METHOD FOR SELECTIVE ACTIVATION OF CELL GROUPS

Description

METHOD FOR SELECTIVE ACTIVATION OF CELL GROUPS TECHNICAL FIELD

[0001] The present invention relates generally to wireless communications and, more specifically, to improved management of the mobility of wireless terminals through successive / subsequent conditional cell switching. BACKGROUND

[0002] Wireless communication technologies are moving the world toward greater network connectivity. Wireless communications depend on the efficient management of network resources and allocation between user stations and wireless access network nodes (including, but not limited to, wireless base stations) in a highly mobile environment. A next-generation network is expected to provide high-speed, low-latency, and ultra-reliable communication capabilities, while also meeting the requirements of different sectors and users. Mobile user stations or user equipment (UE) are becoming more complex to handle the increasing volume of data communications. To enhance communications and meet higher reliability requirements, improvements in mobility management are essential. SUMMARY

[0003] The present invention relates generally to wireless communications and, more specifically, to enhanced management of wireless terminal mobility through successive / subsequent conditional cell switching. Various exemplary implementations are provided to describe exemplary ways to prepare candidate SCG / PSCell configurations for selective SCG activation to support subsequent conditional PSCell addition / switching between multiple network elements, including indicating available / subsequent candidate PSCells from among all PSCells. Petition 870250089607, dated 02 / 10 / 2025, page 19 / 74 2 / 40 candidates to be evaluated when a candidate PSCell becomes a service PSCell during EU mobility.

[0004] In some implementations, a method is used for selective activation of cell groups for a wireless terminal in a wireless network performed by a Master Node (MN). The method may include sending a request message to a candidate Secondary Node (SN) to request the preparation of a selective activation procedure for a cell group for the wireless terminal; receiving a confirmation message from the candidate SN in response to the request message, where the confirmation message comprises an initial list of cell identifiers for a set of candidate cells; generating a reconfiguration message based on the confirmation message, where the reconfiguration message comprises a selective cell group activation configuration; and sending the reconfiguration message to the wireless terminal.

[0005] In the example implementation above, the confirmation message comprises a second list of SNs or candidate cells that correspond to one of the candidate cells in the set, the second list of SNs or candidate cells comprising subsequent candidates for Conditional Cell Change (CPC) when one of the candidate cells in the set becomes a current service cell for the wireless terminal.

[0006] In any of the example implementations above, the request message comprises at least one of the following: an indication to the candidate SN that the candidate SN is permitted to suggest subsequent candidate cells for a next / subsequent CPC for the wireless terminal; a list of suggested candidate SN or cell identifiers for the next / subsequent CPC; a maximum limit on the number of subsequent candidate cells that Petition 870250089607, dated 02 / 10 / 2025, page 20 / 74 3 / 40 can be prepared for the next / subsequent CPC for each candidate cell; a list of SN keys or a range of SN keys to be used for the next / subsequent CPC; or a counter value or a list of counter values ​​to be used for SN key derivation for the next / subsequent CPC.

[0007] In any of the example implementations above, the request message comprises an indication to the candidate SN that the candidate SN is permitted to suggest subsequent candidate cells for an upcoming / subsequent CPC; and the request message is received by the candidate SN to trigger the SN to perform at least one of the following: identify the set of candidate cells; identify the second list of SNs or candidate cells that correspond to one of the candidate cell set from MN suggestions if included in the request message; and determine the execution conditions for each of the second list of SNs or candidate cells based on a candidate cell measurement configuration.

[0008] In any of the example implementations above, the selective activation of groups of cells is initiated by the MN.

[0009] In any of the example implementations above, the selective activation of cell groups is initiated by a source SN in communication with the wireless terminal. The method may also include, before sending the request message to the candidate SN, receiving a required SN exchange message from the source SN. The required SN exchange message comprises at least one of the following: an indication to the MN that the candidate SN is permitted to suggest subsequent candidate cells for a next / subsequent CPC for the wireless terminal; a list of identifiers of suggested candidate SNs or cells for the next / subsequent CPC; or a maximum limit on the number of candidate cells. Petition 870250089607, dated 02 / 10 / 2025, page 21 / 74 4 / 40 subsequent that can be prepared for the next / subsequent CPC for each candidate cell by the candidate SN.

[0010] In any of the example implementations above, the generation of a reconfiguration message may include receiving a second confirmation message from at least one other candidate SN; and generating the reconfiguration message based on the confirmation message and the second confirmation message.

[0011] In any of the example implementations above, the method may also include generating a report and transmitting the report to the candidate SN to inform the candidate SN of a subset of subsequent candidates for conditional cell exchange that are included in the reconfiguration message for the wireless terminal.

[0012] In any of the example implementations above, the method may also include receiving, by the wireless terminal, a reconfiguration completed message in response to the reconfiguration message, where the reconfiguration completed message includes information to identify a target SN selected by the wireless terminal. The method may also include sending a reconfiguration completed message from the SN to the target SN.

[0013] In any of the example implementations above, the method may also include sending a report message to a source SN connected to the wireless terminal, the report message indicating to the source SN the selective activation procedure of the cell group for the source SN to maintain a wireless terminal context or to discard / release a current SN key.

[0014] In any of the example implementations above, the method may also include sending a report message to each of the other candidate SNs, the report message indicating to each of the other candidate SNs to hold or release. Petition 870250089607, dated 02 / 10 / 2025, page 22 / 74 5 / 40 a list of candidate cells prepared for the selective activation procedure of the cell group or to discard / release / update a candidate SN key.

[0015] In any of the example implementations above, the selective activation configuration of the cell group comprises at least one of the following: a list of prepared candidate cells; execution conditions for each of the prepared candidate cells in the list; a list of subsequent prepared candidate cells for each of the prepared candidate cells in the list; and execution conditions for each of the subsequent prepared candidate cells in the list.

[0016] In some other exemplary implementations, a method is described for selective activation of cell groups for a wireless terminal in a wireless network performed by a candidate SN. The method may include receiving a request message from a wireless terminal master node (MN) to request the preparation of a selective cell group activation procedure for the wireless terminal; preparing an initial list of cell identifiers for a set of candidate cells; and sending a confirmation message to the MN, wherein the confirmation message comprises the initial list of cell identifiers.

[0017] In the example implementations above, the method may further include preparing a second list of candidate SNs or cells that correspond to one of the candidate cell set, the second list of candidate SNs or cells comprising subsequent candidates for conditional cell exchange (CPC) when one of the candidate cell set becomes a current service cell for the wireless terminal, wherein the confirmation message further comprises the second list of candidate SNs or cells that correspond to one of the candidate cell set. Petition 870250089607, dated 02 / 10 / 2025, page 23 / 74 6 / 40

[0018] In any of the above exemplary implementations, the request message comprises at least one of the following: an indication to the candidate SN that the candidate SN is permitted to suggest subsequent candidate cells for a next / subsequent conditional cell exchange (CPC) for the wireless terminal; a list of suggested candidate SN or cell identifiers for the next / subsequent CPC; a maximum limit on the number of subsequent candidate cells that can be prepared for the next / subsequent CPC for each candidate cell; a list of SN keys or a range of SN keys to be used for the next / subsequent CPC; or a counter value or a list of counter values ​​to be used for SN key derivation for the next / subsequent CPC.

[0019] In any of the example implementations above, the method may also include receiving a report from the MN, the report informing the candidate SN of a subset of subsequent candidates for conditional cell selection that are not included in a reconfiguration message sent from the MN to the wireless terminal.

[0020] In some other implementations, a wireless communication device is described. The wireless communication device may include a processor and memory, where the processor is configured to read code from memory and implement any of the methods above.

[0021] In some other implementations, a computer-readable nontransient medium is described. The computer-readable nontransient medium may include computer instructions that, when executed by a processor of a wireless communication device, may cause the wireless communication device to implement any of the above methods. Petition 870250089607, dated 02 / 10 / 2025, page 24 / 74 7 / 40 BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 illustrates an exemplary wireless communication network that includes a wireless access network, a core network, and data networks.

[0023] Figure 2 illustrates an exemplary wireless access network that includes a plurality of mobile stations / terminals or user equipment (UEs) and a wireless access network node communicating with each other via a wireless radio communication interface.

[0024] Figure 3 shows an example architecture of a radio access network (RAN).

[0025] Figure 4 shows an example communication protocol stack in a wireless access network node or wireless terminal device, including various network layers.

[0026] Figure 5 illustrates the basic scenario for SN exchange.

[0027] Figure 6 illustrates groups of secondary cells that are candidates for subsequent conditional addition / exchange of PSCell.

[0028] Figure 7 shows an example of data and logic flow between various network elements for selective activation of a group of secondary cells.

[0029] Figure 8 shows another example of data flow and logic between various network elements for selective activation of a group of secondary cells. DETAILED DESCRIPTION

[0030] The present invention will be described in detail below, with reference to the accompanying drawings, which form part of this description and which show, by way of illustration, specific examples of embodiments. Note that the present invention can, however, be incorporated in a variety of different forms and, therefore, the Petition 870250089607, dated 02 / 10 / 2025, p. 25 / 74 8 / 40 subject matter covered or claimed should be interpreted as not being limited to any of the modalities to be presented below.

[0031] Throughout the descriptive report and claims, terms may have different meanings, suggested or implied in the context, in addition to an explicitly stated meaning. Similarly, the expression "in one embodiment" or "in some embodiments," as used herein, does not necessarily refer to the same embodiment, and the expression "in another embodiment" or "in other embodiments," as used herein, does not necessarily refer to a different embodiment. The expression "in one implementation" or "in some implementations," as used herein, does not necessarily refer to the same implementation, and the expression "in another implementation" or "in other implementations," as used herein, does not necessarily refer to a different implementation. For example, the claimed subject matter is intended to include combinations of exemplary embodiments or implementations, in whole or in part.

[0032] In general, terminology can be understood, at least in part, from its use in context. For example, terms such as and, or, or and / or, as used in this document, may include a variety of meanings that may depend, at least in part, on the context in which such terms are used. Typically, or, if used to associate a list, such as A, B, or C, is intended to mean A, B, and C, used in this document in an inclusive sense, as well as A, B, or C, used in this document in an exclusive sense. Furthermore, the terms one or more or at least one, as used in this document depending, at least in part, on the context, may be used to describe any feature, structure, or resource in an individual sense or may be used to describe Petition 870250089607, dated 02 / 10 / 2025, page 26 / 74 9 / 40 describe combinations of characteristics, structures, or features in the plural sense. Similarly, terms such as a, an, or the, again, can be understood to convey an individual use or to convey a plural use depending, at least in part, on the context. Furthermore, terms based on or determined by can be understood as not necessarily intended to convey an exclusive set of factors and may instead allow for the existence of additional factors not necessarily expressly described depending, again, at least in part, on the context. Wireless Network Overview

[0033] An exemplary wireless communication network, shown as 100 in Figure 1, may include wireless terminal devices or user equipment (UE) 110, 111 and 112, a carrier network 102, various service applications 140 and other data networks 150. Wireless terminal devices or UEs may alternatively be referred to as wireless terminals. The carrier network 102, for example, may include access network nodes 120 and 121 and a core network 130. The carrier network 110 may be configured to transmit voice, data and other information (collectively referred to as data traffic) between UEs 110, 111 and 112, between UEs and service applications 140 or between UEs and other data networks 150.Access network nodes 120 and 121 can be configured as multiple Wireless Access Network Nodes (WANNs, alternatively called wireless base stations) to interact with the UEs on one side of a communication session and with the central network 130 on the other. The term access network can be used more broadly to refer to a combination of wireless terminal devices 110, 111, and 112 and access network nodes 120 and 121. A wireless access network can alternatively be called a Network of. Petition 870250089607, dated 02 / 10 / 2025, page 27 / 74 10 / 40 Radio Access Network (RAN). The core network 130 may include multiple network nodes configured to control communication sessions and perform network access management and traffic routing. Service applications 140 may be hosted by multiple application servers deployed outside the core network 130, but connected to it. Similarly, other data networks 150 may also be connected to the core network 130.

[0034] In the example wireless communication network 100 in Figure 1, the UEs can communicate with each other through the wireless access network. For example, UEs 110 and 112 can be connected and communicate through the same node of the access network 120. The UEs can communicate with each other through the access networks and the main network. For example, UE 110 might be connected to access network node 120, while UE 111 might be connected to access network node 121, and as such, UE 110 and UE 111 can communicate with each other via access network nodes 120 and 121 and the core network 130. UEs can also communicate with service applications 140 and data networks 150 via the core network 130. Furthermore, UEs can communicate with each other directly via sidelink communications, as shown in 113.

[0035] Figure 2 further shows an exemplary system diagram of the wireless access network 120, including a WANN 202 that serves UEs 110 and 112 via wireless interface 204. The wireless transmission capabilities for wireless interface 204 include a combination of frequency, time, and / or spatial capabilities. Each of UEs 110 and 112 can be a mobile or fixed terminal device installed with mobile access units, such as SIM / USIM modules, to access the wireless communication network 100. UEs 110 and 112 can be implemented as a terminal device including, among others, a mobile phone, a smartphone, a tablet, a laptop, Petition 870250089607, dated 02 / 10 / 2025, page 28 / 74 11 / 40 a vehicle onboard communication device, a roadside communication device, a sensor device, a smart device (such as a television, a refrigerator, and an oven), or other devices capable of communicating wirelessly via a network. As shown in Figure 2, each of the UEs, such as UE 112, may include a transceiver circuit 206 coupled to one or more antennas 208 to effect wireless communication with the WANN 120 or with another UE, such as UE 110. The transceiver circuit 206 may also be coupled to a processor 210, which may also be coupled to a memory 212 or other storage devices. The memory 212 may be transient or non-transient and may store instructions or computer code which, when read and executed by the processor 210, cause the processor 210 to implement various of the methods described in this document.

[0036] Similarly, WANN 120 may include a wireless base station or other wireless network access point capable of wirelessly communicating via the over-the-air interface 204 with one or more UEs and communicating with the central network 130. For example, WANN 120 may be implemented, without limitation, in the form of a 2G base station, a 3G B node, an LTE eNB, a 4G LTE base station, a 5G NR base station of a 5G gNB, a 5G central unit base station, or a 5G distributed unit base station. Each type of these WANNs may be configured to perform a corresponding set of wireless network functions. WANN 202 may include a transceiver circuit 214 coupled to one or more antennas 216, which may include an antenna tower 218 in various shapes, to effect wireless communications with UEs 110 and 112.The transceiver circuit 214 can be coupled to one or more processors 220 which can also be coupled to a memory 222 or other storage devices. The memory 222 can be transient. Petition 870250089607, dated 02 / 10 / 2025, p. 29 / 74 12 / 40 or non-transient and may store instructions or codes that, when read and executed by one or more 220 processors, cause the one or more 220 processors to implement various WANN 120 functions described in this document.

[0037] Data packets in a wireless access network, such as the example described in Figure 2, can be transmitted as Protocol Data Units (PDUs). The included data can be packaged as PDUs at various network layers, encapsulated with nested and / or hierarchical protocol headers. PDUs can be communicated between a transmitting device or transmitting end (these two terms are used interchangeably) and a receiving device or receiving end (these two terms are also used interchangeably) once a connection (e.g., a Radio Link Control (RRC) connection) is established between the transmitting and receiving ends. Either transmitting or receiving device can be a wireless terminal device, such as devices 110 and 120 in Figure 2, or a wireless access network node, such as node 202 in Figure 2.Each device can be both a transmitter and a receiver for two-way communication.

[0038] The core network 130 in Figure 1 may include several geographically distributed network nodes interconnected to provide network coverage for a service region of the operator network 102. These network nodes may be implemented as dedicated hardware network nodes. Alternatively, these network nodes may be virtualized and implemented as virtual machines or as software entities. Each of these network nodes may be configured with one or more types of network functions that collectively provide the provisioning and routing functionalities of the core network 130.

[0039] Returning to the wireless radio access network (RAN), Figure Petition 870250089607, dated 02 / 10 / 2025, page 30 / 74 Figure 13 / 40 illustrates an exemplary RAN 340 communicating with a central network 310 and wireless terminals UE1 to UE7. RAN 340 may include one or more types of wireless base stations or WANs 320 and 321, which may include, among others, gNB, eNodeB, NodeB, or other types of base stations. RAN 340 may be redirected to the central network 310. The WANs 320, for example, may also include multiple separate access network nodes in the form of a Central Unit (CU) 322 and one or more Distributed Units (DU) 324 and 326. CU 322 is connected to DU1 324 and DU2 326 via various interfaces, for example, an F1 interface. The F1 interface, for example, may also include an F1-C interface and an F1-U interface, which can be used to carry information about the control plane and user plane data, respectively.In some embodiments, the CU may be a gNB Central Unit (gNB-CU) and the DU may be a gNB Distributed Unit (gNB-DU). Although the various implementations described below are provided in the context of a 5G cellular wireless network, the underlying principles described herein are applicable to other types of radio access networks including, but not limited to, other generations of cellular networks, as well as Wi-Fi, Bluetooth, ZigBee, and WiMax networks.

[0040] UEs can be connected to the network via WANNs 320 through a wireless interface. UEs can be serviced by at least one cell. Each cell is associated with a coverage area. These cells can alternatively be referred to as service cells. The coverage areas between cells may partially overlap. Each UE can be actively communicating with at least one cell, although it may potentially be connected to or connectable to more than one cell. In the example in Figure 1, UE1, UE2, and UE3 can be serviced by cell 1 330 of DU1, while UE4 and UE5 can be serviced by cell 2 332 of Petition 870250089607, dated 02 / 10 / 2025, page 31 / 74 14 / 40 DU1, UE6, and UE7 can be served by cell 3 associated with DU2. In some implementations, a UE can be served simultaneously by two or more cells. Each UE can be mobile, and the signal strength and quality of the various cells in the UE can depend on the UE's location and mobility.

[0041] Figure 4 further illustrates a simplified view of the various network layers involved in transmitting PDUs from the user plane of a transmitting device 402 to a receiving device 404 in the wireless access network exemplified in Figures 1 to 3. Figure 4 is not intended to include all essential device components or network layers for managing PDU transmission.Figure 4 illustrates that data packaged by the upper network layers 420 in the transmitting device 402 can be transmitted to the corresponding upper layer 430 (such as the Radio Resource Control or RRC layer) in the receiving device 304 via the Packet Data Convergence Protocol (PDCP) layer (not shown in Figure 4) and the Radio Link Control (RLC) layer 422, and from the transmitting device, the physical layers (PHY) of the transmitting and receiving devices and the radio interface, as shown in 406, and the Media Access Control (MAC) layer 434 and the RLC layer 432 of the receiving device. Multiple network entities in each of these layers can be configured to manage the transmission and retransmission of PDUs.

[0042] In Figure 4, the upper layers 420 can be referred to as layer 3 or L3, while the intermediate layers, such as the RLC layer and / or the MAC layer and / or the PDCP layer (not shown in Figure 4), can be collectively referred to as layer 2 or L2, and the term layer 1 is used to refer to layers such as the physical layer and the layers associated with the radio interface. Petition 870250089607, dated 02 / 10 / 2025, p. 32 / 74 15 / 40 In some cases, the term low layer may be used to refer to a set of L1 and L2, while the term high layer may be used to refer to layer 3. In some situations, the term lower layer may be used to refer to a layer between L1, L2, and L3 that is lower than a current reference layer. Control signaling can be initiated and triggered at each of the layers from L1 to L3 and within the various network layers contained within them. These signaling messages can be encapsulated and cascaded into lower-layer packets and transmitted via allocated control or data air radio resources and interfaces. The term layer generally includes several corresponding entities. For example, a MAC layer encompasses corresponding MAC entities that can be created. Layer 1, for example, encompasses PHY entities.Layer 2, on the other hand, encompasses MAC layers / entities, RLC layers / entities, Service Data Adaptation Protocol (SDAP) layers, and / or PDCP layers / entities. Conditional PSCell Addition / Change (CPAC)

[0043] The UE on the wireless network can be configured to operate in Dual Connectivity, including intra-EUTRA CC or Multi-Radio CC (MR-DC). In dual connectivity, the UE can be served by a primary node (MN) and a secondary node (SN). The MN and SN can be based on the same or different radio access technologies (RAT). For example, in the case of intra-EUTRA CC, both the MN and SN provide EUTRA access. In the case of MR-DC, one node provides NR access and the other provides EUTRA or NR access.

[0044] One or more service cells can be configured in either MN or SN. Service cells configured in MN Petition 870250089607, dated 02 / 10 / 2025, p. 33 / 74 16 / 40 are defined as a Master Cell Group (MCG), while service cells configured in SN are defined as a Secondary Cell Group (SCG). Within each cell group type, there may be a primary cell and one or more secondary cells. A primary cell in an MSG, for example, may be called a PCell, while a primary cell in an SCG may be called a PScell. Secondary cells in an MCG or SCG may be called SCell. Primary cells, including PCell and PScell, may be collectively referred to as spCell (special cell). All such cells may be referred to as service cells or cells. The terms cell and service cell may be used interchangeably in general unless specifically differentiated. The term service cell may refer to a cell that is servicing, will service, or may service the UE.In other words, a service cell may not be serving the UE at the moment. Although the various modalities described below may sometimes refer to one of the service cell types above, the underlying principles apply to all service cell types in both service cell group types.

[0045] Figure 5 illustrates a possible SN exchange scenario. Figure 5 shows three exemplary network nodes (e.g., Base Station), including MN (502), SN1 (504), and SN2 (506). Cell 1, Cell 2, and Cell 3 are exemplary corresponding cells generated by MN, SN1, and SN2, respectively. Cell 2 and Cell 3 are special cells of the secondary cell group (SCG), defined as the primary SCG cell (PSCell). X interfaces are deployed between MN and SN1 / SN2. At time T1, the UE may be operating in DC between MN and SN1. With the UE's movement, at time T2, the SN for the UE may change from SN1 to SN2. Such a SN exchange may be initiated by MN or by Petition 870250089607, dated 02 / 10 / 2025, page 34 / 74 17 / 40 Source SN (e.g., SN1).

[0046] In some situations, in 5G networks with small cells, cell swapping or SN swapping can be very frequent. To reduce downtime and improve mobility reliability (i.e., mobility robustness), Conditional PSCell Addition / Change (CPAC) can be implemented. CPAC is defined as a PSCell Addition / Change performed by the UE when the execution condition(s) is / are met. The UE starts evaluating the execution condition(s) upon receiving a CPAC configuration and stops evaluating the execution condition(s) as soon as the PSCell Addition / Change is triggered. The CPAC configuration, for example, may include the candidate PSCell configuration (including the SCG configuration generated by the candidate SN(s) and possibly the MCG configuration generated by the MN) and the corresponding execution condition(s) for the candidate PSCell.

[0047] The CPAC procedure can be triggered by the MN or the SN, and can be categorized as MN-initiated CPAC or SN-initiated CPAC. In addition, the CPAC procedure can be involved with or without MN, and can be classified as MN-involved CPAC or CPAC without MN involvement (i.e., intra-SN CPAC (Conditional PSCell Exchange) without MN involvement).

[0048] For CPA / CPC initiated by MN, the execution condition can be generated by MN, for example, Event A4, based on MCG MeasConfig. For CPC initiated by SN, the execution condition can be generated by the source SN, for example, Event A3 / A5, based on SCG MeasConfig. Events A3, A4, and A5 can be defined as the following occurrence: Event A3: The neighbor's measurement signal becomes better than PCell / PSCell by an amount of offset; Event A4: The neighbor's measurement signal becomes better than Petition 870250089607, dated 02 / 10 / 2025, page 35 / 74 18 / 40 is an absolute limit; Event A5: PCell / PSCell becomes worse than an absolute limit 1 AND Neighbor / SCell becomes better than another absolute limit 2. Selective Cell Group (CG) Activation

[0049] For selective activation of CG exchange, the NW can pre-configure multiple candidate CG configurations and send them to the UE. The UE stores the multiple candidate CG configurations. And the UE can perform CG exchange between candidate CGs based on the indication / signaling from the NW (e.g., RRC message, CE MAC) or on pre-configured execution conditions.

[0050] For simplicity, in the invention, hereinafter, the term candidate cell may also be referred to as candidate cell group (CG). CG may be used to represent one or both of the MCG and SCG groups. The term candidate cell may be used to refer to the candidate PCell in the MCG or the candidate PSCell in the SCG.

[0051] For MCG / PCell exchange, the term selective activation of CG exchange may be cited as subsequent / successive Conditional Handover (CHO) or selective activation of MCG / PCell exchange, selective activation of MCG / PCell, conditional selective MCG / PCell, and the like. Similarly, for SCG / PSCell exchange, the term selective activation of CG exchange may be cited as subsequent / successive Conditional PScell ​​Change (CPC), subsequent / successive Conditional PScell ​​Addition (CPA), selective activation of SCG / PSCell exchange, selective activation of SCG / PSCell, conditional selective SCG / PSCell, and the like.

[0052] In some of the implementations described below, the SCG / PSCell exchange (e.g., CPC) can be described as examples. The underlying principles and related solutions also apply to the MCG / PCell exchange. Petition 870250089607, dated 02 / 10 / 2025, p. 36 / 74 19 / 40

[0053] An example of a baseline procedure to support subsequent SCG / PSCell exchange is shown below: • The NW sends multiple candidate SCG / PSCell configurations and candidate SCG / PSCell execution conditions to the UE. • The UE stores multiple candidate SCG / PSCell configurations and evaluates the execution conditions of the candidate SCG / PSCell. When the execution condition of a candidate SCG / PSCell is met, the UE executes CPA or CPC against this candidate PSCell. • After completing the addition or exchange of the PSCell, the UE may not release the conditional configuration of other candidate PSCells for subsequent CPC and continues to evaluate the execution conditions of other candidate PSCells. • When the condition for executing a candidate PSCell is met, the UE may then execute subsequent CPCs in relation to this candidate PSCell.

[0054] In order to support subsequent CPAC, candidate SCG / PSCell configurations need to be maintained after an SCG / PSCell addition or swap (e.g., CPA / CPC or normal conditional PSCell addition / swap). When the UE switches to a specific candidate SCG / PSCell, some other candidate SCG / PSCells may not be suitable as candidates for the next SCG / PSCell swap (e.g., next CPC run). For example, as shown in Figure 6, there may be 7 candidate SCGs pre-configured by the NW for subsequent CPAC. When the UE moves to SCG_3, the neighbors SCG_2, SCG_4, and SCG_5 may be the candidate SCGs for the next SCG swap. However, other SCGs, such as SCG_1, SCG_6, and SCG_7, may not be suitable for the next SCG swap. Thus, NW can also indicate, for each candidate SCG, which candidate SCGs are available for the next [period / period]. Petition 870250089607, dated 02 / 10 / 2025, p. 37 / 74 20 / 40 SCG swap. The UE only needs to perform the execution conditions assessment for these available candidate SCGs when migrating to a specific SCG to avoid unnecessary assessments of other candidates and also to avoid frequent candidate updates via RRCRconfiguration (e.g., to release some candidates and add them again). In other words, the UE can maintain the configuration of all candidate SCGs / PSCells, but only needs to monitor and assess a subset of SCGs / PSCells for the subsequent SCG / PSCell swap. The subset of SCGs / PSCells is indicated by NW.

[0055] The various exemplary implementations are provided to describe exemplary ways to prepare candidate SCG / PSCell configurations for selective SCG activation (i.e., to support subsequent CPAC) across multiple network elements, including indicating the available / subsequent candidate PSCells from among all candidate PSCells to be evaluated when a candidate PSCell becomes a service PSCell during UE mobility. Illustrative Procedure and Signaling for Selective Activation of SCG

[0056] Figure 7 shows an exemplary data flow and logic 700 for selective activation of SCG. Selective activation of SCG can be initiated by MN. The exemplary data flow and logic in Figure 7 may include the following exchange of information between UE 702, MN 704, source SN 706, and candidate SNs 708 and 710:

[0057] Step 1: The MN sends a Request for Addition of SN message to a set of candidate SNs, for example, candidate SN 708 and another candidate SN 710 (only one of these candidates is tracked below) to request the preparation / initiation of the selective activation procedure of SCG. The message may include at least one Petition 870250089607, dated 02 / 10 / 2025, page 38 / 74 21 / 40 of the following information: • a maximum limit on the number of PSCells (candidate PSCells) that can be prepared by the candidate SN; • results of measurements related to the candidate SN; • a list of proposed candidate PSCells suggested from the source SN, for example, for selective activation of inter-SN SCG initiated by SN; • a reference SCG configuration (so that the candidate SN only needs to send the differential / delta configuration of the multiple candidate SCG configurations); • an indication to show that the request is for selective activation; • an indication to suggest that the candidate SN / PSCell may suggest subsequent candidate PSCells for the next / subsequent CPC; • a list of suggested subsequent candidate SN IDs for the next / subsequent CPC; • a list of suggested subsequent candidate PSCells for the next / subsequent CPC; • For each candidate PSCell prepared by the candidate SN, the maximum limit for the number of PSCells that can be prepared for the next / subsequent CPC; • a list of SN keys or a range of SN keys to be used for the next / subsequent CPC; • a counter value or a list of counter values ​​to be used for deriving the SN key for the next / subsequent CPC;

[0058] Step 2a: Based on the measurement results indicated by the MN and / or the list of PSCells suggested by the MN and / or the source SN, the SN Petition 870250089607, dated 02 / 10 / 2025, p. 39 / 74 22 / 40 candidate decides the list of PSCell(s) to be prepared (i.e., candidate PSCells initially prepared) and provides the SCG / candidate PSCell configuration for each prepared candidate PSCell (e.g., based on the reference SCG configuration such as, for example, a differential / delta candidate PSCell configuration). If an indication indicating that the request is for selective activation or an indication indicating that the SN / candidate PSCell may suggest / select subsequent candidate PSCells for the next / subsequent CPC is received, for each initially prepared candidate PSCell, the candidate SN decides / suggests / selects subsequent candidate SNs and / or subsequent candidate PSCells for that prepared candidate PSCell.If a list of suggested subsequent candidate SN IDs and / or subsequent candidate PSCells for the next / subsequent CPC is provided by the MN, the candidate SN selects the subsequent candidate SNs and / or PSCells from the list provided by the MN. The candidate SN may also provide execution conditions (e.g., execution conditions based on A3 / A5 events) for each subsequent candidate PSCell for the next / subsequent CPC. The execution condition may be based on the measurement configuration of the candidate SCG for the prepared candidate PSCell.

[0059] Step 2: The candidate SN sends a confirmation message requesting the addition of an SN to MN. The message may include a list of prepared candidate PSCell IDs and may also include at least one of the following pieces of information for each prepared candidate PSCell: • the candidate SCG / PSCell configuration; • a list of suggested candidate SNs and / or PSCells for the next / subsequent CPC, for example, a list of IDs of subsequent candidate PSCells (e.g., CGI); • the implementation conditions for each PSCell candidate Petition 870250089607, dated 02 / 10 / 2025, p. 40 / 74 23 / 40 subsequent suggested for the next / subsequent CPC;

[0060] Step 3: For each prepared candidate PSCell, if there are subsequent candidate PSCells, the MN can check if there is a prepared candidate PSCell configuration for the subsequent candidate PSCell (whose configuration may be generated by other candidate SNs). If there is a prepared candidate PSCell configuration, the MN generates the association between the candidate PSCell configuration and the execution conditions for the subsequent candidate PSCell. If there is no prepared candidate PSCell configuration for the subsequent candidate PSCell, the MN can initiate the SN addition procedure to a candidate SN to which the candidate PSCell belongs to request that the SN provide the SCG / candidate PSCell configuration for this PSCell. If there is a subsequent candidate PSCell whose candidate PSCell configuration and / or execution condition are not prepared, the MN may inform the candidate SN.For example, for each prepared candidate PSCell, the MN can inform the candidate SN which subsequent candidate PSCells have been prepared (e.g., the candidate cell whose configuration and associated execution condition have been prepared) via an Xn / X2 Message, for example, a SN modification request message. The message can include a list of initially prepared candidate PSCells. For each initially prepared candidate PSCell, there may be a list of subsequent candidate SNs and / or candidate PSCells that have been prepared for the next / subsequent CPC.

[0061] Step 4: If requested (for example, in response to message Xn / X2 in step 3 above), the candidate SN may send a reply message to the MN, for example, a request message to modify the SN.

[0062] In some example implementations, step 4 above and step 5 below can also be performed between the MN and Petition 870250089607, dated 02 / 10 / 2025, page 41 / 74 24 / 40 the source SN, for example, when the source SN is considered a candidate SN.

[0063] Step 5: The MN generates an RRCReconfiguration message that includes selective SCG activation configuration. The selective SCG activation configuration may include one or multiple reference configurations and a list of prepared candidate PSCells. For each prepared candidate PSCell, this may include the candidate PSCell ID (e.g., candidate PSCell configuration index, PCI+frequency), the SCG / candidate PSCell configuration, execution condition(s), a list of sk counters or SN keys, and / or the information for the next / subsequent CPC. For the prepared candidate PSCell, the information for the next / subsequent CPC may include a list of subsequent candidate PSCells to be evaluated when the prepared candidate PSCell becomes a service PSCell (e.g., after adding or swapping PSCells to the prepared candidate PSCell) and / or the execution conditions for each subsequent candidate PSCell.The MN sends the generated RRCReconfiguration message to the UE.

[0064] Step 6: The UE responds with an RRCReconfigurationComplete message to the MN.

[0065] Step 7: The MN can inform the source SN that the selective activation procedure of SCG is configured / prepared by means of an Xn / X2 message, for example, an Xn-U address indication message. If applicable, the source SN can initiate advance data forwarding.

[0066] Step 8: The UE begins evaluating the execution conditions. If the execution condition(s) for a candidate PSCell are met, the UE executes the CPAC procedure on the target PSCell. For example, the CPAC procedure might include applying the candidate cell configuration to that PSCell and performing random access to it. Petition 870250089607, dated 02 / 10 / 2025, p. 42 / 74 25 / 40 PSCell.

[0067] Step 9: The UE sends an RRCReconfigurationComplete message to the MN. The message may include information to allow the MN to identify the SN of the selected candidate PSCell.

[0068] Step 10: The MN sends the SNReconfigurationComplete message to the target SN. If there is a list of SN keys, the target SN will use the first SN key in the list for subsequent data transmission with the UE.

[0069] Steps 11a / b: The MN sends an Xn / X2 message (e.g., an SN Release Request message, an Xn-U Address Indication message, or another message) to inform the source SN and / or the candidate SN(s) about the execution of the CPC or CPA. The message may include an indication that the procedure is for selective SCG activation. Upon receiving the message, the SN may stop providing user data to the UE and / or trigger a delayed data forwarding procedure, if applicable. If the source SN is configured / considered as a candidate SN, the MN may indicate to the source SN that the UE context in the SN is maintained, for example, through an indication for selective SCG activation or an indication for maintaining the UE context in the message. If the indication is included, the SN may maintain the UE context. The source SN may drop / release / update the SN key that was used.Upon receiving the message, the source SN and / or candidate SNs can update the SN key that can be used when the UE returns to the same SN. The message to the source or candidate SN may indicate that the SN should release or hold the candidate PSCells or a list of candidate PSCells prepared for selective SCG activation. The source SN and / or candidate SNs can send a reply message (e.g., a SN Release Request Confirmation message) to the MN. Petition 870250089607, dated 02 / 10 / 2025, page 43 / 74 26 / 40

[0070] Step 12: OUE can synchronize with the selected target PSCell, for example, when performing random access.

[0071] Steps 13a-c: The UE can maintain the settings of candidate PSCells and perform the execution condition evaluation on the maintained candidate PSCells or on the candidate PSCells that are indicated to perform the execution condition evaluation for the next CPC (if indicated by NW). If the execution condition for a candidate PSCell is met, the UE performs the subsequent CPC execution for the selected target PSCell.

[0072] In some exemplary implementations, for example, before step 1, the MN may send a request message (e.g., SN addition or modification request message) to the source SN or candidate SN to request that the SN provide the SCG reference configuration, for example, including a hint for the reference configuration request. In response to receiving the message or the request hint, the source or candidate SN generates the SCG reference configuration and sends it to the MN, for example, via the SN addition or modification request confirmation message. The SCG reference configuration may be an RRCReconfiguration message generated by the SN.

[0073] In some exemplary implementations, the MN may send the configuration index of the candidate PSCell for each initial candidate PSCell prepared for the candidate SN. The candidate SN may associate the configuration index of the candidate PSCell and the corresponding execution conditions for the subsequent candidate PSCell. In this case, a list of subsequent candidate PSCells may be included in the candidate PSCell configuration for each initially prepared candidate PSCell.

[0074] Figure 8 shows another example 800 data flow and logic for selective activation of SCG. Selective activation of SCG Petition 870250089607, dated 02 / 10 / 2025, page 44 / 74 27 / 40 can be initiated by the source SN instead of the MN. The example data and logic in Figure 8 may include the following information exchange between UE 802, MN 804, source SN 806, and candidate SNs 808 and 810:

[0075] Step 1: The source SN initiates the selective activation procedure of SCG by sending a required SN exchange message to the MN. The message may include at least one of the following pieces of information: • a list of candidate SN IDs suggested by the source SN; • the results of measurements related to the candidate SN; • a list of proposed candidate PSCells recommended by the SN source; • the execution condition for each proposed PSCell candidate; • the maximum limit for the number of PSCells that can be prepared by each candidate SN; • the reference SCG configuration generated by the source SN; • an indication to show that the request is for selective activation; • an indication to show whether a candidate SN / PSCell can suggest subsequent candidate PSCells for the next / subsequent CPC; • For each candidate PSCell prepared by a candidate SN, the maximum limit for the number of PSCells that can be prepared for the next / subsequent CPC.

[0076] Steps 2 to 7 in Figure 8 are similar to Steps 1-6 in Figure 7.

[0077] Step 8: The MN can send an SN Exchange Confirmation message to the source SN to indicate to the source SN that the selective activation procedure for SCG is configured / ready. Petition 870250089607, dated 02 / 10 / 2025, page 45 / 74 28 / 40

[0078] Steps 9-14c in Figure 8 are similar to Steps 8-13c in Figure 7.

[0079] In some exemplary implementations, the selective activation configuration of SCG may include at least one of the following: • One or multiple reference configurations. The reference configuration may contain an RRCReconfiguration message. The reference configuration may include a reference GCM configuration and / or a reference SCG configuration; • a list of candidate SCG / PSCell configurations that may include at least one of the following: or a candidate PSCell ID, for example, candidate configuration index, PCI+frequency; the configuration of the candidate PSCell; The execution condition for the associated candidate PSCell. The execution condition can be used for MN-initiated CPAs and CPCs; either a list of sk counters or SN keys to be used for the candidate PSCell; or a reference configuration ID to indicate the reference configuration used for the candidate PSCell; • A list of information about the candidate PSCell to be used when the nominated candidate is the current PSCell. The information may include at least one of the following: A service / source PSCell ID: The ID can indicate the ID of the candidate PSCell in the list above, for example, candidate configuration index, PCI+frequency. When the UE's current service PSCell ID matches this PSCell ID, the UE uses the information in the associated / following list (i.e., a list of candidate PSCells to be evaluated) for the next CPC evaluation and execution; Petition 870250089607, dated 02 / 10 / 2025, p. 46 / 74 29 / 40 or a list of candidate PSCells to be evaluated, which may include at least one of the following: • A candidate PSCell ID, for example, candidate configuration index, PCI+frequency, to indicate the candidate PSCell to be evaluated and the associated candidate PSCell configuration from the SCG / candidate PSCell configuration list; • the execution condition for the associated candidate PSCell.

[0080] In some exemplary implementations, a list of candidate PSCells to be evaluated may be included in the candidate PSCell configuration.

[0081] An example of the signaling structure for selective SCG activation configuration is shown below: CandidatePSCellConfiqList -- a list of candidate PSCell configurations > CandidateConfigld -- the configuration ID of the candidate PSCell > CandidatePSCellConfig (including the RRCReconfiguration message) - candidate PSCell configuration > CondExecutionCondition -- the execution condition for the associated candidate PSCell > Sk-counterList -- a list of sk counters to be used for the candidate PSCell > ReferenceConfigld CandidatePSCellList — a list of information about the candidate PSCell > Source / serving PSCell ID (the ID can be PCI+frequency or the candidate PSCell configuration ID, for example, CandidateConfigld) — when the current service PSCell ID matches this PSCell ID, UE uses the information in CandidateToEvaluationList. Petition 870250089607, dated 02 / 10 / 2025, p. 47 / 74 30 / 40 associated for the evaluation and execution of CPC. > CandidateToEvaluationList -- a list of candidate PSCells to be evaluated when the currently in-service PSCell becomes the PSCell indicated in the candidate PSCell ID » CandidateConfigld -- to indicate the candidate PSCell to be evaluated and the associated candidate PSCell configuration from CandidatePSCelIConfigList » CondExecutionCondition -- the execution condition for the associated candidate PSCell.

[0082] The second list above for candidate PSCell information contains a second-level list of candidate PSCells, as described above. In some exemplary embodiments, the candidate SCG / PSCell configuration list and the candidate PSCell information list may be combined into a single list. For example, the candidate PSCell ID may be indicated by the candidate PSCell configuration ID. Candidate SCG / PSCell Configuration Management

[0083] When releasing or deactivating / enabling the SCG, the NW can explicitly indicate how to manage the stored candidate SCG / PSCell configurations, for example, whether to retain such candidate SCG / PSCell configurations and / or which candidate SCG / PSCell configurations should be retained (e.g., if they are needed for subsequent PSCell exchange / selection).

[0084] For example, if candidate SCG / PSCell configurations are retained after SCG release, the retained candidate SCG / PSCell configurations can be reused for subsequent CPA. In this case, retained candidate SCG / PSCells, for example, can be configured with A4 events (as described above) as execution conditions. For example, such execution conditions can be provided by the following alternatives: Petition 870250089607, dated 02 / 10 / 2025, p. 48 / 74 31 / 40 • Alt. 1: execution conditions are provided / updated via an RRCReconfiguration message indicating the release of the SCG. • Alt. 2: A4 event-based execution conditions can be pre-configured with candidate SCG / PSCell settings. For example, for each candidate SCG / PSCell, this can be associated with at least two sets of execution conditions: The set is based on A4 events, generated by MN, used for CPA or CPC initiated by MN; The other set is based on A3 / A5 events (which can be generated by the MN, source SN, or candidate SN) used for CPC.

[0085] In some exemplary implementations, for PCell exchange between MN, CPA / CPC settings can be released by the NW through an explicit indication.

[0086] In some example implementations, if the indication is sent from the source MN, a separate RRCReconfiguration message may be required before sending the HO command to the UE.

[0087] In some example implementations, if the indication is sent from the target MN, it may be necessary for the source MN to inform the target MN that the CPA / CPC has been configured for the UE and / or the list of candidate SCG / PSCells configured via an HO request message. Then, the target MN may include a release indication in the HO command (i.e., RRCReconfiguration message) to release the CPA / CPC configuration or to indicate which candidate PSCells should be released or retained, or the target MN may send a release indication via the RRCReconfiguration message after the UE successfully completes random access to the target PCell. Petition 870250089607, dated 02 / 10 / 2025, page 49 / 74 32 / 40 / - / anc / over Conditional (CHO) with Multiple SCGs Candidates

[0088] For CHO with candidate SCGs, the network provides the candidate PCell configuration with the candidate PSCell configuration (e.g., CHO configuration, including MCG and SCG configuration) and execution conditions for the candidate PCell and the candidate PSCells. Upon receiving the candidate configurations, the UE performs the evaluation of the candidate PCells and the candidate PSCells simultaneously. When the execution conditions for the candidate PCell and the candidate PSCell are met simultaneously, the UE performs the CHO procedure with SCG to access the target PCell and PSCell.

[0089] In some exemplary implementations, the CHO preparation procedure with candidate SCGs is initiated by the source MN. The procedure may include at least one of the following steps:

[0090] Step 1: The source MN sends a handover request message to the candidate MN. The message may include the ID of the requested candidate PCell, an indication to show that the request is for CHO with candidate SCGs and / or an indication to request that the candidate MN generate the execution conditions for the prepared candidate PSCell.

[0091] Step 2: The candidate MN decides the candidate SN(s) for the requested candidate PCell and sends an SN addition request message to each candidate SN to request that the candidate SN prepare the candidate PSCell. If the candidate SN is the same node as the source SN, the candidate MN can instruct the SN to generate / provide the execution condition for the prepared candidate PSCells. The execution condition is generated based on the source SCG measurement configuration.

[0092] Step 3: The candidate SN responds to the confirmation message for the request to add an SN to the candidate MN. The message Petition 870250089607, dated 02 / 10 / 2025, p. 50 / 74 33 / 40 may include the ID of the prepared candidate PSCell, the candidate SCG / PSCell configuration, the execution condition, and / or the updated source SCG measurement configuration (if the candidate SN is the same node as the source SN).

[0093] Step 4: The candidate MN generates the candidate configuration for the PCell and PSCell (i.e., MN RRCReconfiguration message with MCG and SCG configuration). The candidate MN may generate the execution condition for the prepared candidate PSCell (e.g., A4 event threshold). The candidate MN then sends a handover request confirmation message to the source MN. The message may include at least one of the following: • the configuration for the PCell and PSCell candidates; • the ID(s) of the associated candidate PSCell for the candidate PCell; • the execution conditions generated by the candidate MN; • the execution conditions generated by the candidate SN, if the candidate SN is the same node as the source SN; • the updated source SCG measurement configuration (if the candidate SN is the same node as the source SN); or • an indication to indicate / request that the source SN or source MN generate the execution conditions for the prepared candidate PSCell.

[0094] Step 5: If the execution conditions for the candidate PSCell generated by the MN are received, the source MN can generate / translate the execution conditions based on the source MCG MeasConfig for the UE according to the information received from the candidate MN. For example, the source MN configures the CondEvent A4 associated with the frequency of the candidate PSCell in the measurement configuration of the source MCG using the threshold value defined by the candidate MN. If an indication to indicate / request the source MN to generate the execution conditions for the Petition 870250089607, dated 02 / 10 / 2025, page 51 / 74 34 / 40 If a prepared candidate PSCell is received, or if no execution condition is received for the prepared candidate PSCell, the source MN generates the execution conditions based on the measurement configuration of the source MCG for the candidate PSCell. If an indication to instruct / request the source SN to generate the execution conditions for the prepared candidate PSCell is received, the source MN sends an SN request message (e.g., SN modification request message) to the source SN to request that the source SN generate the execution conditions. The request message may include the ID(s) of the prepared candidate PSCell and / or an indication to generate the execution condition.The source SN generates the execution conditions based on the source SCG MeasConfig and responds with an SN request confirmation (e.g., SN modification request confirmation message) to the source MN, including the generated execution conditions for the prepared candidate PSCell and / or updated source SCG measurement configuration.

[0095] Step 6: The source MN generates the RRCReconfiguration message, including the CHO, with candidate SCG configurations and sends the message to the UE. The CHO with candidate SCG configurations includes the configuration for the candidate PCell and candidate PSCell and associated execution conditions for the candidate PCell and PSCell. Reference Configuration Management and Candidate Configuration

[0096] The network can pre-configure multiple candidate cell configurations for mobility, for example, L1 / L2 triggered mobility (LTM), CHO, CPAC, selective activation of cell groups, etc. A reference configuration can be provided by the network, such as the baseline candidate cell configuration, to reduce signaling overhead.

[0097] LTM is a procedure in which a gNB receives reports Petition 870250089607, dated 02 / 10 / 2025, page 52 / 74 35 / 40 of the L1 measurement of UEs and, based on the reports, the gNB swaps the UE service cell(s) via a cell swap command using an L1 or L2 signal (e.g., DCI or MAC CE), which indicates a previously prepared LTM candidate cell configuration provided to the UE via RRC signaling. The cell swap is then triggered by selecting the LTM candidate cell configuration indicated as the target configuration by the gNB.

[0098] In some exemplary implementations, a separate reference configuration may be explicitly provided by the network. Upon receiving the reference configuration, the UE stores it separately.

[0099] In some exemplary implementations, a separate reference configuration is not provided by the network, i.e., there is no separate reference configuration. The network indicates a candidate cell configuration as the reference configuration. Upon receiving the indication, the UE stores the indicated candidate cell configuration as a separate reference configuration.

[0100] In some example implementations, a separate reference configuration is not provided by the network, i.e., there is no separate reference configuration. The network provides the candidate cell configuration as either a candidate delta configuration based on the current UE configuration (used when receiving this candidate configuration) or a completed candidate configuration.

[0101] In some example implementations, the UE performs at least one of the following operations to manage the candidate cell configuration: • If there is no separate reference configuration, the candidate delta configuration will be applied over the current UE configuration (used when receiving this candidate configuration) to form a complete candidate configuration. Petition 870250089607, dated 02 / 10 / 2025, pp. 53 / 74 36 / 40 • If a separate reference configuration exists, the candidate delta configuration will be applied over the reference configuration to form a complete candidate configuration. • It is up to the UE to implement the completed candidate configuration, for example, upon receiving the candidate cell configuration or when triggering the mobility execution (e.g., upon receiving the LTM exchange command in the case of LTM, upon meeting the candidate cell execution condition in the case of selective activation of CHO / CPAC / SCG, etc.). • Once the candidate configuration is complete, the UE stores the generated candidate cell configuration for subsequent mobility. • The completed candidate configuration is applied, replacing the current UE configuration (at the time of cell reconfiguration / swap) via an RRCReconfiguration procedure that performs configuration replacements. For LTM, the replacement procedure may not necessarily reset MAC, RLC, or PDCP.

[0102] When candidate configuration formation is complete: • For Need R lEs, only if the parameters are included in the candidate delta configuration, the UE should include them in the completed candidate configuration. • For Need N lEs, if the parameters are included in the ToAddModList in the reference configuration and are not included in the ToReleaseList in the candidate delta configuration, or if the parameters are included in the ToAddModList in the candidate delta configuration, the UE must include them in the ToAddModList in the completed candidate configuration, i.e., there is no ToReleaseList in the completed candidate configuration. • For Need M lEs, if the parameters are included in Petition 870250089607, dated 02 / 10 / 2025, pp. 54 / 74 37 / 40 reference configuration or in the candidate delta configuration, the EU must include them in the completed candidate configuration. When applying the completed candidate configuration and replacing the current UE configuration, the UE can perform at least one of the following actions: • First, discard / release all current dedicated radio configurations, except for some specific fields (e.g., RLC carriers, radio carriers), but keep the current MAC, RLC, and PDCP entities, for example, store state variables and data stored in transmit and receive buffers; • Apply the fields in the completed candidate configuration according to the operation defined in section 5.3.5.3; • Determine whether or not to reset MAC / RLC / PDCP based on the RRC configuration (e.g., cell set) for the target candidate cell; for example, for LTM, if the candidate cell and the source cell belong to the same cell set, resetting MAC / RLC / PDCP may not be necessary; or • When applying the fields in the completed candidate configuration, release the RLC carriers / radio carriers if they are not included in the ToAddModList in the completed candidate configuration.

[0103] In some example implementations, the UE performs a conformance check on the reference configuration upon receiving the reference configuration. If the UE detects a failure in the conformance check on the reference configuration, it can report the failure to the network via a UL message such as, for example, the RRCReconfigurationComplete message. The UE can also discard the reference configuration.

[0104] In some example implementations, it is up to the UE to implement it when performing the compliance check for Petition 870250089607, dated 02 / 10 / 2025, pp. 55 / 74 38 / 40 the candidate cell configuration, for example, when forming the completed candidate configuration, receiving the candidate cell configuration, or triggering the mobility execution.

[0105] The description and accompanying drawings above provide specific examples of embodiments and implementations. The subject described may, however, be materialized in a variety of different forms and, therefore, the subject covered or claimed should be interpreted as not being limited to any exemplary embodiments provided herein. A reasonably broad scope is intended for the subject claimed or covered. Among other things, for example, the subject may be materialized as computer-readable non-transient methods, devices, components, systems, or means for storing computer code. Consequently, embodiments may, for example, take the form of hardware, software, firmware, storage media, or any combination thereof.For example, the method modalities described above can be implemented by components, devices, or systems, including memory and processors, through the execution of computer code stored in memory.

[0106] Throughout the descriptive report and claims, terms may have different meanings, suggested or implied in the context, in addition to an explicitly stated meaning. Similarly, the expression "in one embodiment / implementation," as used herein, does not necessarily refer to the same embodiment, and the expression "in another embodiment / implementation," as used herein, does not necessarily refer to a different embodiment. For example, the claimed subject matter is intended to include combinations of exemplary embodiments, in whole or in part.

[0107] In general, the terminology can be understood, at least in Petition 870250089607, dated 02 / 10 / 2025, pp. 56 / 7439 / 40 part, from the context of use. For example, terms such as and, or, or and / or, as used herein, may include a variety of meanings that may depend, at least in part, on the context in which such terms are used. Typically, or, if used to associate a list, such as A, B, or C, is intended to mean A, B, and C, used herein in an inclusive sense, as well as A, B, or C, used herein in an exclusive sense. Furthermore, the terms one or more or at least one, as used herein depending, at least in part, on the context, may be used to describe any feature, structure, or resource in an individual sense or may be used to describe combinations of features, structures, or resources in a plural sense.Similarly, terms such as a, an, or the, again, can be understood to convey an individual use or to convey a plural use depending, at least in part, on the context. Furthermore, terms based on or determined by can be understood as not necessarily intended to convey an exclusive set of factors and may instead allow for the existence of additional factors not necessarily expressly described, depending, once again, at least in part, on the context.

[0108] Reference to features, advantages, or similar language throughout this descriptive report does not imply that all features and advantages that can be obtained with the present solution must be or are included in any individual implementation thereof. Instead, wording referring to features and advantages should be understood to mean that a specific feature, advantage, or resource described in relation to one embodiment is included in at least one embodiment of the present solution. Petition 870250089607, dated 02 / 10 / 2025, p. 57 / 74 40 / 40 tion. Thus, discussions about the characteristics and advantages, and similar wording, throughout this descriptive report may, but do not necessarily, refer to the same modality.

[0109] Furthermore, the features, advantages, and resources described in the present solution can be combined in any suitable manner in one or more embodiments. A professional with average knowledge in the relevant area will recognize, in light of the description presented in this document, that the present solution can be implemented without one or more of the specific features or advantages of a particular embodiment. In other cases, additional features and advantages may be recognized in certain embodiments which may not be present in all embodiments of the present solution.

Claims

1. A method for selective activation of cell groups performed by a primary node (MN), characterized in that it comprises: sending a request message to a candidate secondary node (SN) to request preparation of a selective cell group activation procedure for a wireless terminal; receiving a confirmation message from the candidate SN in response to the request message, the confirmation message comprising a first list of cell identifiers for a set of candidate cells; and sending a reconfiguration message to the wireless terminal, the reconfiguration message comprising a selective cell group activation configuration; and wherein the selective cell group activation procedure comprises a subsequent conditional addition / swap of PSCell (CPAC) procedure and wherein the selective cell group activation configuration comprises a subsequent CPAC configuration.

2. A method according to claim 1, characterized in that the confirmation message comprises, for each of the set of candidate cells, at least one of the following: a cell identifier, a candidate configuration of PSCell or Secondary Cell Group (SCG), a list of subsequent candidate PSCells suggested for a subsequent conditional cell exchange (CPC); or execution conditions for each of the subsequent candidate PSCells suggested.

3. Method, according to claim 1, characterized in that the request message comprises at least one of the following: Petition 870250089607, dated 10 / 02 / 2025, page 67 / 74 2 / 7 a list of suggested SN identifiers or candidate cell for subsequent CPC; a list of SN keys to be used for the next / subsequent CPC; or a list of counter values ​​to be used for deriving SN keys for the next / subsequent CPC.

4. Method according to claim 2, characterized in that: the request message comprises an indication to the candidate SN that the candidate SN is permitted to suggest subsequent candidate cells for subsequent CPC; and the request message is received by the candidate SN to trigger the SN to perform at least one of the following: identify the set of candidate cells; identify the list of suggested subsequent candidate PSCells that correspond to each of the set of candidate cells suggested by the MN, if included in the request message; and determine the execution conditions for each of the suggested subsequent candidate PSCells in the list.

5. Method according to claim 1, characterized in that the subsequent CPAC procedure is initiated by the MN.

6. Method according to claim 1, characterized in that the subsequent CPAC procedure is initiated by a source SN in communication with the wireless terminal.

7. Method, according to claim 6, characterized in that it further comprises, before sending the request message to the candidate SN, receiving a required SN exchange message from the source SN.

8. Method, according to claim 7, characterized in that the required SN exchange message comprises at least one of the following: an indication to the MN that the required SN exchange is for the selective activation procedure of the cell group; a list of suggested candidate SN or cell identifiers for subsequent CPC; or an SCG reference configuration.

9. A method according to claim 1, characterized in that sending the reconfiguration message comprises: receiving a second confirmation message from at least one other candidate SN; and sending the reconfiguration message, the reconfiguration message being based on the confirmation message and the second confirmation message.

10. Method according to claim 2, characterized in that it further comprises transmitting the report to the candidate SN to inform the candidate SN of a subset of the list of subsequent candidate PSCells suggested for subsequent CPC, the subset of the list of subsequent candidate PSCells suggested being included in the reconfiguration message to the wireless terminal.

11. Method according to claim 1, characterized in that it further comprises receiving, from the wireless terminal, a completed reconfiguration message, the completed reconfiguration message comprising information to identify a target SN selected by the wireless terminal.

12. Method according to claim 11, characterized in that it further comprises sending a completed reconfiguration message from the SN to the target SN.

13. Method, according to claim 11, characterized in that it further comprises sending a report message to a source SN connected to the wireless terminal, the report message instructing the source SN to maintain or release a wireless terminal context or to discard / release / update a current SN key.

14. Method according to claim 12, characterized in that it further comprises sending a report message to each of the other candidate SNs, the report message indicating to each of the other candidate SNs to maintain or release a list of candidate cells prepared for the selective cell group activation procedure or to discard / release / update a candidate SN key.

15. A method according to claim 1, characterized in that the subsequent CPAC configuration comprises at least one of: a list of prepared candidate cells; execution conditions for each of the prepared candidate cells in the list; a list of subsequent prepared candidate cells for each of the prepared candidate cells in the list; and execution conditions for each of the subsequent prepared candidate cells in the list.

16. Method for selective activation of cell groups performed by a candidate secondary node (SN), characterized in that it comprises: receiving a request message from a primary node (MN) of a wireless terminal to request the preparation of a selective cell group activation procedure for the wireless terminal; preparing a first list of cell identifiers for a set of candidate cells; and sending a confirmation message to the MN, the confirmation message comprising the first list of cell identifiers for the set of candidate cells, wherein the selective cell group activation procedure comprises a subsequent conditional addition / exchange procedure of PSCell (CPAC).

17. A method according to claim 16, characterized in that it further comprises preparing, for each of the sets of candidate cells, a list of suggested subsequent candidate PSCells for a subsequent conditional cell exchange (CPC), wherein the confirmation message comprises, for each of the candidate cells in the set, at least one of the following: a cell identifier, the list of suggested subsequent candidate PSCells, or execution conditions for each of the suggested candidate PSCells.

18. Method, according to claim 16, characterized in that the request message comprises at least one of the following: a list of suggested candidate SN or cell identifiers for subsequent CPC; a list of SN keys to be used for the next / subsequent CPC; or a list of counter values ​​to be used for SN key derivation for the next / subsequent CPC.

19. Method according to claim 17, characterized in that it further comprises receiving a report from the MN, the report informing the candidate SN of a subset of the list of subsequent candidate PSCells suggested for subsequent CPC, the subset of the list of subsequent candidate PSCells suggested being included in a reconfiguration message sent from the MN to the wireless terminal. Petition 870250089607, dated 10 / 02 / 2025, pp. 71 / 74 6 / 7 20. A primary node (MN) comprising at least one processor and one memory, characterized in that at least one processor is configured to read a code from memory to: send a request message to a candidate secondary node (SN) to request preparation of a selective cell group activation procedure for a wireless terminal; receive a confirmation message from the candidate SN in response to the request message, the confirmation message comprising a first list of cell identifiers for a set of candidate cells;and send a reconfiguration message to the wireless terminal, the reconfiguration message comprising a selective cell group activation configuration, wherein the selective cell group activation procedure comprises a subsequent conditional addition / swap of PSCell (CPAC) procedure, and wherein the selective cell group activation configuration comprises a subsequent CPAC configuration.

21. A method for a conditional handover (CHO) procedure, executed by a source principal node (MN), characterized in that it comprises: sending a handover request message to a candidate MN to cause the candidate MN to initiate a candidate secondary node (SN) and a candidate PSCell preparation for the CHO procedure; and receiving a handover request confirmation message from the candidate MN to provide information about the candidate cell for the CHO procedure.

22. Method for a Conditional Handover Procedure (CHO), performed by a candidate principal node (MN), characterized in that it comprises: receiving a handover request message from a source MN; initiating a candidate secondary node (SN) and a candidate PSCell preparation for the CHO procedure with one or more candidate SNs; and transmitting a handover request confirmation message to the source MN to provide information about the candidate cell for the CHO procedure.

23. A method according to claim 21 or 22, characterized in that the handover request message comprises at least: an ID of a requested candidate cell; and an indication to show that the handover request message is for CHO with candidate secondary cell groups (SCGs).

24. A method according to claim 23, characterized in that the handover request confirmation message comprises at least: a cell configuration for the requested candidate cell and a candidate PSCell; ID(s) of one or more candidate PSCells associated with the requested candidate cell; and execution conditions for one or more candidate PSCells.

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