Method and apparatus for handling secondary cell groups in execution of layer 1 / layer 2 triggered mobility cell handover

Abstract

Embodiments described herein relate to methods and apparatus for enabling performance of actions related to a first secondary cell group upon performance of Layer 1 (L1) / Layer 2L2 triggered mobility cell handover. A method performed by a user equipment communicating with a source node in a primary cell group (MCG) includes performing a Layer 1 / Layer 2 Inter Cell Mobility (LTM) cell handover procedure from the source node to a target node; and performing one or more actions related to the first secondary cell group after or during performing the LTM cell handover procedure.

Description

Technical Field

[0001] The embodiments described herein relate to methods and apparatuses for enabling the execution of actions related to a first secondary cell group during the execution of a layer 1 (L1) / layer 2 (L2)-triggered mobility cell handover. Background Art

[0002] L1 / L2-Triggered Mobility

[0003] In 3GPP Release 18, a work item called Further NR Mobility Enhancements has been agreed. This work item includes the technical area of L1 / L2-based inter-cell mobility. According to the work item description WID RP-222332, “Further New Radio (NR) Mobility Enhancements”, MediaTek, 3GPP TSG RAN Meeting #97-e, Electronic Meeting, 12-16 September 2022, when a user equipment (UE) moves from the coverage area of one cell to another cell, at some point a serving cell change needs to be performed. The current serving cell change is triggered by layer 3 (L3) measurements and completed by reconfiguration triggered by radio resource control (RRC) signaling, with synchronization of changes to the primary cell (PCell) and primary secondary cell (PSCell) and release / addition of secondary cells (SCells) when applicable. All cases involve a complete L2 (and L1) reset, resulting in longer latency, greater overhead, and longer interruption times compared to beam switching mobility. The goal of L1 / L2-based inter-cell mobility is to enable serving cell changes via L1 / L2 signaling in order to reduce latency, overhead, and interruption times.

[0004] In WID RP-222332, the following is included as an objective of the work:

[0020] In 3GPP, discussions have started on solutions for L1 / L2-based inter-cell mobility (sometimes also referred to as LTM, L1 / L2-triggered mobility, or lower layer-triggered mobility).

[0021] The basic principle of L1 / L2-triggered mobility is that the UE is pre-configured by the network with the RRC configuration of each LTM candidate target cell, sometimes also referred to as the LTM candidate target cell configuration. Such an LTM candidate target cell configuration can be an RRCReconfiguration message or one or more information elements (IEs) / fields / parameters (such as CellGroupConfig). The UE performs measurements on these candidate LTM candidate target cells and sends the corresponding measurement reports to the network. Then, the network triggers the execution of an LTM cell handover in the UE by sending a lower-layer signal (such as a media access control (MAC) control element (CE) or downlink control information (DCI)) to the UE, and the UE then connects to the target cell and switches to the configuration of the LTM candidate target cell.

[0022] In the 3GPP RAN2#119-e and RAN2#119bis-e meetings, there are multiple protocols regarding L1 / L2-triggered mobility, and among them are the following: · The RAN is to consider the preparation of the target cell configuration that can be dynamically switched without a full configuration. · R2 assumption: Rel-18 L1 / L2 mobility includes non-carrier aggregation (CA) (only PCell) and CA scenarios (PCell and SCell). This includes the following cases: a) The target PCell / target (s) SCell is not the current serving cell (CA → CA scenario with PCell change) b) FFS, the target PCell is the current SCell c) FFS, the target SCell is the current PCell. · The DC scenario is FFS (e.g., PSCell mobility can be an easy-to-implement target FFS). · Before the L1 / L2 dynamic handover is triggered, the L1 / L2 inter-cell mobility candidate (target) configuration is received within an RRC message. · RAN2 continues to discuss the RRC model by focusing on Model 1 and Model 2 and Phase 3 details. a. Model 1: One RRCReconfiguration message (or FFS RRCReconfiguration IE) for each candidate target configuration b. Model 2: One CellGroupConfig IE (FFS additional IE) for each candidate target configuration · RAN2 uses "LTM" as the term for L1 / L2-triggered mobility. · The term "cell handover" is used for the process of triggering a cell change via the LTM feature · For the case of cell handover between L1 / L2 mobility candidates without RRC reconfiguration in between, the term "subsequent" LTM is used. · RAN2 assumes that sequential L1L2 cell changes between candidates can be supported without RRC reconfiguration. · RAN2 assumes that the candidate cell configuration can only be modified / released by the network (FFS whether some optimizations should be applied later for release, e.g.). · For L1L2 mobility, the candidate configuration to be supported is the difference configuration on top of the reference configuration. FFS if the reference configuration is a separate reference configuration or, e.g., the current configuration. · For L1L2 mobility, the target Pcell / SCell can be the current SCell / PCell, i.e., the current SCell / PCell can be configured as a candidate. · RAN2 assumes that the L1 / 2 mobility trigger information is transmitted in the MAC CE, FFS if the MAC CE or DCI is used for the actual trigger. · RAN2 assumes that the MAC CE triggered for L1 / 2 mobility contains at least the candidate configuration index. · L1L2-based mobility supports the following CA scenarios: PCell change without SCell change PCell change with SCell change · NR-DC scenarios in L1L2-based mobility are supported, at least for PSCell changes without MN participation (i.e., within the SN).

[0023] At the RAN3#117-e and RAN3#117bis-e meetings, there were multiple protocols regarding L1 / L2-based inter-cell mobility, and among them were the following:

[0025] - For L1 / L2 mobility, both the in-DU and inter-DU within CU scenarios are supported.

[0026] - RAN3 will target a single solution for network signaling on L1 / L2-based inter-cell mobility to support all agreed scenarios. The details of the solution are FFS.

[0027] - The gNB-CU initiates the L1 / L2 mobility configuration process.

[0028] - The configuration of the (multiple) candidate target cells for L1 / L2 mobility is initiated by the gNB-CU.

[0029] - WA: It is assumed in RAN3 that the UE sends an L1 measurement report to the gNB-DU, and the gNB-DU triggers UE mobility to a target candidate cell. All details are subject to RAN1 and RAN2 discussions.

[0030] - During L1 / L2 handover configuration, the gNB-CU sends the proposed (multiple) candidate cells to the gNB-DU in the UE context modification request procedure, FFS in one message or multiple messages.

[0031] - The gNB-DU can accept the target cell for L1 / L2 handover and respond to the gNB-CU with the access control result in the (multiple) UE context modification response message. The gNB-DU can accept all or part of the target candidate cells.

[0032] - L1 / L2 handover configuration initiated by the gNB-DU is not allowed.

[0033] - The UE sends a lower layer measurement report to the gNB-DU, and the gNB-DU triggers UE mobility to a target candidate cell.

[0034] - WA: The gNB-DU indicates to the gNB-CU the successful access of the UE to the target cell via an access success message.

[0035] - For inter-DU inter-cell mobility, the UE context establishment procedure is reused for handover configuration.

[0036] 3GPP Dual Connectivity

[0037] In 3GPP Rel-12, Long Term Evolution (LTE) feature dual connectivity (DC) was introduced to enable the UE to be connected in two cell groups, each cell group being controlled by an LTE access node (eNB), which are labeled as the master eNB (MeNB) and the secondary eNB (SeNB). The UE still has only one RRC connection to the network. In 3GPP, the dual connectivity (DC) solution has since evolved and is now also specified for NR as well as between LTE and NR. With the introduction of 5G, the term MR-DC (Multi-Radio Dual Connectivity, also see 3GPP TS37.340) was defined as a general term for all dual connectivity options including at least one NR access node. Using the general term MR-DC, the UE is connected in a master cell group (MCG) controlled by a master node (MN) and a secondary cell group (SCG) controlled by a secondary node (SN).

[0038] In addition, in MR-DC, when dual connectivity is configured for a UE, carrier aggregation can also be used within each of the two cell groups, MCG and SCG. In this case, within the master cell group MCG controlled by the master node (MN), the UE can use one PCell and one or more SCell. And within the secondary cell group SCG controlled by the secondary node (SN), the UE can use one primary SCell (PSCell, also referred to as the primary SCG cell in NR) and one or more SCell. Figure 1 FIG. shows dual connectivity combined with carrier aggregation in MR-DC. In NR, the master cell of the master cell group or the secondary cell group is sometimes also referred to as a special cell (SpCell). Thus, the SpCell in MCG is the PCell, and the SpCell in SCG is the PSCell.

[0039] There are different ways to deploy a 5G network with or without interworking with LTE (also known as E-UTRA) and the evolved packet core (EPC). These different ways of deploying 5G are also referred to as architecture options. In principle, NR and LTE can be deployed without any interworking, represented by stand-alone (SA) operation of NR, also known as architecture option 2, i.e., the gNB in NR can be connected to the 5G core network (5GC), and the eNB in LTE can be connected to the EPC, without any interconnection between the two, also known as architecture option 1.

[0040] On the other hand, the first supported version of NR uses dual connectivity, denoted as EN-DC (E-UTRAN-NR dual connectivity), also known as architecture option 3, as Figure 2 shown. In such a deployment, dual connectivity between NR and LTE is applied, where the UE is connected to both the LTE radio interface to the LTE access node (LTE Uu in the figure) and the NR radio interface to the NR access node (NR Uu in the figure). In addition, in EN-DC, the LTE access node acts as the master node (referred to as the master eNB, MeNB in this case), controlling the master cell group MCG, and the NR access node acts as the secondary node (sometimes also referred to as the secondary gNB, SgNB in this case), controlling the secondary cell group SCG. The SgNB has a user plane connection S1-U to the core network (EPC). The control plane connection S1-C to the core network (EPC) is alternatively provided by the MeNB. This is also referred to as "non-standalone NR" or simply "NSA NR". Note that in this case, the functions of the NR cells are limited and will be used as boosters and / or diversity branches for connected-mode UEs, but RRC_IDLE UEs cannot camp on these NR cells. In EN-DC, there is no connection to the 5G core network (5GC).

[0041] With the introduction of 5GC, other options can also be valid. As mentioned above, Option 2 supports stand-alone NR deployment where the gNB is connected to the 5GC. Similarly, LTE can also be connected to the 5GC using Option 5 (also known as eLTE, E-UTRA / 5GC, or LTE / 5GC, and the node can be called ng-eNB). In these cases, both NR and LTE are considered part of the NG-RAN (and both ng-eNB and gNB can be called NG-RAN nodes).

[0042] It is worth noting that there are also other variants of dual connectivity between LTE and NR, which have been standardized as part of the NG-RAN connected to the 5GC. Under the umbrella of MR-DC, we have:

[0043] EN-DC (also known as architecture Option 3): LTE is the master node and NR is the secondary node (EPC CN is adopted, as Figure 2 shown)

[0044] NE-DC (also known as architecture Option 4): NR is the master node and LTE is the secondary node (5GC is adopted)

[0045] NGEN-DC (also known as architecture Option 7): LTE is the master node and NR is the secondary node (5GC is adopted)

[0046] NR-DC (variant of architecture Option 2): Dual connectivity where both the master node MN controlling the MCG and the secondary node SN controlling the SCG are NR (5GC is adopted, as Figure 3 shown).

[0047] In NR-DC, as Figure 3 shown, the secondary node (NR SN) is a gNB that provides the NR radio interface NR Uu to the UE and has a user plane connection NG-U to the 5G core network (5GC). The master node (NR MN) is also a gNB that provides the NR radio interface NR Uu to the UE and has a control plane connection NG-C and a user plane connection NG-U to the 5G core network (5GC). Between the MN and the SN, the Xn interface is used.

[0048] Since the migration for these options may vary for different operators, it is possible to deploy multiple options in parallel in the same network. For example, in the same network as an NR base station supporting architecture options 2 and 4, there may be eNB base stations supporting architecture options 3, 5, and 7. Combining the dual-connectivity solution between LTE and NR, it is also possible to support CA (carrier aggregation) in each cell group (i.e., MCG and SCG) and dual-connectivity between nodes on the same RAT (e.g., NR-NR DC). For LTE cells, the result of these different deployments is the coexistence of LTE cells associated with eNBs connected to the EPC, 5GC, or both the EPC and 5GC.

[0049] As mentioned earlier, DC is standardized for both LTE and E-UTRA-NR DC (EN-DC).

[0050] LTE DC and EN-DC are designed differently in terms of which nodes control what. Basically, there are two options:

[0051] A centralized solution (such as LTE-DC),

[0052] A decentralized solution (such as EN-DC).

[0053] Figure 4 Shows an example of a schematic control plane architecture for LTE DC, EN-DC, and NR-DC. The main difference here is that in EN-DC and NR-DC, the secondary node SN has a separate NR RRC entity. This means that the SN can also control the UE, sometimes directly to the UE using the NR radio interface NR Uu, without knowing the MN. However, typically the SN may need to coordinate with the master node MN. The UE has an LTE RRC state in EN-DC and an NR RRC state in NR-DC. Further, in LTE-DC and EN-DC, the control plane interface between the MN and the SN is X2-C. In LTE-DC, RRC decisions can be received from the MN (the MN uses the LTE radio interface LTE Uu to the UE). However, note that the SN can still decide the configuration of the SN because only the SN itself knows what type of resources or capabilities it has. In addition, in LTE-DC, the UE has an LTE RRC state. In addition, in NR-DC, the control plane interface between the MN and the SN is Xn-C.

[0054] Figure 4 Shows the control plane architecture for dual-connectivity in LTE DC, EN-DC, and NR-DC.

[0055] For EN-DC and NR-DC, the main changes compared to LTE DC are:

[0056] - Introduce a split data radio bearer (DRB) from the SN (referred to as the SN-terminated split DRB)

[0057] - Introduce a split signaling radio bearer (SRB) for RRC

[0058] - Introduce a direct SRB from the SN (also referred to as the SCG SRB or SRB3)

[0059] Figure 5 The user plane protocol architecture in MR-DC (EN-DC) with EPC is shown from the network perspective. Bearers can be classified into bearer types. Each bearer type is characterized by which radio resources are involved. For MCG bearers, only MCG radio resources and the radio link control (RLC) + MAC layer entities for MCG are involved. For SCG bearers, only SCG radio resources and the RLC + MAC layer entities for SCG are involved. For split bearers, both MCG radio resources and SCG radio resources and the RLC + MAC layer entities for both MCG and SCG are involved. In addition, depending on the network node where the bearer is terminated, the bearer can also be classified into MN-terminated bearers and SN-terminated bearers. For MN-terminated bearers, the physical downlink control plane (PDCP) layer entity and the user plane connection to the core network are terminated in the MN. For SN-terminated bearers, the PDCP layer entity and the user plane connection to the core network are terminated in the SN.

[0060] The network can configure the E-UTRA PDCP layer or the NR PDCP layer for MN-terminated MCG bearers, while the NR PDCP layer is always used for all other bearers. In this case, the network can configure E-UTRA PDCP or NR PDCP for MN-terminated MCG DRBs, while NR PDCP is always used for all other DRBs.

[0061] Figure 5 The network-side protocol termination options for MCG, SCG, and split DRBs in MR-DC (EN-DC) with EPC are shown.

[0062] Figure 5The user plane protocol architecture in MR-DC (NGEN-DC, NE-DC, and NR-DC) with 5GC is shown from a network perspective. In MR-DC with 5GC, NR PDCP is always used for all DRB types. In NGEN-DC, E-UTRA RLC / MAC is used in the MN, while NR RLC / MAC is used in the SN. In NE-DC, NR RLC / MAC is used in the MN, while E-UTRA RLC / MAC is used in the SN. In NR-DC, NR RLC / MAC is used in both the MN and the SN.

[0063] Figure 6 The network-side protocol termination options for MCG, SCG, and split DRBs in MR-DC (NGEN-DC, NE-DC, and NR-DC) with 5GC are shown.

[0064] EN-DC Capability Coordination

[0065] In EN-DC, the configuration restriction information in the inter-node message signaling is used to perform the capability coordination in terms of the UE-supported band combination (BC).

[0066] After selecting the BC for the MCG, the MN signals the allowed BC for the SCG to the SN in the ConfigRestrictInfoSCG of the CG-ConfigInfo. ConfigRestrictInfoSCG contains a list of BCs and the corresponding FeatureSet from which the SN can select, see the ASN.1 fragment of the CG-ConfigInfo from below.

[0067] ConfigRestrictInfoSCG::= SEQUENCE{

[0068] allowedBC-ListMRDC BandCombinationInfoList OPTIONAL,

[0069] powerCoordination-FR1 SEQUENCE{

[0070] p-maxNR-FR1 P-Max OPTIONAL,

[0071] p-maxEUTRA P-Max OPTIONAL,

[0072] p-maxUE-FR1 P-Max OPTIONAL

[0073] }OPTIONAL,

[0074] servCellIndexRangeSCG SEQUENCE {

[0075] lowBound ServCellIndex,

[0076] upBound ServCellIndex

[0077] } OPTIONAL, -- Cond SN-Addition

[0078] maxMeasFreqsSCG-NR INTEGER(1..maxMeasFreqsMN) OPTIONAL,

[0079] maxMeasIdentitiesSCG-NR INTEGER(1..maxMeasIdentitiesMN) OPTIONAL, ...

[0081] }

[0083] BandCombinationInfoList ::= SEQUENCE(SIZE(1..maxBandComb)) OF BandCombinationInfo

[0085] BandCombinationInfo ::= SEQUENCE {

[0086] bandCombinationIndex BandCombinationIndex,

[0087] allowedFeatureSetsList SEQUENCE(SIZE(1..maxFeatureSetsPerBand)) OF FeatureSetEntryIndex

[0088] }

[0090] FeatureSetEntryIndex ::= INTEGER(1..maxFeatureSetsPerBand)

[0091] Conversely, once the SN has selected an NR band for the SCG configuration, it can use the selectedBandCombinationNR of CG-Config to notify the MN of the selected SCG band combination, as shown in the following ASN.1 fragment.

[0092] CG-Config-IEs::= SEQUENCE{

[0093] scg-CellGroupConfig OCTET STRING(CONTAINING RRCReconfiguration) OPTIONAL,

[0094] scg-RB-Config OCTET STRING(CONTAINING RadioBearerConfig) OPTIONAL,

[0095] configRestrictModReq ConfigRestrictModReqSCG OPTIONAL,

[0096] drx-InfoSCG DRX-Info OPTIONAL,

[0097] candidateCellInfoListSN OCTET STRING(CONTAINING MeasResultList2NR) OPTIONAL,

[0098] measConfigSN MeasConfigSN OPTIONAL,

[0099] selectedBandCombinationNR BandCombinationInfoSN OPTIONAL,

[0100] fr-InfoListSCG FR-InfoList OPTIONAL,

[0101] candidateServingFreqListNR CandidateServingFreqListNR OPTIONAL,

[0102] nonCriticalExtension SEQUENCE{} OPTIONAL

[0103] } Summary of the Invention

[0104] There are certain challenges. At the last RAN2#119-bis-e meeting, the following agreements were reached regarding the use of L1 / L2-triggered mobility (LTM) with dual connectivity (DC): Support the NR-DC scenario in L1L2-based mobility, at least for PSCell changes without MN participation (i.e., within the SN).

[0105] This protocol means that LTM on the SCG is independent of LTM on the MCG, but the same conclusion may not hold in the other way. Also, for the SCG, only the case of LTM within the SN is supported at this time, and the case of not involving the MN is not involved in the process.

[0106] However, the NR-DC scenario is excluded, and thus a key aspect to be addressed is how to handle the SCG when LTM is executed within the MCG. Generally, the SCG is added upon request from the MCG, and the configuration of the SCG also depends on certain restrictions signaled by the MCG (via the X2 / Xn interface) to the SCG. The restrictions are to ensure that the UE capabilities are not exceeded by the combined MCG and SCG configurations, as explained in the above Background section.

[0107] At this time, the 3GPP assumption is that the SCG is not affected by LTM on the MCG. However, the problem is that if changes are made to the MCG during an LTM cell handover, such as adding an SCell, then in order to avoid exceeding the UE capabilities, the SCG may need to be released. In fact, when performing the LTM cell handover process within the MCG, it is still unclear whether the SCG should be immediately configured, configured but kept in the deactivated state, configured with the active state, or not configured at all (meaning it will be configured at a later moment). For example, it is possible that due to capability limitations in the UE, if there are changes in the MCG configuration, such as during an inter-frequency handover or when an SCell is added, the UE may not be able to support the SCG configured before the LTM cell handover. In addition, it is unclear whether the SCG can be added by performing LTM within the MCG.

[0108] Certain aspects and embodiments of the present disclosure can provide solutions to these or other challenges.

[0109] To address the above challenges, the embodiments described herein propose methods for a user equipment (UE) to handle (e.g., by releasing, suspending, adding, modifying, deactivating, activating, resuming) at least a secondary cell group (SCG) when performing an LTM cell handover process from a source node to a target node for a master cell group (MCG). The SCG can be part of the UE configuration before the LTM cell change, or can be part of the LTM candidate target configuration.

[0110] In one method, the UE receives an indication to handle (e.g., by releasing, suspending, adding, modifying, deactivating, activating, resuming) at least one SCG when performing an LTM cell handover procedure within the MCG from a network node such as a source network node, a target network node, or a third network node.

[0111] In the method, the indication is included in lower layer signaling that indicates to the UE an LTM cell handover procedure at the MCG received from the source network node. In the method, the indication is included in lower layer signaling received from the target network node. In the method, the indication is included in an RRC message including an LTM candidate target cell, where the indication is not within the LTM candidate target cell but is associated with it (e.g., included in the same IE) such that the UE knows which candidate configurations will be modified and which candidate configurations will not be modified. In the method, the indication is included to avoid a UE capability conflict in the UE between the MCG and the SCG due to changes in the MCG performed during the LTM cell handover.

[0112] In the method, the UE sends an indication to a network node such as a source network node, a target network node, or a third network node regarding which SCG has been configured as part of the LTM candidate target cell configuration during the execution of the LTM cell handover procedure within the MCG. In the method, the indication is included in lower layer signaling sent to the target network node.

[0113] The embodiments described herein also present a method for a source network node such as a source gNB / eNB acting as a master node (MN) to provide a master cell group (MCG) to the UE to handle (e.g., by releasing, suspending, adding, modifying, deactivating, activating, resuming) at least a secondary cell group (SCG). When performing an LTM cell handover procedure within the MCG, the SCG can be part of the UE configuration before the LTM cell change or can be part of the LTM candidate target configuration. The LTM cell handover procedure can be within the source node or from the source node to the target node.

[0114] In the method, during the execution of the LTM cell handover procedure within the MCG, the source network node determines to handle (e.g., by releasing, suspending, adding, modifying, deactivating, activating, resuming) the SCG.

[0115] In a method, during the execution of an LTM cell handover procedure within the MCG, a source network node sends an indication to the UE to handle (e.g., by releasing, suspending, adding, modifying, deactivating, activating, resuming) the SCG, which is part of the UE configuration before the execution of the LTM cell handover or part of the LTM candidate target cell configuration. In the method, the indication is included in the lower layer signaling indicating the LTM cell handover procedure within the MCG to the UE. In the method, the indication has been included in the LTM candidate target cell configuration or the release configuration of the SCG sent to the UE before the execution of the LTM cell handover procedure within the MCG. In the method, the indication is included in the lower layer signaling indicating the configuration or release of the SCG, but is different from the lower layer signaling indicating the execution of the LTM cell handover procedure within the MCG to the UE.

[0116] In a method, during the execution of an LTM cell handover procedure within the MCG, a source network node sends a request to a third network node on whether to handle (e.g., by releasing, suspending, adding, modifying, deactivating, activating, resuming) the SCG.

[0117] In a method, during the execution of an LTM cell handover procedure within the MCG, a source network node sends a request to a target network node on whether to handle (e.g., by releasing, suspending, adding, modifying, deactivating, activating, resuming) the SCG.

[0118] In a method, a source network node receives from a third network node an indication to handle (e.g., by releasing, suspending, adding, modifying, deactivating, activating, resuming) the SCG during the execution of the LTM cell handover procedure within the MCG.

[0119] In a method, a source network node receives from a target network node an indication to handle (e.g., by releasing, suspending, adding, modifying, deactivating, activating, resuming) the SCG during the execution of the LTM cell handover procedure within the MCG. In the method, when the LTM cell handover procedure within the MCG is executed, the source network node receives from the UE an indication of which SCG has been configured as part of the LTM candidate target cell configuration.

[0120] Embodiments described herein also present a method for a target network node (such as a target gNB / eNB) acting as a master node (MN) to provide a master cell group (MCG) to a UE to handle (e.g., by releasing, suspending, adding, modifying, deactivating, activating, resuming) at least a secondary cell group (SCG). When executing an LTM cell handover procedure within the MCG, the SCG can be part of the UE configuration before the LTM cell change, or can be part of the LTM candidate target configuration. The LTM cell handover procedure can be within the source node or from the source node to the target node.

[0121] In the method, during the execution of the LTM cell handover procedure within the MCG, the target network node determines to handle (e.g., by releasing, pausing, adding, modifying, deactivating, activating, resuming) the SCG.

[0122] In the method, after the execution of the LTM cell handover procedure within the MCG, the target network node sends an indication to the UE to handle (e.g., by releasing, pausing, adding, modifying, deactivating, activating, resuming) the SCG. In the method, the indication is included in the lower layer signaling indicating the UE configuration of the SCG.

[0123] In the method, the target network node receives a request from a third network node to handle (e.g., by releasing, pausing, adding, modifying, deactivating, activating, resuming) the SCG during the execution of the LTM cell handover procedure within the MCG.

[0124] In the method, the target network node receives a request from the source network node to handle (e.g., by releasing, pausing, adding, modifying, deactivating, activating, resuming) the SCG during the execution of the LTM cell handover procedure within the MCG.

[0125] In the method, during the execution of the LTM cell handover procedure within the MCG, the target network node sends an indication to the third network node regarding whether to handle (e.g., by releasing, pausing, adding, modifying, deactivating, activating, resuming) the SCG.

[0126] In the method, during the execution of the LTM cell handover procedure within the MCG, the target network node sends an indication to the source network node regarding whether to handle (e.g., by releasing, pausing, adding, modifying, deactivating, activating, resuming) the SCG.

[0127] In the method, after the execution of the LTM cell handover procedure within the MCG, the target network node receives an indication from the UE regarding which SCG has been configured as part of the LTM candidate target cell configuration.

[0128] The embodiments described herein also present a method for a third network node (such as a gNB / eNB) acting as a secondary node (SN) to provide a secondary cell group (SCG) to a UE to handle (e.g., by releasing, pausing, adding, modifying, deactivating, activating, resuming) at least the secondary cell group (SCG). When performing the LTM cell handover procedure within the MCG, the SCG can be part of the UE configuration before the LTM cell change, or can be part of the LTM candidate target configuration. The LTM cell handover procedure can be within the source node or from the source node to the target node.

[0129] In the method, during the execution of the LTM cell handover procedure within the MCG, a third network node determines to handle (e.g., by releasing, pausing, adding, modifying, deactivating, activating, resuming) the SCG.

[0130] In the method, a third network node sends an indication to the UE to handle (e.g., by releasing, pausing, adding, modifying, deactivating, activating, resuming) the SCG. In the method, the indication is included in the configuration of the LTM candidate target cell.

[0131] In the method, a third network node sends an indication to the source network node to handle (e.g., by releasing, pausing, adding, modifying, deactivating, activating, resuming) the SCG.

[0132] In the method, a third network node sends an indication to the target network node to handle (e.g., by releasing, pausing, adding, modifying, deactivating, activating, resuming) the SCG.

[0133] In the method, a third network node receives a request from the source network node to handle (e.g., by releasing, pausing, adding, modifying, deactivating, activating, resuming) the SCG.

[0134] In the method, a third network node receives a request from the target network node to handle (e.g., by releasing, pausing, adding, modifying, deactivating, activating, resuming) the SCG.

[0135] In the method, after the execution of the LTM cell handover procedure within the MCG, a third network node receives from the UE an indication of which SCG has been configured as part of the LTM candidate target cell configuration.

[0136] According to some embodiments, there is provided a method performed by a user equipment communicating with a source node in a primary cell group MCG. The method includes performing a layer 1 / layer 2 based inter-cell mobility LTM cell handover procedure from the source node to a target node, and performing one or more actions related to a first secondary cell group after or during the execution of the LTM cell handover procedure.

[0137] According to some embodiments, there is provided a method performed by a source node that provides a primary cell group MCG to a user equipment. The method includes performing, for the user equipment, a layer 1 / layer 2 based inter-cell mobility LTM cell handover procedure from the source node to a target node; and obtaining one or more actions related to a first secondary cell group during the execution of the LTM cell handover procedure.

[0138] According to some embodiments, a method performed by a target node is provided for providing a master cell group (MCG) to a user equipment. The method includes: performing, for the user equipment, a layer 1 / layer 2 based inter-cell mobility (LTM) cell handover process from a source node to a target node in the MCG; and obtaining, after or during performing the LTM cell handover process, one or more actions related to a first secondary cell group.

[0139] According to some embodiments, a method performed by a third network node is provided for providing a first secondary cell group to a user equipment. The method includes: obtaining, before, during, or after performing a layer 1 / layer 2 based inter-cell mobility (LTM) cell handover process for the user equipment from a source node to a target node for a master cell group, one or more actions related to the first secondary cell group.

[0140] According to some embodiments, a user equipment (UE) for communicating with a source node in a master cell group is provided. The UE includes processing circuitry and a memory including instructions executable by the processing circuitry, whereby the UE is operable to: perform a layer 1 / layer 2 based inter-cell mobility (LTM) cell handover process from the source node to a target node, and perform, after or during performing the LTM cell handover process, one or more actions related to a first secondary cell group.

[0141] According to some embodiments, a source node for providing a master cell group (MCG) to a user equipment is provided. The source node includes processing circuitry and a memory including instructions executable by the processing circuitry, whereby the source node is operable to: perform, for the user equipment, a layer 1 / layer 2 based inter-cell mobility (LTM) cell handover process from the source node to a target node; and obtain, during performing the LTM cell handover process, one or more actions related to a first secondary cell group.

[0142] According to some embodiments, a target node for providing a master cell group (MCG) to a user equipment is provided. The target node includes processing circuitry and a memory including instructions executable by the processing circuitry, whereby the target node is operable to: perform, for the user equipment, a layer 1 / layer 2 based inter-cell mobility (LTM) cell handover process from the source node to the target node in the MCG, and obtain, after or during performing the LTM cell handover process, one or more actions related to a first secondary cell group.

[0143] According to some embodiments, there is provided a third network node for providing a first secondary cell group to a user equipment. The third network node includes processing circuitry and a memory including instructions executable by the processing circuitry, whereby the third network node is operable to: obtain one or more actions related to the first secondary cell group before, during, or after performing a layer 1 / layer 2 based inter-cell mobility LTM cell handover procedure for the user equipment from a source node to a target node for a master cell group.

[0144] According to some embodiments, there is provided a computer program including instructions that, when executed on at least one processor, cause the at least one processor to perform any of the above methods.

[0145] According to some embodiments, there is provided a computer-readable medium including instructions that, when executed on at least one processor, cause the at least one processor to perform any of the above methods.

[0146] According to some embodiments, there is provided a computer program product including a non-transitory computer-readable medium having stored thereon the computer program as described above.

[0147] Certain embodiments may provide one or more of the following technical advantages. The embodiments described herein allow for the rapid setup and handling of an SCG during an LTM cell handover procedure in an MCG, thereby increasing the overall capacity and throughput of the system. The embodiments described herein also allow for the rapid setup of an SCG and the handling of specific use cases that require low latency and high data rates. BRIEF DESCRIPTION OF THE DRAWINGS

[0148] To better understand embodiments of the present disclosure and to show how they may be effected, reference will now be made, by way of example only, to the accompanying drawings, in which:

[0149] Figure 1 shows dual connectivity combined with carrier aggregation in MR-DC;

[0150] Figure 2 shows EN-DC;

[0151] Figure 3 shows NR-DC;

[0152] Figure 4 shows how a schematic control plane architecture looks for LTE DC, EN-DC, and NR-DC;

[0153] Figure 5 shows a user plane protocol architecture in MR-DC (EN-DC) with an EPC from a network perspective;

[0154] Figure 6Shows the user plane protocol architecture in MR-DC (NGEN-DC, NE-DC, and NR-DC) with 5GC from a network perspective;

[0155] Figure 7 Shows an example of the overall architecture (with both NG-RAN and 5GC), where NG-RAN is split between a CU and a DU connected via the F1 interface

[0156] Figure 8 Is a flowchart showing a method according to some embodiments;

[0157] Figure 9 Is a flowchart showing a method according to some embodiments;

[0158] Figure 10 Is a flowchart showing a method according to some embodiments;

[0159] Figure 11 Is a flowchart showing a method according to some embodiments;

[0160] Figure 12 Is an example signaling diagram;

[0161] Figure 13 Is an example signaling diagram;

[0162] Figure 14 Is an example signaling diagram;

[0163] Figure 15 Shows an example of a communication system according to some embodiments;

[0164] Figure 16 Shows a UE according to some embodiments;

[0165] Figure 17 Shows a network node according to some embodiments;

[0166] Figure 18 Is a block diagram of a host;

[0167] Figure 19 Is a block diagram of a virtualization environment in which functions implemented by some embodiments can be virtualized; and

[0168] Figure 20 Shows a communication diagram of a host communicating with a UE via a network node through a partial wireless connection according to some embodiments. Detailed Description

[0169] Some embodiments contemplated herein will now be described more fully with reference to the accompanying drawings. The embodiments are provided by way of example to convey the scope of the subject matter to those skilled in the art.

[0170] Figure 7 shows an example of an overall network architecture (with both NG-RAN and 5GC), where the NG-RAN is divided into a Central Unit (CU) and a Distributed Unit (DU) connected via the F1 interface. Specifically, Figure 7 shows the overall architecture of the CU and DU disclosed in the embodiments described herein as a Radio Access Network (RAN). The document uses the following example: a RAN corresponding to the Next Generation RAN (NG-RAN), which may be referred to as 5G RAN. However, the method is applicable to any RAN, such as a Sixth Generation (6G) RAN architecture, which may follow a similar division or a different functional division.

[0171] The RAN (e.g., NG-RAN) includes a set of RAN nodes (e.g., gNB, 6G gNodeB) connected to the core network (e.g., 5GC, 6G core network) via a RAN / CN interface (e.g., NG interface, S1 interface, 6G NG 1). In the case of NG-RAN, this may include one or more ng-eNBs, where an ng-eNB may consist of an ng-eNB-CU and one or more ng-eNB-DUs. A gNB may consist of a gNB-CU and one or more gNB-DUs. The gNB-CU and gNB-DU are connected via the F1 interface. The gNB-DU may be connected to multiple gNB-CUs through appropriate implementation.

[0172] NG, Xn, and F1 are logical interfaces. Also, in the case of NG-RAN, the NG and Xn-C interfaces for the gNB consisting of the gNB-CU and gNB-DU terminate in the gNB-CU. For EN-DC, the S1-U and X2-C interfaces for the gNB consisting of the gNB-CU and gNB-DU terminate in the gNB-CU. Thus, when the method refers to the CU, the method includes the (multiple) actions performed by any entity included within the CU (e.g., CU-CP, gNB-CU-CP).

[0173] In some examples, there may be an interface directly between different gNB-DUs. Signaling sent from one gNB-DU to another gNB-DU, e.g., signaling from / to a source gNB-DU to / from a target gNB-DU, may then be sent directly between the gNB-DUs without going through the gNB-CU. In cases throughout this disclosure where signaling is written as going from one DU (e.g., gNB-DU) to another DU (e.g., gNB-DU) via the CU (e.g., gNB-CU), it should be understood that the same signaling may also be sent directly from one DU (e.g., gNB-DU) to another DU (e.g., gNB-DU).

[0174] In this document, the term "L1 / L2-based inter-cell mobility" as used in the work item descriptions in 3GPP can be used interchangeably with the terms L1 / L2-triggered mobility (LTM), lower layer mobility (LLM), L1 / L2 mobility, L1 mobility, L1-based mobility, L1 / L2-centric inter-cell mobility, or L1 / L2 inter-cell mobility. The basic principle is that the UE receives lower layer signaling from the network, which indicates to the UE a change (or handover or activation) of its serving cell (e.g., a change of the PCell from a source to a target PCell), where the lower layer signaling is a message / signaling of a lower layer protocol, which can be referred to as an L1 / L2 inter-cell mobility execution command or a cell handover command / message. A change of the serving cell (e.g., a change of the PCell) can also result in a change of the (multiple) Scells for the same cell group, e.g., in the case where the command triggers the UE to change to another cell group configuration of the same type (e.g., another MCG configuration).

[0175] Compared with the RRC protocol, the lower layer protocol refers to the lower layer protocols in the air interface protocol stack. For example, the media access control (MAC) is considered a lower layer protocol because it is "below" in the air interface protocol stack, and in this case, the lower layer signaling / message can correspond to a MAC control element (MAC CE). Another example of a lower layer protocol is layer 1 (or the physical layer L1), and in this case, the lower layer signaling / message can correspond to downlink control information (DCI). The signaling information in the protocol layer below RRC reduces the processing time and thus reduces the interruption time during mobility; in addition, it can also increase mobility robustness because the network can respond to faster changes in the channel conditions. Another related aspect in L1 / L2 inter-cell mobility is that in a multi-beam scenario, a cell can be associated with multiple synchronization signal blocks (SSBs), and during a half-frame, different SSBs can be transmitted in different spatial directions (i.e., using different beams, across the coverage area of the cell). Similar reasoning can apply to CSI-RS resources, which can also be transmitted in different spatial directions. Therefore, in L1 / L2 inter-cell mobility, the reception of the lower layer signaling indicates to the UE a change from one beam in the serving cell to another beam in an adjacent cell (which is a configured candidate cell), and by this change, the serving cell (cell handover for LTM).

[0176] The phrase "low-layer signaling for indicating to the UE the LTM cell handover procedure" is a message / signal / indication sent by the source network node to the UE to provide the UE with the information required for the LTM cell handover procedure. The signaling being "low-layer" means that the signaling is at a layer of the protocol stack below the RRC layer, such as signaling in L1 and / or L2, such as Media Access Control Control Element (MAC CE). When the UE receives the low-layer signaling for indicating the LTM cell handover procedure, the UE starts to perform the LTM cell handover procedure. However, this does not exclude the UE from being able to start performing the LTM cell handover procedure based on other triggers or events.

[0177] Embodiments of this document relate to the configuration of LTM candidate target cells, and the UE is configured with at least one LTM candidate target cell. This configuration can be an RRC configuration received by the UE when it is configured with inter-DU L1 / L2 inter-cell mobility, such as encapsulated in an RRC reconfiguration message. The configuration of the LTM candidate target cell includes the configuration that the UE needs to start operating accordingly when the UE performs an LTM cell handover procedure to this LTM candidate target cell (e.g., when receiving the low-layer signaling for indicating the LTM cell handover procedure to this LTM candidate target cell), and this LTM candidate target cell becomes the target cell and the current (new) SpCell or SCell or SCG on the serving frequency. The configuration of the LTM candidate target cell includes parameters of the serving cell (or serving cells, such as a cell group), including one or more parameter groups, such as an RRCReconfiguration message, an IECellGroupConfig, or an IE SpCellConfig (or in the case of an SCG, an IE SCellConfig). In one example, the configuration of the LTM candidate target cell may include one or more of the following: i) the PCell configuration of the primary cell group (MCG) and one or more SCell configurations; i) the PSCell configuration of the secondary cell group (SCG) and one or more SCell configurations. When referring to the configuration of the LTM candidate target cell, the terms (LTM) candidate configuration, LTM configuration, (LTM) candidate target cell configuration, (LTM) target candidate (cell) configuration can be used interchangeably.

[0178] The phrase LTM cell handover procedure refers to the process by which the UE changes its cell from the source cell to the target cell using L1 / L2-triggered mobility. In the context of L1 / L2-based inter-cell mobility or L1 / L2-triggered mobility (LTM), the LTM cell handover procedure can also be referred to as dynamic handover, LTM handover, (LTM) cell handover, (LTM) serving cell change, or (LTM) cell change.

[0179] In this document, when another node is added in addition to the master node (MN) or the master cell group (MCG) and this is referred to as a secondary node (SN), the term "processing of the secondary cell group (SCG) or secondary node (SN)" is used. This term can also include actions of creating (generating) and / or releasing (discarding) and / or changing the state of the configuration of the SN / SCG. In one example, the UE configures the SN / SCG according to what is received in the LTM candidate target cell configuration and changes the "state" of the SN / SCG to "active" or "deactivated". Additionally, in general, the term "SN" refers to the entire node that hosts both the lower layers (e.g., PHY, MAC, RLF) and the higher layers (e.g., SDAP, PDCP, RRC). However, for the lower layers, the term "SCG" is also used, so it can be said that "SCG" is a subset of "SN". However, for simplicity, it is assumed here that the terms "SN" and "SCG" can be used interchangeably without loss of any meaning.

[0180] Embodiments in this document also relate to actions "when executing the LTM cell handover procedure (also referred to as cell handover for LTM) within the MCG". However, it should be understood that this can cover any moment when a lower layer mobility command for the in-execution cell handover for LTM is received within the MCG (e.g., a MAC CE indicating the target candidate configuration), such as when receiving, when the UE applies the lower layer command (e.g., as part of an action in the UE), or after the UE performs random access to the target cell (which is a cell belonging to the MN during the LTM cell handover), or before the UE performs random access to the target cell (which is a cell belonging to the MN during the LTM cell handover), or before / after the UE starts monitoring the PDCCH (or generally a control channel) in the target cell (which is a cell belonging to the MN during the LTM cell handover), or before the UE sends the first UL message to the target cell (which is a cell belonging to the MN during the LTM cell handover). Additionally, "when executing the LTM cell handover procedure (also referred to as cell handover for LTM) within the MCG" can be used to indicate that the UE is handing over from a source cell to a target cell, where both the source cell and the target cell belong to the same MN.

[0181] Embodiments of this document relate to "processing the SCG", which can involve the UE performing one or more actions at an existing SCG (if it has been configured with one), or involving the UE performing one or more actions at the SCG that is part of the LTM candidate target cell configuration. What actions the UE can perform can include, for example, "release", "modify", "reconfigure", "add", "hold", "deactivate", "activate", "pause", "resume" of the SCG.

[0182] Figure 8Methods according to certain embodiments are described. Figure 8 The method may be performed by a UE or a wireless device (eg, as described later in Figure 15 and Figure 16 The method may be performed by a UE communicating with a source node in a primary cell group. The method starts at step 802, and performs a layer 1 / layer 2-based inter-cell mobility LTM cell switching procedure from a source node to a target node. In step 804, the method includes performing one or more actions related to a first secondary cell group after or during the execution of the LTM cell switching procedure. It should be understood that the term "executing" herein may be considered equivalent to "performing".

[0183] in other words, Figure 8 The method allows a UE to process (e.g., by performing one or more actions, such as: releasing, suspending, adding, modifying, deactivating, activating, restoring the first SCG) at least a first secondary cell group (SCG) when performing an LTM cell handover procedure within the same primary cell group (MCG). The LTM cell handover procedure may be from a source node to a target node.

[0184] The first SCG may be part of the UE configuration before the LTM cell change, or it may be part of the LTM candidate target configuration. In other words, the first SCG may include part of the UE configuration before the LTM cell switching process, or the first SCG may include part of the LTM candidate target configuration. In some examples, the UE may perform actions related to an SCG configured before the LTM cell switching process and to an SCG that is part of the LTM candidate target configuration after the LTM cell switching process.

[0185] Figure 8 The method may include the UE receiving an indication of one or more actions regarding the first SCG from a source node, a target node, or a third network node (where the third network node may be configured to provide the first SCG). In other words, the UE may receive an indication from a network node (such as a source network node, a target network node, or a third network node) to process at least the first SCG (e.g., by releasing, suspending, adding, modifying, deactivating, activating, resuming) during execution of an LTM cell handover procedure from the source node to the target node within the MCG.

[0186] However, in some examples, the UE determines whether to release, suspend, add, modify, deactivate, activate or resume at least the first SCG when the LTM cell switching process within the MCG is performed. In other words, Figure 8 The method may include the UE determining one or more actions.

[0187] One or more actions of step 804 may include one or more of the following:

[0188] Release the first SCG;

[0189] Suspend the first SCG,

[0190] Add the first SCG,

[0191] Reconfigure the first SCG,

[0192] Deactivate the first SCG,

[0193] Activate the first SCG,

[0194] Resume the first SCG; and

[0195] Continue to use the first SCG.

[0196] Specifically, some of these actions can be defined as follows: · Continue to Use the First SCG In this action, the SCG that is part of the LTM candidate cell configuration is the same as the existing SCG (which includes the first SCG in this example) configured at the UE before the LTM cell handover process within the MCG is executed. Alternatively, the LTM candidate cell configuration may include a field indicating that the UE continues to use the first SCG. In this case, when the LTM cell handover process within the MCG is executed, the UE can simply continue to use the first (i.e., current) SCG without modifying any parameters / fields / structures related to the configuration of the first SCG. · Reconfigure the First SCG In this example, the UE reconfigures the existing SCG configured at the UE to the first SCG for the LTM cell handover process (the first SCG in this example) to generate a new SCG for the LTM candidate cell configuration. In other words, before the execution of the LTM cell handover within the MCG, the UE can apply the parameters / fields / structures related to the configuration of the new SCG on top of the existing first SCG configuration used by the UE. In this case, if the UE changes the existing configuration of the SCG by using the new configuration received within the LTM candidate cell configuration when the LTM cell handover process is executed, this reconfiguration can be regarded as a "full configuration". Otherwise, if the UE only changes a subset of the parameters / fields / structures related to those parameters / fields / structures that exist in the new cell received within the LTM candidate cell configuration when the LTM cell handover process is executed, this reconfiguration can be regarded as a "delta configuration". · Activate, Deactivate, Suspend。In this example, the first SCG may include one or both of an existing SCG configured at the UE prior to the LTM cell handover procedure or a new SCG that forms part of the MTW candidate cell configuration. The first SCG configured at the UE and its state are set to "active" or "deactivated" or "paused". This means that the UE will apply the parameters / fields / structures related to the configuration of the first SCG, but will start using the first SCG to perform transmission and reception only after the state of the first SCG is changed to "active" after the LTM cell handover procedure within the MCG. After the LTM cell handover procedure is performed within the MCG, the state of the SCG may be changed to "active" by the target network or a third node (e.g., SN). Otherwise, setting the state of the first SCG to "active" or "deactivated" or "paused" may be indicated (within the same lower layer signaling in a different one) together with the lower layer signaling used to perform the LTM cell handover procedure within the MCG. · Release the First SCG 。The first SCG that is part of the LTM candidate cell configuration is indicated as not being used or released by the UE. This means that the UE will ignore the parameters / fields / structures related to the configuration of the first SCG received prior to performing the LTM cell handover procedure within the LTM candidate target cell configuration. This also means that if the UE has configured an existing SCG (and is using it), the UE will simply release the existing SCG after performing the LTM cell handover procedure and retain only the new MCG. Setting the state of the first SCG to "active" or "deactivated" or "paused" may be indicated (within the same lower layer signaling in a different one) together with the lower layer signaling used to perform the LTM cell handover procedure within the MCG.

[0197] In some examples, the state of the SCG (e.g., "active" or "deactivated") is based on at least one of the following signaling options: · In one embodiment, the setting of the "state" of the SCG is based on the RRC configuration received by the UE for LTM. For example, the step of receiving an indication of one or more actions may include receiving radio resource control configuration o In one option, the state is set to "active" or "deactivated" or "paused" or "non-valid" or "invalid" or "released". For example, when a UE with MCG A is configured with LTM candidate MCG B, and together with MCG B, the UE is also configured with SCG A, the UE is instructed that in the case where the UE moves from MCG A to MCG B, the state of SCG A should be set to "active". In another example, when a UE with MCG A and SCG A is configured with LTM candidate MCG B, and together with MCG B, the UE is also configured with SCG B, the UE is instructed that in the case where the UE moves from MCG A to MCG B, the state of SCG A should be set to "released", and the state of SCG B should be set to "active". · In one embodiment, the setting of the "state" of an SCG within the LTM candidate target cell configuration or within a part of the UE configuration before an LTM cell handover is based on lower layer signaling that the UE receives to indicate the execution of LTM (LTM cell handover) within the MCG. For example, a MAC CE for the LTM cell handover or another MAC CE concatenated therewith. It will be understood that such one or more actions may include activating, deactivating, releasing, or pausing one of the first SCGs. An indication of one or more actions may be received in the lower layer signaling, wherein the lower layer signaling further requests the execution of the LTM cell handover procedure. · In one embodiment, the setting of the "state" for an SCG within the LTM candidate target cell configuration is based on measurements performed by the UE. For example, method 8 may include determining one or more actions based on measurements performed by the UE. o In one option, the UE may perform measurements on an SCG that is part of the LTM candidate target cell configuration before receiving the lower layer signaling to indicate the execution of the LTM cell handover procedure. In particular, the UE may perform such measurements because it is configured to do so within the received LTM candidate target cell configuration, or may decide to perform such measurements autonomously, or may be configured to perform such measurements by a third node. The measurements performed by the UE may be L1 measurements or L3 measurements, and this depends on the UE implementation or network configuration. o In one option, the UE may perform measurements on an SCG that is part of the LTM candidate target cell configuration and report such measurements to the network before receiving the lower layer signaling to indicate the execution of the LTM cell handover procedure. Once the measurements are performed, the UE reports such measurements to the source network node or a third network node before receiving the lower layer signaling for the execution of the LTM cell handover procedure. · In some embodiments, the step of receiving an indication of one or more actions related to a first SCG from a source node, a target node, or a third network node includes: receiving an indication of one or more actions in lower layer signaling. The indication may be included in lower layer signaling received different from the E lower layer signaling used to indicate the execution of the LTM cell handover procedure. However, in some examples, the lower layer signaling indicating one or more actions also requests the execution of the LTM cell handover procedure. · In one embodiment, setting the “status” for the SCG within the LTM candidate target cell configuration is based on an indication received from a third network node. o In one option, the third network node may configure the UE to perform SCG measurements on potential LTM candidate SCG target cells, and when the UE reports those measurements, the third network node forwards such measurements to the source network node. As previously described, the UE may receive two distinct lower layer signaling indications from the source network node, one indicating the execution of the LTM cell handover procedure within the MCG and one indicating one or more actions to be performed with respect to the first SCG (e.g., release, suspend, add, modify, deactivate, activate, or resume the first SCG). In one embodiment, the two lower layer signaling indications are sent to the UE in two distinct messages (e.g., two MAC CEs and a MAC PDU). In one embodiment, the two lower layer signaling indications are sent to the UE in the same message (e.g., two MAC CEs within the same MAC PDU).

[0198] In some examples, one of the two distinct lower layer signaling indications received by the UE is sent by the source network node and one is sent by the target network node or a third network node.

[0199] As a default behavior, when performing the LTM cell handover procedure within the MCG, the UE may not configure any new SCG, regardless of whether any SCG is part of the LTM candidate target cell configuration indicated in the lower layer signaling used to perform the LTM cell handover procedure. If the UE has an existing SCG prior to performing the LTM handover procedure, that SCG may be released / deleted. In other words, Figure 8 the method may include the UE not configuring a new SCG at the LTM cell handover procedure and one or more actions including releasing the first SCG, where the first SCG includes the existing SCG.

[0200] As a default behavior, when performing the LTM cell handover procedure within the MCG, the UE may configure the first SCG to have a status set to “deactivated / suspended”, regardless of the status of the first SCG indicated within the LTM candidate target cell configuration (e.g., indicated in the lower layer signaling used to perform the LTM cell handover procedure). In other words,Figure 8 The method may further include deactivating or suspending the first SCG, regardless of the state associated with the first SCG within the LTM candidate target cell configuration used to perform the LTM cell handover procedure.

[0201] After performing the LTM cell handover procedure within the MCG, the UE may send an indication to a network node (such as a source network node, a target network node, or a third network node) regarding which SCGs have been configured as part of the LTM candidate target cell configuration. In other words, Figure 8 the method may include sending an indication of a second SCG that has been configured after performing the LTW cell handover procedure or will be configured during the execution of the LTM procedure. The indication may be sent to the target node, the source node, or the third node. The second SCG may include the first SCG. · In one alternative, the indication is included in the lower layer signaling sent to the target network node. · In one alternative, the indication is included in the lower layer signaling sent to the source network node. · In one alternative, the indication is included in the lower layer signaling sent to the third network node. · In one alternative, the indication is included in the RRC signaling sent to the target network node or the third network node or the source network node.

[0202] As previously described, one or more of the above actions may be applied to an existing SCG (if any) configured at the UE prior to the execution of the LTM cell handover procedure.

[0203] As previously described, one or more of the above actions may be applied to an SCG received within the LTM candidate target cell configuration received by the UE prior to the execution of the LTM cell handover procedure.

[0204] In some examples, the LTM candidate target cell configuration includes only the MCG, only the SCG, or both the MCG and the SCG. In the case where the LTM candidate target cell configuration includes only the MCG or only the SCG, this means that when performing the LTM cell handover procedure, the UE may need to apply two separate LTM candidate target cell configurations, one for the MCG and one for the SCG.

[0205] In some embodiments, the UE receives an RRC reconfiguration including a configuration for LTM from the network (e.g., from a network node operating as an MN): e.g., the message includes at least one LTM candidate cell configuration, such as an embedded RRCReconfiguration (denoted as RRCReconfiguration*) to be applied or switched to when receiving a lower layer command for an LTM cell handover. The embedded RRCReconfiguration* for the target candidate configuration includes a configuration for the master cell group (MCG); when receiving a lower layer command for an LTM cell handover for the MCG, indicating a handover of the PCell (or the MCG in general terms), the UE also performs one or more actions on the configuration, which can be: add (when the UE is not in DC), release (when the UE is in MR-DC, but should not be after a cell handover), modify or simply indicate to keep. Examples of different use cases are as follows: -A) The UE is in DC. During a cell handover for LTM, the UE deletes / releases the MR-DC (e.g., deletes the configured SCG); -B) The UE is in DC. During a cell handover for LTM, the UE remains in the MR-DC without a PSCell change, i.e., keeps the PSCell; -C) The UE is in MR-DC. During a cell handover for LTM, the UE remains in the MR-DC, where the PSCell changes; -D) The UE is not in MR-DC. During a cell handover for LTM, the UE adds an SCG.

[0206] In some embodiments, the UE receives an RRC reconfiguration including a configuration for LTM (e.g., an RRCReconfiguration in MN format, including MCG configuration) from the network (e.g., from a network node operating as the MN): for example, the message includes at least one LTM candidate cell configuration, such as an embedded RRCReconfiguration (denoted as RRCReconfiguration*) to be applied or switched to when receiving a low-layer command for an LTM cell handover. The embedded RRCReconfiguration* for the target candidate configuration includes a configuration for the master cell group (MCG) and a configuration for the secondary cell group (SCG), which is embedded as an SCG RRC reconfiguration (which may be denoted as SN RRCReconfiguration as it is generated by a node operating as the secondary node SN, or RRCReconfiguration**); when receiving a low-layer command for an LTM cell handover for the MCG, indicating a handover of the PCell (or the general term MCG), the UE applies or switches to the configuration in RRCReconfiguration*, and as part of adding and / or modifying and / or releasing the SCG. In other words, the reception of a low-layer cell handover for LTM of the MCG results in one or more actions of adding, releasing, and / or modifying the SCG. In some embodiments, the UE receives an RRC reconfiguration including a configuration for LTM (e.g., an RRCReconfiguration in MN format, including MCG configuration) from the network (e.g., from a network node operating as the MN): for example, the message includes at least one LTM candidate cell configuration, such as an instance of IECellGroupConfig* for the MCG to be applied or switched to when receiving a low-layer command for an LTM cell handover (e.g., as defined in TS 38.331). The embedded CellGroupConfig* for the target candidate configuration includes a configuration for the MCG and a configuration for the secondary cell group (SCG), which is embedded as an SCGCellGroupConfig IE (which may be denoted as SN CellGroupConfig IE as it is generated by a node operating as SN or CellGroupConfig**); when receiving a low-layer command for an LTM cell handover for the MCG, indicating a handover of the PCell (or the general term MCG), the UE applies or switches to the configuration in CellGroupConfig*, and as part of adding and / or modifying and / or releasing the SCG. In other words, the reception of a low-layer cell handover for LTM of the MCG results in one or more actions of adding, releasing, and / or modifying the SCG.

[0207] In some embodiments, the UE receives two messages for LTM in the MCG and LTM in the SCG: - The first RRC reconfiguration from the network (e.g., from a network node operating as the MN), e.g., an RRCReconfiguration in MN format including MCG configuration, includes configuration for LTM for the MCG: e.g., the message includes at least one LTM candidate cell configuration, such as an instance of IE CellGroupConfig* for the MCG (e.g., as defined in TS 38.331). - The second RRC reconfiguration from the network (e.g., from a network node operating as the SN) including configuration for LTM for the SCG, e.g., an RRCReconfiguration in SN format including SCG configuration: e.g., the message includes at least one LTM candidate cell configuration, such as an instance of IE CellGroupConfig** for the SCG to be applied or switched to when a lower layer command for LTM cell handover is received via the SCG MAC entity (e.g., as defined in TS 38.331). - The UE also receives a concatenated MAC PDU that includes i) a first lower layer command for MCG cell handover (first e.g., MAC CE) (including at least a first configuration ID for the MCG candidate cell) and ii) a lower layer command for SCG cell handover (e.g., second MAC CE) (including a second configuration ID as the SCG candidate cell). In other words, the reception of the lower layer cell handover for LTM for the MCG results in one or more actions where the SCG is added, released, and / or modified.

[0208] In a set of embodiments, a UE configured with an SCG receives a command to perform an MCG cell handover for LTM, where no SCG is configured for the UE after the cell handover to the target MCG cell, e.g., the SCG is released as part of the LTM cell handover. Then, as part of the LTM cell handover, the UE stores and / or suspends / deactivates the SCG configuration that it had before the cell handover (when in the source MCG cell). In an alternative, the UE stores and / or suspends / deactivates the SCG configuration based on an indication from the network (e.g., in the lower layer signaling corresponding to the LTM cell handover command, in the LTM candidate target configuration for the target MCG cell, or in the LTM candidate target configuration for the source MCG cell).

[0209] When the UE performs a subsequent MCG cell handover for LTM, it then restores the SCG configuration when it is in the target MCG cell for the LTM cell handover procedure. In one example, the UE restores the SCG configuration to the MCG cell at the MCG cell handover for LTM, where the UE was previously configured with the SCG configuration. In an alternative, the UE restores the SCG configuration based on an indication from the network (e.g., in the lower layer signaling corresponding to the LTM cell handover command, in the LTM candidate target configuration for the target MCG cell or in the LTM candidate target configuration for the source MCG cell or in the LTM candidate target configuration for the MCG cell), where the UE is configured with the SCG.

[0210] Figure 9 A method according to a particular embodiment is depicted. Figure 9 The method may be performed by a network node (e.g., the network node 1510 or the network node 1700 described later with reference to Figure 15 and Figure 17 respectively). The network node may include a source node that provides the MCG to the user equipment. The method begins at step 902, where an LTM cell handover procedure from the source node to the target node is performed for the UE. In step 904, the method includes, during the execution of the LTM cell handover procedure, obtaining one or more actions related to a first SCG.

[0211] In other words, a source network node belonging to the master node (MN) or the master cell group (MCG) (also referred to as the source node) (such as a source gNB / eNB) may configure at least a secondary node (SN) or a secondary cell group (SCG) at the UE, and the SN or SCG is part of the LTM candidate target configuration when performing the LTM cell handover procedure from the source node or the target node within the MCG.

[0212] The one or more actions of step 904 may include one or more of the following:

[0213] Release the first SCG;

[0214] Suspend the first SCG,

[0215] Add the first SCG,

[0216] Reconfigure the first SCG,

[0217] Deactivate the first SCG,

[0218] Activate the first SCG,

[0219] Restore the first SCG; and

[0220] Continue to use the first SCG.

[0221] Specifically, some of these actions can be defined as follows: · Continue to Use the First SCG In this action, the SCG that is part of the LTM candidate cell configuration is the same as the existing SCG (which includes the first SCG in this example) configured at the UE before the LTM cell handover procedure is performed within the MCG. Alternatively, the LTM candidate cell configuration may include a field indicating that the UE continues to use the first SCG. In this case, when performing the LTM cell handover procedure within the MCG, the UE can simply continue to use the first (i.e., current) SCG without modifying any parameters / fields / structures related to the configuration of the first SCG. · Reconfigure the First SCG In this example, the UE reconfigures the existing SCG configured at the UE (the first SCG in this example) for the LTM cell handover procedure to generate a new SCG for the LTM candidate cell configuration. In other words, before performing the LTM cell handover within the MCG, the UE can apply the parameters / fields / structures related to the configuration of the new SCG on top of the existing first SCG configuration used by the UE. In this case, if the UE changes the existing configuration of the SCG by utilizing the new configuration received within the LTM candidate cell configuration when performing the LTM cell handover procedure, this reconfiguration can be regarded as a "full configuration". Otherwise, if the UE only changes a subset of the parameters / fields / structures related to those parameters / fields / structures present in the new cells received within the LTM candidate cell configuration when performing the LTM cell handover procedure, this reconfiguration can be regarded as a "delta configuration". · Activate, Deactivate, Suspend In this example, the first SCG can include either or both of the existing SCG configured at the UE before the LTM cell handover procedure or the new SCG that is part of the MTW candidate cell configuration. The first SCG configured by the UE and its state are set to "active" or "deactivated" or "paused". This means that the UE will apply the parameters / fields / structures related to the configuration of the first SCG, but will only start using the first SCG to perform transmission and reception after the LTM cell handover procedure is performed within the MCG when the state of the first SCG is changed to "active". After the LTM cell handover procedure is performed within the MCG, the state of the SCG can be changed to "active" by the target network or a third node (e.g., SN). Otherwise, setting the state of the first SCG to "active" or "deactivated" or "paused" can be indicated (within the same lower layer signaling in a different one) together with the lower layer signaling used to perform the LTM cell handover procedure within the MCG. · Release the First SCGA first SCG that is part of the LTM candidate cell configuration is indicated as not being used or released by the UE. This means that the UE will ignore the parameters / fields / structures related to the configuration of the first SCG received before performing the LTM cell handover procedure within the LTM candidate target cell configuration. This also means that if the UE has an existing SCG configured (and is in use), the UE will simply release the existing SCG after performing the LTM cell handover procedure and retain only the new MCG.

[0222] Figure 9 The source node of the method can determine to configure, at the UE, a first SCG that is part of the LTM candidate target configuration when performing an LTM cell handover procedure from a source network node to a target network node within the MCG. · In one alternative, the source network node determines to configure the first SCG at the UE based on measurements received by the UE before performing the LTM cell handover procedure within the MCG. In this example, step 904 includes determining one or more actions. For example, Figure 9 The method can further include: determining one or more actions based on measurements received by the UE before performing the LTM cell handover procedure. · In one alternative, the source network node determines to configure the first SCG at the UE based on an indication received from the target network node or from a third network node. In other words, step 904 can include receiving an indication of one or more actions from the target node or the third node.

[0223] When performing an LTM cell handover procedure within the MCG, the source network node sends an indication to the UE to configure a first SCG that is part of the LTM candidate target cell configuration. In other words, Figure 9 The method can further include sending an indication of one or more actions to the UE. · In one alternative, the indication is included in lower layer signaling. · The lower layer signaling can also indicate to the UE the LTM cell handover procedure within the MCG. In other words, the lower layer signaling can also request the LTM cell handover procedure. · In one alternative, the indication is implicit and is directly included within the configuration of the LTM candidate target cell when performing the LTM cell handover procedure within the MCG. · In one alternative, the indication is included in lower layer signaling that is different from the lower layer signaling used to indicate to the UE the performance of the LTM cell handover procedure within the MCG. In other words, the lower layer signaling including the indication is separate from the lower layer signaling requesting the LTM cell handover procedure.

[0224] Thus, it can be understood that two unique lower layer signaling indications from the source network node are used, one indicating to perform the LTM cell handover procedure within the MCG, and one indicating whether at least one SCG configured as part of the LTM candidate target configuration. · In one embodiment, the two lower layer signaling indications are sent to the UE in two unique messages (e.g., two MAC CE and MAC PDU). · In one embodiment, the two lower layer signaling indications are sent to the UE in the same message (e.g., two MAC CE within the same MAC PDU).

[0225] In some examples, the source network node only sends one of the two lower layer signaling indications, and the other is sent by the target network node or a third network node.

[0226] In some examples, step 904 includes sending a request for one or more actions to a third network node. For example, the source node may send a request to the third network node to configure an SCG at the UE, and the SCG is part of the LTM candidate target configuration when performing the LTM cell handover procedure from the source node or the target node within the MCG. · In an alternative, the source network node sends the request in a message sent through the Xn / X2AP interface. An example may be that the source network node sends the request to the third node via an S-NODE MODIFICATION REQUEST message. · In an alternative, the request may include one or more SCG configurations as part of the LTM candidate target cell configuration generated by the third network node, and the request is used for the third network node to indicate the SCG configuration to be configured.

[0227] In some examples, step 904 includes sending a request for one or more actions to the target node. For example, the source network node may send a request to the target network node to configure an SCG at the UE, and the SCG is part of the LTM candidate target configuration when performing the LTM cell handover procedure from the source node or the target node within the MCG. · In an alternative, the source network node sends the request in a message through the F1AP interface to the central unit (CU) to which the source network node is connected, and the CU forwards the request in a message through the F1AP interface to the target network node (since the target network node is also connected to the same CU). · In an alternative, the source network node sends the request in a message sent through the Xn / X2AP interface to the target network node. An example may be that the source network node sends the request to the third node via a handover request message.

[0228] In some examples, step 904 includes receiving an indication of one or more actions from a third network node. For example, the source node may receive from the third network node an indication to configure a first SCG at the UE, where the first SCG is part of an LTM candidate target configuration during the execution of an LTM cell handover procedure from the source node to the target node within the MCG. · In one alternative, the source network node receives the indication in a message sent via the Xn / X2AP interface. An example may be that the source network node receives the indication from the third node via an S-NODE MODIFICATION REQUEST ACKNOWLEDGE message. · In one alternative, the indication may include an SCG configuration that is not part of a previously sent LTM candidate target cell configuration generated by the third network node. In this case, the new SCG configuration may be considered part of the previously sent LTM candidate target cell configuration.

[0229] In some examples, step 904 includes receiving an indication of one or more actions from the target node. For example, the source node may receive from the target network node an indication to configure an SCG at the UE, where the SCG is part of an LTM candidate target configuration during the execution of an LTM cell handover procedure from the source node to the target node within the MCG. · In one alternative, the source network node receives the indication in a message sent by the CU to which the source network node is connected via the F1AP interface, which means that the target network node has transmitted the indication to the source network node via the CU. · In one alternative, the source network node receives the indication from the target network node in a message transmitted via the Xn / X2AP interface. An example may be that the source network node sends the request to the third node via a HANDOVER REQUEST ACKNOWLEDGE message. · In one alternative, the indication may include an SCG configuration that is not part of a previously sent LTM candidate target cell configuration generated by the third network node. In this case, the new SCG configuration may be considered part of the previously sent LTM candidate target cell configuration.

[0230] In some examples, Figure 9 the method further includes: receiving an indication of a second SCG that has been configured after the execution of the LTM cell handover procedure or will be configured during the execution of the LTM procedure. The second SCG may include the first SCG.

[0231] In other words, the source node may receive from the UE an indication of which SCG has been configured as part of the LTM candidate target cell configuration during the execution of the LTM cell handover procedure within the MCG. · In one alternative, the indication is included in the lower layer signaling sent by the UE before executing the LTM cell handover procedure within the MCG. · In one alternative, the indication is included in the lower layer signaling sent by the UE after executing the LTM cell handover procedure within the MCG. · In one alternative, the indication is included in the RRC message sent by the UE before executing the LTM cell handover procedure within the MCG.

[0232] It should be understood that one or more actions of the method according to Figure 9 may be applied to an existing SCG (if any) configured at the UE before executing the LTM cell handover procedure. In other words, the first SCG may be included as part of the UE configuration before the LTM cell handover procedure.

[0233] It should also be understood that one or more actions of the method according to Figure 9 may be applied to the SCG included in the LTM candidate target cell configuration sent to the UE before executing the LTM cell handover procedure. In other words, the first SCG may be included as part of the LTM candidate target configuration.

[0234] Figure 10 A method according to a particular embodiment is depicted. Figure 10 The method of Figure 15 and Figure 17 may be performed by a network node (e.g., network node 1510 or network node 1700 described later with reference to

[0235] In other words, a target network node belonging to the master node (MN) or the master cell group (MCG) (also referred to herein as the target node) (such as a target gNB / eNB) may configure at least a secondary node (SN) or a secondary cell group (SCG) at the UE, and the secondary node or SCG is part of the LTM candidate target configuration when performing the LTM cell handover procedure from the source node or the target node within the MCG.

[0236] One or more actions of step 1004 may include one or more of the following:

[0237] Release the first SCG;

[0238] Suspend the first SCG,

[0239] Add the first SCG,

[0240] Reconfigure the first SCG,

[0241] Deactivate the first SCG,

[0242] Activate the first SCG,

[0243] Resume the first SCG; and

[0244] Continue to use the first SCG.

[0245] Specifically, some of these actions may be defined as follows: · Continue to Use the First SCG . In this action, the SCG that is part of the LTM candidate cell configuration is the same as the existing SCG (which includes the first SCG in this example) configured at the UE before the LTM cell handover process is performed within the MCG. Alternatively, the LTM candidate cell configuration may include a field indicating that the UE continues to use the first SCG. In this case, when the LTM cell handover process is performed within the MCG, the UE may simply continue to use the first (i.e., current) SCG without modifying any parameters / fields / structures related to the configuration of the first SCG. · Reconfigure the First SCG . In this example, the UE reconfigures the existing SCG configured at the UE (the first SCG in this example) for the LTM cell handover process to produce a new SCG for the LTM candidate cell configuration. In other words, before the LTM cell handover is performed within the MCG, the UE may apply the parameters / fields / structures related to the configuration of the new SCG on top of the existing configuration of the first SCG used by the UE. In this case, if the UE changes the existing configuration of the SCG by utilizing the new configuration received within the LTM candidate cell configuration when performing the LTM cell handover process, this reconfiguration may be regarded as a "full configuration". Otherwise, if the UE only changes a subset of the parameters / fields / structures related to those parameters / fields / structures that exist in the new cell received within the LTM candidate cell configuration when performing the LTM cell handover process, this reconfiguration may be regarded as a "delta configuration".· Activate, Deactivate, Suspend。In this example, the first SCG can include one or both of an existing SCG configured at the UE prior to the LTM cell handover procedure or a new SCG that forms part of the MTW candidate cell configuration. The first SCG configured at the UE and its state are set to "active" or "deactivated" or "paused". This means that the UE will apply the parameters / fields / structures related to the configuration of the first SCG, but will only start using the first SCG to perform transmission and reception after the LTM cell handover procedure is executed within the MCG, only if the state of the first SCG is changed to "active". After the LTM cell handover procedure is executed within the MCG, the state of the SCG can be changed to "active" by the target network or a third node (e.g., SN). Otherwise, setting the state of the first SCG to "active" or "deactivated" or "paused" can be indicated (within the same lower layer signaling in a different one) together with the lower layer signaling used to execute the LTM cell handover procedure within the MCG. · Release the First SCG 。The first SCG that is part of the LTM candidate cell configuration is indicated to not be used or released by the UE. This means that the UE will ignore the parameters / fields / structures related to the configuration of the first SCG received prior to executing the LTM cell handover procedure within the LTM candidate target cell configuration. This also means that if the UE has an existing SCG configured (and is using it), the UE will simply release the existing SCG after executing the LTM cell handover procedure and only retain the new MCG.

[0246] Figure 10 The target node of the method can determine the SCG configured at the UE as part of the LTM candidate target configuration when performing the LTM cell handover procedure from the source node or the target node within the MCG. In one alternative, the target network node determines the first SCG configured at the UE based on the measurements received by the UE after the LTM cell handover procedure is executed within the MCG. In other words, step 1004 includes determining one or more actions. For example, the determination step can include determining one or more actions based on the measurements received by the UE after the LTM cell handover procedure is executed. In one alternative, the target network node determines to configure the SCG at the UE based on an indication received from the source network node or from a third network node. In other words, step 1004 can include receiving an indication of one or more actions from the source node or the third node.

[0247] The target network node can receive a request from a third network node to configure the SCG at the UE as part of the LTM candidate target configuration. For example, Figure 10 The method can further include receiving a request for one or more actions from a third network node. 1. In an alternative, the target network node receives the request in a message transmitted via the Xn / X2AP interface. An example could be that the source network node sends the request to a third node via an S-NODE MODIFICATION REQUEST or S-NODE CHANGE REQUIRED message. 2. In an alternative, the request may include one or more SCG configurations as part of a candidate target cell configuration for LTM generated by a third network node.

[0248] The target network node may receive a request from the source network node to configure an SCG at the UE as part of a candidate target configuration for LTM. For example, Figure 10 the method may further include receiving a request for one or more actions from the source node. a. In an alternative, the target network node receives the request in a message via the F1AP interface to a Central Unit (CU) to which both the source network node and the target network node are connected. This means that the CU has received the indication in a message via the F1AP interface from the source network node. For example, the source network node may send the request to the target network node via the CU. b. In an alternative, the target network node receives the request for the target network node in a message transmitted via the Xn / X2AP interface. An example could be that the source network node sends the request to a third node via a handover request message. c. In an alternative, the request may include one or more SCG configurations as part of a candidate target cell configuration for LTM generated by a third network node, and the request is for the third network node to indicate the SCG configuration to be configured.

[0249] In some examples, the target network node sends an indication to a third network node to configure an SCG at the UE as part of a candidate target configuration for LTM. In other words, Figure 10 the method may further include sending an indication of one or more actions to the third network node. a. In an alternative, the target network node receives the request for the target network node in a message transmitted via the Xn / X2AP interface. An example could be that the source network node sends the request to a third node via an S-NODE ADDITION REQUEST, S-NODE MODIFICATION REQUEST, or S-NODE RELEASE REQUEST message. b. In an alternative, the request may include one or more SCG configurations as part of the LTM candidate target cell configuration generated by a third network node, and the request is for the third network node to indicate the SCG configurations to be configured.

[0250] In some examples, the target network node sends an indication to the source network node to configure an SCG that is part of the LTM candidate target configuration at the UE. In other words, Figure 10 the method may further include sending an indication of one or more actions to the source node. a. In an alternative, the target network node sends the indication in a message via the F1AP interface to the central unit (CU) to which both the source network node and the target network node are connected. This means that the CU has received the indication in a message via the F1AP interface from the target network node. Basically, the target network node sends the indication to the source network node via the CU. b. In an alternative, the target network node sends the indication in a message via the Xn / X2AP interface. An example may be that the target network node sends the indication to the source node via a HANDOVER REQUEST ACKNOWLEDGE message. c. In an alternative, the indication may include an SCG configuration that is not part of a previously sent LTM candidate target cell configuration generated by the third network node. In this case, the new SCG configuration should be considered part of the previously sent LTM candidate target cell configuration.

[0251] Figure 10 The method may further include: after performing the LTM cell handover procedure, sending an indication of one or more actions to the UE. In other words, the target network node may send an indication to the UE for configuring an SCG that is part of the LTM candidate target configuration at the UE. a. In an alternative, the indication is included in the lower layer signaling sent to the UE after performing the LTM cell handover procedure within the MCG. b. In an alternative, the indication is included only in the RRC message sent to the UE after performing the LTM cell handover procedure within the MCG.

[0252] The target network node may receive an indication from the UE of which SCGs have been configured as part of the LTM candidate target cell configuration during the LTM cell handover procedure within the MCG. In other words, Figure 10 the method may further include: receiving an indication of a second SCG that has been configured after performing the LTM cell handover procedure. The second SCG may include the first SCG. a. In an alternative, the indication is included in the lower layer signaling sent by the UE after performing the LTM cell handover procedure within the MCG. b. In an alternative, the indication is included in the RRC message sent by the UE after performing the LTM cell handover procedure within the MCG.

[0253] It should be understood that one or more of the actions referred to above Figure 10 can be applied to an existing SCG (if any) configured at the UE before performing the LTM cell handover procedure. In other words, the first SCG can be part of the UE configuration before the LTM cell handover procedure.

[0254] It will be understood that one or more of the actions referred to above Figure 10 can be applied to the SCG included in the LTM candidate target cell configuration sent to the UE before performing the LTM cell handover procedure. In other words, the first SCG can be part of the LTM candidate target configuration.

[0255] Figure 11 depicts a method according to a particular embodiment. Figure 11 The method of Figure 15 and Figure 17 can be performed by a network node (e.g., the network node 1510 or the network node 1700 described separately later with reference to

[0256] The method can be performed by a third network node (e.g., a third node for providing a first secondary cell group (SCG)). The method starts at step 1102, where one or more actions related to the first secondary cell group are obtained before, during, or after performing a cell handover procedure for layer 1 / layer 2-based inter-cell mobility LTM of a user equipment from a source node to a target node for a primary cell group.

[0257] One or more of the actions in step 1102 can include one or more of the following:

[0258] Release the first SCG;

[0259] Suspend the first SCG,

[0260] Add the first SCG,

[0261] Reconfigure the first SCG,

[0262] Deactivate the first SCG,

[0263] Activate the first SCG,

[0264] Restore the first SCG; and

[0265] Continue to use the first SCG.

[0266] Specifically, some of these actions can be defined as follows:

[0267] Continue to Use the First SCG . In this action, the SCG that is part of the LTM candidate cell configuration is the same as the existing SCG (which includes the first SCG in this example) configured at the UE before performing the LTM cell handover procedure within the MCG. Alternatively, the LTM candidate cell configuration can include a field indicating that the UE continues to use the first SCG. In this case, when performing the LTM cell handover procedure within the MCG, the UE can simply continue to use the first (i.e., current) SCG without modifying any parameters / fields / structures related to the configuration of the first SCG.

[0268] Reconfigure the First SCG . In this example, the UE reconfigures the existing SCG (the first SCG in this example) configured at the UE to the LTM cell handover procedure to generate a new SCG for the LTM candidate cell configuration. In other words, before performing the LTM cell handover within the MCG, the UE can apply the parameters / fields / structures related to the configuration of the new SCG on top of the existing first SCG configuration used by the UE. In this case, if the UE changes the existing configuration for the SCG by using the new configuration received within the LTM candidate cell configuration when performing the LTM cell handover procedure, this reconfiguration can be considered a "full configuration". Otherwise, if the UE only changes a subset of the parameters / fields / structures related to those parameters / fields / structures present in the new cell received within the LTM candidate cell configuration when performing the LTM cell handover procedure, this reconfiguration can be considered a "delta configuration".

[0269] Activate, Deactivate, Suspend。In this example, the first SCG may include one or both of an existing SCG configured at the UE prior to the LTM cell handover procedure or a new SCG that forms part of the MTW candidate cell configuration. The first SCG configured at the UE and its state are set to "active" or "deactivated" or "paused". This means that the UE will apply the parameters / fields / structures related to the configuration of the first SCG, but will only start using the first SCG to perform transmission and reception after the LTM cell handover procedure is executed within the MCG, only if the state of the first SCG is changed to "active". How the state of the SCG is changed to "active" can be done by the target network or by a third node (e.g., the SN) after the LTM cell handover procedure is executed within the MCG. Otherwise, setting the state of the first SCG to "active" or "deactivated" or "paused" can be indicated together with the lower layer signaling used to execute the LTM cell handover procedure within the MCG (within the same lower layer signaling in a different one).

[0270] Release the First SCG 。The first SCG that is part of the LTM candidate cell configuration is indicated as not being used or released by the UE. This means that the UE will ignore the parameters / fields / structures related to the configuration of the first SCG received prior to executing the LTM cell handover procedure within the LTM candidate target cell configuration. This also means that if the UE has an existing SCG configured (and is using it), the UE will simply release the existing SCG after executing the LTM cell handover procedure and only retain the new MCG.

[0271] Figure 11 A third network node may determine to configure an SCG at the UE, which is part of the LTM candidate target configuration when executing the LTM cell handover procedure from a source node to a target node within the MCG. · In one alternative, after executing the LTM cell handover procedure within the MCG, the third network node determines to configure an SCG at the UE as part of the LTM candidate target configuration. · In some examples, step 1102 may include determining one or more actions. In one alternative, the third network node determines to configure an SCG at the UE based on measurements received by the UE prior to executing the LTM cell handover procedure within the MCG. In one alternative, the third network node determines to configure an SCG at the UE based on measurements received by the UE after executing the LTM cell handover procedure within the MCG. In other words, the determining step may include determining one or more actions based on measurements received by the UE after or after executing the LTM cell handover procedure. · In one alternative, the third network node determines to configure an SCG at the UE based on an indication received from the source network node or from the target network node.

[0272] The third network node may send an indication to the UE for configuring the SCG at the UE when performing the LTM cell handover procedure within the MCG. In other words, Figure 11 It may further include: sending an indication of one or more actions to the UE before or after the execution of the LTM cell handover procedure. · In an alternative, the indication is included in the configuration of the LTM candidate target cell sent to the UE before performing the LTM cell handover procedure within the MCG. · In an alternative, the indication is included in the configuration sent to the UE after performing the LTM cell handover procedure within the MCG. · In an alternative, the indication is included in the lower layer signaling sent to the UE after performing the LTM cell handover procedure within the MCG. · The indication is included in the lower layer signaling sent to the UE before performing the LTM cell handover procedure within the MCG.

[0273] The third network node may send an indication to the source network node for configuring the SCG at the UE when performing the LTM cell handover procedure. In other words, Figure 11 the method may include sending an indication of one or more actions to the source node. · In an alternative, the third network node sends the indication in a message sent through the Xn / X2AP interface. An example may be that the source network node sends the request to the third node via the S-NODE MODIFICATION REQUEST ACKNOWLEDGE message. · In an alternative, the request may include an SCG configuration that is not part of the previously sent LTM candidate target cell configuration generated by the third network node. In this case, the new SCG configuration should be considered as part of the previously sent LTM candidate target cell configuration. · In an alternative, the third network node sends the indication when receiving the same indication from the target network node.

[0274] The third network node may receive a request from the source network node for configuring the SCG as part of the LTM candidate target configuration at the UE. In other words, step 1104 may include receiving a request for one or more actions from the source node. · In an alternative, the third network node receives the request in a message transmitted through the Xn / X2AP interface. An example may be that the source network node sends the request to the third node via the S-NODE MODIFICATION REQUEST ACKNOWLEDGE message. · In an alternative, the request may include an SCG configuration that is not part of a previously sent LTM candidate target cell configuration generated by a third network node. In this case, the new SCG configuration shall be considered as part of the previously sent LTM candidate target cell configuration.

[0275] The third network node may receive an indication from the target network node of at least the SCG to be configured at the UE as part of the LTM candidate target configuration. For example, step 1104 may include receiving an indication of one or more actions from the target node. · In an alternative, the third network node receives the indication in a message transmitted via the Xn / X2AP interface. An example may be that the source network node sends the request to the third node via an S-NODE ADDITION REQUEST ACKNOWLEDGE, S-NODEMODIFICATION REQUIRED ACKNOWLEDGE, or S-NODE RELEASE REQUEST ACKNOWLEDGE message. · In an alternative, the indication may include one or more SCG configurations that are part of the LTM candidate target cell configuration generated by the third network node, and the request is for the third network node to indicate the SCG configuration to be configured.

[0276] It should be understood that one or more actions according to Figure 11 the method may be applied to an existing SCG (if any) configured at the UE before performing the LTM cell handover procedure.

[0277] It should be understood that one or more actions according to Figure 11 the method may be applied to the SCG included in the LTM candidate target cell configuration sent to the UE before performing the LTM cell handover procedure.

[0278] Figure 12 Illustrates Figures 8 to 11 an example implementation of the method of

[0279] In this example, step 1203 and step 1204 correspond to the source node obtaining one or more actions corresponding to step 904. In step 1206, the source node indicates one or more actions to the UE.

[0280] Figure 13 Illustrates Figures 8 to 11 an example implementation of the method of

[0281] In this example, the source node determines one or more actions and indicates one or more actions (SCG configuration indication) to the UE in step 1304.

[0282] Figure 14 shows an example implementation of Figures 8 to 11 the method of.

[0283] In this example, the source node obtains one or more actions (e.g., SCG configuration) from a third node via a target node in step 1406 (which corresponds to 904).

[0284] Figure 15 shows an example of a communication system 1500 according to some embodiments.

[0285] In this example, the communication system 1500 includes a telecommunications network 1502 and a core network 1506. The telecommunications network 1502 includes an access network 1504 such as a radio access network (RAN), and the core network 1506 includes one or more core network nodes 1508. The access network 1504 includes one or more access network nodes, such as network nodes 1510a and network nodes 1510b (one or more of which can generally be referred to as network nodes 1510), or any other similar 3rd Generation Partnership Project (3GPP) access node or non-3GPP access point. The network nodes 1510 support direct or indirect connections of user equipment (UE), such as connecting UEs 1512a, 1512b, 1512c, and 1512d (one or more of which can be generally referred to as UEs 1512) to the core network 1506 over one or more wireless connections.

[0286] Example wireless communications over wireless connections include transmitting and / or receiving wireless signals using electromagnetic waves, radio waves, infrared waves, and / or other types of signals suitable for communicating information without using wires, cables, or other material conductors. Additionally, in different embodiments, the communication system 1500 can include any number of wired or wireless networks, network nodes, UEs, and / or any other components or systems that can support or participate in the communication of data and / or signals via wired or wireless connections. The communication system 1500 can include and / or interface with any type of communication, telecommunications, data, cellular, radio network, and / or other similar types of systems.

[0287] The UE 1512 can be any of a variety of communication devices, including wireless devices arranged, configured, and / or operable to communicate wirelessly with network nodes 1510 and other communication devices. Similarly, the network nodes 1510 are arranged, capable, configured, and / or operable to communicate directly or indirectly with the UE 1512 and / or with other network nodes or devices in the telecommunications network 1502 to enable and / or provide network access, such as wireless network access, and / or perform other functions, such as management in the telecommunications network 1502.

[0288] In the depicted example, the core network 1506 connects the network node 1510 to one or more hosts, such as host 1516. These connections can be direct or indirect via one or more intermediate networks or devices. In other examples, the network node can be directly coupled to the host. The core network 1506 includes one or more core network nodes (e.g., core network node 1508) constructed using hardware and software components. The characteristics of these components can be substantially similar to those described with respect to the UE, network node, and / or host, such that the description generally applies to the corresponding components of the core network node 1508. Example core network nodes include functions of one or more of a mobile switching center (MSC), a mobility management entity (MME), a home subscriber server (HSS), an access and mobility management function (AMF), a session management function (SMF), an authentication server function (AUSF), a subscription identifier de-hiding function (SIDF), a unified data management (UDM), a security edge protection proxy (SEPP), a network exposure function (NEF), and / or a user plane function (UPF).

[0289] Host 1516 can be under the ownership or control of a service provider other than the operator or provider of the access network 1504 and / or the telecommunications network 1502, and can be operated by the service provider or on behalf of the service provider. Host 1516 can host various applications to provide one or more services. Examples of such applications include providing live and / or pre-recorded audio / video content, data collection services (e.g., retrieving and compiling data on various environmental conditions detected by multiple UEs), analytical functions, social media, functions for controlling or otherwise interacting with remote devices, functions for alarm and monitoring centers, or any other such functions performed by a server.

[0290] As a whole, Figure 15 the communication system 1500 enables connectivity between the UE, network node, and host. In this sense, the communication system can be configured to operate according to predefined rules or procedures, such as specific standards, including but not limited to: Global System for Mobile Communications (GSM); Universal Mobile Telecommunications System (UMTS); Long Term Evolution (LTE) and / or other suitable 2G, 3G, 4G, 5G standards or any applicable next-generation standards (e.g., 6G); Wireless Local Area Network (WLAN) standards, such as Institute of Electrical and Electronics Engineers (IEEE) 802.11 standards (WiFi); and / or any other suitable wireless communication standards, such as 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.

[0291] In some examples, the telecommunications network 1502 is a cellular network that implements 3GPP standardized features. Accordingly, the telecommunications network 1502 can support network slicing to provide different logical networks to different devices connected to the telecommunications network 1502. For example, the telecommunications network 1502 can provide ultra-reliable low-latency communication (URLLC) services to some UEs, while providing enhanced mobile broadband (eMBB) services to other UEs, and / or providing massive machine type communication (mMTC) / massive IoT services to additional UEs.

[0292] In some examples, the UE 1512 is configured to send and / or receive information without direct human interaction. For example, the UE can be designed to send information to the access network 1504 at a predetermined schedule when triggered by an internal or external event or in response to a request from the access network 1504. Additionally, the UE can be configured to operate in a single RAT or multi-RAT or multi-standard mode. For example, the UE can operate with any one or combination of Wi-Fi, NR (New Radio), and LTE, i.e., be configured for multi-radio dual connectivity (MR-DC), such as E-UTRAN (Evolved UMTS Terrestrial Radio Access Network) New Radio Dual Connectivity (EN-DC).

[0293] In Figure 15In the example shown, the hub 1514 communicates with the access network 1504 to support indirect communication between one or more UEs (e.g., UE 1512c and / or UE 1512d) and a network node (e.g., network node 1510b). In some examples, the hub 1514 can be a controller, a router, a content source and analysis node, or any other communication device described herein with respect to the UE. For example, the hub 1514 can be a broadband router that allows the UE to access the core network 1506. As another example, the hub 1514 can be a controller that sends commands or instructions to one or more actuators in the UE. The commands or instructions can be received from the UE, the network node 1510, or via executable code, scripts, procedures, or other instructions in the hub 1514. As another example, the hub 1514 can be a data collector that acts as a temporary storage for UE data and, in some embodiments, can perform analysis or other processing of the data. As another example, the hub 1514 can be a content source. For example, for a UE that is a VR headset, a display, a speaker, or other media delivery device, the hub 1514 can retrieve VR assets, videos, audio, or other media or data related to sensory information via the network node, and then the hub 1514 directly provides the VR assets, videos, audio, or other media or data to the UE after performing local processing and / or after adding additional local content. In yet another example, the hub 1514 acts as a proxy server or coordinator for the UE, particularly in the case where one or more UEs are low-energy IoT devices.

[0294] The hub 1514 can have a constant / persistent or intermittent connection to the network node 1510b. The hub 1514 can also allow different communication schemes and / or scheduling between the hub 1514 and the UE (e.g., UE 1512c and / or UE 1512d) and between the hub 1514 and the core network 1506. In other examples, the hub 1514 is connected to the core network 1506 and / or one or more UEs via a wired connection. Additionally, the hub 1514 can be configured to connect to an M2M service provider via the access network 1504 and / or to be connected to another UE via a direct connection. In some scenarios, the UE can establish a wireless connection with the network node 1510 while still being connected via the hub 1514 via a wired or wireless connection. In some embodiments, the hub 1514 can be a dedicated hub, i.e., its main function is to route communication from the network node 1510b to the UE / from the UE to the network node 1510b. In other embodiments, the hub 1514 can be a non-dedicated hub, i.e., a device capable of operating to route communication between the UE and the network node 1510b, but also capable of operating as a communication origin and / or destination for certain data channels.

[0295] Figure 16 FIG. 1600 shows a UE according to some embodiments. As used herein, a UE refers to a device capable of, configured to, arranged to, and / or operable to communicate wirelessly with network nodes and / or other UEs. Examples of UEs include, but are not limited to, smart phones, mobile phones, cellular phones, Internet Protocol voice (VoIP) phones, wireless local loop phones, desktop computers, personal digital assistants (PDAs), wireless cameras, gaming consoles or devices, music storage devices, playback appliances, wearable terminal devices, wireless endpoints, mobile stations, tablet computers, laptop computers, laptop embedded devices (LEEs), laptop mounted devices (LMEs), smart devices, wireless customer premises equipment (CPEs), in-vehicle or vehicle embedded / integrated wireless devices, and the like. Other examples include any UE identified by the 3rd Generation Partnership Project (3GPP), including narrowband Internet of Things (NB-IoT) UEs, machine type communication (MTC) UEs, and / or enhanced MTC (eMTC) UEs.

[0296] The UE may support device-to-device (D2D) communication, such as by implementing 3GPP standards for sidelink communication, dedicated short range communication (DSRC), vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I), or vehicle-to-everything (V2X). In other examples, the UE may not necessarily have a user in the sense of a human user owning and / or operating the associated device. Instead, the UE may represent a device intended to be sold to or operated by a human user but may not be associated with or initially associated with a particular human user (e.g., a smart sprinkler controller). Alternatively, the UE may represent a device not intended to be sold to or operated by an end user but may be associated with or operate for the benefit of a user (e.g., a smart meter).

[0297] The UE 1600 includes processing circuitry 1602, which is operably coupled via a bus 1604 to an input / output interface 1606, a power supply 1608, a memory 1610, a communication interface 1612, and / or any other components or any combination thereof. Some UEs may utilize Figure 16 all or a subset of the components shown in FIG. The level of integration between components may vary from one UE to another. Additionally, some UEs may include multiple instances of components, such as multiple processors, memories, transceivers, transmitters, receivers, etc.

[0298] The processing circuitry 1602 is configured to process instructions and data and may be configured to implement any sequential state machine operable to execute instructions stored as a machine-readable computer program in the memory 1610. The processing circuitry 1602 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, a general purpose processor (such as a microprocessor or a digital signal processor (DSP)) together with appropriate software; or any combination of the above. For example, the processing circuitry 1602 may include multiple central processing units (CPUs). The processing circuitry 1602 may be operable to provide UE 1600 functionality either alone or in conjunction with other UE 1600 components such as the memory 1610. For example, the processing circuitry 1602 may be configured to cause the UE 1602 to perform the methods as described with reference to Figure 8 Description method.

[0299] In this example, the input / output interface 1606 may be configured to provide one or more interfaces to an input device, an output device, or one or more input and / or output devices. Examples of output devices include speakers, sound cards, video cards, displays, monitors, printers, actuators, transmitters, smart cards, another output device, or any combination thereof. Input devices may allow a user to capture information into the UE 1600. Examples of input devices include touch-sensitive or presence-sensitive displays, cameras (e.g., digital cameras, digital video cameras, webcams, etc.), microphones, sensors, mice, trackballs, direction pads, touchpads, rollers, smart cards, etc. A presence-sensitive display may include a capacitive or resistive touch sensor to sense input from a user. The sensors may be, for example, accelerometers, gyroscopes, tilt sensors, force sensors, magnetometers, optical sensors, proximity sensors, biometric sensors, etc., or any combination thereof. Output devices may use the same type of interface port as the input devices. For example, a universal serial bus (USB) port may be used to provide input and output devices.

[0300] In some embodiments, the power supply 1608 is configured as a battery or battery pack. Other types of power supplies may be used, such as an external power supply (e.g., a power outlet), a photovoltaic device, or a battery. The power supply 1608 may also include power circuitry for delivering power from the power supply 1608 itself and / or an external power supply to various parts of the UE 1600 via an input circuitry or an interface such as a power cable. Delivering power may be, for example, for charging the power supply 1608. The power circuitry may perform any formatting, conversion, or other modification of the power from the power supply 1608 to make the power suitable for the corresponding components of the UE 1600 to which it is supplied.

[0301] The memory 1610 may be or be configured to include a memory such as a random access memory (RAM), a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), a magnetic disk, an optical disk, a hard disk, a removable cartridge, a flash drive, etc. In one example, the memory 1610 includes one or more application programs 1614 (such as an operating system, a web browser application, a widget, a gadget engine, or other applications) and corresponding data 1616. The memory 1610 may store any one or a combination of various operating systems used by the UE 1600.

[0302] The memory 1610 may be configured to include a plurality of physical drive units, such as a redundant array of independent disks (RAID), a flash memory, a USB flash drive, an external hard disk drive, a thumb drive, a pen drive, a key drive, a high density digital versatile disc (HD-DVD) optical disc drive, an internal hard disk drive, a Blu-ray disc drive, a holographic digital data storage (HDDS) optical disc drive, an external micro dual in-line memory module (DIMM), a synchronous dynamic random access memory (SDRAM), an external micro DIMM SDRAM, a smart card memory (such as a 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 an ISIM), other memories, or any combination thereof. The UICC may be, for example, an embedded UICC (eUICC), an integrated UICC (iUICC), or a removable UICC commonly referred to as a "SIM card". The memory 1610 may allow the UE 1600 to access instructions, application programs, etc. stored on a transient or non-transient memory medium to offload data or upload data. Such as an article of manufacture of a communication system may be tangibly embodied as or in the memory 1610, and the memory 1610 may be or include a device-readable storage medium.

[0303] The processing circuitry 1602 may be configured to communicate with an access network or other network using the communication interface 1612. The communication interface 1612 may include one or more communication subsystems and may include or be communicatively coupled to an antenna 1622. The communication interface 1612 may include one or more transceivers for communication, such as by communicating with one or more remote transceivers of another device capable of wireless communication (e.g., another UE or a network node in an access network). Each transceiver may include a transmitter 1618 and / or a receiver 1620 adapted to provide network communication (e.g., optical, electrical, frequency allocation, etc.). Additionally, the transmitter 1618 and the receiver 1620 may be coupled to one or more antennas (e.g., antenna 1622) and may share circuit components, software, or firmware, or alternatively be implemented separately.

[0304] In some embodiments, the communication functions of the communication interface 1612 may include cellular communication, Wi-Fi communication, LPWAN communication, data communication, voice communication, multimedia communication, short-range communication such as Bluetooth, near-field communication, location-based communication such as using the Global Positioning System (GPS) to determine location, another similar communication function, or any combination thereof. The communication may be implemented according to one or more communication protocols and / or standards, such as IEEE 802.11, Code Division Multiple 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 Network (SONET), Asynchronous Transfer Mode (ATM), QUIC, Hypertext Transfer Protocol (HTTP), etc.

[0305] Regardless of the type of sensor, the UE may provide an output of data captured by its sensors via a wireless connection to a network node through its communication interface 1612. The data captured by the UE's sensors may be transmitted to the network node via another UE through a wireless connection. The output may be periodic (e.g., every 15 minutes if it reports the sensed temperature), random (e.g., to equalize the payload from reports from several sensors), in response to a trigger event (e.g., sending an alert when moisture is detected), in response to a request (e.g., a user-initiated request), or a continuous stream (e.g., a real-time video feed of a patient).

[0306] As another example, the UE includes an actuator, a motor, or a switch associated with a communication interface configured to receive wireless input from a network node via a wireless connection. In response to the received wireless input, the state of the actuator, motor, or switch can be changed. For example, the UE can include a motor that adjusts the control surfaces or rotors of a drone in flight based on the received input, or controls a robotic arm performing a medical procedure based on the received input.

[0307] When in the form of an Internet of Things (IoT) device, the UE can be a device for use in one or more application domains, including but not limited to urban wearable technologies, extended industrial applications, and healthcare. Non-limiting examples of such IoT devices are devices or devices embedded in the following: connected refrigerators or cold rooms, TVs, connected lighting devices, electricity meters, robotic vacuum cleaners, voice-controlled smart speakers, home security cameras, motion detectors, thermostats, smoke detectors, door / window sensors, flood / moisture sensors, electric door locks, connected doorbells, air conditioning systems (such as heat pumps), autonomous vehicles, surveillance systems, weather monitoring devices, vehicle parking monitoring devices, electric vehicle charging stations, smart watches, fitness trackers, head-mounted displays for augmented reality (AR) or virtual reality (VR), wearable devices for tactile or sensory augmentation, sprinklers, animal or item tracking devices, sensors for monitoring plants or animals, industrial robots, unmanned aerial vehicles (UAVs), and any kind of medical device (such as a heart rate monitor or a remotely controlled surgical robot). The UE in the form of an IoT device includes, in addition to the other components described with respect to the Figure 16 UE 1600 shown, circuitry and / or software that depends on the intended application of the IoT device.

[0308] As yet another specific example, in an IoT scenario, the UE can represent a machine or other device that performs monitoring and / or measurement and sends the results of such monitoring and / or measurement to another UE and / or a network node. In this case, the UE can be an M2M device, which can be referred to as an MTC device in the 3GPP context. As a specific example, the UE can implement the 3GPP NB-IoT standard. In other scenarios, the UE can represent a means of transportation, such as a car, bus, truck, ship, and airplane, or other equipment capable of monitoring and / or reporting its operating status or other functions associated with its operation.

[0309] In fact, any number of UEs can be used together relative to a single use case. For example, the first UE can be or be integrated in a drone, and provide the speed information of the drone (obtained by a speed sensor) to the second UE which is a remote controller for operating the drone. When the user makes a change from the remote controller, the first UE can adjust the throttle on the drone (e.g., by controlling an actuator) to increase or decrease the speed of the drone. The first UE and / or the second UE can also include more than one of the above functions. For example, a UE can include sensors and actuators, and process data communication for both the speed sensor and the actuators.

[0310] Figure 17 FIG. 1700 shows a network node according to some embodiments. As used herein, a network node refers to a device that is capable of, configured to, arranged to, and / or operable to communicate directly or indirectly with a UE and / or other network nodes or devices in a telecommunication network. Examples of network nodes include, but are not limited to, access points (APs) (e.g., radio access points), base stations (BSs) (e.g., radio base stations, Node B, evolved Node B (eNB), and NR Node B (gNB)).

[0311] Base stations can be classified based on the amount of coverage they provide (or in other words, their transmit power levels), and thus depending on the amount of coverage provided, can be referred to as femto base stations, pico base stations, micro base stations, or macro base stations. A base station can be a relay node or a relay donor node controlling a relay. A network node can also include one or more (or all) parts of a distributed radio base station, such as a centralized digital unit and / or a remote radio unit (RRU), sometimes referred to as a remote radio head (RRH). Such a remote radio unit may or may not be integrated with an antenna into an antenna-integrated radio. The parts of a distributed radio base station can also be referred to as nodes in a distributed antenna system (DAS).

[0312] Other examples of network nodes include multi-transmission point (multi-TRP) 5G access nodes, multi-standard radio (MSR) devices 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, operation support system (OSS) nodes, self-organizing network (SON) nodes, positioning nodes (e.g., evolved serving mobile location center (E-SMLC)), and / or minimized drive test (MDT).

[0313] The network node 1700 includes processing circuitry 1702, a memory 1704, a communication interface 1706, and a power supply 1708 and / or any other components or any combination thereof. The network node 1700 may consist of multiple physically separated components (e.g., Node B components and RNC components, or BTS components and BSC components, etc.), and each component may have their own corresponding components. In some scenarios where the network node 1700 includes multiple separate components (e.g., BTS components 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 Node Bs. In such scenarios, each unique Node B and RNC pair may be considered as a single discrete network node in some instances. In some embodiments, the network node 1700 may be configured to support multiple radio access technologies (RATs). In such embodiments, some components may be replicated (e.g., separate memories 1704 for different RATs), and some components may be reused (e.g., the same antenna 1710 may be shared by different RATs). The network node 1700 may also include multiple sets of various shown components for different wireless technologies (e.g., GSM, WCDMA, LTE, NR, WiFi, Zigbee, Z-Wave, LoRaWAN, radio frequency identification (RFID), or Bluetooth wireless technologies) to be integrated into the network node 1700. These wireless technologies may be integrated into the same or different chips or chip sets and other components within the network node 1700.

[0314] The processing circuitry 1702 may include a combination of one or more of the following: a microprocessor, a controller, a microcontroller, a central processing unit, a digital signal processor, an application specific integrated circuit, a field programmable gate array, or any other suitable computing device, resource, or a combination of hardware, software, and / or coded logic, which is operable to provide the network node 1700 functions alone or in combination with other network node 1700 components such as the memory 1704. For example, the processing circuitry 1702 may be configured to cause the network node to perform the methods described with reference to Figure 9 , Figure 10 or Figure 11 .

[0315] In some embodiments, the processing circuitry 1702 includes a system-on-chip (SOC). In some embodiments, the processing circuitry 1702 includes one or more of radio frequency (RF) transceiver circuitry 1712 and baseband processing circuitry 1714. In some embodiments, the radio frequency (RF) transceiver circuitry 1712 and the baseband processing circuitry 1714 may be on separate chips (or chip sets), boards, or units (such as a radio unit and a digital unit). In alternative embodiments, some or all of the RF transceiver circuitry 1712 and the baseband processing circuitry 1714 may be on the same chip or set of chips, board, or unit.

[0316] The memory 1704 may include any form of volatile or non-volatile computer-readable memory, including but not limited to persistent storage devices, solid-state memory, remotely mounted memory, magnetic media, optical media, random access memory (RAM), read-only memory (ROM), mass storage media (e.g., hard disks), removable storage media (e.g., flash drives, compact discs (CDs), or digital video discs (DVDs)), and / or any other volatile or non-volatile, non-transitory device-readable and / or computer-executable memory device that stores information, data, and / or instructions that may be used by the processing circuitry 1702. The memory 1704 may store any suitable instructions, data, or information, including computer programs, software, applications, applications including logic, rules, code, tables, and / or other instructions that can be executed by the processing circuitry 1702 and utilized by the network node 1700. The memory 1704 may be used to store any calculations performed by the processing circuitry 1702 and / or any data received via the communication interface 1706. In some embodiments, the processing circuitry 1702 and the memory 1704 are integrated.

[0317] The communication interface 1706 is used for wired or wireless communication of signaling and / or data between a network node, an access network, and / or a UE. As shown in the figure, the communication interface 1706 includes (a plurality of) ports / (a plurality of) terminals 1716 for sending data to and receiving data from the network, for example, via a wired connection. The communication interface 1706 also includes radio front-end circuitry 1718, which may be coupled to an antenna 1710 or in some embodiments is part of the antenna 1710. The radio front-end circuitry 1718 includes a filter 1720 and an amplifier 1722. The radio front-end circuitry 1718 may be connected to the antenna 1710 and the processing circuitry 1702. The radio front-end circuitry may be configured to condition signals transmitted between the antenna 1710 and the processing circuitry 1702. The radio front-end circuitry 1718 may receive digital data to be transmitted to other network nodes or UEs via a wireless connection. The radio front-end circuitry 1718 may use a combination of the filter 1720 and / or the amplifier 1722 to convert the digital data into a radio signal having appropriate channel and bandwidth parameters. The radio signal may then be transmitted via the antenna 1710. Similarly, when receiving data, the antenna 1710 may collect radio signals, which are then converted into digital data by the radio front-end circuitry 1718. The digital data may be passed to the processing circuitry 1702. In other embodiments, the communication interface may include different components and / or different combinations of components.

[0318] In some alternative embodiments, the network node 1700 does not include a separate radio front-end circuitry 1718. Instead, the processing circuitry 1702 includes the radio front-end circuitry and is connected to the antenna 1710. Similarly, in some embodiments, all or some of the RF transceiver circuitry 1712 is part of the communication interface 1706. In other embodiments, the communication interface 1706 includes one or more ports or terminals 1716, radio front-end circuitry 1718, and RF transceiver circuitry 1712 as part of a radio unit (not shown), and the communication interface 1706 communicates with a baseband processing circuitry 1714 as part of a digital unit (not shown).

[0319] The antenna 1710 may include one or more antennas or antenna arrays configured to transmit and / or receive wireless signals. The antenna 1710 may be coupled to the radio front-end circuitry 1718 and may be any type of antenna capable of wirelessly transmitting and receiving data and / or signals. In some embodiments, the antenna 1710 is separate from the network node 1700 and may be connected to the network node 1700 via an interface or port.

[0320] The antenna 1710, communication interface 1706, and / or processing circuitry 1702 may be configured to perform any receiving operations and / or certain obtaining operations described herein as being performed by a network node. Any information, data, and / or signals may be received from a UE, another network node, and / or any other network device. Similarly, the antenna 1710, communication interface 1706, and / or processing circuitry 1702 may be configured to perform any sending operations described herein as being performed by a network node. Any information, data, and / or signals may be sent to a UE, another network node, and / or any other network device.

[0321] The power supply 1708 supplies power to the various components of the network node 1700 in a form suitable for the respective components (e.g., at the voltage and current levels required for each respective component). The power supply 1708 may also include or be coupled to power management circuitry to power the components of the network node 1700 to perform the functions described herein. For example, the network node 1700 may be connected to an external power supply (e.g., a power grid, a power outlet) via an input circuitry or interface such as a cable, and the external power supply powers the power circuitry of the power supply 1708. As another example, the power supply 1708 may include a power source in the form of a battery or battery pack, which is connected to or integrated in the power circuitry. The battery may provide backup power if the external power supply fails.

[0322] Embodiments of the network node 1700 may include additional components in addition to those shown in Figure 17 for providing functionality for certain aspects of the network node, including any functionality described herein and / or any functionality necessary to support the subject matter described herein. For example, the network node 1700 may include a user interface device to allow information to be input into the network node 1700 and to allow information to be output from the network node 1700. This may allow a user to perform diagnostic, maintenance, repair, and other administrative functions of the network node 1700.

[0323] Figure 18 is a block diagram of a host 1800 according to various aspects described herein, and the host 1800 may be an Figure 15 embodiment of the host 1516. As used herein, the host 1800 may be or may include various combinations of hardware and / or software, including a stand-alone server, a blade server, a cloud-implemented server, a distributed server, a virtual machine, a container, or processing resources in a server farm. The host 1800 may provide one or more services to one or more UEs.

[0324] The host 1800 includes processing circuitry 1802, which is operatively coupled via a bus 1804 to an input / output interface 1806, a network interface 1808, a power supply 1810, and a memory 1812. Other components may be included in other embodiments. The characteristics of these components may be substantially similar to those described for the devices in the previous figures (such as the attachments Figure 16 and Figure 17 ), such that the description generally applies to the corresponding components of the host 1800.

[0325] The memory 1812 may include one or more computer programs, which include one or more host applications 1814 and data 1816. The data 1816 may include user data, for example, data generated by the UE for the host 1800 or data generated by the host 1800 for the UE. Embodiments of the host 1800 may utilize only a subset or all of the illustrated components. The host applications 1814 may be implemented in a container-based architecture and may provide support for video codecs (such as Versatile Video Coding (VVC), High Efficiency Video Coding (HEVC), Advanced Video Coding (AVC), MPEG, VP9) and audio codecs (such as FLAC, Advanced Audio Coding (AAC), MPEG, G.711), including transcoding for multiple different categories, types, or implementations of the UE (such as handheld devices, desktop computers, wearable display systems, head-up display systems). The host applications 1814 may also provide user authentication and license checking and may periodically report health, routing, and content availability to a central node (such as a device in or on the edge of the core network). Accordingly, the host 1800 may select and / or indicate different hosts for over-the-top services for the UE. The host applications 1814 may support various protocols, such as the HTTP Live Streaming (HLS) protocol, the Real-Time Messaging Protocol (RTMP), the Real-Time Streaming Protocol (RTSP), the HTTP Dynamic Adaptive Streaming over HTTP (MPEG-DASH), etc.

[0326] Figure 19FIG. is a block diagram showing a virtualization environment 1900 in which functions implemented by some embodiments can be virtualized. In this context, virtualization means creating a virtual version of a device or equipment, which may include a virtualized hardware platform, storage devices, and networking resources. As used herein, virtualization can be applied to any device or its components described herein and involves an implementation in which at least a portion of the functions are implemented as one or more virtual components. Some or all of the functions described herein can be implemented as virtual components executed by one or more virtual machines (VMs), the one or more VMs being implemented in one or more virtualization environments 1900 hosted by one or more hardware nodes, such as a hardware computing device operating as a network node, UE, core network node, or host. Additionally, in embodiments where the virtual node does not require radio connectivity (e.g., a core network node or host), the node can be fully virtualized.

[0327] An application 1902 (which may alternatively be referred to as a software instance, virtual device, network function, virtual node, virtual network function, etc.) runs in the virtualization environment Q400 to implement some of the features, functions, and / or benefits of some embodiments disclosed herein.

[0328] Hardware 1904 includes processing circuitry, a memory storing software and / or instructions executable by the hardware processing circuitry, and / or other hardware devices as described herein, such as a network interface, input / output interface, etc. The software can be executed by the processing circuitry to instantiate one or more virtualization layers 1906 (also referred to as a hypervisor or virtual machine monitor (VMM)), provide VMs 1908a and 1908b (one or more of which can generally be referred to as VM 1908), and / or execute any of the functions, features, and / or benefits described with respect to some embodiments described herein. The virtualization layer 1906 can present a virtual operating platform that appears like networking hardware to the VMs 1908.

[0329] VM 1908 includes virtual processing, virtual memory, virtual networking or interfaces, and virtual storage, and can be run by the corresponding virtualization layer 1906. Different embodiments of instances of the virtual device 1902 can be implemented on one or more VMs 1908 and can be implemented in different ways. Virtualization of hardware is referred to as network function virtualization (NFV) in some contexts. NFV can be used to consolidate many network device types onto industry-standard high-volume server hardware, physical switches, and physical storage that can be located in data centers and customer premise equipment.

[0330] In the context of NFV, VM 1908 can be a software implementation of a physical machine running programs as if they were executing on a physical non-virtualized machine. Each VM in VM 1908, along with that part of the hardware 1904 that executes the VM, which is either hardware dedicated to that VM and / or hardware shared by that VM with other VMs in the VM, forms a separate virtual network element. Still in the context of NFV, the virtual network function is responsible for handling specific network functions that run in one or more VMs 1908 on top of the hardware 1904 and correspond to the application 1902.

[0331] The hardware 1904 can be implemented in an independent network node with general or specific components. The hardware 1904 can implement some functions via virtualization. Alternatively, the hardware 1904 can be part of a larger hardware cluster (e.g., in a data center or CPE), where many hardware nodes work together and are managed via management and coordination 1910, which in particular supervises the lifecycle management of the application 1902. In some embodiments, the hardware 1904 is coupled to one or more radio units, each radio unit including one or more transmitters and one or more receivers that can be coupled to one or more antennas. The radio units can communicate directly with other hardware nodes via one or more suitable network interfaces and can be used in combination with virtual components to provide a virtual node with radio capabilities, such as a radio access node or a base station. In some embodiments, a control system 1912 can be used to provide some signaling, and the control system 1912 can alternatively be used for communication between the hardware nodes and the radio units.

[0332] Figure 20 A communication diagram of a host 2002 communicating with a UE 2006 via a partial wireless connection through a network node 2004 according to some embodiments is shown. Now reference will be made to Figure 20 Describe example implementations of the UE (such as Figure 15 UE 1512a and / or Figure 16 UE 1600), network nodes (such as Figure 15 network node 1510a and / or Figure 17 network node 1700) and hosts (such as Figure 15 host 1516 and / or Figure 18 host 1800) discussed in the foregoing paragraphs according to various embodiments.

[0333] Similar to host 1800, an embodiment of host 2002 includes hardware such as a communication interface, processing circuitry, and memory. Host 2002 also includes software stored in or accessible by host 2002 and executable by the processing circuitry. The software includes a host application that can be operable to provide services to remote users, such as UE 2006 connected via an over-the-top (OTT) connection 2050 extending between UE 2006 and host 2002. When providing services to remote users, the host application can provide user data transmitted using OTT connection 2050.

[0334] Network node 2004 includes hardware that enables it to communicate with host 2002 and UE 2006. Connection 2060 can be direct or through a core network (such as Figure 15 core network 1506) and / or one or more other intermediate networks, such as one or more public, private, or managed networks. For example, the intermediate network can be a backbone network or the Internet.

[0335] UE 2006 includes hardware and software stored in or accessible by UE 2006 and executable by the processing circuitry of the UE. The software includes a client application, such as a web browser or a carrier-specific "app", that is operable to provide services to human or non-human users via UE 2006 with the support of host 2002. In host 2002, executing the host application can communicate with the executing client application via OTT connection 2050 terminated at UE 2006 and host 2002. When providing services to users, the client application of the UE can receive request data from the host application of the host and provide user data in response to the request data. OTT connection 2050 can transmit both request data and user data. The client application of the UE can interact with the user to generate the user data that it provides to the host application via OTT connection 2050.

[0336] OTT connection 2050 can extend via connection 2060 between host 2002 and network node 2004 and via wireless connection 2070 between network node 2004 and UE 2006 to provide a connection between host 2002 and UE 2006. Connection 2060 and wireless connection 2070 through which OTT connection 2050 can be provided have been drawn abstractly to show communication between host 2002 and UE 2006 via network node 2004 without explicitly referring to any intermediate devices and the exact routing of messages through these devices.

[0337] As an example of data transmission via the OTT connection 2050, in step 2008, the host 2002 provides user data, which can be performed by executing a host application. In some embodiments, the user data is associated with a specific human user interacting with the UE 2006. In other embodiments, the user data is associated with the UE 2006, and the UE 2006 shares data with the host 2002 without explicit human interaction. In step 2010, the host 2002 initiates a transmission carrying the user data to the UE 2006. The host 2002 can initiate the transmission in response to a request sent by the UE 2006. The request can be caused by a human interaction with the UE 2006 or an operation of a client application executed on the UE 2006. According to the teachings of the embodiments described throughout this disclosure, the transmission can be relayed via the network node 2004. Thus, according to the teachings of the embodiments described throughout this disclosure, in step 2012, the network node 2004 sends the user data carried in the transmission initiated by the host 2002 to the UE 2006. In step 2014, the UE 2006 receives the user data carried in the transmission, which can be performed by a client application executed on the UE 2006, and the client application is associated with the host application executed by the host 2002.

[0338] In some examples, the UE 2006 executes a client application that provides user data to the host 2002. The user data can be provided as a reaction or response to data received from the host 2002. Thus, in step 2016, the UE 2006 can provide user data, which can be performed by executing the client application. When providing the user data, the client application can also consider user input received from the user via the input / output interface of the UE 2006. Regardless of the specific manner of providing the user data, the UE 2006 initiates, in step 2018, a transmission of the user data to the host 2002 via the network node 2004. In step 2020, according to the teachings of the embodiments described throughout this disclosure, the network node 2004 receives the user data from the UE 2006 and initiates a transmission of the received user data towards the host 2002. In step 2022, the host 2002 receives the user data carried in the transmission initiated by the UE 2006.

[0339] One or more of the various embodiments improve the performance of the OTT service provided to the UE 2006 using the OTT connection 2050, where the wireless connection 2070 forms the last leg. More precisely, the teachings of these embodiments can increase the rate of providing the SCG, thus providing benefits such as improved performance.

[0340] In an example scenario, the host 2002 may collect and analyze factory status information. As another example, the host 2002 may process audio and video data that may have been retrieved from the UE for map creation. As another example, the host 2002 may collect and analyze real-time data to help control vehicle congestion (e.g., control traffic lights). As another example, the host 2002 may store surveillance videos uploaded by the UE. As another example, the host 2002 may store or control access to media content (such as video, audio, VR, or AR that it may broadcast, multicast, or unicast to the UE). As other examples, the host 2002 may be used for energy pricing, remotely controlling non-time-critical electrical loads to balance power generation demand, location services, rendering services (such as compiling maps from data collected from remote devices), or any other function of collecting, retrieving, storing, analyzing, and / or transmitting data.

[0341] In some examples, a measurement process may be provided for the purpose of monitoring data rate, latency, and other factors that may be improved in one or more embodiments. In response to a change in the measurement results, there may also be optional network functions for reconfiguring the OTT connection 2050 between the host 2002 and the UE 2006. The measurement process and / or network function for reconfiguring the OTT connection may be implemented in the software and hardware of the host 2002 and / or the UE 2006. In some embodiments, sensors (not shown) may be deployed in or associated with other devices through which the OTT connection 2050 passes; the sensors may participate in the measurement process by providing values of the monitored quantities illustrated above, or by providing values of other physical quantities from which the software can calculate or estimate the monitored quantities. The reconfiguration of the OTT connection 2050 may include message format, retransmission settings, preferred routing, etc.; the reconfiguration does not necessarily directly change the operation of the network node 2004. Such processes and functions may be known and practiced in the art. In certain embodiments, the measurement may involve proprietary UE signaling that supports the host 2002 in measuring throughput, propagation time, latency, etc. The measurement may be implemented because the software enables messages, particularly empty or "dummy" messages, to be sent using the OTT connection 2050 while monitoring propagation time, errors, etc.

[0342] Although the computing devices (e.g., UEs, network nodes, hosts) described herein may include a combination of the hardware components shown, other embodiments may include computing devices having a different combination of components. It should be understood that these computing devices may include any suitable combination of hardware and / or software required to perform the tasks, features, functions, and methods disclosed herein. The determination, calculation, acquisition, or similar operations described herein may be performed by a processing circuitry, which may process information by, for example, converting acquired information into other information, comparing the acquired information or the converted information with information stored in a network node, and / or performing one or more operations based on the acquired information or the converted information and making a determination as a result of the processing. Further, although a component is depicted as a single box located within a larger box or nested within multiple boxes, in practice, a computing device may include multiple different physical components that make up a single depicted component, and the functionality may be divided among separate components. For example, a communication interface may be configured to include any of the components described herein, and / or the functionality of a component may be divided between the processing circuitry and the communication interface. In another example, non-computationally intensive functions of any such component may be implemented in software or firmware, and computationally intensive functions may be implemented in hardware.

[0343] In some embodiments, some or all of the functions described herein may be provided by a processing circuitry that executes instructions stored in a memory, which in some embodiments may be a computer program product in the form of a non-transitory computer-readable storage medium. In alternative embodiments, some or all of the functions may be provided by a processing circuitry without executing instructions stored on a separate or discrete device-readable storage medium, such as in a hard-wired manner. In any of those particular embodiments, whether or not instructions stored on a non-transitory computer-readable storage medium are executed, the processing circuitry may be configured to perform the described functions. The benefits provided by such functions are not limited to the separate processing circuitry or other components of a computing device, but are generally enjoyed by the computing device and / or typically by an end user and a wireless network. Embodiment Group A Embodiments 1. A method performed by a user equipment that communicates with a source node in a master cell group (MCG), the method comprising: performing a layer 1 / layer 2 based inter-cell mobility (LTM) cell handover procedure from the source node to a target node, and performing one or more actions related to a first secondary cell group after or during performing the LTM cell handover procedure. 2. The method according to embodiment 1, wherein the one or more actions include one or more of the following: Release the first SCG, Suspend the first SCG, Add the first SCG, Reconfigure the first SCG, Deactivate the first SCG, Activate the first SCG, Resume the first SCG, and Continue to use the first SCG. 3. The method according to embodiment 1 or 2, further comprising: Determine one or more actions. 4. The method according to embodiment 1 or 2, further comprising: Receive an indication of one or more actions regarding the first SCG from a source node, a target node, or a third network node. 5. The method according to any of embodiment 4, wherein the method further comprises: Receive an indication of one or more actions in a radio resource control configuration. 6. The method according to any of embodiment 4, wherein the method further comprises: Receive an indication of one or more actions in lower layer signaling. 7. The method according to embodiment 6, wherein the lower layer signaling further requests to perform an LTM cell handover procedure. 8. The method according to embodiment 6 or 7, wherein the lower layer signaling is received from the target node. 9. The method according to embodiment 6 or 7, wherein the lower layer signaling is received from the source node. 10. The method according to embodiment 6 or 7, wherein the lower layer signaling is received from a third network node, wherein the third network node provides the first secondary cell group. 11. The method according to any of embodiment 3, wherein the method further comprises: Determine one or more actions based on measurements performed by the UE. 12. The method according to any of the previous embodiments, wherein the UE does not configure a new SCG for the LTM cell handover procedure, and the one or more actions include releasing the first SCG, wherein the first SCG includes an existing SCG. 13. The method according to any of embodiments 1 to 12, wherein the one or more actions include: deactivating or suspending the first SCG, regardless of the state associated with the first SCG within the LTM candidate target cell configuration used to perform the LTM cell handover procedure. 14. The method according to any of the previous embodiments, wherein the first SCG is part of the UE configuration prior to the LTM cell handover procedure. 15. The method according to any one of embodiments 1 to 13, wherein the first SCG comprises a part of the LTM candidate target configuration. 16. The method according to any of the foregoing embodiments further comprises: sending an indication of a second SCG, which has been configured after performing the LTM cell handover procedure or will be configured during the performance of the LTM procedure. 17. The method according to embodiment 16, wherein the indication is sent to a target node, a source node or a third node. 18. The method according to embodiments 16 to 17, wherein the second SCG comprises the first SCG. 19. The method according to any one of the foregoing embodiments further comprises: providing user data; and forwarding the user data to a host via a transmission to a network node. Group B Embodiments 20. A method performed by a source node providing a master cell group (MCG) to a user equipment, comprising: performing a layer 1 / layer 2 based inter-cell mobility LTM cell handover procedure from the source node to a target node for the user equipment; during the performance of the LTM cell handover procedure, obtaining one or more actions related to a first secondary cell group. 21. The method according to embodiment 20, wherein the one or more actions comprise one or more of the following: releasing the first SCG; pausing the first SCG, adding the first SCG, reconfiguring the first SCG, deactivating the first SCG, activating the first SCG, resuming the first SCG; and continuing to use the first SCG. 22. The method according to embodiment 20 or 21 further comprises: sending an indication of the one or more actions to the UE. 23. The method according to embodiment 22, wherein the indication is sent in low layer signaling. 24. The method according to embodiment 23, wherein the low layer signaling further requests the LTM cell handover procedure. 25. The method according to embodiment 23, wherein the low layer signaling comprising the indication is separated from the low layer signaling requesting the LTM cell handover procedure. 26. The method according to embodiment 22, wherein the indication is included in the LTM candidate target cell configuration. 27. The method according to any one of embodiments 21 to 26, wherein the first SCG comprises a part of the UE configuration before the LTM cell handover process. 28. The method according to any one of embodiments 21 to 26, wherein the first SCG comprises a part of the LTM candidate target configuration. 29. The method according to any one of embodiments 21 to 28, wherein the obtaining step comprises: Sending a request for one or more actions to a target network node. 30. The method according to any one of embodiments 21 to 29, wherein the obtaining step comprises: receiving an indication of one or more actions from a target network node. 31. The method according to any one of embodiments 21 to 28, wherein the obtaining step comprises: Sending a request for one or more actions to a third network node, wherein the third network node provides a first secondary cell group; and Receiving an indication of one or more actions from the third network node. 32. The method according to any one of embodiments 21 to 28, wherein the obtaining step comprises: Receiving an indication of one or more actions from a third network node. 33. The method according to any one of embodiments 21 to 28, further comprising: Determining one or more actions. 34. The method according to claim 33, wherein the determining step comprises: determining one or more actions based on measurements received by the UE before performing the LTM cell handover process. 35. The method according to any one of embodiments 21 to 34, further comprising: Receiving an indication of a second SCG, which has been configured after performing the LTM cell handover process or will be configured during the execution of the LTM process. 36. The method according to embodiment 35, wherein the second SCG comprises the first SCG. 37. A method for a target node to provide a master cell group (MCG) to a user equipment, comprising: Performing, for the user equipment, a layer 1 / layer 2-based inter-cell mobility LTM cell handover process from a source node to a target node in the MCG; Obtaining one or more actions related to a first secondary cell group after or during the execution of the LTM cell handover process. 38. The method according to embodiment 37, wherein the one or more actions comprise one or more of the following: Releasing the first SCG; Suspend the first SCG, Add the first SCG, Reconfigure the first SCG, Deactivate the first SCG, Activate the first SCG, Resume the first SCG; Continue to use the first SCG. 39. The method according to embodiment 37 or 38, further comprising: After performing the LTM cell handover procedure, send an indication of one or more actions to the UE. 40. The method according to embodiment 39, wherein the indication is sent in lower layer signaling. 41. The method according to embodiment 39, wherein the indication is included in an RRC message. 42. The method according to embodiment 37 or 38, further comprising: Send an indication of one or more actions to the source node or a third network node. 43. The method according to any one of embodiments 37 to 42, wherein the first SCG is part of the UE configuration before the LTM cell handover procedure. 44. The method according to any one of embodiments 37 to 42, wherein the first SCG is part of the LTM candidate target configuration. 45. The method according to any one of embodiments 37 to 44, wherein the method further comprises: Receive a request for one or more actions from the source node. 46. The method according to any one of embodiments 37 to 45, wherein the method further comprises: send an indication of one or more actions to the source node. 47. The method according to any one of embodiments 37 to 44, wherein the method further comprises: Receive a request for one or more actions from a third network node 48. The method according to any one of embodiments 37 to 44, wherein the method further comprises: Send an indication of one or more actions from a third network node. 49. The method according to any one of embodiments 37 to 44, wherein the obtaining step comprises: Determine one or more actions. 50. The method according to embodiment 49, wherein the determining step comprises: determining one or more actions based on measurements received by the UE after performing the LTM cell handover procedure. 51. The method according to any one of embodiments 37 to 50, further comprising: Receive an indication of a second SCG that has been configured after performing an LTM cell handover procedure. 52. The method according to embodiment 51, wherein the second SCG includes a first SCG. 53. A method performed by a third network node for providing a first secondary cell group to a user equipment, the method comprising: Obtain one or more actions related to the first secondary cell group before, during, or after performing layer 1 / layer 2 based inter-cell mobility LTM. 54. The method according to embodiment 37, wherein the one or more actions include one or more of the following: Release the first SCG; Suspend the first SCG, Add the first SCG, Reconfigure the first SCG, Deactivate the first SCG, Activate the first SCG, Resume the first SCG; and Continue to use the first SCG. 55. The method according to embodiment 53 or 54, further comprising: Send an indication of the one or more actions to the UE before or after performing the LTM cell handover procedure. 56. The method according to embodiment 55, wherein the indication is included in the LTM candidate target cell configuration. 57. The method according to embodiment 55, wherein the indication is included in lower layer signaling sent before or after performing the LTM cell handover procedure. 58. The method according to embodiment 53 or 54, further comprising: Send an indication of the one or more actions to the source node or the target node. 59. The method according to any one of embodiments 53 to 58, wherein the first SCG includes a part of the LTM candidate target configuration. 60. The method according to any one of embodiments 53 to 59, wherein the obtaining step comprises: Receive a request for one or more actions of the source node. 61. The method according to any one of embodiments 53 to 60, wherein the obtaining step comprises: receiving an indication of one or more actions from the target node. 62. The method according to any one of embodiments 53 to 59, further comprising: Determine one or more actions. 63. The method according to claim 64, wherein the determining step comprises: determining one or more actions based on measurements received by the UE after or subsequent to performing the LTM cell handover procedure. 64. The method according to any one of the foregoing embodiments, further comprising: Obtaining user data; Forwarding the user data to a host or a user equipment. Group C Implementations 65. A user equipment, comprising: Processing circuitry configured to cause the user equipment to perform any of the steps in any of the Group A embodiments of any of the steps; and Power circuitry configured to supply power to the processing circuitry. 66. A network node, comprising: Processing circuitry configured to cause the network node to perform any of the steps in any of the Group B embodiments of any of the steps; system Power circuitry configured to supply power to the processing circuitry. 67. A user equipment (UE) for [insert purpose], the UE comprising: An antenna configured to transmit and receive wireless signals; Radio front-end circuitry connected to the antenna and the processing circuitry and configured to condition signals transmitted between the antenna and the processing circuitry; Processing circuitry configured to perform any of the steps in any of the Group A embodiments; an input interface connected to the processing circuitry for allowing the processing circuitry to process information input to the user equipment; An output interface connected to the processing circuitry for outputting information of the user equipment processed by the processing circuitry; A battery connected to the processing circuitry for powering the UE. 68. A host configured to operate in a communication system to provide an over-the-top (OTT) service, the host comprising: Processing circuitry configured to provide user data; and A network interface configured to initiate transmission of the user data to a cellular network for transmission to a user equipment (UE), wherein the UE comprises a communication interface and processing circuitry, and the communication interface and processing circuitry of the UE are configured to perform any of the steps in any of the Group A embodiments to receive the user data from the host. 69. The host according to the foregoing embodiments, wherein the cellular network further includes a network node configured to communicate with the UE to send user data from the host to the UE. 70. The host according to the foregoing two embodiments, wherein: The processing circuitry of the host is configured to execute a host application to provide user data; and the host application is configured to interact with a client application executed on the UE, the client application being associated with the host application. 71. A method implemented by a host operating in a communication system, the communication system further including a network node and a user equipment (UE), the method including: Providing user data for the UE; and Initiating a transmission carrying the user data to the UE via a cellular network including the network node, wherein the UE performs any operation of any of the embodiments in Group A to receive the user data from the host. 72. The method according to the foregoing embodiments, further including: At the host, executing a host application associated with a client application executed on the UE to receive user data from the UE. 73. The method according to the foregoing embodiments, further including: At the host, sending input data to a client application executed on the UE, the input data being provided by executing the host application, wherein the user data is provided by the client application in response to the input data from the host application. 74. A host configured to operate in a communication system to provide an over-the-top (OTT) service, the host including: Processing circuitry configured to provide user data; and A network interface configured to initiate a transmission of the user data to a cellular network for transmission to a user equipment (UE), wherein the UE includes a communication interface and processing circuitry, the communication interface and processing circuitry of the UE being configured to perform any step of any of the embodiments in Group A to transmit the user data to the host. 75. The host according to the foregoing embodiments, wherein the cellular network further includes a network node configured to communicate with the UE to send user data from the UE to the host. 76. The host according to the foregoing two embodiments, wherein: The processing circuitry of the host is configured to execute a host application to provide user data; and the host application is configured to interact with a client application executed on the UE, the client application being associated with the host application. 77. A method implemented by a host configured to operate in a communication system, the communication system further including A network node and a user equipment (UE), the method comprising: At a host, receiving user data transmitted by the UE to the host via the network node, wherein the UE performs any step of the steps of any of the Group A embodiments to transmit the user data to the host. 78. The method according to the foregoing embodiment, further comprising: At the host, executing a host application associated with a client application executed on the UE to receive user data from the UE. 79. The method according to the foregoing embodiment, further comprising: At the host, sending input data to a client application executed on the UE, the input data being provided by executing the host application, wherein the user data is provided by the client application in response to the input data from the host application. 80. A host configured to operate in a communication system to provide an over-the-top (OTT) service, the host comprising: Processing circuitry configured to provide user data; and A network interface configured to initiate transmission of the user data to a network node in a cellular network for transmission to a user equipment (UE), the network node having a communication interface and processing circuitry, the processing circuitry of the network node being configured to perform any operation of any of the Group B embodiments to transmit the user data from the host to the UE. 81. The host according to the foregoing embodiment, wherein: The processing circuitry of the host is configured to execute a host application that provides user data; and the UE includes processing circuitry configured to execute a client application associated with the host application to receive transmission of the user data from the host. 82. A method implemented in a host configured to operate in a communication system, the communication system further including a network node and a user equipment (UE), the method comprising: Providing user data for the UE; and Initiating a transmission carrying the user data to the UE via a cellular network including the network node, wherein the network node performs any operation of any of the Group B embodiments to send the user data from the host to the UE. 83. The method according to the foregoing embodiment, further comprising sending, at the network node, the user data provided by the host for the UE. 84. The method according to any one of the foregoing two embodiments, wherein the user data is provided at the host by executing a host application that interacts with a client application executed on the UE, the client application being associated with the host application. 85. A communication system configured to provide an over-the-top service, the communication system comprising: A host, comprising: Processing circuitry configured to provide user data to a user equipment (UE), the user data being associated with an over-the-top service; and A network interface configured to initiate transmission of the user data towards a cellular network node for transmission to the UE, the network node having a communication interface and processing circuitry, the processing circuitry of the network node being configured to perform any operation of any embodiment of Group B embodiments to transmit the user data from the host to the UE. 86. The communication system according to the foregoing embodiment, further comprising: A network node; and / or A user equipment. 87. A host configured to operate in a communication system to provide an over-the-top (OTT) service, the host comprising: Processing circuitry configured to initiate reception of user data; and A network interface configured to receive user data from a network node in a cellular network, the network node having a communication interface and processing circuitry, the processing circuitry of the network node being configured to perform any operation of any embodiment of Group B embodiments to receive the user data from a user equipment (UE) for the host. 88. The host according to the foregoing embodiment, wherein: The processing circuitry of the host is configured to execute a host application to provide the user data; and the host application is configured to interact with a client application executing on the UE, the client application being associated with the host application. 89. The host according to any one of the foregoing two embodiments, wherein initiating reception of the user data comprises requesting the user data. 90. A method implemented by a host configured to operate in a communication system, the communication system further comprising a network node and a user equipment (UE), the method comprising: At the host, initiating reception of user data from the UE, the user data originating from a transmission that the network node has received from the UE, wherein the network node performs any step of any embodiment of Group B embodiments to receive the user data for the host from the UE. 91. The method according to the foregoing embodiment, further comprising, at the network node, transmitting the received user data to the host. References 1. RP-222332, 3GPP Work Item Description: First Step of NR Mobility Enhancement, MediaTek, 3GPP TSG RAN Meeting #97-e, Electronic Meeting, September 12 - 16, 2022 2. 3GPP TS 38.300 v17.1.0, NR and NG-RAN Overall Description; Stage 2 3. 3GPP TS 38.331, v17.1.0, RRC Protocol Specification 4. 3GPP TS 38.321, v17.1.0, MAC Protocol Specification Abbreviations At least some of the following abbreviations may be used in the present disclosure. If there is an inconsistency between abbreviations, the above description of how to use abbreviations shall be preferred. If listed multiple times below, the first listing shall be preferred over any subsequent (multiple) listings. 5GC or 5GCN 5G Core Network ACK Acknowledgment AGC Automatic Gain Control AMF Access and Mobility Management Function AP Application Protocol ARQ Automatic Repeat Request BFD Beam Failure Detection BFR Beam Failure Recovery BSR Beam State Report BWP Bandwidth Part C-RNTI Cell Radio Network Temporary Identifier CA Carrier Aggregation CE Control Element CGI Cell Global Identity CHO Conditional Handover CN Core Network CPA Conditional PSCell Addition CPC Conditional PSCell Change CP Control Plane CQI Channel Quality Indicator C-RNTI Cell Radio Network Temporary Identifier CSI Channel State Information CU Central Unit DC Dual Connectivity DCI Downlink Control Information DL Downlink DRB Data Radio Bearer DU Distributed Unit eNB (EUTRAN) base station E-RAB EUTRAN Radio Access Bearer E-UTRA Evolved Universal Terrestrial Radio Access E-UTRAN Evolved Universal Terrestrial Radio Access Network FDD Frequency Division Duplexing gNB NR base station GTP-U GPRS Tunneling Protocol – User Plane HARQ Hybrid ARQ IE Information Element IP Internet Protocol LTE Long Term Evolution MCG Master Cell Group MAC Media Access Control MAC CE MAC Control Element MeNB Master eNB MgNB Master gNB MN Master Node MR-DC Multi-Radio Dual Connectivity NACK Negative Acknowledgment NAS Non-Access Stratum NG-RAN Next Generation Radio Access Network Ng-eNB Next Generation evolved Node B NR New Radio PDCP Packet Data Convergence Protocol PCell Primary Cell PCI Physical Cell Identifier PDCCH Physical Downlink Control Channel PHR Power Headroom Report PSCell (in LTE) Primary SCG or (in NR) Primary SCG Cell PUCCH Physical Uplink Control Channel PUSCH Physical Uplink Shared Channel RACH Random Access Channel RAT Radio Access Technology RB Radio Bearer RLC Radio Link Control RLF Radio Link Failure RRC Radio Resource Control SCell SCG SCG SCG Group SCTP Stream Control Transmission Protocol Secondary eNB (SeNB) Secondary gNB (SgNB) Signal-to-Interference-plus-Noise Ratio (SINR) Secondary Node (SN) Scheduling Request (SR) Signaling Radio Bearer (SRB) Synchronization Signal Block (SSB) Source Secondary Node (S-SN) Supplementary Uplink (SUL) Special Cell (SpCell), the primary cell of the primary or SCG group Time Alignment Timer (TAT) Transmission Configuration Indicator (TCI) Time Division Duplex (TDD) Tunnel Endpoint Identifier (TEID) Transport Network Layer (TNL) Target Secondary Node (T-SN) Uplink Control Information (UCI) User Datagram Protocol (UDP) User Plane Function (UPF) User Equipment (UE) Uplink (UL) Uplink Shared Channel (UL-SCH) User Plane (UP) Ultra-Reliable and Low-Latency Communications (URLLC) Interface between base stations (X2) CDMA2000 1x Radio Transmission Technology (1x RTT) 3rd Generation Partnership Project (3GPP) 5th Generation (5G) 6th Generation (6G) Almost Blank Subframe (ABS) Automatic Repeat reQuest (ARQ) Additive White Gaussian Noise (AWGN) Broadcast Control Channel (BCCH) Broadcast Channel (BCH) Carrier Aggregation (CA) Carrier Component (CC) Common Control Channel Service Data Unit (CCCH SDU) Code Division Multiple Access (CDMA) Cell Global Identifier (CGI) Channel Impulse Response (CIR) Cyclic Prefix (CP) Common Pilot Channel (CPICH) CPICH Ec / No: The received energy per chip of CPICH divided by the power density in the frequency band CQI: Channel Quality Indicator C-RNTI: Cell RNTI CSI: Channel State Information DCCH: Dedicated Control Channel DL: Downlink DM: Demodulation DMRS: Demodulation Reference Signal DRX: Discontinuous Reception DTX: Discontinuous Transmission DTCH: Dedicated Traffic Channel DUT: Device Under Test E-CID: Enhanced Cell ID (location method) eMBMS: Evolved Multimedia Broadcast Multicast Service E-SMLC: Evolved Serving Mobile Location Center ECGI: Evolved CGI eNB: E-UTRAN Node B ePDCCH: Enhanced Physical Downlink Control Channel E-SMLC: Evolved Serving Mobile Location Center E-UTRA: Evolved UTRA E-UTRAN: Evolved UTRAN FDD: Frequency Division Duplexing FFS: For Further Study gNB: Base Station in NR GNSS: Global Navigation Satellite System HARQ: Hybrid Automatic Repeat reQuest HO: Handover HSPA: High Speed Packet Access HRPD: High Rate Packet Data LOS: Line of Sight LPP: LTE Positioning Protocol LTE: Long Term Evolution MAC: Media Access Control MAC: Message Authentication Code MBSFN: Multimedia Broadcast Multicast Service Single Frequency Network MBSFN ABS: MBSFN Almost Blank Subframe MDT: Minimization of Drive Tests MIB: Master Information Block MME: Mobility Management Entity MSC: Mobile Switching Center NPDCCH Narrowband Physical Downlink Control Channel NR New Radio OCNG OFDMA Channel Noise Generator OFDM Orthogonal Frequency Division Multiplexing OFDMA Orthogonal Frequency Division Multiple Access OSS Operation Support System OTDOA Observed Time Difference of Arrival O&M Operation and Maintenance PBCH Physical Broadcast Channel P-CCPCH Primary Common Control Physical Channel PCell Primary Cell PCFICH Physical Control Format Indicator Channel PDCCH Physical Downlink Control Channel PDCP Packet Data Convergence Protocol PDP Profile Delay Profile PDSCH Physical Downlink Shared Channel PGW Packet Data Network Gateway PHICH Physical Hybrid ARQ Indicator Channel PLMN Public Land Mobile Network PMI Precoder Matrix Indicator PRACH Physical Random Access Channel PRS Positioning Reference Signal PSS Primary Synchronization Signal PUCCH Physical Uplink Control Channel PUSCH Physical Uplink Shared Channel RACH Random Access Channel QAM Quadrature Amplitude Modulation RAN Radio Access Network RAT Radio Access Technology RLC Radio Link Control RLM Radio Link Management RNC Radio Network Controller RNTI Radio Network Temporary Identifier RRC Radio Resource Control RRM Radio Resource Management RS Reference Signal RSCP Received Signal Code Power RSRP Reference Symbol Received Power or Reference Signal Received Power RSRQ Reference Signal Receiving Quality or Reference Symbol Receiving Quality RSSI Received Signal Strength Indicator RSTD Reference Signal Time Difference SCH Synchronization Channel SCell Secondary Cell SDAP Service Data Adaptation Protocol SDU Service Data Unit SFN System Frame Number SGW Serving Gateway SI System Information SIB System Information Block SNR Signal-to-Noise Ratio SON Self-Organizing Network SS Synchronization Signal SSS Secondary Synchronization Signal TDD Time Division Duplex TDOA Time Difference of Arrival TOA Time of Arrival TSS Tertiary Synchronization Signal TTI Transmission Time Interval UE User Equipment UL Uplink USIM Universal Subscriber Identity Module UTDOA Uplink Time Difference of Arrival WCDMA Wide CDMA WLAN Wide Area Network

Claims

1. A method performed by a user equipment, the user equipment communicating with a source node in a master cell group (MCG), the method comprising: performing (802) a layer 1 / layer 2 based inter-cell mobility (LTM) cell handover procedure from the source node to a target node, and performing (804) one or more actions related to a first secondary cell group after or during performing the LTM cell handover procedure.

2. The method according to claim 1 or 2, further comprising: implementing the step of performing the LTM cell handover procedure in response to receiving lower layer signaling requesting the execution of the LTM cell handover procedure.

3. The method according to claim 1 or claim 2, wherein the one or more actions comprise one or more of the following: releasing the first SCG, suspending the first SCG, adding the first SCG, reconfiguring the first SCG, deactivating the first SCG, activating the first SCG, resuming the first SCG, and continuing to use the first SCG.

4. The method according to any one of claims 1 to 3, further comprising: receiving an indication of the one or more actions related to the first SCG from the source node, the target node, or a third network node.

5. The method according to claim 4, wherein the method further comprises: receiving the indication of the one or more actions in a radio resource control configuration.

6. The method according to claim 4, wherein the method further comprises: receiving the indication of the one or more actions in lower layer signaling.

7. The method according to claim 6 or claim 7, wherein the lower layer signaling is received from the target node, to the source node or a third network node, wherein the third network node provides the first secondary cell group.

8. The method according to any one of the preceding claims, wherein the one or more actions comprise releasing the first SCG, wherein the first SCG comprises an existing SCG, and after the LTM cell handover, the UE is only configured with the MCG and no SCG.

9. The method according to any one of the preceding claims, wherein the first SCG comprises a part of the UE configuration before the LTM cell handover procedure, or a part of the LTM candidate target configuration.

10. The method according to any one of the preceding claims, further comprising: sending an indication of a second SCG, the second SCG being configured after performing the LTM cell handover procedure, or to be configured during performing the LTM procedure.

11. The method according to claim 10, wherein the indication is sent to the target node, the source node, or a third node.

12. A method performed by a source node, the source node providing a master cell group (MCG) to a user equipment, the method comprising: performing (902) a layer 1 / layer 2 based inter-cell mobility (LTM) cell handover procedure from the source node to a target node for the user equipment; and During execution of the LTM cell handover procedure, obtain (904) one or more actions related to a first secondary cell group.

13. The method according to claim 12, further comprising: Sending lower layer signaling to the UE requesting execution of the LTM cell handover procedure.

14. The method according to claim 12 or claim 13, wherein the one or more actions include one or more of the following: Releasing the first SCG, Suspending the first SCG, Adding the first SCG, Reconfiguring the first SCG, Deactivating the first SCG, Activating the first SCG, Resuming the first SCG, and Continuing to use the first SCG.

15. The method according to any one of claims 12 to 14, further comprising: Sending an indication of the one or more actions to the UE.

16. The method according to claim 15, wherein the indication is sent in lower layer signaling or is included in the LTM candidate target cell configuration.

17. The method according to any one of claims 12 to 14, wherein the first SCG comprises a part of the UE configuration prior to the LTM cell handover procedure, or the first SCG comprises a part of the LTM candidate target configuration.

18. The method according to any one of claims 12 to 17, wherein the obtaining step comprises: Sending a request for the one or more actions to a target network node; And receiving an indication of the one or more actions from the target network node.

19. The method according to any one of claims 12 to 17, wherein the obtaining step comprises: Sending a request for the one or more actions to a third network node, wherein the third network node provides the first secondary cell group; And Receiving an indication of the one or more actions from the third network node.

20. The method according to any one of claims 12 to 19, further comprising: Receiving an indication of a second SCG that has been configured after execution of the LTM cell handover procedure, or will be configured during execution of the LTM procedure.

21. A method performed by a target node for providing a master cell group MCG to a user equipment, the method comprising: Performing (1002) a layer 1 / layer 2 based inter-cell mobility LTM cell handover procedure from a source node to the target node in the MCG for the user equipment, and Obtaining (1004) one or more actions related to a first secondary cell group after or during execution of the LTM cell handover procedure.

22. The method according to claim 21, wherein the one or more actions include one or more of the following: Releasing the first SCG, Suspending the first SCG, Adding the first SCG, Reconfiguring the first SCG, Deactivating the first SCG, Activating the first SCG, Resuming the first SCG, and Continuing to use the first SCG.

23. The method according to claim 21 or claim 22, further comprising: After execution of the LTM cell handover procedure, sending an indication of the one or more actions to the UE.

24. The method according to claim 23, wherein the indication is sent in low layer signaling or is included in an RRC message.

25. The method according to claim 21 or claim 22, further comprising: Sending an indication of the one or more actions to the source node or a third network node.

26. The method according to any one of claims 21 to 25, wherein the first SCG is part of the UE configuration before the LTM cell handover procedure or part of the LTM candidate target configuration.

27. The method according to any one of claims 21 to 26, wherein the method further comprises: Receiving a request for the one or more actions from the source node or a third network node.

28. The method according to any one of claims 21 to 27, wherein the method further comprises: Sending an indication of the one or more actions to the source node or a third network node.

29. The method according to any one of claims 21 to 28, further comprising: Receiving an indication of a second SCG that has been configured after performing the LTM cell handover procedure.

30. A method performed by a third network node for providing a first secondary cell group to a user equipment, the method comprising: Obtaining (1102) one or more actions related to the first secondary cell group before, during, or after performing a layer 1 / layer 2 based inter-cell mobility (LTM) cell handover procedure for the user equipment from a source node to a target node for a primary cell group.

31. The method according to claim 30, wherein the one or more actions comprise one or more of the following: Releasing the first SCG, Suspending the first SCG, Adding the first SCG, Reconfiguring the first SCG, Deactivating the first SCG, Activating the first SCG, Resuming the first SCG, and Continuing to use the first SCG.

32. The method according to claim 30 or claim 31, further comprising: Sending an indication of the one or more actions to the UE before or after performing the LTM cell handover procedure.

33. The method according to claim 32, wherein the indication is included in an LTM candidate target cell configuration or is included in low layer signaling.

34. The method according to claim 30 or claim 31, further comprising: Sending an indication of the one or more actions to the source node or the target node.

35. The method according to any one of claims 30 to 34, wherein the first SCG is part of an LTM candidate target configuration.

36. The method according to any one of claims 30 to 35, wherein the obtaining step comprises: Receiving a request for the one or more actions for the source node.

37. The method according to any one of claims 30 to 36, wherein the obtaining step comprises: Receiving an indication of the one or more actions from the target node.

38. A user equipment (UE) for communicating with a source node in a primary cell group, the UE comprising processing circuitry and a memory containing instructions executable by the processing circuitry, whereby the UE is operable to: perform (802) a layer 1 / layer 2 based inter-cell mobility (LTM) cell handover procedure from the source node to a target node, and perform (804) one or more actions related to a first secondary cell group after or during performing the LTM cell handover procedure.

39. The UE according to claim 38, wherein the memory contains further instructions executable by the processing circuitry, whereby the UE is operable to perform the method according to any one of claims 2 to 11.

40. A source node for providing a primary cell group (MCG) to a user equipment, the source node comprising processing circuitry and a memory containing instructions executable by the processing circuitry, whereby the source node is operable to: perform (902) a layer 1 / layer 2 based inter-cell mobility (LTM) cell handover procedure for the user equipment from the source node to a target node; and acquire (904) one or more actions related to a first secondary cell group during performing the LTM cell handover procedure.

41. The source node according to claim 40, wherein the memory contains instructions executable by the processing circuitry, whereby the source node is operable to perform the method according to any one of claims 13 to 20.

42. A target node for providing a primary cell group (MCG) to a user equipment, the target node comprising processing circuitry and a memory containing instructions executable by the processing circuitry, whereby the target node is operable to: perform (1002) a layer 1 / layer 2 based inter-cell mobility (LTM) cell handover procedure for the user equipment from a source node to the target node in the MCG, and acquire (1004) one or more actions related to a first secondary cell group after or during performing the LTM cell handover procedure.

43. The target node according to claim 42, wherein the memory contains further instructions executable by the processing circuitry, whereby the target node is operable to perform the method according to any one of claims 22 to 29.

44. A third network node for providing a first secondary cell group to a user equipment, the third network node comprising processing circuitry and a memory containing instructions executable by the processing circuitry, whereby the third network node is operable to: acquire (1102) one or more actions related to the first secondary cell group before, during or after performing a layer 1 / layer 2 based inter-cell mobility (LTM) cell handover procedure for the user equipment from a source node to a target node for a primary cell group.

45. The third network node according to claim 44, wherein the memory comprises further instructions executable by the processing circuitry, whereby the third network node is operable to perform the method as claimed in any one of claims 31 to 37.

46. A computer program comprising instructions which, when executed on at least one processor, cause the at least one processor to implement the method according to any one of claims 1 to 37.

47. A computer-readable medium comprising instructions which, when executed on at least one processor, cause the at least one processor to perform the method according to any one of claims 1 to 37.

48. A computer program product comprising a non-transitory computer-readable medium having stored thereon the computer program according to claim 46.

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