User device and method for using the user device

Abstract

[0003] Embodiments of the present disclosure relate to a communication method, an apparatus, and a computer-readable medium. In one aspect, when it is determined that a subsequent conditional cell change is to be performed from a source cell to a target cell, a terminal device performs a first set of procedures including at least one of updating security keys associated with the target cell, performing PDCP re-establishment for DRBs and SRBs, or performing RLC re-establishment for the DRBs and SRBs. In this way, UE behavior for supporting selective activation of cell groups is defined.

Description

Technical Field

[0001] Embodiments of the present disclosure relate generally to the field of telecommunications, and more particularly, to a communication method, apparatus, and computer storage medium for selective activation of cell groups.

Background Art

[0002] Currently, the multi-random access technology dual connectivity (MR-DC) with selective activation of cell groups aims to enable subsequent conditional primary secondary cell (PSCell) change (CPC) / conditional PSCell addition (CPA) after a secondary cell group (SCG) change without resetting and re-initializing during the preparation of conditional PSCell change / conditional PSCell addition from the network side. This reduces the signaling overhead and interruption time for SCG changes. However, the solution for subsequent CPC / CPA after the CPC / CPA procedure is still incomplete and needs further research.

Summary of the Invention

Problems to be Solved by the Invention

[0003] Overall, embodiments of the present disclosure provide a communication method, apparatus, and computer storage medium for selective activation of cell groups.

Means for Solving the Problems

[0004] In a first embodiment, a method of communication is provided. The method includes a terminal device determining that a subsequent conditional cell change is to be performed from a source cell to a target cell, and executing a first set of procedures including at least one of updating the security key associated with the target cell, performing Packet Data Convergence Protocol (PDCP) re-establishment for a Data Radio Bearer (DRB) and a Signaling Radio Bearer (SRB), or performing Radio Link Control (RLC) re-establishment for the DRB and the SRB.

[0005] In a second embodiment, a method of communication is provided. The method includes, in a first network device, receiving a message from a terminal device indicating that a conditional cell change is performed from a source cell to a target cell, and transmitting an instruction to a second network device providing the source cell indicating the release of the connection with the terminal device.

[0006] In a third embodiment, a method of communication is provided. The method includes determining in a first network device that a setting for a subsequent conditional cell addition or modification is to be released, and transmitting an instruction indicating the release of the setting for the subsequent conditional cell addition or modification to a second network device that provides candidate cells for the subsequent conditional cell addition or modification.

[0007] In a fourth embodiment, a communication device is provided. The device comprises a processor configured to cause the device to perform a method according to any one of the first to third embodiments of the present disclosure.

[0008] In a fifth embodiment, a computer-readable medium storing instructions is provided. When the instructions are executed on at least one processor, the instructions cause the at least one processor to perform a method according to any one of the first to third embodiments of the present disclosure.

[0009] Other features of this disclosure should be easily understood from the following explanation. [Brief explanation of the drawing]

[0010] The above-mentioned and other objectives, features, and advantages of this disclosure will be further clarified by describing in more detail some embodiments of this disclosure in the attached drawings.

[0011] [Figure 1A] This figure shows an exemplary communication network that can implement some embodiments of the present disclosure.

[0012] [Figure 1B] This diagram shows a schematic representation of network protocol layer entities that may be established for a user plane (UP) protocol stack in devices according to some embodiments of the present disclosure.

[0013] [Figure 1C] This is a schematic diagram showing network protocol layer entities that may be established for a control plane (CP) protocol stack in devices according to some embodiments of the present disclosure.

[0014] [Figure 2] This is a schematic diagram illustrating an exemplary communication process according to an embodiment of the present disclosure.

[0015] [Figure 3] This is a schematic diagram illustrating another exemplary communication process according to an embodiment of the present disclosure.

[0016] [Figure 4]A schematic diagram showing yet another exemplary communication process according to an embodiment of the present disclosure.

[0017] [Figure 5] A diagram showing an exemplary communication method implemented in a terminal device according to some embodiments of the present disclosure.

[0018] [Figure 6] A diagram showing an exemplary communication method implemented in a network device according to some embodiments of the present disclosure.

[0019] [Figure 7] A diagram showing another exemplary communication method implemented in a network device according to some embodiments of the present disclosure.

[0020] [Figure 8] A schematic block diagram of a device suitable for implementing an embodiment of the present disclosure.

[0021] In the figure, the same or similar reference numerals represent the same or similar elements.

Embodiments for Carrying Out the Invention

[0022] Here, the principles of the present disclosure will be explained with reference to some embodiments. It should be understood that these embodiments are described for illustrative purposes only and are intended to assist those skilled in the art in understanding and implementing the present disclosure, without suggesting any limitation to the scope of the present disclosure. The disclosure content described here can be implemented in various ways different from the methods described below.

[0023] In the following description and claims, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present disclosure pertains.

[0024] 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 (PDA), 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 where X represents pedestrians, vehicles, or infrastructure / networks, devices for integrated access and backhaul (IAB), satellite-borne vehicles or aircraft-borne vehicles within non-terrestrial networks (NTN), including high-altitude platforms (HAP) encompassing satellites and unmanned aircraft systems (UAS), augmented reality (AR), and mixed reality (MR). This includes, but is not limited to, Extended Reality (XR) devices that include different types of reality such as Reality, Virtual Reality (VR), Unmanned Aerial Vehicles (UAVs) which are aircraft without human operators and are commonly referred to as drones, devices on High Speed ​​Trains (HST), or image acquisition devices such as digital cameras, sensors, game devices, music storage and playback devices, or internet devices that enable wireless or wired internet access and browsing.The “Terminal Device” may further have “Multicast / Broadcast” capabilities to support V2X applications, transparent IPv4 / IPv6 multicast distribution, IPTV, smart TV, wireless services, wireless software distribution, group communications, and IoT applications where public safety and mission are of paramount importance. It may also incorporate one or more Subscriber Identity Modules (SIMs), known as multi-SIMs. The term “Terminal Device” may be used interchangeably with UE, mobile station, subscriber station, mobile terminal, user terminal, or wireless device.

[0025] As used herein, the term "network device" refers to a device capable of providing or hosting a cell or coverage on which terminal devices can communicate. Examples of network devices include, but are not limited to, Node B (NodeB or NB), Evolutionary 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), IAB nodes, low-power nodes such as femtonodes and piconodes, and Reconfigurable Intelligent Surfaces (RIS).

[0026] Terminal devices or network devices may possess artificial intelligence (AI) or machine learning capabilities. Generally, this includes trained models derived from large amounts of data collected for specific functions, which can be used to predict certain information.

[0027] Terminal or network devices may operate on several frequency ranges, such as FR1 (410 MHz to 7125 MHz), FR2 (24.25 GHz to 71 GHz), frequency bands greater than 100 GHz, and terahertz (THz). Furthermore, they can operate on licensed / unlicensed / shared spectrum. Terminal devices may have two or more connections to network devices under multi-radio dual connectivity (MR-DC) application scenarios. Terminal or network devices can operate in full-duplex, flexible-duplex, and cross-split-duplex modes.

[0028] Embodiments of this disclosure may be implemented, for example, in test equipment such as signal generators, signal analyzers, spectrum analyzers, network analyzers, test terminal devices, test network devices, and channel emulators.

[0029] In one embodiment, the 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 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 regarding different RATs may 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 regarding the settings of the terminal device set by the second network device may be transmitted from the second network device via the first network device. Information regarding the reconfiguration of terminal devices set by the second network device may be transmitted from the second network device directly to the terminal devices or via the first network device.

[0030] The singular forms “one” and “the foregoing” used herein also include the plural form unless explicitly indicated in the context. The term “including” and its variations should be understood as non-restrictive, meaning “including, but not limited to.” The term “based on” should be understood as “at least partially based on.” The terms “one embodiment” and “embodiment” should be understood as “at least one embodiment.” The term “another embodiment” should be understood as “at least one other embodiment.” Terms such as “first,” “second,” etc., may refer to different or identical subjects. The following may include other explicit and implicit definitions.

[0031] In some examples, values, procedures, or devices are referred to as “best,” “lowest,” “highest,” “minimum,” “maximum,” etc. Such descriptions are intended to show that a choice can be made from many commonly used functional alternatives, and it should be understood that such a choice does not necessarily have to be better, smaller, higher, or otherwise preferable than other choices.

[0032] In the context of this application, the term “selective activation of a cell group” may be used interchangeably with “subsequent CPC / CPA,” “subsequent conditional cell change or addition,” “subsequent conditional handover,” “selective activation of an SCG,” “subsequent SCG change,” or “subsequent cell group change or addition.” In the context of this application, the term “cell change or addition” may be used interchangeably with “reconfigurationWithSync for an SCG or Master Cell Group (MCG).” In the context of this application, the term “PSCell” refers to an SCG SpCell, the term “PCell” refers to an MCG SpCell, and “SpCell” refers to a primary cell of an SCG or MCG.

[0033] We agreed to define NR-DC mechanisms and procedures involving the selective activation of cell groups (at least for SCGs) via Layer 3 (L3) extensions. Specifically, we agreed to allow subsequent cell group changes after a cell group has been changed without the need for CPC / CPA resetting and reconfiguration. We also agreed that selective activation of cell groups by CPA will be supported.

[0034] However, it is unclear how Layer 2 (L2) and security measures will be determined for subsequent CPCs. Furthermore, it is unclear how the settings for selective activation of cell groups will be released on the network side. Additionally, it is unclear how subsequent CPAs will be supported after the SCG is released.

[0035] In view of this, embodiments of the present disclosure provide a solution for the selective activation of cell groups. In one embodiment, when it is determined that a subsequent conditional cell change is to be performed from a source cell to a target cell, the terminal device performs a set of procedures including at least one of updating the security key associated with the target cell, re-establishing the Packet Data Convergence Protocol (PDCP) for the Data Radio Bearer (DRB) and Signaling Radio Bearer (SRB), or re-establishing Radio Link Control (RLC) for the DRB and SRB. Thus, the UE behavior for the selective activation of cell groups can be clarified.

[0036] In another embodiment, when a message indicating a conditional cell change from a source cell to a target cell is received from a terminal device, the network device sends an instruction to another network device that provided the source cell to release the connection with the terminal device. This makes it clear the network behavior of releasing the connection with the terminal device for the selective activation of the cell group.

[0037] In yet another embodiment, when it is determined that the setting for subsequent conditional cell modification or addition is to be released, the network device sends an instruction indicating the release of the setting for subsequent conditional cell modification or addition to another network device that provides candidate cells for subsequent conditional cell modification or addition. In this way, the network behavior of releasing the setting for selective activation of cell groups can be made clear.

[0038] It should be understood that this solution may be applied to SCG changes or MCG changes. For convenience, embodiments of this disclosure will be described using a subsequent CPC as an example.

[0039] The principles and embodiments of this disclosure will be described in detail below with reference to the attached drawings. Examples of communication networks

[0040] Figure 1A is a schematic diagram of an exemplary communication network 100A that can implement embodiments of the present disclosure. As shown in Figure 1A, the communication network 100A 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 provided with services by the network device 110.

[0041] The communication network 100A may further 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. The number of cells is not limited to three. Network device 1 More or fewer cells will also be set for 10.

[0042] Assume that terminal device 120 is capable of establishing dual connectivity (i.e., simultaneous connection) with two network devices. For example, network device 110 may function as an MN (hereinafter also referred to as MN 110 for convenience), and network device 130 may function as an SN (hereinafter also referred to as SN 130 for convenience). Although only cell 111 is shown, MN 110 may provide multiple cells, which 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 may form an SCG for terminal device 120. Assume that cell 131 is the primary cell (i.e., PSCell) in the SCG.

[0043] SN 130 may communicate with terminal device 120 via a channel such as a wireless communication channel. Similarly, MN 110 may also communicate with terminal device 120 via a channel such as a wireless communication channel. SN 130 may communicate with MN 110 via a control plane interface such as Xn-C. MN 110 may communicate with core network 160 such as AMF 162 via a control plane interface such as NG-C. SN 130 may further communicate with MN 110 via a user plane interface such as Xn-U, and with core network 160 such as UPF 161 via a user plane interface such as NG-U.

[0044] The number of devices or cells in Figure 1A is given for illustrative purposes only and should be understood as not implying any limitation to this disclosure. The communication network 100A may involve any appropriate number of network devices and / or terminal devices and / or cells suitable for carrying out embodiments of this disclosure.

[0045] Communication in the communication network 100A may conform to any appropriate standard, including but not limited to Global System for Mobile Communication (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 performed in accordance with any generation of communication protocols that are 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 networks, or sixth-generation (6G) networks.

[0046] Communication from terminal device 120 toward network devices 110, 130, 140, or 150 is called UL communication, and communication in the reverse direction from network devices 110, 130, 140, or 150 toward terminal device 120 is called DL communication. Terminal device 120 can move between cells of network devices 110, 130, 140, or 150, and possibly other network devices. In UL communication, terminal device 120 may transmit UL data and control information to network devices 110, 130, 140, or 150 via the UL channel. In DL communication, network devices 110, 130, 140, or 150 may transmit DL data and control information to terminal device 120 via the DL channel.

[0047] Communication in the communication network 100A may be carried out according to the UP and CP protocol stacks. Generally speaking, in the case of a communication device (e.g., a terminal device or a network device), there may be multiple entities of the network protocol layer within the protocol stack, and these entities may be configured to perform corresponding processes for data or signaling transmitted from and received by the communication device. Figure 1B is a schematic diagram 100B showing network protocol layer entities that may be established for the UP protocol stack in a device according to some embodiments of the present disclosure. For convenience, the following explanation will use communication between a terminal device 120 and a network device 110 as an example. It should be understood that the following explanation is also applicable to communication between a terminal device 120 and network devices 130, 140, or 150.

[0048] As shown in Figure 1B, in UP, each of the terminal device 120 and the network device 110 may include one or more entities in higher layers (L2 and Layer 3 (L3) or higher layers), including L1 layer entities, i.e., physical (PHY) layer entities (also called PHY entities), media access control (MAC) layer entities (also called MAC entities), radio link control (RLC) layer entities (also called RLC entities), packet data convergence protocol (PDCP) layer entities (also called PDCP entities), and service data application protocol (SDAP) layer entities (also called SDAP entities, which are established in 5G and subsequent generations of networks). In some cases, the PHY, MAC, RLC, PDCP, and SDAP entities are in a stacked structure.

[0049] Figure 1C is a schematic diagram 100C showing network protocol layer entities that may be established for a CP protocol stack in an apparatus according to some embodiments of the present disclosure. As shown in Figure 1C, in CP, each of the terminal device 120 and the network device 110 may include one or more entities of the upper layers (L2 and L3 layers), including L1 layer entities, i.e., PHY layer entities (also referred to as PHY entities), MAC layer entities (also referred to as MAC entities), RLC layer entities (also referred to as RLC entities), PDCP layer entities (also referred to as PDCP entities), and Radio Resource Control (RRC) layer entities (also referred to as RRC entities). The RRC layer may further be referred to as the Access Stratum (AS) layer, and for that purpose, the RRC entities may further be referred to as AS entities. As shown in Figure 1C, the terminal device 120 may further include entities of the Non-Access Stratum (NAS) layer (also referred to as NAS entities). The network-side NAS layer is located within the core network (CN: Core Network, not shown), rather than within the network device itself. In some cases, these entities are arranged in a stacked structure.

[0050] Generally, communication channels are divided into logical channels, transmission channels, and physical channels. A physical channel is the channel through which the PHY layer actually transmits information. For example, a physical channel may include a physical uplink control channel (PUCCH), a physical uplink shared channel (PUSCH), a physical random-access channel (PRACH), a physical downlink control channel (PDCCH), a physical downlink shared channel (PDSCH), and a physical broadcast channel (PBCH).

[0051] The transmit channel is the channel between the PHY layer and the MAC layer. For example, the transmit channel may include a broadcast channel (BCH), a downlink shared channel (DL-SCH), a paging channel (PCH), an uplink shared channel (UL-SCH), and a random access channel (RACH).

[0052] A logical channel is a channel between the MAC layer and the RLC layer. For example, a logical channel may include a dedicated control channel (DCCH), a common control channel (CCCH), a paging control channel (PCCH), a broadcast control channel (BCCH), and a dedicated traffic channel (DTCH).

[0053] Generally, the channel between the RRC layer and the PDCP layer is referred to as a radio bearer. The terminal device 120 may be configured to have at least one DRB for carrying data plane data and at least one SRB for carrying control plane data.

[0054] In some embodiments, the network device 110 may set a conditional reset for a set of candidate cells in the terminal device 120. This conditional reset may indicate that a subsequent CPC has been activated.

[0055] Assume that cells 131-133, 141-143, and 151-153 are set as candidate cells for terminal device 120. In some scenarios, terminal device 120 may initially communicate only with network device 110. When terminal device 120 moves, if the conditions for a candidate cell (e.g., cell 131) are met, terminal device 120 may be allowed to establish dual connectivity with network device 110 and network device 130. This SN addition process may be referred to as CPA.

[0056] In some scenarios, terminal device 120 may establish dual connectivity with network devices 110 and 130. Network device 110 functions as MN, and network device 130 functions as SN. When terminal device 120 moves, if conditions are met for another candidate cell (e.g., cell 142), the SN providing service to terminal device 120 may change from network device 130 (also referred to as source SN or current SN 130) to network device 140 (also referred to as target SN 140). This PSCell change process may be referred to as CPC. In some scenarios, after conditional reconfiguration is set for terminal device and subsequent CPCs are enabled, and before at least one execution condition is met for any candidate PSCell, terminal device 120 may receive an RRC reconfiguration message containing reconfigurationWithSync from network device 110 and perform a PSCell change or addition accordingly. This procedure is referred to as conventional PSCell change or addition. As an example, the network device 140 is the service SN that provides services to the terminal device 120 after a conventional PSCell modification or addition procedure.

[0057] If, after the above CPA, CPC, or conventional PSCell change / addition procedure, the terminal device 120 moves further and conditions for another candidate cell (e.g., cell 152) are met, the SN providing service to the terminal device 120 may change from network device 140 to network device 150 (also referred to as target SN 150). This SN change process may be referred to as a subsequent CPC. The subsequent CPC may be executed several more rounds as the terminal device 120 moves further.

[0058] When terminal device 120 moves further, it may move outside the coverage of network devices 130, 140, or 150. In this case, all SNs may be released. When terminal device 120 re-enters the coverage of network devices 130, 140, or 150, SN addition may be performed. This SN addition process may be referred to as a subsequent CPA. When terminal device 120 moves further, several more rounds of subsequent CPAs may be performed.

[0059] Embodiments of this disclosure provide a solution for selective activation of cell groups, for example, for communication for subsequent CPCs or subsequent CPAs. Example implementation of UE behavior for selective activation of cell groups

[0060] Traditionally, whether a UE performs PDCD re-establishment, PDCP recovery, PDCP SDU discarding, RLC re-establishment, and security key renewal is based on explicit instructions in the RRCReconfiguration message. However, in the case of a subsequent CPC, the network cannot predict the UE's movement trajectory and therefore cannot properly configure these behaviors within the RRCReconfiguration message.

[0061] Embodiments of this disclosure provide a solution for selective activation of cell groups to solve the above and other potential problems. For convenience, this solution is described below with reference to Figure 2.

[0062] Figure 2 is a schematic diagram showing an exemplary communication process 200 according to an embodiment of the present disclosure. For illustrative purposes, the process 200 will be described with reference to Figure 1A. The process 200 may involve a terminal device 120 and network devices 110, 130, and 140 as shown in Figure 1A. In this example, network device 110 is an MN (hereinafter referred to as MN 110 for convenience) that provides services to terminal device 120, network device 140 is a potential target SN (hereinafter referred to as SN 140 for convenience) that provides services to terminal device 120, and cell 143 is a target PSCell. Assume that network device 130 is a source SN (hereinafter referred to as SN 130 for convenience) that provides services to terminal device 120, and that terminal device 120 is being serviced by cell 131 (i.e., source PSCell).

[0063] As shown in Figure 2, the terminal device 120 may receive a setting for the selective activation of a cell group (e.g., a conditional reset) (210). In some embodiments, for example, the terminal device 120 may receive a conditional reset from the MN 110 (211).

[0064] In some embodiments, the settings for selective activation of a cell group may represent a set of settings for a set of candidate cells (e.g., cells 132, 133, 141, 142, 143, 151, 152, and 153) and cell modification conditions associated with each candidate cell in the set of candidate cells. In some embodiments, the settings for selective activation of a cell group may further include cell addition conditions associated with each candidate cell in the set of candidate cells. It should be understood that such settings may include any appropriate information, and this disclosure is not limiting this aspect.

[0065] The terminal device 120 may determine that the subsequent conditional cell change will be performed from a source PSCell (cell 131) to a target PSCell (e.g., cell 143) (220). For example, the terminal device 120 may perform a measurement on a set of candidate cells and determine that cell 143 satisfies the cell change condition. The terminal device 120 may then decide to perform the SN change to cell 143 by applying the settings associated with cell 143.

[0066] The terminal device 120 may execute a set of procedures for L2 and security measures (for convenience, also referred to here as the first set of procedures) during the subsequent conditional PSCell modification (230).

[0067] In some embodiments, the first set of procedures may include updating the security key (also referred to as the secondary key) associated with the target PSCell. In some embodiments, the set of procedures may include performing PDCP re-establishment for the DRB and SRB, for example, for all DRBs and all SRBs. In some embodiments, the set of procedures may include performing RLC re-establishment for the DRB and SRB, for example, for all DRBs and all SRBs. That is, either the PDCP re-establishment procedure or the RLC re-establishment procedure can be directly triggered by the RRC layer of the terminal device 120 without any instructions in the RRCReconfiguration message. It should be understood that the first set of procedures may include any appropriate combination of the above procedures.

[0068] Referring to Figure 2, in some embodiments, if a subsequent conditional cell change is performed, the terminal device 120 may directly execute the first set of procedures (231).

[0069] In some alternative embodiments, the terminal device 120 may determine whether the source PSCell and target PSCell were provided by different network devices (232).

[0070] In some embodiments, the terminal device 120 may determine the cell identity and network device identity length information of the source PSCell and target PSCell, and based on the cell identity and network device identity length information of the source PSCell and target PSCell, determine whether the source PSCell and target PSCell were provided by different network devices.

[0071] For example, terminal device 120 may obtain information on the cell identity (e.g., cellIdentity) and network device identity length (e.g., gNB-ID-Length) of the source PSCell from the system information (e.g., PLMN-IdentityInforList information element (IE)) of SN 130 which provides the source PSCell (e.g., cell 131), and determine the cell identity and network device identity length of the target PSCell via system information from SN 140 which provides the target PSCell (e.g., cell 143).

[0072] The terminal device 120 may determine the identity of the SN 130 providing the source PSCell (for convenience, also referred to here as the first identity) based on the cell identity and network device identity length information of the source PSCell, and may determine the identity of the SN 140 providing the target PSCell (for convenience, also referred to here as the second identity) based on the cell identity and network device identity length information of the target PSCell. If the first identity is different from the second identity, the terminal device 120 may determine that the source PSCell and target PSCell were provided by different network devices. If the first identity is the same as the second identity, the terminal device 120 may determine that the source PSCell and target PSCell were provided by the same network device.

[0073] In some embodiments, terminal device 120 may determine information associated with a set of candidate cells for a subsequent conditional cell change, and based on the information associated with the set of candidate cells, determine whether the source PSCell and target PSCell were provided by different network devices. In some embodiments, the information may be information about a cell group, gNB, or SN associated with the candidate cells. For example, terminal device 120 may obtain the information associated with a set of candidate cells from a setting for selective activation of cell groups (e.g., a conditional reset). In other words, network device 110 may set the information within or in conjunction with a conditional reset that supports selective activation of cell groups. Of course, any other suitable method is also possible.

[0074] In some embodiments, the information associated with a pair of candidate cells may include at least one of the following: the identity of the cell group associated with a candidate cell in the pair; the identity of the network device associated with the candidate cell (e.g., gNB ID); or the identity of the SN associated with the candidate cell. It should be understood that any other appropriate information is also possible. Such information may be useful in determining whether to execute a set of L2 procedures and / or whether to update the security key associated with the target PSCell.

[0075] If the source PSCell and target PSCell are associated with different cell groups or network devices, the terminal device 120 may determine that the source PSCell and target PSCell were provided by different network devices. If the source PSCell and target PSCell are associated with the same cell group or network device, the terminal device 120 may determine that the source PSCell and target PSCell were provided by the same network device.

[0076] Continuing to refer to Figure 2, if the source PSCell and target PSCell are provided by different network devices, the terminal device 120 may execute the first set of procedures (233). If the source PSCell and target PSCell are provided by the same network device, the terminal device 120 may execute the second set of procedures (234).

[0077] In some embodiments, the second set of procedures may include performing PDCP recovery for DRBs, for example, for all DRBs. In some embodiments, the second set of procedures may include performing PDCP Service Data Unit (SDU) destruction for SRBs, for example, for all SRBs. In some embodiments, the second set of procedures may include performing RLC re-establishment for DRBs and SRBs, for example, for all DRBs and all SRBs. In some embodiments, the second set of procedures may include maintaining (i.e., not updating) the security key associated with the target PSCell. It should be understood that the second set of procedures may include any appropriate combination of the above procedures.

[0078] In some scenarios, the SCG may be released. Conventionally, if the SCG is released, the UE may release conditional resets for conditional cell changes or additions. However, if conditional resets supporting selective activation of cell groups are released, the UE may not be able to perform subsequent CPAs without new RRC resets. In view of this, embodiments of the present disclosure further provide solutions for these scenarios.

[0079] Continuing to refer to Figure 2, terminal device 120 may decide that SCG release is to be performed (240). Next, terminal device 120 may execute a set of procedures (for convenience, also referred to here as the third set of procedures) (250).

[0080] In some embodiments, the third set of procedures may include maintaining stored information for conditional resets. In some embodiments, the third set of procedures may include maintaining stored information for conditional resets that support selective activation of cell groups. In some embodiments, maintaining stored information for conditional resets that support selective activation of cell groups includes at least one of the following: removing entries in the settings for conditional cell changes initiated by SN (e.g., SCG VarConditionlReconfig); maintaining (i.e., not releasing) stored settings for conditional resets initiated by MN that support selective activation of cell groups (e.g., MCG VarConditionlReconfig); or maintaining (i.e., not releasing) stored settings for conditional resets initiated by MN that support subsequent conditional cell additions (e.g., MCG VarConditionlReconfig).

[0081] In some embodiments, the third set of procedures may include continuing to perform conditional reset evaluations for subsequent conditional cell additions. In some embodiments, the third set of procedures may include pausing conditional reset evaluations for subsequent conditional cell changes. It should be understood that the third set of procedures may include any suitable combination of the above procedures. Thus, subsequent CPAs after SCG release can be supported.

[0082] When a cell modification or addition is performed on a PSCell, the terminal device may initiate a Random Access (RA) procedure on the target PSCell. Traditionally, once the RA procedure is complete, the terminal device's MAC entity may discard the explicitly signaled Contention-Free Random Access (CFRA) resources for any two-step and four-step RA types. However, this may render the CFRA resources unavailable for subsequent CPAs and CPCs.

[0083] In view of this, embodiments of the present disclosure provide a solution for the selective activation of cell groups. In this solution, once the RA procedure for the selective activation procedure of a cell group is completed, the terminal device 120 may retain (i.e., not discard) the CFRA resources for the corresponding two-step RA and four-step RA.

[0084] Up to this point, the UE behavior regarding the selective activation of cell groups has been clarified. Example implementation of network behavior for selective activation of cell groups

[0085] Traditionally, the MN releases the UE context by sending an SN release request message to the SN, meaning both the UE connection and conditional reset (and all other UE contexts) are released. However, in the case of selective activation of cell groups, the SN may only need to release the UE connection and maintain the conditional reset for the selective activation of the cell group. Therefore, it is unclear how to indicate the release of the UE connection and the release of the conditional reset separately.

[0086] Embodiments of this disclosure provide a solution for selective activation of cell groups to solve the above and other potential problems. For convenience, this solution is described below with reference to Figure 3.

[0087] Figure 3 is a schematic diagram showing another exemplary communication process 300 according to an embodiment of the present disclosure. For illustrative purposes, process 300 will be described with reference to Figure 1A. Process 300 may involve a terminal device 120 and network devices 110 and 130 as shown in Figure 1A. In this example, network device 110 is an MN (hereinafter referred to as MN 110 for convenience) that provides services to terminal device 120, network device 130 is a source SN (hereinafter referred to as SN 130 for convenience) that provides services to terminal device 120, and terminal device 120 is located in cell 131 (i.e., source PSCell).

[0088] As shown in Figure 3, the terminal device 120 may send a message to the MN 110 indicating that a conditional cell change is being performed from a source PSCell (e.g., cell 131) to a target PSCell (e.g., cell 143) (310). In some embodiments, the conditional cell change may be a subsequent conditional cell change. For example, if a CPC is triggered, the terminal device 120 may send an RRCReconfigurationComplete message to the MN 110, which includes an RRCReconfigurationComplete message for the selected candidate cell.

[0089] MN 110 may send an instruction to SN 130, which provides the source PSCell, indicating the release of the connection with terminal device 120 (320). Alternatively, MN 110 may send an instruction to SN 130 indicating the deactivation or suspension of the cell group. Alternatively, MN 110 may send an instruction to SN 130 indicating the withdrawal of terminal device 120.

[0090] In some embodiments, MN 110 may transmit the instruction via an Xn message. In some embodiments, the Xn message may be a newly defined message. In some embodiments, the Xn message may be an existing message, such as an SN release request message. In some embodiments, the SN release request message may include an IE indicating the release of the connection with terminal device 120, the deactivation or suspension of the cell group, or the departure of terminal device 120. It should be understood that any other suitable method is also possible.

[0091] Continuing to refer to Figure 3, upon receiving the instruction, SN 130 may release the connection with terminal device 120 while maintaining the UE context (i.e., maintaining the conditional reconfiguration that supports the selective activation of the cell group for the UE) (330). SN 130 may send an acknowledgment (ACK) to MN 110 for releasing the connection with terminal device 120 (340). Alternatively, SN 130 may send an ACK for deactivating or suspending the cell group. Alternatively, SN 130 may send an ACK for withdrawing from terminal device 120.

[0092] In some embodiments, the ACK may be sent within the Xn message. In some embodiments, the Xn message may be a newly defined message. In some embodiments, the Xn message may be an existing message, such as an SN release request acknowledgment message. It should be understood that any other suitable method is also possible.

[0093] Thus, the release of the UE connection may be indicated separately from the release of the conditional reset.

[0094] Figure 4 is a schematic diagram showing yet another exemplary communication process 400 according to an embodiment of the present disclosure. For illustrative purposes, process 400 will be described with reference to Figure 1A. Process 400 may involve network devices 110 and 130, 140, or 150 as shown in Figure 1A. In this example, network device 110 is an MN (hereinafter referred to as MN 110 for convenience) that provides services to terminal device 120, and network devices 130, 140, and 150 are SNs that provide candidate cells. For convenience, only network device 130 is shown as an example.

[0095] As shown in Figure 4, MN 110 may decide that the conditional setting for subsequent conditional cell addition or modification (i.e., selective activation of cell groups) is released (410). In some embodiments, SN (e.g., SN 130, 140, or 150) may decide to release the setting for subsequent conditional cell addition or modification and notify MN 120 of that decision.

[0096] Referring to Figure 4, MN 110 may send an instruction to SN 130, 140, or 150, which provides candidate cells for subsequent conditional cell additions or modifications, indicating the release of the setting for subsequent conditional cell additions or modifications (420).

[0097] In some embodiments, MN 110 may transmit the instruction via an Xn message. In some embodiments, the Xn message may be a newly defined message. In some embodiments, the Xn message may be an existing message, such as an SN release request message. In some embodiments, the SN release message may include an IE indicating the cancellation or release of a setting for selective activation of a cell group. It should be understood that any other suitable method is also possible.

[0098] Continuing to refer to Figure 4, SN 130, 140, or 150 may release the setting for subsequent conditional cell addition or modification (430). SN 130, 140, or 150 may send an ACK to MN 110 for releasing the setting for subsequent conditional cell addition or modification (440). In some embodiments, the ACK may be sent within an Xn message. In some embodiments, the Xn message may be a newly defined message. In some embodiments, the Xn message may be an existing message, such as an SN release request acknowledgment message. It should be understood that any other suitable method is also possible.

[0099] Thus, the release of a conditional reset may be indicated separately from the release of the UE connection.

[0100] Furthermore, the operations in processes 200, 300, and 400 may be carried out separately or in any appropriate combination. Implementation example of the method

[0101] Therefore, embodiments of this disclosure provide communication methods implemented in terminal devices and network devices. These methods are described below with reference to Figures 5-7.

[0102] Figure 5 shows exemplary communication methods 500 implemented in a terminal device according to some embodiments of the present disclosure. For example, method 500 may be implemented in a terminal device 120 as shown in Figure 1A. Method 500 will now be described with reference to Figure 1A for illustrative purposes. It should be understood that method 500 may include additional blocks not shown and / or some of the illustrated blocks may be omitted, and the scope of the present disclosure is not limited in this respect.

[0103] In block 510, the terminal device 120 determines that the subsequent conditional cell change will be executed from the source cell to the target cell.

[0104] In block 520, the terminal device 120 executes a first set of procedures during a subsequent conditional cell change. This first set of procedures includes at least one of the following: updating the security key associated with the target cell; performing PDCP re-establishment for the DRB and SRB; or performing RLC re-establishment for the DRB and SRB.

[0105] In some embodiments, the terminal device 120 may determine the cell identity and network device identity length information of the source cell and target cell, and determine whether the source cell and target cell were provided by different network devices based on the cell identity and network device identity length information of the source cell and target cell.

[0106] In some embodiments, the terminal device 120 may determine a first identity of the network device providing the source cell based on the cell identity and network device identity length information of the source cell, and determine a second identity of the network device providing the target cell based on the cell identity and network device identity length information of the target cell. If the first identity is the same as the second identity, the terminal device 120 may determine that the source cell and target cell were provided by the same network device. If the first identity is different from the second identity, the terminal device 120 may determine that the source cell and target cell were provided by different network devices.

[0107] In some embodiments, the terminal device 120 may determine information associated with a set of candidate cells for a subsequent conditional cell change, and based on the information associated with the set of candidate cells, determine whether the source cell and target cell were provided by different network devices. In some embodiments, the information associated with the set of candidate cells may include at least one of the following: the identity of the cell group associated with the candidate cell in the set of candidate cells, the identity of the network device associated with the candidate cell, or the identity of the secondary node associated with the candidate cell.

[0108] In some embodiments, if the source cell and target cell are provided by different network devices, the terminal device 120 may perform a first set of procedures. In some embodiments, the terminal device 120 may determine that the source cell and target cell are provided by the same network device based on information regarding the cell identity and network device identity length of the source cell and target cell. In these embodiments, the terminal device 120 may perform a second set of procedures, which includes at least one of the following: performing PDCP recovery for the DRB, performing PDCP Service Data Unit (SDU) destruction for the SRB, performing RLC re-establishment for the DRB and SRB, or maintaining the security key associated with the target cell.

[0109] In some embodiments, the terminal device 120 may decide that an SCG release is performed. In these embodiments, the terminal device 120 may execute a third set of procedures, which include at least one of the following: maintaining the stored information of the conditional reset, continuing to perform evaluations for subsequent conditional cell additions, or pausing evaluations for subsequent conditional cell changes.

[0110] In some embodiments, the terminal device 120 may maintain stored information for conditional resets by removing entries in the settings for subsequent conditional cell changes initiated by SN, maintaining stored settings for subsequent conditional cell changes initiated by MN, or maintaining stored settings for subsequent conditional cell additions initiated by MN.

[0111] In some embodiments, the terminal device 120 may execute an RA procedure for subsequent conditional cell modification or addition. Once the RA procedure is complete, the terminal device 120 may maintain the CFRA resource.

[0112] Method 500 can clarify UE behavior that effectively supports the selective activation of cell groups.

[0113] Figure 6 shows an exemplary communication method 600 implemented in a network device according to some embodiments of the present disclosure. For example, method 600 may be implemented in a network device 110 as shown in Figure 1A. Method 600 will now be described with reference to Figure 1A for illustrative purposes. It should be understood that method 600 may include additional blocks not shown and / or some of the illustrated blocks may be omitted, and the scope of the present disclosure is not limited in this respect.

[0114] In block 610, the first network device (e.g., network device 110) receives a message from a terminal device (e.g., terminal device 120) indicating that a conditional cell change is to be performed from a source cell (e.g., cell 131) to a target cell (e.g., cell 143).

[0115] In block 620, network device 110 sends an instruction to a second network device (e.g., network device 130) that provides the source cell, indicating the release of the connection with terminal device 120. Thus, the second network device may release the connection with terminal device 120 and maintain the settings for selective activation of the cell group. It should be understood that this instruction may be sent in any appropriate manner.

[0116] In some embodiments, the network device 110 may receive an ACK from the network device 130 regarding the release of the connection with the terminal device 120. It should be understood that such ACK may be transmitted in any appropriate manner.

[0117] Method 600 can clarify the network behavior necessary to adequately support subsequent CPCs.

[0118] Figure 7 shows another exemplary communication method 700 implemented in a network device according to some embodiments of the present disclosure. For example, method 700 may be implemented in a network device 110 as shown in Figure 1A. Method 700 will now be described with reference to Figure 1A for illustrative purposes. It should be understood that method 700 may include additional blocks not shown and / or some of the illustrated blocks may be omitted, and the scope of the present disclosure is not limited in this respect.

[0119] In block 710, the first network device (for example, network device 110) determines that the settings for subsequent conditional cell additions or modifications are released.

[0120] In block 720, network device 110 sends an instruction to a second network device (e.g., network devices 130, 140, or 150) that provides candidate cells for subsequent conditional cell additions or modifications, indicating the release of the setting for subsequent conditional cell additions or modifications. It should be understood that such instructions may be sent in any appropriate manner.

[0121] In some embodiments, network device 110 may receive an ACK from a second network device (e.g., network devices 130, 140, or 150) for the cancellation of the setting for subsequent conditional cell addition or modification. It should be understood that such ACK may be transmitted in any appropriate manner.

[0122] Method 700 can clarify the network behavior necessary to effectively support subsequent CPAs.

[0123] Since the operations of methods 500, 600, and 700 are the same as those described in relation to Figures 2 to 4, for the sake of brevity, we will omit the redundant explanation of other details here. Examples of device and equipment implementation

[0124] Figure 8 is a schematic block diagram of a device 800 suitable for implementing an embodiment of the present disclosure. The device 800 may be considered as another exemplary embodiment of the terminal device 120 or network devices 110, 130, or 140 as shown in Figure 1A. Thus, the device 800 may be implemented in or as part of the terminal device 120 or network devices 110, 130, or 140.

[0125] As shown in the figure, the device 800 comprises a processor 810, a memory 820 coupled to the processor 810, appropriate transmitters (TX) and receivers (RX) 840 coupled to the processor 810, and a communication interface coupled to the TX / RX 840. 820 is, and stores at least a portion of program 830. The TX / RX 840 is used for bidirectional communication. The TX / RX 840 has at least one antenna to facilitate communication, but the access nodes referred to herein may actually 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 a Mobility Management Entity (MME) / Access and Mobility Management Function (AMF) / SGW / UPF and an eNB / gNB, the Un interface for communication between an eNB / gNB and a Relay Node (RN), or the Uu interface for communication between an eNB / gNB and a terminal device.

[0126] It is assumed that program 830 includes program instructions that, when executed by the associated processor 810, enable the device 800 to operate according to embodiments of the present disclosure, as described herein with reference to Figures 2 to 7. Embodiments of the present specification may be implemented by computer software executable by the processor 810 of the device 800, by hardware, or by a combination of software and hardware. The processor 810 may be configured to implement various embodiments of the present disclosure. Furthermore, a combination of the processor 810 and memory 820 may form a processing means 850 suitable for implementing various embodiments of the present disclosure.

[0127] Memory 820 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 820 is shown in device 800, there may be several physically different memory modules in device 800. Processor 810 may be of any type suitable for a local technology network and may include, as non-limiting examples, one or more of general-purpose computers, dedicated computers, microprocessors, digital signal processors (DSPs), and processors based on multi-core processor architectures. Device 800 may have multiple processors, for example, application-specific integrated circuit chips that are time-dependent to a clock that synchronizes the main processor.

[0128] In some embodiments, the terminal device comprises a circuit configured to determine that a subsequent conditional cell change is performed from a source cell to a target cell and to execute a first set of procedures including at least one of the following: updating the security key associated with the target cell; performing PDCP re-establishment for the DRB and SRB; or performing RLC re-establishment for the DRB and SRB.

[0129] In some embodiments, the first network device comprises a circuit configured to receive a message from a terminal device indicating that a conditional cell change is performed from a source cell to a target cell, and to send an instruction to a second network device providing the source cell indicating the release of the connection with the terminal device.

[0130] In some embodiments, the first network device comprises a circuit which determines that a setting for a subsequent conditional cell addition or modification is to be released and is configured to transmit an instruction indicating the release of the setting for the subsequent conditional cell addition or modification to a second network device which provides candidate cells for the subsequent conditional cell addition or modification.

[0131] As used herein, the term “circuit” may mean 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. In yet another example, a circuit may be any part of a hardware processor having a digital signal processor, software and one or more memories, which work together to cause a device such as a terminal or network device to perform various functions. In yet another example, a circuit may be a hardware circuit and / or a processor such as a microprocessor or a part thereof that requires software / firmware for operation, but the software may not be present if it is not required for operation. As used herein, the term “circuit” also includes the implementation of a hardware circuit or one or more processors alone, or a part of a hardware circuit or one or more processors and their (or their) accompanying software and / or firmware.

[0132] Overall, various embodiments of the 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 Disclosure are illustrated and described using block diagrams, flowcharts, or any other pictorial representation, it should be understood that any blocks, devices, 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.

[0133] This disclosure also provides at least one computer program product tangibly stored on a non-temporary computer-readable storage medium. The computer program product includes computer-executable instructions, such as instructions contained in a program module, which are executed within a device on a target real or virtual processor to perform the processes or methods described above with reference to Figures 2-7. Generally, a program module includes routines, programs, libraries, objects, classes, components, data structures, etc., that perform a specific task or realize a specific abstract data type. In various embodiments, the functions of program modules may be combined or separated among program modules as needed. The machine-executable instructions of a program module may be executed within a local or distributed device. In a distributed device, program modules may reside in both local and remote storage media.

[0134] Program code for performing the methods of this disclosure may be written in any combination of one or more programming languages. These program codes may be provided to a processor or controller of a general-purpose computer, a dedicated computer, or other programmable data processing device, and when executed by the processor or controller, the program code may implement the functions / operations specified in the flowcharts and / or block diagrams. The program code may run entirely on a machine, partially on a machine, as an independent software package, partially on a machine and partially on a remote machine, or entirely on a remote machine or server.

[0135] The program code described above may be implemented on a machine-readable medium, which may be any tangible medium that can contain or store programs used by or associated with an instruction execution system, device, or apparatus. 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, devices, or apparatus, or any suitable combination of the aforementioned mediums. More specific examples of machine-readable storage media may include electrical connections with one or more wires, portable computer disks, 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 suitable combination of the above.

[0136] While the operations have been described in a specific order, it should not be understood that, in order to obtain the desired results, these operations must be performed in the specific order shown, or in a sequential order, or that all of the described operations must be performed. In some cases, multitasking and parallel processing may be advantageous. Similarly, while some specific implementation details are included in the above discussion, 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. Some features described in the context of individual embodiments may 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 suitable subcombination.

[0137] 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 of implementing the claims.

Claims

1. User equipment (UE) A means for receiving from the network a conditional reset for a subsequent conditional PSCell addition or modification, which indicates that the configuration of one or more candidate PSCells for the said subsequent conditional PSCell addition or modification is supported. Means for receiving from the network information used to determine whether the UE should perform a security update when the conditional reset is performed, information identifying a first cell set associated with one or more candidate PSCells, If the first cell set is different from the second cell set associated with the serving PSCell, means for performing the security update, including a security key update associated with the secondary key, A UE equipped with [unclear].

2. Means for performing the subsequent conditional PSCell addition or modification The UE according to claim 1, further comprising:

3. Means for performing Packet Data Convergence Protocol (PDCP) re-establishment for Data Radio Bearers (DRBs) and Signaling Radio Bearers (SRBs) if the first cell set is different from the second cell set associated with the Serving PSCell. The UE according to claim 1 or 2, further comprising:

4. Means for performing radio link control (RLC) re-establishment for a data radio bearer (DRB) and a signaling radio bearer (SRB) if the first cell set is different from the second cell set associated with the serving PSCell. The UE according to claim 1 or 2, further comprising:

5. Means for performing Packet Data Convergence Protocol (PDCP) recovery for a Data Radio Bearer (DRB) when the first cell set is the same as the second cell set associated with the Serving PSCell. The UE according to claim 1 or 2, further comprising:

6. Means for performing Packet Data Convergence Protocol (PDCP) Service Data Unit (SDU) discarding with respect to a Signaling Radio Bearer (SRB) if the first cell set is the same as the second cell set associated with the Serving PSCell. The UE according to claim 1 or 2, further comprising:

7. Means for releasing a Secondary Cell Group (SCG), Means for maintaining the conditional reset associated with the Master Cell Group (MCG), Means for evaluating the execution conditions of one or more candidate PSCells, The UE according to claim 1 or 2, further comprising:

8. The aforementioned UE is configured to receive the conditional reconfiguration from the master node (MN). The UE according to claim 7.

9. A means for sending an RRC reconfiguration completion message, including a message indicating that the Radio Resource Control (RRC) reconfiguration for the selected candidate PScell, to the Master Node (MN). The UE according to claim 1 or 2, further comprising:

10. The aforementioned MN is configured to notify the secondary node (SN) that the aforementioned UE has already been moved to another SN. The UE as described in claim 9.

11. A method for user equipment (UE), Receiving a conditional reset from the network for a subsequent conditional PSCell addition or modification, which indicates that the configuration of one or more candidate PSCells for the said subsequent conditional PSCell addition or modification is supported, Information used to determine whether the UE should perform a security update when the conditional reset is performed, including receiving from the network information that identifies a first cell set associated with one or more candidate PSCells, If the first cell set is different from the second cell set associated with the serving PSCell, the security update, including a security key update associated with the secondary key, is performed. A method that includes this.

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