User Equipment, Radio Access Network Node, and Methods Thereof

Abstract

The embodiments of the present disclosure relate to a communication method, an apparatus, and a computer-readable medium. A terminal device receives a conditional reconfiguration for a set of candidate cells from a first network device, the conditional reconfiguration including information indicating that a subsequent conditional cell change is enabled for at least one candidate cell in the set of candidate cells. If a cell change or addition is performed based on the conditional reconfiguration, the terminal device maintains at least a portion of the conditional reconfiguration for use in the subsequent conditional cell change. In this way, a procedure for a subsequent conditional cell change can be enabled.

Description

[Technical field]

[0001] FIELD OF THE DISCLOSURE 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 conditional cell changes. [Background technology]

[0002] In the case of conditional primary secondary cell (PSCell) change (CPC) / conditional PSCell addition (CPA) in 3GPP (third generation partnership project) Release 17, a terminal device with a CPC / CPA configured must release the CPC / CPA configuration when completing random access to a target PSCell. Thus, the terminal device has no opportunity to perform subsequent CPC / CPA without prior CPC / CPA reconfiguration and reinitialization from the network side. This increases cell change delay and signaling overhead, especially when frequent secondary cell group (SCG) changes occur when operating in frequency range 2 (FR2). Therefore, multi-random access technology dual connectivity with selective activation of cell groups (MR-DC) aims to enable subsequent CPC / CPA after SCG change without reconfiguration and reinitialization during CPC / CPA preparation from the network side, thereby reducing the signaling overhead and interruption time for SCG change. However, the mechanism and procedure of subsequent CPC is still incomplete and needs to be further studied. Summary of the Invention [Problem to be solved by the invention]

[0003] In general, the exemplary embodiments of the present disclosure provide a communication method, apparatus, and computer storage medium for subsequent conditional cell changes. [Means for solving the problem]

[0004] In a first aspect, a method of communication is provided, the method comprising: receiving, at a terminal device, a conditional reconfiguration from a first network device for a set of candidate cells, the conditional reconfiguration including information indicating that a subsequent conditional cell change has been enabled for at least one candidate cell in the set of candidate cells, and, pursuant to a determination that a cell change or addition has been performed, retaining at least a portion of the conditional reconfiguration for use in the subsequent conditional cell change.

[0005] In a second aspect, a method of communication is provided, the method including: transmitting, in a first network device, a conditional reconfiguration for a set of candidate cells to a terminal device, the conditional reconfiguration including information indicating that a subsequent conditional cell change has been enabled for at least one candidate cell in the set of candidate cells.

[0006] In a third aspect, a method of communication is provided, the method including: receiving, at a second network device, a request for resource allocation from a first network device, the request including information indicating that a subsequent conditional cell change has been enabled for at least one candidate cell in a set of candidate cells, and transmitting to the first network device an acknowledgement of the enablement of the subsequent conditional cell change and a data forwarding address associated with the second network device.

[0007] In a fourth aspect, a method of communication is provided, the method including: receiving, at a third network device, a message from a first network device including information indicating that a subsequent conditional cell change has been enabled for at least one candidate cell in a set of candidate cells; and transmitting an acknowledgement of the enablement of the subsequent conditional cell change to the first network device.

[0008] In a fifth aspect, a method of communication is provided, the method including: transmitting, at a third network device, a request for a conditional cell change to a first network device, the request including at least one of a data forwarding address associated with the third network device, or information indicating that a subsequent conditional cell change has been enabled for at least one candidate cell in a set of candidate cells.

[0009] In a sixth aspect, there is provided a terminal device, the terminal device comprising a processor configured to cause the terminal device to execute a method according to the first aspect of the present disclosure.

[0010] In a seventh aspect, there is provided a network device, comprising a processor configured to cause the network device to perform a method according to any one of the second to fifth aspects of the present disclosure.

[0011] In an eighth aspect, a computer readable medium is provided having instructions stored thereon that, when executed on at least one processor, cause the at least one processor to perform a method according to the first aspect of the present disclosure.

[0012] In a ninth aspect, there is provided a computer readable medium having stored thereon instructions which, when executed on at least one processor, cause the at least one processor to perform a method according to any one of the second to fifth aspects of the present disclosure.

[0013] Other features of the present disclosure will become readily apparent from the following description. [Brief description of the drawings]

[0014] The above and other objects, features and advantages of the present disclosure will become more apparent from the following detailed description of several embodiments of the present disclosure in the accompanying drawings. [Figure 1] FIG. 1 illustrates an example communication network in which some embodiments of the present disclosure may be implemented. [Diagram 2] FIG. 2 is a schematic diagram illustrating an exemplary process of CPA with a subsequent CPC according to an embodiment of the present disclosure. [Diagram 3] FIG. 2 is a schematic diagram illustrating an example process of a master node (MN)-initiated CPC having a subsequent CPC according to an embodiment of the present disclosure. [Figure 4] FIG. 2 is a schematic diagram illustrating an example process of a CPC initiated by a secondary node (SN) having a subsequent CPC according to an embodiment of the present disclosure. [Diagram 5] FIG. 1 is a schematic diagram illustrating an exemplary process of subsequent CPC, according to an embodiment of the present disclosure. [Figure 6] FIG. 2 illustrates an exemplary communication method implemented in a terminal device according to some embodiments of the present disclosure. [Figure 7] A diagram illustrating an example communication method implemented in a first network device in accordance with some embodiments of the present disclosure. [Figure 8] A diagram illustrating an example communication method implemented in a second network device in accordance with some embodiments of the present disclosure. [Figure 9] A diagram illustrating an example communication method implemented in a third network device in accordance with some embodiments of the present disclosure. [Figure 10] A diagram showing another exemplary communication method implemented in a third network device in accordance with some embodiments of the present disclosure. [Figure 11] FIG. 1 is a schematic block diagram of an apparatus suitable for implementing embodiments of the present disclosure.

[0015] In the drawings, the same or similar reference numbers represent the same or similar elements. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] The principles of the present disclosure will now be described with reference to some embodiments. It should be understood that these embodiments are provided for illustrative purposes only, to assist those skilled in the art in understanding and implementing the present disclosure, and do not imply any limitations on the scope of the present disclosure. The disclosure described herein can be implemented in various ways different from those described below.

[0017] In the following description and claims, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains.

[0018] 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 Low Latency Communication (URLLC) devices, Internet of Everything (IoE) devices, machine type communication (MTC) devices, vehicle-mounted devices for V2X communications where X means pedestrian, vehicle, or infrastructure / network, devices for integrated access and integrated access and backhaul (IAB), Small Data Transmission (SDT), Multicast and Broadcast Services (MBS), positioning, dynamic / flexible duplication in commercial networks, reduced capability (RedCap), High Altitude Platforms (HAP) including satellites and Unmanned Aircraft Systems (UAS). These include, but are not limited to, satellite-mounted vehicles or airborne vehicles in a non-terrestrial network (NTN) including the ICT Platform, extended reality (XR) devices including different types of reality such as augmented reality (AR), mixed reality (MR), and virtual reality (VR), unmanned aerial vehicles (UAVs), which are aircraft without a human pilot and are commonly referred to as drones, devices on high speed trains (HSTs), image acquisition devices such as digital cameras, sensor game devices, music storage and playback devices, or Internet appliances that enable wireless or wired Internet access and browsing.The "Terminal Equipment" 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, over-the-air software distribution, group communication and IoT applications. It may also incorporate one or more Subscriber Identity Modules (SIMs), known as multi-SIMs. The term "Terminal Equipment" may be used interchangeably with UE, mobile station, subscriber station, mobile terminal, user terminal, or wireless device.

[0019] The term "network device" refers to a device capable of providing or hosting a cell or coverage in which a terminal device can communicate. Examples of network devices include, but are not limited to, a Node B (NodeB or NB), an evolved Node B (eNodeB or eNB), a next generation Node B (gNB), a transmit / receive point (TRP), a remote radio unit (RRU), a radio head (RH), a remote radio head (RRH), an IAB node, a femto node, a pico node, a reconfigurable intelligent surface (RIS), a low power node such as a network controlled repeater, etc.

[0020] The terminal device or network device may have the capability of artificial intelligence (AI) or machine learning. Generally, it includes a model trained from a large amount of data collected for a specific function and can be used to predict some information.

[0021] The terminal device or network device may operate on several frequency ranges, such as FR1 (410 MHz-7125 MHz), FR2 (24.25 GHz-71 GHz), frequency bands greater than 100 GHz, and Tera Hertz (THz). It can also operate on licensed / unlicensed / shared spectrum. The terminal device may have two or more connections with the network device under Multi-Radio Dual Connectivity (MR-DC) application scenarios. The terminal device or network device can operate in full duplex, flexible duplex, and cross division duplex modes.

[0022] The network device may have a function of network energy saving, Self-Organizing Networks (SON) / Minimization of Drive Test (MDT). The terminal may have a function of power saving.

[0023] Embodiments of the present disclosure may be implemented in test equipment, such as, for example, a signal generator, a signal analyzer, a spectrum analyzer, a network analyzer, a test terminal equipment, a test network equipment, a channel emulator, and the like.

[0024] In one embodiment, the terminal device can connect to a first network device and a second network device. One of the first network device and the second network device may be a master node and the other may be a secondary node. The first network device and the second network device 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 may be transmitted from at least one of the first network device or the second network device to the terminal device. 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 to the terminal device directly or via the first network device. In one embodiment, information about 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 regarding the reconfiguration of the terminal device configured by the second network device may be transmitted from the second network device directly to the terminal device or via the first network device.

[0025] As used herein, the singular forms "a," "an," and "said" include the plural forms unless the context clearly indicates otherwise. The term "comprises" and variations thereof should be understood as open-ended terms meaning "including, but not limited to." The term "based on" should be understood as "based at least in part 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," and the like may refer to different or the same object. The following may include other explicit and implicit definitions.

[0026] In some instances, values, procedures, or devices are referred to as "best," "lowest," "highest," "minimum," "maximum," etc. It should be understood that such descriptions are intended to illustrate that selections can be made from among many functional alternatives used, and that such selections are not necessarily better, smaller, higher, or otherwise more preferred than other selections.

[0027] In this application, the term "cell change or addition" may be used interchangeably with "reconfigurationWithSync for SCG or Master Cell Group (MCG)." In the context of this application, the term "PCell" refers to an SpCell of an SCG, the term "PCell" refers to an SpCell of an MCG, and "SpCell" refers to a primary cell of an SCG or MCG.

[0028] As mentioned above, the mechanism and procedure of subsequent CPC are still incomplete and need to be further studied. In view of this, the embodiment of the present disclosure provides a solution for enabling subsequent conditional cell change. In this solution, the conditional reconfiguration includes information indicating that the subsequent conditional cell change is enabled for at least one candidate cell in a set of candidate cells, and when a cell change or addition is performed, at least a part of the conditional reconfiguration is maintained for the at least one candidate cell. In this way, the subsequent conditional cell change can be enabled efficiently and flexibly. Hereinafter, the principle and the embodiment of the present disclosure will be described in detail with reference to the accompanying drawings.

[0029] It should be understood that the present solution may be applied in SCG change or MCG change. That is, the present solution may also be applied to subsequent CPC or subsequent conditional handover. Subsequent CPC or subsequent conditional handover may be referred to as selective activation of cell group, selective activation of SCG, subsequent SCG change, subsequent cell group change, or subsequent conditional cell change. For convenience, the embodiment of the present disclosure will be described by taking subsequent CPC as an example.

[0030] Communication Network Example 1 is a schematic diagram of an exemplary communication environment 100 in which embodiments of the present disclosure may be implemented. As shown in FIG. 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 served by the network device 110.

[0031] The communication environment 100 may also include one or more other network devices, such as network devices 130, 140, and 150. The network device 130 provides cells 131, 132, and 133. The network device 140 provides cells 141, 142, and 143, and the network device 150 provides cells 151, 152, and 153. Note that the number of cells is not limited to three, and more or fewer cells may be configured for the terminal device 110.

[0032] Assume that the terminal device 120 is capable of establishing a dual connection (i.e., simultaneous connection) with two network devices. For example, the network device 110 may function as an MN (for convenience, also referred to as MN 110 hereinafter), and the network device 130 may function as an SN (for convenience, also referred to as SN 130 hereinafter). Although only cell 111 is shown, the MN 110 may provide multiple cells, which may form an MCG for the terminal device 120. Assume that the cell 111 is a primary cell (i.e., PCell) in the MCG. Furthermore, the cells 131, 132, and 133 provided by the network device 130 may form an SCG for the terminal device 120. Assume that the cell 131 is a primary cell (i.e., PSCell) in the SCG.

[0033] The communications environment 100 may also include a core network 160. The core network 160 may include a user port function (UPF) 161 and an access management function (AMF) 162. It should be understood that the core network 160 may include any other suitable elements.

[0034] The SN 130 may communicate with the terminal equipment 120 via a channel such as a wireless communication channel. Similarly, the MN 110 may also communicate with the terminal equipment 120 via a channel such as a wireless communication channel. The SN 130 may communicate with the MN 110 via a control plane interface such as Xn-C. The MN 110 may communicate with the core network 160, e.g., the AMF 162, via a control plane interface such as NG-C. The SN 130 may also communicate with the MN 110 via a user plane interface such as Xn-U and with the core network 160, e.g., the UPF 161, via a user plane interface such as NG-U.

[0035] It should be understood that the number of devices or cells in Figure 1 is given for illustrative purposes and does not imply any limitations to the present disclosure. Communications environment 100 may include any suitable number of network devices and / or terminal devices and / or cells suitable for implementing embodiments of the present disclosure.

[0036] Communications 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), Machine Type Communication (MTC), etc. Embodiments of the present disclosure may be performed according to any generation of communication protocols now known or 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.

[0037] In some embodiments, network device 110 may configure a conditional reconfiguration for terminal device 120 .

[0038] Assume that cells 131-133, 141-143, and 151-153 are set as candidate cells in the terminal device 110. In some scenarios, the terminal device 120 may initially communicate only with the network device 110. As the terminal device 120 moves, if the conditions for a candidate cell (e.g., cell 131) are met, the terminal device 120 may be allowed to establish a dual connection with the network device 110 and the network device 130. This process of SN addition may be referred to as CPA.

[0039] In some scenarios, the terminal device 120 may establish a dual connection with the network devices 110 and 130. The network device 110 functions as an MN, and the network device 130 functions as an SN. When the terminal device 120 moves, if a condition for another candidate cell (e.g., cell 142) is met, the SN serving the terminal device 120 may be changed from the network device 130 (also referred to as source SN or current SN 130) to the network device 140 (also referred to as target SN 140). This process of PScell ​​change may be referred to as CPC. In some scenarios, after the terminal device is configured with conditional reconfiguration and subsequent CPC is enabled, but before at least one execution condition is met for any candidate PScell, the terminal device 120 may receive an RRC reconfiguration message including reconfigurationWithSync from the network device 110 and perform a PScell ​​change or addition accordingly. This procedure is referred to as a conventional PScell ​​change or addition. As an example, after a conventional PSCell change or addition procedure, the SN serving the terminal device 120 is the network device 140.

[0040] After the above CPA, CPC, or conventional PSCell change / add procedure, when the terminal device 120 moves further, if the condition for yet another candidate cell (e.g., cell 152) is met, the SN serving the terminal device 120 may be changed from the network device 140 to the network device 150 (also referred to as target SN 150). This SN change process may be referred to as subsequent CPC.

[0041] The embodiments of the present disclosure provide a solution for enabling and executing subsequent conditional cell changes, such as conditional PSCell or PCell changes.

[0042] Example of implementing subsequent conditional cell changes In this solution, the conditional reconfiguration includes information indicating that a subsequent conditional cell change is enabled for at least one candidate cell in a set of candidate cells. When a cell change or addition is performed, at least a part of the conditional reconfiguration is maintained for the at least one candidate cell. In this way, the subsequent conditional cell change can be flexibly enabled. For convenience, the following takes the subsequent CPC as an example for a more detailed description.

[0043] 1. Example of CPA with subsequent CPC 2 is a schematic diagram illustrating an example process 200 of CPA with a subsequent CPC according to an embodiment of the present disclosure. For illustrative purposes, the process 200 is described with reference to FIG. 1. The process 200 may involve the terminal device 120, the network devices 110, 140 and 150, the UPF 161 and the AMF 162 as shown in FIG. 1. In this example, the network device 110 is a MN serving the terminal device 110, and the network devices 140 and 150 are potential target SNs serving the terminal device 110.

[0044] 2, the MN 110 may send a request for resource allocation to the target SN 140 (201). The MN 110 may also send the request for resource allocation to the target SN 150 (201'). For example, the MN 110 may decide to configure a CPA and subsequent CPC activation for the terminal device 110. In this case, the MN 110 may send a request for resource allocation.

[0045] In some embodiments, the request may be a SN Addition Request message. Of course, any other suitable message is also possible. In some embodiments, the request may include information indicating that the subsequent CPC has been enabled for at least one candidate cell. For example, the request may include at least one of an indication indicating that the subsequent CPC has been enabled or a list of candidate PSCells indicating the at least one candidate cell for which the subsequent CPC has been enabled. Thus, the enablement of the subsequent CPC may be applied to all cells in the list of candidate PSCells or may be applied to a subset of cells in the list of candidate PSCells.

[0046] It should be understood that the request may further include any other suitable information. For example, the request may include another list of candidate PSCells indicating all candidate PSCells for the terminal device 120.

[0047] 2, target SN 140 may send an acknowledgment for the request to MN 110 (202). The acknowledgment for the request may include an acknowledgment for the subsequent CPC activation and a data forwarding address associated with target SN 140. Similarly, target SN 150 may send an acknowledgment for the request to MN 110 (202'). The acknowledgment for the request may include an acknowledgment for the subsequent CPC activation and a data forwarding address associated with target SN 150.

[0048] The MN 110 may send (203) a data forwarding address to the target SN 140 and may also send (203') a data forwarding address to the target SN 150. In some embodiments, the data forwarding address may include a data forwarding address associated with the MN 110. Thus, the MN 110 provides indirect data forwarding between target SNs. In some embodiments, the data forwarding address may include a data forwarding address associated with one or more other target SNs. For example, the MN 110 may send (203) a data forwarding address associated with the target SN 150 to the target SN 140 and may also send (203') a data forwarding address associated with the target SN 150 to the target SN 140. Thus, direct data forwarding between target SNs may be used.

[0049] 2, the MN 110 may send a conditional reconfiguration for the set of candidate cells to the terminal device 120 (204). For example, the MN 110 may send an RRCReconfiguration message including the conditional reconfiguration to the terminal device 120. Of course, any other suitable message is also possible.

[0050] In some embodiments, the conditional reconfiguration may include information indicating that a subsequent CPC has been enabled for at least one candidate cell in the set of candidate cells. That is, the information indicating the enablement of the subsequent CPC may apply to all conditional reconfiguration entries (i.e., all candidate PSCells). Alternatively, the information indicating the enablement of the subsequent CPC may apply only to a portion of the conditional reconfiguration entries (i.e., a portion of the candidate PSCells). For example, a list of conditional reconfiguration IDs (CondReconfigIds) supporting the subsequent CPC may be provided. As another example, the enablement of the subsequent CPC may be configured for the conditional reconfiguration entry.

[0051] It should be understood that the conditional reconfiguration may include any other suitable information, for example, the conditional reconfiguration may further include an execution condition for the CPA / CPC evaluation associated with each candidate cell.

[0052] Upon receiving the conditional reconfiguration, the terminal device 120 may transmit an RRC reconfiguration complete message to the MN 110 (205). For example, the terminal device 120 may apply the RRC configuration except for the CPA / CPC configuration, store the CPA / CPC configuration, and return the RRC reconfiguration complete message to the MN 110.

[0053] The terminal device 120 may start evaluating the execution conditions for the set of candidate cells. In some embodiments, the terminal device 120 may detect that the execution conditions for a candidate cell (also referred to herein as a selected candidate cell) are met (206). In this case, the terminal device 120 may perform a cell addition, i.e., a CPA. In some embodiments, the terminal device 120 may receive an RRCReconfiguration message including reconfigurationWithSync before the execution conditions for any candidate cell are met (206'). In this case, the terminal device 120 may also perform a cell addition, i.e., a conventional PSCell addition.

[0054] For cell addition (CPA or conventional PSCell addition), the terminal device 120 may apply an RRC reconfiguration message corresponding to the target SN 140 and send (207) an MN RRC reconfiguration complete message to the MN 110. The MN RRC reconfiguration complete message includes an SN RRC reconfiguration complete message for the target SN 140 and information of the selected candidate cell (e.g., a conditional reconfiguration ID).

[0055] After the cell addition, the terminal device 120 does not delete (i.e., maintains) the stored CPA / CPC configuration and associated measurement configuration, and continues to evaluate the execution conditions for the candidate cell. In some embodiments, the terminal device 120 may maintain all entries in the stored CPA / CPC configuration. In some embodiments, the terminal device 120 may delete entries of conditional reconfiguration and associated measurement configuration where the subsequent CPC is not enabled (i.e., disabled), and maintain entries of conditional reconfiguration and associated measurement reconfiguration where the subsequent CPC is enabled. In this way, subsequent CPC is facilitated.

[0056] Upon receiving the MN RRC Reconfiguration Complete message, the MN 110 may send 208 an SN RRC Reconfiguration Complete message contained in the MN RRC Reconfiguration Complete message to the selected candidate cell (in this example, the target SN 140).

[0057] The terminal device 120 may then perform 209 synchronization to the selected candidate cell (i.e., target SN 140). The MN 110 may perform 210 SN status transition to the target SN 140. Data transfer 211 may be performed from the MN to the target SN 140. User plane (UP) path update 222 to the core network may be performed via a protocol data unit (PDU) session path update procedure. One or more subsequent CPCs 213 may then be performed. Details of the subsequent CPCs are described below with reference to FIG. 5.

[0058] 2. Implementation of MN-initiated CPC with subsequent CPC 3 is a schematic diagram illustrating an example process 300 of MN-initiated CPC with subsequent CPC according to an embodiment of the present disclosure. For illustrative purposes, the process 300 is described with reference to FIG. 1. The process 300 may involve terminal device 120, network devices 110, 130, 140 and 150, UPF 161 and AMF 162 as shown in FIG. 1. In this example, network device 110 is a MN serving terminal device 110, network device 130 is a source SN serving terminal device 110, and network devices 140 and 150 are potential target SNs serving terminal device 110.

[0059] 3, the MN 110 may send a request for resource allocation to the target SN 140 (301). The MN 110 may also send the request for resource allocation to the target SN 150 (301'). For example, the MN 110 may decide to configure a CPC and subsequent CPC activation for the terminal device 110. In this case, the MN 110 may send the request for resource allocation.

[0060] In some embodiments, the request may be a SN Addition Request message. Of course, any other suitable message is also possible. In some embodiments, the request may include information indicating that the subsequent CPC has been enabled for at least one candidate cell. For example, the request may include at least one of an indication indicating that the subsequent CPC has been enabled or a list of candidate PSCells indicating the at least one candidate cell for which the subsequent CPC has been enabled. Thus, the enablement of the subsequent CPC may be applied to all cells in the list of candidate PSCells or may be applied to a subset of cells in the list of candidate PSCells.

[0061] It should be understood that the request may further include any other suitable information. For example, the request may include another list of candidate PSCells indicating all candidate PSCells for the terminal device 120.

[0062] The MN 110 may send 302 a message to the source SN 130 including information indicating that a subsequent CPC has been enabled for at least one candidate cell. In some embodiments, this message may be an SN modification request message or any other suitable Xn message. In some embodiments, this information may indicate the enablement of the subsequent CPC and a list of candidate PSCells for which the subsequent CPC has been enabled.

[0063] 3, target SN 140 may send an acknowledgment for the request to MN 110 (303). The acknowledgment for the request may include an acknowledgment for the subsequent CPC activation and a data forwarding address associated with target SN 140. Similarly, target SN 150 may send an acknowledgment for the request to MN 110 (303'). The acknowledgment for the request may include an acknowledgment for the subsequent CPC activation and a data forwarding address associated with target SN 150.

[0064] The source SN 130 may send an acknowledgement of the subsequent CPC activation to the MN 110 (304). In some embodiments, the source SN 130 may send an Xn message as an acknowledgement of the subsequent CPC activation. For example, the Xn message may be an SN modification request acknowledgement message or any other suitable Xn message. In some embodiments, the Xn message may include at least one of a set of SCG radio configurations corresponding to candidate PSCells of the source SN 130 in the RRC reconfiguration and a data forwarding address associated with the source SN 130.

[0065] The MN 110 may send (305) a data forwarding address to the target SN 140 and may also send (305') a data forwarding address to the target SN 150. In some embodiments, the data forwarding address may include a data forwarding address associated with the MN 110. Thus, the MN 110 provides indirect data forwarding between the source SN and the target SN. In some embodiments, the data forwarding address may include a data forwarding address associated with one or more other target SNs. For example, the MN 110 may send (305') a data forwarding address associated with the target SN 150 to the target SN 140 and may also send (305') a data forwarding address associated with the target SN 140 to the target SN 150. In some embodiments, the data forwarding address may include a data forwarding address associated with the source SN 130. For example, the MN 110 may send (305') a data forwarding address associated with the source SN 130 to the target SN 140 and to the target SN 150. Thus, direct data forwarding may be enabled.

[0066] The MN 110 may send 306 a data forwarding address to the source SN 130. In some embodiments, the data forwarding address may include a data forwarding address associated with the MN 110, thus providing indirect data forwarding between the source SN and the target SN. In some embodiments, the data forwarding address may include a data forwarding address associated with the target SNs 140 and 150, thus enabling direct data forwarding.

[0067] 3, the MN 110 may transmit (307) a conditional reconfiguration for the set of candidate cells to the terminal device 120. For example, the MN 110 may transmit an RRCReconfiguration message including the conditional reconfiguration to the terminal device 120. Of course, any other suitable message is also possible.

[0068] In some embodiments, the conditional reconfiguration may include information indicating that a subsequent CPC has been enabled for at least one candidate cell in the set of candidate cells. That is, the information indicating the enablement of the subsequent CPC may apply to all conditional reconfiguration entries (i.e., all candidate PSCells). Alternatively, the information indicating the enablement of the subsequent CPC may apply only to a portion of the conditional reconfiguration entries (i.e., a portion of the candidate PSCells). For example, a list of conditional reconfiguration IDs (CondReconfigIds) supporting the subsequent CPC may be provided. As another example, the enablement of the subsequent CPC may be configured for the conditional reconfiguration entry.

[0069] It should be understood that the conditional reconfiguration may include any other suitable information, for example, the conditional reconfiguration may further include an execution condition for the CPA / CPC evaluation associated with each candidate cell.

[0070] Upon receiving the conditional reconfiguration, the terminal device 120 may send an RRC reconfiguration complete message to the MN 110 (308). For example, the terminal device 120 may apply the RRC configuration except for the CPA / CPC configuration, store the CPA / CPC configuration, and send the RRC reconfiguration complete message back to the MN 110.

[0071] The terminal device 120 may start evaluating the execution condition for the set of candidate cells. In some embodiments, if the set of candidate cells includes the serving cell of the terminal device 120 (in other words, one of the candidate cells is the PSCell of the terminal device 120), the terminal device 120 may not perform a conditional reconfiguration evaluation for the corresponding candidate cell. In some embodiments, if the candidate cell is different from the serving cell of the terminal device 120 (in other words, if the candidate cell is not the PSCell of the terminal device 120), the terminal device 120 may perform a conditional reconfiguration evaluation for the candidate cell.

[0072] In some embodiments, the terminal device 120 may detect that an execution condition for a candidate cell (also referred to herein as a selected candidate cell) is met (309). In this case, the terminal device 120 may perform a cell change, i.e., CPC. In some embodiments, if an execution condition for a candidate cell is met and the candidate cell is different from the serving cell of the terminal device 120 (in other words, if the candidate cell is not a PSCell of the terminal device 120), the terminal device 120 may perform CPC for the candidate cell. In some embodiments, the terminal device 120 may receive an RRCReconfiguration message including reconfigurationWithSync before an execution condition for any candidate cell is met (309'). In this case, the terminal device 120 may also perform a cell change, i.e., a conventional PSCell change.

[0073] For a cell change (CPC or conventional PSCell change), the terminal device 120 may apply an RRC reconfiguration message corresponding to the target SN and send (310) an MN RRC reconfiguration complete message to the MN 110. The MN RRC reconfiguration complete message includes an SN RRC reconfiguration complete message for the target SN and information of the selected candidate cell (e.g., a conditional reconfiguration ID).

[0074] After the cell change, the terminal device 120 does not delete (i.e., maintains) the stored CPA / CPC configuration and associated measurement configuration, and continues to evaluate the execution conditions for the candidate cell. In some embodiments, the terminal device 120 may maintain all entries in the stored CPA / CPC configuration. In some embodiments, the terminal device 120 may delete entries of conditional reconfiguration and associated measurement configuration where subsequent CPC is not enabled (i.e., disabled), and maintain entries of conditional reconfiguration and associated measurement reconfiguration where subsequent CPC is enabled. In this way, subsequent CPC is facilitated.

[0075] Upon receiving the MN RRC Reconfiguration Complete message, the MN 110 may send (311) a notification to the source SN 130 indicating that the provision of user data to the terminal device 120 has been stopped. In some embodiments, this notification may include the address of the selected candidate cell. If the address is applicable, the source SN 130 may initiate late data forwarding.

[0076] The MN 110 may send 312 an SN RRC Reconfiguration Complete message contained in a MN RRC Reconfiguration Complete message to the target SN (in this example, target SN 140).

[0077] The terminal device 120 may then perform synchronization to the selected candidate cell (i.e., the target SN 140) (313). The source SN 130 may send an SN status transition to the MN 110 (314). The MN 110 may forward the SN status transition to the target SN 140 (315). Data forwarding 316 may be performed from the source SN to the target SN 140. The source SN may send a Secondary RAT Data Usage Report message to the MN 110 (317). An update 318 of the UP path to the core network may be performed via a PDU Session Path Update procedure. The MN 110 may send a UE Context Release message to the source SN 130 (319). The source SN 130 may release radio and control plane related resources associated with the UE context. Then, one or more subsequent CPCs 320 may be performed. The following describes the details of the subsequent CPCs with reference to FIG. 5.

[0078] 3. Implementation of SN-initiated CPC with subsequent CPC 4 is a schematic diagram illustrating an example process 400 of SN-initiated CPC with subsequent CPC according to an embodiment of the present disclosure. For illustrative purposes, the process 400 is described with reference to FIG. 1. The process 400 may involve the terminal device 120, the network devices 110, 130, 140 and 150, the UPF 161 and the AMF 162 as shown in FIG. 1. In this example, the network device 110 is a MN serving the terminal device 110, the network device 130 is a source SN serving the terminal device 110, and the network devices 140 and 150 are potential target SNs serving the terminal device 110.

[0079] As shown in FIG. 4, the source SN 130 may send a request for CPC to the MN 110 (401). In some embodiments, the request for CPC may include information indicating that a subsequent CPC has been activated for at least one candidate cell in the set of candidate cells. In some embodiments, the request for CPC may include a data forwarding address associated with the source SN 130. For example, the source SN 130 may decide to configure a CPC and the activation of a subsequent CPC for the terminal device 110. In this case, the source SN 130 may send the request for CPC.

[0080] Upon receiving the request for the CPC from source SN 130, MN 110 may send a request for resource allocation to target SN 140 (402). MN 110 may also send a request for resource allocation to target SN 150 (402').

[0081] In some embodiments, the request for resource allocation may be an SN Addition Request message. Of course, any other suitable message is also possible. In some embodiments, the request for resource allocation may include information indicating that a subsequent CPC has been enabled for the at least one candidate cell. For example, the request for resource allocation may include at least one of an indication indicating that a subsequent CPC has been enabled or a list of candidate PSCells indicating the at least one candidate cell for which a subsequent CPC has been enabled. Thus, the enablement of the subsequent CPC may be applied to all cells in the list of candidate PSCells or may be applied to a portion of cells in the list of candidate PSCells.

[0082] For an SN-initiated CPC, the execution condition is based on the measurement configuration. In the conventional solution, the target SN may not obtain the source SN's measurement configuration for the SN-initiated CPC and may reconfigure the source SN's measurement ID. In this case, the terminal device cannot obtain the correct execution condition of the subsequent CPC. Therefore, in some embodiments, the request for resource allocation may include information of the measurement configuration associated with the source SN 130. In this way, the terminal device 120 can know the execution condition of the subsequent CPC accurately.

[0083] It should be understood that the request for resource allocation may further include any other suitable information. For example, the request may include another list of candidate PSCells indicating all candidate PSCells for the terminal device 120.

[0084] 4, target SN 140 may send an acknowledgment for the request to MN 110 (403). The acknowledgment for the request may include an acknowledgment for the subsequent CPC activation and a data forwarding address associated with target SN 140. Similarly, target SN 150 may send an acknowledgment for the request to MN 110 (403'). The acknowledgment for the request may include an acknowledgment for the subsequent CPC activation and a data forwarding address associated with target SN 150.

[0085] The MN 110 may indicate (404) one or more candidate PSCells that have been accepted by the target SN to the source SN 130. The source SN 130 may send an updated measurement configuration to the MN 110 (405).

[0086] The MN 110 may send a data forwarding address to the target SN 140 (406) and may also send a data forwarding address to the target SN 150 (406'). In some embodiments, the data forwarding address may include a data forwarding address associated with the MN 110. Thus, the MN 110 provides indirect data forwarding between the source SN and the target SN. In some embodiments, the data forwarding address may include a data forwarding address associated with one or more other target SNs. For example, the MN 110 may send a data forwarding address associated with the target SN 150 to the target SN 140 and may also send a data forwarding address associated with the target SN 140 to the target SN 150. In some embodiments, the data forwarding address may include a data forwarding address associated with the source SN 130. For example, the MN 110 may send a data forwarding address associated with the source SN 130 to the target SN 140 and to the target SN 150. Thus, direct data forwarding between the target SN and the source SN may be enabled.

[0087] The MN 110 may send 407 a data forwarding address to the source SN 130. In some embodiments, the data forwarding address may include a data forwarding address associated with the MN 110, thus providing indirect data forwarding between the source SN and the target SN. In some embodiments, the data forwarding address may include a data forwarding address associated with the target SNs 140 and 150, thus enabling direct data forwarding.

[0088] 4, the MN 110 may send a conditional reconfiguration for the set of candidate cells to the terminal device 120 (408). For example, the MN 110 may send an RRCReconfiguration message including the conditional reconfiguration to the terminal device 120. Of course, any other suitable message is also possible.

[0089] In some embodiments, the conditional reconfiguration may include information indicating that a subsequent CPC has been enabled for at least one candidate cell in the set of candidate cells. That is, the information indicating the enablement of the subsequent CPC may apply to all conditional reconfiguration entries (i.e., all candidate PSCells). Alternatively, the information indicating the enablement of the subsequent CPC may apply only to a portion of the conditional reconfiguration entries (i.e., a portion of the candidate PSCells). For example, a list of conditional reconfiguration IDs (CondReconfigIds) supporting the subsequent CPC may be provided. As another example, the enablement of the subsequent CPC may be configured for the conditional reconfiguration entry.

[0090] It should be understood that the conditional reconfiguration may include any other suitable information, for example, the conditional reconfiguration may further include an execution condition for the CPA / CPC evaluation associated with each candidate cell.

[0091] Upon receiving the conditional reconfiguration, the terminal device 120 may transmit an RRC reconfiguration complete message to the MN 110 (409). For example, the terminal device 120 may apply the RRC configuration except for the CPA / CPC configuration, store the CPA / CPC configuration, and return the RRC reconfiguration complete message to the MN 110.

[0092] The terminal device 120 may start evaluating the execution condition for the set of candidate cells. In some embodiments, if the set of candidate cells includes the serving cell of the terminal device 120 (in other words, one of the candidate cells is the PSCell of the terminal device 120), the terminal device 120 may not perform a conditional reconfiguration evaluation for the corresponding candidate cell. In some embodiments, if the candidate cell is different from the serving cell of the terminal device 120 (in other words, if the candidate cell is not the PSCell of the terminal device 120), the terminal device 120 may perform a conditional reconfiguration evaluation for the candidate cell.

[0093] In some embodiments, the terminal device 120 may detect that an execution condition for a candidate cell (also referred to herein as a selected candidate cell) is met (410). In this case, the terminal device 120 may perform a cell change, i.e., CPC. In some embodiments, if the execution condition for the candidate cell is met and the candidate cell is different from the serving cell of the terminal device 120 (in other words, if the candidate cell is not a PSCell of the terminal device 120), the terminal device 120 may perform CPC for the candidate cell. In some embodiments, the terminal device 120 may receive an RRCReconfiguration message including reconfigurationWithSync before the execution condition for any candidate cell is met (410'). In this case, the terminal device 120 may also perform a cell change, i.e., a conventional PSCell change.

[0094] For a cell change (CPC or conventional PSCell change), the terminal device 120 may apply an RRC reconfiguration message corresponding to the target SN and send (411) an MN RRC reconfiguration complete message to the MN 110. The MN RRC reconfiguration complete message includes an SN RRC reconfiguration complete message for the target SN and information of the selected candidate cell (e.g., a conditional reconfiguration ID).

[0095] After the cell change, the terminal device 120 does not delete (i.e., maintains) the stored CPA / CPC configuration and associated measurement configuration, and continues to evaluate the execution conditions for the candidate cell. In some embodiments, the terminal device 120 may maintain all entries in the stored CPA / CPC configuration. In some embodiments, the terminal device 120 may delete entries for conditional reconfiguration and associated measurement reconfiguration where the subsequent CPC is not enabled (i.e., disabled), and maintain entries for conditional reconfiguration and associated measurement reconfiguration where the subsequent CPC is enabled. In this way, subsequent CPC is facilitated.

[0096] Upon receiving the MN RRC Reconfiguration Complete message, the MN 110 may send 412 a notification to the source SN 130 indicating that the provision of user data to the terminal device 120 has been stopped. In some embodiments, this notification may include the address of the selected candidate cell. If the address is applicable, the source SN 130 may initiate late data forwarding.

[0097] The MN 110 may send 413 an SN RRC Reconfiguration Complete message contained in a MN RRC Reconfiguration Complete message to the selected candidate cell (in this example, the target SN 140).

[0098] The terminal device 120 may then perform 414 synchronization to the selected candidate cell (i.e., the target SN 140). The source SN 130 may send 415 an SN status transition to the MN 110. The MN 110 may forward 416 the SN status transition to the target SN 140. Data forwarding 417 may be performed from the source SN to the target SN 140. The source SN may send 418 a Secondary RAT Data Usage Report message to the MN 110. An update 419 of the UP path to the core network may be performed via a PDU Session Path Update procedure. The MN 110 may send 420 a UE Context Release message to the source SN 130. The source SN 130 may release radio and control plane related resources associated with the UE context. Then, one or more subsequent CPCs 421 may be performed. The following describes the subsequent CPCs in detail with reference to FIG. 5.

[0099] 4. Examples of subsequent CPC implementations 5 is a schematic diagram illustrating an example process 500 of a subsequent CPC according to an embodiment of the present disclosure. For illustrative purposes, the process 500 is described with reference to FIG. 1. The process 500 may involve the terminal device 120, the network devices 110, 130, 140 and 150, the UPF 161 and the AMF 162 as shown in FIG. 1. The process 500 may implement the subsequent CPC 213, 320 or 421.

[0100] In this example, the network device 110 is an MN serving the terminal device 110, and the network device 150 is a potential target SN serving the terminal device 110. The current SN is a network device of a current serving cell of the terminal device 110. For convenience, the target SN 140 may be described below as an example of a current SN.

[0101] After a conventional PSCell change / addition, CPA, or CPC, the terminal device 120 may continue to evaluate the execution conditions for at least one subsequent CPC-enabled candidate cell.

[0102] In some embodiments, if the set of candidate cells includes the serving cell of terminal device 120 (in other words, one of the candidate cells is a PSCell of terminal device 120), terminal device 120 may not perform a conditional reconfiguration evaluation for the corresponding candidate cell. In some embodiments, if a candidate cell is different from the serving cell of terminal device 120 (in other words, if the candidate cell is not a PSCell of terminal device 120), terminal device 120 may perform a conditional reconfiguration evaluation for the candidate cell.

[0103] If the execution condition for a candidate cell (hereinafter also referred to as a selected candidate cell) is satisfied, the terminal device 120 may perform subsequent CPC. In this example, the selected candidate cell is provided by the target SN 150. In some embodiments, if the execution condition for the candidate cell is satisfied and the candidate cell is different from the serving cell of the terminal device 120 (in other words, the candidate cell is not the PSCell of the terminal device 120), the terminal device 120 may perform subsequent CPC for the candidate cell.

[0104] 5, the terminal device 120 may send an MN RRC Reconfiguration Complete message to the MN 110 (501). The MN RRC Reconfiguration Complete message includes an SN RRC Reconfiguration Complete message for the target SN 150 and information of the selected candidate cell (e.g., a conditional reconfiguration ID).

[0105] Upon receiving the MN RRC Reconfiguration Complete message, the MN 110 may send 502 a notification to the current SN 140 indicating that the provision of user data to the terminal device 120 has been stopped. In some embodiments, this notification may include the address of the selected candidate cell. If the address is applicable, the current SN 140 may initiate late data forwarding.

[0106] The MN 110 may send 503 an SN RRC Reconfiguration Complete message contained in a MN RRC Reconfiguration Complete message to the selected candidate cell (in this example, the target SN 150).

[0107] The terminal device 120 may then perform synchronization to the selected candidate cell (i.e., one of the cells of the target SN 150) (504). The Current SN 140 may send an SN status transition to the MN 110 (505). The MN 110 may forward the SN status transition to the target SN 150 (506). Data forwarding 507 may be performed from the Current SN 140 to the MN 110, the target SN (i.e., the network device 150 and the network device 130) or to at least one of the target SNs (e.g., the target SN 150 and the source SN 130). In the case of an indirect data forwarding, data is forwarded from the Current SN 140 to the MN 110, and the MN 130 forwards the data to at least one of the target SNs (e.g., the target SN 150 and the source SN 130). In the case of a direct data forwarding, the Current SN 140 forwards the data to at least one of the target SNs, e.g., the target SN 150 and the source SN 130. This data transfer may be initiated as early as after receiving an RRC reconfiguration complete message from the MN 110 or after performing a random access procedure with the terminal device 120, in other words after 208 / 209 in FIG. 2, 312 / 313 in FIG. 3, 413 / 414 in FIG. 4, or 503 / 504 in FIG. 5, after the network device becomes the current SN 140 of the UE. The current SN 140 may send a Secondary RAT Data Usage Report message to the MN 110 (508). An update of the UP path to the core network 509 may be performed via a PDU Session Path Update procedure. The MN 110 may send a UE Context Release message to the current SN 140 (510). The current SN 140 may release the radio and control plane related resources associated with the UE context. More subsequent CPCs can be performed by repeating the above process 500.

[0108] Up to this point, a procedure for enabling and executing a subsequent CPC is provided. It should be understood that the above process also applies to changing or adding a conditional PCell.

[0109] It should be understood that the steps and the order of steps in FIGS. 2-5 are for illustration only and not for limitation.

[0110] 5. Example of avoiding the PING-PONG problem of subsequent CPCs If CPA / CPC is configured in the UE and subsequent CPC is supported, the UE may perform execution condition evaluation. In case of frequent cell change, a ping-pong problem may occur. For example, the UE may perform PSCell change back and forth and stay in each cell for a short time, which may cause poor performance.

[0111] The embodiments of the present disclosure provide a solution to avoid the above ping-pong problem, in which a timer is set to control the conditional reset evaluation for subsequent CPCs.

[0112] In some embodiments, the terminal device 120 may receive a timer setting from the MN 110. If a cell change or addition (conventional or conditional) or a subsequent conditional cell change is successfully completed, the terminal device 120 may start the timer while pausing the conditional reconfiguration evaluations. If the timer expires, the terminal device 120 may resume the conditional reconfiguration evaluations.

[0113] In this way, the ping-pong problem can be alleviated.

[0114] Example of the method Therefore, the embodiments of the present disclosure provide communication methods implemented in a terminal device and a network device, which are described below with reference to Figures 6 to 10.

[0115] 6 illustrates an example communication method 600 implemented in a terminal device, according to some embodiments of the present disclosure. For example, the method 600 may be performed in a terminal device 120 as shown in FIG. For purposes of explanation, the method 600 will be described below with reference to FIG. 1. It should be understood that the method 600 may include additional blocks not shown and / or omit some blocks that are shown, and that the scope of the present disclosure is not limited in this respect.

[0116] In block 610, the terminal device 120 receives a conditional reconfiguration for a set of candidate cells from a first network device (e.g., network device 110) as an MN, the conditional reconfiguration including information indicating that a subsequent conditional cell change has been enabled for at least one candidate cell in the set of candidate cells.

[0117] In block 620, the terminal device 120 determines whether a cell change or addition has been performed. In some embodiments, the terminal device 120 may perform a conditional reconfiguration evaluation for the set of candidate cells based on the conditional reconfiguration. If a condition for a candidate cell in the set of candidate cells is satisfied, the terminal device 120 may perform a cell change or addition for the candidate cell. In some embodiments, if the candidate cell is the serving cell of the terminal device 120, the terminal device 120 may not perform a conditional reconfiguration evaluation for the candidate cell. In some embodiments, if the candidate cell is different from the serving cell of the terminal device 120, the terminal device 120 may perform a cell change or addition for the candidate cell.

[0118] If a cell change or addition has been performed, process 600 proceeds to block 630. In block 630, terminal device 120 maintains at least a portion of the conditional reconfiguration for use in subsequent conditional cell changes.

[0119] In some embodiments, terminal device 120 may perform a conditional reconfiguration evaluation for the at least one candidate cell in the set of candidate cells based on the conditional reconfiguration. If a condition for a candidate cell in the at least one candidate cell is satisfied, terminal device 110 may perform the subsequent conditional cell change to the candidate cell. In some embodiments, terminal device 120 may not perform a conditional reconfiguration evaluation for a candidate cell if the candidate cell is a serving cell of terminal device 120. In some embodiments, terminal device 120 may perform the subsequent conditional cell change to the candidate cell if the candidate cell is different from the serving cell of terminal device 120.

[0120] In some embodiments, the terminal device 120 may further receive a setting for the timer from the network device 130. If the cell change or addition or subsequent conditional cell change is successfully completed, the terminal device 120 may start the timer while pausing the conditional reconfiguration evaluations. If the timer expires, the terminal device 120 may resume the conditional reconfiguration evaluations.

[0121] In some embodiments, terminal device 120 may maintain the conditional reconfiguration for the set of candidate cells. In some embodiments, terminal device 120 may remove the conditional reconfiguration for at least one candidate cell of the set of candidate cells for which the subsequent conditional cell change is disabled (also referred to herein as a second portion) while maintaining the conditional reconfiguration for the at least one candidate cell (also referred to herein as a first portion).

[0122] It is thus possible to provide a procedure for subsequent conditional cell changes after a cell change or addition.

[0123] 7 illustrates an example communication method 700 implemented in a first network device as a MN according to some embodiments of the present disclosure. For example, the method 700 may be performed in the network device 110 as shown in FIG. 1. The network device 110 may be a MN. For purposes of explanation, the method 700 will be described below with reference to FIG. 1. It should be understood that the method 700 may include additional blocks not shown and / or omit some blocks that are shown, and that the scope of the present disclosure is not limited in this respect.

[0124] As shown in FIG. 7, in block 710, the network device 110 sends to the terminal device 120 a conditional reconfiguration for a set of candidate cells, the conditional reconfiguration including information indicating that a subsequent conditional cell change has been enabled for at least one candidate cell in the set of candidate cells.

[0125] In some embodiments, network device 110 may further send a request for resource allocation to a set of second network devices (e.g., network devices 140 and 150), the request including information indicating that the subsequent conditional cell change has been enabled for the at least one candidate cell.

[0126] In some embodiments, network device 110 may receive from each second network device in the set of second network devices an acknowledgment of the enablement of the subsequent conditional cell change and a data forwarding address associated with the second network device.

[0127] In some embodiments, network device 110 may further send a message to a third network device (e.g., network device 130) as a source SN, including information indicating that the subsequent conditional cell change has been enabled for the at least one candidate cell. In some embodiments, network device 110 may further receive an acknowledgement from the third network device for the enablement of the subsequent conditional cell change. In some embodiments, the acknowledgement may include a data forwarding address associated with the third network device.

[0128] In some embodiments, network device 110 may further receive a request for a conditional cell change from the third network device, the request including at least one of a data forwarding address associated with the third network device or the information indicating that the subsequent conditional cell change has been enabled for the at least one candidate cell in the set of candidate cells.

[0129] In some embodiments, the network device 110 may further transmit information of the measurement configuration of the third network device to the set of second network devices.

[0130] In some embodiments, network device 110 may transmit a data forwarding address to the set of second network devices, in some embodiments, the data forwarding address includes at least one of a data forwarding address associated with the third network device, a data forwarding address associated with the first network device, or a data forwarding address associated with the set of second network devices.

[0131] In some embodiments, the network device 110 may forward data received from the terminal device's serving network device to at least one of the set of second network devices.

[0132] In some embodiments, the network device 110 may send a timer configuration to the terminal device 120 such that conditional reconfiguration evaluations for subsequent conditional cell changes are suspended while the timer runs.

[0133] It is thus possible to provide a procedure for subsequent conditional cell changes after a cell change or addition.

[0134] 8 illustrates an example communication method 800 implemented in a second network device as a target SN, according to some embodiments of the present disclosure. For example, method 800 may be performed in network device 140 or 150 as shown in FIG. 1. For purposes of explanation, method 800 will be described below with reference to the network device in FIG. 1. It should be understood that method 800 may include additional blocks not shown and / or omit some of the blocks shown, and that the scope of the present disclosure is not limited in this respect.

[0135] As shown in FIG. 8, in block 810, the network device 140 receives a request for resource allocation from a first network device (e.g., the network device 110) as an MN, the request including information indicating that a subsequent conditional cell change has been enabled for at least one candidate cell in the set of candidate cells.

[0136] At block 820 , network device 140 may send to network device 110 an acknowledgement of the subsequent conditional cell change activation and a data forwarding address associated with network device 140 .

[0137] In some embodiments, network device 140 may receive information of the measurement configuration of a third network device (eg, network device 130) as a source SN from network device 110.

[0138] In some embodiments, network device 140 may receive a data forwarding address from network device 110. In some embodiments, the data forwarding address includes at least one of a data forwarding address associated with network device 130, a data forwarding address associated with network device 110, or a data forwarding address associated with a set of second network devices (i.e., one or more target SNs, e.g., network device 150).

[0139] In some embodiments, network device 140 may perform data transfers to at least one of the first network device, the set of second network devices, and a third network device.

[0140] In some embodiments, the network device 140 may initiate the data transfer in response to one of receiving an RRC reconfiguration complete message from the first network device or performing a random access procedure with the terminal device 120.

[0141] It is thus possible to provide a procedure for subsequent conditional cell changes after a cell change or addition.

[0142] 9 illustrates an example communication method 900 implemented in a third network device as a source SN, according to some embodiments of the present disclosure. For example, the method 900 may be performed in a network device 130 as shown in FIG. 1. For purposes of explanation, the method 900 will be described below with reference to FIG. 1. It should be understood that the method 900 may include additional blocks not shown and / or omit some blocks that are shown, and that the scope of the present disclosure is not limited in this respect.

[0143] As shown in FIG. 9, in block 910, the network device 130 receives a message from a first network device (e.g., the network device 110) as an MN, the message including information indicating that a subsequent conditional cell change has been enabled for at least one candidate cell in the set of candidate cells.

[0144] At block 920, network device 130 sends an acknowledgement of the subsequent conditional cell change activation to network device 110. In some embodiments, the acknowledgement may include a data forwarding address associated with network device 130.

[0145] In some embodiments, network device 130 may receive from network device 110 a set of data forwarding addresses associated with a set of second network devices (e.g., network devices 140 and 150) and perform data forwarding to the set of second network devices based on the set of data forwarding addresses.

[0146] In this way it is possible to support subsequent conditional cell changes after a cell change or addition.

[0147] 10 illustrates an example communication method 1000 implemented in a third network device as a source SN according to some embodiments of the present disclosure. For example, the method 1000 may be performed in a network device 130 as shown in FIG. 1. For purposes of explanation, the method 1000 will be described below with reference to FIG. 1. It should be understood that the method 1000 may include additional blocks not shown and / or omit some blocks that are shown, and that the scope of the present disclosure is not limited in this respect.

[0148] In block 1010, the network device 130 sends a request for a conditional cell change to a first network device (e.g., the network device 110) as the MN, the request including at least one of a data forwarding address associated with the network device 130 or information indicating that a subsequent conditional cell change has been enabled for at least one candidate cell in the set of candidate cells.

[0149] In some embodiments, network device 130 may receive from network device 110 a set of data forwarding addresses associated with a set of second network devices (e.g., network devices 140 and 150) and perform data forwarding to the set of second network devices based on the set of data forwarding addresses.

[0150] In this way it is possible to enable subsequent conditional cell change procedures after a cell change or addition.

[0151] Device implementation examples Fig. 11 is a schematic block diagram of an apparatus 1100 suitable for implementing embodiments of the present disclosure. The apparatus 1100 may be considered as another exemplary implementation of the terminal apparatus 120 or the network apparatus 110, 130, 140 or 150 shown in Fig. 1. Thus, the apparatus 1100 may be implemented in or as at least a part of the terminal apparatus 110 or the network apparatus 110, 130, 140 or 150.

[0152] As shown, the apparatus 1100 comprises a processor 1110, a memory 1120 coupled to the processor 1110, a suitable transmitter (TX) and receiver (RX) 1140 coupled to the processor 1110, and a communication interface coupled to the TX / RX 1140. The memory 1120 stores at least a portion of a program 1130. The TX / RX 1140 is used for bidirectional communication. The TX / RX 1140 has at least one antenna to facilitate communication, although the access nodes referred to herein may in practice have multiple antennas. The communication interface may represent any interface required for communication with other network elements, such as an X2 / Xn interface for bidirectional communication between eNBs / gNBs, an S1 / NG interface for communication between a Mobility Management Entity (MME) / Access and Mobility Management Function (AMF) / SGW / UPF and an eNB / gNB, an Un interface for communication between an eNB / gNB and a relay node (RN), or a Uu interface for communication between an eNB / gNB and a terminal device.

[0153] The program 1130 is assumed to include program instructions that, when executed by the associated processor 1110, enable the device 1100 to operate according to embodiments of the present disclosure, as described herein with reference to Figures 1-10. The embodiments of the present disclosure may be realized by computer software executable by the processor 1110 of the device 1100, or by hardware, or by a combination of software and hardware. The processor 1110 may be configured to implement various embodiments of the present disclosure. Furthermore, the combination of the processor 1110 and the memory 1120 may form a processing means 1150 suitable for implementing various embodiments of the present disclosure.

[0154] The memory 1120 may be of any type suitable for a local technology network and may be implemented using any suitable data storage technology, such as, by way of non-limiting example, non-transitory computer-readable storage media, semiconductor-based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory and removable memory. Although only one memory 1120 is shown in the device 1100, there may be several physically different memory modules in the device 1100. The processor 1110 may be of any type suitable for a local technology network and may include, by way of non-limiting example, one or more of a general purpose computer, a special purpose computer, a microprocessor, a digital signal processor (DSP) and a processor based on a multi-core processor architecture. The device 1100 may have multiple processors, for example application specific integrated circuit chips time-slaved to a clock that synchronizes the main processor.

[0155] In some embodiments, a terminal device comprises circuitry configured to receive from a first network device a conditional reconfiguration for a set of candidate cells, the conditional reconfiguration including information indicating that a subsequent conditional cell change has been enabled for at least one candidate cell in the set of candidate cells, and to maintain at least a portion of the conditional reconfiguration for use in the subsequent conditional cell change pursuant to a determination that a cell change or addition has been performed.

[0156] In some embodiments, the circuitry may be further configured to perform a conditional reset evaluation for the at least one candidate cell in the set of candidate cells based on the conditional reset, and perform the subsequent conditional cell change for the candidate cell in accordance with a determination that a condition is satisfied for a candidate cell in the at least one candidate cell.

[0157] In some embodiments, the circuitry may be further configured to not perform a conditional reconfiguration evaluation for the candidate cell pursuant to determining that the candidate cell is a serving cell of the terminal device.

[0158] In some embodiments, the circuitry may be configured to perform the subsequent conditional cell change by performing the subsequent conditional cell change to the candidate cell in accordance with a determination that the candidate cell is different from a serving cell of the terminal device.

[0159] In some embodiments, the circuitry may be further configured to perform a conditional reset evaluation for the set of candidate cells based on the conditional reset, and perform the cell change or addition for the candidate cell in accordance with a determination that a condition is satisfied for a candidate cell in the set of candidate cells.

[0160] In some embodiments, the circuitry may be further configured to not perform a conditional reconfiguration evaluation for the candidate cell pursuant to determining that the candidate cell is a serving cell of the terminal device.

[0161] In some embodiments, the circuitry may be configured to perform the cell change or addition by performing the cell change or addition to the candidate cell in accordance with a determination that the candidate cell is different from a serving cell of the terminal device.

[0162] In some embodiments, the circuitry may be further configured to receive a timer setting from the first network device, and, pursuant to a determination that the cell change or add or the subsequent conditional cell change has been successfully completed, start the timer while pausing conditional reset evaluations, and, pursuant to a determination that the timer has expired, resume the conditional reset evaluations.

[0163] In some embodiments, the circuitry may be configured to maintain the at least a portion of the conditional reconfiguration for the set of candidate cells, or by maintaining a first portion of the conditional reconfiguration for the at least one candidate cell while removing a second portion of the conditional reconfiguration for at least one candidate cell of the set of candidate cells for which the subsequent conditional cell change is disabled.

[0164] In some embodiments, the first network device comprises circuitry configured to transmit a conditional reconfiguration for a set of candidate cells to a terminal device, the conditional reconfiguration including information indicating that a subsequent conditional cell change has been enabled for at least one candidate cell in the set of candidate cells.

[0165] In some embodiments, the circuitry may be further configured to send a request for resource allocation to a set of second network devices, the request including information indicating that the subsequent conditional cell change has been enabled for the at least one candidate cell.

[0166] In some embodiments, the circuitry may be further configured to receive, from a second network device in the set of second network devices, an acknowledgment of the enablement of the subsequent conditional cell change and a data forwarding address associated with the second network device.

[0167] In some embodiments, the circuitry may be further configured to send a message to a third network device including information indicating that the subsequent conditional cell change has been enabled for the at least one candidate cell. In some embodiments, the circuitry may be further configured to receive an acknowledgement from the third network device regarding the enablement of the subsequent conditional cell change. In some embodiments, the acknowledgement may include a data forwarding address associated with the third network device.

[0168] In some embodiments, the circuitry may be further configured to receive a request for a conditional cell change from a third network device, the request including at least one of a data forwarding address associated with the third network device or the information indicating that the subsequent conditional cell change has been enabled for the at least one candidate cell in the set of candidate cells.

[0169] In some embodiments, the circuitry may be further configured to transmit information of a measurement configuration of the third network device to the set of second network devices.

[0170] In some embodiments, the circuitry may further configure a data forwarding address to transmit to the set of second network devices, in some embodiments, the data forwarding address includes at least one of a data forwarding address associated with the third network device, a data forwarding address associated with the first network device, or a data forwarding address associated with the set of second network devices.

[0171] In some embodiments, the circuitry may be further configured to forward data received from a serving network device for the terminal device to at least one of a set of second network devices.

[0172] In some embodiments, the circuitry may be further configured to transmit a setting of a timer to the terminal device, wherein conditional reconfiguration evaluations for the subsequent conditional cell change are suspended while the timer runs.

[0173] In some embodiments, the second network device comprises circuitry configured to receive a request for resource allocation from a first network device, the request including information indicating that a subsequent conditional cell change has been enabled for at least one candidate cell in a set of candidate cells, and to transmit to the first network device an acknowledgement of the enablement of the subsequent conditional cell change and a data forwarding address associated with the second network device.

[0174] In some embodiments, the circuitry may be further configured to receive from the first network device information of a measurement configuration of a third network device.

[0175] In some embodiments, the circuitry may be further configured to receive a data transfer address from the first network device, in some embodiments, the data transfer address includes at least one of a data transfer address associated with a third network device, a data transfer address associated with the first network device, or a data transfer address associated with a set of second network devices.

[0176] In some embodiments, the circuitry may be further configured to perform a data transfer to at least one of the first network device, a set of second network devices, and a third network device.

[0177] In some embodiments, the circuitry may be further configured to initiate the data transfer in response to one of receiving an RRC reconfiguration complete message from the first network device or performing a random access procedure with the terminal device.

[0178] In some embodiments, the third network device comprises circuitry configured to receive from the first network device a message including information indicating that a subsequent conditional cell change has been enabled for at least one candidate cell in a set of candidate cells, and to send an acknowledgement to the first network device for the enablement of the subsequent conditional cell change. In some embodiments, the acknowledgement may include a data forwarding address associated with the third network device.

[0179] In some embodiments, the circuitry may be further configured to receive from the first network device a set of data transfer addresses associated with a set of second network devices, and to perform data transfers to the set of second network devices based on the set of data transfer addresses.

[0180] In some embodiments, the third network device comprises circuitry configured to send a request for a conditional cell change to the first network device at the third network device, the request including at least one of a data forwarding address associated with the third network device or information indicating that a subsequent conditional cell change has been enabled for at least one candidate cell in a set of candidate cells.

[0181] In some embodiments, the circuitry may be further configured to receive from the first network device a set of data transfer addresses associated with a set of second network devices, and to perform data transfers to the set of second network devices based on the set of data transfer addresses.

[0182] The term "circuitry" as used herein 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 analog and / or digital hardware circuitry and software / firmware. As yet another example, a circuit may be any portion of a hardware processor having software, including a digital signal processor, software, and one or more memories, that cooperate to cause a device, such as a terminal device or a 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 portion thereof, that requires software / firmware for operation, but the software may not be present if not required for operation. As used herein, the term "circuitry" also includes an implementation of only a hardware circuit or one or more processors, or a portion of a hardware circuit or one or more processors and its (or their) associated software and / or firmware.

[0183] Overall, various embodiments of the present disclosure may be implemented in hardware or special purpose circuits, software, logic, or any combination thereof. Some aspects may be implemented in hardware, while other aspects may be implemented in firmware or software that may be executed by a controller, microprocessor, or other computing device. Although various aspects of the embodiments of the present disclosure have been illustrated and described using block diagrams, flow charts, or some other pictorial representations, it should be understood that the blocks, devices, systems, techniques, or methods described herein may be implemented, by way of non-limiting examples, in hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing device, or any combination thereof.

[0184] The present disclosure also provides at least one computer program product tangibly stored on a non-transitory computer-readable storage medium. The computer program product includes computer-executable instructions, such as instructions included in a program module, that execute in a device on a target real or virtual processor to perform a process or method as described above with reference to Figures 1-10. Generally, program modules include routines, programs, libraries, objects, classes, components, data structures, etc. that perform particular tasks or implement particular abstract data types. In various embodiments, the functionality of the program modules may be combined or split between program modules as appropriate. The machine-executable instructions of the program modules may be executed in local or distributed devices. In a distributed device, the program modules may be located in both local and remote storage media.

[0185] Program codes for carrying out the methods of the present 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 special purpose computer, or other programmable data processing device, and when executed by the processor or controller, the program code causes the functions / operations specified in the flowcharts and / or block diagrams to be implemented. The program code may run entirely on the machine, partially on the machine, as a separate software package, partially on the machine and partially on a remote machine, or entirely on a remote machine or server.

[0186] The above program code may be implemented on a machine-readable medium, which may be any tangible medium that can contain or store a program 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, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, device, or apparatus, or any suitable combination of the aforementioned media. More specific examples of the machine-readable storage medium may include an electrical connection having one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the aforementioned.

[0187] It should be noted that although operations have been described in a particular order, it should not be understood that such operations are required to be performed in the particular order shown, or in any sequential order, or to perform all of the operations described, in order to achieve desired results. In some cases, multitasking and parallel processing may be advantageous. Similarly, although some specific implementation details are included in the above discussion, these should not be construed as limitations on the scope of the disclosure, but rather as descriptions of features that may be specific to certain embodiments. Some features described in the context of individual embodiments may be realized in combination in a single embodiment. Conversely, various features described in the context of a single embodiment may be implemented in multiple embodiments separately or in any suitable subcombination.

[0188] Although the present disclosure has been described in language specific to structural features and / or methodological acts, it should be understood that the present disclosure, as defined in the appended claims, is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.

Claims

1. 1. A method of communication comprising: receiving, at a terminal device, a conditional reconfiguration for a set of candidate cells from a first network device, the conditional reconfiguration including information indicating that a subsequent conditional cell change has been enabled for at least one candidate cell in the set of candidate cells; maintaining at least a portion of the conditional reconfiguration for use in the subsequent conditional cell change pursuant to a determination that a cell change or addition has been performed; and A method comprising:

2. performing a conditional reset evaluation for the at least one candidate cell in the set of candidate cells based on the conditional reset; performing the subsequent conditional cell change to a candidate cell in accordance with a determination that a condition for the candidate cell in the at least one candidate cell is satisfied; The method of claim 1 further comprising:

3. not performing a conditional reconfiguration evaluation for the candidate cell in accordance with a determination that the candidate cell is a serving cell of the terminal device; The method of claim 2 , further comprising:

4. performing the subsequent conditional cell change performing the subsequent conditional cell change to the candidate cell according to a determination that the candidate cell is different from a serving cell of the terminal device. The method of claim 2.

5. performing a conditional reconfiguration evaluation for the set of candidate cells based on the conditional reconfiguration; performing the cell change or addition on a candidate cell in the set of candidate cells according to a determination that a condition is satisfied for the candidate cell; and The method of claim 1 further comprising:

6. not performing a conditional reconfiguration evaluation for the candidate cell in accordance with a determination that the candidate cell is a serving cell of the terminal device; The method of claim 5 further comprising:

7. performing the cell change or addition, According to a determination that the candidate cell is different from a serving cell of the terminal device, performing the cell change or addition to the candidate cell. The method according to claim 5.

8. receiving a timer setting from the first network device; starting the timer while pausing conditional reconfiguration evaluations pursuant to a determination that the cell change or addition or the subsequent conditional cell change has been successfully completed; resuming said conditional reset evaluation in accordance with a determination that said timer has expired; The method of claim 1 further comprising:

9. maintaining the at least a portion of the conditional reset maintaining the conditional reconfiguration for the set of candidate cells; or removing a second portion of the conditional reconfiguration for at least one candidate cell of the set of candidate cells for which the subsequent conditional cell change is disabled, while maintaining a first portion of the conditional reconfiguration for the at least one candidate cell. The method of claim 1.

10. 1. A method of communication comprising: transmitting, in the first network device, a conditional reconfiguration for a set of candidate cells to a terminal device; the conditional reconfiguration includes information indicating that a subsequent conditional cell change has been enabled for at least one candidate cell in the set of candidate cells. method.

11. transmitting a request for a resource allocation to a second network device of the set; the request includes the information indicating that the subsequent conditional cell change has been enabled for the at least one candidate cell. The method of claim 10.

12. receiving, from a second network device in the set of second network devices, an acknowledgement of the activation of the subsequent conditional cell change and a data forwarding address associated with the second network device; The method of claim 11 further comprising:

13. sending a message to a third network device including the information indicating that the subsequent conditional cell change has been enabled for the at least one candidate cell; The method of claim 10 further comprising:

14. receiving an acknowledgement from the third network device regarding the activation of the subsequent conditional cell change; The method of claim 13 further comprising:

15. the acknowledgement includes a data forwarding address associated with the third network device. The method of claim 14.

16. receiving a request for a conditional cell change from a third network device; the request includes at least one of a data forwarding address associated with the third network device or the information indicating that the subsequent conditional cell change has been enabled for the at least one candidate cell in the set of candidate cells. The method of claim 11.

17. transmitting information of the measurement configuration of the third network device to the set of second network devices; The method of claim 11 further comprising:

18. transmitting a data forwarding address to said set of second network devices; The method of claim 11 further comprising:

19. the data forwarding address includes at least one of a data forwarding address associated with the third network device, a data forwarding address associated with the first network device, or a set of data forwarding addresses associated with the set of second network devices; 20. The method of claim 18.

20. forwarding data received from the serving network device of the terminal device to at least one of a set of second network devices; The method of claim 10 further comprising:

21. transmitting a timer setting to the terminal device; conditional reconfiguration evaluation for the subsequent conditional cell change is paused while the timer runs. The method of claim 10.

22. 1. A method of communication comprising: receiving, at a second network device, a request for resource allocation from a first network device, the request including information indicating that a subsequent conditional cell change has been enabled for at least one candidate cell in a set of candidate cells; sending to the first network device an acknowledgement of the activation of the subsequent conditional cell change and a data forwarding address associated with the second network device; A method comprising:

23. receiving information of a measurement configuration of a third network device from the first network device; 23. The method of claim 22, further comprising:

24. receiving a data forwarding address from the first network device; 23. The method of claim 22, further comprising:

25. the data forwarding address includes at least one of a data forwarding address associated with a third network device, a data forwarding address associated with the first network device, or a set of data forwarding addresses associated with a set of second network devices; 25. The method of claim 24.

26. performing a data transfer to at least one of the first network device, a set of second network devices, and a third network device; 25. The method of claim 24, further comprising:

27. The data transfer receiving a radio resource control (RRC) reconfiguration complete message from the first network device; or performing a random access procedure with the terminal device; Initiating in response to one of 27. The method of claim 26, further comprising:

28. 1. A method of communication comprising: receiving, at a third network device, a message from the first network device, the message including information indicating that a subsequent conditional cell change has been enabled for at least one candidate cell in the set of candidate cells; sending an acknowledgement to the first network device regarding the activation of the subsequent conditional cell change; A method comprising:

29. the acknowledgement includes a data forwarding address associated with the third network device.

30. The method of claim 28.

30. 1. A method of communication comprising: transmitting, at the third network device, a request for a conditional cell change to the first network device; the request includes at least one of a data forwarding address associated with the third network device, or information indicating that a subsequent conditional cell change has been enabled for at least one candidate cell in a set of candidate cells. method.

31. receiving from the first network device a set of data forwarding addresses associated with a set of second network devices; performing a data transfer to the set of second network devices based on the set of data transfer addresses; 31. The method of claim 28 or 30, further comprising:

32. A processor configured to cause a terminal device to execute the method according to any one of claims 1 to 9, Terminal device.

33. A method comprising: a processor configured to cause a network device to perform the method according to any one of claims 10 to 21, any one of claims 22 to 27, any one of claims 28, 29 and 31, or any one of claims 30 and 31, Network device.

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