Method for selectively activating cell groups

Abstract

The present disclosure relates generally to wireless communications and, more particularly, to enhanced processing of wireless terminal mobility through successive / subsequent conditional cell changes. Various example embodiments are provided to describe example ways for preparing candidate SCG / PSCell configurations for SCG selective activation to support subsequent conditional PSCell addition / change between various network elements, including indicating available / subsequent candidate PSCell of all candidate PSCells to be evaluated when the candidate PSCell becomes a serving PSCell during UE mobility.

Description

Technical Field

[0001] This disclosure generally relates to wireless communications, and more specifically, to enhancement processing of wireless terminal mobility through continuous / subsequent conditional cell changes. Background Technology

[0002] Wireless communication technology is driving the world toward ever-growing network connectivity. Wireless communication relies on efficient network resource management and allocation between users and radio access network nodes (including but not limited to radio base stations) in highly mobile environments. Next-generation networks are expected to provide high-speed, low-latency, and ultra-reliable communication capabilities to meet the requirements of diverse industries and users. User mobile stations or user equipment (UEs) are becoming increasingly complex to handle ever-increasing data traffic. To improve communication and meet higher reliability requirements, enhanced mobility management is crucial. Summary of the Invention

[0003] This disclosure generally relates to wireless communications, and more specifically, to enhanced processing of wireless terminal mobility through successive / subsequent conditional cell changes. Various example implementations are provided to describe exemplary methods for preparing candidate SCG / PSCell configurations for selective SCG activation to support subsequent conditional PSCell additions / changes among various network elements, including indicating available / subsequent candidate PSCells among all candidate PSCells to be evaluated when a candidate PSCell becomes the serving PSCell during UE mobility.

[0004] In some implementations, a method is performed for selectively activating a cell group for a wireless terminal in a wireless network, and is executed by a master node (MN). The method may include sending a request message to a candidate secondary node (SN) to request preparation for a cell group selective activation process for the wireless terminal; receiving an acknowledgment message from the candidate SN in response to the request message, the acknowledgment message including a first list of cell identifiers for a group of candidate cells; generating a reconfiguration message based on the acknowledgment message, the reconfiguration message including a cell group selective activation configuration; and sending the reconfiguration message to the wireless terminal.

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

[0006] In any of the above example implementations, the request message includes at least one of the following: an indication to a candidate SN that the candidate SN is permitted to be suggested as a subsequent candidate cell for the next / subsequent CPC of the wireless terminal; a list of suggested candidate SNs or cell identifiers for the next / subsequent CPC; an upper limit on the number of subsequent candidate cells that can be prepared for the next / subsequent CPC for each candidate cell; a list or range of SN keys for the next / subsequent CPC; or a counter value or a list of counter values ​​for the SN key derivation for the next / subsequent CPC.

[0007] In any of the above example implementations, the request message includes an indication to the candidate SN that the candidate SN is permitted to suggest subsequent candidate cells for the next / subsequent CPC; and the request message is received by the candidate SN to trigger the SN to perform at least one of the following operations: identifying a set of candidate cells; if the request message includes an MN suggestion, identifying a second list of candidate SNs or cells corresponding to one of the candidate cells from the MN suggestion; and determining the execution conditions for each of the second list of candidate SNs or cells based on the candidate cell measurement configuration.

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

[0009] In any of the above example implementations, selective activation of a cell group is initiated by a source SN communicating with the radio terminal. The method may further include receiving an SN change request message from the source SN before sending a request message to a candidate SN. The SN change request message includes at least one of the following: an indication to the MN indicating that the candidate SN is permitted to suggest subsequent candidate cells for the radio terminal's next / subsequent CPC; a list of suggested candidate SNs or cell identifiers for the next / subsequent CPC; or an upper limit on the number of subsequent candidate cells that the candidate SN may prepare for each candidate cell's next / subsequent CPC.

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

[0011] In any of the above example implementations, the method may further include generating a report and sending the report to a candidate SN to notify the candidate SN of a subset of subsequent candidates for conditional cell changes included in a reconfiguration message to a radio terminal.

[0012] In any of the above example embodiments, the method may further include receiving a reconfiguration complete message from the wireless terminal in response to a reconfiguration message, the reconfiguration complete information including information for identifying the target SN selected by the wireless terminal. The method may further include sending an SN reconfiguration complete message to the target SN.

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

[0014] In any of the above example implementations, the method may further include sending a report message to each of the other candidate SNs, the report message instructing each of the other candidate SNs to retain or release a list of candidate cells prepared for a cell group selective activation process, or to discard / release / update a candidate SN key.

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

[0016] In some other example implementations, a method is disclosed for selectively activating a cell group for a wireless terminal in a wireless network, performed by a candidate SN. The method may include receiving a request message from the master node (MN) of the wireless terminal to request preparation for a cell group selective activation process for the wireless terminal; preparing a first list of cell identifiers for a set of candidate cells; and sending an acknowledgment message to the MN, the acknowledgment message including the first list of cell identifiers.

[0017] In the above example implementation, the method may further include preparing a second list of candidate SNs or cells corresponding to one of the candidate cells in a set of candidate cells. The second list of candidate SNs or cells includes subsequent candidates for conditional cell change (CPC) when one of the candidate cells in the set of candidate cells becomes the current serving cell of the wireless terminal. The confirmation message also includes the second list of candidate SNs or cells corresponding to one of the candidate cells in the set of candidate cells.

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

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

[0020] In some other embodiments, a wireless communication device is disclosed. This wireless communication device may include a processor and a memory, wherein the processor is configured to read computer code from the memory to implement any of the methods described above.

[0021] In some other embodiments, a non-transitory computer-readable medium is disclosed. The non-transitory computer-readable medium may include computer instructions that, when executed by a processor of a wireless communication device, cause the wireless communication device to perform any of the methods described above. Attached Figure Description

[0022] Figure 1 An example wireless communication network including a wireless access network, a core network, and a data network is shown.

[0023] Figure 2 An example radio access network is shown, comprising multiple mobile stations / terminals or user equipment (UE) and radio access network nodes communicating with each other via an over-the-air wireless communication interface.

[0024] Figure 3 An example radio access network (RAN) architecture is shown.

[0025] Figure 4 An example communication protocol stack is shown in a wireless access network node or wireless terminal device that includes various network layers.

[0026] Figure 5 The basic scenario of SN change is shown.

[0027] Figure 6 The candidate secondary cell groups for subsequent conditional PSCell additions / changes are shown.

[0028] Figure 7Example data and logical flows between various network elements used for selective secondary cell group activation are shown.

[0029] Figure 8 Another example of data and logic flow between various network elements used for selective secondary cell group activation is shown. Detailed Implementation

[0030] The present disclosure will now be described in detail below with reference to the accompanying drawings, which form a part of this disclosure, and the drawings illustrate specific examples of embodiments by way of illustration. However, it should be noted that the present disclosure may be embodied in various different forms, and therefore, the subject matter covered or claimed is intended to be construed as not being limited to any of the embodiments set forth below.

[0031] Throughout the specification and claims, terms may have subtle meanings implied or implied in the context that go beyond their explicitly stated meaning. Similarly, the phrases “in one embodiment” or “in some embodiments” as used herein do not necessarily refer to the same embodiment, and the phrases “in another embodiment” or “in other embodiments” as used herein do not necessarily refer to different embodiments. For example, it is intended that the claimed subject matter encompasses all or part of the exemplary embodiments or combinations of embodiments.

[0032] Generally, terms can be understood at least in part from their usage in the context. For example, terms such as “and,” “or,” or “and / or” as used herein can include a variety of meanings, which depend at least in part on the context in which they are used. Typically, “or” means A, B, and C when used in an associative list, such as A, B, or C, in an inclusive sense, and A, B, or C in an exclusive sense. Additionally, the terms “one or more” or “at least one” as used herein depend at least in part on the context and can be used to describe any feature, structure, or characteristic in a singular sense, or can be used to describe a combination of features, structures, or characteristics in a plural sense. Similarly, terms such as “a,” “an,” or “the” can also be understood to indicate singular or plural usage, at least in part on the context. Furthermore, the terms “based on…” or “determined by…” can be understood not necessarily to express a set of exclusive factors, and instead allow for additional factors that are not necessarily explicitly described, at least in part on the context.

[0033] Wireless Network Overview

[0034] Figure 1The example wireless communication network, shown as 100, may include wireless terminal equipment or user equipment (UE) 110, 111, and 112, carrier network 102, various service applications 140, and other data networks 150. The wireless terminal equipment or UE may alternatively be referred to as a wireless terminal. Carrier network 102 may, for example, include access network nodes 120 and 121 and core network 130. Bearer network 110 may be configured to transmit voice, data, and other information (collectively referred to as data services) 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 may be configured as various radio access network nodes (WANNs, alternatively referred to as wireless base stations) to interact with the UE on one side of a communication session and the core network 130 on the other side. The term "access network" may be used more broadly to refer to the combination of wireless terminal equipment 110, 111, and 112 with access network nodes 120 and 121. The radio access network may alternatively be referred to as a radio access network (RAN). The core network 130 may include various network nodes configured to control communication sessions and perform network access management and service routing. Service applications 140 may be hosted by various 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.

[0035] exist Figure 1 In the example wireless communication network 100, UEs can communicate with each other through a wireless access network. For example, UEs 110 and 112 can be connected to the same access network node 120 and communicate through that node 120. UEs can communicate with each other through both the access network and the core network. For example, UE 110 can be connected to access network node 120, while UE 111 can be connected to access network node 121, and therefore UEs 110 and UE 111 can communicate with each other through access network nodes 120 and 121 and the core network 130. UEs can also communicate with the serving application 140 and the data network 150 through the core network 130. Furthermore, UEs can communicate directly with each other through sidelink communication, as shown in 113.

[0036] Figure 2An example system diagram of a radio access network 120, including a WANN 202 providing services to UEs 110 and 112 via air interface 204, is also shown. The radio transmission resources of air interface 204 include a combination of frequency, time, and / or spatial resources. Each of UEs 110 and 112 can be a mobile or fixed terminal device equipped with a mobile access unit (such as a SIM / USIM module) for accessing the wireless communication network 100. UEs 110 and 112 can each be implemented as terminal devices, including but not limited to mobile phones, smartphones, tablets, laptops, in-vehicle communication equipment, roadside communication equipment, sensor equipment, smart appliances (such as televisions, refrigerators, and ovens), or other devices capable of wireless communication over a network. Figure 2 As shown, each UE, such as UE 112, may include transceiver circuitry 206 coupled to one or more antennas 208 to enable wireless communication with WANN 120 or with another UE, such as UE 110. Transceiver circuitry 206 may also be coupled to processor 210, which may also be coupled to memory 212 or other storage devices. Memory 212 may be transient or non-transient and may store computer instructions or code therein that, when read and executed by processor 210, cause processor 210 to implement the various methods described herein.

[0037] Similarly, WANN 120 may include a wireless base station or other wireless network access point capable of wirelessly communicating with one or more UEs and the core network 130 via air interface 204. For example, WANN 120 may be implemented without limitation as a 2G base station, 3G Node B, LTE eNB, 4G LTE base station, 5G NR base station of 5G gNB, 5G central unit base station, or 5G distributed unit base station. Each type of WANN can be configured to perform the corresponding set of wireless network functions. WANN 202 may include transceiver circuitry 214 coupled to one or more antennas 216, which may include various forms of antenna towers 218 to enable wireless communication with UEs 110 and 112. Transceiver circuitry 214 may be coupled to one or more processors 220, which may also be coupled to memory 222 or other storage devices. The memory 222 may be transient or non-transient and may store instructions or code therein that, when read and executed by one or more processors 220, cause one or more processors 220 to perform the various functions of the WANN 120 described herein.

[0038] Such as Figure 2Data packets in the example wireless access network described herein can be transmitted as Protocol Data Units (PDUs). The data contained herein can be packaged into PDUs at various network layers, wrapped with nested and / or layered protocol headers. Once a connection is established between the transmitter and receiver (e.g., a Radio Link Control (RRC) connection), the PDUs can communicate between the transmitting device or transmitter (these two terms can be used interchangeably) and the receiving device or receiver (these two terms can also be used interchangeably). Either the transmitting device or the receiving device can be a wireless terminal device, such as... Figure 2 The devices 110 and 120 can also be wireless access network nodes, such as... Figure 2 Node 202 in the diagram. Each device can be both a transmitting and receiving device for bidirectional communication.

[0039] Figure 1 The core network 130 may include various geographically distributed and interconnected network nodes to provide network coverage to the service area of ​​the carrier 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 software entities. Each of these network nodes may be configured with one or more types of network functions, which together provide provisioning and routing capabilities for the core network 130.

[0040] Returning to the Radio Access Network (RAN). Figure 3 An example RAN 340 communicating with core network 310 and radio terminals UE1 through UE7 is shown. RAN 340 may include one or more radio base stations or WANNs 320 and 321 of various types, which may include, but are not limited to, gNBs, eNodeBs, NodeBs, or other types of base stations. RAN 340 may be backhauled to core network 310. WANN 320 may also include, for example, multiple individual access network nodes in the form of a central unit (CU) 322 and one or more distributed units (DUs) 324 and 326. CU 322 is connected to DU1 324 and DU2 326 via various interfaces (e.g., F1 interfaces). The F1 interface may also include, for example, an F1-C interface and an F1-U interface, which may be used to carry control plane information 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). While the various implementations described below are provided in the context of 5G cellular wireless networks, the basic principles described herein are applicable to other types of wireless access networks, including but not limited to other generations of cellular networks, as well as Wi-Fi, Bluetooth, ZigBee, and WiMax networks.

[0041] The UE can be connected to the network via the WANN 320 through the air interface. The UE can be served by at least one cell. Each cell is associated with a coverage area. These cells can also be alternatively referred to as serving cells. The coverage areas between cells can partially overlap. Each UE can actively communicate with at least one cell and can potentially connect to or be connected to more than one cell. Figure 1 In the example, UE1, UE2, and UE3 can be served by cell 1 330 of DU1, while UE4 and UE5 can be served by cell 2 332 of DU1, and UE6 and UE7 can be served by cell 3 associated with DU2. In some implementations, a UE can be served by two or more cells simultaneously. Each UE can be mobile, and the signal strength and quality from the individual cells at the UE's location can depend on the UE's location and mobility.

[0042] Figure 4 Further demonstrated in Figures 1 to 3 A simplified view of the various network layers involved in transmitting user plane PDUs from transmitting device 402 to receiving device 404 in an example wireless access network. Figure 4 It is not intended to include all the basic equipment components or network layers used to process PDU transmissions. Figure 4 This illustrates how data packaged by the upper network layer 420 at the transmitting device 402 can be sent to the corresponding upper layer 430 (such as the Radio Resource Control or RRC layer) at the receiving device 304 in the following manner: the packet data convergence protocol layer (PDCP layer) of the transmitting device. Figure 4 The network consists of a wireless link control (RLC) layer 422 (not shown), a physical (PHY) layer for transmitting and receiving devices, a wireless interface (as shown in 406), and a media access control (MAC) layer 434 and an RLC layer 432 for receiving devices. Various network entities within each of these layers can be configured to handle the transmission and retransmission of PDUs.

[0043] exist Figure 4 In the middle, the upper layer 420 can be referred to as layer 3 or L3, while layers such as RLC layer and / or MAC layer and / or PDCP layer ( Figure 4Intermediate layers (not shown in the diagram) 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 radio interface-related layers. In some cases, the term "lower layer" can be used to refer to the set of L1 and L2, while the term "higher layer" can be used to refer to Layer 3. In some cases, the term "lower layer" can be used to refer to layers below the current reference layer among L1, L2, and L3. Control signaling can be initiated and triggered in each of the layers from L1 to L3 and within each of the network layers therein. These signaling messages can be encapsulated and concatenated into lower-layer encapsulations and transmitted through allocated control or data air radio resources and interfaces. The term "layer" typically includes its various corresponding entities. For example, the MAC layer encompasses the corresponding MAC entity that can be created. Layer 1, for example, encompasses the PHY entity. As another example, Layer 2 encompasses the MAC layer / entity, RLC layer / entity, Serving Data Adaptation Protocol (SDAP) layer, and / or PDCP layer / entity.

[0044] Conditional PSCell Addition / Change (CPAC)

[0045] A UE in a wireless network can be configured to operate in dual connectivity, including E-UTRA in-DC or multiple radio DC (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 (RATs). For example, in the case of an E-UTRA in-DC, both the MN and SN provide E-UTRA access. In the case of an MR-DC, one node provides NR access, and the other node provides either E-UTRA or NR access.

[0046] One or more serving cells can be configured on both the MN and SN. Serving cells configured on the MN are defined as a primary cell group (MCG), while serving cells configured on the SN are defined as a secondary cell group (SCG). Within each type of cell group, there can be one primary cell and one or more secondary cells. For example, a primary cell in an MSG can be called a PCell, while a primary cell in an SCG can be called a PScell. Secondary cells in either an MCG or an SCG can be called SCells. Primary cells, including PCells and PScells, can be collectively referred to as spCells (special cells). All these cells can be referred to as serving cells or simply cells. Unless otherwise specified, the terms "cell" and "serving cell" are generally used interchangeably. The term "serving cell" can refer to a cell that is currently serving the UE, will serve the UE, or can serve the UE. In other words, a "serving cell" may not currently be providing service to the UE. While the various embodiments described below may sometimes relate to one of the above-described serving cell types, the basic principles apply to all types of serving cells within both types of serving cell groups.

[0047] Figure 5 This illustrates one possible scenario for SN changes. Figure 5 Three example network nodes (e.g., base stations) are shown, including MN (502), SN1 (504), and SN2 (506). Cell 1, Cell 2, and Cell 3 are example corresponding cells generated by MN, SN1, and SN2, respectively. Cell 2 and Cell 3 are special cells of the Secondary Cell Group (SCG) and are defined as primary SCG cells (PSCell). The X interface is deployed between MN and SN1 / SN2. At time T1, the UE can operate under DC between MN and SN1. As the UE moves, at time T2, the SN used for the UE can be switched from SN1 to SN2. Such SN changes can be initiated by MN or the source SN (e.g., SN1).

[0048] In some cases, 5G networks with small cells may experience very frequent cell handovers or SN changes. To reduce downtime and improve mobility reliability (i.e., mobility robustness), Conditional PSCell Addition / Change (CPAC) can be implemented. CPAC can be defined as a PSCell addition / change performed by the UE when one or more execution conditions are met. The UE can begin evaluating one or more execution conditions after receiving the CPAC configuration and can stop evaluating one or more execution conditions after the PSCell addition / change is triggered. The CPAC configuration may, for example, include candidate PSCell configurations (including SCG configurations generated by one or more candidate SNs and MCG configurations possibly generated by the MN) and one or more corresponding execution conditions for the candidate PSCells.

[0049] A CPAC procedure can be triggered by either an MN or a SN, and therefore can be classified as an MN-initiated CPAC or an SN-initiated CPAC. In addition, a CPAC procedure can be initiated by an MN or not, and therefore can also be classified as a CPAC with MN participation or a CPAC without MN participation (i.e., a CPC (Conditional PSCell Change) within an SN without MN participation).

[0050] For CPA / CPC initiated by MN, the execution conditions can be generated by MN based on MCG MeasConfig, such as event A4. For CPC initiated by SN, the execution conditions can be generated by the source SN based on SCG MeasConfig, such as events A3 / A5. Events A3, A4, and A5 can be defined as occurring in the following ways:

[0051] Event A3: The measurement signal of the neighboring cell becomes superior to PCell / PSCell by a certain offset;

[0052] Event A4: The measurement signal of the neighboring cell becomes better than the absolute threshold;

[0053] Event A5: PCell / PSCell becomes worse than absolute threshold 1, and neighboring cells / SCell become better than another absolute threshold 2;

[0054] Selective activation of cell groups (CGs)

[0055] For selective activation of cell group (CG) changes, the NW can pre-configure multiple candidate CG configurations and send them to the UE. The UE stores multiple candidate CG configurations. The UE can then perform CG changes among the candidate CGs based on NW indications / signaling (e.g., RRC messages, MAC CE) or pre-configured execution conditions.

[0056] For simplicity, in the following disclosure, the term "candidate cell" may be referred to alternatively as "candidate cell group (CG)". CG may be used to represent one or both of MCG or SCG. The term candidate cell may be referred to as candidate PCell in MCG or candidate PSCell in SCG.

[0057] For MCG / PCell changes, the term "selective activation of CG change" can be referred to as subsequent / continuous conditional switching (CHO), or selective activation of MCG / PCcell, selective activation of MCG / PCCell, conditional selective MCG / PCell, etc. Similarly, for SCG / PSCell changes, the term "selective activation of CG change" can be referred to as subsequent / continuous conditional PSCell change (CPC), subsequent / continuous conditional PSCell addition (CPA), selective activation of SCG / PSCell, selective activation of SCG / PSCell, conditional selective SCG / PSCell, etc.

[0058] In some of the implementations disclosed below, SCG / PSCell changes (e.g., CPC) can be described as examples. The basic principles and related solutions also apply to MCG / PCell changes.

[0059] The example baseline procedure that supports subsequent PSCell / SCG changes is shown below:

[0060] The NW sends multiple candidate PSCell / SCG configurations and execution conditions for the candidate PSCell / SCGs to the UE.

[0061] The UE stores multiple candidate PSCell / SCG configurations and evaluates the execution conditions of the candidate PSCell / SCG. When the execution conditions of a candidate PSCell / SCG are met, the UE performs CPA or CPC on that candidate PSCell.

[0062] After completing the addition or modification of a PSCell, the UE may not release the conditional configurations of other candidate PSCells used for subsequent CPCs, and may continue to evaluate the execution conditions of other candidate PSCells.

[0063] When the execution conditions of a candidate PSCell are met, the UE then performs subsequent CPCs on that candidate PSCell.

[0064] To support subsequent CPAC, candidate SCG / PSCell configurations need to be retained after an SCG is added or changed (e.g., CPA / CPC or normal conditional PSCell addition / change). When a UE moves to a specific candidate SCG / PSCell, some other candidate SCG / PSCells may not be suitable as candidates for the next SCG / PSCell change (e.g., the next CPC execution). For example, as... Figure 6 As shown, there are 7 candidate SCGs pre-configured by the NW for subsequent CPAC changes. When the UE moves to SCG_3, the neighboring SCG_2, SCG_4, and SCG_5 can be candidate SCGs for the next SCG change. However, other SCGs (such as SCG_1, SCG_6, and SCG_7) may not be suitable for the next SCG change. Therefore, the NW can also indicate which candidate SCGs are available for subsequent SCG changes for each candidate SCG. When the UE moves to a specific SCG, it only needs to evaluate the execution conditions of these available candidate SCGs to avoid unnecessarily evaluating other candidates and avoiding frequent updates of candidates via RRCReconfiguration (e.g., releasing some candidates and adding them again). In other words, the UE can retain the configuration of all candidate SCGs / PSCells, but only needs to monitor and evaluate a subset of SCGs / PSCells for subsequent SCG / PSCell changes. The subset of SCGs / PSCells is indicated by the NW.

[0065] Various example implementations are provided to describe example ways of preparing candidate SCG / PSCell configurations for selective activation of SCG (i.e., supporting subsequent CPAC) among various network elements, including indicating available / subsequent candidate PSCells among all candidate PSCells to be evaluated when a candidate PSCell becomes a serving PSCell during UE mobility.

[0066] Example process and signaling for selective activation of SCG

[0067] Figure 7 Example data and logic flow 700 for selective SCG activation are shown. Selective SCG activation can be initiated by the MN. Figure 7 Example data and logic flows may include the following information exchange between UE 702, MN 704, source SN 706, candidate SN 708, and 710:

[0068] Step 1 The MN sends an SN Add Request message to the set of candidate SNs, for example, candidate SN 708 and another candidate SN 710 (only one of these candidates is tracked below), to request preparation / initiation of the SCG selective activation process. This message may include at least one of the following:

[0069] The upper limit on the number of PSCells (candidate PSCells) that can be prepared from candidate SNs;

[0070] Measurements related to candidate SNs;

[0071] A list of proposed PSCell candidates based on the source SN's suggestion, for example, for SN-initiated inter-SN SCG selective activation;

[0072] Refer to the SCG configuration (so that candidate SNs only need to send the differential / incremental (delta) configurations of various candidate SCG configurations);

[0073] This indicates that the request is for selective activation;

[0074] Indicator candidate SN / PSCell can suggest indications for subsequent candidate PSCells for the next / subsequent CPC;

[0075] A list of suggested candidate SN IDs for the next / subsequent CPC;

[0076] A suggested list of subsequent candidate PSCells for the next / subsequent CPC;

[0077] For each candidate PSCell prepared by the candidate SN, there is an upper limit to the number of PSCells that can be prepared for the next / subsequent CPC.

[0078] A list or range of SN keys for the next / subsequent CPC;

[0079] Counter values ​​or a list of counter values ​​used for SN key derivation in the next / subsequent CPC;

[0080] 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 candidate SN determines a list of one or more PSCells to prepare (i.e., the initially prepared candidate PSCells) and provides a candidate PSCell / SCG configuration (e.g., based on a reference SCG configuration, such as a differential / incremental candidate PSCell configuration) for each prepared candidate PSCell. If an indication that the request is for selective activation or an indication that a candidate SN / PSCell can suggest / select a subsequent candidate PSCell for the next / subsequent CPC is received, then for each initially prepared candidate PSCell, the candidate SN determines / suggests / selects a subsequent candidate SN and / or the subsequent candidate PSCell of that prepared candidate PSCell. If the MN provides a list of suggested subsequent candidate SN IDs and / or subsequent candidate PSCells for the next / subsequent CPC, the candidate SN selects a subsequent candidate SN and / or PSCell from the list provided by the MN. Candidate SNs can also provide execution conditions for each subsequent candidate PSCell used in the next / subsequent CPC (e.g., execution conditions based on events A3 / A5). Execution conditions can be based on the candidate SCG measurement configuration of the prepared candidate PSCell.

[0081] Step 2 The candidate SN sends an SN add request confirmation message to the MN. This message may include a list of prepared candidate PSCell IDs, and may also include at least one of the following information for each prepared candidate PSCell:

[0082] Candidate PSCell / SCG configurations;

[0083] A list of suggested candidate SNs and / or PSCells for the next / subsequent CPC, such as a list of candidate PSCell IDs (e.g., CGIs);

[0084] Execution conditions for each suggested subsequent candidate PSCell for the next / subsequent CPC;

[0085] Step 3For each prepared candidate PSCell, if it has subsequent candidate PSCells, the MN can check if there is a prepared candidate PSCell configuration for the subsequent candidate PSCell (whose configuration can be generated by other candidate SNs). If a prepared candidate PSCell configuration exists, the MN generates an association between the candidate PSCell configuration and the execution conditions of the subsequent candidate PSCell. If no prepared candidate PSCell configuration exists for the subsequent candidate PSCell, the MN can initiate an SN Add process to the candidate SN to which the candidate PSCell belongs, requesting that SN to provide a candidate PSCell / SCG configuration for the PSCell. If there are subsequent candidate PSCells whose candidate PSCell configuration and / or execution conditions are not ready, the MN can notify the candidate SN. For example, for each prepared candidate PSCell, the MN can notify the candidate SN which subsequent candidate PSCells are ready (e.g., their candidate configuration and associated execution conditions are ready) via an Xn / X2 message (e.g., an SN Modification Request message). This 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 PSC Cells that have been prepared for the next / next CPC.

[0086] Step 4 If requested (e.g., in response to the Xn / X2 message in step 3 above), the candidate SN can send a response message to the MN, such as the SN modification request message.

[0087] In some example implementations, steps 4 and 5 above can also be performed between MN and the source SN, for example, when the source SN is considered a candidate SN.

[0088] Step 5 The MN generates an RRC reconfiguration message that includes the SCG selective activation configuration. The SCG selective activation configuration may include one or more reference configurations and a list of prepared candidate PSCells. For each prepared candidate PSCell, it may include the candidate PSCell ID (e.g., candidate PSCell configuration index, PCI+ frequency), the candidate PSCell / SCG configuration, one or more execution conditions, a list of sk counters or SN keys, and / or information for the next / subsequent CPC. For each prepared candidate PSCell, the next / subsequent CPC information may include a list of subsequent candidate PSCells to be evaluated when the prepared candidate PSCell becomes a serving PSCell (i.e., after it is added or changed to a prepared candidate PSCell), and / or one or more execution conditions for each subsequent candidate PSCell. The MN sends the generated RRC reconfiguration message to the UE.

[0089] Step 6 The UE responds to the MN with an RRC reconfiguration complete message.

[0090] Step 7 The MN notifies the source SN that the SCG selective activation process has been configured / is ready via Xn / X2 messages (e.g., Xn-U Address indication messages). If applicable, the source SN can then begin early data forwarding.

[0091] Step 8 The UE begins evaluating execution conditions. If one or more execution conditions for a candidate PSCell are met, the UE performs a CPAC procedure for the target PSCell. For example, the CPAC procedure may include applying candidate cell configuration for the PSCell and performing random access for the PSCell.

[0092] Step 9 The UE sends an RRCReconfigurationComplete message to the MN. This message may include information that enables the MN to identify the SN of the selected candidate PSCell.

[0093] Step 10 The MN sends an SN Reconfiguration Complete message to the target SN. If a list of SN keys exists, the target SN uses the first SN key in the list for subsequent data transmission with the UE.

[0094] Step 11a / b: The MN sends an Xn / X2 message (e.g., an SN Release Request message, an Xn-U address indication message, or other message) to notify the source SN and / or one or more candidate SNs regarding CPC or CPA execution. This message may include an indication that the procedure is being used for SCG selective 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 a candidate SN, the MN may indicate to the source SN that the UE context in the SN is preserved, for example, via an indication for SCG selective activation or an indication for UE context preservation in the message. If this indication is included, the SN may preserve the UE context. The source SN may discard / release / update the SN key that has been used. Upon receiving the message, the source SN and / or candidate SNs may update the SN key that can be used when the UE switches back to the same SN. Messages to the source or candidate SN may instruct the SN to release or preserve a list of candidate PSCells prepared for SCG selective activation. The source SN and / or candidate SN can send a response message to the MN (e.g., an SN Release Request Acknowledge message).

[0095] Step 12 The UE can synchronize with a selected target PSCell by, for example, performing random access.

[0096] Steps 13a-c: The UE may retain the candidate PSCell configuration and perform an evaluation of the execution conditions for the retained candidate PSCell or the candidate PSCell indicated to perform the execution condition evaluation for the next CPC (if indicated by the NW). If the execution condition of a candidate PSCell is met, the UE performs subsequent CPC execution for the selected target PSCell.

[0097] In some example implementations, such as before step 1, the MN may send a request message (e.g., an SN add or modify request message) to the source SN or candidate SN to request a reference SCG configuration, such as an indication of a reference configuration request. In response to receiving the message or request indication, the source or candidate SN generates the reference SCG configuration and sends it to the MN, for example, via an SN add or modify request message acknowledgment. This reference SCG configuration may be an RRC reconfiguration message generated by the SN.

[0098] In some example implementations, the MN may send the candidate PSCell configuration index of each initially prepared candidate PSCell to the candidate SN. The candidate SN may then associate the candidate PSCell configuration index with the corresponding execution conditions of subsequent candidate PSCells. In this case, the list of subsequent candidate PSCells may be included in the candidate PSCell configuration of each initially prepared candidate PSCell.

[0099] Figure 8 Another example data and logic flow 800 for selective SCG activation is shown. Selective SCG activation can be initiated by the source SN instead of the MN. Figure 8 Example data and logic flows may include the following information exchange between UE 802, MN 804, source SN 806, candidate SN 808, and 810:

[0100] Step 1: The source SN initiates the SCG selective activation process by sending an SN change request message to the MN. This message may include at least one of the following:

[0101] A list of candidate SN IDs suggested by the source SN;

[0102] Measurements related to candidate SNs;

[0103] A list of proposed PSCell candidates recommended by the source SN;

[0104] Execution conditions for each proposed PSCell candidate;

[0105] The upper limit on the number of PSCells that can be prepared from each candidate SN;

[0106] Reference SCG configuration generated from the source SN;

[0107] This indicates that the request is for selective activation;

[0108] Indicate whether the candidate SN / PSCell can suggest an indication for a subsequent candidate PSCell for the next / subsequent CPC;

[0109] For each candidate PSCell prepared by the candidate SN, there is an upper limit to the number of PSCells that can be prepared for the next / subsequent CPC.

[0110] Figure 8Steps 2-7 and Figure 7 Steps 1-6 are similar.

[0111] Step 8: The MN can send an SN change confirmation message to the source SN to indicate to the source SN that the SCG selective activation process has been configured / ready.

[0112] Figure 8 Steps 9-14c and Figure 7 The steps are similar to 8-13c.

[0113] In some example implementations, the SCG selective activation configuration may include at least one of the following:

[0114] One or more reference configurations. A reference configuration may contain an RRCReconfiguration message. Reference configurations may include an MCG reference configuration and / or an SCG reference configuration;

[0115] A list of candidate PSCell / SCG configurations, which may include at least one of the following:

[0116] Candidate PSCell IDs, such as candidate configuration indexes or PCI+ frequencies;

[0117] Candidate PSCell configurations;

[0118] The execution conditions of the associated candidate PSCell. Execution conditions can be used for CPCs initiated by CPA and MN;

[0119] A list of sk counters or SN keys used for candidate PSCells; or

[0120] Reference configuration ID to indicate the reference configuration used for the candidate PSCell;

[0121] A list of candidate PSCell information to be used when the indicated candidate PSCell is the currently serving PSCell. This information may include at least one of the following:

[0122] Service / Source PSCell ID: This ID can indicate a candidate PSCell ID in the list above, such as a candidate configuration index or PCI+ frequency. When the UE's current service PSCell ID matches this PSCell ID, the UE uses information from the associated / follow-up list (i.e., the list of candidate PSCells to be evaluated) for the next CPC evaluation and execution;

[0123] A list of candidate PSCells to be evaluated, which may include at least one of the following:

[0124] Candidate PSCell ID (e.g., candidate configuration index), PCI+ frequency (to indicate the candidate PSCell to be evaluated), and associated candidate PSCell configuration from the candidate PSCell / SCG configuration list;

[0125] The execution conditions of the associated candidate PSCell.

[0126] In some example implementations, the list of candidate PSCells to be evaluated can be included in the candidate PSCell configuration.

[0127] The following is an example of the signaling structure for SCG selective activation configuration:

[0128] CandidatePSCellConfigList — A list of candidate PSCell configurations

[0129] CandidateConfigId — Candidate PSCell Configuration ID

[0130] CandidatePSCellConfig (including RRCReconfiguration messages) — Candidate PSCell Configuration

[0131] >CondExecutionCondition — The execution condition of the associated candidate PSCell

[0132] Sk-counterList — A list of Sk counters for candidate PSCells

[0133] ReferenceConfigId

[0134] CandidatePSCellList — A list of candidate PSCell information

[0135] >Source / Service PSCell ID (ID can be PCI + frequency, or candidate PSCell configuration ID, such as CandidateConfigId) — When the PSCell ID of the current service matches this PSCell ID, the UE uses the information in the associated CandidateToEvaluationList to perform CPC evaluation and execution.

[0136] CandidateToEvaluationList — A list of candidate PSCells to be evaluated when the current service's PSCell becomes the PSCell indicated in the candidate PSCell ID.

[0137] >>CandidateConfigId — Indicates the candidate PSCell to be evaluated, and the associated candidate PSCell configuration from CandidatePSCellConfigList.

[0138] >>CondExecutionCondition — The execution condition of the associated candidate PSCell.

[0139] The second list of candidate PScell ​​information contains the second-level list of candidate PScells as described above. In some example embodiments, the list of candidate PSCell / SCG configurations and the list of candidate PSCell information can be combined into a single list. For example, the candidate PSCell ID can be indicated by the candidate PSCell configuration ID.

[0140] Process candidate PSCell / SCG configuration

[0141] When an SCG is released or deactivated / activated, the NW can explicitly instruct how to handle the stored candidate PSCell / SCG configurations, such as whether to retain such candidate PSCell / SCG configurations and / or which candidate PSCell / SCG configurations should be retained (e.g., if they are needed in subsequent PSCell changes / selections).

[0142] For example, if a candidate PSCell / SCG configuration is retained after the SCG is released, the retained candidate PSCell / SCG configuration can be reused for subsequent CPAs. In this case, for example, the retained candidate PSCell / SCG can be configured with an A4 event (as described above) as an execution condition. For example, such an execution condition can be provided by the following alternatives:

[0143] Alternative 1: Execution conditions are provided / updated via the RRCReconfiguration message that instructs the SCG to release.

[0144] Alternative 2: Execution conditions based on A4 events can be pre-configured with candidate PSCell / SCG configurations. For example, for each candidate PSCell / SCG, it can be associated with a set of at least two execution conditions:

[0145] A set based on A4 events generated by MN, used for CPA or CPC initiated by MN.

[0146] Another set is based on A3 / A5 events used for CPC (which can be generated by MN, source SN, or candidate SN).

[0147] In some example implementations, for PCell changes between MNs, the CPA / CPC configuration can be released by the NW through explicit instructions.

[0148] 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.

[0149] In some example implementations, if the indication is sent from the target MN, the source MN may need to notify the target MN via a HO request message that the CPA / CPC has been configured to the UE and / or the configured candidate PSCell / SCG list. The target MN can then include a release indication in the HO command (i.e., the RRCReconfiguration message) to release the CPA / CPC configuration or indicate which candidate PSCells should be released or retained. Alternatively, the target MN can also send a release indication via the RRCReconfiguration message after the UE has successfully completed random access to the target PCell.

[0150] Conditional switching (CHO) with multiple candidate SCGs

[0151] For a CHO with candidate SCGs, the network provides candidate PCell configurations with candidate PSCell configurations (e.g., CHO configurations including MCG and SCG configurations), as well as execution conditions for the candidate PCell and candidate PSCell. Upon receiving the candidate configuration, the UE simultaneously evaluates both the candidate PCell and candidate PSCell. When the execution conditions for both the candidate PCell and candidate PSCell are simultaneously met, the UE executes the CHO procedure with SCGs to access the target PCell and target PSCell.

[0152] In some example implementations, the CHO preparation process with candidate SCGs is initiated by the source MN. This process may include at least one of the following steps:

[0153] Step 1: The source MN sends a handover request message to the candidate MN. This message may include the requested candidate PCellID, an indication that the request is for a CHO with a candidate SCG, and / or an indication that the candidate MN is requesting the execution conditions for generating a candidate PSCell to be prepared.

[0154] Step 2: The candidate MN determines one or more candidate SNs for the requested candidate PCell and sends an SN Add Request message to each candidate SN to request the candidate SN to prepare the candidate PSCell. If the candidate SN and the source SN are the same node, the candidate MN can instruct the SN to generate / provide the execution conditions for the prepared candidate PSCell. These execution conditions are generated based on the source SCG measurement configuration.

[0155] Step 3: The candidate SN replies to the candidate MN with a SN Add Request Confirmation Message. This message may include the prepared candidate PSCell ID, the candidate PSCell / SCG configuration, the execution conditions and / or the updated source SCG measurement configuration (if the candidate SN and the source SN are the same node).

[0156] Step 4: The candidate MN generates candidate configurations for both PCell and PSCell (i.e., an MNRRC reconfiguration message with both MCG and SCG configurations). The candidate MN can generate the execution conditions for the prepared candidate PSCell (e.g., event A4 threshold). The candidate MN then sends a switch request confirmation message to the source MN. This message includes at least one of the following:

[0157] Candidate configurations for PCell and PSCell;

[0158] One or more associated candidate PSCell IDs for a candidate PCell;

[0159] Execution conditions generated from candidate MN;

[0160] If the candidate SN and the source SN are on the same node, then the execution conditions are generated by the candidate SN;

[0161] Updated source SCG measurement configuration (if the candidate SN and source SN are on the same node); or

[0162] Instructions / requests indicate the execution conditions for generating candidate PSCells prepared by the source SN or source MN.

[0163] Step 5: If the execution conditions for the candidate PSCell generated by the MN are received, the source MN can generate execution conditions / transfer execution conditions to the UE based on the information received from the candidate MN, according to the source MCG MeasConfig. For example, the source MN uses a threshold set by the candidate MN in the source MCG MeasConfig to configure CondEvent A4 associated with the candidate PSCell frequency. If an indication instructing / requesting the source MN to generate the execution conditions for the prepared candidate PSCell is received, or if the execution conditions for the prepared candidate PSCell are not received, the source MN generates the execution conditions for the candidate PSCell based on the source MCG MeasConfig. If an indication instructing / requesting 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., an SN modification request message) to the source SN to request the source SN to generate the execution conditions. The request message may include one or more prepared candidate PSCell IDs and / or an indication of execution condition generation. The source SN generates execution conditions based on the source SCG MeasConfig and responds to the source MN with an SN request confirmation (e.g., an SN modification request confirmation message), including the execution conditions generated for the prepared candidate PSCell and / or the updated source SCG measurement configuration.

[0164] Step 6: The source MN generates an RRCReconfiguration message including a CHO with candidate SCG configurations and sends the message to the UE. The CHO with candidate SCG configurations includes candidate configurations for candidate PSCells and PSCells, as well as associated execution conditions for candidate PSCells and PSCells.

[0165] Handling reference configuration and candidate configuration

[0166] The network can pre-configure multiple candidate cell configurations for mobility, such as L1 / L2 triggered mobility (LTM), CHO, CPAC, selective activation of cell groups, etc. The network can provide a reference configuration as a baseline for candidate cell configurations to reduce signaling overhead.

[0167] LTM is a process in which the gNB receives an L1 measurement report from the UE, and based on this report, the gNB changes the UE's serving cell via a cell handover command using L1 or L2 signaling (e.g., DCI or MAC CE). This signaling indicates the LTM candidate cell configuration that the gNB has previously prepared and provided to the UE via RRC signaling. The cell handover is then triggered by the gNB selecting the indicated LTM candidate cell configuration as the target configuration.

[0168] In some example implementations, the network may explicitly provide a separate reference configuration. Upon receiving the reference configuration, the UE stores it separately.

[0169] In some example implementations, the network does not provide a separate reference configuration; that is, a separate reference configuration does not exist. The network indicates a candidate cell configuration as the reference configuration. Upon receiving this indication, the UE stores the indicated candidate cell configuration separately as the reference configuration.

[0170] In some example implementations, the network does not provide a separate reference configuration; that is, there is no separate reference configuration. The network provides candidate cell configurations as candidate incremental configurations based on the current UE configuration (used when receiving this candidate configuration) or the candidate full configuration.

[0171] In some example implementations, the UE performs at least one of the following operations to process candidate cell configuration:

[0172] If no separate reference configuration exists, the candidate incremental configuration is applied to the current UE configuration (used when this candidate configuration is received) to form a complete candidate configuration.

[0173] If a separate reference configuration exists, the candidate incremental configuration is applied on top of the reference configuration to form a complete candidate configuration.

[0174] When a complete candidate configuration is formed depends on the UE's implementation method, for example, when a candidate cell configuration is received or after mobility execution is triggered (e.g., after receiving an LTM handover command in the case of LTM, or after the execution conditions of the candidate cell are met in the case of CHO / CPAC / SCG selective activation, etc.).

[0175] After a complete candidate configuration is formed, the UE stores the generated candidate cell configuration for subsequent mobility.

[0176] The complete candidate configuration is applied, and the current UE configuration is replaced by an RRC reconfiguration procedure that performs configuration replacement (during reconfiguration execution / cell handover). For LTM, the replacement procedure does not necessarily reset MAC, RLC, or PDCP.

[0177] When forming a complete candidate configuration:

[0178] For Need R IE, the UE should only include a parameter in the full candidate configuration if the parameter is already included in the candidate incremental configuration.

[0179] For Need N IE, if a parameter is included in ToAddModList in the reference configuration but not in ToReleaseList in the candidate incremental configuration, or if a parameter is included in ToAddModList in the candidate incremental configuration, then the UE should include it in ToAddModList in the full candidate configuration, i.e., ToReleaseList does not exist in the full candidate configuration.

[0180] For Need M IE, if the parameter is included in the reference configuration or candidate incremental configuration, the UE should include it in the full candidate configuration.

[0181] When the complete candidate configuration is applied and the current UE configuration is replaced, the UE can perform at least one of the following:

[0182] First, clear / release all current dedicated radio configurations except for certain specific fields (e.g., RLC bearer, radio bearer), but retain current MAC, RLC, and PDCP entities, such as stored state variables and data stored in transmit and receive buffers;

[0183] Apply the fields from the complete candidate configuration according to the operations defined in section 5.3.5.3;

[0184] Whether to reset MAC / RLC / PDCP is determined based on the RRC configuration (e.g., cell set) of the target candidate cell. For example, for LTM, resetting MAC / RLC / PDCP may not be necessary if the candidate cell and the source cell belong to the same cell set; or

[0185] After applying the fields from the full candidate configuration, release the RLC bearer / radio bearer if it is not included in the ToAddModList of the full candidate configuration.

[0186] In some example implementations, the UE performs a compliance check on the reference configuration upon receiving it. If the UE detects a failure in the compliance check of the reference configuration, it can report the failure to the network via a UL message (e.g., an RRCReconfigurationComplete message). The UE can also discard the reference configuration.

[0187] In some example implementations, when to perform compliance checks on candidate cell configurations depends on the UE's implementation, such as after a complete candidate configuration is formed, after a candidate cell configuration is received, or after mobility execution is triggered.

[0188] The above description and accompanying drawings provide specific example embodiments and implementations. However, the described subject matter can be embodied in a variety of different forms, and therefore, the covered or claimed subject matter is intended to be construed as not being limited to any of the example embodiments set forth herein. The scope of the claimed or covered subject matter is reasonable. Among other things, the subject matter can be embodied as a method, apparatus, component, system, or non-transitory computer-readable medium for storing computer code. Therefore, embodiments can take the form of, for example, hardware, software, firmware, storage medium, or any combination thereof. For example, the above-described method embodiments can be implemented by a component, apparatus, or system including a memory and a processor by executing computer code stored in the memory.

[0189] Throughout the specification and claims, terms may have subtle meanings implied or implied in the context that go beyond their explicitly stated meaning. Similarly, the phrase "in one embodiment / implementation" as used herein does not necessarily refer to the same embodiment, and the phrase "in another embodiment / implementation" as used herein does not necessarily refer to a different embodiment. For example, the claimed subject matter may include combinations of all or some of the exemplary embodiments.

[0190] Generally, terms can be understood, at least in part, from their usage in context. For example, terms such as “and,” “or,” or “and / or” as used herein can include a variety of meanings, which depend at least in part on the context in which they are used. Typically, “or” means A, B, and C when used in an associative list, such as A, B, or C, in an inclusive sense, and A, B, or C in an exclusive sense. Additionally, the term “one or more,” as used herein, depends at least in part on the context and can be used to describe any feature, structure, or characteristic in a singular sense, or to describe a combination of features, structures, or characteristics in a plural sense. Similarly, terms such as “a,” “an,” or “the” can be understood to indicate singular or plural usage, at least in part on the context. Furthermore, the term “based on” can be understood to not necessarily convey a set of exclusive factors and may allow for additional factors that are not necessarily explicitly described, at least in part on the context.

[0191] References to features, advantages, or similar language in this specification do not imply that all features and advantages achievable with this solution should be or are included in any single implementation thereof. Rather, references to features and advantages are understood to mean that a specific feature, advantage, or characteristic described in connection with an embodiment is included in at least one embodiment of this solution. Therefore, discussions of features and advantages, as well as similar language, throughout this specification may, but not necessarily, refer to the same embodiment.

[0192] Furthermore, in one or more embodiments, the features, advantages, and characteristics of this solution can be combined in any suitable manner. Based on the description herein, those skilled in the art will recognize that this solution can be implemented without one or more specific features or advantages of a particular embodiment. In other instances, additional features and advantages that may not be present in all embodiments of this solution can be identified in certain embodiments.

Claims

1. A method executed by a master node MN for selectively activating cell groups for wireless terminals in a wireless network, the method comprising: Send a request message to the candidate secondary node SN to request that the wireless terminal prepare for the cell group selective activation process; Receive an acknowledgment message in response to the request message from the candidate SN, the acknowledgment message including a first list of cell identifiers of a set of candidate cells; A reconfiguration message is generated based on the confirmation message, and the reconfiguration message includes cell group selective activation configuration; as well as The reconfiguration message is sent to the wireless terminal.

2. The method according to claim 1, wherein, The confirmation message includes a second list of candidate SNs or cells corresponding to one of the candidate cells in the set of candidate cells. The second list of candidate SNs or cells includes subsequent candidates for Conditional Cell Change CPC when one of the candidate cells in the set of candidate cells becomes the current serving cell of the wireless terminal.

3. The method according to claim 1, wherein, The request message includes at least one of the following: Instructions are given to the candidate SN, indicating that the candidate SN is permitted to be suggested as a subsequent candidate cell for the next / subsequent CPC of the wireless terminal; A list of proposed candidate SNs or cell identifiers for the next / subsequent CPC; The upper limit on the number of subsequent candidate cells that can be prepared for the next / subsequent CPC for each candidate cell; A list or range of SN keys for the next / subsequent CPC; or A counter value or a list of counter values ​​used for SN key derivation in the next / subsequent CPC.

4. The method according to claim 2, wherein: The request message includes an indication to the candidate SN, indicating that the candidate SN is permitted to be suggested as a subsequent candidate cell for the next / 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 group of candidate cells; If the MN suggestion is included in the request message, then a second list of candidate SNs or cells corresponding to one of the candidate cells in the set of candidate cells is identified according to the MN suggestion; as well as The execution conditions for determining each of the candidate SNs or cells in the second list are based on the candidate cell measurement configuration.

5. The method according to claim 1, wherein, Selective activation of cell groups is initiated by the MN.

6. The method according to claim 1, wherein, Selective activation of a cell group is initiated by the source SN communicating with the wireless terminal.

7. The method of claim 6, further comprising receiving an SN change request message from the source SN before sending the request message to the candidate SN.

8. The method according to claim 7, wherein, The SN change request message includes at least one of the following: The instruction given to the MN indicates that the candidate SN is allowed to be suggested as a subsequent candidate cell for the next / subsequent CPC of the wireless terminal; A list of proposed candidate SNs or cell identifiers for the next / subsequent CPC; or The candidate SN can be the upper limit of the number of subsequent candidate cells that can be prepared for the next / subsequent CPC for each candidate cell.

9. The method according to claim 1, wherein, The generated reconfiguration message includes: Receive a second confirmation message from at least another candidate SN; and The reconfiguration message is generated based on the confirmation message and the second confirmation message.

10. The method of claim 1, further comprising generating a report and sending the report to the candidate SN to notify the candidate SN of a subset of subsequent candidates for conditional cell change included in a reconfiguration message to the radio terminal.

11. The method of claim 1, further comprising receiving from the wireless terminal a reconfiguration completion message in response to the reconfiguration message, the reconfiguration completion message including information for identifying a target SN selected by the wireless terminal.

12. The method according to claim 11, further comprising sending an SN reconfiguration complete message to the target SN.

13. The method of claim 11, further comprising sending a report message to a source SN connected to the wireless terminal, the report message instructing the source SN to retain or release the context of the wireless terminal, or to discard / release / update the current SN key.

14. The method of claim 12, further comprising sending a report message to each of the other candidate SNs, the report message instructing each of the other candidate SNs to retain or release a list of candidate cells prepared for a cell group selective activation process, or to discard / release / update a candidate SN key.

15. The method according to claim 1, wherein, The selective activation configuration for cell groups includes at least one of the following: A list of prepared candidate communities; The execution conditions for each prepared candidate cell in the list of prepared candidate cells; A list of prepared subsequent candidate cells for each prepared candidate cell in the prepared candidate cell list. and The execution conditions for each prepared subsequent candidate cell in the list of prepared subsequent candidate cells.

16. A method performed by a candidate SN for selectively activating a cell group for a wireless terminal in a wireless network, the method comprising: Receive a request message from the master node MN of the wireless terminal to request preparation of the cell group selective activation process for the wireless terminal; Prepare a first list of cell identifiers for a set of candidate cells; as well as Send an acknowledgment message to the MN, the acknowledgment message including a first list of cell identifiers.

17. The method of claim 16, further comprising preparing a second list of candidate SNs or cells corresponding to one of the candidate cells in the set of candidate cells, the second list of candidate SNs or cells including subsequent candidates for conditional cell change CPC when one of the candidate cells in the set of candidate cells becomes the current serving cell of the wireless terminal, wherein, The confirmation message also includes a second list of candidate SNs or cells corresponding to one of the candidate cells in the set of candidate cells.

18. The method according to claim 16, wherein, The request message includes at least one of the following: Instructions are given to the candidate SN, indicating that the candidate SN is permitted to be suggested as a subsequent candidate cell for the next / subsequent CPC of the wireless terminal; A list of proposed candidate SNs or cell identifiers for the next / subsequent CPC; The upper limit on the number of subsequent candidate cells that can be prepared for the next / subsequent CPC for each candidate cell; A list or range of SN keys for the next / subsequent CPC; or A counter value or a list of counter values ​​used for SN key derivation in the next / subsequent CPC.

19. The method of claim 17, further comprising receiving a report from the MN, the report notifying the candidate SN of a subset of subsequent candidates for conditional cell changes included in a reconfiguration message sent from the MN to the radio terminal.

20. A wireless communication device, the wireless communication device comprising a processor and a memory, wherein, The processor is configured to read code from the memory and implement the method of any one of claims 1 to 19.

21. A computer program product comprising computer-readable program medium code stored thereon, the code causing the processor to perform the method of any one of claims 1 to 19 when executed by a processor.

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