE receives an LTM cell switch command indicating the UE to perform an LTM cell switch procedure to that LTM candidate cell. This identifier is sometimes known as the LTM / CLTM candidate cell configuration identity or LTM / CLTM candidate configuration index (or similar).

[0062] The text uses the term “cell” to identify a location (or coverage) on which the UE is located. However, the term “cell” can also be exchanged without any loss of meaning with the terms “radio resources”, “beams”, “TCI state”, or “Tracking reference signal (TRS)”. This is just to clarify that this invention does not target specifically a scenario where there is a cell, but rather when a UE uses a set of source radio resources and need to switch to a target set of radio resources. In such a case, radio resource can also identify a set of configurations, field, parameters, or ASN.1 structures or lEs.

[0063] The text further uses the term MCG to identify a first network entity that provides a first connectivity link to the UE and SCG to identify e second network entity that provides a second connectivity link to the UE. However, the terms “MCG” and “MN” can be exchanged without any loss of meaning as well as the terms “SCG” and “SN”. Moreover, the text uses the terms “first network node” and “second network node” to refer to a source cell / servingcell / source gNB-DU / S-DU and an LTM target cell / candidate gNB-DU / C-DU respectively.

[0064] As discussed above, according to the Rel-18 and Rel-19 versions of L1 / L2 triggered mobility (LTM), a UE performs L1-RSRP measurements on LTM candidate cells, which are “special cells” (SpCells), i.e., the primary cell PCell) in the MCG and the primary secondary cell (PSCell) in the SCG. The network performs LTM handover decisions, e.g., early UL and DL synchronization and cell switch, based on the reported L1 measurements. However, there is currently no support for performing L1-RSRP measurements on MCG and SCG SCells, i.e., on other cells in the same cell group as the LTM candidate cells.The configuration, activation, deactivation, or release of SCells depends upon radio conditions, e.g., signal strength or signal quality, as well as on user data requirements. Both of these factors vary overtime. The UE performs reporting on SCells based on Layer 3 (L3) measurements. Using L3 measurement and reporting, the UE can inform the network about the radio-related conditions of SCells, which may enable network to configure, activate, deactivate, or release SCells associated to the current SpCell. But, L3 measurement reporting is performed using RRC signaling, as opposed to the L1 measurement reports transmitted via PUCCH or PUSCH signaling in Rel-18, or event-triggered L1 measurement reports transmitted via MAC CE signaling. Therefore, the UE updating the network about radio-related measurements on SCells may take longer than the UE sending L1 measurement reports on the LTM candidate cells. Due to this, it may not be possible for the network to simultaneously execute the configuration, activation, deactivation, or release decisions for SCells, while performing the LTM cell switch to one of the LTM candidate cells.

[0065] The provision of measurement resource configuration related to the SCells is another problem with performing L1-measurements on the SCells in the same cell group as LTM candidate cells. The baseline measurement resource configuration for performing L1 measurements currently includes only information about reference signals (RS), e.g., SSB-RS or CSI-RS, in the LTM candidate cells that are the candidate target SpCells. Therefore, it is not possible for the UE to report L1-measurements on the SCells while sending L1-measurement report on an LTM candidate cell, because there is simply no information directly available to the UE about the beams or RSs in the SCells that are in the same cell group as the given LTM candidate cell. The only exception to this is when the SCell is specifically configured as another LTM candidate cell, which may not always be feasible.

[0066] A further aspect is that the current configuration of the resources on which the UE should measure does not indicate whether the resources are broadcasted by a SpCell or an SCell.Because of this, the UE must assume that such resources are for an SpCell and as a result, it is not possible for the network to execute the SCells configuration, activation, deactivation, or release decisions at the same time as performing the LTM cell switch on LTM candidate cells that are SpCells.

[0067] Figure 5 illustrates an example where a UE is initially configured with Cell A, Cell B, and Cell C, where Cell A is the SpCell, Cell B is an activated SCell, and Cell C is a deactivated SCell. It may be desirable to reconfigure the UE so that Cell B becomes the SpCell -this may be done with current LTM procedures by configuring Cell B as an LTM candidate cell and carrying out the LTM mobility procedures described above. It may also be desirable to configure Cell A and Cell C as SCells at the same time, and perhaps to also add Cell D, as a deactivated cell. This is not currently possible with LTM procedures -the configuration of the SCells other than the LTM candidate cell must be done based on slower, RRC-based procedures.

[0068] The techniques described herein address these problems. These techniques include methods implemented at the UE and the network to provide to the UE a measurement configuration in order to allow the UE to perform measurements on reference signals or beams of one or more Scells while the UE receives LTM candidate cell configuration. This may be done even for an SCell that is not configured as one of the LTM candidate cells.

[0069] According to some embodiments, a first network node (such as a source gNB or source DU) receives information from a second network node (such as an LTM candidate gNB or LTM candidate DU) about the measurement resource configuration, i.e., measurement resource set, associated to the Secondary cells (SCells) which are in the same cell group as the LTM candidate cell, during the LTM configuration phase. The first network node further configures the UE with the measurement resources in one or more SCell(s) that are in the same cell group as the LTM candidate cells, such that UE is able to perform L1-measurement and reporting onthe reference signals (RS), e.g., SSB-RS or CSI-RS, in SCells that are in the same cell group as a given LTM candidate cell.

[0070] Below, several inventive techniques for handling measurements of cells associated with LTM in a wireless network are described, with various examples. While the following describes these in the specific context of NR, the techniques can be more generally applicable, e.g., as NR evolves and / or as successor network technologies are defined.

[0071] First, techniques are described from the perspective of the UE. These include methods performed in a User Equipment (UE) that is configured by a first network node with at least one LTM candidate configuration that includes LTM CSI resource configuration which provides information about the beams, e.g., SSB index or CSI-RS index, that are transmitted by the candidate cell in the form of a resource set. An example method may comprise :

[0072] • Obtaining information about which LTM candidates that the UE should perform reference signal or beam measurements on.

[0073] • Performing L1-RSRP measurements on the indicated resource setforthe configured LTM candidate cell.

[0074] • Receiving an LTM cell switch command to one of the LTM Candidate cells.

[0075] In some embodiments, the UE obtains information about the measurement resource sets associated to the SCell(s) which are in the same cell group as each of the configured LTM candidate cell(s). This information can be referred to as “measurement information,” but may also be referred to as “measurement configuration information” or, more simply, as simply a “measurement configuration.” Measurement information or measurement configuration information can be provided to the UE in one, or several, messages.

[0076] In some embodiments or instances, the measurement information is obtained by the UE. The measurement information may indicate which reference signal or beam belongs to an SpCelland which belongs to one or more SCell(s). In one option, for example, a measurement configuration received by the UE includes a mappingwhere, for each included reference signal or beam, it is indicated whetherthis reference signal or beam is from an SpCell orfrom one or more SCell(s). In another option, the measurement configuration received by the UE includes two mappings, where a first mapping is for MCG and a second mapping is for SCG. In these embodiments or instances, the first mapping indicates, for each included reference signal or beam, whether this reference signal or beam is from the PCell or one or more SCell(s) of the MCG. Similarly, the second mapping indicates, for each included reference signal or beam, whether this reference signal or beam is from the PSCell or one or more SCell(s) of the SCG. In one variant, the UE can receive up to two mappings, a first mapping related to MCG and a second mapping related to SCG, and in case the UE receives only one mapping, it implicitly indicates that there is no SCell the UE is instructed to measure on for the Cell Group that is absent (eitherthe MCG orthe SCG).

[0077] In one option, the measurement configuration received by the UE includes one or more elements, where each element is a list of reference signals or beams. In this case, each element is indicated whether it is related to an SpCell or one or more SCells. In another option, the configuration received by the UE includes a list of elements, where each element in the list is a sequence comprising an identity, identifying a cell that can be used as an SCell for a given LTM candidate SpCell (e.g., a PCI, or a Cell ID, or an index indirectly referencing a cell that can be used as SCell with the PCell or as SCell with the PSCell), and reference signals or beams associated with that cell. In an option, the identified cell is not an LTM candidate cell, in another option, the cell is itself (another) LTM candidate cell (and it can be used as an SCell).

[0078] In some embodiments or instances, the UE may receive from the source cell a measurement configuration that explicitly identifies reference signals or beams for the SCell(s) associated with one or more configured LTM candidate cell(s). In one alternative, the SCell(s) are identifiedby the corresponding SCell index. In another alternative, the SCells are identified by their physical cell ID (PCI). In one option, SCell measurement resource configuration is provided outside the LTM candidate cell configuration.

[0079] In various embodiments or instances, the acquired measurement resource configuration forthe SCell measurements may be included in LTM-CSI-ResourceConfig lEs, with possibly new extensions. In one alternative, the measurement resource set configuration for SCell(s) measurements includes LTM candidate cell ID(s) for the LTM cell(s) that share(s) the same cell group as the given SCell. In another alternative, the measurement resource set configuration for SCells measurements includes some type of cell group ID, e.g., an UL SYNC ID, wherein the configured LTM candidate cell and the given SCell belong to the similar cell group and share the same cell group ID. In one alternative, the measurement resource set configuration for SCell(s) measurements includes a list of LTM candidate cell ID(s) which indicate on which configured LTM cell(s) one or more SCell(s) belong.

[0080] In some embodiments or instances, the acquired measurement resource configuration forthe SCell measurements in MCG may be included in another new IE outside the LTM-CSI-ResourceConfig lEs, e.g., LTM-CSI-SCell-ResourceConfig IE. In some alternative embodiments or instances, the acquired measurement resource configuration forthe SCell measurements for SCell in SCG may be included in another new IE outside the LTM-CSI-ResourceConfig lEs, e.g., LTM-CSI-SCG-ResourceConfig\E.

[0081] In some embodiments or instances, the UE receives, from a first network node, a measurement configuration that explicitly provides information about the measurement resources, i.e. , the RS(s) or beam(s) in the SCell(s) which are part of the same cell group(s) as one or more LTM candidate cell(s). In one option, the measurement resources or measurement RS(s) in the SCells are identified by their respective beam indices, e.g., SSB index or CSI-RS index. In another option, the measurement resources or measurement RS(s) in the SCells are identifiedby their respective physical layer resources indicators, e.g., SSB resource indicator (SSBRI) or CSI resource indicator (CRI).

[0082] In various embodiments or instances, the information about reference signal resources for measurement, e.g. reference signal resource set(s), of SCell(s) belonging to the same cell group as an LTM candidate cell may further include or be associated with, information related to the component carrier of each of the SCell(s). The information related to the component carrier of each of the SCell(s) may comprise, for example, any combination of one or more of:

[0083] DC location (where DC stands for Direct Current, used figuratively here, and where the DC location is located at the center of the bandwidth);

[0084] Offset to default DC location (e.g. in the form of the defaultDC-Locatoin-r17 V\e[d), Bandwidth,

[0085] - ARFCN;

[0086] Center frequency;

[0087] SSB frequency;

[0088] Low end frequency of the bandwidth;

[0089] High end frequency of the bandwidth;

[0090] Offset from the component carrier of the LTM candidate cell, i.e. offset from the primary component carrier, e.g. offset from the DC location, the center frequency, the frequency of the lower end of the bandwidth or the frequency of the higher end of the bandwidth of the primary component carrier; and / or

[0091] Cell index (e.g. in the form of a ServCelllndex field).

[0092] In addition, as a further option, the information related to the component carriers of the SCells in the cell group of an LTM candidate cell may comprise a CC-Group-r17 IE, or another IE (e.g., a new IE) with equivalent or similar content.In some embodiments or instances, the UE may receive, from a first network node, a measurement configuration that removes a previously provided configuration of measurement resources, i.e., the RS(s) or beam(s) forSCell(s). In one option, only the configuration about measurement resources of SCell(s) associated with specific LTM candidate cell(s) is(are) removed.

[0093] In some embodiments or instances, the UE may receive from a first network node, a measurement configuration that explicitly provides constraints on the SCells the UE can measure / report on. Such constraints can be one or more of: a maximum number of SCells, a maximum number of SCells per SpCell, a maximum number of SCells for SCG, a maximum number of SCells for MCG, a restriction to only consider SCells for MCG (or to not consider SCells for SCG), a restriction to only consider SCells for SCG (or to not consider SCells for MCG), or an indication that SCells for PCell and PSCells can be measured.

[0094] In some of these embodiments or instances, the UE may have one or more of several options for how to comply with these constraints while still making the measurements as useful as possible. These options, which may be specified or indicated in the measurement information received from the network, in some embodiments or instances, may comprise one or more of any of the following, for example:

[0095] The UE may first measure on at least one SCell in every cell group (MCG or SCG) that is included in the measurement configuration, and then, if the maximum number of SCells is not reached yet, the UE may continue to measure one more SCell per configured cell group.

[0096] The UE may first measure on at least one SCell in every cell group (MCG or SCG) that is included in the measurement configuration, and then, if the maximum number of SCells is not reached yet, the UE may prioritize measuring on SCells in MCGs to SCells in SCGs.The UE may first prioritize measuring on SCells in MCGs, and if the total number of such SCells in the measurement configuration is smallerthan the maximum number of SCells in the constraint, the UE may also measure on SCells in SCGs.

[0097] The UE may prioritize measuring all SCells in each cell group until the maximum number of SCells in the constraint is reached or the remaining number of SCell(s) until the maximum number of SCells in the constraint is less than the number of SCell(s) in a further cell group (in which case the UE measures that number of SCell(s) in the further cell group).

[0098] The UE may order the SCell measurement results in order of measured signal strength (e.g. RSRP) or signal quality (e.g. RSRQ) (or other quantity indicative of the channel quality such as SNR, SINR or RSSI) with the highest or best first and the lowest or worst last and choose to report the N highest / best measurement results where N is equal to the maximum number of SCells in the constraint.

[0099] The above options for the UE’s behavior may, in some embodiments, be performed according to the UE’s autonomous choice (e.g., based on UE implementation). In other embodiments, this UE behavior may explicitly or implicitly be indicated in the measurement configuration, e.g., together with the constraints on the number of SCells.

[0100] The inventive techniques described herein may also be described from the perspective of the “first network node” mentioned in the various example embodiments and instances described above, where the “first network node” is typically the node operating the source cell for an LTM procedure. Embodiments of the presently disclosed techniques, apparatuses, and systems thus include methods performed by a first network node that configures the UE with at least one LTM candidate configuration, which in turn includes, references, or is otherwise associated with a measurement configuration (e.g., an LTM CSI resource configuration) that provides information about the reference signals or beams, e.g., SSB index or CSI-RS index, transmittedby an LTM candidate cell in the form of a resource set. Various example methods may include one, several, or all of these steps:

[0101] • Requesting information from a second network node, e.g., one or more LTM target cells, about which reference signals or beams the UE shall measure.

[0102] • Receiving information from a second network node, e.g., one or more LTM target cells, about which reference signals or beams the UE shall measure.

[0103] • Providing the UE with indications of which reference signals or beams the UE shall measure on a second or third network nodes, including the information on LTM target cell beams that UE should measure on.

[0104] In some embodiments, the first network node requests information from the second network node(s) (the LTM target cells) about the measurement resources, i.e. , beams or reference signals, associated to the SCell(s) of the second network node, e.g.e, via an existing or new class 1 message such as the UE CONTEXT MODIFICATION REQUEST or UE CONTEXT MODIFICATION RESPONSE Message. This request may be sent directly, or via gNB-CU, in various embodiments.

[0105] In some embodiments, the requested information from the second network node about the measurement resources includes one or multiple of the following:

[0106] • SCell identifier, e.g., SCell index or the SCell physical cell ID (PCI).

[0107] • In another alternative, the requested information is about the cell group ID, e.g., an UL SYNC. ID, such that the configured LTM target cell and the SCell belong to a similar cell group and have an identical cell group ID.

[0108] • Reference signal or beam identifier, e.g., SSB index or CSI-RS index, or the related measurement resource indicator, e.g., SSBRI or CRI.

[0109] • A mapping between a reference signal or beam and whether this belongs to an SCell or SpCell. Forexample, the mapping could be in the form of [Beam=1, SCell_ID=10].In various embodiments or instances, the first network node may receive some or all of the requested information about the measurement resources, i.e. , beams or reference signals, associated to the SCell(s) of the second network node, via an existing or new message or a class 1 procedure, e.g., UE CONTEXT MODIFICATION REQUEST or UE CONTEXT MODIFICATION RESPONSE Message, eitherdirectlyorvia gNB-CU. Alternatively, the first network node may receive some or all of the requested information via an existing or new message of a class 2 procedure, eitherdirectlyorvia gNB-CU.

[0110] In some embodiments or instances, at least one of the network nodes is a gNB with a split architecture, such that it is divided into a CU and one or more DU(s). In some of these embodiments or instances, the CU in a first network node that has such a split architecture may forward at least part of the received SCell-related information to the DU to which the UE subject to a potential LTM cell switch is connected. Furthermore, if the second network node has a split architecture, then the CU of the second network node may retrieve at least part of the SCell related information from a potential candidate DU (i.e., a DU controlling a potential LTM candidate cell) before sending the SCell-related information to the first network node (e.g., to the CU of the first network node). This CU-DU communication may take the form of F1AP message exchange(s) or another new type of message.

[0111] In some embodiments or instances, where the first and the second network nodes are two gNBs or two CUs, i.e., a source gNB or CU and a candidate or target gNB or CU, the SCell related information may be transferred between the first and second network nodes using an existing or newXnAP message of a class 1 procedure, e.g., HANDOVER REQUEST ACKNOWLEDGE or LTM CONFIGURATION UPDATE, or LTM CONFIGURATION UPDATE ACKNOWLEDGE.

[0112] Error! Reference source not found. In some embodiments or instances, the first network node configures the UE with measurement resource configuration or measurement resource setassociated to SCells that belong to the second network node, such that the measurement resource configuration includes one or multiple of the following:

[0113] • SCell identifier, e.g., SCell index or the SCell physical cell ID (PCI).

[0114] • LTM candidate cell ID(s) for the second network node (LTM target cell) which share(s) the similar cell group as the given SCell.

[0115] • Cell group ID, e.g., an UL SYNC. ID, such the second network node and the SCell belong to the similar cell group and have an identical cell group ID.

[0116] • Reference signal or beam identifier, e.g., SSB index or CSI-RS index, or the related measurement resource indicator, e.g., SSBRI or CRI.

[0117] • A mapping between a reference signal or beam and whether this belongs to an SCell or SpCell. Forexample, the mapping could be in the form of [Beam=1, SCell_ID=10].

[0118] In some embodiments or instances, the SCell measurement resource configuration provided by the first network node is outside the LTM candidate cell configuration but within the LTM-CSI-ResourceConfig lEs, e.g., LTM-CSI-SCell-ResourceConfig IE. In others, the SCell measurement resource set configuration provided by the first network node may be contained in another new IE outside the LTM-CSI-ResourceConfig lEs.

[0119] In some embodiments or instances, the configuration sent to the UE further comprises information related to the component carriers of the SCell(s), e.g., the type of component carrier related information described above in the embodiments from the UE perspective.

[0120] In some embodiments or instances, the first network node is a serving DU or serving CU (or source cell) and the second network node is a serving DU, a candidate DU, or a candidate CU.

[0121] In some embodiments or instances, the first network node sends to the UE a measurement configuration that explicitly provides constraints on the SCells the UE can measure / report on. Such constraints can be one or more of, for example: a maximum number of SCells, a maximumnumber of SCells per SpCell, a maximum number of SCells for an SCG, a maximum number of SCells for an MCG, a restriction to only consider SCells for MCG (or to not consider SCells for SCG), a restriction to only consider SCells for SCG (or to not consider SCells for MCG), an indication that SCells for PCell and PSCells can be measured.

[0122] The measurement configuration may further include instructions to the UE on howto comply with the constraints on the number of SCells. These instructions may comprise e.g.:

[0123] The UE may first ensure to measure on at least one SCell in every cell group (MCG or SCG) that is included in the measurement configuration, and then, if the maximum number of SCells is not reached yet, the UE may continue to measure one more SCell per configured cell group.

[0124] The UE may first ensure to measure on at least one SCell in every cell group (MCG or SCG) that is included in the measurement configuration, and then, if the maximum number of SCells is not reached yet, the UE may prioritize measuring on SCells in MCGs to SCells in SCGs.

[0125] The UE may first prioritize measuring on SCells in MCGs, and if the total number of such SCells in the measurement configuration is smallerthan the maximum number of SCells in the constraint, the UE may also measure on SCells in SCGs.

[0126] The UE may prioritize to measure all SCells in each cell group until the maximum number of SCells in the constraint is reached or the remaining number of SCell(s) until the maximum number of SCells in the constraint is less than the number of SCell(s) in a further cell group (in which case the UE measures that number of SCell(s) in the further cell group).

[0127] The UE may order the SCell measurement results in order of measured signal strength (e.g., RSRP) or signal quality (e.g. RSRQ) (or other quantity indicative of the channel quality such as SNR, SINR or RSSI) with the highest or best first and the lowest or worstlast and choose to report the N highest / best measurement results where N is equal to the maximum number of SCells in the constraint.

[0128] In some embodiments or instances, the first network node receives, from a second network node ora third network node, constraints on the SCells of the second network node or third network node the UE may measure / report on. Such constraints can be one or more of: a maximum number of SCells, a maximum number of SCells per SpCell, a maximum number of SCells for an SCG, a maximum number of SCells for an MCG, a restriction to only consider SCells for MCG (or to not consider SCells for SCG), a restriction to only consider SCells for SCG (or to not consider SCells for MCG), an indication that SCells for PCell and PSCells can be measured.

[0129] Associated with these received constraints there may further be instructions governing how the UE should comply with the constraints. These instructions may comprise e.g.:

[0130] The UE may first ensure to measure on at least one SCell in every cell group (MCG or SCG) that is included in the measurement configuration, and then, if the maximum number of SCells is not reached yet, the UE may continue to measure one more SCell per configured cell group.

[0131] The UE may first ensure to measure on at least one SCell in every cell group (MCG or SCG) that is included in the measurement configuration, and then, if the maximum number of SCells is not reached yet, the UE may prioritize measuring on SCells in MCGs to SCells in SCGs.

[0132] The UE may first prioritize measuring on SCells in MCGs, and if the total number of such SCells in the measurement configuration is smallerthan the maximum number of SCells in the constraint, the UE may also measure on SCells in SCGs.

[0133] The UE may prioritize to measure all SCells in each cell group until the maximum number of SCells in the constraint is reached or the remaining number of SCell(s) untilthe maximum number of SCells in the constraint is less than the number of SCell(s) in a further cell group (in which case the UE measures that number of SCell(s) in the further cell group).

[0134] The UE may order the SCell measurement results in order of measured signal strength (e.g., RSRP) or signal quality (e.g., RSRQ) (or other quantity indicative of the channel quality such as SNR, SINR or RSSI) with the highest or the best first and the lowest or the worst last.

[0135] In some embodiments or instances, the first network node (e.g., the source DU) refrains from configuring L1 measurements on SCells if the first network node receives, from the second network node (e.g., the source CU), an implicit or an explicit indication that L3 measurements are used for SpCell(s) (or an implicit or explicit indication that L1 measurements are not used forSpCell(s)).

[0136] The inventive techniques described herein may also be described from the perspective of the “second network node” mentioned in the various example embodiments and instances described above, where the “second network node” is typically the node operating the target cell for an LTM procedure. Embodiments of the presently disclosed techniques, apparatuses, and systems thus include methods performed by a second network node, which is the LTM target cell for the UE comprising the provision of LTM CSI resource configuration to the first network node, with some methods comprising the step of receiving, from the first network node, a request to provide information about measurement resources, i.e. , beams or reference signals, associated to the SCell(s) of the second network node which the UE should measure, via an existing or new 1 message of a class 1 procedure, e.g., UE CONTEXT MODIFICATION REQUEST or UE CONTEXT MODIFICATION RESPONSE Message, either directly or via gNB-CU.

[0137] In various embodiments or instances, the second network node or the third network node provides the requested information to the first network node about the measurementresources, i.e., beams or reference signals, associated to the SCell(s) of the second network node. This may be done, for example, using an existing or new message of a class 1 procedure, e.g., UE CONTEXT MODIFICATION REQUEST or UE CONTEXT MODIFICATION RESPONSE message, either directly or via gNB-CU. Alternatively, it may be done using an existing or new message of a class 2 procedure, either directly or via gNB-CU. As another alternative, an existing or newXnAP message of a class 1 procedure, such as a HANDOVER REQUEST ACKNOWLEDGE or LTM CONFIGURATION UPDATE, or LTM CONFIGURATION UPDATE ACKNOWLEDGE message, may be used.

[0138] In some embodiments or instances, the information shared by the second network node or the third network node with the first network node about the measurement resources includes / comprises one or multiple of the following:

[0139] • SCell identifier, e.g., SCell index or the SCell physical cell ID (PCI).

[0140] • Cell group ID, e.g., an UL SYNC. ID, such that the second network node and the SCell belong to the similar cell group and have an identical cell group ID.

[0141] • Reference signal or beam identifier, e.g., SSB index or CSI-RS index, or the related measurement resource indicator, e.g., SSBRI or CRI

[0142] • A mapping between a reference signal or beam and whether this belongs to an SCell or PScell. For example, the mapping could be in the form of [Beam=1, SCellJ D=10] .

[0143] In various embodiments or instances, the first network node is a serving DU or serving CU (or source cell) and the second network node and / or the third network node is a serving DU, a candidate DU, or a candidate CU.

[0144] In some embodiments or instances, the second network node may send, to the first network node, constraints on the SCells of the second network node or the third network node the UE can measure / report on. Such constraints can be one or more of: a maximum number of SCells, a maximum number of SCells per SpCell, a maximum number of SCells for an SCG, a maximumnumber of SCells for an MCG, a restriction to only consider SCells for MCG (or to not consider SCells for SCG), a restriction to only consider SCells for SCG (or to not consider SCells for MCG), an indication that SCells for PCell and PSCells can be measured.

[0145] Associated with these constraints there may further be instructions governing how the UE should comply with the constraints. These instructions may comprise anyone or more of the following, for example:

[0146] The UE may first ensure to measure on at least one SCell in every cell group (MCG or SCG) that is included in the measurement configuration, and then, if the maximum number of SCells is not reached yet, the UE may continue to measure one more SCell per configured cell group.

[0147] The UE may first ensure to measure on at least one SCell in every cell group (MCG or SCG) that is included in the measurement configuration, and then, if the maximum number of SCells is not reached yet, the UE may prioritize measuring on SCells in MCGs to SCells in SCGs.

[0148] The UE may first prioritize measuring on SCells in MCGs, and if the total number of such SCells in the measurement configuration is smallerthan the maximum number of SCells in the constraint, the UE may also measure on SCells in SCGs.

[0149] The UE may prioritize to measure all SCells in each cell group until the maximum number of SCells in the constraint is reached or the remaining number of SCell(s) until the maximum number of SCells in the constraint is less than the number of SCell(s) in a further cell group (in which case the UE measures that number of SCell(s) in the further cell group).

[0150] The UE may order the SCell measurement results in order of measured signal strength (e.g., RSRP) or signal quality (e.g., RSRQ) (or other quantity indicative of the channel quality such as SNR, SINR or RSSI) with the highest or best first and the lowest or worst last.In some embodiments or instances, the second network node (e.g., the source CU) orthe third network node (e.g., a candidate CU) sends to the first network node (e.g., the source DU) an explicit or implicit indication that L3 measurements are used for SpCell(s) (or an implicit or explicit indication that L1 measurements are not used for SpCell(s)).

[0151] The various techniques described above for providing the UE with measurement resource configuration for one or more SCells that are in the same cell group as a LTM candidate cell for the UE may provide several advantages, including that:

[0152] • The UE may perform L1 -measurement and reporting on the SCells in a similar way as the LTM candidate cells that are the SpCells, which means that the network is able to receive from the UE a common report containing radio-related measurements on SpCells and SCells, thereby with no delay in the reporting of the radio-related measurements forthe two type of cells. The UE may perform L1-measurement and reporting on the SCells, even if those SCells are not configured as LTM candidate cells.

[0153] • The UE may perform L1-measurement and reporting on the SCells, even if those SCells are deactivated or not a part of the UE configuration. If the UE has received the related measurement resource configuration forthat SCell, the UE may always perform and report radio-related measurements for the SCell.

[0154] • The network may take informed decisions about the SCell activation or deactivation upon LTM cell switch, therefore reducing any interruptions in providing the aggregated throughput of the primary and the secondary cells.

[0155] • The network may take informed decisions about the SCell addition and release before the LTM cell switch, therefore ensuring that the UE is served by a better quality SCell upon LTM cell switch.

[0156] In view of the explanation and several detailed examples provided above, it will be appreciated that Figures 6, 7, and 8 are process flow diagrams illustrating example methods such as mightbe carried out by a UE (which term is used here to generally refer to an access device for a wireless communication system), first network node, and second network node, respectively. Each of these illustrated methods is intended to encompass many, if not all, of the example methods and techniques described above. Accordingly, where the terminology or semantics used to describe Figures 6, 7, and 8 differ slightlyfrom correspondingterms used to describe the various examples above, the former should be understood to be synonymous with or to be generalizations of the latter, unless the context for either clearly indicates otherwise.

[0157] First, Figure 6 illustrates a method, in / performed by a UE, for handling measurements of cells associated with Layer-1 / Layer-2-triggered mobility, LTM, in a wireless network. As shown at block 610, the illustrated method comprises receiving, from a network node in the wireless network, measurement information specifying one or more measurement resources for one or more secondary cells, SCells. The one or more SCells are in a same group as an LTM candidate cell configured for the UE but the one or more Scells are not configured as LTM candidate cells for the UE. (The measurement information may also include measurement resources for an SCell that is configured as an LTM candidate cell.) The method further comprises, as shown at block 620, performing Layer-1 measurements on at least one of the measurement resources for at least one of the one or more SCells.

[0158] In some embodiments or instances, the method may further comprising reporting one or more of the Layer-1 measurements to the wireless network, using only lower layer signaling, as shown at block 630. This block is illustrated with a dashed outline so as to indicate that it is an “optional” step, in that it is not the case that every instance of providing a UE with the measurement information ultimately results in the UE reporting any measurements. In some further instances or embodiments, the method may further comprise receiving, from the wireless network, a lower layer indication to activate, deactivate, or release at least one of the one or more SCells, in response to said reporting. This is shown at block 640, which is alsoillustrated as “optional,” since, again, not every instance of measuring and reporting Layer-1 measurements leads to a change in configuration. The method may still further comprise activating, deactivating, or releasing the at least one of the one or more SCells, in response to the indication, as shown at block 650.

[0159] The performing of Layer-1 measurements shown at block 610 may comprise performing Layer-1 Received Signal Reference Power, L1-RSRP, measurements, in at least some embodiments or instances. In some embodiments or instances, the measurement information comprises a measurement resource set for at least one of the one or more SCells. The measurement information may identify two or more reference signals and / or beams, for example, and include an indication of which reference signal and / or beam belongs to which SCell or which Special Cell, SPCell, in the same group as the LTM candidate cell configured for the UE.

[0160] In some embodiments or instances, the measurement information comprises a measurement configuration that explicitly identifies one or more reference signals and / or beams and explicitly associates the identified one or more reference signals and / or beams with an SCell in the same group as the LTM candidate cell configured for the UE. In some embodiments or instances, the measurement information identifies at least one of the one or more SCells with an SCell index or a physical cell identifier, PCI. In some embodiments or instances, the measurement information may identify at least one measurement resource using a Synchronization Signal Block, SSB, index and / or a Channel State Information Reference Signal, CSI-RS, index.

[0161] In some embodiments or instances, the measurement information comprises information indicating one or more constraints regarding which SCells to be measured and / or how many SCells to be measured. Details of example constraints and how they might be communicated to and handled by the UE were given above.The method shown in Figure 6, as noted above, is a generalization of the various UE-based techniques described above. Thus, the several variations and alternatives described above in connection with those techniques are equally applicable to the method of Figure 6.

[0162] Figure 7 illustrates an example method, in / performed by a first network node, for handling measurements of cells associated with Layer-1 / Layer-2-triggered mobility, LTM, in a wireless network. It will be appreciated that this method and its variants complement the example method shown in Figure 6.

[0163] The illustrated method includes, as shown at block 730, the step of sending, to a UE, measurement information specifying one or more measurement resources for one or more secondary cells, SCells. The one or more Scells are in a same group as an LTM candidate cell configured for the UE , and the one or more SCells are not configured as LTM candidate cells for the UE. In some embodiments or instances the method includes, as shown at block 710 and 720, the steps of requesting measurement information from a second network node that provides the LTM candidate cell configured for the UE and receiving the measurement information to be sent to the UE from the second network node, in response.

[0164] As shown at block 740, the method may further comprise, in some instances, receiving, from the UE, one or more Layer-1 measurements relating to at least one of the one or more SCells, via lower layer signaling. The method may still further comprise determining to activate, deactivate, or release at least one of the one or more SCells, based on the Layer-1 measurements. This is shown at block 750. The activating, deactivating, or releasing may be carried out by sending lower layer signaling to the UE, in some embodiments or instances.

[0165] In some embodiments or instances, the measurement information sentto the UE comprises a measurement resource set for at least one of the one or more SCells. The measurement information sentto the UE may identify two or more reference signals and / or beams, forexample, and may include an indication of which reference signal and / or beam belongs to which SCell or which Special Cell, SPCell, in the same group as the LTM candidate cell configured for the UE.

[0166] In some embodiments or instances, the measurement information sentto the UE comprises a measurement configuration that explicitly identifies one or more reference signals and / or beams and explicitly associates the identified one or more reference signals and / or beams with an SCell in the same group as the LTM candidate cell configured for the UE. The measurement information sent to the UE may identify at least one of the one or more SCells with an SCell index or a physical cell identifier, PCI, for example. In some embodiments or instances, the measurement information sentto the UE may at least one measurement resource using a Synchronization Signal Block, SSB, index and / or a Channel State Information Reference Signal, CSI-RS, index.

[0167] In some embodiments or instances, the measurement information sent to the UE comprises information indicating one or more constraints regarding which SCells to be measured and / or how many SCells to be measured. Examples of these constraints and how the UE may respond under these constraints were detailed above. Each of those variants, as well as other variants relating to the operation of the first network node detailed above, are applicable to some embodiments or instances of the method illustrated in Figure 7.

[0168] Figure 8 illustrates an example method, in a second network node, for handling measurements of cells associated with Layer-1 / Layer-2-triggered mobility, LTM, in a wireless network. It will be appreciated that this method and its variants complement the example methods shown in Figure 6 and Figure 7.

[0169] As shown at block 810, the illustrated method comprises the step of receiving, from a first network node, a request for measurement information specifying one or more measurementresources for one or more secondary cells, SCells. The one or more Scells are in a same group as an LTM candidate cell configured for a user equipment, UE. The measurement information is to be provided by the second network node. The one or more Scells are not configured as LTM candidate cells for the UE. The method further comprises, as shown at block 820, the step of sending, to the first network node, measurement information specifying at least one measurement resource for at least one SCell.

[0170] In some embodiments or instances, the measurement information sentto the UE comprises a measurement resource set for at least one of the one or more SCells. The measurement information sentto the UE may identify two or more reference signals and / or beams, for example, and may include an indication of which reference signal and / or beam belongs to which SCell or which Special Cell, SPCell, in the same group as the LTM candidate cell configured for the UE.

[0171] In some embodiments or instances, the measurement information sent to the first network node comprises a measurement configuration that explicitly identifies one or more reference signals and / or beams and explicitly associates the identified one or more reference signals and / or beams with an SCell in the same group as the LTM candidate cell configured for the UE. The measurement information sentto the first network node may identify at least one of the one or more SCells with an SCell index or a physical cell identifier, PCI, for example. In some embodiments or instances, the measurement information sent to the UE may at least one measurement resource using a Synchronization Signal Block, SSB, index and / or a Channel State Information Reference Signal, CSI-RS, index.

[0172] In some embodiments or instances, the measurement information sent to the first network node comprises information indicating one or more constraints regarding which SCells to be measured and / or how many SCells to be measured. Examples of these constraints and how the UE may respond under these constraints were detailed above. Each of those variants, as well asother variants relating to the operation of the second network node detailed above, are applicable to some embodiments or instances of the method illustrated in Figure 8.

[0173] Figure 9 shows an example of a communication system 900 in accordance with some embodiments. In this example, communication system 900 includes telecommunication network 902 that includes access network 904 (e.g., RAN) and a core network 906, which includes one or more core network nodes 908. Access network 904 includes one or more access network nodes, such as network nodes 91 Oa-b (one or more of which may be generally referred to as network nodes 910), or any other similar 3GPP access node or non-3GPP access point. Network nodes 910 facilitate direct or indirect connection of UEs, such as by connecting UEs 912a-d (one or more of which may be generally referred to as UEs 912) to core network 906 over one or more wireless connections.

[0174] Example wireless communications over a wireless connection include transmitting and / or receiving wireless signals using electromagnetic waves, radio waves, infrared waves, and / or other types of signals suitable for conveying information without the use of wires, cables, or other material conductors. Moreover, in different embodiments, communication system 900 may include any number of wired or wireless networks, network nodes, UEs, and / or any other components or systems that may facilitate or participate in the communication of data and / or signals whether via wired or wireless connections. Communication system 900 may include and / or interface with any type of communication, telecommunication, data, cellular, radio network, and / or other similar type of system.

[0175] UEs 912 may be any of a wide variety of communication devices, including wireless devices arranged, configured, and / or operable to communicate wirelessly with network nodes 910 and other communication devices. Similarly, network nodes 910 are arranged, capable, configured, and / or operable to communicate directly or indirectly with UEs 912 and / or with other network nodes or equipment in telecommunication network 902 to enable and / or provide networkaccess, such as wireless network access, and / or to perform other functions, such as administration in telecommunication network 902.

[0176] In the depicted example, core network 906 connects network nodes 910 to one or more hosts, such as host 916. These connections may be direct or indirect via one or more intermediary networks or devices. In other examples, network nodes may be directly coupled to hosts. Core network 906 includes one or more core network nodes (e.g., 908) that are structured with hardware and software components. Features of these components may be substantially similar to those described with respect to the UEs, network nodes, and / or hosts, such that the descriptions thereof are generally applicable to the corresponding components of core network node 908. Example core network nodes include functions of one or more of a Mobile Switching Center (MSC), Mobility Management Entity (MME), Home Subscriber Server (HSS), Access and Mobility Management Function (AMF), Session Management Function (SMF), Authentication Server Function (AUSF), Subscription Identifier De-concealing function (SIDF), Unified Data Management (UDM), Security Edge Protection Proxy (SEPP), Network Exposure Function (NEF), and / or a User Plane Function (UPF).

[0177] Host 916 may be under the ownership or control of a service provider other than an operator or provider of access network 904 and / or telecommunication network 902, and may be operated by the service provider or on behalf of the service provider. Host 916 may host a variety of applications to provide one or more service. Examples of such applications include live and prerecorded audio / video content, data collection services such as retrieving and compiling data on various ambient conditions detected by a plurality of UEs, analytics functionality, social media, functions for controlling or otherwise interacting with remote devices, functions for an alarm and surveillance center, or any other such function performed by a server.

[0178] As a whole, communication system 900 of Figure 9 enables connectivity between the UEs, network nodes, and hosts. In that sense, the communication system may be configured tooperate according to predefined rules or procedures, such as specific standards that include, but are not limited to: Global System for Mobile Communications (GSM); Universal Mobile Telecommunications System (UMTS); LongTerm Evolution (LTE), and / or other suitable 2G, 3G, 4G, 5G standards, or any applicable future generation standard (e.g., 6G); wireless local area network (WLAN) standards, such as the Institute of Electrical and Electronics Engineers (IEEE) 1002.11 standards (WiFi); and / or any other appropriate wireless communication standard, such as the Worldwide Interoperability for Microwave Access (WiMax), Bluetooth, Z-Wave, Near Field Communication (NFC) ZigBee, LiFi, and / or any low-power wide-area network (LPWAN) standards such as LoRa and Sigfox.

[0179] In some examples, telecommunication network 902 is a cellular network that implements 3GPP standardized features. Accordingly, telecommunication network 902 may support network slicing to provide different logical networks to different devices that are connected to telecommunication network 902. For example, telecommunication network 902 may provide Ultra Reliable Low Latency Communication (URLLC) services to some UEs, while providing Enhanced Mobile Broadband (eMBB) services to other UEs, and / or Massive Machine Type Communication (mMTC) / Massive loT services to yet further UEs.

[0180] In some examples, UEs 912 are configured to transmit and / or receive information without direct human interaction. For instance, a UE may be designed to transmit information to access network 904 on a predetermined schedule, when triggered by an internal or external event, or in response to requests from access network 904. Additionally, a UE may be configured for operating in single- or multi-RAT or multi-standard mode. For example, a UE may operate with anyone orcombination of Wi-Fi, NR (New Radio) and LTE, i.e., being configured for multi-radio dual connectivity (MR-DC), such as E-UTRAN (Evolved-UMTS Terrestrial Radio Access Network) New Radio - Dual Connectivity (EN-DC).In the example, hub 914 communicates with access network 904 to facilitate indirect communication between one or more UEs (e.g., UE 912c and / or 912d) and network nodes (e.g., network node 910b). In some examples, hub 914 may be a controller, router, content source and analytics, or any of the other communication devices described herein regarding UEs. For example, hub 914 may be a broadband router enabling access to core network 906 for the UEs. As another example, hub 914 may be a controller that sends commands or instructions to one or more actuators in the UEs. Commands or instructions may be received from the UEs, network nodes 910, or by executable code, script, process, or other instructions in hub 914. As another example, hub 914 may be a data collector that acts as temporary storage for UE data and, in some embodiments, may perform analysis or other processing of the data. As another example, hub 914 may be a content source. For example, for a UE that is a VR headset, display, loudspeaker or other media delivery device, hub 914 may retrieve VR assets, video, audio, or other media or data related to sensory information via a network node, which hub 914 then provides to the UE either directly, after performing local processing, and / or after adding additional local content. In still another example, hub 914 acts as a proxy server or orchestrator for the UEs, in particular in if one or more of the UEs are low energy loT devices.

[0181] Hub 914 may have a constant / persistent or intermittent connection to network node 910b. Hub 914 may also allow for a different communication scheme and / or schedule between hub 914 and UEs (e.g., UE 912c and / or 912d), and between hub 914 and core network 906. In other examples, hub 914 is connected to core network 906 and / or one or more UEs via a wired connection. Moreover, hub 914 may be configured to connect to an M2M service provider over access network 904 and / or to another UE over a direct connection. In some scenarios, UEs may establish a wireless connection with network nodes 910 while still connected via hub 914 via a wired orwireless connection. In some embodiments, hub 914 may be a dedicated hub-that is, a hub whose primary function is to route communications to / from the UEs from / to network node 910b. In other embodiments, hub 914 may be a non-dedicated hub-that is, a devicewhich is capable of operating to route communications between the UEs and network node 910b, but which is additionally capable of operating as a communication start and / or end point for certain data channels.

[0182] Figure 10 shows a UE 1000 in accordance with some embodiments. Examples of a UE include, but are not limited to, a smart phone, mobile phone, cell phone, voice over IP (VoIP) phone, wireless local loop phone, desktop computer, personal digital assistant (PDA), wireless cameras, gaming console or device, music storage device, playback appliance, wearable terminal device, wireless endpoint, mobile station, tablet, laptop, laptop-embedded equipment (LEE), laptop-mounted equipment (LME), smart device, wireless customer-premise equipment (CPE), vehicle-mounted or vehicle embedded / integrated wireless device, etc. Other examples include any UE identified by 3GPP, including a narrow band internet of things (NB-loT) UE, a machine type communication (MTC) UE, and / or an enhanced MTC (eMTC) UE.

[0183] A UE may support device-to-device (D2D) communication, for example by implementing a 3GPP standard for sidelink communication, Dedicated Short-Range Communication (DSRC), vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I), or vehicle-to-everything (V2X). In other examples, a UE may not necessarily have a user in the sense of a human user who owns and / or operates the relevant device. Instead, a UE may represent a device that is intended for sale to, or operation by, a human user but which may not, orwhich may not initially, be associated with a specific human user (e.g., a smart sprinkler controller). Alternatively, a UE may represent a device that is not intended for sale to, or operation by, an end user but which may be associated with or operated for the benefit of a user (e.g., a smart power meter).

[0184] UE 1000 includes processing circuitry 1002 that is operatively coupled via bus 1004 to input / output interface 1006, power source 1008, memory 1010, communication interface 1012, and possibly other components not explicitly shown. Certain UEs may utilize all or a subset of the components shown in Figure 10. The level of integration between the components may varyfrom one UE to another UE. Further, certain UEs may contain multiple instances of a component, such as multiple processors, memories, transceivers, transmitters, receivers, etc.

[0185] Processing circuitry 1002 is configured to process instructions and data and may be configured to implement any sequential state machine operative to execute instructions stored as machine-readable computer programs in memory 1010. Processing circuitry 1002 may be implemented as one or more hardware-implemented state machines (e.g., in discrete logic, field-programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), etc.); programmable logic together with appropriate firmware; one or more stored computer programs, general-purpose processors, such as a microprocessor or digital signal processor (DSP), together with appropriate software; or any combination of the above. For example, processing circuitry 1002 may include multiple central processing units (CPUs). The processing circuitry 1002 may be operable to provide, either alone or in conjunction with other UE 1000 components, such as the memory 1010, UE 1000 functionality. For example, the processing circuitry 1002 may be configured to cause the UE 1000 to perform the methods as described herein, such as described with reference to Figure 6.

[0186] In the example, input / output interface 1006 may be configured to provide an interface or interfaces to an input device, output device, or one or more input and / or output devices.

[0187] Examples of an output device include a speaker, a sound card, a video card, a display, a monitor, a printer, an actuator, an emitter, a smartcard, another output device, or any combination thereof. An input device may allow a user to capture information into UE 1000. Examples of an input device include a touch-sensitive or presence-sensitive display, a camera (e.g., a digital camera, a digital video camera, a web camera, etc.), a microphone, a sensor, a mouse, a trackball, a directional pad, a trackpad, a scroll wheel, a smartcard, and the like. The presence-sensitive display may include a capacitive or resistive touch sensor to sense input from a user. A sensor may be, for instance, an accelerometer, a gyroscope, a tilt sensor, a forcesensor, a magnetometer, an optical sensor, a proximity sensor, a biometric sensor, etc., or any combination thereof. An output device may use the same type of interface port as an input device. For example, a Universal Serial Bus (USB) port may be used to provide an input device and an output device.

[0188] In some embodiments, power source 1008 is structured as a battery or battery pack. Other types of power sources, such as an external power source (e.g., an electricity outlet), photovoltaic device, or power cell, may be used. Power source 1008 may further include power circuitry for delivering power from power source 1008 itself, and / or an external power source, to the various parts of UE 1000 via input circuitry or an interface such as an electrical power cable. Delivering power may be, for example, for charging power source 1008. Power circuitry may perform any formatting, converting, or other modification to the power from power source 1008 to make the power suitable for the respective components of UE 1000 to which power is supplied.

[0189] Memory 1010 may be or be configured to include memory such as random access memory (RAM), read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), magnetic disks, optical disks, hard disks, removable cartridges, flash drives, and so forth. In one example, memory 1010 includes one or more application programs 1014, such as an operating system, web browser application, a widget, gadget engine, or other application, and corresponding data 1016. Memory 1010 may store, for use by UE 1000, any of a variety of various operating systems or combinations of operating systems.

[0190] Memory 1010 may be configured to include a number of physical drive units, such as redundant array of independent disks (RAID), flash memory, USB flash drive, external hard disk drive, thumb drive, pen drive, key drive, high-density digital versatile disc (HD-DVD) optical disc drive, internal hard disk drive, Blu-Ray optical disc drive, holographic digital data storage (HDDS)optical disc drive, external mini-dual in-line memory module (DIMM), synchronous dynamic random access memory (SDRAM), external micro-DIMM SDRAM, smartcard memory such as tamper resistant module in the form of a universal integrated circuit card (UICC) including one or more subscriber identity modules (SIMs), such as a USIM and / or ISIM, other memory, or any combination thereof. The UICC may for example be an embedded UICC (eUlCC), integrated UICC (iUICC) or a removable UICC commonly known as ‘SIM card.’ Memory 1010 may allow UE 1000 to access instructions, application programs and the like, stored on transitory or non-transitory memory media, to off-load data, or to upload data. An article of manufacture, such as one utilizing a communication system may be tangibly embodied as or in memory 1010, which may be or comprise a device-readable storage medium.

[0191] Processing circuitry 1002 may be configured to communicate with an access network or other network using communication interface 1012. Communication interface 1012 may comprise one or more communication subsystems and may include or be communicatively coupled to antenna 1022. Communication interface 1012 may include one or more transceivers used to communicate, such as by communicating with one or more remote transceivers of another device capable of wireless communication (e.g., another UE ora network node in an access network). Each transceiver may include transmitter 1018 and / or receiver 1020 appropriate to provide network communications (e.g., optical, electrical, frequency allocations, and so forth). Moreover, transmitter 1018 and receiver 1020 may be coupled to one or more antennas (e.g., 1022) and may share circuit components, software or firmware, or alternatively be implemented separately.

[0192] In the illustrated embodiment, communication functions of communication interface 1012 may include cellular communication, Wi-Fi communication, LPWAN communication, data communication, voice communication, multimedia communication, short-range communications such as Bluetooth, near-field communication, location-based communicationsuch as the use of the global positioning system (GPS) to determine a location, another like communication function, or any combination thereof. Communications may be implemented in according to one or more communication protocols and / or standards, such as IEEE 1002.11 , Code Division Multiplexing Access (CDMA), Wideband Code Division Multiple Access (WCDMA), GSM, LTE, New Radio (NR), UMTS, WiMax, Ethernet, transmission control protocol / internet protocol (TCP / IP), synchronous optical networking (SONET), Asynchronous Transfer Mode (ATM), QUIC, Hypertext Transfer Protocol (HTTP), and so forth.

[0193] Regardless of the type of sensor, a UE may provide an output of data captured by its sensors, through its communication interface 1012, via a wireless connection to a network node. Data captured by sensors of a UE can be communicated through a wireless connection to a network node via another UE. The output may be periodic (e.g., once every 12 minutes if it reports the sensed temperature), random (e.g., to even out the load from reporting from several sensors), in response to a triggering event (e.g., an alert is sent when moisture is detected), in response to a request (e.g., a user initiated request), or a continuous stream (e.g., a live video feed of a patient).

[0194] As another example, a UE comprises an actuator, a motor, or a switch, related to a communication interface configured to receive wireless input from a network node via a wireless connection. In response to the received wireless input the states of the actuator, the motor, or the switch may change. For example, the UE may comprise a motor that adjusts the control surfaces or rotors of a drone in flight according to the received input or to a robotic arm performing a medical procedure according to the received input.

[0195] A UE, when in the form of an Internet of Things (loT) device, may be a device for use in one or more application domains, these domains comprising, but not limited to, city wearable technology, extended industrial application and healthcare. Non-limiting examples of such an loT device are a device which is or which is embedded in: a connected refrigerator or freezer, aTV, a connected lighting device, an electricity meter, a robot vacuum cleaner, a voice controlled smart speaker, a home security camera, a motion detector, a thermostat, a smoke detector, a door / window sensor, a flood / moisture sensor, an electrical door lock, a connected doorbell, an air conditioning system like a heat pump, an autonomous vehicle, a surveillance system, a weather monitoring device, a vehicle parking monitoring device, an electric vehicle charging station, a smartwatch, a fitness tracker, a head-mounted display for Augmented Reality (AR) or Virtual Reality (VR), a wearable for tactile augmentation or sensory enhancement, a water sprinkler, an animal- or item-tracking device, a sensor for monitoring a plant or animal, an industrial robot, an Unmanned Aerial Vehicle (UAV), and any kind of medical device, like a heart rate monitor or a remote controlled surgical robot. A UE in the form of an loT device comprises circuitry and / or software in dependence of the intended application of the loT device in addition to other components as described in relation to UE 1000 shown in Figure 10.

[0196] As yet another specific example, in an loT scenario, a UE may represent a machine or other device that performs monitoring and / or measurements, and transmits the results of such monitoring and / or measurements to another UE and / or a network node. The UE may in this case be an M2M device, which may in a 3GPP context be referred to as an MTC device. As one particular example, the UE may implement the 3GPP NB-loT standard. In other scenarios, a UE may represent a vehicle, such as a car, a bus, a truck, a ship and an airplane, or other equipment that is capable of monitoring and / or reporting on its operational status or other functions associated with its operation.

[0197] In practice, any number of UEs may be used together with respect to a single use case. For example, a first UE might be or be integrated in a drone and provide the drone’s speed information (obtained through a speed sensor) to a second UE that is a remote controller operating the drone. When the user makes changes from the remote controller, the first UE may adjust the throttle on the drone (e.g., by controlling an actuator) to increase or decrease thedrone’s speed. The first and / or the second UE can also include more than one of the functionalities described above. For example, a UE might comprise the sensor and the actuator, and handle communication of data for both the speed sensor and the actuators.

[0198] Figure 11 shows a network node 1100 in accordance with some embodiments. Examples of network nodes include, but are not limited to, access points (e.g., radio access points) and base stations (e.g., radio base stations, Node Bs, eNBs, and gNBs).

[0199] Base stations may be categorized based on the amount of coverage they provide (or, stated differently, their transmit power level) and so, depending on the provided amount of coverage, may be referred to as femto base stations, pico base stations, micro base stations, or macro base stations. A base station may be a relay node or a relay donor node controlling a relay. A network node may also include one or more (or all) parts of a distributed radio base station such as centralized digital units and / or remote radio units (RRUs), sometimes referred to as Remote Radio Heads (RRHs). Such remote radio units may or may not be integrated with an antenna as an antenna integrated radio. Parts of a distributed radio base station may also be referred to as nodes in a distributed antenna system (DAS).

[0200] Other examples of network nodes include multiple transmission point (multi-TRP) 5G access nodes, multi-standard radio (MSR) equipment such as MSR BSs, network controllers such as radio network controllers (RNCs) or base station controllers (BSCs), base transceiver stations (BTSs), transmission points, transmission nodes, multi-cell / multicast coordination entities (MCEs), Operation and Maintenance (O&M) nodes, Operations Support System (OSS) nodes, Self-Organizing Network (SON) nodes, positioning nodes (e.g., Evolved Serving Mobile Location Centers (E-SMLCs)), and / or Minimization of Drive Tests (MDTs).

[0201] Network node 1100 includes processing circuitry 1102, memory 1104, communication interface 1106, and power source 1108. Network node 1100 may be composed of multiplephysically separate components (e.g., a NodeB component and a RNC component, or a BTS component and a BSC component, etc.), which may each have their own respective components. In certain scenarios in which network node 1100 comprises multiple separate components (e.g., BTS and BSC components), one or more of the separate components may be shared among several network nodes. For example, a single RNC may control multiple NodeBs. In such a scenario, each unique NodeB and RNC pair, may in some instances be considered a single separate network node. In some embodiments, network node 1100 may be configured to support multiple radio access technologies (RATs). In such embodiments, some components may be duplicated (e.g., separate memory 1104 for different RATs) and some components may be reused (e.g., a same antenna 1110 may be shared by different RATs). Network node 1100 may also include multiple sets of the various illustrated components for different wireless technologies integrated into network node 1100, for example GSM, WCDMA, LTE, NR, WiFi, Zigbee, Z-wave, LoRaWAN, Radio Frequency Identification (RFID) or Bluetooth wireless technologies. These wireless technologies may be integrated into the same or different chip or set of chips and other components within network node 1100.

[0202] Processing circuitry 1102 may comprise a combination of one or more of a microprocessor, controller, microcontroller, central processing unit, digital signal processor, application-specific integrated circuit, field programmable gate array, or any other suitable computing device, resource, or combination of hardware, software and / or encoded logic operable to provide, either alone or in conjunction with other network node 1100 components, such as memory 1104, to provide network node 1100 functionality.

[0203] In some embodiments, processing circuitry 1102 includes a system on a chip (SOC). In some embodiments, processing circuitry 1102 includes one or more of radio frequency (RF) transceiver circuitry 1112 and baseband processing circuitry 1114. In some embodiments, RF transceiver circuitry 1112 and baseband processing circuitry 1114 may be on separate chips (orsets of chips), boards, or units, such as radio units and digital units. In alternative embodiments, part or all of RF transceiver circuitry 1112 and baseband processing circuitry 1114 may be on the same chip or set of chips, boards, or units.

[0204] Processing circuitry 1102 may be configured to cause the network node 1100 to perform the methods as described herein, such as described with reference to Figure 7, or Figure 8.

[0205] Memory 1104 may comprise any form of volatile or non-volatile computer-readable memory including, without limitation, persistent storage, solid-state memory, remotely mounted memory, magnetic media, optical media, random access memory (RAM), read-only memory (ROM), mass storage media (for example, a hard disk), removable storage media (for example, a flash drive, a Compact Disk (CD) ora Digital Video Disk (DVD)), and / or any other volatile or nonvolatile, non-transitory device-readable and / or computer-executable memory devices that store information, data, and / or instructions that may be used by processing circuitry 1102. Memory 1104 may store any suitable instructions, data, or information, including a computer program, software, an application including one or more of logic, rules, code, tables, and / or other instructions (collectively denoted computer program product 1104a) capable of being executed by processing circuitry 1102 and utilized by network node 1100. Memory 1104 may be used to store any calculations made by processing circuitry 1102 and / or any data received via communication interface 1106. In some embodiments, processing circuitry 1102 and memory 1104 is integrated.

[0206] Communication interface 1106 is used in wired or wireless communication of signaling and / or data between a network node, access network, and / or UE. As illustrated, communication interface 1106 comprises port(s) / terminal(s) 1116 to send and receive data, for example to and from a network over a wired connection. Communication interface 1106 also includes radio front-end circuitry 1118 that may be coupled to, or in certain embodiments a part of, antenna 1110. Radio front-end circuitry 1118 comprises filters 1120 and amplifiers 1122. Radio front-end circuitry 1118 may be connected to antenna 1110 and processing circuitry 1102. The radio front-end circuitry may be configured to condition signals communicated between antenna 1110 and processing circuitry 1102. Radio front-end circuitry 1118 may receive digital data that is to be sent out to other network nodes or UEs via a wireless connection. Radio front-end circuitry 1118 may convert the digital data into a radio signal having the appropriate channel and bandwidth parameters using a combination of filters 1120 and / or amplifiers 1122. The radio signal may then be transmitted via antenna 1110. Similarly, when receiving data, antenna 1110 may collect radio signals which are then converted into digital data by radio front-end circuitry 1118. The digital data may be passed to processing circuitry 1102. In other embodiments, the communication interface may comprise different components and / or different combinations of components.

[0207] In certain alternative embodiments, network node 1100 does not include separate radio frontend circuitry 1118, instead, processing circuitry 1102 includes radio front-end circuitry and is connected to antenna 1110. Similarly, in some embodiments, all or some of RF transceiver circuitry 1112 is part of communication interface 1106. In still other embodiments, communication interface 1106 includes one or more ports or terminals 1116, radio front-end circuitry 1118, and RF transceiver circuitry 1112, as part of a radio unit (not shown), and communication interface 1106 communicates with the baseband processing circuitry 1114, which is part of a digital unit (not shown).

[0208] Antenna 1110 may include one or more antennas, or antenna arrays, configured to send and / or receive wireless signals. Antenna 1110 may be coupled to radio front-end circuitry 1118 and may be any type of antenna capable of transmitting and receiving data and / or signals wirelessly. In certain embodiments, antenna 1110 is separate from network node 1100 and connectable to network node 1100 through an interface or port.Antenna 1110, communication interface 1106, and / or processing circuitry 1102 may be configured to perform any receiving operations and / or certain obtaining operations described herein as being performed by the network node. Any information, data and / or signals may be received from a UE, another network node and / or any other network equipment. Similarly, antenna 1110, communication interface 1106, and / or processing circuitry 1102 may be configured to perform any transmitting operations described herein as being performed by the network node. Any information, data and / or signals may be transmitted to a UE, another network node and / or any other network equipment.

[0209] Power source 1108 provides power to the various components of network node 1100 in a form suitable for the respective components (e.g., at a voltage and current level needed for each respective component). Power source 1108 may further comprise, or be coupled to, power management circuitry to supply the components of network node 1100 with power for performing the functionality described herein. For example, network node 1100 may be connectable to an external power source (e.g., the power grid, an electricity outlet) via an input circuitry or interface such as an electrical cable, whereby the external power source supplies power to power circuitry of power source 1108. As a further example, power source 1108 may comprise a source of power in the form of a battery or battery pack which is connected to, or integrated in, power circuitry. The battery may provide backup power should the external power source fail.

[0210] Embodiments of network node 1100 may include additional components beyond those shown in Figure 11 for providing certain aspects of the network node’s functionality, including any of the functionality described herein and / or any functionality necessary to support the subject matter described herein. For example, network node 1100 may include user interface equipment to allow input of information into network node 1100 and to allow output ofinformation from network node 1100. This may allow a user to perform diagnostic, maintenance, repair, and other administrative functions for network node 1100.

[0211] Figure 12 is a block diagram illustrating a virtualization environment 1200 in which functions implemented by some embodiments may be virtualized. In the present context, virtualizing means creating virtual versions of apparatuses or devices which may include virtualizing hardware platforms, storage devices and networking resources. As used herein, virtualization can be applied to any device described herein, or components thereof, and relates to an implementation in which at least a portion of the functionality is implemented as one or more virtual components. Some or all of the functions described herein may be implemented as virtual components executed by one or more virtual machines (VMs) implemented in one or more virtual environments 1200 hosted by one or more of hardware nodes, such as a hardware computing device that operates as a network node, UE, core network node, or host. Further, in embodiments in which the virtual node does not require radio connectivity (e.g., a core network node or host), then the node may be entirely virtualized.

[0212] Applications 1202 (which may alternatively be called software instances, virtual appliances, network functions, virtual nodes, virtual network functions, etc.) are run in the virtualization environment 1200 to implement some of the features, functions, and / or benefits of some of the embodiments disclosed herein.

[0213] Hardware 1204 includes processing circuitry, memory that stores software and / or instructions (collectively denoted computer program product 1204a) executable by hardware processing circuitry, and / or other hardware devices as described herein, such as a network interface, input / output interface, and so forth. Software may be executed by the processing circuitry to instantiate one or more virtualization layers 1206 (also referred to as hypervisors or virtual machine monitors (VMMs)), provide VMs 1208a-b (one or more of which may be generally referred to as VMs 1208), and / or perform any of the functions, features and / or benefitsdescribed in relation with some embodiments described herein. The virtualization layer 1206 may present a virtual operating platform that appears like networking hardware to VMs 1208.

[0214] VMs 1208 comprise virtual processing, virtual memory, virtual networking or interface and virtual storage, and may be run by a corresponding virtualization layer 1206. Different embodiments of the instance of a virtual appliance 1202 may be implemented on one or more of VMs 1208, and the implementations may differ. Virtualization of the hardware is in some contexts referred to as network function virtualization (NFV). NFV may be used to consolidate many network equipment types onto industry standard high volume server hardware, physical switches, and physical storage, which can be located in data centers, and customer premise equipment.

[0215] In the context of NFV, each VM 1208 may be a software implementation of a physical machine that runs programs as if they were executingon a physical, non-virtualized machine. Each of VMs 1208, and that part of hardware 1204 that executes that VM, be it hardware dedicated to that VM and / or hardware shared by that VM with others of the VMs, forms separate virtual network elements. Still in the context of NFV, a virtual network function is responsible for handling specific network functions that run in one or more VMs 1208 on top of hardware 1204 and corresponds to application 1202.

[0216] Hardware 1204 may be implemented in a standalone network node with generic or specific components. Hardware 1204 may implement some functions via virtualization. Alternatively, hardware 1204 may be part of a larger cluster of hardware (e.g., such as in a data center or CPE) where many hardware nodes work together and are managed via management and orchestration 1210, which, among others, oversees lifecycle management of applications 1202. In some embodiments, hardware 1204 is coupled to one or more radio units that each include one or more transmitters and one or more receivers that may be coupled to one or more antennas. Radio units may communicate directly with other hardware nodes via one or moreappropriate network interfaces and may be used in combination with the virtual components to provide a virtual node with radio capabilities, such as a radio access node or a base station. In some embodiments, some signaling can be provided with the use of control system 1212 which may alternatively be used for communication between hardware nodes and radio units.

[0217] The foregoing merely illustrates the principles of the disclosure. Various modifications and alterations to the described embodiments will be apparent to those skilled in the art in view of the teachings herein. It will thus be appreciated that those skilled in the art will be able to devise numerous systems, arrangements, and procedures that, although not explicitly shown or described herein, embody the principles of the disclosure and can be thus within the spirit and scope of the disclosure. Various embodiments can be used together with one another, as well as interchangeably therewith, as should be understood by those having ordinary skill in the art.

[0218] The term unit, as used herein, can have conventional meaning in the field of electronics, electrical devices and / or electronic devices and can include, for example, electrical and / or electronic circuitry, devices, modules, processors, memories, logic solid state and / or discrete devices, computer programs or instructions for carrying out respective tasks, procedures, computations, outputs, and / or displaying functions, and so on, as such as those that are described herein.

[0219] Any appropriate steps, methods, features, functions, or benefits disclosed herein may be performed through one or more functional units or modules of one or more virtual apparatuses. Each virtual apparatus may comprise a number of these functional units. These functional units may be implemented via processing circuitry, which may include one or more microprocessor or microcontrollers, as well as other digital hardware, which may include Digital Signal Processor (DSPs), special-purpose digital logic, and the like. The processing circuitry may be configured to execute program code stored in memory, which may include one or several types of memory such as Read Only Memory (ROM), Random Access Memory (RAM), cache memory,flash memory devices, optical storage devices, etc. Program code stored in memory includes program instructions for executing one or more telecommunications and / or data communications protocols as well as instructions for carrying out one or more of the techniques described herein. In some implementations, the processing circuitry may be used to cause the respective functional unit to perform corresponding functions according to one or more embodiments of the present disclosure.

[0220] As described herein, device and / or apparatus can be represented by a semiconductor chip, a chipset, or a (hardware) module comprising such chip or chipset; this, however, does not exclude the possibility that a functionality of a device or apparatus, instead of being hardware implemented, be implemented as a software module such as a computer program or a computer program product comprising executable software code portions for execution or being run on a processor. Furthermore, functionality of a device or apparatus can be implemented by any combination of hardware and software. A device or apparatus can also be regarded as an assembly of multiple devices and / or apparatuses, whether functionally in cooperation with or independently of each other. Moreover, devices and apparatuses can be implemented in a distributed fashion throughout a system, so long as the functionality of the device or apparatus is preserved. Such and similar principles are considered as known to a skilled person.

[0221] Furthermore, functions described herein as being performed by a wireless device or a network node may be distributed over a plurality of wireless devices and / or network nodes. In other words, it is contemplated that the functions of the network node and wireless device described herein are not limited to performance by a single physical device and, in fact, can be distributed among several physical devices.

[0222] In addition, certain terms used in the present disclosure, includingthe specification, drawings and embodiments thereof, can be used synonymously in certain instances, including, but notlimited to, e.g., data and information. It should be understood that, while these words and / or other words that can be synonymous to one another, can be used synonymously herein, that there can be instances when such words can be intended to not be used synonymously.

[0223] Further, to the extent that the prior art knowledge has not been explicitly incorporated by reference herein above, it is explicitly incorporated herein in its entirety. All publications referenced are incorporated herein by reference in their entireties.

[0224] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. It will be further understood that terms used herein should be interpreted as having a meaning that is consistent with their meaning in the context of this specification and the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0225] In addition, certain terms used in the present disclosure, including the specification and drawings, can be used synonymously in certain instances (e.g., “data” and “information”). It should be understood, that although these terms (and / or other terms that can be synonymous to one another) can be used synonymously herein, there can be instances when such words can be intended to not be used synonymously.

[0226] EXAMPLE EMBODIMENTS

[0227] Examples of the inventive techniques, apparatuses, and systems described herein include, but are not limited to, the following enumerated embodiments:

[0228] 1. A method, in a user equipment, UE, for handling measurements of cells associated with Layer-1 / Layer-2-triggered mobility, LTM, in a wireless network, the method comprising:

[0229] receiving, from a network node in the wireless network, measurement information specifying one or more measurement resources for one or more secondarycells, SCells, that are in a same group as an LTM candidate cell configured for the UE but that are not configured as LTM candidate cells for the UE; and performing Layer-1 measurements on at least one of the measurement resources for at least one of the one or more SCells.

[0230] 2. The method of example embodiment 1 wherein said performing Layer-1 measurements comprises performing Layer-1 Received Signal Reference Power, L1-RSRP, measurements.

[0231] 3. The method of example embodiment 1 or 2, further comprising reporting one or more of the Layer-1 measurements to the wireless network, using only lower layer signaling.

[0232] 4. The method of example embodiment 3, further comprising:

[0233] receiving, from the network, a lower layer indication to activate, deactivate, or release at least one of the one or more SCells, in response to said reporting.

[0234] 5. The method of any one of example embodiments 1-4, wherein the measurement information comprises a measurement resource set for at least one of the one or more SCells.

[0235] 6. The method of any one of example embodiments 1-5, wherein the measurement information identifies two or more reference signals and / or beams and includes an indication of which reference signal and / or beam belongs to which SCell or which Special Cell, SPCell, in the same group as the LTM candidate cell configured for the UE.

[0236] 7. The method of any one of example embodiments 1-6, wherein the measurement information comprises a measurement configuration that explicitly identifies one or more reference signalsand / or beams and explicitly associates the identified one or more reference signals and / or beams with an SCell in the same group as the LTM candidate cell configured for the UE.

[0237] 8. The method of anyone of example embodiments 1-7, wherein the measurement information identifies at least one of the one or more SCells with an SCell index or a physical cell identifier, PCI.

[0238] 9. The method of any one of example embodiments 1-8, wherein the measurement information identifies at least one measurement resource using a Synchronization Signal Block, SSB, index and / or a Channel State Information Reference Signal, CSI-RS, index.

[0239] 10. The method of anyone of example embodiments 1-9, wherein the measurement information comprises information indicating one or more constraints regarding which SCells to be measured and / or how many SCells to be measured.

[0240] 11. A method, in a first network node, for handling measurements of cells associated with Layer-1 / Layer-2-triggered mobility, LTM, in a wireless network the method comprising:

[0241] sending, to a UE, measurement information specifying one or more measurement resources for one or more secondary cells, SCells, that are in a same group as an LTM candidate cell configured for the UE but that are not configured as LTM candidate cells forthe UE.

[0242] 12. The method of example embodiment 11 , further comprising:

[0243] receiving, from the UE, one or more Layer-1 measurements relating to at least one of the one or more SCells, via lower layer signaling.13. The method of example embodiment 12, further comprising:

[0244] determining to activate, deactivate, or release at least one of the one or more SCells, based on the Layer-1 measurements.

[0245] 14. The method of any one of example embodiments 11-13, wherein the method comprises requesting measurement information from a second network node that provides the LTM candidate cell configured for the UE and receiving at least some of the measurement information sent to the UE from the second network node.

[0246] 15. The method of any one of example embodiments 11-14, wherein the measurement information sent to the UE comprises a measurement resource set for at least one of the one or more SCells.

[0247] 16. The method of any one of example embodiments 11-15, wherein the measurement information sent to the UE identifies two or more reference signals and / or beams and includes an indication of which reference signal and / or beam belongs to which SCell or which Special Cell, SPCell, in the same group as the LTM candidate cell configured for the UE.

[0248] 17. The method of any one of example embodiments 11-16, wherein the measurement information sent to the UE comprises a measurement configuration that explicitly identifies one or more reference signals and / or beams and explicitly associates the identified one or more reference signals and / or beams with an SCell in the same group as the LTM candidate cell configured for the UE.18. The method of any one of example embodiments 11-17, wherein the measurement information sent to the UE identifies at least one of the one or more SCells with an SCell index or a physical cell identifier, PCI.

[0249] 19. The method of any one of example embodiments 11-18, wherein the measurement information sent to the UE identifies at least one measurement resource using a Synchronization Signal Block, SSB, index and / or a Channel State Information Reference Signal, CSI-RS, index.

[0250] 20. The method of any one of example embodiments 11-19, wherein the measurement information sent to the UE comprises information indicating one or more constraints regarding which SCells to be measured and / or how many SCells to be measured.

[0251] 21. A method, in a second network node, for handling measurements of cells associated with Layer-1 / Layer-2-triggered mobility, LTM, in a wireless network the method comprising:

[0252] receiving, from a first network node, a request for measurement information specifying one or more measurement resources for one or more secondary cells, SCells, that are in a same group as an LTM candidate cell configured for a user equipment, UE, and provided by the second network node, but that are not configured as LTM candidate cells for the UE; and

[0253] sending, to the first network node, measurement information specifying at least one measurement resource for at least one SCell.

[0254] 22. The method of example embodiment 21 , wherein the measurement information sent to the first network node comprises a measurement resource set for at least one of the one or more SCells.23. The method of example embodiment 21 or 22, wherein the measurement information sent to the first network node identifies two or more reference signals and / or beams and includes an indication of which reference signal and / or beam belongs to which SCell or which Special Cell, SPCell, in the same group as the LTM candidate cell configured for the UE.

[0255] 24. The method of anyone of example embodiments 21-23, wherein the measurement information sent to the first network node comprises a measurement configuration that explicitly identifies one or more reference signals and / or beams and explicitly associates the identified one or more reference signals and / or beams with an SCell in the same group as the LTM candidate cell configured for the UE.

[0256] 25. The method of anyone of example embodiments 21-24, wherein the measurement information sent to the first network node identifies at least one of the one or more SCells with an SCell index or a physical cell identifier, PCI.

[0257] 26. The method of anyone of example embodiments 21-25, wherein the measurement information sent to the first network node identifies at least one measurement resource using a Synchronization Signal Block, SSB, index and / or a Channel State Information Reference Signal, CSI-RS, index.

[0258] 27. The method of anyone of example embodiments 21-26, wherein the measurement information sent to the first network node comprises information indicating one or more constraints regarding which SCells to be measured and / or how many SCells to be measured.

[0259] 28. A user equipment, UE (800), comprising:communication interface circuitry (812) configured to communicate with a wireless network via at least one serving cell; and

[0260] processing circuitry (802) operably coupled to the communication interface circuitry (812), wherein the processing circuitry (802) and communication interface circuitry (812) are configured to:

[0261] receive, from a network node in the wireless network, measurement information specifying one or more measurement resources for one or more secondary cells, SCells, that are in a same group as an LTM candidate cell configured for the UE but that are not configured as LTM candidate cells for the UE; and

[0262] perform Layer-1 measurements on at least one of the measurement resources for at least one of the one or more SCells.

[0263] 29. The UE (800) of example embodiment 28, wherein the processing circuitry (802) and communication interface circuitry (812) are configured to carryout a method according to any of example embodiments 2-10.

[0264] 30. A user equipment, UE, adapted to carry out a method according to any of example embodiments 1-10.

[0265] 31. A network node (900), comprising:

[0266] communication interface circuitry (906) configured to communicate with one or more user equipments, UEs, via at least one serving cell; and

[0267] processing circuitry (902) operably coupled to the communication interface circuitry, wherein the processing circuitry (902) and communication interface circuitry (906) are configured to:send, to a UE, measurement information specifying one or more measurement resources for one or more secondary cells, SCells, that are in a same group as an LTM candidate cell configured for the UE butthat are not configured as LTM candidate cells for the UE.

[0268] 32. The first network node of example embodiment 31 , wherein the processing circuitry (902) and communication interface circuitry (906) are configured to carryout a method according to any of example embodiments 12-20.

[0269] 33. A first network node (900), adapted to carryout a method according to any of example embodiments 11-20.

[0270] 34. A second network node, comprising:

[0271] communication interface circuitry configured to communicate with one or more other network nodes; and

[0272] processing circuitry operably coupled to the communication interface circuitry, wherein the processing circuitry and communication interface circuitry are configured to: receive, from a first network node, a request for measurement information specifying one or more measurement resources for one or more secondary cells, SCells, that are in a same group as an LTM candidate cell configured fora user equipment, UE, and provided by the second network node, but that are not configured as LTM candidate cells for the UE; and

[0273] send, to the first network node, measurement information specifying at least one measurement resource for at least one SCell.35. The second network node of example embodiment 34, wherein the processing circuitry and communication interface circuitry are configured to carry out a method according to any of example embodiments 22-27.

[0274] 36. A second network node, adapted to carry out a method according to any of example embodiments 21-27.

[0275] ABBREVIATIONS

[0276] 5GC or5GCN 5G Core Network

[0277] ARFCN Absolute Radio Frequency Channel Number

[0278] CA Carrier Aggregation

[0279] CC Component Carrier

[0280] C-CU Candidate CU

[0281] C-DU Candidate DU

[0282] CE Control Element

[0283] CGI Cell Global Identity

[0284] CHO Conditional Handover

[0285] CLTM Conditional LTM

[0286] CPC Conditional PSCell Change

[0287] CPA Conditional PSCell Addition

[0288] CPAC Conditional PSCell Addition orChange

[0289] CN Core Network

[0290] CP Control Plane

[0291] CRI CSI-RS Resource Indicator

[0292] CSI Channel State Information

[0293] CU Central Unit

[0294] DC Direct CurrentDC Dual Connectivity

[0295] DCI Downlink Control Information

[0296] DL Downlink

[0297] DU Distributed Unit

[0298] F1 Interface between Central Unit and Distributed Unit gNB NR base station

[0299] IE Information Element

[0300] LTE Long Term Evolution

[0301] LTM L1 / L2-Triggered Mobility

[0302] MCG Master Cell Group

[0303] MAC Medium Access Control

[0304] MACCE MAC Control Element

[0305] MN Master Node

[0306] MR-DC Multi-Radio Dual Connectivity

[0307] NG-RAN Next Generation Radio Access Network

[0308] NR New Radio

[0309] PCell Primary Cell (in LTE) or Primary MCG Cell (in NR)

[0310] PCI Physical Cell Identity

[0311] PDCCH Physical Downlink Control Channel

[0312] PDSCH Physical Downlink Shared Channel

[0313] PSCell Primary Secondary Cell (in LTE) or Primary SCG Cell (in NR) PUCCH Physical Uplink Control Channel

[0314] PUSCH Physical Uplink Shared Channel

[0315] RRC Radio Resource Control

[0316] RS Reference Signal

[0317] RSRP Reference Signal Received PowerRSRQ Reference Signal Received Quality

[0318] RSSI Received Signal Strength Indicator SCell Secondary Cell

[0319] S-CU Source DU

[0320] S-CU Source CU

[0321] SINR Signal to Interference plus Noise Ratio

[0322] SN Secondary Node

[0323] SNR Signal to Noise Ratio

[0324] SR Scheduling Request

[0325] SSB Synchronization Signal Block

[0326] SSBRI SSB Resource Indicator

[0327] SpCell Special Cell, the primary cell of MCG or SCG TA Timing Advance

[0328] TAT Time Alignment Timer

[0329] TCI Transmission Configuration Indication TRS Tracking Reference Signal

[0330] TTT Time to trigger

[0331] UCI Uplink Control Information

[0332] UE User Equipment

[0333] UL Uplink

[0334] UL-SCH UplinkShared Channel

[0335] UP User Plane

[0336] Xn Interface between base stations

Claims

CLAIMS1. A method, in a user equipment, UE, for handling measurements of cells associated with Layer-1 / Layer-2-triggered mobility, LTM, in a wireless network, the method comprising:receiving, from a network node in the wireless network, measurement information specifying one or more measurement resources for one or more secondary cells, SCells, wherein the one or more SCells are in a same group as an LTM candidate cell configured for the UE , wherein the one or more SCells are not configured as LTM candidate cells for the UE; andperforming Layer-1 measurements on at least one of the measurement resources for at least one of the one or more SCells.

2. The method of claim 1 , wherein said performing Layer-1 measurements comprises performing Layer-1 Received Signal Reference Power, L1-RSRP, measurements.

3. The method of claims 1 or 2, further comprising reporting one or more of the Layer-1 measurements to the wireless network, using only lower layer signaling.

4. The method of claim3, further comprising:receiving, from the wireless network, a lower layer indication to activate, deactivate, or release at least one of the one or more SCells, in response to said reporting.

5. The method of anyone of claims 1-4, wherein the measurement information comprises a measurement resource set for at least one of the one or more SCells.

6. The method of anyone of claims 1-5, wherein the measurement information identifies two or more reference signals and / or beams and includes an indication of which reference signaland / or beam belongs to which SCell or which Special Cell, SPCell, in the same group as the LTM candidate cell configured for the UE.

7. The method of anyone of claims 1-6, wherein the measurement information comprises a measurement configuration that explicitly identifies one or more reference signals and / or beams, and explicitly associates the identified one or more reference signals and / or beams with an SCell in the same group as the LTM candidate cell configured for the UE.

8. The method of anyone of claims 1-7, wherein the measurement information identifies at least one of the one or more SCells with an SCell index, or a physical cell identifier, PCI.

9. The method of anyone of claims 1-8, wherein the measurement information identifies at least one measurement resource using a Synchronization Signal Block, SSB, index, and / or a Channel State Information Reference Signal, CSI-RS, index.

10. The method of anyone of claims 1-9, wherein the measurement information comprises information indicating one or more constraints regarding which SCells to be measured and / or how many SCells to be measured.

11. A method, in a first network node, for handling measurements of cells associated with Layer-1 / Layer-2-triggered mobility, LTM, in a wireless network the method comprising:sending, to a User Equipment, UE, measurement information specifying one or more measurement resources for one or more secondary cells, SCells, wherein the one or more SCells are in a same group as an LTM candidate cell configured for the UE, wherein the one or more SCells are not configured as LTM candidate cells for the UE.

12. The method of claim 11 , further comprising:receiving, from the UE, one or more Layer-1 measurements relating to at least one of the one or more SCells, via lower layer signaling.

13. The method of claim 12, further comprising:determining to activate, deactivate, or release at least one of the one or more SCells, based on the Layer-1 measurements.

14. The method of any one of claims 11-13, wherein the method comprises:requesting measurement information from a second network node that provides the LTM candidate cell configured for the UE; andreceiving at least some of the measurement information sent to the UE from the second network node.

15. The method of anyone of claims 11-14, wherein the measurement information sent to the UE comprises a measurement resource set for at least one of the one or more SCells.

16. The method of anyone of claims 11-15, wherein the measurement information sent to the UE identifies two or more reference signals and / or beams, and includes an indication of which reference signal and / or beam belongs to which SCell or which Special Cell, SPCell, in the same group as the LTM candidate cell configured for the UE.

17. The method of anyone of claims 11-16, wherein the measurement information sent to the UE comprises a measurement configuration that explicitly identifies one or more referencesignals and / or beams, and explicitly associates the identified one or more reference signals and / or beams with an SCell in the same group as the LTM candidate cell configured for the UE.

18. The method of anyone of claims 11-17, wherein the measurement information sent to the UE identifies at least one of the one or more SCells with an SCell index, or a physical cell identifier, PCI.

19. The method of anyone of claims 11-18, wherein the measurement information sent to the UE identifies at least one measurement resource using a Synchronization Signal Block, SSB, index, and / or a Channel State Information Reference Signal, CSI-RS, index.

20. The method of anyone of claims 11-19, wherein the measurement information sent to the UE comprises information indicating one or more constraints regarding which SCells to be measured and / or how many SCells to be measured.

21. A method, in a second network node, for handling measurements of cells associated with Layer-1 / Layer-2-triggered mobility, LTM, in a wireless network the method comprising:receiving, from a first network node, a request for measurement information specifying one or more measurement resources for one or more secondary cells, SCells, wherein the one or more SCells are in a same group as an LTM candidate cell configured for a user equipment, UE, wherein the one or more SCells are not configured as LTM candidate cells for the UE; andsending, to the first network node, measurement information specifying at least one measurement resource for at least one SCell.

22. The method of claim 21 , wherein the measurement information sent to the first network node comprises a measurement resource set for at least one of the one or more SCells.

23. The method of claims 21 or 22, wherein the measurement information sent to the first network node identifies two or more reference signals and / or beams, and includes an indication of which reference signal and / or beam belongs to which SCell or which Special Cell, SPCell, in the same group as the LTM candidate cell configured for the UE.

24. The method of anyone of claims 21-23, wherein the measurement information sent to the first network node comprises a measurement configuration that explicitly identifies one or more reference signals and / or beams, and explicitly associates the identified one or more reference signals and / or beams with an SCell in the same group as the LTM candidate cell configured for the UE.

25. The method of anyone of claims 21-24, wherein the measurement information sent to the first network node identifies at least one of the one or more SCells with an SCell index, or a physical cell identifier, PCI.

26. The method of anyone of claims 21-25, wherein the measurement information sent to the first network node identifies at least one measurement resource using a Synchronization Signal Block, SSB, index, and / or a Channel State Information Reference Signal, CSI-RS, index.

27. The method of anyone of claims 21-26, wherein the measurement information sent to the first network node comprises information indicating one or more constraints regarding which SCells to be measured and / or how many SCells to be measured.

28. A user equipment, UE (800), comprising:communication interface circuitry (812) configured to communicate with a wireless network via at least one serving cell; andprocessing circuitry (802) operably coupled to the communication interface circuitry (812), wherein the processing circuitry (802) and communication interface circuitry (812) are configured to:receive, from a network node in the wireless network, measurement information specifying one or more measurement resources for one or more secondary cells, SCells, wherein the one or more SCells are in a same group as an LTM candidate cell configured for the UE, wherein the one or more SCells are not configured as LTM candidate cells for the UE; and perform Layer-1 measurements on at least one of the measurement resources for at least one of the one or more SCells.

29. The UE (800) of example claim 28, wherein the processing circuitry (802) and communication interface circuitry (812) are configured to carryout a method according to any of claims 2-10.

30. A user equipment, UE, adapted to carryout a method according to any of claims 1-10.

31. A first network node (900), comprising:communication interface circuitry (906) configured to communicate with one or more user equipments, UEs, via at least one serving cell; andprocessing circuitry (902) operably coupled to the communication interface circuitry, wherein the processing circuitry (902) and communication interface circuitry (906) are configured to:send, to a UE, measurement information specifying one or more measurement resources for one or more secondary cells, SCells, wherein the one or more SCells are in a same group as an LTM candidate cell configured for the UE, wherein the one or more SCells are not configured as LTM candidate cells forthe UE.

32. The first network node of claim 31 , wherein the processing circuitry (902) and communication interface circuitry (906) are configured to carryout a method according to any of claims 12-20.

33. A first network node (900), adapted to carryout a method according to any of claims 11-20.

34. A second network node, comprising:communication interface circuitry configured to communicate with one or more other network nodes; andprocessing circuitry operably coupled to the communication interface circuitry, wherein the processing circuitry and communication interface circuitry are configured to: receive, from a first network node, a request for measurement information specifying one or more measurement resources for one or more secondary cells, SCells, wherein the one or more SCells are in a same group as an LTM candidate cell configured for a user equipment, UE, and provided by the second network node, wherein the one or more SCells are not configured as LTM candidate cells forthe UE; andsend, to the first network node, measurement information specifying at least one measurement resource for at least one SCell.

35. The second network node of claim 34, wherein the processing circuitry and communication interface circuitry are configured to carryout a method according to any of claims 22-27.

36. A second network node, adapted to carryout a method according to any of claims 21-27.

Images