Managing primary cell group configurations

Abstract

Examples of the present disclosure relate to managing primary cell group (MCG) configuration during PSCell (Primary Secondary Cell) changes. In an example of the present disclosure, a user equipment comprises means for receiving, from a master node, a ready configuration for at least a first candidate target PSCell and a second candidate target PSCell, where the same MCG configuration is shared between the at least the first candidate target PSCell and the second candidate target PSCell. The user equipment further comprises means for performing a PSCell change from the source PSCell to the first candidate target PSCell and reserving the preparation configuration after the PSCell change. The PSCell change is performed in the absence of a PCell change.

Description

Technical Field

[0001] Examples of the present disclosure relate to managing Master Cell Group (MCG) configurations. Some relate to optimized selective activation, and to managing Master Cell Group (MCG) configurations during PSCell (primary secondary cell) changes. Background Art

[0002] In New Radio - Dual Connectivity (NR-DC), a user equipment (UE) is connected to a primary node (MN) and a secondary node (SN) simultaneously. Both MN and SN can be associated with multiple cells or carriers. Multiple cells or carriers can be referred to as a primary cell group (MCG) and a secondary cell group (SCG). The respective groups have one primary cell carrying a physical uplink control channel (PUCCH) and can have one or more secondary cells. The primary cell of an MCG is a PCell and the primary cell of a secondary cell is a PSCell. The respective cell groups can change during a handover process. Summary of the invention

[0003] According to various but not necessarily all examples of the present disclosure, a user equipment is provided, comprising components for performing the following operations: receiving a preparation configuration for at least a first candidate target PSCell (primary secondary cell) and a second candidate target PSCell from a master node, wherein the same MCG (primary cell group) configuration is shared between at least the first candidate target PSCell and the second candidate target PSCell; performing a PSCell change from a source PSCell to a first candidate target PSCell; and retaining the preparation configuration after the PSCell change, wherein the PSCell change is performed without a PCell change.

[0004] The prepared configuration of each candidate target PSCell may include a complete SCG (Secondary Cell Group) configuration of the corresponding candidate target PSCell.

[0005] The preparation configuration may be associated with a reference SCG (Secondary Cell Group) configuration, and the preparation configuration includes an incremental SCG configuration for each candidate target PSCell, wherein the respective incremental SCG configuration indicates the difference between the reference SCG configuration and the SCG configuration of the corresponding candidate target PSCell.

[0006] The preparation configuration may be associated with a complete MCG configuration shared between at least the first candidate target PSCell and the second candidate target PSCell.

[0007] For the corresponding candidate target PSCell, the prepared configuration may include a complete MCG configuration, wherein the complete MCG configuration is the same for at least the first candidate target PSCell and the second candidate target PSCell.

[0008] The preparation configuration may be associated with a reference MCG configuration, and the preparation configuration includes an incremental MCG configuration for a corresponding candidate target PSCell, wherein the corresponding incremental MCG configuration indicates a difference between the reference MCG configuration and the MCG configuration of the corresponding candidate target PSCell, and wherein the MCG configuration shared between at least the first candidate target PSCell and the second candidate target PSCell is the reference MCG configuration.

[0009] The reference MCG configuration may include an MCG configuration applicable to the source PSCell.

[0010] The component of the user equipment may be further configured to receive an indication that a same MCG configuration is shared between at least the first candidate target PSCell and the second candidate target PSCell.

[0011] The indication may be received in a radio resource control message.

[0012] The indication may include a delta MCG configuration indicating no change between the MCG configuration for the first candidate target PSCell and the MCG configuration for the second candidate target PSCell.

[0013] The preparation configuration may be a CPC (Conditional PSCell Change) configuration.

[0014] The MCG configuration may be used to maintain the link to the master node.

[0015] The MCG configuration and the SCG configuration may include at least one of the following:

[0016] (i) radio link control parameters;

[0017] (ii) medium access control parameters;

[0018] (iii) Packet Data Convergence Protocol parameters.

[0019] The component of the user equipment may be used to: perform another PSCell change from the first candidate target PSCell to the second candidate target PSCell; and access the retained preparation configuration to enable the same MCG configuration to be used for the first candidate target PSCell and the second candidate target PSCell.

[0020] According to various but not necessarily all examples of the present disclosure, a method is provided, comprising: receiving a preparation configuration for at least a first candidate target PSCell (primary secondary cell) and a second candidate target PSCell from a master node, wherein the same MCG (primary cell group) configuration is shared between at least the first candidate target PSCell and the second candidate target PSCell; performing a PSCell change from a source PSCell to the first candidate target PSCell; and retaining the preparation configuration after the PSCell change, wherein the PSCell change is performed without a PCell change.

[0021] According to various but not necessarily all examples of the present disclosure, a computer program is provided, comprising program instructions, which, when executed by a user equipment, causes the user equipment to at least perform: receiving a preparation configuration for at least a first candidate target PSCell (primary secondary cell) and a second candidate target PSCell from a master node, wherein the same MCG (primary cell group) configuration is shared between at least the first candidate target PSCell and the second candidate target PSCell; performing a PSCell change from a source PSCell to a first candidate target PSCell; and retaining the preparation configuration after the PSCell change, wherein the PSCell change is performed without a PCell change.

[0022] According to various but not necessarily all examples of the present disclosure, a master node is provided, which includes components for the following operations: requesting configuration information from at least a first candidate target secondary node associated with a first candidate target PSCell and at least a second candidate target secondary node associated with a second candidate target PSCell; receiving the requested configuration information; and transmitting a prepared configuration for at least the first candidate target PSCell (primary secondary cell) and the second candidate target PSCell to a user equipment, wherein the same MCG (primary cell group) configuration is shared between at least the first candidate target PSCell and the second candidate target PSCell.

[0023] According to various but not necessarily all examples of the present disclosure, a method is provided, comprising: requesting configuration information from at least a first candidate target secondary node associated with a first candidate target PSCell and at least a second candidate target secondary node associated with a second candidate target PSCell; receiving the requested configuration information; and transmitting to a user equipment a prepared configuration for at least the first candidate target PSCell (primary secondary cell) and the second candidate target PSCell, wherein the same MCG (primary cell group) configuration is shared between at least the first candidate target PSCell and the second candidate target PSCell.

[0024] According to various but not necessarily all examples of the present disclosure, a computer program is provided, comprising program instructions, which, when executed by a master node, causes the master node to at least perform: requesting configuration information from at least a first candidate target secondary node associated with a first candidate target PSCell and at least a second candidate target secondary node associated with a second candidate target PSCell; receiving the requested configuration information; and transmitting to a user equipment a prepared configuration for at least the first candidate target PSCell (primary secondary cell) and the second candidate target PSCell, wherein the same MCG (primary cell group) configuration is shared between at least the first candidate target PSCell and the second candidate target PSCell.

[0025] Although the above examples and optional features of the present disclosure are described separately, it should be understood that their provision in all possible combinations and arrangements is included in the present disclosure. It should be understood that various examples of the present disclosure may include any or all features described with respect to other examples of the present disclosure, and vice versa. In addition, it should be appreciated that any one or more or all features in any combination may be implemented / included / executed by devices, methods and / or computer program instructions as needed and as appropriate. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Some examples will now be described with reference to the accompanying drawings, in which:

[0027] Figure 1 An example network is shown;

[0028] Figure 2 An example PSCell change is shown;

[0029] Figure 3A and Figure 3B An example method is shown;

[0030] Figure 4 An example configuration is shown;

[0031] Figure 5 An example signaling procedure is shown;

[0032] Figure 6 An example configuration is shown;

[0033] Figure 7 An example signaling procedure is shown;

[0034] Figure 8 An example configuration is shown;

[0035] Fig. 9 An example signaling procedure is shown; and

[0036] Fig.10 An example controller is shown.

[0037] The drawings are not necessarily drawn to scale. For purposes of clarity and brevity, certain features and views of the drawings may be schematically shown or enlarged to scale. For example, the dimensions of some elements in the drawings may be enlarged relative to other elements to aid in explanation. Corresponding reference numerals are used in the drawings to indicate corresponding features. For purposes of clarity, not all reference numerals may be shown in all drawings.

[0038] definition

[0039] CPA Conditional PSCell Addition

[0040] CPAC Conditional PSCell Addition and Change

[0041] CPC Conditional PSCell Changes

[0042] DRB Data Radio Bearer

[0043] MAC Media Access Control

[0044] MCG Master Cell Group

[0045] MN Master Node

[0046] MR measurement report

[0047] MR-DC Multi-RAT Dual Connectivity

[0048] NR-DC New Radio Dual Connectivity

[0049] PDCP Packet Data Convergence Protocol

[0050] PSCell primary and secondary cells

[0051] PUCCH Physical Uplink Control Channel

[0052] RAT Radio Access Technology

[0053] RLC Radio Link Control

[0054] SCG Secondary Cell Group

[0055] SCPAC and CPAC

[0056] SN Secondary Node

[0057] S-SN Source-SN

[0058] T-SN Target-SN DETAILED DESCRIPTION

[0059] Figure 1An example of a network 100, such as a 5G NR network, is shown. The network 100 includes several different types of nodes 110, 120, 130. The different types of nodes may include terminal nodes 110 and network nodes. The network nodes may include service nodes 120 and core network nodes 130 and / or any other suitable type of device.

[0060] Service node 120 may be configured to communicate with terminal node 110. Core network node 130 communicates with service node 120. In some examples, core network node 130 communicates with terminal node 110.

[0061] In some examples, core network nodes 130 may be in communication with each other. In some examples, one or more service nodes 120 may be in communication with each other.

[0062] The network 100 may be a cellular network comprising several cells 122. Each cell is served by a serving node 120. The interface between the terminal node 110 and the serving node 120 defining the cells 122 is a wireless interface 124 in this example.

[0063] The serving node 120 comprises one or more cellular radio transceivers. The terminal node 110 comprises one or more cellular radio transceivers.

[0064] In the example shown, the cellular network 100 is a 3rd Generation Partnership Project (3GPP) network, where the terminal node 110 is a user equipment (UE) and the serving node 120 may be an access node such as a base station (gNB).

[0065] The term 'user equipment' is used to designate mobile equipment that includes a smart card or the like for authentication / encryption, such as a Subscriber Identity Module (SIM). In some examples, the term 'user equipment' is used to designate mobile equipment that includes embedded circuitry (such as a software SIM) as part of the user equipment for authentication / encryption.

[0066] The service node 120 may be a base station. The service node 120 may be any suitable type of base station. A base station is an access node. The service node 120 may be a network entity responsible for radio transmission and reception in one or more cells to or from the UE 110. The service node 120 may be a network element in a radio access network (RAN), or any other suitable type of network.

[0067] In radio communications, node operations may be performed at least in part in a central / centralized unit (e.g., a server, host, or node) operably coupled to a distributed unit DU (e.g., a radio head / node). Node operations may also be distributed among several servers, nodes, or hosts. It should also be understood that the distribution of work between core network operations and base station operations may vary depending on the implementation. Therefore, the 5G network architecture may be based on the so-called CU-DU split. One gNB-CU (gNB is an example of a base station or service node) may control one or more gNB-DUs. The term 'gNB' may correspond in 5G to an eNB in ​​LTE. A gNB-CU (central node) may control several spatially separated gNB-DUs as a transmit / receive (Tx / Rx) node. In some embodiments, the gNB-DU (also referred to as DU) may include, for example, a radio link control (RLC), a medium access control (MAC) layer, and a physical (PHY) layer, while the gNB-CU (also referred to as CU) may include layers above the RLC layer, such as a packet data convergence protocol (PDCP) layer, a radio resource control (RRC), and an Internet Protocol (IP) layer. Other functional splits are also possible. The skilled person may be considered familiar with the OSI (Other System Information) model and the functions within each layer.

[0068] The core network node 130 may be part of a core network. The core network node 130 may be configured to manage functions related to the connection with the UE 110. For example, the core network node 130 may be configured to manage functions such as connectivity, mobility, authentication, authorization, and / or other suitable functions.

[0069] exist Figure 1 In the example of FIG. 1 , the core network node 130 is shown as a single entity. In some examples, the core network node 130 may be distributed across several entities. For example, the core network node 130 may be cloud-based or distributed in any other suitable manner.

[0070] The network 100 may be, for example, a 4G or 5G network. For example, it may be a New Radio (NR) network using gNBs as access nodes. New Radio is the 3GPP name for 5G technology. In this case, the service node 120 may include a gNodeB (gNB) 120 configured to provide user plane and control plane protocol termination to the UE 110 and / or perform any other suitable functions. The gNBs 120 are interconnected to each other by way of an X2 / Xn interface 126. The gNBs 120 are also connected to a core network node 130 via an N2 interface 128. In other examples other types of networks and interfaces may be used. Other types of networks may include next generation mobile and communication networks, such as 6G networks.

[0071] In a dual connectivity mode such as New Radio - Dual Connectivity (NR-DC), UE 110 is simultaneously connected to a Primary Node (MN) and a Secondary Node (SN). MN is a radio access node that provides a control plane connection to the core network. It can be a primary gNB or any other suitable type of node. SN is a radio access node that does not have a control plane connection to the core network and provides additional resources to UE 110. It can be a secondary gNB or any other suitable type of node.

[0072] Both MN and SN can be associated with multiple cells or carriers. Multiple cells or carriers can be referred to as a master cell group (MCG) and a secondary cell group (SCG). MCG is a group of service cells associated with MN. SCG is a group of service cells associated with SN. The corresponding group has a primary cell carrying a physical uplink control channel (PUCCH) and may have one or more secondary cells, the primary cell of MCG is PCell, and the primary cell of the secondary cell is PSCell. The corresponding cell group can be changed during the switching process. Other cells of MCG and SCG are called secondary nodes.

[0073] Figure 2 An example PSCell change and bearer change that may occur after a PSCell change is shown. A PSCell change may include a conditional PSCell change (CPC) procedure or a conditional PSCell addition and change (CPAC). The CPC procedure and the CPAC procedure are PSCell change procedures that are performed only when the PSCell execution conditions are met. The CPC and CPAC procedures may occur without a change in the PCell. The MN may decide the CPC / CPAC execution conditions.

[0074] Figure 2 The example in shows an inter-SN PSCell change followed by an intra-SN PSCell change.

[0075] From the attached Figure 2 Initially, the UE 110 first connects to the first master node 120M and the first secondary node 120S_1. The solid lines between the UE 110 and the respective serving nodes 120 indicate the bearers used.

[0076] As shown by arrow 200, a first PSCell change procedure is performed. The first PSCell change 200 may be performed because the UE 110 has moved or for any other suitable reason. After the first PSCell change 200, the UE 110 is connected to the second secondary node 120S_2. The second secondary node 120S_2 has replaced the first secondary node 120S_1. In this example, the first PSCell change 200 is an inter-SN change because the SN connected to the UE 110 changes.

[0077] In this case, a PSCell change occurs because the UE 110 is now connected to a different SN and corresponding SCG. In this example, the second SN 120S_2 has the first PSCell.

[0078] The first PSCell change 200 will result in a change of the bearer and MCG configuration. The MCG configuration is a configuration for maintaining the link to the MN 120M. The change of the bearer is indicated by arrow 202. The dashed line indicates the bearer that has been changed. In this case, the MCG bearer is added and the SCG bearer is released. The MCG configuration can, for example, define how the load is distributed between PSCell 1 and the MN. As an example, the bearer can be changed from PSCell 1 to the MN because the new PSCell 1 cannot handle as much load as SN_1 (120S_1).

[0079] Figure 2 Also shown is a second PSCell change that can occur after the first PSCell change. The second PSCell change is indicated by arrow 204. The second PSCell change 204 can be performed because the UE 110 has moved or for any other suitable reason. After the second PSCell change 204, the UE 110 remains connected to the second secondary node 120S_2. However, the PSCell of the SN has changed so that the second SN 120S_2 is now using the second PSCell. In this example, the second PSCell change 204 is an intra-SN change because the SN connected to the UE 110 does not change.

[0080] The second PSCell may result in a remapping of the bearers and MCG configurations used as indicated by arrow 206. However, in this case, remapping of the bearers and MCG configurations may not be necessary because there may not be any changes in these aspects. In this case, the remapping may result in unnecessary interruptions due to the reset of the medium access control (MAC), radio link control (RLC), and packet data convergence protocol (PDCP). This will also result in unnecessary processing and power consumption at UE 110.

[0081] Examples of the present disclosure aim to reduce these disruptions by avoiding unnecessary remapping of MCG configuration and bearers after the CPAC process.

[0082] Figure 3A and Figure 3B An example method is shown that may be used in examples of the present disclosure. Figure 3A The method may be implemented by UE 110. Figure 3B The method can be implemented by MN 120M.

[0083] exist Figure 3A In the example of , the method includes: at block 300, receiving a preparation configuration for at least a first candidate target PSCell and a second candidate target PSCell from the MN 120M.

[0084] The preparation configuration may include a configuration to be used for a PSCell change. The preparation configuration may include a CPC (Conditional PSCell Change) configuration or any other suitable type of configuration.

[0085] In an example of the present disclosure, the received preparation configuration may indicate (or there may be separate information indicating) that the same MCG (primary cell group) configuration is shared among two or more PSCells. For example, the received preparation configuration may indicate that the same MCG (primary cell group) configuration is shared between at least the first candidate target PSCell and the second candidate target PSCell. In some examples, the received preparation configuration may indicate that the same MCG (primary cell group) configuration is shared among one or more candidate target PSCells and the source PSCell.

[0086] The preparation configuration for the corresponding candidate target PSCell may include information related to the SCG configuration for the corresponding candidate target PSCell. In some examples, the information may be provided as a complete SCG configuration for the corresponding candidate target PSCell. In this case, the preparation configuration may include a complete SCG configuration for the corresponding candidate target PSCell.

[0087] In some examples, a complete SCG configuration may not be provided, but an incremental SCG configuration may be used. In this case, the preparation configuration may be associated with a reference SCG configuration, and the preparation configuration may include an incremental SCG configuration for the corresponding candidate target PSCell. The incremental SCG configuration indicates the difference between the reference SCG configuration and the SCG configuration of the corresponding candidate target PSCell. The reference SCG configuration may be provided to the UE 110 as part of the preparation configuration or as a separate configuration message.

[0088] The preparation configuration of the corresponding candidate target PSCell may also include information related to the MCG configuration of the corresponding candidate target PSCell. The MCG configuration may be used to maintain the link to the MN.

[0089] In some examples, information related to the MCG configuration may be provided as the entire MCG configuration for the corresponding candidate target PSCell. In this case, the prepared configuration may include a complete MCG configuration for the corresponding candidate target PSCell. The same MCG configuration may be used for multiple PSCells. For example, the same MCG configuration may be used for two or more candidate target PSCells. In some examples, the same MCG configuration may be used for a source PSCell and one or more candidate target PSCells.

[0090] In some examples, instead of providing a complete MCG and / or SCG configuration within a preparation configuration, UE 110 may be provided with a bitmap that associates the preparation configuration with the corresponding MCG and / or SCG configuration. In this case, for example, a complete MCG configuration or several complete MCG configurations may be provided separately to UE 110, and the preparation configuration (e.g., SCG configuration) may be associated with the corresponding (or with the same) MCG configuration via a bitmap. If only one MCG configuration is shared by all candidate target PSCells, the bitmap may not be needed (because all SCG configurations are associated with the same MCG configuration by default), or the bitmap may be an empty bitmap.

[0091] In some examples, the preparation configuration may include an incremental MCG configuration. In this case, the preparation configuration may be associated with a reference MCG configuration, and the preparation configuration may include an incremental MCG configuration for the corresponding candidate target PSCell. The incremental MCG configuration indicates the difference between the reference MCG configuration and the MCG configuration of the corresponding candidate target PSCell. The reference configuration may be an MCG configuration shared by multiple PSCells. In some examples, the reference MCG configuration may include an MCG configuration applicable to the source PSCell. In this case, the corresponding incremental MCG configuration of the PSCell sharing the reference configuration will indicate that there is no difference between the reference MCG configuration and the MCG configuration for the corresponding PSCell. The reference MCG configuration may be provided to the UE as part of the preparation configuration or as a separate configuration message.

[0092] In some examples, UE 110 may also receive an indication that the same MCG configuration is shared between two or more PSCells. The two or more PSCells may be a first candidate target PSCell and a second candidate target PSCell. The two or more PSCells may be a source PSCell and one or more candidate target PSCells.

[0093] In some examples, the indication that the same MCG configuration is shared between two or more PSCells may include an incremental MCG configuration indicating that there is no change between the MCG configuration for the first PSCell and the MCG configuration for the second PSCell. The first PSCell may be a first candidate target PSCell and the second PSCell may be a second candidate target PSCell. In some examples, the first PSCell may be a source PSCell and the second PSCell may be a candidate target PSCell.

[0094] The indication that the same MCG configuration is shared between two or more PSCells may be received in any suitable message. In some examples, the indication may be received in a radio resource control (RRC) message such as an RRC reconfiguration message or any other suitable message.

[0095] The MCG configuration and the SCG configuration may include any suitable information or parameters. In some examples, the corresponding parameters may include at least one of the following: a radio link control (RLC) parameter, a media access control (MAC) parameter, a packet data convergence protocol (PDCP) parameter, or any other suitable information or parameter.

[0096] At block 302 , the method includes performing a PSCell change from a source PSCell to a first candidate target PSCell.

[0097] At block 304, the method includes retaining a preparation configuration after a PSCell change, wherein the PSCell change is performed without a PCell change. Retention of the preparation configuration may include storing the preparation configurations so that they can be accessed and used for further PSCell changes. In some examples, the preparation configurations are stored including a shared MCG configuration.

[0098] In some examples, UE 110 may perform further PSCell changes. For example, UE 110 may perform a PSCell change from a first candidate PSCell to a second candidate PSCell. In such an example, UE 110 may access a retained preparation configuration so that the same MCG configuration can be used for the first candidate target PSCell and the second candidate target PSCell. Therefore, there is no need to remap the existing bearers of the MCG (MN / PCell).

[0099] The retention of the preparation configuration helps to avoid unnecessary interruptions due to the resetting of the configuration. This can also help to reduce the required signaling, since the MN does not need to resend the preparation configuration.

[0100] Figure 3BAn example method that may be performed by the MN 120M is shown. Figure 3A The UE 110 may be connected to perform the method Figure 3B Method of MN 120M.

[0101] exist Figure 3B In an example of , the method includes requesting configuration information from one or more candidate target SNs at block 310. The one or more candidate target SNs may include a first candidate target secondary node associated with at least a first candidate target PSCell and a second candidate target secondary node associated with at least a second candidate target PSCell.

[0102] The request may be made using any suitable message such as an SN Attach Request.

[0103] At block 312, the method includes receiving the requested configuration information. The requested information may be received using any suitable message such as an SN add request confirmation. In one embodiment, the received configuration information may include at least a portion of the prepared configuration described above, or in general information on which the prepared configuration is based.

[0104] At box 314, the method includes: transmitting a prepared configuration for at least a first candidate target PSCell and a second candidate target PSCell to UE 110. The same MCG configuration is shared between two or more PSCells. For example, the same MCG configuration can be shared between at least the first candidate target PSCell and the second candidate target PSCell. In some examples, the same MCG configuration can be shared between the source PSCell and one or more candidate target PSCells.

[0105] The preparation configuration may inform UE 110 that the same MCG configuration is shared between two or more PSCells.

[0106] Figure 4 Schematically illustrated are example preparation configurations 400 that may be used in examples of the present disclosure. These preparation configurations 400 may inform the UE 110 that the same MCG configuration is applicable to multiple PSCells.

[0107] exist Figure 4 In the example of FIG. 4 , three preparation configurations 400 are shown. In this example, the preparation configuration 400 is a CPC configuration. Other types of configurations may be used in other examples of the present disclosure.

[0108] Different preparation configurations 400 are used for different PSCells. Different PSCells may be associated with different SNs. Figure 4In the example of FIG. 4 , the first preparation configuration 400_1 is used for the first candidate target PSCell, the second preparation configuration 400_2 is used for the second candidate target PSCell, and the third preparation configuration 400_3 is used for the third candidate target PSCell. In other examples, other numbers of preparation configurations 400 and corresponding PSCells may be used.

[0109] The corresponding preparation configuration 400 may include information indicating the MCG configuration and information indicating the SCG configuration for the corresponding PSCell.

[0110] exist Figure 4 In the example of , a bitmap or another suitable means may be used to associate a corresponding preparation configuration 400 with a corresponding MCG configuration 404. In this illustrative example, the bitmap may refer to a first MCG configuration 404_1 and a second MCG configuration MCG 404_2. The preparation configuration 400 indicates which of these MCG configurations are applicable to the corresponding PSCell. In this example, the first preparation configuration 400_1 is associated with the first MCG configuration 404_1, and the second preparation configuration 400_2 is also associated with the first MCG configuration 404_1. This indicates that the first MCG configuration 404_1 is shared between multiple PSCells. In this example, the third preparation configuration 400_3 is associated with the second MCG configuration 404_2. This indicates that the MCG configuration may be different for at least some PSCells.

[0111] exist Figure 4 In the example of , the information indicating the SCG configuration may include an incremental SCG configuration 406. In this example, the preparation configuration 400 is associated with a reference SCG configuration 402. The reference SCG configuration 402 may include a reference parameter set for the SCG configuration. The reference SCG configuration 402 may include SCG parameters for the source PSCell.

[0112] The incremental SCG configuration 406 includes the difference between the reference SCG configuration 402 and the SCG configuration applicable to the corresponding PSCell. Figure 4 In the example of , the first incremental SCG configuration 406_1 is included in the first preparation configuration 400_1, the second incremental SCG configuration 406_2 is included in the second preparation configuration 400_2, and the third incremental SCG configuration 406_3 is included in the third preparation configuration 400_3.

[0113] The MCG configuration and the SCG configuration may include RLC parameters, MAC parameters, PDCP parameters and / or any other suitable information that may be used to remap or reset bearers when a PSCell change occurs.

[0114] Figure 5An example signaling procedure is shown that may be used in examples of the present disclosure. Figure 4 The example preparation configuration 400 shown may be used to Figure 5 In the example.

[0115] At block 500, UE 110 transmits a measurement report (MR) to MN 120M.

[0116] At block 502, the MN 120M prepares a reference SCG configuration 402. The reference SCG configuration 402 may be the configuration of the source PSCell or some other reference SCG configuration. The reference SCG configuration 402 provides a reference against which the incremental SCG configuration may be compared. The MN 120M may also initiate a CPAC procedure. This may be an inter-SN CPAC procedure involving an SN change. This may correspond to Figure 2 The first PSCell change is shown. The inter-SN CPAC process can be initiated based on the received MR.

[0117] At blocks 504 and 506, the MN 120M transmits a request for configuration information to the target SNs. The SN add request may be used to request configuration information. At block 504, the MN 120M sends the SN add request to the first target SN, and at block 506, the MN 120M sends the SN add request to the second target SN. Figure 5 In the example of FIG. 1 , only two target SNs are shown, but the MN 120M may send requests for configuration information to any number of target SNs.

[0118] The corresponding SN attachment request may include an indication of the MCG configuration. Figure 4 If the preparation configuration 400 shown in is used, the first MCG configuration 404-1 will be indicated for the first two SNs, and the second MCG configuration 404-2 will be indicated for the third SN.

[0119] The corresponding SN attachment request may also include an indication of a reference SCG configuration 402. The same reference SCG configuration 402 may be sent to each target SN. The reference SCG configuration 402 may be used by the corresponding target SN to determine the incremental SCG configuration. The reference SCG configuration 402 may be the configuration for the source PSCell. Alternatively, the reference SCG configuration may be generally known to the candidate target SN (providing the candidate target PSCell).

[0120] At blocks 508 and 510, the MN 120 receives a response to the request for configuration information. The received response may include the requested configuration information. The requested information may be received using any suitable message, such as an SN Attach Request Acknowledgement.

[0121] At block 508, the MN 120M receives a request confirmation from the first target SN, and at block 510, the MN 120M receives a request confirmation from the second target SN. The request confirmation may include an incremental SCG configuration 406 for the PSCell of the corresponding target SN. Figure 5 In the example of FIG. 1 , the MN 120M is shown as receiving configuration information from two target SNs, however, the MN 120M may receive configuration information of any number of target SNs.

[0122] At block 512, MN 120M sends an RRCReconfiguration message to UE 110. The RRCReconfiguration message may include MN RRC reconfiguration information and SN conditional RRC reconfiguration. As an example, the RRC reconfiguration message may include a reference SCG configuration, an incremental SCG configuration, and a related MCG configuration. These or a subset of these may be referred to as a preparation configuration.

[0123] The RRCReconfiguration message may include an indication that the same MCG configuration may be shared between multiple PSCells. This indication may be made using the prepare configuration 400 or any other suitable means. Figure 4 In the example preparation configuration 400, the same MCG configuration 404_1 is associated with both the first candidate target PSCell and the second candidate target PSCell. This indicates that the same MCG configuration 404_1 is shared between at least the first candidate PSCell and the second candidate target PSCell.

[0124] The SCG configuration may also be transmitted in the RRCReconfiguration message. The SCG configuration information may include a reference SCG configuration 402 and an incremental SCG configuration 406 for each candidate PSCell.

[0125] At block 514, UE 110 responds to the RRCReconfiguration message by sending an RRCReconfiguration Complete message to MN 120M.

[0126] If the execution condition for the first PSCell is satisfied, then at block 516, UE 110 sends an RRCReconfiguration Complete message to MN 120M. The RRCReconfiguration Complete message indicates that the PSCell will be changed from the source PSCell to the first candidate target PSCell.

[0127] At box 518, UE 110 applies the MCG configuration and SCG configuration indicated in the received preparation configuration 400 to the first candidate target PSCell. In this case, the first MCG configuration 404_1 will be applied to the first candidate target PSCell. The first SCG configuration will be applied by accessing the first incremental SCG file 406_1 and applying the differences indicated therein to the reference SCG configuration 402. It should be noted that MN 120M may not send the reference SCG configuration and the incremental SCG configuration to UE 110, but instead determine the complete SCG configuration based on the reference SCG configuration and the incremental SCG configuration for each PSCell, and provide the complete SCG configuration as the preparation configuration 400 to UE 110. In some examples, if UE 110 knows the reference configuration, MN 120M may not need to send the complete SCG configuration to UE 110 but only send the incremental SCG configuration to UE 110.

[0128] At block 520, the MN 120M sends an SN release request to the source SN, and at block 522, the source SN responds to the SN release request by sending an SN release request acknowledgment to the MN 120M.

[0129] At block 524, the MN 120M sends an SN reconfiguration complete message to the first target SN including the first candidate target PSCell.

[0130] At block 526, UE 110 performs a random access procedure to the first candidate target PSCell of the first target SN.

[0131] At block 528, the source SN sends a state transfer to the MN 120M to enable data forwarding, and at block 530, the MN 120M sends an SN state transfer to the first target SN for data forwarding. At block 532, the MN 120M sends a UeContextRelease to the source SN.

[0132] After the PSCell change, the UE 110 retains the received preparation configurations. The preparation configurations may be retained so that they may be accessed and used for subsequent PSCell changes.

[0133] At block 534, UE 110 continues to make measurements and check CPC status. If UE 110 detects that the execution condition for the second candidate target PSCell is met, UE 110 sends RRCReconfigurationComplete to MN 120M at block 536. This message indicates that the PSCell will be changed from the first candidate target PSCell to the second candidate target PSCell.

[0134] After transmitting the RRCReconfigurationComplete message, the UE 110 applies the MCG configuration and the SCG configuration for the second candidate target PSCell at block 534. The UE 110 may apply the MCG configuration and the SCG configuration for the second candidate target PSCell by accessing the already retained preparation configuration 400. The MN 120M does not need to send further preparation configurations 400.

[0135] In this case, the retained prepared configuration 400 indicates that the same MCG configuration 404_1 is shared for both the first candidate target PSCell and the second candidate target PSCell. Therefore, the UE 110 does not reset the MCG configuration for changing the PSCell to the second candidate target PSCell. This avoids resetting the MCG configuration unnecessarily.

[0136] The second SCG configuration will be applied by accessing the delta SCG configuration 406_2 of the second candidate target PSCell and applying the differences indicated therein to the reference SCG configuration 402 .

[0137] At block 540, the MN 120M sends an SN release request to the first target SN, and at block 542, the first target SN responds to the SN release request by sending an SN release request acknowledgment to the MN 120M.

[0138] At block 544, the MN 120M sends an SN reconfiguration complete message to the second target SN including the second candidate target PSCell.

[0139] At block 546, UE 110 performs a random access procedure to PSCell 2 of the second target SN.

[0140] At block 548, the first target SN sends a state transfer to the MN 120M to enable data forwarding, and at block 550, the MN 120M sends the SN state transfer to the second target SN for data forwarding. At block 552, the MN 120M sends a UeContextRelease to the first target SN.

[0141] Figure 6 Another set of example preparation configurations 400 that may be used in examples of the present disclosure is schematically shown. These preparation configurations 400 may also inform the UE 110 that the same MCG configuration is applicable to multiple PSCells.

[0142] exist Figure 6 In the example of FIG. 4 , three preparation configurations 400 are shown. In this example, the preparation configuration 400 is a CPC configuration. Other types of configurations may be used in other examples of the present disclosure.

[0143] Different preparation configurations 400 are used for different PSCells. Different PSCells may be associated with different SNs. Figure 6 In the example, the first preparation configuration 400_1 is used for the first candidate target PSCell, the second preparation configuration 400_2 is used for the second candidate target PSCell, and the third preparation configuration 400_3 is used for the third candidate target PSCell. Other numbers of preparation configurations 400 and corresponding PSCells may be used in other examples.

[0144] The corresponding preparation configuration 400 may include information indicating the MCG configuration and information indicating the SCG configuration of the corresponding PSCell.

[0145] exist Figure 6 In the example of FIG. 4 , the preparation configuration 400 includes a complete MCG configuration 600 for the corresponding PSCell.

[0146] In this example, the first preparation configuration 400_1 includes the first MCG configuration 600_1, and the second preparation configuration 400_2 also includes the first MCG configuration 600_1. This indicates that the first MCG configuration 600_1 is the same in multiple PSCells. In this example, the third preparation configuration 400_3 includes the second MCG configuration 600_2. This indicates that the MCG configuration may be different for at least some PSCells.

[0147] exist Figure 6 In the example of FIG. 4 , the information indicating the SCG configuration may include an incremental SCG configuration 406, and the preparation configuration 400 is associated with the reference SCG configuration 402. The incremental SCG configuration and the reference SCG configuration 402 may be as described in detail in relation to FIG. Figure 4 as described.

[0148] The MCG configuration and the SCG configuration may include RLC parameters, MAC parameters, PDCP parameters and / or any other suitable information that may be used to remap or reset bearers when a PSCell change occurs.

[0149] Figure 7 An example signaling procedure is shown that may be used in examples of the present disclosure. Figure 6 The example preparation configuration 400 shown may be used to Figure 7 In the example.

[0150] At block 700, UE 110 sends a measurement report (MR) to MN 120M.

[0151] At block 702, the MN 120M prepares a reference SCG configuration 402. The reference SCG configuration 402 may be the configuration of the source PSCell or any predefined reference configuration. The reference SCG configuration 402 provides a reference that may be compared with the incremental SCG configuration. The MN 120M may also initiate a CPAC procedure. This may be an inter-SN CPAC procedure involving changes in the SNs. This may correspond to Figure 2 The first PSCell change is shown. The inter-SN CPAC process may be initiated based on the received MR.

[0152] At blocks 704 and 706, the MN 120M sends a request for configuration information to the target SN. The SN add request may be used to request configuration information. At block 704, the MN 120M sends an SN add request to the first target SN, and at block 706, the MN 120M sends an SN add request to the second target SN. Figure 7 In the example of FIG. 1 , only two target SNs are shown, but the MN 120M may send requests for configuration information to any number of target SNs.

[0153] The corresponding SN attachment request may include an indication of the MCG configuration. Figure 6 If the preparation configuration 400 shown in is used, the first MCG configuration 600_1 will be indicated for the first two SNs, and the second MCG configuration 600_2 will be indicated for the third SN.

[0154] The corresponding SN attach request may include an indication of the reference SCG configuration 402 unless it already knows the corresponding PSCell. The same reference SCG configuration 402 may be sent to each target SN. The reference SCG configuration 402 may be used by the corresponding target SN to determine the incremental SCG configuration. The reference SCG configuration 402 may be the configuration for the source PSCell.

[0155] At blocks 708 and 710, the MN 120M receives a response to the request for configuration information. The received response may include the requested configuration information, such as an incremental SCG configuration. The requested information may be received using any suitable message, such as an SN Add Request Acknowledgement.

[0156] At block 708, the MN 120M receives a request confirmation from the first target SN, and at block 710, the MN 120M receives a request confirmation from the second target SN. The request confirmation may include an incremental SCG configuration 406 for the PSCell of the corresponding target SN. Figure 7 In the example of FIG. 1 , the MN 120M is shown as receiving configuration information from two target SNs, however, the MN 120M may receive configuration information of any number of target SNs.

[0157] At block 712, MN 120M sends an RRCReconfiguration message to UE 110. The RRCReconfiguration message includes MN RRC reconfiguration information and SN conditional RRC reconfiguration. As an example, the RRC reconfiguration message may include a reference SCG configuration, an incremental SCG configuration, and a related MCG configuration. These or a subset of these may be referred to as a preparation configuration.

[0158] The RRCReconfiguration message may include an indication that the same MCG configuration may be shared between multiple PSCells. This indication may be made using the Prepare Configuration 400 or any other suitable means. Figure 6 If the example preparation configuration 400 is used, the same first MCG configuration 600_1 is associated with both the first candidate target PSCell and the second candidate target PSCell. This indicates that the same MCG configuration 600_1 exists in at least the first candidate PSCell and the second candidate target PSCell.

[0159] The SCG configuration may also be transmitted in the RRCReconfiguration message. The SCG configuration information may include a reference SCG configuration 402 and an incremental SCG configuration 406 for each candidate PSCell. It should be noted that instead of sending the reference SCG configuration and the incremental SCG configuration to the UE 110, the MN 120M may determine the complete SCG configuration based on the reference SCG configuration and the incremental SCG configuration for each PSCell, and provide the complete SCG configuration as a prepared configuration to the UE 110. As another embodiment, if the UE 110 knows the reference configuration, the MN 120M may not need to send the reference configuration to the UE 110 but only send the incremental SCG configuration to the UE 110.

[0160] At block 714, UE 110 responds to the RRCReconfiguration message by sending an RRCReconfiguration Complete message to MN 120M.

[0161] If the execution condition for the first candidate target PSCell is satisfied, then at block 716, UE 110 sends an RRCReconfiguration Complete message to MN 120M. The RRCReconfiguration Complete message indicates that the PSCell will be changed from the source PSCell to the first candidate target PSCell.

[0162] At block 718, the UE 110 applies the MCG configuration and the SCG configuration for the first candidate target PSCell as indicated in the received preparation configuration 400. In this case, the first MCG configuration 600_1 will be applied to the first candidate target PSCell. The first SCG configuration will be applied, for example, by accessing the first incremental SCG file 406_1 and applying the differences indicated therein to the reference SCG configuration 402.

[0163] At block 720, the MN 120M sends an SN release request to the source SN, and at block 722, the source SN responds to the SN release request by sending an SN release request confirmation to the MN 120M.

[0164] At block 724, the MN 120M sends an SN reconfiguration complete message to the first target SN including the first candidate target PSCell.

[0165] At block 726, UE 110 performs a random access procedure to the first candidate target PSCell of the first target SN.

[0166] At block 728, the source SN sends a state transfer to the MN 120M to enable data forwarding, and at block 730, the MN 120M sends an SN state transfer to the first target SN for data forwarding. At block 732, the MN 120M sends a UeContextRelease to the source SN.

[0167] After the PSCell change, the UE 110 retains the received preparation configurations. The preparation configurations may be retained so that they may be accessed and used for subsequent PSCell changes.

[0168] At block 734, UE 110 continues to make measurements and check CPC status. If UE 110 detects that the execution condition for the second candidate target PSCell is met, UE 110 sends RRCReconfigurationComplete to MN 120M at block 736. This message indicates that the PSCell will be changed from the first candidate target PSCell to the second candidate target PSCell.

[0169] After transmitting the RRCReconfigurationComplete message, the UE 110 applies the MCG configuration and the SCG configuration for the second candidate target PSCell at block 734. The UE 110 may apply the MCG configuration and the SCG configuration for the second candidate target PSCell by accessing the already retained preparation configuration 400. The MN 120M does not need to send further preparation configurations 400.

[0170] In this case, the retained preparation configuration 400 indicates that the same MCG configuration 600_1 is the same for both the first candidate target PSCell and the second candidate target PSCell. Therefore, the UE 110 does not reset the MCG configuration for changing the PSCell to the second candidate target PSCell. This avoids resetting the MCG configuration unnecessarily.

[0171] The second SCG configuration will be applied by the incremental SCG configuration 406_2 for the second candidate target PSCell, and the differences indicated therein will be applied to the reference SCG configuration 402.

[0172] At block 740, the MN 120M sends an SN release request to the first target SN, and at block 742, the first target SN responds to the SN release request by sending an SN release request acknowledgement to the MN 120M.

[0173] At block 744, the MN 120M sends an SN reconfiguration complete message to the second target SN including the second candidate target PSCell.

[0174] At block 746, UE 110 performs a random access procedure to PSCell 2 of the second target SN.

[0175] At block 748, the first target SN sends a state transfer to the MN 120M to enable data forwarding, and at block 750, the MN 120M sends the SN state transfer to the second target SN for data forwarding. At block 752, the MN 120M sends a UeContextRelease to the first target SN.

[0176] Figure 8 Another set of example preparation configurations 400 that can be used in examples of the present disclosure is schematically shown. These preparation configurations 400 can also inform the UE 110 that the same MCG configuration is applicable to multiple PSCells. In this case, the preparation configuration 400 can also indicate that one or more of the MCG configurations are the same as the configuration used for the source PSCell.

[0177] exist Figure 8 In the example of FIG. 4 , three preparation configurations 400 are shown. In this example, the preparation configuration 400 is a CPC configuration. Other types of configurations may be used in other examples of the present disclosure.

[0178] Different preparation configurations 400 are used for different PSCells. Different PSCells may be associated with different SNs. Figure 8In the example of FIG. 4 , the first preparation configuration 400_1 is used for the first candidate target PSCell, the second preparation configuration 400_2 is used for the second candidate target PSCell, and the third preparation configuration 400_3 is used for the third candidate target PSCell. Other numbers of preparation configurations 400 and corresponding PSCells may be used in other examples.

[0179] The corresponding preparation configuration 400 may include information indicating the MCG configuration and information indicating the SCG configuration for the corresponding PSCell.

[0180] exist Figure 8 In the example of , the information indicating the MCG configuration may include an incremental MCG configuration 800. In this example, the preparation configuration 400 is associated with a reference configuration 802. The reference configuration 802 includes a reference MCG configuration 806. The reference MCG configuration 806 may include a reference parameter set for the MCG configuration. The reference MCG configuration 806 may include MCG parameters for the source PSCell.

[0181] The incremental MCG configuration 800 includes the differences between the reference MCG configuration 806 and the MCG configuration applicable to the corresponding PSCell. Figure 8 In the example, the first incremental MCG configuration 800_1 is used for the first preparation configuration 400_1, the second incremental MCG configuration 800_2 is used for the second preparation configuration 400_2, and the third incremental MCG configuration 800_3 is used for the third preparation configuration 400_3.

[0182] The corresponding incremental MCG configurations 800 may be different from each other, or one or more of them may be the same. If one or more incremental MCG configurations are the same, this indicates that the same MCG configuration is shared by multiple PSCells.

[0183] In some examples, one or more of the incremental MCG configurations 800 may indicate that there is no difference between the MCG configuration of the corresponding candidate target PSCell and the reference MCG configuration 806. This may indicate that the same MCG configuration may be applied to the source PSCell and one or more candidate target PSCells.

[0184] The preparation configuration 400 also includes information indicating the SCG configuration. The information indicating the SCG configuration may include the incremental SCG configuration 406. In this example, the reference configuration 802 also includes a reference SCG configuration 804. The reference SCG configuration 804 may include a reference parameter set for the SCG configuration. The reference SCG configuration 804 may include SCG parameters for the source PSCell.

[0185] The incremental SCG configuration 406 includes the difference between the reference SCG configuration 804 and the SCG configuration applicable to the corresponding PSCell. Figure 8 In the example of , the first incremental SCG configuration 406_1 is used for the first preparation configuration 400_1, the second incremental SCG configuration 406_2 is used for the second preparation configuration 400_2, and the third incremental SCG configuration 406_3 is used for the third preparation configuration 400_3.

[0186] The MCG configuration and the SCG configuration may include RLC parameters, MAC parameters, PDCP parameters and / or any other suitable information that may be used to remap or reset bearers when a PSCell change occurs.

[0187] Fig. 9 An example signaling procedure is shown that may be used in examples of the present disclosure. Figure 8 The example preparation configuration 400 shown may be used to Fig. 9 In the example.

[0188] At block 900, UE 110 transmits a measurement report (MR) to MN 120M.

[0189] At block 902, the MN 120M prepares a reference configuration 802. The reference configuration 802 may include a reference MCG configuration 806 and a reference SCG configuration 804. This provides a reference that may be compared to the incremental configuration. The MN 120M may also initiate a CPAC procedure. This may be an inter-SN CPAC procedure involving changes in the SNs. This may correspond to Figure 2 The first PSCell change is shown. The inter-SN CPAC process can be initiated based on the received MR.

[0190] At blocks 904 and 906, MN 120M sends a request for configuration information to the target SNs. The SN add request may be used to request configuration information, such as incremental information corresponding to the reference configuration described above. At block 904, MN 120M sends an SN add request to a first target SN, and at block 906, MN 120M sends an SN add request to a second target SN. Fig. 9 In the example of FIG. 1 , only two target SNs are shown, but the MN 120M may send requests for configuration information to any number of target SNs.

[0191] The corresponding SN attach request may also include an indication of a reference SCG configuration 804 and an indication of a reference MCG configuration 806 if the associated PSCell is not aware of these indications. The reference configurations may be used by the corresponding target SN to determine the incremental SCG configuration 406 and the incremental MCG configuration 800.

[0192] At blocks 908 and 910, the MN 120M receives a response to the request for configuration information. The received response may include the requested configuration information, such as delta information corresponding to the reference configuration described above. The requested information may be received using any suitable message, such as an SN Add Request Acknowledgement.

[0193] At block 908, the MN 120M receives a request confirmation from the first target SN, and at block 910, the MN 120M receives a request confirmation from the second target SN. The request confirmation may include an incremental SCG configuration 406 and an incremental MCG configuration 800 for the PSCell of the corresponding target SN. Fig. 9 In the example of FIG. 1 , the MN 120M is shown as receiving configuration information from two target SNs, however, the MN 120M may receive configuration information of any number of target SNs.

[0194] At block 912, MN 120M sends an RRCReconfiguration message to UE 110. The RRCReconfiguration message includes MN RRC reconfiguration information and SN conditional RRC reconfiguration.

[0195] The RRCReconfiguration message may include an indication that the same MCG configuration may be applied to multiple PSCells. This indication may be accomplished using the prepare configuration 400 or any other suitable means. Figure 8 If the example preparation configuration 400 is used, then an incremental MCG configuration indicating no difference means that the MCG configuration of the PSCell is the same as the reference MCG configuration 806. In some examples, the same incremental MCG configuration can be used for the preparation configuration 400 for multiple different PSCells. This can indicate that the same MCG configuration is shared by multiple different PSCells.

[0196] The SCG configuration may also be transmitted in the RRCReconfiguration message. The SCG configuration information may include a reference SCG configuration 806 and an incremental SCG configuration 406 for each candidate PSCell. As an example, the RRC reconfiguration message may include a reference SCG configuration, an incremental SCG configuration, a reference MCG configuration, and an incremental MCG configuration. These or a subset of these may be referred to as a preparation configuration. It should be noted that instead of sending a reference configuration and an incremental configuration to the UE 110, the MN 120M may determine a complete configuration based on the reference configuration and the incremental configuration for each PSCell, and provide the complete configuration as a preparation configuration to the UE 110. As another embodiment, if the UE 110 knows the reference configuration, the MN 120M may not need to send the reference configuration to the UE 110 but only send the incremental configuration to the UE 110.

[0197] At block 914, UE 110 responds to the RRCReconfiguration message by sending an RRCReconfiguration Complete message to MN 120M.

[0198] If the execution condition for the first candidate target PSCell is satisfied, then at block 916, UE 110 sends an RRCReconfiguration Complete message to MN 120M. The RRCReconfiguration Complete message indicates that the PSCell will be changed from the source PSCell to the first candidate target PSCell.

[0199] At box 918, the UE 110 applies the MCG configuration and the SCG configuration for the first candidate target PSCell as indicated in the received preparation configuration 400. In this case, the first MCG configuration will be applied to the first candidate target PSCell. The first MCG configuration can be applied, for example, by accessing the first incremental MCG configuration 800_1 and applying any changes indicated therein to the reference MCG configuration 806. The first SCG configuration can be applied, for example, by accessing the first incremental SCG configuration 406_1 and applying the changes indicated therein to the reference SCG configuration 804. If the first incremental MCG configuration 800_1 indicates that there are no differences to the reference MCG configuration 806, the MCG configuration of the source PSCell can be applied and no remapping or resetting of bearers is required.

[0200] At block 920, the MN 120M sends an SN release request to the source SN, and at block 922, the source SN responds to the SN release request by sending and SN release request confirmation to the MN 120M.

[0201] At block 924, the MN 120M sends an SN reconfiguration complete message to the first target SN including the first candidate target PSCell.

[0202] At block 926, UE 110 performs a random access procedure to PSCell 1 of the first target SN.

[0203] At block 928, the source SN sends a state transfer to the MN 120M to enable data forwarding, and at block 930, the MN 120M sends an SN state transfer to the first target SN for data forwarding. At block 932, the MN 120M sends a UeContextRelease to the source SN.

[0204] After the PSCell change, the UE 110 retains the received preparation configurations. The preparation configurations may be retained so that they may be accessed and used for subsequent PSCell changes.

[0205] At block 934, UE 110 continues to make measurements and check CPC status. If UE 110 detects that the execution condition for the second candidate target PSCell is met, UE 110 sends RRCReconfigurationComplete to MN 120M at block 936. This message indicates that the PSCell will be changed from the first candidate target PSCell to the second candidate target PSCell.

[0206] After transmitting the RRCReconfigurationComplete message, the UE 110 applies the MCG configuration and the SCG configuration for the second candidate target PSCell at block 934. The UE 110 may apply the MCG configuration and the SCG configuration for the second candidate target PSCell by accessing the already retained preparation configuration 400. The MN 120M does not need to send further preparation configurations 400.

[0207] The MCG configuration for the second candidate target PSCell may be applied, for example, by accessing the second incremental MCG configuration 800_2 and applying any differences indicated therein to the reference MCG configuration 806. Similarly, the SCG configuration for the second candidate target PSCell may be applied, for example, by accessing the second incremental SCG configuration 406_2 and applying any differences indicated therein to the reference SCG configuration 804. If the second incremental MCG configuration 800_2 indicates that there are no changes, the reference MCG configuration may be applied and no bearer remapping or reset is required.

[0208] At block 940, the MN 120M sends an SN release request to the first target SN, and at block 942, the first target SN responds to the SN release request by sending an SN release request acknowledgment to the MN 120M.

[0209] At block 944, the MN 120M sends an SN reconfiguration complete message to the second target SN including the second candidate target PSCell.

[0210] At block 946, UE 110 performs a random access procedure to PSCell 2 of the second target SN.

[0211] At block 948, the first target SN sends a state transfer to the MN 120M to enable data forwarding, and at block 950, the MN 120M sends the SN state transfer to the second target SN for data forwarding. At block 952, the MN 120M sends a UeContextRelease to the first target SN.

[0212] Fig.10 An example controller 1000 is shown. The controller 1000 may be provided within an entity such as the UE 110 or the MN 120M or any other suitable device, or the controller may be, for example, the UE 110 or the MN 120M. The controller 1000 may be implemented as a controller circuit. The controller 1000 may be implemented solely in hardware, have certain aspects in software, include firmware alone, or may be a combination of hardware and software (including firmware).

[0213] like Fig.10 As shown, the controller 1000 may be implemented using instructions that enable hardware functionality, for example, by using executable instructions of a computer program 1006 in a general or special purpose processor 1002, which may be stored on a computer-readable storage medium (disk, memory, etc.) executed by such a processor 1002.

[0214] The processor 1002 is configured to read from and write to the memory 1004. The processor 1002 may also include an output interface through which data and / or commands are output by the processor 1002, and an input interface through which data and / or commands are input into the processor 1002.

[0215] The memory 1004 stores a computer program 1006 including computer program instructions (computer program code) that controls the operation of the device when loaded into the processor 1002. The computer program instructions of the computer program 1006 provide logic and routines that enable the device to perform the method shown in the figure. The processor 1002 can load and execute the computer program 1006 by reading the memory 1004.

[0216] The controller 1000 thus includes: at least one processor 1002; and at least one memory 1004 storing instructions that, when executed by the at least one processor 1002, cause the UE 110 to at least perform:

[0217] receiving 300 a prepared configuration for at least a first candidate target PSCell (primary secondary cell) and a second candidate target PSCell from the master node 120M, wherein the same MCG (master cell group) configuration is shared between at least the first candidate target PSCell and the second candidate target PSCell;

[0218] performing 302 a PSCell change from a source PSCell to a first candidate target PSCell; and

[0219] A preparation configuration is retained 304 after a PSCell change, wherein the PSCell change is performed without a PCell change.

[0220] The controller 1000 thus comprises: at least one processor 1002; and at least one memory 1004 storing instructions which, when executed by the at least one processor 1002, cause the MN to at least perform:

[0221] requesting 310 configuration information from at least a first candidate target secondary node associated with a first candidate target PSCell and at least a second candidate target secondary node associated with a second candidate target PSCell;

[0222] receiving 312 the requested configuration information; and

[0223] Prepared configurations for at least a first candidate target PSCell (primary secondary cell) and a second candidate target PSCell are transmitted 314 to the UE 110, wherein the same MCG (primary cell group) configuration is shared between at least the first candidate target PSCell and the second candidate target PSCell.

[0224] The computer program 1006 may arrive at the apparatus via any suitable delivery mechanism 1008. The delivery mechanism 1008 may be, for example, a machine-readable medium, a computer-readable medium, a non-transitory computer-readable storage medium, a computer program product, a memory device, an article of manufacture such as a compact disc read-only memory (CD-ROM) or a digital versatile disk (DVD), or a solid-state memory that includes or tangibly embodies the computer program 1006. The delivery mechanism may be a signal configured to reliably transfer the computer program 1006. The apparatus may propagate or transmit the computer program 1006 as a computer data signal.

[0225] The computer program 1006 may include computer program instructions for causing the UE 110 to perform at least the following or at least the following operations:

[0226] receiving 300 a prepared configuration for at least a first candidate target PSCell (primary secondary cell) and a second candidate target PSCell from the master node 120M, wherein the same MCG (master cell group) configuration is shared between at least the first candidate target PSCell and the second candidate target PSCell;

[0227] performing 302 a PSCell change from a source PSCell to a first candidate target PSCell; and

[0228] A preparation configuration is retained 304 after a PSCell change, wherein the PSCell change is performed without a PCell change.

[0229] The computer program 1006 may include computer program instructions for causing the MN to at least perform the following operations or be designed to perform at least the following operations:

[0230] requesting 310 configuration information from at least a first candidate target secondary node associated with a first candidate target PSCell and at least a second candidate target secondary node associated with a second candidate target PSCell;

[0231] receiving 312 the requested configuration information; and

[0232] Prepared configurations for at least a first candidate target PSCell (primary secondary cell) and a second candidate target PSCell are transmitted 314 to the UE 110, wherein the same MCG (primary cell group) configuration is shared between at least the first candidate target PSCell and the second candidate target PSCell.

[0233] The present disclosure provides the following example implementations:

[0234] Example 1. A user equipment, comprising components for: receiving a preparation configuration for at least a first candidate target PSCell (primary secondary cell) and a second candidate target PSCell from a master node, wherein the same MCG (master cell group) configuration is shared at least between the first candidate target PSCell and the second candidate target PSCell; performing a PSCell change from a source PSCell to the first candidate target PSCell; and retaining the preparation configuration after the PSCell change, wherein the PSCell change is performed without a PCell change.

[0235] Example 2. The user equipment according to Example 1, wherein the prepared configuration for each candidate target PSCell comprises a complete SCG (Secondary Cell Group) configuration of the corresponding candidate target PSCell.

[0236] Example 3. A user equipment according to Example 1, wherein the preparation configuration is associated with a reference SCG (secondary cell group) configuration, and the preparation configuration includes an incremental SCG configuration for each candidate target PSCell, wherein the corresponding incremental SCG configuration indicates the difference between the reference SCG configuration and the SCG configuration of the corresponding candidate target PSCell.

[0237] Example 4. The user equipment of any one of Examples 1 to 3, wherein the preparation configuration is associated with a complete MCG configuration shared between at least the first candidate target PSCell and the second candidate target PSCell.

[0238] Example 5. The user equipment of any one of Examples 1 to 3, wherein the preparation configuration comprises a complete MCG configuration for a corresponding candidate target PSCell, wherein the complete MCG configuration is the same at least for the first candidate target PSCell and the second candidate target PSCell.

[0239] Example 6. A user equipment according to any one of Examples 1 to 3, wherein the preparation configuration is associated with a reference MCG configuration, and the preparation configuration includes an incremental MCG configuration for a corresponding candidate target PSCell, wherein the corresponding incremental MCG configuration indicates a difference between the reference MCG configuration and the MCG configuration of the corresponding candidate target PSCell, and wherein the MCG configuration shared between at least a first candidate target PSCell and the second candidate target PSCell is the reference MCG configuration.

[0240] Example 7. A user equipment according to any of the preceding examples, wherein the reference MCG configuration comprises the MCG configuration applicable to the source PSCell.

[0241] Example 8. The user equipment according to any preceding example, further comprising: receiving an indication that the same MCG configuration is shared between at least the first candidate target PSCell and the second candidate target PSCell.

[0242] Example 9. The user equipment of Example 8, wherein the indication is received in a radio resource control message.

[0243] Example 10. The user equipment according to any one of Examples 8 to 9, when referring to any one of Examples 6 to 7, wherein the indication includes an incremental MCG configuration, and the incremental MCG configuration indicates that there is no change between the MCG configuration for the first candidate target PSCell and the MCG configuration for the second candidate target PSCell.

[0244] Example 11. A user equipment according to any preceding example, wherein the preparation configuration is a CPC (Conditional PSCell Change) configuration.

[0245] Example 12. The user equipment of any preceding example, wherein the MCG configuration is used to maintain a link to the master node.

[0246] Example 13. The user equipment of any preceding example, wherein the MCG configuration and the SCG configuration include at least one of: a radio link control parameter; a medium access control parameter; a packet data convergence protocol parameter.

[0247] Example 14. A user equipment according to any of the preceding examples, wherein the component is configured to:

[0248] performing a further PSCell change from the first candidate target PSCell to the second candidate target PSCell; and accessing the retained preparation configuration to enable the same MCG configuration to be used for the first candidate target PSCell and the second candidate target PSCell.

[0249] Example 15. A method, comprising: receiving from a master node a preparation configuration for at least a first candidate target PSCell (primary secondary cell) and a second candidate target PSCell, wherein the same MCG (primary cell group) configuration is shared at least between the first candidate target PSCell and the second candidate target PSCell; performing a PSCell change from a source PSCell to the first candidate target PSCell; and retaining the preparation configuration after the PSCell change, wherein the PSCell change is performed without a PCell change.

[0250] Example 16. A computer program, comprising program instructions, which, when executed by a user equipment, cause the user equipment to at least perform: receiving a preparation configuration for at least a first candidate target PSCell (primary secondary cell) and a second candidate target PSCell from a master node, wherein the same MCG (master cell group) configuration is shared at least between the first candidate target PSCell and the second candidate target PSCell; performing a PSCell change from a source PSCell to the first candidate target PSCell; and retaining the preparation configuration after the PSCell change, wherein the PSCell change is performed without a PCell change.

[0251] Example 17. A master node, comprising components for: requesting configuration information from at least a first candidate target secondary node associated with a first candidate target PSCell and at least a second candidate target secondary node associated with a second candidate target PSCell; receiving the requested configuration information; and transmitting to a user equipment a prepared configuration for at least the first candidate target PSCell (primary secondary cell) and the second candidate target PSCell, wherein the same MCG (primary cell group) configuration is shared between at least the first candidate target PSCell and the second candidate target PSCell.

[0252] Example 18. A method, comprising: requesting configuration information from at least a first candidate target secondary node associated with a first candidate target PSCell and at least a second candidate target secondary node associated with a second candidate target PSCell; receiving the requested configuration information, and; transmitting to a user equipment a prepared configuration for at least the first candidate target PSCell (primary secondary cell) and the second candidate target PSCell, wherein the same MCG (primary cell group) configuration is shared at least between the first candidate target PSCell and the second candidate target PSCell.

[0253] Example 19. A computer program, comprising program instructions, which, when executed by a master node, cause the master node to at least perform: requesting configuration information from at least a first candidate target secondary node associated with a first candidate target PSCell and at least a second candidate target secondary node associated with a second candidate target PSCell; receiving the requested configuration information; and transmitting to a user equipment a prepared configuration for at least the first candidate target PSCell (primary secondary cell) and the second candidate target PSCell, wherein the same MCG (primary cell group) configuration is shared at least between the first candidate target PSCell and the second candidate target PSCell.

[0254] The computer program instructions may be included in a computer program, a non-transitory computer readable medium, a computer program product, a machine readable medium. In some but not necessarily all examples, the computer program instructions may be distributed over more than one computer program.

[0255] Although memory 1004 is shown as a single component / circuit, it may be implemented as one or more separate components / circuit, some or all of which may be integrated / removable and / or may provide permanent / semi-permanent / dynamic / cached storage.

[0256] Although processor 1002 is shown as a single component / circuit, it may be implemented as one or more separate components / circuit, some or all of which may be integrated / removable.Processor 1002 may be a single-core or multi-core processor.

[0257] The term "comprising" is used in this document in an inclusive rather than exclusive sense. That is, any reference to X comprising Y indicates that X may comprise only one Y or may comprise more than one Y. If "comprising" is intended to be used in an exclusive sense, it will be clarified in the context by reference to "comprising only one ..." or by the use of "consisting of ..."

[0258] In this specification, the words "connected", "coupled", and "in communication" and their derivatives mean operatively connected / coupled / in communication. It should be appreciated that any number or combination of intervening components (including no intervening components) may be present, i.e., to provide direct or indirect connections / couplings / in communication. Any such intervening components may include hardware and / or software components.

[0259] As used herein, the term "determine / will determine" (and grammatical variations thereof) may include, but not limited to: computing, calculating, processing, deriving, measuring, investigating, identifying, looking up (e.g., looking up a table, a database, or another data structure), ascertaining, etc. In addition, "determining" may include receiving (e.g., receiving information), accessing (e.g., accessing data in a memory), obtaining, etc. In addition, "determining / will determine" may include resolving, selecting, choosing, establishing, etc.

[0260] In this specification, reference has been made to various examples. The description of features or functions of an example indicates that those features or functions are present in the example. The use of the term "example" or "for example" or "may" or "can" herein indicates that such features or functions are present at least in the described example, whether clearly stated or not, and whether described as an example or not, they can but not necessarily be present in some or all other examples. Therefore, "example", "for example", "may" or "can" refers to a specific instance in a class of examples. The attributes of an instance can be attributes unique to the instance, attributes of the class, or attributes of a subclass in the class, which includes some but not all instances in the class. Therefore, it is implicitly disclosed that if a feature is described with reference to an example, but not with reference to another example, then, if possible, this feature may be used in that other example as part of a working combination, but it is not necessarily used in that other example.

[0261] Although examples have been described in the preceding paragraphs with reference to various examples, it should be appreciated that modifications can be made to the examples given without departing from the scope of the claims.

[0262] Features described in the preceding description may be used in combinations other than those described above.

[0263] Although functions have been described with reference to certain features, those functions may be performable by other features whether described or not.

[0264] Although features have been described with reference to certain examples, those features may also be present in other examples whether described or not.

[0265] The terms "a", "an" or "the" as used in this document have an inclusive, rather than an exclusive, meaning. That is, any reference to X that includes one / the Y indicates that X may include only one Y, or may include more than one Y, unless the context clearly indicates otherwise. If the use of "a" or "the" with an exclusive meaning is intended, it will be clarified by the context. In some cases, the use of 'at least one' or 'one or more' may be used to emphasize the inclusive meaning, but the absence of these terms should not be used to infer any exclusive meaning.

[0266] The presence of a feature (or combination of features) in a claim is a reference to that feature or (combination of features) itself and also refers to features that achieve substantially the same technical effect (equivalent features). Equivalent features include, for example, features that are variants and achieve substantially the same result in substantially the same way. Equivalent features include, for example, features that perform substantially the same function in substantially the same way to achieve substantially the same result.

[0267] In this specification, reference has been made to various examples using adjectives or adjective phrases to describe characteristics of examples. Such descriptions of characteristics of examples indicate that the characteristics exist in some examples exactly as described above, and in other examples substantially as described.

[0268] The above description describes some examples of the present disclosure, however, those of ordinary skill in the art will be aware of possible alternative structures and method features that provide equivalent functionality to the specific examples of such structures and features described above herein, and for the sake of brevity and clarity, these structures and features have been omitted from the above description. Nevertheless, the above description should be interpreted as implicitly including references to such alternative structures and method features that provide equivalent functionality, unless such alternative structures or method features are explicitly excluded in the above description of the examples of the present disclosure.

[0269] Even though an effort has been made in the foregoing description to draw attention to those features regarded as important, it should be understood that the applicant may seek protection by way of claims relative to any patented feature or combination of features mentioned previously and / or shown in the drawings, whether or not emphasis has been set forth thereon.

Claims

1. A user equipment comprising components for: receiving, from the master node, a preparation configuration for at least a first candidate target PSCell (primary secondary cell) and a second candidate target PSCell, wherein the same MCG (primary cell group) configuration is shared at least between the first candidate target PSCell and the second candidate target PSCell; performing a PSCell change from a source PSCell to the first candidate target PSCell; as well as The prepared configuration is retained after the PSCell change, wherein the PSCell change is performed without a PCell change. 2 . The user equipment according to claim 1 , wherein the prepared configuration for each candidate target PSCell comprises a complete SCG (Secondary Cell Group) configuration of the corresponding candidate target PSCell.

3. A user equipment according to claim 1, wherein the preparation configuration is associated with a reference SCG (secondary cell group) configuration, and the preparation configuration includes an incremental SCG configuration for each candidate target PSCell, wherein the corresponding incremental SCG configuration indicates the difference between the reference SCG configuration and the SCG configuration of the corresponding candidate target PSCell.

4. The user equipment according to any one of claims 1 to 3, wherein the preparation configuration is associated with a complete MCG configuration shared between at least the first candidate target PSCell and the second candidate target PSCell.

5. A user equipment according to any one of claims 1 to 3, wherein the preparation configuration includes a complete MCG configuration for the corresponding candidate target PSCell, wherein the complete MCG configuration is the same at least for the first candidate target PSCell and the second candidate target PSCell.

6. A user equipment according to any one of claims 1 to 3, wherein the preparation configuration is associated with a reference MCG configuration, and the preparation configuration includes an incremental MCG configuration for a corresponding candidate target PSCell, wherein the corresponding incremental MCG configuration indicates the difference between the reference MCG configuration and the MCG configuration of the corresponding candidate target PSCell, and wherein the MCG configuration shared between at least a first candidate target PSCell and the second candidate target PSCell is the reference MCG configuration.

7. The user equipment according to claim 6, wherein the reference MCG configuration comprises the MCG configuration applicable to the source PSCell.

8. A user equipment according to any preceding claim, further comprising: Receive an indication that the same MCG configuration is shared between at least the first candidate target PSCell and the second candidate target PSCell.

9. The user equipment of claim 8, wherein the indication is received in a radio resource control message.

10. A user equipment according to any one of claims 8 to 9, when relating to any one of claims 6 to 7, wherein the indication comprises an incremental MCG configuration, the incremental MCG configuration indicating that there is no change between the MCG configuration for the first candidate target PSCell and the MCG configuration for the second candidate target PSCell.

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