Apparatus and method of communication

Abstract

The embodiment of the invention relates to a communication device and method. In one aspect, after determining that the subsequent CPAC is performed, the terminal device determines whether a bearer type for the DRB is changed for the subsequent CPAC. If the bearer type is changed, the terminal device performs L2 processing. In this manner, during subsequent CPAC, the terminal device may perform L2 processing in the event of a change in bearer type without explicit indications from the network. Therefore, lossless support can be carried out for AM DRB.

Description

Technical Field

[0001] Embodiments of this disclosure generally relate to the field of telecommunications, and particularly to apparatus and methods for communications with conditional cell change. Background Technology

[0002] For Conditional Primary / Secondary Cell Addition or Change (CPAC) in 3GPP Release 17, terminal devices configured with CPAC must release the CPAC configuration upon completing random access to the target PSCell. Therefore, without prior CPAC reconfiguration and reinitialization from the network side, terminal devices have no opportunity to execute subsequent CPAC. This increases latency for cell changes and signaling overhead, especially when operating in Frequency Range 2 (FR2) with frequent Secondary Cell Group (SCG) changes. Therefore, Multiple Random Access Technology Dual Connectivity (MR-DC) with Selective Cell Group Activation aims to enable subsequent CPAC after an SCG change without requiring reconfiguration and reinitialization from the network side regarding CPAC preparation. This reduces signaling overhead and downtime for SCG changes. However, the solution for subsequent CPAC remains incomplete and requires further development. Summary of the Invention

[0003] In general, embodiments of this disclosure provide methods, apparatus, and computer storage media for communication of subsequent conditional cell changes.

[0004] In a first aspect, a terminal device is provided. The terminal device includes a processor configured to cause the terminal device to: determine that a subsequent CPAC is performed; and, based on the determination that the subsequent CPAC has been changed for a bearer type for a Data Radio Bearer (DRB), perform a first operation comprising at least one of: reconstructing a Packet Data Convergence Protocol (PDCP) entity of the DRB; configuring an encryption algorithm and key for the PDCP entity based on a determination that the PDCP entity of the DRB is not configured with encryption disabled, the encryption algorithm and key being used for encrypting data associated with a master key or a secondary key; configuring an integrity protection algorithm and key for the PDCP entity based on a determination that the PDCP entity of the DRB is configured with integrity protection, the integrity protection algorithm and key being used for integrity protection of data associated with a master key or a secondary key; or reconstructing at least one RLC entity for at least one Radio Link Control (RLC) bearer associated with the DRB.

[0005] In a second aspect, a terminal device is provided. The terminal device includes a processor configured to: determine that a subsequent conditional PSCell change (CPC) is to be performed from a first cell to a second cell; and, based on the determination that the first cell is not a candidate PSCell for the subsequent CPC, perform an operation including one of: determining, by determining a first identifier value as the identifier value of the serving cell and comparing the first identifier value with a second identifier value for the second cell, that the subsequent CPC is an inter-sub-node (SN) subsequent CPC or an intra-SN subsequent CPC; determining that the subsequent CPC is an inter-SN subsequent CPC; and determining that the subsequent CPC is an intra-SN subsequent CPC.

[0006] In a third aspect, a terminal device is provided. The terminal device includes a processor configured to: receive from a master node (MN) a first configuration of a subsequent CPC associated with a first candidate PSCell of a candidate SN, the first configuration including a set of configurations, the configurations in the set including a primary cell group (MCG) configuration, wherein the MCG configuration includes execution conditions for subsequent CPCs for a set from the first candidate PSCell to the second candidate PSCell, or wherein the first configuration further includes execution conditions for subsequent CPCs for a set from the first candidate PSCell to the second candidate PSCell.

[0007] In a fourth aspect, a master node is provided. The master node includes a processor configured to cause the master node to: transmit to an end device a first configuration of a subsequent CPC associated with a first candidate PSCell of a candidate SN, the first configuration including a set of configurations, the configurations in the set including an MCG configuration, wherein the MCG configuration includes execution conditions for subsequent CPCs for a set from the first candidate PSCell to the second candidate PSCell, or wherein the first configuration further includes execution conditions for subsequent CPCs for a set from the first candidate PSCell to the second candidate PSCell.

[0008] In a fifth aspect, a method of communication is provided. The method includes: determining at a terminal device that a subsequent CPAC is executed; and performing a first operation based on the determination that the subsequent CPAC has been changed for a bearer type associated with a DRB, the first operation including at least one of the following: reconstructing a PDCP entity of the DRB; configuring an encryption algorithm and key for the PDCP entity for encryption of data associated with a master key or a secondary key, based on the determination that the PDCP entity of the DRB is not configured with encryption disabled; configuring an integrity protection algorithm and key for the PDCP entity for integrity protection of data associated with a master key or a secondary key, based on the determination that the PDCP entity of the DRB is configured with integrity protection; or reconstructing at least one RLC entity for at least one RLC bearer associated with the DRB.

[0009] In a sixth aspect, a method of communication is provided. The method includes: determining at a terminal device that a subsequent CPC is to be executed from a first cell to a second cell; and, based on the determination that the first cell is not a candidate PSCell for the subsequent CPC, performing an operation comprising: determining, by determining a first identifier value as the identifier value of the serving cell and comparing the first identifier value with a second identifier value for the second cell, whether the subsequent CPC is an inter-SN subsequent CPC or an intra-SN subsequent CPC; determining that the subsequent CPC is an inter-SN subsequent CPC; and determining that the subsequent CPC is an intra-SN subsequent CPC.

[0010] In a seventh aspect, a method of communication is provided. The method includes: receiving, at a terminal device, a first configuration of a subsequent CPC associated with a first candidate PSCell of a candidate SN, from an MN. The first configuration includes a set of configurations, the configurations in the set of configurations including an MCG configuration, wherein the MCG configuration includes execution conditions for subsequent CPCs for a set of subsequent CPCs from the first candidate PSCell to the second candidate PSCell, or wherein the first configuration further includes execution conditions for subsequent CPCs for a set of subsequent CPCs from the first candidate PSCell to the second candidate PSCell.

[0011] In an eighth aspect, a method of communication is provided. The method includes: transmitting, at a master node, a first configuration of a subsequent CPC associated with a first candidate PSCell of a candidate SN to an end device, the first configuration including a set of configurations, the configurations in the set including an MCG configuration, wherein the MCG configuration includes execution conditions for subsequent CPCs for a set of subsequent CPCs from the first candidate PSCell to the second candidate PSCell, or wherein the first configuration further includes execution conditions for subsequent CPCs for a set of subsequent CPCs from the first candidate PSCell to the second candidate PSCell.

[0012] In a ninth aspect, a computer-readable medium is provided having instructions stored thereon. When executed on at least one processor, the instructions cause the at least one processor to perform the method according to any one of the fifth to eighth aspects of this disclosure.

[0013] Other features of this disclosure will become readily apparent from the following description. Attached Figure Description

[0014] The above and other objects, features, and advantages of this disclosure will become more apparent from the more detailed description of some embodiments of this disclosure in the accompanying drawings, wherein:

[0015] Figure 1 The illustration shows an example communication environment in which some embodiments of the present disclosure may be implemented;

[0016] Figure 2 The illustration shows an example process of subsequent CPAC according to an embodiment of the present disclosure;

[0017] Figure 3 The illustration shows an example process of subsequent CPC according to an embodiment of the present disclosure;

[0018] Figure 4 The illustration shows another example process of subsequent CPAC according to an embodiment of the present disclosure;

[0019] Figure 5 The illustration shows example methods of communication implemented at a terminal device according to some embodiments of the present disclosure;

[0020] Figure 6 The illustration shows another example method of communication implemented at a terminal device according to some embodiments of the present disclosure;

[0021] Figure 7 The illustration shows yet another example method of communication implemented at a terminal device according to some embodiments of the present disclosure;

[0022] Figure 8 The illustrations depict example methods of communication implemented at the master node according to some embodiments of the present disclosure; and

[0023] Figure 9 A simplified block diagram of an apparatus suitable for implementing embodiments of the present disclosure is shown.

[0024] Throughout the accompanying drawings, the same or similar reference numerals denote the same or similar elements. Detailed Implementation

[0025] The principles of this disclosure will now be described with reference to some embodiments. It should be understood that these embodiments are described for illustrative purposes only and to help those skilled in the art understand and implement this disclosure, and do not imply any limitation on the scope of this disclosure. This disclosure described herein can be implemented in various ways other than those described below.

[0026] In the following description and claims, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains.

[0027] As used herein, the term 'terminal device' refers to any device with wireless or wired communication capabilities. Examples of terminal devices include, but are not limited to, user equipment (UE), personal computers, desktop computers, mobile phones, cellular phones, smartphones, personal digital assistants (PDAs), laptops, tablets, wearable devices, Internet of Things (IoT) devices, ultra-reliable low-latency communication (URLLC) devices, Internet of Everything (IoE) devices, machine-type communication (MTC) devices, vehicular equipment for V2X communication (where X represents a pedestrian, vehicle, or infrastructure / network), devices for integrated access and backhaul (IAB), small data transmission (SDT), mobility, multicast and broadcast services (MBS), location, dynamic / flexible duplex in commercial networks, and capabilities. The term "terminal device" can refer to various types of real-world applications, including RedCap, spacecraft or airborne vehicles in non-terrestrial networks (NTNs) (including satellites and high-altitude platforms (HAPs) encompassing unmanned aerial systems (UAS), extended reality (XR) devices (including different types of reality such as augmented reality (AR), mixed reality (MR), and virtual reality (VR)), unmanned aerial vehicles (UAVs) commonly referred to as drones (aircraft without any human pilots), devices on high-speed trains (HSTs), or image capture devices (such as digital cameras), sensors, gaming devices, music storage and playback devices, or internet devices enabling wireless or wired internet access and browsing. A 'terminal device' can also have 'multicast / broadcast' characteristics to support public safety and mission-critical applications, V2X applications, transparent IPv4 / IPv6 multicast delivery, IPTV, smart TV, wireless services, wireless software delivery, group communications, and IoT applications. It can also include one or more Subscriber Identity Modules (SIMs) (referred to as multiSIMs). The term "terminal device" can be used interchangeably with UE, mobile station, subscriber station, mobile terminal, user terminal, or wireless device.

[0028] The term "network device" refers to a device that provides or hosts a cell or coverage area in which terminal devices can communicate. Examples of network devices include, but are not limited to, NodeB (or NB), evolved NodeB (eNodeB or eNB), next-generation NodeB (gNB), Transmitter Receiver Point (TRP), Remote Radio Unit (RRU), Radio Head (RH), Remote Radio Head (RRH), IAB node, low-power node (such as femtonode, piconode), reconfigurable smart surface (RIS), network-controlled repeater, etc.

[0029] Terminal devices or network devices can have artificial intelligence (AI) or machine learning capabilities. This typically includes a model that is trained on a specific function from a large amount of collected data and can be used to predict certain information.

[0030] Terminal or network devices can operate on several frequency ranges, such as FR1 (410 MHz to 7125 MHz), FR2 (24.25 GHz to 71 GHz), bands greater than 100 GHz, and terahertz (THz). They can also operate on licensed / unlicensed / shared spectrum. In MR-DC applications, terminal devices can have more than one connection to network devices. Terminal or network devices can operate in full-duplex, flexible-duplex, and cross-frequency division duplex modes.

[0031] Network devices can feature network energy saving and self-organizing network (SON) / minimal driving test (MDT) capabilities. Terminals can have power-saving features.

[0032] The embodiments of this disclosure can be executed in test equipment, such as signal generators, signal analyzers, spectrum analyzers, network analyzers, test terminal equipment, test network equipment, and channel simulators.

[0033] In one embodiment, the terminal device can be connected to a first network device and a second network device. One of the first and second network devices can be a master node, and the other a slave node. The first and second network devices can use different Radio Access Technologies (RATs). In one embodiment, the first network device can be a first RAT device, and the second network device can be a second RAT device. In one embodiment, the first RAT device is an eNB, and the second RAT device is a gNB. Information related to different RATs can be transmitted to the terminal device from at least one of the first or second network devices. In one embodiment, first information can be transmitted from the first network device to the terminal device, and second information can be transmitted directly or via the first network device from the second network device to the terminal device. In one embodiment, information related to the configuration of the terminal device configured by the second network device can be transmitted via the first network device from the second network device. Information related to the reconfiguration of the terminal device configured by the second network device can be transmitted directly or via the first network device from the second network device to the terminal device.

[0034] As used herein, unless the context explicitly indicates otherwise, the singular forms 'a', 'an', and 'the' are intended to include the plural forms as well. The term 'including' and its variations will be understood as open terms meaning 'including but not limited to'. The term 'based on' will be understood as 'at least partially based on'. The terms 'one embodiment' and 'embodiment' will be understood as 'at least one embodiment'. The term 'another embodiment' will be understood as 'at least one other embodiment'. The terms 'first', 'second', etc., may refer to different or the same objects. Other explicit and implicit definitions may be included below.

[0035] In some examples, values, processes, or devices are referred to as 'best,' 'lowest,' 'highest,' 'minimum,' 'maximum,' etc. It will be understood that such descriptions are intended to indicate that a choice can be made among many functional alternatives used, and that such a choice does not need to be better, smaller, higher, or otherwise preferred than other choices.

[0036] In the context of this disclosure, the term "cell change or addition" may be used interchangeably with "reconfigurationWithSync for SCG or MCG". In the context of this disclosure, the term "subsequent CPAC" may be used interchangeably with "selective activation of cell group", "selective activation of PSCell (SAP)", "subsequent CPA / CPC", "conditional selective cell group" or "conditional subsequent cell change".

[0037] In the context of this disclosure, the term "PSCell" refers to the SpCell of the SCG, the term "PCell" refers to the SpCell of the MCG, and the term "SpCell" refers to the primary cell of the SCG or MCG. The term "prepared PSCell" may be used interchangeably with "candidate PSCell," "candidate cell," or "prepared candidate PSCell."

[0038] In the context of this disclosure, the term "bearer type of radio bearer" can include MN-terminated bearer or SN-terminated bearer. An MN-terminated bearer can refer to a radio bearer for which the PDCP resides in an MN. An SN-terminated bearer can refer to a radio bearer for which the PDCP resides in an SN.

[0039] Recently, it has been agreed that for selective activation of the SCG initiated by both the SN and MN, the candidate SN will generate execution conditions for subsequent CPCs. However, it remains unclear how to support the generation of execution conditions for subsequent CPCs for selective activation of the SCG initiated by the SN. Furthermore, it has been agreed to support updating security key counters based on multiple pre-configured security key counters with inter-SN mobility. However, it remains unclear when the security key counters need to be changed.

[0040] In view of this, embodiments of the present disclosure provide a solution for communication during subsequent CPAC to overcome the above and other potential problems. In one aspect, after determining that a subsequent CPAC is to be performed, the terminal device determines whether the bearer type for the DRB has been changed for the subsequent CPAC. If the bearer type has been changed, the terminal device performs a first operation, the first operation including at least one of the following: reconstructing the PDCP entity of the DRB; configuring an encryption algorithm and key for the PDCP entity based on a determination that the PDCP entity of the DRB is not configured with encryption disabled, the encryption algorithm and key being used for encryption of data associated with a master key or a secondary key; configuring an integrity protection algorithm and key for the PDCP entity based on a determination that the PDCP entity of the DRB is configured with integrity protection, the integrity protection algorithm and key being used for integrity protection of data associated with a master key or a secondary key; or reconstructing at least one RLC entity for at least one RLC bearer associated with the DRB. In this way, during subsequent CPAC, the terminal device can perform Layer 2 (L2) processing without explicit indication from the network if the bearer type changes. Therefore, lossless support can be provided for acknowledged mode (AM) DRBs.

[0041] In another aspect, after determining that the subsequent CPC will be executed from the first cell to the second cell, the terminal device determines whether the first cell is a candidate PSCell for the subsequent CPC. If the first cell is not a candidate PSCell for the subsequent CPC, the terminal device performs an operation including one of the following: determining whether the subsequent CPC is an inter-SN subsequent CPC or an intra-SN subsequent CPC by determining a first identifier value as the identifier value of the serving cell and comparing the first identifier value with a second identifier value for the second cell; determining that the subsequent CPC is an inter-SN subsequent CPC; and determining that the subsequent CPC is an intra-SN subsequent CPC. In this way, during the subsequent CPAC, the terminal device can identify intra-SN subsequent CPCs and inter-SN subsequent CPCs. This can facilitate different behaviors in security key updates and L2 processing for the cases of intra-SN subsequent CPCs and inter-SN subsequent CPCs.

[0042] In another aspect, the terminal device receives from the MN a first configuration for subsequent CPCs associated with a first candidate PSCell of the candidate SN. The first configuration includes a set of configurations. The configurations in the set of configurations include an MCG configuration. The MCG configuration includes execution conditions for subsequent CPCs for a set from the first candidate PSCell to the second candidate PSCell, or the first configuration further includes execution conditions for subsequent CPCs for a set from the first candidate PSCell to the second candidate PSCell. In this way, it is possible to support the generation of execution conditions for subsequent CPCs by the candidate SN.

[0043] The principles and implementation of this disclosure will now be described in detail with reference to the accompanying drawings.

[0044] It will be understood that this solution can be applied to SCG changes as well as MCG changes. That is, this solution can be applied to subsequent CPCs or subsequent conditional handovers. Subsequent CPCs or subsequent conditional handovers can also be referred to as selective activation of cell groups, selective activation of SCGs, subsequent SCG changes, subsequent cell group changes, or subsequent conditional cell changes. For convenience, embodiments of this disclosure will be described using subsequent CPCs as an example. Examples of communication networks

[0045] Figure 1 The illustration shows a schematic diagram of an example communication environment 100 in which embodiments of the present disclosure may be implemented. For example... Figure 1 As shown, the communication environment 100 may include a network device 110 and a terminal device 120. The network device 110 provides a cell 111, and the terminal device 120 is located in the cell 111 and is served by the network device 110.

[0046] The communication environment 100 may also include one or more other network devices, such as network devices 130, 140, and 150. Network device 130 provides cells 131, 132, and 133. Network device 140 provides cells 141, 142, and 143, and network device 150 provides cells 151, 152, and 153. It should be noted that the number of cells is not limited to three, and more or fewer cells may be provided by network devices 130, 140, and 150.

[0047] Assume that terminal device 120 can establish dual connections (i.e., simultaneous connections) with two network devices. For example, network device 110 can act as the MN (hereinafter also referred to as MN 110 for convenience), and network device 130 can act as the SN (hereinafter also referred to as SN 130 for convenience). Although only cell 111 is shown, MN 110 can provide multiple cells, and these cells can form an MCG for terminal device 120. Assume that cell 111 is the primary cell (i.e., PCell) in the MCG. Furthermore, cells 131, 132, and 133 provided by network device 130 can form an SCG for terminal device 120. Assume that cell 131 is the primary cell (i.e., PSCell) in the SCG.

[0048] SN 130 can communicate with terminal device 120 via a channel such as a wireless communication channel. Similarly, MN 110 can also communicate with terminal device 120 via a channel such as a wireless communication channel. SN 130 can communicate with MN 110 via the Xn interface.

[0049] It should be understood that Figure 1 The number of devices or cells mentioned is given for illustrative purposes and does not imply any limitation on this disclosure. The communication environment 100 may involve any suitable number of network devices and / or terminal devices and / or cells suitable for implementing the present disclosure.

[0050] The communications in the communication environment 100 can conform to any suitable standard, including but not limited to Global System for Mobile Communications (GSM), Long Term Evolution (LTE), LTE Evolution, LTE-A Advanced, Wideband Code Division Multiple Access (WCDMA), Code Division Multiple Access (CDMA), GSM EDGE Radio Access Network (GERAN), Machine Type Communication (MTC), etc. Embodiments of this disclosure can be implemented according to any generation of communication protocols currently known or to be developed in the future. Examples of communication protocols include, but are not limited to, first-generation (1G), second-generation (2G), 2.5G, 2.75G, third-generation (3G), fourth-generation (4G), 4.5G, fifth-generation (5G) communication protocols, 5.5G, 5G Advanced networks, or sixth-generation (6G) networks.

[0051] In some embodiments, network device 110 may configure terminal device 120 to support conditional reconfiguration of subsequent CPAC.

[0052] Assume cells 131-133, 141-143, and 151-153 are configured as candidate cells for terminal device 120. In some scenarios, terminal device 120 may initially communicate only with network device 110. As terminal device 120 moves, when conditions for candidate cells (e.g., cell 131) are met, terminal device 120 can be enabled to establish dual connectivity with both network devices 110 and 130. This SN addition process can be referred to as Conditional PSCell Addition (CPA).

[0053] In some scenarios, terminal device 120 can establish dual connections with network devices 110 and 130. Network device 110 acts as the MN, and network device 130 acts as the SN. As terminal device 120 moves, the SN serving terminal device 120 can be changed from network device 130 (hereinafter also referred to as the source SN or current SN 130) to network device 140 (hereinafter also referred to as the target SN 140). This PSCell change process can be referred to as CPC.

[0054] In some scenarios, after a terminal device is configured with conditional reconfiguration and an enabled subsequent CPC, and before at least one execution condition is met for any candidate PSCell, terminal device 120 can receive a Radio Resource Control (RRC) reconfiguration message containing reconfigurationWithSync for SCG from network device 110, and terminal device 120 can accordingly perform a PSCell change or addition. This process is called a conventional PSCell change or addition. For example, after a conventional PSCell change or addition process, the SN serving terminal device 120 is network device 140.

[0055] Following the aforementioned CPA, CPC, or traditional PSCell change or addition process, terminal device 120 does not release conditional reconfiguration support for subsequent CPACs and continues to perform conditional reconfiguration evaluation. As terminal device 120 moves further, when the conditions for another candidate cell (e.g., cell 151) are met, the SN serving terminal device 120 can be changed from network device 140 to network device 150 (hereinafter also referred to as target SN 150). This SN change process can be referred to as subsequent CPCs.

[0056] like Figure 1As shown, as terminal device 120 moves further, it can move out of the coverage area of ​​the SN. Network device 110 (i.e., MN) can instruct terminal device 120 to release the previous SN (e.g., network device 150). In this case, terminal device 120 may not release the conditional reconfiguration supporting subsequent CPAC and may continue to perform conditional reconfiguration evaluation for subsequent CPA.

[0057] Continue to refer to Figure 1 As terminal device 120 moves further, when the conditions for a candidate cell (e.g., cell 141) are met, terminal device 120 can be enabled to establish dual connectivity with network device 110 and network device 140. This process can be referred to as subsequent CPA.

[0058] Embodiments of this disclosure provide solutions for subsequent CPAC communication to enhance the subsequent CPAC process. These solutions will be described below in conjunction with... Figures 2 to 4 Described. Example implementation of L2 processing

[0059] In some cases, the bearer type of the DRB may or may not be changed during subsequent CPAC. Whether the bearer type is changed or not, different L2 processing (e.g., PDCP reconstruction or recovery, or RLC reconstruction) needs to be performed. However, for candidate PSCells, whether the bearer type is changed or not depends on the terminal device's movement trajectory for subsequent CPAC. Therefore, L2 processing cannot be configured in RRC signaling as in traditional CPAC.

[0060] In view of this, embodiments of this disclosure provide a solution for L2 processing of subsequent CPAC. This solution will be described below in conjunction with... Figure 2 Described. Figure 2 The illustration shows an example process 200 of a subsequent CPAC according to an embodiment of the present disclosure. For discussion purposes, process 200 will be referred to... Figure 1 The process 200 may involve terminal device 120 and network device 110. In this example, network device 110 is the MN serving terminal device 120.

[0061] like Figure 2 As shown, terminal device 120 can determine 210 that a subsequent CPAC will be executed. In some embodiments, network device 110 can transmit 211 a configuration (e.g., conditional reconfiguration) for the subsequent CPAC to terminal device 120, which includes execution conditions for the subsequent CPAC to the set of candidate PSCells. Terminal device 120 can perform 212 a conditional reconfiguration evaluation based on the execution conditions.

[0062] In some embodiments, after a CPA, CPC, or conventional PSCell change or addition process, the terminal device 120 may determine that a subsequent CPC will be executed when the execution conditions for a candidate PSCell (e.g., cell 142) are met. In some embodiments, after a CPA, CPC, or conventional PSCell change or addition process, the terminal device 120 may determine that a subsequent CPA will be executed when the execution conditions for a candidate PSCell (e.g., cell 141) are met after the SN is released.

[0063] After determining that a subsequent CPAC has been executed, terminal device 120 can determine whether the bearer type of a DRB has been changed by 220 for the subsequent CPAC. In other words, after the execution of a subsequent CPAC, terminal device 120 can determine whether the bearer type of a DRB has been changed.

[0064] In some embodiments, a change in bearer type may include a change from an MN-terminated bearer to an SN-terminated bearer.

[0065] In some embodiments, terminal device 120 may determine whether the bearer type for the DRB has been changed based on the key to be used for the DRB (e.g., keyToUse associated with the DRB). In some embodiments, if the key to be used for the DRB has been changed, terminal device 120 may determine that the bearer type for the DRB has been changed. If the key to be used for the DRB has not been changed, terminal device 120 may determine that the bearer type for the DRB has not been changed. For example, if the key to be used for the DRB is changed from primary to secondary, or from secondary to primary, terminal device 120 may determine that the bearer type for the DRB has been changed. Otherwise, terminal device 120 may determine that the key to be used for the DRB has not been changed.

[0066] Continue to refer to Figure 2 If the bearer type for the DRB is changed, the terminal device 120 may perform 230 L2 processing (also referred to herein as the first operation). In some embodiments, if the bearer type for the DRB is changed, the terminal device 120 may reconstruct the PDCP entity of the DRB.

[0067] In some embodiments, if the bearer type for the DRB is changed, and if the PDCP entity of the DRB is not configured with encryption disabled, the terminal device 120 can configure an encryption algorithm and key for the PDCP entity of the DRB. The encryption algorithm and key are used to encrypt data associated with a master key or a secondary key. The master key or secondary key can be indicated in the key to be used for the DRB (e.g., keyToUse). That is, the encryption configuration can be applied to all subsequent PDCP protocol data units (PDUs) received and transmitted by the terminal device 120.

[0068] In some embodiments, if the bearer type for the DRB is changed, and if the PDCP entity of the DRB is configured with integrity protection, the terminal device 120 can configure an integrity protection algorithm and key for the PDCP entity. The integrity protection algorithm and key are used for integrity protection of data associated with a master key or a secondary key. The master key or secondary key may be indicated in the key to be used for the DRB (e.g., keyToUse).

[0069] In some embodiments, if the bearer type for the DRB is changed, the terminal device 120 can reconstruct at least one RLC entity for at least one RLC bearer associated with the DRB. It should be noted that the above operations when the DRB bearer type is changed can be performed individually or in any combination.

[0070] Continue to refer to Figure 2 If the bearer type for the DRB has not been changed, the terminal device 120 may perform 240 L2 processing (also referred to herein as the second operation). In some embodiments, if the bearer type for the DRB has not been changed, the terminal device 120 may trigger the PDCP entity of the DRB to perform data recovery. In some embodiments, if the bearer type for the DRB has not been changed, the terminal device 120 may rebuild at least one RLC entity for at least one SCG RLC bearer associated with the DRB.

[0071] In some embodiments, network device 110 may limit or avoid bearer type changes during subsequent CPAC based on appropriate configuration.

[0072] Using process 200, during subsequent CPAC, the terminal device can perform L2 processing even if the bearer type changes without explicit instructions from the network. Therefore, lossless support for AM DRB is possible. Example implementation of SN-to-SN or subsequent CPC

[0073] In some cases, whether the terminal device performs security key updates and L2 processing during a subsequent CPC depends on whether the subsequent CPC is an inter-SN subsequent CPC or an intra-SN subsequent CPC. However, it is currently unclear how to determine whether a subsequent CPC is an inter-SN subsequent CPC or an intra-SN subsequent CPC, and what L2 processing should be performed for inter-SN subsequent CPCs or intra-SN subsequent CPCs.

[0074] In view of this, embodiments of this disclosure provide a solution for subsequent CPC security key updates and L2 processing. This solution will be described below in conjunction with... Figure 3 Described. Figure 3 The illustration depicts an example process 300 of a subsequent CPC according to an embodiment of the present disclosure. For purposes of discussion, process 300 will be referred to... Figure 1 The process 300 may involve terminal device 120 and network device 110. In this example, network device 110 is the MN serving terminal device 120.

[0075] like Figure 3 As shown, terminal device 120 can determine 310 that a subsequent CPC will be executed from the first cell to the second cell. In some embodiments, network device 110 can transmit 311 a configuration (e.g., conditional reconfiguration) for a subsequent CPAC to terminal device 120, which includes execution conditions for the subsequent CPAC to a set of candidate PSCells. Terminal device 120 can perform 312 a conditional reconfiguration evaluation based on the execution conditions. After a CPA or CPC or a traditional PSCell change or addition process, terminal device 120 is changed to the first cell (e.g., cell 142). When the execution conditions for a candidate PSCell (i.e., the second cell (e.g., cell 151)) are met, terminal device 120 can determine that a subsequent CPC from cell 142 to cell 151 will be executed.

[0076] After determining that a subsequent CPC has been executed, that is, after the execution of the subsequent CPC, the terminal device 120 can determine whether the subsequent CPC is an inter-SN subsequent CPC or an intra-SN subsequent CPC. In some embodiments, this determination may be based on the identifier (ID) value configured by the network device 110 for the target candidate PSCell (i.e., the second cell) and the ID value of the serving PSCell or the source PSCell (i.e., the first cell) maintained by the terminal device 120.

[0077] Continue to refer to Figure 3Terminal device 120 can determine whether the first cell (i.e., the serving PSCell or the source PSCell) is a candidate PSCell for subsequent CPACs. In some embodiments, if the first cell is a candidate PSCell supporting subsequent CPACs, terminal device 120 can set the ID value of the serving cell to the ID value configured for the candidate PSCell. If the first cell is not a candidate PSCell for subsequent CPACs, terminal device 120 can perform operations according to embodiments of this disclosure.

[0078] like Figure 3 As shown, in some embodiments, if the first cell is not a candidate PSCell for subsequent CPACs, the terminal device 120 can determine the first ID value 330 as the ID value of the serving cell.

[0079] In some embodiments, terminal device 120 may receive a configuration of the first ID value 331 from network device 110 (i.e., MN). Alternatively, terminal device 120 may receive a configuration of the first ID value from network device 150 (i.e., target SN). In other words, if the serving PSCell or source PSCell (e.g., cell 142) is not a candidate PSCell, network device 110 may also configure an ID value for the serving PSCell or source PSCell. After receiving this configuration, terminal device 120 may set the ID value maintained for the serving PSCell or source PSCell to the ID value configured by network device 110. In some embodiments, terminal device 110 may maintain the ID value of the serving PSCell or source PSCell in UE variables.

[0080] In some embodiments, the terminal device 120 may set the first ID value 332 as the default value. In other words, if the serving PSCell or the source PSCell is not a candidate PSCell, the terminal device 120 may set the ID value of the serving cell to the default value.

[0081] After determining the first ID value, terminal device 120 can compare the first ID value with the second ID value of the second cell. If the first ID value and the second ID value are the same, terminal device 120 can determine that the subsequent CPC is an intra-SN subsequent CPC. If the first ID value and the second ID value are different, terminal device 120 can determine that the subsequent CPC is an inter-SN subsequent CPC. In other words, if the ID value of the serving PSCell or the source PSCell is the same as the ID value of the target candidate PSCell, terminal device 120 determines that the subsequent CPC is intra-SN. If the ID value of the serving PSCell or the source PSCell is different from the ID value of the target candidate PSCell, terminal device 120 determines that the subsequent CPC is inter-SN.

[0082] In some embodiments, if the subsequent CPC is an inter-SN subsequent CPC, the terminal device 120 may replace the ID value of the serving cell with a second ID value (i.e., the ID value of the target candidate PSCell).

[0083] Continue to refer to Figure 3 In some embodiments, if the first cell (i.e., the serving PSCell or the source PSCell) is not a candidate PSCell for a subsequent CPAC, then the terminal device 120 can determine that the subsequent CPC 350 is an inter-SN subsequent CPC. In some alternative embodiments, if the first cell (i.e., the serving PSCell or the source PSCell) is not a candidate PSCell for a subsequent CPAC, then the terminal device 120 can determine that the subsequent CPC 360 is an intra-SN subsequent CPC.

[0084] In some embodiments, if neither the first cell nor the second cell is configured with an ID value, the terminal device 120 can determine that the subsequent CPC is an inter-SN subsequent CPC. In other words, if at least one of the serving PSCell / source PSCell or the target candidate PSCell is not configured with an ID value, the terminal device 120 can determine that the subsequent CPC is inter-SN. In some alternative embodiments, if neither the first cell nor the second cell is configured with an ID value, the terminal device 120 can determine that the subsequent CPC is intra-SN. In other words, if at least one of the serving PSCell / source PSCell or the target candidate PSCell is not configured with an ID value, the terminal device 120 can determine that the subsequent CPC is intra-SN.

[0085] In some embodiments, for each ID value, network device 110 may configure a list of security key counters (e.g., sk-counter) to derive or update the secondary key. After receiving the list of security key counters, terminal device 120 may store the list of security key counters for each ID value in UE variables. For subsequent CPCs between SNs and within SNs, the terminal device may perform different operations for security key updates and L2 processing.

[0086] Continue to refer to Figure 3If the subsequent CPC is an inter-SN subsequent CPC, the terminal device 120 can perform a 370 security key update. In some embodiments, the terminal device 120 can derive a secondary key by using a security key counter in a list of security key counters associated with a second ID value (i.e., the ID value of the target candidate PSCell). In some embodiments, the terminal device 120 can discard the security key counters used that are associated with the ID value of the target candidate PSCell or the updated ID value of the service PSCell from a stored list of security key counters.

[0087] Continue to refer to Figure 3 If the subsequent CPC is an inter-SN subsequent CPC, then the terminal device 120 can perform 380 L2 processing.

[0088] In some embodiments, for an SN-terminated DRB (e.g., for each SN-terminated DRB), terminal device 120 can reconstruct the PDCP entity of the DRB. An SN-terminated DRB is a DRB with a secondary keyToUse. In some embodiments, if the PDCP entity of the DRB is not configured with encryption disabled, terminal device 120 can configure an encryption algorithm and key for the PDCP entity, which are used to encrypt data associated with the secondary key. That is, the encryption configuration can be applied to all subsequent PDCP PDUs received and transmitted by terminal device 120. In some embodiments, if the PDCP entity of the DRB is configured with integrity protection, terminal device 120 can configure an integrity protection algorithm and key for the PDCP entity, which are used to protect the integrity of data associated with the secondary key. That is, the integrity protection configuration can be applied to all subsequent PDCP PDUs received and transmitted by terminal device 120. In some embodiments, terminal device 120 can reconstruct at least one RLC entity for at least one RLC bearer associated with the DRB. It should be understood that any combination of the above operations is also possible.

[0089] In some embodiments, for at least one signaling radio bearer (SRB) between the SN (e.g., network device 150) corresponding to the second cell (e.g., cell 151) and the terminal device 120 (e.g., for each direct SRB between the SN and the terminal device 120), such as SRB3, the terminal device 120 may reconstruct a PDCP entity for at least one SRB. In some embodiments, the terminal device 120 may configure the PDCP entity to apply an encryption algorithm and key for encrypting RRC signaling associated with a secondary key. That is, the encryption configuration may be applied to all subsequent messages received and transmitted by the terminal device 120, including messages used to indicate the successful completion of the encryption configuration process. In some embodiments, the terminal device 120 may configure the PDCP entity to apply an integrity protection algorithm and key for integrity protection of RRC signaling associated with a secondary key. That is, the integrity protection configuration may be applied to all subsequent messages received and transmitted by the terminal device 120, including messages used to indicate the successful completion of the integrity protection configuration process. In some embodiments, the terminal device 120 may reconstruct at least one RLC entity for at least one RLC bearer associated with at least one SRB. It should be understood that any combination of the above operations is also possible.

[0090] In some embodiments, for an MN-terminated DRB (e.g., for each MN-terminated DRB), the terminal device 120 may reconstruct at least one RLC entity for at least one SCG RLC bearer associated with the MN-terminated DRB. The MN-terminated DRB is a DRB with a primary keyToUse.

[0091] In some embodiments, for an SRB (e.g., for each MCG SRB or direct SRB between the MN (i.e., network device 110) and terminal device 120), such as SRB1 or SRB2, terminal device 120 may reconstruct at least one RLC entity for at least one SCG RLC bearer associated with the SRB. In some embodiments, terminal device 120 may reconstruct RLC entities for all SCG RLC bearers.

[0092] Continue to refer to Figure 3If the subsequent CPC is an intra-SN subsequent CPC, the terminal device 120 can perform 390 L2 processing. In some embodiments, for an SN-terminated DRB (e.g., for each SN-terminated DRB), the terminal device 120 can trigger the PDCP entity of the DRB to perform data recovery. In some embodiments, the terminal device 120 can reconstruct at least one RLC entity for at least one SCG RLC bearer associated with the DRB. The SN-terminated DRB is a DRB with a secondary keyToUse.

[0093] In some embodiments, for an SRB (e.g., for each direct SRB between the SN (e.g., network device 150) and terminal device 120), such as SRB3, terminal device 120 may trigger the PDCP entity of the SRB to perform a Service Data Unit (SDU) drop. In some embodiments, terminal device 120 may reconstruct at least one RLC entity for at least one SCG RLC bearer associated with the SRB.

[0094] In some embodiments, for an MN-terminated DRB (e.g., for each MN-terminated DRB), the terminal device 120 may reconstruct at least one RLC entity for at least one SCG RLC bearer associated with the MN-terminated DRB. The MN-terminated DRB is a DRB with a primary keyToUse.

[0095] In some embodiments, for an SRB (e.g., for each MCG SRB or direct SRB between the MN (i.e., network device 110) and terminal device 120), such as SRB1 or SRB2, terminal device 120 may reconstruct at least one RLC entity for at least one SCG RLC bearer associated with the SRB. In some embodiments, terminal device 120 may reconstruct RLC entities for all SCG RLC bearers.

[0096] In some embodiments, after performing a subsequent CPC, if the serving cell ID value is available, the terminal device 120 may ignore the PDCP reconstruction information elements (IEs) configured for SN termination DRBs and direct SRBs (e.g., SRB3) between the SN and the terminal device 120, such as the PDCP reconstruction IE (e.g., reestablishPDCP IE), the PDCP recovery IE (e.g., recoveryPDCP IE), and the PDCP discard IE (e.g., discardOnPDCP IE). In some embodiments, for MN termination DRBs, the terminal device 120 may reconstruct at least one RLC entity for at least one SCG RLC bearer associated with the DRB. In some embodiments, for MCG SRBs or direct SRBs (e.g., SRB1, SRB2) between the MN and the terminal device 120, the terminal device 120 may reconstruct at least one RLC entity for at least one SCG RLC bearer associated with the SRB. In some embodiments, the terminal device 120 may reconstruct RLC entities for all SCG RLC bearers.

[0097] Using process 300, during subsequent CPAC, the terminal device can perform different behaviors in security key updates and L2 processing depending on whether subsequent CPCs occur within the same SN or between different SNs. Example implementation of execution conditions for subsequent CPCs

[0098] In some scenarios, for subsequent CPACs initiated by the SN, the execution conditions for subsequent CPCs can be generated by the candidate SN. However, it is unclear how to generate the execution conditions for subsequent CPCs.

[0099] In view of this, embodiments of this disclosure provide a solution for configuring execution conditions for subsequent CPAC configurations. This solution will be described below in conjunction with... Figure 4 Described. Figure 4 The illustration shows another example process 400 of a subsequent CPAC according to an embodiment of the present disclosure. For discussion purposes, process 400 will be referred to... Figure 1 The process 400 may involve terminal device 120 and network devices 110 and 140. In this example, network device 110 is the MN serving terminal device 120, and network device 140 is the target candidate SN.

[0100] like Figure 4As shown, network device 110 (i.e., MN) can transmit a SN Add Request message to each candidate SN (e.g., network device 140). The SN Add Request message may include a list of recommended candidate PSCells of the candidate SN and a list of candidate PSCells of other candidate SNs (e.g., network device 150).

[0101] Continue to refer to Figure 4 Network device 140 (i.e., the target candidate SN) can transmit a 420SN Add Request Confirmation Message to network device 110 (i.e., MN). The SN Add Request Confirmation Message may include execution conditions for a subsequent CPC from one candidate PSCell (e.g., cell 142) of the target candidate SN to another candidate PSCell (e.g., cell 143) of the target candidate SN or another candidate PSCell (e.g., cell 151) of another target candidate SN.

[0102] like Figure 4 As shown, network device 110 (i.e., MN) can transmit a configuration for a subsequent CPAC 430 to terminal device 120, which includes execution conditions for the subsequent CPC received from network device 140. The configuration for the subsequent CPAC may include a first configuration associated with a first candidate PSCell (e.g., cell 142) of the target candidate SN. The first configuration may include a set of configurations, and the configurations in the set of configurations may include MCG configurations.

[0103] In some embodiments, the MCG configuration may include execution conditions for subsequent CPCs from the first candidate PSCell (e.g., cell 142) to the second candidate PSCell. In other words, after generating an RRC reconfiguration that includes a conditional reconfiguration for the first candidate PSCell (e.g., cell 142), the MN may include the execution conditions for subsequent CPCs from the first candidate PSCell (e.g., cell 142) in the MCG configuration of the RRC reconfiguration within the conditional reconfiguration. The MN may then transmit the RRC reconfiguration to the terminal device 120.

[0104] In other words, in the MCG configuration, the execution conditions for subsequent CPCs are set to the execution conditions associated with conditional reconfiguration for candidate PSCells (e.g., cell 141, cell 151, etc.).

[0105] For illustration, the example process can be described as follows. MN sends to UE RRCReconfiguration The message includes the CPAC configuration, i.e. RRCReconfiguration A list of messages and associated execution conditions, where each RRCReconfiguration The message contains information received from the candidate SN. RRCReconfiguration The message contains SCG and MCG configurations. The MCG configuration can include execution conditions for subsequent CPCs. Furthermore, RRCReconfiguration The message may also include the updated MCG configuration and the NR generated by the source SN. RRCReconfiguration Messages, for example, to configure the required conditional measurements.

[0106] In some embodiments, the MCG configuration may further include an indication of one or more configurations associated with one or more second candidate PSCells from a set of paused or deactivated configurations. In other words, the MN may also include an indication of conditional reconfiguration of pause, deactivation, or invalidation in the MCG configuration.

[0107] In some embodiments, if the target candidate SN (e.g., network device 140) does not provide execution conditions for subsequent CPCs from the first candidate PSCell (e.g., cell 142) to the second candidate PSCell (i.e., cell 152), or if the target candidate SN indicates in its SN Add Request Confirmation message that it does not support subsequent CPCs from the first candidate PSCell (e.g., cell 142) to the second candidate PSCell (e.g., cell 152), the MN may include an indication of suspension, deactivation, or invalidation of conditional reconfiguration associated with the second candidate PSCell (i.e., cell 152) in the MCG configuration. In some embodiments, this indication may be included in the conditional reconfiguration associated with the second candidate PSCell (i.e., cell 152).

[0108] refer to Figure 4 Upon receiving an instruction, or upon determining that no execution conditions for subsequent CPACs from the first candidate PSCell to one or more second candidate PSCells have been received, terminal device 120 may suspend or deactivate one or more configurations in the set of 440 configurations. In some embodiments, terminal device 120 may suspend or deactivate conditional reconfiguration evaluation for an associated conditional reconfiguration. Alternatively or additionally, terminal device 120 may treat conditional reconfiguration as suspended, deactivated, or invalid.

[0109] In some embodiments, the first configuration may include execution conditions received from network device 140 (i.e., the target candidate SN) for subsequent CPCs from the first candidate PSCell (e.g., cell 142) to the second candidate PSCell. In other words, after generating an RRC reconfiguration that includes a conditional reconfiguration for the first candidate PSCell (e.g., cell 142) of the target candidate SN (e.g., network device 140), the MN may include the execution conditions for subsequent CPCs from the first candidate PSCell (i.e., cell 142) in the conditional configuration for the first candidate PSCell (i.e., cell 142). The MN may then transmit the RRC reconfiguration to terminal device 120. Terminal device 120 receives the execution conditions for subsequent CPCs and stores them in UE variables.

[0110] For illustration, the example process can be described as follows. MN sends to UE RRCReconfiguration The message includes the CPAC configuration (i.e., RRCReconfiguration A list of messages and associated execution conditions), and execution conditions for subsequent CPCs, each of which RRCReconfiguration The message contains information received from the candidate SN. RRCReconfiguration The message contains SCG and MCG configurations. Additionally... RRCReconfiguration The message may also include the updated MCG configuration and the NR generated by the source SN. RRCReconfiguration Messages, for example, to configure the required conditional measurements.

[0111] Continue to refer to Figure 4 If a PSCell change or addition is to be executed for the first candidate PSCell (e.g., cell 142), the terminal device 120 can update the execution conditions stored for the set of second candidate PSCells using the execution conditions for subsequent CPCs from the first candidate PSCell to the second candidate PSCell. In other words, after a PSCell change or addition is made to the first candidate PSCell, the terminal device 120 can update or set the conditional reconfiguration execution conditions associated with other candidate PSCells to the execution conditions for subsequent CPCs.

[0112] In some embodiments, PSCell change or addition can be conditional. In some embodiments, PSCell change or addition can be unconditional. In other words, after a random access procedure triggered by successful completion of a synchronous reconfiguration in the SpCell configuration for the SCG, the target PSCell is a candidate PSCell (e.g., cell 142). For example, terminal device 120 can replace the execution condition of a conditional reconfiguration associated with another candidate PSCell (e.g., cell 151) in the UE variables with the execution condition for a subsequent CPC from candidate PSCell (e.g., cell 142) to another candidate PSCell (e.g., cell 151).

[0113] In some embodiments, the first configuration may include an indication of one or more configurations associated with one or more second candidate PSCells from a set of pause or deactivation configurations.

[0114] refer to Figure 4 Upon receiving an instruction, or upon determining that no execution conditions for subsequent CPACs from the first candidate PSCell to one or more second candidate PSCells have been received, terminal device 120 may suspend or deactivate one or more configurations in the set of configurations 451. In some embodiments, terminal device 120 may suspend or deactivate conditional reconfiguration evaluation for an associated conditional reconfiguration. Alternatively or additionally, terminal device 120 may treat conditional reconfiguration as suspended, deactivated, or invalid.

[0115] For example, if, after a PSCell change or addition to the first candidate PSCell (e.g., cell 142), no execution condition is received to trigger a subsequent CPC from a conditional reconfiguration or the first candidate PSCell (e.g., cell 142) to another conditional reconfiguration or the second candidate PSCell (e.g., cell 152), or an explicit indication of suspension, deactivation, or invalidation of another conditional reconfiguration or the second candidate PSCell is received, then the terminal device 120 may consider the other conditional reconfiguration or the second candidate PSCell (e.g., cell 152) to be invalidated, suspended, or deactivated. Alternatively, the terminal device 120 may suspend or deactivate the conditional reconfiguration evaluation for the other conditional reconfiguration or the second candidate PSCell (e.g., cell 152).

[0116] Based on the execution conditions for subsequent CPAC, terminal device 120 can perform a conditional reconfiguration assessment.

[0117] Using process 400, it is possible to support the generation of execution conditions for subsequent CPCs from candidate SNs.

[0118] It should be understood that Figures 2 to 4 The steps and their order are for illustrative purposes only and are not intended to be limiting. More or fewer steps are also possible. Example implementation of the method

[0119] Therefore, embodiments of this disclosure provide methods for communication implemented at a terminal device and an MN. These methods will be referenced below. Figures 5 to 8 Described.

[0120] Figure 5 The illustration depicts an example method 500 of communication implemented at a terminal device according to some embodiments of the present disclosure. For example, method 500 can be implemented as follows: Figure 1 The method is executed at the terminal device 120 shown. It should be understood that method 500 may include additional boxes not shown and / or some boxes shown may be omitted, and the scope of this disclosure is not limited in this respect.

[0121] like Figure 5 As shown in the diagram, at box 510, terminal device 120 determines that a subsequent CPAC is executed.

[0122] At block 520, terminal device 120 determines that the bearer type for the DRB has been changed for subsequent CPAC. In some embodiments, terminal device 120 may determine that the bearer type for the DRB has been changed if the key to be used for the DRB has been changed. If the key to be used for the DRB has not been changed, terminal device 120 may determine that the bearer type for the DRB has not been changed.

[0123] At block 530, terminal device 120 performs a first operation. In some embodiments, the first operation may include reconstructing the PDCP entity of the DRB. In some embodiments, the first operation may include: if the PDCP entity of the DRB is not configured with encryption disabled, configuring an encryption algorithm and key for the PDCP entity, the encryption algorithm and key being used for encrypting data associated with a master key or a secondary key. In some embodiments, the first operation may include: if the PDCP entity of the DRB is configured with integrity protection, configuring an integrity protection algorithm and key for the PDCP entity, the integrity protection algorithm and key being used for integrity protection of data associated with a master key or a secondary key. In some embodiments, the first operation may include reconstructing at least one RLC entity for at least one RLC bearer associated with the DRB. It should be understood that the first operation may include any combination of the above operations.

[0124] In some embodiments, if the bearer type for the DRB is not changed for subsequent CPACs, the terminal device 120 may perform a second operation. In some embodiments, the second operation may include triggering the PDCP entity of the DRB to perform data recovery. In some embodiments, the second operation may include rebuilding at least one RLC entity for at least one SCG RLC bearer associated with the DRB. It should be understood that the second operation may include any combination of the above operations.

[0125] In this way, during subsequent CPAC, the terminal device can perform L2 processing even if the bearer type changes without explicit instructions from the network. Therefore, lossless support for AM DRB is possible.

[0126] Figure 6 The illustration shows another example method 600 of communication implemented at a terminal device according to some embodiments of the present disclosure. For example, method 600 can be implemented as follows: Figure 1 The method is executed at the terminal device 120 shown. It should be understood that method 600 may include additional boxes not shown and / or some boxes shown may be omitted, and the scope of this disclosure is not limited in this respect.

[0127] like Figure 6 As shown in the diagram, at box 610, terminal device 120 determines that subsequent CPCs will be executed from the first cell to the second cell.

[0128] At frame 620, terminal device 120 determines that the first cell is not a candidate PSCell for subsequent CPCs.

[0129] At box 630, terminal device 120 performs an operation. In some embodiments, this operation may include determining that the subsequent CPC is an inter-SN subsequent CPC. In some embodiments, this operation may include determining that the subsequent CPC is an intra-SN subsequent CPC.

[0130] In some embodiments, the operation may include: determining whether a subsequent CPC is an inter-SN subsequent CPC or an intra-SN subsequent CPC by determining a first identifier value as the identifier value of the serving cell and comparing the first identifier value with a second identifier value for the second cell.

[0131] In some embodiments, terminal device 120 may determine the first identifier value based on the configuration of a first identifier value from an MN (e.g., network device 110) or an SN (e.g., a target candidate SN). In some embodiments, terminal device 120 may determine the first identifier value as a default value.

[0132] In some embodiments, if the first identifier value is the same as the second identifier value, the terminal device 120 can determine that the subsequent CPC is an intra-SN subsequent CPC. In some embodiments, if the first identifier value is different from the second identifier value, the terminal device 120 can determine that the subsequent CPC is an inter-SN subsequent CPC. In some embodiments, if the subsequent CPC is an inter-SN subsequent CPC, the terminal device 120 can replace the identifier value of the serving cell with the second identifier value.

[0133] In some embodiments, the terminal device 120 may determine that a subsequent CPC is an inter-SN subsequent CPC based on at least one of the following: the first cell is not configured with a first identifier value, or the second cell is not configured with a second identifier value. In some embodiments, the terminal device 120 may determine that a subsequent CPC is an intra-SN subsequent CPC based on at least one of the following: the first cell is not configured with a first identifier value, or the second cell is not configured with a second identifier value.

[0134] In some embodiments, if the subsequent CPC is an inter-SN subsequent CPC, the terminal device 120 can derive the secondary key by using a security key counter in a list of security key counters associated with the second identifier value, and discard the security key counter from the list of security key counters.

[0135] In some embodiments, if the subsequent CPC is an inter-SN subsequent CPC, the terminal device 120 may perform an operation on the DRB that is the SN-terminated DRB, the operation including at least one of the following: reconstructing the PDCP entity of the DRB; if the PDCP entity of the DRB is not configured with encryption de-enabled, configuring an encryption algorithm and key for the PDCP entity, the encryption algorithm and key being used for encrypting data associated with a secondary key; if the PDCP entity of the DRB is configured with integrity protection, configuring an integrity protection algorithm and key for the PDCP entity, the integrity protection algorithm and key being used for integrity protection of data associated with a secondary key; or reconstructing at least one RLC entity for at least one RLC bearer associated with the DRB.

[0136] In some embodiments, if the subsequent CPC is an inter-SN subsequent CPC, the terminal device 120 may perform an operation for at least one SRB between the SN corresponding to the second cell and the terminal device, the operation including at least one of the following: reconstructing a PDCP entity for at least one SRB; configuring the PDCP entity to apply an encryption algorithm and key for encryption of Radio Resource Control (RRC) signaling associated with a secondary key; configuring the PDCP entity to apply an integrity protection algorithm and key for integrity protection of RRC signaling associated with a secondary key; or reconstructing at least one RLC entity for at least one RLC bearer associated with at least one SRB.

[0137] In some embodiments, if the subsequent CPC is an inter-SN subsequent CPC, the terminal device 120 may perform an operation including at least one of the following: reconstructing at least one RLC entity for at least one SCG radio link control (RLC) bearer associated with a DRB that is a DRB terminating the MN; reconstructing at least one RLC entity for at least one SCG RLC bearer associated with an SRB between the MN and the terminal device; or reconstructing RLC entities for all SCG RLC bearers.

[0138] In some embodiments, if the subsequent CPC is a subsequent CPC within the SN, the terminal device 120 may perform an operation on the DRB that is the SN-terminated DRB, the operation including at least one of the following: triggering the PDCP entity of the DRB to perform data recovery; or reconstructing at least one RLC entity for at least one SCG RLC bearer associated with the DRB.

[0139] In some embodiments, if the subsequent CPC is a subsequent CPC within the SN, the terminal device 120 may perform an operation on the SRB between the SN and the terminal device, the operation including at least one of the following: the PDCP entity that triggered the SRB performs SDU discard; or at least one RLC entity is rebuilt for at least one SCG RLC bearer associated with the SRB.

[0140] In some embodiments, if the subsequent CPC is a subsequent CPC within the SN, the terminal device 120 may perform an operation including at least one of the following: reconstructing at least one RLC entity for at least one SCG RLC bearer associated with at least one SRB between the MN and the terminal device; reconstructing at least one RLC entity for at least one SCG RLC bearer associated with at least one SCG RLC bearer that is a DRB terminating the MN; or reconstructing RLC entities for all SCG RLC bearers.

[0141] In this way, during subsequent CPACs, the terminal device can identify subsequent CPCs within the same SN and subsequent CPCs between SNs. This can facilitate different behaviors in security key updates and L2 processing for the cases of subsequent CPCs within the same SN and subsequent CPCs between SNs.

[0142] Figure 7 The illustration depicts yet another example method 700 of communication implemented at a terminal device according to some embodiments of the present disclosure. For example, method 700 can be implemented as follows: Figure 1 The method is executed at the terminal device 120 shown. It should be understood that method 700 may include additional boxes not shown and / or some boxes shown may be omitted, and the scope of this disclosure is not limited in this respect.

[0143] like Figure 7 As shown, at block 710, terminal device 120 receives from MN a first configuration of a subsequent CPAC associated with a first candidate PSCell of a candidate SN. The first configuration includes a set of configurations, including MCG configurations.

[0144] In some embodiments, the MCG configuration may include execution conditions for subsequent CPCs from the first candidate PSCell to the set of second candidate PSCells. In some embodiments, the MCG configuration may also include an indication to suspend or deactivate one or more configurations in the set of configurations associated with one or more second candidate PSCells. In some embodiments, if an indication is received or no execution conditions for subsequent CPCs from the first candidate PSCell to one or more second candidate PSCells are received, the terminal device 120 may suspend or deactivate one or more configurations in the set of configurations.

[0145] In some embodiments, the first configuration may include execution conditions for subsequent CPCs from the first candidate PSCell to the second candidate PSCell. In some embodiments, if a PSCell change or addition for the first candidate PSCell is to be executed, the terminal device 120 may update the stored execution conditions for the second candidate PSCell set using the execution conditions for subsequent CPCs from the first candidate PSCell to the second candidate PSCell set.

[0146] In some embodiments, the first configuration may further include an indication to suspend or deactivate one or more configurations associated with one or more second candidate PSCells in a set of configurations. In some embodiments, if the indication is received or no execution condition for subsequent CPACs from the first candidate PSCell to one or more second candidate PSCells is received, the terminal device 120 may suspend or deactivate one or more configurations in the set of configurations.

[0147] In this way, it is possible to support the generation of execution conditions for subsequent CPCs by the SN.

[0148] Figure 8 An example method 800 of communication implemented at MN according to some embodiments of the present disclosure is illustrated. For example, method 800 can be implemented as follows: Figure 1 The method is performed at network device 110 shown. It should be understood that method 800 may include additional boxes not shown and / or some boxes shown may be omitted, and the scope of this disclosure is not limited in this respect.

[0149] like Figure 8 As shown, at block 810, network device 110, acting as the MN, transmits to terminal device 120 the first configuration of the subsequent CPAC associated with the first candidate PSCell of the candidate SN. The first configuration includes a set of configurations, and the configurations in the set of configurations include the MCG configuration.

[0150] In some embodiments, the MCG configuration may include execution conditions for subsequent CPCs from the set of first candidate PSCells to the set of second candidate PSCells. In some embodiments, the MCG configuration may also include indications for one or more configurations associated with one or more second candidate PSCells in the set of paused or deactivated configurations.

[0151] In some embodiments, the first configuration may include execution conditions for subsequent CPCs from the set of first candidate PSCells to the set of second candidate PSCells. In some embodiments, the first configuration may also include an indication of one or more configurations associated with one or more second candidate PSCells in the set of pause or deactivation configurations.

[0152] In this way, it is possible to support the generation of execution conditions for subsequent CPCs from candidate SNs.

[0153] It should be understood that the operation and reference of methods 500, 600, 700 and 800 are... Figures 2 to 4 The operations described correspond to this, and therefore, for the sake of brevity, other details will not be repeated here. Example implementation of the device

[0154] Figure 9 This is a simplified block diagram of a device 900 suitable for implementing embodiments of the present disclosure. The device 900 can be considered as follows: Figure 1 Another example implementation of the terminal device 120 or network device 110 shown. Therefore, device 900 may be implemented at or as a part of the terminal device 120 or network device 110.

[0155] As shown, device 900 includes a processor 910, a memory 920 coupled to the processor 910, a suitable transceiver 940 coupled to the processor 910, and a communication interface coupled to the transceiver 940. The memory 910 stores at least a portion of a program 930. The transceiver 940 can be used for required bidirectional or unidirectional communication. The transceiver 940 may include at least one of a transmitter 942 or a receiver 944. The transmitter 942 and receiver 944 may be functional modules or physical entities. The transceiver 940 has at least one antenna to facilitate communication, although in practice, the access nodes mentioned in this application may have multiple antennas. The communication interface can represent any interface required for communication with other network elements, such as the X2 / Xn interface for bidirectional communication between eNB / gNB, the S1 / NG interface for communication between the Mobility Management Entity (MME) / Access and Mobility Management Function (AMF) / SGW / UPF and eNB / gNB, the Un interface for communication between eNB / gNB and Relay Node (RN), or the Uu interface for communication between eNB / gNB and terminal equipment.

[0156] Program 930 is assumed to include program instructions that, when executed by the associated processor 910, enable device 900 to operate according to embodiments of this disclosure, as referenced herein. Figures 1 to 8 The embodiments discussed herein can be implemented by computer software executable by the processor 910 of device 900, or by hardware, or by a combination of software and hardware. Processor 910 can be configured to implement various embodiments of this disclosure. Furthermore, a combination of processor 910 and memory 920 can form a processing unit 950 suitable for implementing various embodiments of this disclosure.

[0157] Memory 920 can be of any type suitable for a local technology network and can be implemented using any suitable data storage technology, such as, as non-limiting examples, non-transient computer-readable storage media, semiconductor-based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory, and removable memory. Although only one memory 920 is shown in device 900, several physically different memory modules may be present in device 900. Processor 910 can be of any type suitable for a local technology network and, as non-limiting examples, may include one or more of the following: general-purpose computer, special-purpose computer, microprocessor, digital signal processor (DSP), and processor based on a multi-core processor architecture. Device 900 may have multiple processors, such as application-specific integrated circuit chips that are time-dependent on a clock synchronized with the main processor.

[0158] In some embodiments, a terminal device includes a circuit system configured to: determine that a subsequent CPAC is performed; and, based on the determination that the subsequent CPAC has been changed for the bearer type of the DRB, perform a first operation, the first operation including at least one of the following: reconstructing the PDCP entity of the DRB; configuring an encryption algorithm and key for the PDCP entity based on the determination that the PDCP entity of the DRB is not configured with encryption disabled, the encryption algorithm and key being used for encrypting data associated with a master key or a secondary key; configuring an integrity protection algorithm and key for the PDCP entity based on the determination that the PDCP entity of the DRB is configured with integrity protection, the integrity protection algorithm and key being used for integrity protection of data associated with a master key or a secondary key; or reconstructing at least one RLC entity for at least one RLC bearer associated with the DRB.

[0159] In some embodiments, a terminal device includes a circuit system configured to: determine that a subsequent CPC is to be executed from a first cell to a second cell; and, based on the determination that the first cell is not a candidate PSCell for the subsequent CPC, perform an operation including one of the following: determining that the subsequent CPC is an inter-SN subsequent CPC or an intra-SN subsequent CPC by determining a first identifier value as the identifier value of the serving cell and comparing the first identifier value with a second identifier value for the second cell; determining that the subsequent CPC is an inter-SN subsequent CPC; and determining that the subsequent CPC is an intra-SN subsequent CPC.

[0160] In some embodiments, a terminal device includes a circuit system configured to: receive from an MN a first configuration of a subsequent CPC associated with a first candidate PSCell of a candidate SN, the first configuration including a set of configurations, the configurations in the set including an MCG configuration, wherein the MCG configuration includes execution conditions for subsequent CPCs for a set of subsequent CPCs from the first candidate PSCell to the second candidate PSCell, or wherein the first configuration further includes execution conditions for subsequent CPCs for a set of subsequent CPCs from the first candidate PSCell to the second candidate PSCell.

[0161] In some embodiments, an MN includes a circuit system configured to transmit to a terminal device a first configuration of a subsequent CPC associated with a first candidate PSCell of a candidate SN, the first configuration including a set of configurations, the configurations in the set including an MCG configuration, wherein the MCG configuration includes execution conditions for subsequent CPCs for a set of subsequent CPCs from the first candidate PSCell to the second candidate PSCell, or wherein the first configuration further includes execution conditions for subsequent CPCs for a set of subsequent CPCs from the first candidate PSCell to the second candidate PSCell.

[0162] As used herein, the term "circuit system" can refer to hardware circuitry and / or a combination of hardware circuitry and software. For example, a circuit system can be a combination of analog and / or digital hardware circuitry with software / firmware. As another example, a circuit system can be any part of a hardware processor with software, including (multiple) digital signal processors, software, and (multiple) memories, which work together to enable a device, such as a terminal device or network device, to perform various functions. In yet another example, a circuit system can be hardware circuitry and / or a processor, such as a microprocessor or a portion thereof, which requires software / firmware for operation, but the software may be absent when operation is not required. As used herein, the term circuit system also encompasses an implementation of hardware circuitry or (multiple) processors or a portion thereof, along with its accompanying software and / or firmware.

[0163] Generally, the various embodiments of this disclosure can be implemented in hardware or dedicated circuitry, software, logic, or any combination thereof. Some aspects can be implemented in hardware, while others can be implemented in firmware or software that can be executed by a controller, microprocessor, or other computing device. Although various aspects of the embodiments of this disclosure are illustrated and described as block diagrams, flowcharts, or using some other graphical representation, it will be understood that, as non-limiting examples, the blocks, apparatuses, systems, techniques, or methods described herein can be implemented in hardware, software, firmware, dedicated circuitry or logic, general-purpose hardware or controllers or other computing devices, or some combination thereof.

[0164] This disclosure also provides at least one computer program product tangibly stored on a non-transitory computer-readable storage medium. The computer program product includes computer-executable instructions, such as those included in program modules, executed in a device on a target real or virtual processor, to perform the above-referenced instructions. Figures 1 to 8 The process or method described herein. Typically, a program module includes routines, programs, libraries, objects, classes, components, data structures, etc., that perform specific tasks or implement specific abstract data types. The functionality of a program module can be combined or split among program modules as needed in various embodiments. The machine-executable instructions used in a program module can be executed locally or on a distributed device. In a distributed device, a program module can reside on both local and remote storage media.

[0165] Program code used to perform the methods of this disclosure may be written in any combination of one or more programming languages. This program code may be provided to a processor or controller of a general-purpose computer, special-purpose computer, or other programmable data processing apparatus, such that when executed by the processor or controller, the program code causes the functions / operations specified in the flowcharts and / or block diagrams to be implemented. The program code may be executed entirely on a machine, partially on a machine, as a stand-alone software package, partially on a machine and partially on a remote machine, or entirely on a remote machine or server.

[0166] The aforementioned program code can be embodied on a machine-readable medium, which can be any tangible medium capable of containing or storing a program for use by or in connection with an instruction execution system, apparatus, or device. The machine-readable medium can be a machine-readable signal medium or a machine-readable storage medium. Machine-readable media can include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatuses, or devices, or any suitable combination thereof. More specific examples of machine-readable storage media will include electrical connections having one or more wires, portable computer floppy disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fibers, portable optical disc read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof.

[0167] Furthermore, although operations are described in a specific order, this should not be construed as requiring the operations to be performed in the specific order or sequential sequence shown, or to perform all of the shown operations, to achieve the desired result. In some cases, multitasking and parallel processing may be advantageous. Similarly, while several specific implementation details are included in the foregoing discussion, these should not be construed as limiting the scope of this disclosure, but rather as descriptions of features that may be specific to particular embodiments. Certain features described in the context of a single embodiment may also be implemented in combination in a single embodiment. Conversely, various features described in the context of a single embodiment may also be implemented individually or in any suitable sub-combination in multiple embodiments.

[0168] Although this disclosure has been described in language specific to structural features and / or methodological actions, it should be understood that the disclosure as defined in the appended claims is not necessarily limited to the specific features or actions described above. Rather, the specific features and actions described above are disclosed as examples of implementing the claims.

Claims

1. A terminal device, comprising: The processor is configured to cause the terminal device to: It is confirmed that subsequent conditional primary and secondary cell additions or changes (CPAC) will be implemented; as well as Based on the determination of the subsequent CPAC change according to the bearer type for the Data Radio Bearer (DRB), a first operation is performed, the first operation including at least one of the following: Reconstruct the Packet Data Convergence Protocol (PDCP) entity of the DRB; Based on the determination that the PDCP entity of the DRB is not configured with encryption disabled, an encryption algorithm and a key are configured for the PDCP entity, the encryption algorithm and the key being used to encrypt data associated with a master key or a secondary key; Based on the determination that the PDCP entity of the DRB is configured with integrity protection, an integrity protection algorithm and a key are configured for the PDCP entity, the integrity protection algorithm and the key being used for integrity protection of data associated with a master key or a secondary key; or Reconstruct at least one RLC entity for at least one Radio Link Control (RLC) bearer associated with the DRB.

2. The terminal device according to claim 1, wherein the terminal device is further configured to: Based on the determination that the bearer type for the DRB has not been changed for the subsequent CPAC, a second operation is performed, the second operation including at least one of the following: The PDCP entity that triggers the DRB to perform data recovery; or Reconstruct at least one RLC entity for at least one secondary cell group (SCG) RLC bearer associated with the DRB.

3. The terminal device according to claim 1, wherein the terminal device is further configured to: Based on the determination that the key to be used for the DRB has been changed, it is determined that the bearer type for the DRB has been changed; or Based on the determination that the key to be used in the DRB has not been changed, it is determined that the bearer type for the DRB has not been changed.

4. A terminal device, comprising: The processor is configured to cause the terminal device to: It is determined that subsequent conditional primary / secondary cell (PSCell) changes (CPCs) will be executed from cell one to cell two; and Based on the determination that the first cell is not a candidate PSCell for the subsequent CPC, an operation is performed, the operation including one of the following: By determining the first identifier value as the identifier value of the serving cell and comparing the first identifier value with the second identifier value for the second cell, it is determined whether the subsequent CPC is an inter-subordinate node (SN) subsequent CPC or an intra-SN subsequent CPC; Determine that the subsequent CPC is a subsequent CPC between the SNs; and The subsequent CPC is determined to be a subsequent CPC within the SN.

5. The terminal device of claim 4, wherein the terminal device is configured to determine the first identifier value by: The first identifier value is determined based on the configuration of the first identifier value from the master node or the slave node; or The first identifier value is set as the default value.

6. The terminal device of claim 4, wherein the terminal device is configured to determine whether the subsequent CPC is an inter-SN subsequent CPC or an intra-SN subsequent CPC by: Based on the determination that the first identifier value and the second identifier value are the same, it is determined that the subsequent CPC is a subsequent CPC within the SN; or Based on the determination that the first identifier value and the second identifier value are different, it is determined that the subsequent CPC is the subsequent CPC between the SNs.

7. The terminal device according to claim 6, wherein the terminal device is further configured to: Based on the determination that the subsequent CPC is the subsequent CPC between the SNs, the identifier value of the serving cell is replaced with the second identifier value.

8. The terminal device according to claim 4, wherein the terminal device is further configured to: The subsequent CPC is determined to be the inter-SN subsequent CPC based on at least one of the following: The first cell is not configured with the first identifier value, or The second cell was not configured with the second identifier value; or The subsequent CPC is determined to be a subsequent CPC within the SN based on at least one of the following: The first cell is not configured with the first identifier value, or The second cell was not configured with the second identifier value.

9. The terminal device according to claim 4, wherein the terminal device is further configured to: Based on the determination of the subsequent CPC between the SNs, The secondary key is derived by using the security key counters in the list of security key counters associated with the second identifier value; and Discard the security key counter from the list of security key counters.

10. The terminal device according to claim 4, wherein the terminal device is further configured to: Based on the determination that the subsequent CPC is the inter-SN subsequent CPC, an operation is performed on the DRB as the SN termination data radio bearer (DRB), the operation including at least one of the following: Reconstruct the Packet Data Convergence Protocol (PDCP) entity of the DRB; Based on the determination that the PDCP entity of the DRB is not configured with encryption disabled, an encryption algorithm and a key are configured for the PDCP entity, the encryption algorithm and the key being used to encrypt data associated with the secondary key; Based on the determination that the PDCP entity of the DRB is configured with integrity protection, an integrity protection algorithm and a key are configured for the PDCP entity, the integrity protection algorithm and the key being used for integrity protection of data associated with the secondary key; or Reconstruct at least one RLC entity for at least one Radio Link Control (RLC) bearer associated with the DRB.

11. The terminal device according to claim 4, wherein the terminal device is further configured to: Based on the determination that the subsequent CPC is the inter-SN subsequent CPC, an operation is performed for at least one signaling radio bearer (SRB) between the SN corresponding to the second cell and the terminal device, the operation including at least one of the following: For at least one SRB, rebuild the Packet Data Convergence Protocol (PDCP) entity; The PDCP entity is configured to apply an encryption algorithm and a key, which are used for encryption of Radio Resource Control (RRC) signaling associated with a secondary key; Configure the PDCP entity to apply an integrity protection algorithm and key, the integrity protection algorithm and key being used for integrity protection of the RRC signaling associated with the secondary key; or Reconstruct at least one RLC entity for at least one Radio Link Control (RLC) bearer associated with at least one SRB.

12. The terminal device according to claim 4, wherein the terminal device is further configured to: Based on the determination that the subsequent CPC is the subsequent CPC between the SNs, an operation is performed, the operation including at least one of the following: Reconstruct at least one RLC entity for at least one secondary cell group (SCG) radio link control (RLC) bearer associated with the DRB that is the primary node (MN) terminating data radio bearer (DRB); Reconstruct at least one RLC entity for at least one SCG RLC bearer associated with the signaling radio bearer (SRB) between the MN and the terminal device; or Reconstruct the RLC entity for all SCG RLC bearers.

13. The terminal device according to claim 4, wherein the terminal device is further configured to: Based on the determination that the subsequent CPC is a subsequent CPC within the SN, an operation is performed on the DRB that serves as the SN termination data radio bearer (DRB), the operation including at least one of the following: The Packet Data Convergence Protocol (PDCP) entity of the DRB is triggered to perform data recovery; or Reconstruct at least one RLC entity for at least one secondary cell group (SCG) radio link control (RLC) bearer associated with the DRB.

14. The terminal device according to claim 4, wherein the terminal device is further configured to: Based on the determination that the subsequent CPC is a subsequent CPC within the SN, an operation is performed on the signaling radio bearer (SRB) between the SN and the terminal device, the operation including at least one of the following: The Packet Data Convergence Protocol (PDCP) entity that triggers the SRB to discard Service Data Units (SDUs); or Reconstruct at least one RLC entity for at least one secondary cell group (SCG) radio link control (RLC) bearer associated with the SRB.

15. The terminal device according to claim 4, wherein the terminal device is further configured to: Based on the determination that the subsequent CPC is a subsequent CPC within the SN, an operation is performed, the operation including at least one of the following: Reconstruct at least one RLC entity for at least one secondary cell group (SCG) radio link control (RLC) bearer associated with at least one signaling radio bearer (SRB) between the master node (MN) and the terminal device; Reconstruct at least one RLC entity for at least one SCG RLC bearer associated with the DRB as the MN termination data radio bearer; or Reconstruct the RLC entity for all SCG RLC bearers.

16. A terminal device, comprising: The processor is configured to cause the terminal device to: The primary node receives a first configuration of subsequent conditional PSCell Addition or Change (CPAC) associated with the first candidate primary / secondary cell (PSCell) of the candidate secondary node (SN), the first configuration comprising a set of configurations, the set of configurations including primary cell group (MCG) configurations. The MCG configuration includes the execution conditions for subsequent conditional PSCell changes (CPCs) for the set from the first candidate PSCell to the second candidate PSCell, or The first configuration also includes the execution conditions for the subsequent CPCs for the set from the first candidate PSCell to the second candidate PSCell.

17. The terminal device according to claim 16, wherein the terminal device is further configured to: Based on the determination of whether a PSCell change or addition to the first candidate PSCell is to be executed, the execution conditions stored for the set of the second candidate PSCell are updated using the execution conditions for the subsequent CPCs from the first candidate PSCell to the set of the second candidate PSCell.

18. The terminal device according to claim 16, wherein the MCG configuration or the first configuration further comprises: An indication to suspend or deactivate one or more configurations associated with one or more second candidate PSCells in the set of configurations.

19. The terminal device according to claim 18, wherein the terminal device is further configured to: Based on the determination that the instruction has been received or that no execution condition for the subsequent CPAC from the first candidate PSCell to the one or more second candidate PSCells has been received, the one or more configurations in the set of configurations are suspended or deactivated.

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