UE and Method

Abstract

Embodiments of this disclosure relate to communication devices and methods. In one embodiment, upon determining that a subsequent CPAC is to be performed, the terminal device determines whether the bearer type of the DRB is changed for the subsequent CPAC. If the bearer type is changed, the terminal device performs L2 handling. In this way, during a subsequent CPAC, the terminal device can perform L2 handling in the event of a bearer type change without explicit instruction from the network. Thus, lossless operation can be supported for AM DRB.

Description

[[Technical Field]]

[0001] Embodiments of the present disclosure generally relate to the field of telecommunications, and in particular, to a communication apparatus and method for conditional cell change. [[Background Art]]

[0002] For conditional primary secondary cell (PSCell) addition or change (CPAC) in third generation partnership project (3GPP®) Release 17, a terminal device configured with CPAC must release the CPAC configuration after completing random access to the target PSCell. Therefore, the terminal device has no opportunity to perform a subsequent CPAC without prior CPAC reconfiguration and re-initialization from the network side. This increases cell change delay and signaling overhead, especially for frequent secondary cell group (SCG) changes when operating in frequency range 2 (FR2). Accordingly, multi-random access technology dual connectivity (MR-DC) with selective activation of cell groups aims to enable subsequent CPAC after SCG change without reconfiguration and re-initialization of CPAC preparation from the network side. This results in reduced signaling overhead and interruption time for SCG change. However, the solution for subsequent CPAC is still incomplete and needs further development. [[Summary of the Invention]]

[0003] In general, embodiments of the present disclosure provide a communication method, a device, and a computer storage medium for subsequent conditional cell change.

[0004] In the first embodiment, a terminal device is provided. The terminal device comprises a processor, the processor is configured to perform a first operation which includes at least one of the following: determining that a subsequent CPAC is to be performed and determining that the bearer type of the data radio bearer (DRB) is to be changed for the subsequent CPAC; configuring the PDCP entity using an encryption algorithm and a key for encrypting data associated with a master key or secondary key, according to the determination that the PDCP entity of the DRB is not configured with encryption disabled; configuring the PDCP entity using an integrity protection algorithm and a key for protecting the integrity of data associated with a master key or secondary key, according to the determination that the PDCP entity of the DRB is configured with integrity protection; or re-establishing at least one RLC entity for at least one radio link control (RLC) bearer associated with the DRB.

[0005] In a second embodiment, a terminal device is provided. The terminal device comprises a processor, the processor is configured to perform an operation which includes determining that a subsequent conditional PSCell change (CPC) is performed from a first cell to a second cell; determining a first identification value as the identification value of the serving cell according to the determination that the first cell is not a candidate PSCell for the subsequent CPC; and determining that the subsequent CPC is an intersecondary node (SN) subsequent CPC or an intra-SN subsequent CPC by comparing the first identification value with the second identification value of the second cell; determining that the subsequent CPC is an inter-SN subsequent CPC; or determining that the subsequent CPC is an intra-SN subsequent CPC.

[0006] In a third embodiment, a terminal device is provided. The terminal device comprises a processor, the processor configured to cause the terminal device to receive from a master node (MN) a first configuration of a subsequent CPAC associated with a first candidate PSCell of a candidate SN, the first configuration comprising a set of configurations, the configurations within the set of configurations comprising a master cell group (MCG) configuration, the MCG configuration comprising execution conditions for a subsequent CPC from a first candidate PSCell to a second candidate PSCell set, or the first configuration further comprising execution conditions for a subsequent CPC from a first candidate PSCell to a second candidate PSCell set.

[0007] In a fourth aspect, a master node is provided. The master node comprises a processor, the processor configured to cause the master node to transmit a first configuration of a subsequent CPAC associated with a first candidate PSCell of a candidate SN to a terminal device, the first configuration comprising a set of configurations, the configurations within the set of configurations comprising an MCG configuration, the MCG configuration comprising execution conditions for a subsequent CPC from a first candidate PSCell to a second candidate PSCell set, or the first configuration further comprising execution conditions for a subsequent CPC from a first candidate PSCell to a second candidate PSCell set.

[0008] In a fifth aspect, a method of communication is provided. The method includes performing a first operation in a terminal device, which includes determining that a subsequent CPAC is to be performed; re-establishing the PDCP entity of the DRB in accordance with the determination that the bearer type of the DRB is to be changed for the subsequent CPAC; configuring the PDCP entity with an encryption algorithm and a key for encryption of data associated with a master key or secondary key in accordance with the determination that the PDCP entity of the DRB is not configured with encryption disabled; configuring the PDCP entity with an integrity protection algorithm and a key for integrity protection of data associated with a master key or secondary key in accordance with the determination that the PDCP entity of the DRB is configured with integrity protection; or re-establishing at least one RLC entity for at least one RLC bearer associated with the DRB.

[0009] In the sixth aspect, a method of communication is provided. The method includes, in a terminal device, determining that a subsequent CPC is being performed from a first cell to a second cell; determining a first identification value as the identification value of the serving cell in accordance with the determination that the first cell is not a candidate PSCell for the subsequent CPC; determining that the subsequent CPC is an inter-SN subsequent CPC or an intra-SN subsequent CPC by comparing the first identification value with a second identification 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.

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

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

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

[0013] Other features of this disclosure will be readily apparent from the following description. [Brief explanation of the drawing]

[0014] The above and other purposes, features, and advantages of this disclosure will become more apparent through a more detailed description of some embodiments of this disclosure in the attached drawings.

[0015] [Figure 1] This figure shows an exemplary communication environment in which several embodiments of this disclosure may be implemented.

[0016] [Figure 2] Shows a schematic diagram illustrating an exemplary process of subsequent CPAC according to an embodiment of the present disclosure.

[0017] [Figure 3] Shows a schematic diagram illustrating an exemplary process of subsequent CPC according to an embodiment of the present disclosure.

[0018] [Figure 4] Shows a schematic diagram illustrating another exemplary process of subsequent CPAC according to an embodiment of the present disclosure.

[0019] [Figure 5] Shows an exemplary communication method implemented in a terminal device according to some embodiments of the present disclosure.

[0020] [Figure 6] Shows another exemplary communication method implemented in a terminal device according to some embodiments of the present disclosure.

[0021] [Figure 7] Shows still another exemplary communication method implemented in a terminal device according to some embodiments of the present disclosure.

[0022] [Figure 8] Shows an exemplary communication method implemented in a master node according to some embodiments of the present disclosure.

[0023] [Figure 9] Shows a simplified block diagram of a device suitable for implementing an embodiment of the present disclosure.

[0024] Throughout the drawings, the same or similar reference numerals represent the same or similar elements. DETAILED DESCRIPTION OF EMBODIMENTS

[0025] The principles of this disclosure will be explained below with reference to several embodiments. These embodiments are described for illustrative purposes only and should be understood as helping those skilled in the art to understand and implement this disclosure, without implying any limitation on the scope of this disclosure. The disclosures described herein can be implemented in various forms 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 those generally understood by those skilled in the art to which this disclosure belongs.

[0027] As used herein, the term “terminal device” refers to any device having wireless or wired communication capabilities. Examples of terminal devices include user equipment (UE), personal computers, desktops, mobile phones, cellular phones, smartphones, personal digital assistants (PDAs), portable computers, tablets, wearable devices, Internet of Things (IoT) devices, Ultra-reliable and Low Latency Communication (URLLC) devices, Internet of Everything (IoE) devices, machine type communication (MTC) devices, in-vehicle devices for V2X communication (X stands for pedestrian, vehicle, or infrastructure / network), devices for Integrated Access and Backhaul (IAB), Small Data Transmission (SDT), mobility, Multicast and Broadcast Service (MBS), positioning, dynamic / flexible duplexing in commercial networks, reduced capability (RedCap), Unmanned Aircraft System (UAS), eXtended Reality (XR) devices including different types of reality such as Augmented Reality (AR), Mixed Reality (MR), and Virtual Reality (VR), and unmanned aerials, commonly known as drones, which are aircraft without human pilots. This includes, but is not limited to, space vehicles or aerial vehicles in a Non-terrestrial network (NTN), including satellites and High Altitude Platforms (HAPs), which include image capture devices such as vehicles (UAVs), devices on high-speed trains (HSTs), or devices such as digital cameras, sensors, game devices, music storage and playback devices, or internet equipment that enables wireless or wired internet access and browsing.The “Terminal Device” may further have “Multicast / Broadcast” capabilities to support public safety and mission-critical, V2X applications, transparent IPv4 / IPv6 multicast distribution, IPTV, smart TV, wireless services, software distribution over the radio, group communications, and IoT applications. It may also incorporate one or more Subscriber Identity Modules (SIMs), known as multi-SIMs. 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 can provide or host a cell or coverage from which terminal devices can communicate. Examples of network devices include, but are not limited to, Node B (NodeB or NB), evolved Node B (eNodeB or eNB), next generation Node B (gNB), transmission reception point (TRP), remote radio unit (RRU), radio head (RH), remote radio head (RRH), low-power nodes such as IAB nodes and femtonodes, piconodes, reconfigurable intelligent surface (RIS), and network control repeaters.

[0029] Terminal or network devices may possess Artificial Intelligence (AI) or machine learning capabilities. This generally involves models trained from a large amount of collected data for a specific function, which can be used to predict certain information.

[0030] Terminal or network devices can operate over multiple frequency ranges, such as FR1 (410 MHz to 7125 MHz), FR2 (24.25 GHz to 71 GHz), frequency bands greater than 100 GHz, and Tera Hertz (THz). They can also operate over licensed / unlicensed / shared spectrum. A terminal device may have two or more connections to network devices under MR-DC application scenarios. Terminal or network devices can operate in full-duplex mode, flexible duplex mode, and cross-division duplex mode.

[0031] Network devices may have network energy saving and Self-Organizing Network (SON) / Minimization of Drive Test (MDT) functions. Terminals may also have power saving functions.

[0032] Embodiments of the present disclosure may be implemented in test equipment, such as signal generators, signal analyzers, spectrum analyzers, network analyzers, test terminal devices, test network devices, and channel emulators.

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

[0034] A singular expression includes plural expressions unless the context clearly indicates otherwise. The term “includes” and its variations should be read as an open term meaning “includes, but not limited to.” The term “based on” should be read as “based at least partially.” The terms “one embodiment” and “one embodiment” should be read as “at least one embodiment.” The term “another embodiment” should be read as “at least one other embodiment.” Terms such as “first,” “second,” etc., can refer to different or the same subject. Other explicit and implicit definitions may include:

[0035] In some examples, values, procedures, or devices are referred to as “best,” “worst,” “highest,” “minimum,” “maximum,” etc. Such descriptions are intended to show that a choice may be made from among many usable functional alternatives, and it will be understood that such a choice does not need to be superior, smaller, higher, or otherwise preferable to other choices.

[0036] In relation to this disclosure, the term “cell modification 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 groups,” “selective activation of PSCell(SAP),” “subsequent CPA / CPC,” “conditional selective cell group,” or “conditional subsequent cell modification.”

[0037] In the context of this disclosure, the term "PSCell" refers to an SCG SpCell, the term "PCell" refers to an MCG SpCell, and the term "SpCell" refers to a primary cell of either an SCG or an 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 wireless bearer” may include an MN-terminated bearer or an SN-terminated bearer. An MN-terminated bearer may refer to a wireless bearer where the PDCP is located at MN. An SN-terminated bearer may refer to a wireless bearer where the PDCP is located at SN.

[0039] Recently, it was agreed that for SN-initiated and MN-initiated SCG selective activation, the candidate SN should generate execution conditions for subsequent CPCs. However, it remains unclear how to support the generation of execution conditions for subsequent CPCs for SN-initiated SCG selective activation. Furthermore, it was agreed to support updating security key counters in interSN mobility based on a pre-configured set of security key counters. However, it remains unclear when it is necessary to change the security key counters.

[0040] With this in mind, embodiments of the present disclosure provide a communication solution for subsequent CPAC to overcome the above and other potential problems. In one embodiment, upon determining that subsequent CPAC is to be performed, the terminal device determines whether the bearer type of the DRB is changed for subsequent CPAC. If the bearer type is changed, the terminal device performs a first action which includes at least one of the following: re-establishing the PDCP entity of the DRB; configuring the PDCP entity with an encryption algorithm and a key for encryption of data associated with a master key or secondary key, in accordance with the determination that the PDCP entity of the DRB is not configured with encryption disabled; configuring the PDCP entity with an integrity protection algorithm and a key for integrity protection of data associated with a master key or secondary key, in accordance with the determination that the PDCP entity of the DRB is configured with integrity protection; or re-establishing 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) handling in the event of a bearer type change without explicit instructions from the network. Therefore, lossless mode may be supported for acknowledged mode (AM) DRB.

[0041] In another embodiment, when the terminal device determines that a subsequent CPC from the first cell to the second cell is to be performed, it 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 determines the first identifier as the identifier of the serving cell and performs an operation that includes determining whether the subsequent CPC is an inter-SN subsequent CPC or an intra-SN subsequent CPC by comparing the first identifier with the second identifier for the second cell, determining whether the subsequent CPC is an inter-SN subsequent CPC, or determining whether the subsequent CPC is an intra-SN subsequent CPC. In this way, during a subsequent CPAC, the terminal device can distinguish between intra-SN subsequent CPCs and inter-SN subsequent CPCs. This may facilitate different behavior for security key updates and L2 handling for intra-SN subsequent CPCs and inter-SN subsequent CPCs.

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

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

[0044] It should be understood that this solution may be applied to SCG changes and may also be applied to MCG changes. That is, this solution may be applied for subsequent CPCs or subsequent conditional handovers. Subsequent CPCs or subsequent conditional handovers may 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.

[0045] Examples of communication networks Figure 1 shows a schematic diagram of an exemplary communication environment 100 in which embodiments of the present disclosure may be implemented. As shown in Figure 1, 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 within the cell 111 and is serviced 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 may function as an MN (also referred to hereafter as MN110 for convenience), and network device 130 may function as an SN (also referred to hereafter as SN130 for convenience). Although only cell 111 is shown, MN110 may provide multiple cells, and these cells may 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] SN130 may communicate with terminal device 120 via a communication channel such as a wireless communication channel. Similarly, MN110 may communicate with terminal device 120 via a channel such as a wireless communication channel. SN130 may communicate with MN110 via the Xn interface.

[0049] It should be understood that the number of devices or cells in Figure 1 is given for illustrative purposes only and without implying any limitation to the present disclosure. The communication environment 100 may include any suitable number of network devices and / or terminal devices and / or cells adapted to implement the implementation of the present disclosure.

[0050] Communication in communication environment 100 may comply with any suitable standard, including but not limited to Global System for Mobile Communications (GSM), Long Term Evolution (LTE), LTE-Evolution, LTE-Advanced (LTE-A), Wideband Code Division Multiple Access (WCDMA®), Code Division Multiple Access (CDMA), GSM EDGE Radio Access Network (GERAN), and Machine Type Communication (MTC). Embodiments of this disclosure may be implemented in accordance with any generation of communication protocol that is currently known or will 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 Network, or sixth generation (6G) Network.

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

[0052] Terminal device 120 is configured with candidate cells 131-133, 141-143, and 151-153. In some scenarios, terminal device 120 may initially communicate only with network device 110. As terminal device 120 moves, if the conditions of a candidate cell (e.g., cell 131) are met, terminal device 120 may establish a dual connection with network device 110 and network device 130. This process of SN addition is sometimes referred to as conditional PSCell addition (CPA).

[0053] In some scenarios, terminal device 120 may establish dual connections with network devices 110 and 130. Network device 110 functions as the Network Manager (MN), and network device 130 functions as the Network Signaling (SN). As terminal device 120 moves, the SN serving terminal device 120 may change 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 process of PSCell change may be referred to as CPC.

[0054] In some scenarios, after a terminal device is configured for conditional reconfiguration and subsequent CPCs are enabled, and before at least one execution condition is met for a candidate PSCell, terminal device 120 may receive a radio resource control (RRC) reconfiguration message from network device 110, including reconfigurationWithSync for SCG, and terminal device 120 may perform a modification or addition of a PSCell accordingly. This procedure is referred to as legacy PSCell modification or addition. For example, after the legacy PSCell modification or addition procedure, the SN serving terminal device 120 is network device 140.

[0055] After the above CPA, CPC, or legacy PSCell modification or additional procedure, terminal device 120 does not release the conditional reconfiguration to support subsequent CPAC and continues to perform conditional reconfiguration evaluation. As terminal device 120 moves further, if the conditions of another candidate cell (e.g., cell 151) are met, the SN serving terminal device 120 may change from network device 140 to network device 150 (hereinafter also referred to as target SN 150). This process of SN change is sometimes referred to as subsequent CPC.

[0056] As shown in Figure 1, if terminal device 120 moves further, terminal device 120 may move out of the coverage of the SN. Network device 110 (i.e., MN) may 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 the subsequent CPAC and may continue to perform the conditional reconfiguration evaluation for the subsequent CPA.

[0057] Continuing 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 may be able to establish a dual connection with network device 110 and network device 140. This process may be referred to as a subsequent CPA.

[0058] Embodiments of this disclosure provide a communication solution for subsequent CPAC to enhance subsequent CPAC procedures. The solution is described in relation to Figures 2 to 4 below.

[0059] Example implementation of L2 handling In some scenarios, the DRB bearer type may or may not change during subsequent CPAC. Depending on whether the bearer type changes or not, different L2 handling (e.g., PDCP re-establishment or recovery, or RLC re-establishment) may be required. However, in the case of candidate PSCell, whether the bearer type changes or not depends on the movement trajectory of the terminal device for subsequent CPAC. Therefore, it is not possible to configure L2 handling in RRC signaling as in conventional CPAC.

[0060] With this in mind, embodiments of the present disclosure provide a solution for L2 handling for subsequent CPACs. This solution is described in reference to Figure 2 below. Figure 2 is a schematic diagram showing an exemplary process 200 for a subsequent CPAC according to embodiments of the present disclosure. For illustrative purposes, process 200 is described with reference to Figure 1. Process 200 may include a terminal device 120 and a network device 110. In this example, the network device 110 is an MN serving the terminal device 120.

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

[0062] In some embodiments, if the execution conditions of a candidate PSCell (e.g., cell 142) are met after a CPA, CPC, or legacy PSCell modification or addition procedure, the terminal device 120 may determine that a subsequent CPC will be executed. In some embodiments, if the execution conditions of a candidate PSCell (e.g., cell 141) are met after an SN release after a CPA, CPC, or legacy PSCell modification or addition procedure, the terminal device 120 may determine that a subsequent CPA will be executed.

[0063] If it determines that a subsequent CPAC is to be executed, the terminal device 120 may determine whether the bearer type of the DRB is changed for the subsequent CPAC (220). In other words, when a subsequent CPAC is executed, the terminal device 120 can determine whether the bearer type of one DRB has been changed.

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

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

[0066] Continuing to refer to Figure 2, if the bearer type of the DRB is changed, the terminal device 120 may perform L2 handling (also referred to herein as the first operation) (230). In some embodiments, if the bearer type of the DRB is changed, the terminal device 120 may re-establish the PDCP entity of the DRB.

[0067] In some embodiments, if the bearer type of the DRB is changed and the PDCP entities of the DRB are not configured with encryption disabled, the terminal device 120 can configure the PDCP entities of the DRB using an encryption algorithm and a key for encrypting data associated with a master key or secondary key. The master key or secondary key may be indicated in the key 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, when the bearer type of the DRB is changed and the PDCP entity of the DRB is configured with integrity protection, the terminal device 120 can configure the PDCP entity with an integrity protection algorithm and a key for protecting the integrity of data associated with a master key or secondary key. The master key or secondary key may be indicated in the key used for the DRB (e.g., keyToUse).

[0069] In some embodiments, if the DRB bearer type is changed, the terminal device 120 may re-establish at least one RLC entity for at least one RLC bearer associated with the DRB. Note that the above actions when the DRB bearer type is changed may be performed separately or in any combination.

[0070] Continuing to refer to Figure 2, if the bearer type of the DRB has not been changed, the terminal device 120 may perform L2 handling (also referred to herein as the second operation) (240). In some embodiments, if the bearer type of 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 of the DRB has not been changed, the terminal device 120 may re-establish at least one RLC entity for at least one SCG RLC bearer associated with the DRB.

[0071] In some embodiments, the network device 110 can restrict or avoid bearer type changes during subsequent CPACs based on an appropriate configuration.

[0072] In process 200, during subsequent CPAC, terminal devices can perform L2 handling in the event of a bearer type change without explicit instructions from the network. Therefore, lossless operation can be supported for AM DRB.

[0073] Exemplary implementation forms of inter-SN or inter-SN successor CPC In some scenarios, whether a terminal device performs security key updates and L2 handling during a subsequent CPC depends on whether the subsequent CPC is an inter-SN subsequent CPC or an intra-SN subsequent CPC. However, it remains unclear how to determine whether a subsequent CPC is an inter-SN subsequent CPC or an intra-SN subsequent CPC, and what L2 handling should be performed for either an inter-SN subsequent CPC or an intra-SN subsequent CPC.

[0074] With this in mind, embodiments of the present disclosure provide a solution for security key renewal and L2 handling for subsequent CPCs. The solution is described in reference to Figure 3 below. Figure 3 shows a schematic diagram illustrating an exemplary process 300 of a subsequent CPC according to embodiments of the present disclosure. For illustrative purposes, process 300 is described with reference to Figure 1. Process 300 may include a terminal device 120 and a network device 110. In this example, the network device 110 is an MN serving the terminal device 120.

[0075] As shown in Figure 3, the terminal device 120 can determine that a subsequent CPC from the first cell to the second cell is to be performed (310). In some embodiments, the network device 110 may send the terminal device 120 a configuration of a subsequent CPAC (e.g., a conditional reconfiguration) that includes the execution conditions for the subsequent CPAC for a set of candidate PSCells (311). The terminal device 120 can perform a conditional reconfiguration evaluation based on the execution conditions (312). After a CPA or CPC or legacy PSCell modification or addition procedure, the terminal device 120 is changed to the first cell (e.g., cell 142). The terminal device 120 may determine that a subsequent CPC from cell 142 to cell 151 is to be performed if the execution conditions for the candidate PSCell (i.e., the second cell (e.g., cell 151)) are met.

[0076] If the terminal device 120 determines to perform a subsequent CPC, that is, if it executes a subsequent CPC, it may determine whether the subsequent CPC is an inter-SN subsequent CPC or an intra-SN subsequent CPC. In some embodiments, the determination may be based on the identity (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 source PSCell (i.e., the first cell) maintained by the terminal device 120.

[0077] Continuing to refer to Figure 3, the terminal device 120 can determine whether the first cell (i.e., the serving PSCell or source PSCell) is a candidate PSCell for a subsequent CPAC (320). In some embodiments, if the first cell is a candidate PSCell that supports a subsequent CPAC, the terminal device 120 can set the ID value of the serving cell as the ID value configured for the candidate PSCell. If the first cell is not a candidate PSCell for a subsequent CPAC, the terminal device 120 can perform the operation according to embodiments of the present disclosure.

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

[0079] In some embodiments, terminal device 120 may receive a configuration of a first ID value from network device 110 (i.e., MN) (331). Alternatively, terminal device 120 may receive a configuration of a 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. Upon receiving the configuration, terminal device 120 may set the ID value maintained for the serving PSCell or source PSCell as 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 a UE variable.

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

[0081] Upon determining the first ID value, the terminal device 120 can compare the first ID value with the second ID value of the second cell (340). If the first ID value is the same as the second ID value, the terminal device 120 can determine that the subsequent CPC is an intra-SN subsequent CPC. If the first ID value is different from the second ID value, the 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 source PSCell is the same as the ID value of the target candidate PSCell, the terminal device 120 determines that the subsequent CPC is an intra-SN. If the ID value of the serving PSCell or source PSCell is different from the ID value of the target candidate PSCell, the terminal device 120 determines that the subsequent CPC is an 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] Continuing to refer to Figure 3, in some embodiments, if the first cell (i.e., serving PSCell or source PSCell) is not a candidate PSCell for a subsequent CPAC, the terminal device 120 may determine that the subsequent CPC is an inter-SN subsequent CPC (350). In some alternative embodiments, if the first cell (i.e., serving PSCell or source PSCell) is not a candidate PSCell for a subsequent CPAC, the terminal device 120 may determine that the subsequent CPC is an intra-SN subsequent CPC (360).

[0084] In some embodiments, if no ID values ​​are configured in the first and second cells, the terminal device 120 can determine that the subsequent CPC is an inter-SN subsequent CPC. That is, the terminal device 120 may determine that the subsequent CPC is an inter-SN if no ID values ​​are configured in at least one of the serving PSCell / source PSCell or target candidate PSCell. In some alternative embodiments, if no ID values ​​are configured in the first and second cells, the terminal device 120 can determine that the subsequent CPC is an intra-SN subsequent CPC. That is, the terminal device 120 may determine that the subsequent CPC is an intra-SN if no ID values ​​are configured in at least one of the serving PSCell / source PSCell or target candidate PSCell.

[0085] In some embodiments, for each ID value, the network device 110 may configure a list of security key counters (e.g., sk counters) to derive or update the secondary key. Upon receiving the list of security key counters, the terminal device 120 may store the list of security key counters for each ID value in a UE variable. For inter-SN successor CPCs and intra-SN successor CPCs, the terminal device may perform different operations for security key updates and L2 handling.

[0086] Continuing to refer to Figure 3, if the subsequent CPC is an inter-SN subsequent CPC, the terminal device 120 can perform a security key update (370). 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 may discard the used security key counter from a stored list of security key counters associated with the ID value of the target candidate PSCell or the updated ID value of the serving PSCell.

[0087] Continuing to refer to Figure 3, if the subsequent CPC is an inter-SN subsequent CPC, the terminal device 120 can perform L2 handling (380).

[0088] In some embodiments, for SN-terminated DRBs (e.g., for each SN-terminated DRB), the terminal device 120 may re-establish the DRB's PDCP entity. The SN-terminated DRB is a DRB with a secondary keyToUse. In some embodiments, if the DRB's PDCP entity is not configured with encryption disabled, the terminal device 120 may configure the PDCP entity with an encryption algorithm and key for encrypting data associated with the secondary key. That is, the encryption configuration may be applied to all subsequent PDCP PDUs received and transmitted by the terminal device 120. In some embodiments, if the DRB's PDCP entity is configured with integrity protection, the terminal device 120 may configure the PDCP entity with an integrity protection algorithm and a key for integrity protection of data associated with the secondary key. That is, the integrity protection configuration may be applied to all subsequent PDCP PDUs received and transmitted by the terminal device 120. In some embodiments, the terminal device 120 may re-establish 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 implementable.

[0089] In some embodiments, for at least one signaling radio bearer (SRB) between the SN (e.g., network device 150) corresponding to a 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), for example for SRB3, the terminal device 120 may re-establish 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 encryption of 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 a message used to indicate the successful completion of the encryption configuration procedure. 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 a message used to indicate the successful completion of the integrity protection configuration procedure. In some embodiments, the terminal device 120 may re-establish 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 implementable.

[0090] In some embodiments, for each MN-terminated DRB (for example, for each MN-terminated DRB), the terminal device 120 may re-establish 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 having keyToUse as the master.

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

[0092] Continuing to refer to Figure 3, if the subsequent CPC is an intra-SN subsequent CPC, the terminal device 120 can perform L2 handling (390). In some embodiments, for SN-terminating DRBs (e.g., for each SN-terminating DRB), the terminal device 120 may trigger the PDCP entity of the DRB to perform data recovery. In some embodiments, the terminal device 120 may re-establish at least one RLC entity for at least one SCG RLC bearer associated with the DRB. The SN-terminating DRB is a DRB with keyToUse which is secondary.

[0093] In some embodiments, for SRBs between an SN (e.g., network device 150) and a terminal device 120 (e.g., each direct SRB between the SN and the terminal device 120), for example, SRB3, the terminal device 120 can trigger the PDCP entity of the SRB to perform service data unit (SDU) deactivation. In some embodiments, the terminal device 120 can re-establish at least one RLC entity for at least one SCG RLC bearer associated with the SRB.

[0094] In some embodiments, for each MN-terminated DRB (for example, for each MN-terminated DRB), the terminal device 120 may re-establish 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 having keyToUse as the master.

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

[0096] In some embodiments, when the ID value of the serving cell is available during the execution of a subsequent CPC, the terminal device 120 may ignore the information element (IE) for PDCP re-establishment (e.g., reestablishPDCP IE), the IE for PDCP recovery (e.g., recoveryPDCP IE), and the IE for PDCP discard (e.g., discardOnPDCP IE) configured for the SN-terminated DRB and the direct SRB between the SN and the terminal device 120 (e.g., SRB3). In some embodiments, for the MN-terminated DRB, the terminal device 120 may re-establish at least one RLC entity for at least one SCG RLC bearer associated with the DRB. In some embodiments, for the MCG SRB or direct SRB between the MN and the terminal device 120 (e.g., SRB1, SRB2), the terminal device 120 may re-establish at least one RLC entity for at least one SCG RLC bearer associated with the SRB. In some embodiments, the terminal device 120 may re-establish RLC entities for all SCG RLC bearers.

[0097] In process 300, during subsequent CPAC, terminal devices can perform different actions for security key updates and L2 handling depending on whether it is an intra-SN subsequent CPC or an inter-SN subsequent CPC.

[0098] Exemplary implementation of execution conditions for subsequent CPCs In some scenarios, for subsequent CPACs initiated by an SN, the execution conditions for subsequent CPCs can be generated by the candidate SN. However, how the execution conditions for subsequent CPCs are generated remains unclear.

[0099] With this in mind, embodiments of the present disclosure provide a solution for configuring the execution conditions of a subsequent CPAC. This solution is described in reference to Figure 4 below. Figure 4 is a schematic diagram showing another exemplary process 400 of a subsequent CPAC according to embodiments of the present disclosure. For illustrative purposes, process 400 is described with reference to Figure 1. Process 400 may include a terminal device 120 and network devices 110 and 140. In this example, network device 110 is an MN providing services to terminal device 120, and network device 140 is a target candidate SN.

[0100] As shown in Figure 4, network device 110 (i.e., MN) may send an SN addition request message to each of the candidate SNs (e.g., network device 140) at 410. The SN addition request message may include a list of recommended candidate PSCells for the candidate SN and candidate PSCells for other candidate SNs (e.g., network device 150).

[0101] Continuing to refer to Figure 4, network device 140 (i.e., target candidate SN) may send an SN addition request acknowledgment message to network device 110 (i.e., MN) at 420. The SN addition request acknowledgment message may include execution conditions for a subsequent CPC from one of the candidate PSCells of target candidate SN (e.g., cell 142) to another candidate PSCell of target candidate SN (e.g., cell 143) or another candidate PSCell of another target candidate SN (e.g., cell 151).

[0102] As shown in Figure 4, network device 110 (i.e., MN) can transmit a successor CPAC configuration, including the execution conditions for the successor CPC received from network device 140, to terminal device 120 (430). The successor CPAC configuration 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 a first candidate PSCell (e.g., cell 142) to a second set of candidate PSCells. In other words, once an RRC reconfiguration is generated 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 in 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 the subsequent CPC are configured as execution conditions related to the conditional reconstruction of candidate PSCells (e.g., cell 141, cell 151, etc.).

[0105] For illustrative purposes, an exemplary procedure can be described as follows: The MN sends an RRCReconfiguration message to the UE, which includes the CPAC configuration, i.e., an RRCReconfiguration* message and a list of associated execution conditions, where each RRCReconfiguration* message includes the SCG configuration and MCG configuration from the RRCReconfiguration** message received from the candidate SN. The MCG configuration may include execution conditions for subsequent CPCs. Furthermore, the RRCReconfiguration message may also include the updated MCG configuration, as well as NR RRCReconfiguration*** messages generated by the source SN to configure, for example, the required conditional measurements.

[0106] In some embodiments, the MCG configuration may further include instructions to suspend or deactivate one or more configurations in a set of configurations associated with one or more second candidate PSCells. In other words, the MN may include instructions to suspend, deactivate, or disable a conditional reconfiguration in the MCG configuration.

[0107] In some embodiments, if a target candidate SN (e.g., network device 140) does not provide execution conditions for a subsequent CPC from a first candidate PSCell (e.g., cell 142) to a second candidate PSCell (e.g., cell 152), or if the target candidate SN indicates in the SN additional request acknowledgment message that a subsequent CPC from the first candidate PSCell (e.g., cell 142) to the second candidate PSCell (e.g., cell 152) is not supported, the MN may include instructions during MCG configuration to suspend, deactivate, or disable conditional reconfiguration associated with the second candidate PSCell (i.e., cell 152). In some embodiments, the instructions may be included in the conditional reconfiguration associated with the second candidate PSCell (i.e., cell 152).

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

[0109] In some embodiments, the first configuration may include execution conditions for a subsequent CPC from a first candidate PSCell (e.g., cell 142) to a second set of candidate PSCells received from network device 140 (i.e., target candidate SN). In other words, once an RRC reconfiguration is generated 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 a subsequent CPC 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 send the RRC reconfiguration to terminal device 120, which receives the execution conditions for the subsequent CPC and stores them in a UE variable.

[0110] For illustrative purposes, an exemplary procedure can be described as follows: The MN sends an RRCReconfiguration message to the UE, which includes the CPAC configuration, i.e., a list of RRCReconfiguration* messages and associated execution conditions, and execution conditions for subsequent CPCs, with each RRCReconfiguration* message including the SCG configuration and MCG configuration from the RRCReconfiguration** message received from the candidate SN. Furthermore, the RRCReconfiguration message may also include the updated MCG configuration, as well as NR RRCReconfiguration*** messages generated by the source SN to configure, for example, the required conditional measurements.

[0111] Continuing to refer to Figure 4, when a modification or addition to a PSCell is performed to the first candidate PSCell (for example, cell 142), the terminal device 120 may update the execution conditions stored for the second set of candidate PSCells using the execution conditions for subsequent CPCs from the first candidate PSCell to the second set of candidate PSCells (450). That is, in conjunction with the modification or addition of a PSCell to the first candidate PSCell, the terminal device 120 may update or set the execution conditions for conditional reconfiguration associated with other candidate PSCells as execution conditions for subsequent CPCs.

[0112] In some embodiments, a modification or addition to a PSCell may be a conditional modification or addition to a PSCell. In some embodiments, a modification or addition to a PSCell may be an unconditional modification or addition to a PSCell. In other words, upon successful completion of a random access procedure triggered for reconfiguration using synchronization in the SpCell configuration of the SCG, the target PSCell is a candidate PSCell (e.g., cell 142). For example, terminal device 120 may replace the execution conditions for a conditional reconfiguration related to another candidate PSCell (e.g., cell 151) in the UE variables with execution conditions 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 instructions to suspend or deactivate one or more configurations in a set of configurations associated with one or more second candidate PSCells.

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

[0115] For example, if no execution conditions are received to trigger a conditional reconfiguration or a subsequent CPC from a first candidate PSCell (e.g., cell 142) to another conditional reconfiguration or a second candidate PSCell (e.g., cell 152), or if an explicit instruction is received to suspend, deactivate, or disable the other conditional reconfiguration or second candidate PSCell, the terminal device 120 may consider the other conditional reconfiguration or second candidate PSCell (e.g., cell 152) to be disabled, suspended, or deactivated in response to a change or addition of a PSCell to the first candidate PSCell (e.g., cell 142). Alternatively, the terminal device 120 may suspend or deactivate the conditional reconfiguration evaluation for the other conditional reconfiguration or second candidate PSCell (e.g., cell 152).

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

[0117] Using process 400, the generation of execution conditions for subsequent CPCs by candidate SNs can be supported.

[0118] Please understand that the steps and their order in Figures 2-4 are for illustrative purposes only and not limiting. More or fewer steps can also be implemented.

[0119] Example implementation of the method Therefore, embodiments of this disclosure provide communication methods implemented in terminal devices and MNs. These methods will be described below with reference to Figures 5 to 8.

[0120] Figure 5 illustrates exemplary methods 500 of communication implemented in a terminal device according to several embodiments of the present disclosure. For example, method 500 may be implemented in a terminal device 120 as shown in Figure 1. Method 500 may include additional blocks not shown, and / or some of the illustrated blocks may be omitted, and it should be understood that the scope of the present disclosure is not limited in this respect.

[0121] As shown in Figure 5, in block 510, the terminal device 120 determines that subsequent CPAC will be executed.

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

[0123] In block 530, the terminal device 120 performs a first operation. In some embodiments, the first operation may include re-establishing the DRB's PDCP entity. In some embodiments, if the DRB's PDCP entity is not configured with encryption disabled, the first operation may include configuring the PDCP entity with an encryption algorithm and a key for encryption of data associated with a master key or secondary key. In some embodiments, if the DRB's PDCP entity is configured with integrity protection, the first operation may include configuring the PDCP entity with an integrity protection algorithm and a key for integrity protection of data associated with a master key or secondary key. In some embodiments, the first operation may include re-establishing 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 of the DRB is not changed for subsequent CPACs, the terminal device 120 may perform a second action. In some embodiments, the second action may include triggering the PDCP entity of the DRB to perform data recovery. In some embodiments, the second action may include re-establishing at least one RLC entity for at least one SCG RLC bearer associated with the DRB. It should be understood that the second action may include any combination of the above actions.

[0125] In this way, during subsequent CPAC, terminal devices can perform L2 handling in the event of a bearer type change without explicit instructions from the network. Therefore, lossless operation can be supported for AM DRB.

[0126] Figure 6 shows another exemplary method 600 of communication implemented in a terminal device according to some embodiments of the present disclosure. For example, method 600 may be performed in a terminal device 120 as shown in Figure 1. Method 600 may include additional blocks not shown, and / or some blocks shown may be omitted, and it should be understood that the scope of the present disclosure is not limited in this respect.

[0127] As shown in Figure 6, in block 610, the terminal device 120 determines that a subsequent CPC from the first cell to the second cell is to be executed.

[0128] In block 620, the terminal device 120 determines that the first cell is not a candidate PSCell for the subsequent CPC.

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

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

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

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

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

[0134] In some embodiments, if the subsequent CPC is an inter-SN subsequent CPC, the terminal device 120 may derive the secondary key by using a security key counter in the list of security key counters associated with the second identification value and discard a 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 at least one of the following actions with respect to the DRB as an SN-terminating DRB: re-establishing the DRB's PDCP entity; if the DRB's PDCP entity is not configured with encryption disabled, configuring the PDCP entity with an encryption algorithm and a key for encryption of data associated with a secondary key; if the DRB's PDCP entity is configured with integrity protection, configuring the PDCP entity with an integrity protection algorithm and a key for integrity protection of data associated with a secondary key; or re-establishing 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 can perform at least one of the following actions for at least one SRB between the SN corresponding to the second cell and the terminal device: re-establishing 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 re-establishing 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 at least one of the following actions: re-establishing at least one radio link control (RLC) entity for at least one SCG RLC bearer associated with the DRB as the MN-terminating DRB; re-establishing at least one RLC entity for at least one SCG RLC bearer associated with the SRB between the MN and the terminal device; or re-establishing RLC entities for all SCG RLC bearers.

[0138] In some embodiments, if the successor CPC is an intra-SN successor CPC, the terminal device 120 may perform at least one of the following actions: triggering a PDCP entity of the DRB to perform data recovery for the DRB as an SN termination DRB, or re-establishing 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 an intra-SN subsequent CPC, the terminal device 120 may perform at least one of the following actions for an SRB between the SN and the terminal device: triggering the PDCP entity of the SRB to perform SDU deletion, or re-establishing at least one RLC entity for at least one SCG RLC bearer associated with the SRB.

[0140] In some embodiments, if the successor CPC is an intra-SN successor CPC, the terminal device 120 may perform at least one of the following actions: re-establishing 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; re-establishing at least one RLC entity for at least one SCG RLC bearer associated with a DRB as the MN termination DRB; or re-establishing RLC entities for all SCG RLC bearers.

[0141] In this way, during subsequent CPACs, terminal devices can distinguish between intra-SN subsequent CPCs and inter-SN subsequent CPCs. This can facilitate different behaviors for security key updates and L2 handling for intra-SN subsequent CPCs and inter-SN subsequent CPCs.

[0142] Figure 7 shows yet another exemplary method 700 of communication implemented in a terminal device according to some embodiments of the present disclosure. For example, method 700 may be performed in a terminal device 120 as shown in Figure 1. Method 700 may include additional blocks not shown, and / or some blocks shown may be omitted, and it should be understood that the scope of the present disclosure is not limited in this respect.

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

[0144] In some embodiments, the MCG configuration may include execution conditions for a subsequent CPC from a first candidate PSCell to a second candidate PSCell set. In some embodiments, the MCG configuration may further include instructions to suspend or deactivate one or more configurations in a set of configurations associated with one or more second candidate PSCells. In some embodiments, if instructions are received or execution conditions for a subsequent CPAC from a first candidate PSCell to one or more second candidate PSCells are not 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 a first candidate PSCell to a second candidate PSCell set. In some embodiments, when a PSCell is modified or an addition is made to the first candidate PSCell, the terminal device 120 may update the execution conditions stored for the second candidate PSCell set with 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 instructions to interrupt or deactivate one or more configurations within a set of configurations associated with one or more second candidate PSCells. In some embodiments, if instructions are received or no subsequent CPAC execution conditions are received from the first candidate PSCell to one or more second candidate PSCells, the terminal device 120 may interrupt or deactivate one or more configurations within the set of configurations.

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

[0148] Figure 8 illustrates exemplary methods 800 of communication implemented in an MN according to several embodiments of the present disclosure. For example, method 800 may be implemented in a network device 110 as shown in Figure 1. Method 800 may include additional blocks not shown, and / or some of the illustrated blocks may be omitted, and it should be understood that the scope of the present disclosure is not limited in this respect.

[0149] As shown in Figure 8, in block 810, the network device 110 as the MN transmits to the 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 a subsequent CPC from a first candidate PSCell to a second candidate PSCell set. In some embodiments, the MCG configuration may further include instructions to suspend or deactivate one or more configurations in a set of configurations associated with one or more second candidate PSCells.

[0151] In some embodiments, the first configuration may include execution conditions for a subsequent CPC from a first candidate PSCell to a second candidate PSCell set. In some embodiments, the first configuration may further include instructions to suspend or deactivate one or more configurations in a set of configurations associated with one or more second candidate PSCells.

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

[0153] The operation of methods 500, 600, 700, and 800 corresponds to that described with reference to Figures 2 to 4; therefore, please understand that other details will not be repeated here for the sake of brevity.

[0154] Example implementation of a device Figure 9 is a simplified block diagram of a device 900 suitable for implementing an embodiment of the present disclosure. Device 900 can be considered a further exemplary implementation of a terminal device 120 or network device 110 as shown in Figure 1. Therefore, device 900 can be implemented in or as at least part of a terminal device 120 or network device 110.

[0155] As shown in the figure, device 900 includes a processor 910, a memory 920 coupled to the processor 910, a preferred transceiver 940 coupled to the processor 910, and a communication interface coupled to the transceiver 940. At least a portion of program 930 is stored in the memory 910. The transceiver 940 may be for bidirectional or unidirectional communication depending on the requirements. 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, but in practice, the access node referred to in this application may have multiple antennas. The communication interface may represent any interface necessary for communication with other network elements, such as the X2 / Xn interface for bidirectional communication between eNBs / gNBs, the S1 / NG interface for communication between Mobility Management Entity (MME) / Access and Mobility Management Function (AMF) / SGW / UPF and eNBs / gNBs, the Un interface for communication between eNBs / gNBs and relay nodes (RNs), or the Uu interface for communication between eNBs / gNBs and terminal devices.

[0156] It is assumed that program 930, when executed by the associated processor 910, includes program instructions that enable device 900 to operate according to embodiments of the present disclosure as described herein with reference to Figures 1 to 8. Embodiments of the present disclosure may be implemented by computer software executable by the processor 910 of device 900, by hardware, or by a combination of software and hardware. The processor 910 may be configured to implement various embodiments of the present disclosure. Furthermore, a combination of the processor 910 and memory 920 may form processing means 950 adapted to implement various embodiments of the present disclosure.

[0157] The memory 920 may be of any type suitable for a local technology network and may be implemented using any suitable data storage technology, such as non-temporary computer-readable storage media, semiconductor-based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory and removable memory, as non-limiting examples. Although only one memory 920 is shown for device 900, device 900 may have multiple physically separate memory modules. The processor 910 may be of any type suitable for a local technology network and may include, as non-limiting examples, one or more of a general-purpose computer, a dedicated computer, a microprocessor, a digital signal processor (DSP), and a 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 to a clock that synchronizes the main processor.

[0158] In some embodiments, the terminal device includes a circuit configured to perform a first operation which includes determining that a subsequent CPAC is to be performed, re-establishing the DRB's PDCP entity in accordance with the determination that the DRB's bearer type has been changed for the subsequent CPAC, configuring the PDCP entity using an encryption algorithm and a key for encrypting data associated with a master key or secondary key in accordance with the determination that the DRB's PDCP entity is not configured with encryption disabled, configuring the PDCP entity using an integrity protection algorithm and a key for protecting the integrity of data associated with a master key or secondary key in accordance with the determination that the DRB's PDCP entity is configured with integrity protection, or re-establishing at least one RLC entity for at least one RLC bearer associated with the DRB.

[0159] In some embodiments, the terminal device includes a circuit configured to perform an operation that includes determining that a subsequent CPC is performed from a first cell to a second cell, determining a first identification value as the identification value of the serving cell according to the determination that the first cell is not a candidate PSCell for the subsequent CPC, and determining that the subsequent CPC is an inter-SN subsequent CPC or an intra-SN subsequent CPC by comparing the first identification value with the second identification value of 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, the terminal device includes a circuit configured to receive from the MN a first configuration of a subsequent CPAC associated with a first candidate PSCell of candidate SN, the first configuration including a set of configurations, the configurations within the set of configurations including an MCG configuration, the MCG configuration including conditions for executing a subsequent CPC from the first candidate PSCell to a second candidate PSCell set, or the first configuration further including conditions for executing a subsequent CPC from the first candidate PSCell to a second candidate PSCell set.

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

[0162] As used herein, the term “circuit” may refer to a hardware circuit and / or a combination of a hardware circuit and software. For example, a circuit may be a combination of an analog and / or digital hardware circuit and software / firmware. As a further example, a circuit may be any part of a hardware processor having software including digital signal processors, software, and memory, which work together to cause a device such as a terminal device or network device to perform various functions. As yet another example, a circuit may be a hardware circuit and / or processor, such as a microprocessor or a part of a microprocessor, which requires software / firmware for operation, although the software may be absent when not required for operation. As used herein, the term “circuit” also encompasses simply a hardware circuit or processor, or a part of a hardware circuit or processor, and the implementation of its (or their) accompanying software and / or firmware.

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

[0164] This disclosure also provides at least one computer program product tangibly stored in a non-temporary computer-readable storage medium. The computer program product includes computer-executable instructions, such as those contained in a program module, which are executed on a target real or virtual processor within a device to perform the processes or methods described above with reference to Figures 1 to 8. Generally, a program module includes routines, programs, libraries, objects, classes, components, data structures, etc., that perform a specific task or implement a specific abstract data type. The functionality of program modules may be combined or divided among program modules as desired in various embodiments. The machine-executable instructions for a program module may be executed within a local or distributed device. In a distributed device, program modules can be located on both local and remote storage media.

[0165] Program code for performing 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, a dedicated computer, or other programmable data processing device, so that when executed by the processor or controller, the program code implements the functions / operations specified in the flowcharts and / or block diagrams. The program code can run entirely on a machine, partially on a machine, as a standalone software package, partially on a machine and partially on a remote machine, or entirely on a remote machine or server.

[0166] The above program code may be embodied on a machine-readable medium, which may 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 may be a machine-readable signal medium or a machine-readable storage medium. The machine-readable medium may include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatus, or devices, or any preferred combination thereof. More specific examples of machine-readable storage media include electrical connections having one or more wires, portable computer diskettes, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fibers, portable compact disc read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any preferred combination thereof.

[0167] Furthermore, although the operations are described in a specific order, this should not be understood as requiring that such operations be performed in a specific order or sequence, or that all described operations be performed, in order to achieve the desired result. In certain circumstances, multitasking and parallel processing may be advantageous. Similarly, while details of several specific implementations are included in the above description, these should not be interpreted as limitations on the scope of this disclosure, but rather as descriptions of features that may be specific to a particular embodiment. Certain features described in the context of a separate embodiment may also be implemented in combination in a single embodiment. Conversely, various features described in the context of a single embodiment may be implemented separately in multiple embodiments or in any preferred subcombination.

[0168] While this disclosure has been described in language specific to structural features and / or methodological behavior, it should be understood that the disclosure as defined in the attached claims is not necessarily limited to the specific features or behaviors described above. Rather, the specific features and behaviors described above are disclosed as exemplary forms that implement the claims.

Claims

1. Terminal device, The device comprises a processor, and the processor provides the terminal device with It is determined that a subsequent conditional primary secondary cell addition or change (CPAC) will be performed, In accordance with the determination that the bearer type of the data radio bearer (DRB) has been changed for the subsequent CPAC, Re-establishing the packet data convergence protocol (PDCP) entity of the aforementioned DRB, In accordance with the DRB's determination that the PDCP entity is not configured with encryption disabled, the PDCP entity is configured using an encryption algorithm and a key for encrypting data associated with a master key or secondary key. In accordance with the DRB's determination that the PDCP entity is configured with integrity protection, the PDCP entity is configured using an integrity protection algorithm and a key for data integrity protection associated with a master key or secondary key, or Re-establishing at least one RLC entity for at least one radio link control (RLC) bearer associated with the DRB, A terminal device configured to perform a first operation which includes at least one of the following:

2. The aforementioned terminal device further, In accordance with the determination that the bearer type for the DRB has not been changed for the subsequent CPAC, trigger the PDCP entity of the DRB to perform data recovery, or Re-establishing at least one RLC entity for at least one secondary cell group (SCG) RLC bearer associated with the DRB, The terminal device according to claim 1, which can be made to perform a second operation including at least one of the following.

3. The aforementioned terminal device further, In response to a change in the key used in the DRB, it is determined that the bearer type of the DRB has been changed, or The terminal device according to claim 1, wherein it is determined that the bearer type of the DRB has not been changed, in accordance with the fact that the key used in the DRB has not been changed.

4. Terminal device, The device comprises a processor, and the processor provides the terminal device with This involves determining that the subsequent conditional primary secondary cell (PSCell) change (CPC) is executed from the first cell to the second cell, In accordance with the determination that the first cell is not a candidate PSCell for the subsequent CPC, The following steps involve determining a first identification value as the identification value of a serving cell, and comparing the first identification value with the second identification value of the second cell to determine whether the subsequent CPC is an intersecondary node (SN) subsequent CPC or an intra-SN subsequent CPC. The determination that the aforementioned subsequent CPC is the aforementioned interSN subsequent CPC, Determining that the aforementioned subsequent CPC is the aforementioned intra-SN subsequent CPC, Performing an action that includes one of the following, A terminal device configured to perform the following action.

5. The aforementioned terminal device is Determining the first identification value based on the configuration of the first identification value from the master node or secondary node, or By determining the first identification value as the default value, The terminal device according to claim 4, which is capable of determining the first identification value.

6. The aforementioned terminal device is In accordance with the determination that the first identification value is the same as the second identification value, the subsequent CPC is determined to be the intra-SN subsequent CPC, or By determining that the subsequent CPC is the interSN subsequent CPC in accordance with the determination that the first identification value is different from the second identification value, The terminal device according to claim 4, wherein the successor CPC is determined to be the inter-SN successor CPC or the intra-SN successor CPC.

7. The aforementioned terminal device further, The terminal device according to claim 6, wherein, in accordance with the determination that the subsequent CPC is the interSN subsequent CPC, the identification value of the serving cell is replaced with the second identification value.

8. The aforementioned terminal device further, The first cell does not contain the first identification value, or The second cell does not contain the second identification value. Based on at least one of the following, determine that the subsequent CPC is the interSN subsequent CPC, or The first cell does not contain the first identification value, or The second cell does not contain the second identification value. The terminal device according to claim 4, wherein the successor CPC is determined to be the intra-SN successor CPC based on at least one of the following.

9. The aforementioned terminal device further, In accordance with the determination that the subsequent CPC is the inter-SN subsequent CPC, The secondary key is derived by using the security key counter in the list of security key counters associated with the second identification value, The terminal device according to claim 4, which can discard the security key counter from the list of security key counters.

10. The aforementioned terminal device further, In accordance with the determination that the aforementioned subsequent CPC is an inter-SN subsequent CPC, the data radio bearer (DRB) as the SN termination DRB, Re-establishing the packet data convergence protocol (PDCP) entity of the aforementioned DRB, In accordance with the DRB's determination that the PDCP entity is not configured with encryption disabled, the PDCP entity is configured using an encryption algorithm and a key for encrypting data associated with a secondary key. In accordance with the DRB's determination that the PDCP entity is configured with integrity protection, the PDCP entity is configured using an integrity protection algorithm and a key for data integrity protection associated with a secondary key, or Re-establishing at least one RLC entity for at least one radio link control (RLC) bearer associated with the DRB, The terminal device according to claim 4, which can be made to perform an operation including at least one of the following.

11. The aforementioned terminal device further, In accordance with the determination that the subsequent CPC is the inter-SN subsequent CPC, for at least one signaling radio bearer (SRB) between the SN corresponding to the second cell and the terminal device, Re-establishing a packet data convergence protocol (PDCP) entity for at least one of the aforementioned SRBs, Configuring the PDCP entity to apply an encryption algorithm and key for encrypting Radio Resource Control (RRC) signaling associated with a secondary key, Configuring the PDCP entity to apply an integrity protection algorithm and key for protecting the integrity of the RRC signaling associated with the secondary key, or Re-establishing at least one RLC entity for at least one radio link control (RLC) bearer associated with the at least one SRB, The terminal device according to claim 4, which can be made to perform an operation including at least one of the following.

12. The aforementioned terminal device further, In accordance with the determination that the subsequent CPC is the inter-SN subsequent CPC, Re-establishing at least one radio link control (RLC) entity for at least one secondary cell group (SCG) RLC bearer associated with a data radio bearer (DRB) as the master node (MN) terminating DRB. Re-establishing 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 Re-establishing the RLC entity for all SCG RLC bearers, The terminal device according to claim 4, which can be made to perform an operation including at least one of the following.

13. The aforementioned terminal device further, In accordance with the determination that the aforementioned successor CPC is the aforementioned intra-SN successor CPC, the data radio bearer (DRB) as the SN termination DRB, Triggering the packet data convergence protocol (PDCP) entity of the DRB to perform data recovery, or Re-establishing at least one radio link control (RLC) entity for at least one secondary cell group (SCG) RLC bearer associated with the DRB, The terminal device according to claim 4, which can be made to perform an operation including at least one of the following.

14. The aforementioned terminal device further, In accordance with the determination that the subsequent CPC is the intra-SN subsequent CPC, Regarding the signaling radio bearer (SRB) between the SN and the terminal device, trigger the packet data convergence protocol (PDCP) entity of the SRB to perform service data unit (SDU) destruction, or Re-establishing at least one radio link control (RLC) entity for at least one secondary cell group (SCG) RLC bearer associated with the SRB, The terminal device according to claim 4, which can be made to perform an operation including at least one of the following.

15. The aforementioned terminal device further, In accordance with the determination that the subsequent CPC is the intra-SN subsequent CPC, Re-establishing at least one radio link control (RLC) entity for at least one secondary cell group (SCG) RLC bearer associated with at least one signaling radio bearer (SRB) between the master node (MN) and the terminal device, Re-establishing at least one RLC entity for at least one SCG RLC bearer associated with a data radio bearer (DRB) as an MN-terminated DRB, or Re-establishing the RLC entity for all SCG RLC bearers, The terminal device according to claim 4, which can be made to perform an operation including at least one of the following.

16. Terminal device, The device comprises a processor, and the processor provides the terminal device with The master node is configured to receive a first configuration of a subsequent conditional primary secondary cell (PSCell) addition or change (CPAC) associated with a first candidate PSCell of a candidate secondary node (SN), wherein the first configuration includes a set of configurations, and the configurations within the set of configurations include a master cell group (MCG) configuration. The MCG configuration includes execution conditions for a subsequent conditional PSCell change (CPC) from the first candidate PSCell to the second candidate PSCell set, or The first configuration further includes the execution conditions for the subsequent CPC from the first candidate PSCell to the second candidate PSCell set, a terminal device.

17. The aforementioned terminal device further, The terminal device according to claim 16, wherein, in accordance with the determination that a PSCell change or addition is performed to the first candidate PSCell, the execution conditions stored for the set of second candidate PSCells are updated with the execution conditions for the subsequent CPC from the first candidate PSCell to the set of second candidate PSCells.

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

19. The aforementioned terminal device further, The terminal device according to claim 18, which can interrupt or deactivate one or more of the configurations in the set of configurations in accordance with the determination that the instruction has been received or that no execution conditions for the subsequent CPAC have been received from the first candidate PSCell to one or more second candidate PSCells.

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