Base station device, terminal device, control method, and program for efficient management of connection setting information

Abstract

A base station device that acquires setting information for generating a plurality of cells used for conditional handover (CHO) or additional or alteration (CPAC) of a conditional secondary cell in a connected terminal device, the information including: a reference configuration common to two or more cells among the plurality of cells; identification information which uniquely determines the reference configuration is allocated to the reference configuration; an incremental configuration inherent to each of the two or more cells; and the identification information of the reference configuration that should be combined with the incremental configuration, specifies at least one of the reference configuration and the incremental configuration and instructs the terminal device to delete or change when at least one of the reference configuration and the incremental configuration is deleted or changed.

Description

Technical Field

[0001] This invention relates to an efficient management technology for wireless connection settings. Background Technology

[0002] In cellular communication systems, to ensure communication continuity, a handover technique is used to switch the connection destination of a terminal device based on factors such as the movement of the terminal device. The standard handover method is as follows: after the communication quality of the connected radio link in the terminal device deteriorates, a handover setup process is initiated on the core network side, and an instruction message is sent from the base station to the terminal device. However, in this method, the processing from the actual communication quality deterioration to the sending of the handover instruction takes time, thus extending the period of communication failure or substandard communication quality. To address this, a method is being discussed in the 3rd Generation Partnership Project (3GPP (registered trademark)) that performs this setup process in advance, and switches the cell to the connection destination without receiving an instruction message from the base station if predetermined conditions are met in the terminal device (see Non-Patent Document 1). Predetermined conditions include, for example, a case where the radio quality of a neighboring cell in the terminal device is at least a predetermined level better than the radio quality of the connected cell, or a case where the radio quality of the connected cell falls below a predetermined value. According to this method, the handover setup process on the core network side is completed before any degradation in communication quality occurs that would normally necessitate the handover, thus significantly reducing the time spent in communication failure or with substandard communication quality. Such a handover is called a conditional handover or CHO (Conditional Handover).

[0003] Similarly, in multi-connectivity (MC) systems where a terminal device connects to multiple cells, a pre-configuration process can be performed so that, if predetermined conditions are met in the terminal device, the terminal device can add or change sub-cells without receiving instruction messages from the base station device. Furthermore, this conditional addition or change of sub-cells will sometimes be referred to as CPAC.

[0004] Existing technical documents Non-patent literature Non-patent literature 1: 3GPP TR38.874, V16.0.0, December 2018 Summary of the Invention The problem that the invention aims to solve In the 3GPP Release 18 standard study, consensus was reached on two configuration processes: one using a shared reference configuration for multiple candidate cells, and the other specifying incremental configuration values ​​for each candidate cell that differ from the reference configuration. However, the execution steps for such configuration processes are not yet clearly defined, and an efficient procedure is required.

[0005] means for solving problems The present invention provides a method for efficiently performing reference configuration and incremental configuration setting processes related to the handover of incidental conditions in the terminal device, the addition or modification of incidental sub-cells.

[0006] A base station apparatus according to one aspect of the present invention comprises: an acquisition mechanism that acquires configuration information relating to a plurality of cells for generating a Conditional Handover (CHO) or a Conditional Addition or Modification (CPAC) of a secondary cell in a connected terminal device, the information comprising: a reference configuration shared by two or more of the plurality of cells, and the reference configuration being assigned identification information that uniquely identifies the reference configuration; incremental configurations inherent to each of the two or more cells; and the identification information of a reference configuration for which the incremental configurations should be combined; a providing mechanism that provides the information and conditions for executing the CHO or the CPAC to the terminal device; and an instruction mechanism that, in the event that at least one of the reference configuration and the incremental configuration is deleted or modified, instructs the terminal device to delete or modify the reference configuration and the incremental configuration.

[0007] A terminal device according to another aspect of the present invention comprises: an acquisition mechanism that acquires information and conditions from a connected base station device, the information being information for generating configuration information relating to a plurality of cells for conditional handover (CHO) or conditional addition or modification of secondary cells (CPAC), and including a reference configuration shared by two or more of the plurality of cells and an incremental configuration inherent to each of the two or more cells, the conditions being conditions for executing the CHO or the CPAC; a generation mechanism that generates configuration information for communication in at least one of the two or more cells using the incremental configuration and the reference configuration; an execution mechanism that, upon receiving an instruction specifying the deletion or modification of at least one of the reference configuration and the incremental configuration, executes the deletion or modification of the specified reference configuration and the incremental configuration; and an execution mechanism that, based on the satisfaction of the conditions, executes the CHO or the CPAC using the generated configuration information.

[0008] Invention Effects According to the present invention, it is possible to efficiently perform setting processes for reference configurations and incremental configurations related to the handover of incidental conditions in the terminal device, the addition or modification of incidental sub-cells.

[0009] Other features and advantages of the invention will become apparent from the following description with reference to the accompanying drawings. Furthermore, in the drawings, the same or identical components are labeled with the same reference numerals. Attached Figure Description

[0010] The accompanying drawings, which are included in and form a part of this specification, illustrate embodiments of the invention and, together with the description thereon, serve to explain the principles of the invention.

[0011] Figure 1 This is a diagram illustrating an example of the structure of a wireless communication system.

[0012] Figure 2 This is a diagram illustrating an example of the processing flow performed in a wireless communication system.

[0013] Figure 3 This is a diagram illustrating an example of the processing flow performed in a wireless communication system.

[0014] Figure 4 This is a diagram illustrating an example of the processing flow performed in a wireless communication system.

[0015] Figure 5 This is a diagram illustrating an example of the process for updating configuration information.

[0016] Figure 6 This is a diagram illustrating an example of the process for determining the appropriateness of the set information.

[0017] Figure 7 This is a diagram illustrating an example of the process for determining the appropriateness of the set information.

[0018] Figure 8 This is a diagram illustrating an example of the hardware configuration of MN, SN, and terminal devices.

[0019] Figure 9 This is a diagram illustrating an example of the functional configuration of a terminal device.

[0020] Figure 10 This is a diagram illustrating an example of the functional composition of MN.

[0021] Figure 11 This is a diagram illustrating an example of the functional structure of an SN. Detailed Implementation

[0022] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. Furthermore, the embodiments described below do not limit the invention to which the technical solution pertains, and not all combinations of features described in the embodiments are necessary for the invention. Two or more features from the plurality of features described in the embodiments can be arbitrarily combined. Additionally, identical or identical components are labeled with the same reference numerals, and repeated descriptions are omitted.

[0023] exist Figure 1This embodiment illustrates a configuration example of a wireless communication system. This wireless communication system is, for example, a cellular communication system based on a cellular communication standard such as the fifth-generation (5G) standard defined by the 3rd Generation Partnership Project (3GPP). Furthermore, this is an example; the following discussion can be applied to any system in which the terminal device can continue communication while switching the cell to its destination.

[0024] exist Figure 1 In the wireless communication system, the base station provides wireless communication services to the terminal device 151. The terminal device 151 can connect to two or more cells in parallel. Among these two or more cells, the cell that controls the communication of the terminal device 151 is called the primary cell, and the cell connected to the terminal device 151 under the control of the base station (master node: MN100) of the primary cell is called the secondary cell. Furthermore, in this embodiment, for simplicity, it is assumed that the terminal device 151 is connected to MN100 and additionally connected to the secondary cell. Figure 1 In the example shown, the following example is provided: two base station devices (secondary nodes: SN101 and SN102) provide candidate cells to become the connection destination of the secondary cell of terminal device 151.

[0025] A base station device can be composed of a centralized unit (CU) and a distributed unit (DU). A DU, for example, includes an antenna and signal processing functions for radio frequencies, and serves as an interface for receiving and transmitting radio signals between itself and a terminal device. Each DU forms at least one cell. On the other hand, a CU is configured to accommodate one or more DUs and performs control over communications conducted through these DUs. For example, the CU generates configuration information for when a terminal device connects to each DU and notifies the terminal device of this information. Furthermore, in Figure 1 In the example, SN101 functions as a CU, providing access to cells 131 to 133 via DU111 to DU113 respectively. Similarly, SN102 also functions as a CU, providing access to cells 141 to 143 via DU121 to DU123 respectively. Terminal device 151 is configured to connect to at least one of these cells, receiving and transmitting radio signals in the cell at its connection destination, thereby receiving wireless communication services. Furthermore, terminal device 151 connects to a base station device constituting the cell containing the location where terminal device 151 is located; hereinafter, this will be referred to as "connection to a cell (provided by its base station device)".

[0026] In this embodiment, the terminal device 151 performs pre-settings for adding or changing a secondary cell, for example, based on whether a connection with the primary cell has been established, or based on a certain degree of degradation in the radio quality of the secondary cell in the connection. The state where these pre-settings have been performed is as follows: the parameters for connecting the terminal device 151 to a candidate cell of the connection destination have been set, but on the other hand, the terminal device 151 has not actually established a connection to that cell. The pre-settings include conditions for cell connections such as changes or additions to the cell for the connection destination. When it is determined that these conditions are met, the terminal device 151 synchronously attempts to establish a connection in the new connection destination cell. Furthermore, when changing the secondary cell of the connection destination, the terminal device 151 performs a disconnection process from the secondary cell of the connection source. The process by which the terminal device 151 autonomously performs a handover or addition of a secondary cell based on the determination that the conditions are met using such pre-settings is called Conditional Secondary Cell Addition or Change (CPAC). Furthermore, the process by which the terminal device 151 autonomously switches the primary cell of the connection destination based on the determination that the conditions are met is called Conditional Handover (CHO). Furthermore, the following implementation is described with reference to CPAC, but it can also be applied to CHO. That is, by changing the conditions of CPAC to the conditions of CHO, and the presets used for CPAC to the presets used for CHO, the following discussion can be applied to CHO. In addition, the types of messages may differ in CHO and CPAC, but those skilled in the art can appropriately substitute them with suitable messages.

[0027] In the case of CPAC, the connected MN100 sends a subcell addition request message (SgNB Addition Request) to other base station devices that provide candidate subcells as destinations for addition or change. Alternatively, this subcell addition request can be initiated, for example, by receiving a predetermined message (e.g., SgNB Change Required) from the base station device providing the subcell currently connected to terminal device 151 to the connected MN100. In this case, MN100 can send the subcell addition request as described above based on receiving its predetermined message. Then, the other base station device (hereinafter, sometimes referred to as the "candidate base station") that provides candidate subcells as destinations for addition or change sends a response message (SgNB Addition Request Acknowledge) to MN100 containing information such as communication parameters that terminal device 151 should use when adding or changing subcells. Here, the candidate base station retains the communication parameters and other information it sends as pre-set information. Additionally, the MN100 or candidate base station determines the conditions that must be met when adding or changing its secondary cell. Then, the MN100 notifies the terminal device 151 of pre-defined information including: information on the communication parameters to be used when adding or changing a secondary cell using a cell provided by the candidate base station as a secondary cell, and the conditions for establishing such a connection. This notification can, for example, be made using a Radio Resource Control (RRC) message. In one example, the pre-defined information is notified to the terminal device 151 via an RRC Reconfiguration message.

[0028] Here, the pre-configured information may consist of reference configuration information (reference configuration) that serves as a baseline, and incremental configuration information (incremental configuration) that differentiates the configuration information of each candidate sub-cell from its reference configuration. The reference configuration is configuration information shared by multiple cells, while the incremental configuration is information related to portions of the configuration information in each cell that differ from the reference configuration. That is, the incremental configuration is configuration information inherent in each cell. If both the reference configuration and the incremental configuration are received, the terminal device 151 uses the configuration values ​​for the configuration items included in the incremental configuration. On the other hand, the terminal device 151 uses the configuration values ​​specified in the reference configuration for configuration items not included in the incremental configuration. Furthermore, the terminal device 151 uses the configuration values ​​of the reference configuration for configuration items that are specified as needing to be maintained in the reference configuration (designated as "NeedM") but not for other configuration items. Additionally, MN100 notifies terminal device 151 of information for determining which of the following decisions to make: For setting items not included in the incremental configuration, but specified in the reference configuration as requiring only one action related to the setting item (designated as "Need N"), will terminal device 151 perform the action related to the setting item only once based on the setting value of the reference configuration, or will it interpret this as eliminating the setting value of the reference configuration and not performing the action related to the setting item? Alternatively, in this case, MN100 and terminal device 151 may be pre-set to consistently perform either action without requiring notification of such information. By using such a combination of reference configuration and incremental configuration, the amount of setting information data notified to terminal device 151 can be reduced. That is, the configuration information shared across N cells is notified to the terminal device 151 only once per cell as a reference configuration, while the configuration information inherent in each cell is notified to the terminal device 151 incrementally per cell. Thus, the portion of the configuration information corresponding to the reference configuration in the configuration information for (N-1) cells is omitted, thereby reducing the amount of configuration information data notified. Furthermore, MN100 can use the configuration information of one of the multiple candidate cells as the reference configuration, or the configuration information of the serving cell used for current communication (any one of the multiple cells used as the serving cell if multiple cells are used as the serving cell), or the configuration information of cells other than candidate cells and serving cells as the reference configuration. In this case, MN100 can notify the terminal device 151 of information for determining which cell's configuration information to use as the reference configuration.As an example, when using the configuration information of one of the multiple serving cells (or candidate cells) as a reference configuration, the MN100 can efficiently specify the configuration information to be used as the reference configuration using existing identification information such as CellGroupId (cell group identifier), SCellIndex (sub-cell index), and condReconfigId (conditional reconfiguration identifier) ​​inherently assigned in the configuration information.

[0029] As mentioned above, incremental configuration consists of setting items in the setting information of each cell that contain setting values ​​different from the reference configuration. Therefore, the smaller the difference between the setting information of each cell and the reference configuration, the fewer the number of setting items included in the incremental configuration, and the smaller the overall data volume of the incremental configuration. On the other hand, if the setting information of each cell deviates significantly from the reference configuration, the number of setting items included in the incremental configuration increases, and its data volume also increases. Depending on the situation, almost all the setting items in the reference configuration may be replaced by the setting items in the incremental configuration, which may also increase the overall data volume of the setting information.

[0030] In this embodiment, given this situation, multiple reference configurations can be set, and the terminal device 151 is notified of these multiple reference configurations. Furthermore, information indicating which of these multiple reference configurations is used as the basis for the incremental configuration of each candidate cell is also notified. For example, MN100 notifies the terminal device 151 of information in the following form.

[0031] First reference configuration (reference configuration ID=1) Second reference configuration (reference configuration ID=2) Information for Community 131 (First Incremental Configuration, Reference Configuration ID=1) Information for cell 132 (second incremental configuration, reference configuration ID=1)

[0032] Information for Community 142 (Fifth Incremental Configuration, Reference Configuration ID=2) Information for Community 143 (Sixth Incremental Configuration, Reference Configuration ID=2) Here, the reference configuration ID is identification information that uniquely identifies a reference configuration. Among this information, the information of the first and second reference configurations is notified to the terminal device 151 as information elements such as ReferenceConfigAddModlist (reference configuration add / modify list). Additionally, the incremental configuration information inherent in each cell is notified to the terminal device 151 as CondReconfigToAddMod (conditional reconfiguration add / modify) information elements. The CondReconfigToAddMod information element is prepared, for example, for each candidate cell. The CondReconfigToAddMod information element includes identification information (condReconfigId) inherent in its information elements, a cell identifier for each cell, the reference configuration ID, the conditions for CPAC to be performed, and information about the incremental configuration of the cell. Furthermore, CPAC refers to the addition and modification of sub-cells with conditions, but different conditions can be prepared for the addition and modification of sub-cells. Terminal device 151 can, for example, extract a first reference configuration from information received related to cell 131 using information with reference configuration ID=1, and generate configuration information for cell 131 based on this first reference configuration and a first incremental configuration. Similarly, terminal device 151 can generate configuration information for cell 143 using a second reference configuration and a sixth incremental configuration. With this configuration, for example, even if the configuration information used for connection between cells 131, 132, and 143 differs significantly, the disadvantage of using a shared reference configuration can be eliminated. Furthermore, in any cell, the reference configuration itself can be used as its own configuration information. In other words, the configuration information of any cell can be used as a reference configuration. For example, the configuration information of cell 131 can be used as the first reference configuration and / or the configuration information of cell 143 can be used as the second reference configuration. In this case, for example, MN100 can notify terminal device 151 of information in the following form.

[0033] First reference configuration (Cell 131, Reference Configuration ID=1) Second reference configuration (Cell 143, Reference Configuration ID=2) Information for cell 132 (second incremental configuration, reference configuration ID=1)

[0034] Information for Community 142 (Fifth Incremental Configuration, Reference Configuration ID=2) Furthermore, this is just one example; it could also be that, within the scope of the configuration information for each cell that the terminal device 151 can construct, other forms of information are notified to the terminal device 151. In addition, the configuration information for each cell includes not only communication parameters but also CPAC conditions (condExecutionCond (condition for execution), conditions for adding / changing cells, and an identifier for specifying additionally defined execution conditions).

[0035] In one example, different reference configurations can be used for each SN, or a shared reference configuration can be used for multiple SNs, with other reference configurations used for more than one other SN. Alternatively, multiple reference configurations can be used within a single SN. The group of cells using such a shared reference configuration can be determined, for example, by MN100 connected to terminal device 151, or by the SN. Furthermore, the group of cells using such a shared reference configuration can be determined between MN100 and SN101 and SN102. Alternatively, the group using the shared reference configuration can be predetermined.

[0036] Next, we will illustrate the decision-making process for reference configurations and incremental configurations with a few examples.

[0037] First, as a first example, the case where MN100 determines a reference configuration will be explained. When determining a reference configuration, MN100 notifies the SN of the cell that provides the reference configuration. The SN determines the incremental configuration of its cell by the difference between the setting information of each cell provided by this device and the notified reference configuration. Alternatively, the SN may refuse to use the notified reference configuration. In this case, the SN may notify MN100 of other reference configurations used instead of the notified reference configuration, and incremental configurations generated based on those other reference configurations. Furthermore, MN100 may also notify the SN of the identification information (reference configuration ID) of the reference configuration that notified the SN, and more than one identification information that can be assigned to other reference configurations if the use of its reference configuration is refused. In this case, the SN may, for example, notify MN100 of the identification information assigned to those other reference configurations when notifying MN100 of the aforementioned other reference configurations.

[0038] For example, such as Figure 2As shown, MN100 includes the first reference configuration (Reference config #1) in the SgNBaddition request and sends it to SN101 (S201). SN101 can accept the use of the first reference configuration, notify its subordinate DUs (DU111~DU113) of the first reference configuration, and generate incremental configurations (S202). Each DU prepares configuration information for the connection of UE151 to this device and notifies SN101 of the difference between its configuration information and the first reference configuration, i.e., the incremental configuration (S205). In addition, SN101 can request each DU to notify the configuration information for the connection of UE151, and the DU notifies SN101 of the configuration information. In this case, SN101 can generate incremental configurations related to each DU based on the first reference configuration and the notified configuration information. SN101 can notify MN100 of its incremental configuration information when obtaining the incremental configurations of each DU (S207). In addition, SN101 can also notify MN100 that it is using the first reference configuration notified from MN100. Furthermore, notifications from the SN to the MN100 can be made using information elements from the SgNB addition request ACK, for example. Notifications can be made via the CG-CandidateList. Alternatively, newly defined information elements other than those in the CG-CandidateList can be used. This information exchange can also be performed using any message that can be used in information exchange based on the Xn interface between the MN100 and the SN.

[0039] On the other hand, MN100 includes the second reference configuration (Reference config #2) in the SgNB addition request and sends it to SN102 (S203). SN102 may refuse to use the second reference configuration and notify its subordinate DUs (DU121~DU123) of the third reference configuration, generating an incremental configuration (S204). Each DU prepares configuration information for UE151 to connect to this device and notifies SN102 of the difference between its configuration information and the third reference configuration, i.e., the incremental configuration (S206). In this case, similarly to the above, each DU may notify SN102 of the configuration information itself, and SN102 may use the third reference configuration to generate the incremental configuration. SN102 may notify MN100 of its incremental configuration information when obtaining information about the incremental configuration of each DU (S208). Furthermore, in this case, SN102 notifies MN100 of the third reference configuration used instead of the second reference configuration.

[0040] Furthermore, the reception and transmission of information between the CU and DU of the SN can be performed using information elements (IEs) associated with the CPAC, included in UE context setup request, UE context setup request response, UE context release request, UE context release command, UE context release complete, UE context modification request, or UE context modification response. Additionally, new IEs for communication settings using the reference configuration can be prepared in existing F1 interface messages, and new F1 interface messages can also be prepared. This is also true in the following description. Furthermore, information from the CU to the DU can be communicated using the CU to DU RRC information element, and information from the DU to the CU can be communicated using the DU to CURRC information element. Furthermore, when multiple cells are formed in a DU, information specifying which cell the information to be received and transmitted between the DU and CU relates to can be received and transmitted simultaneously.

[0041] When MN100 obtains the incremental configuration of each cell that is a candidate cell to become a secondary cell, as described above, it notifies UE151 of its incremental configuration and reference configuration information (S209). Figure 2 In the example, UE151 is notified of the first reference configuration related to the configuration information of the cells subordinate to SN101, the third reference configuration related to the configuration information of the cells subordinate to SN102, and the incremental configurations of each cell. Here, as described above, each incremental configuration is notified to UE151 along with information indicating which reference configuration it is associated with (reference configuration ID). Figure 2 In the example, UE151 is notified that the incremental configurations of DU111~DU113 are associated with the first reference configuration, and the incremental configurations of DU121~DU123 are associated with the third reference configuration.

[0042] Next, as a second example, we will illustrate how the SN determines the reference configuration. For example... Figure 3As shown, MN100 sends an SgNB addition request to SN101 and SN102. MN100 can notify the SNs of the reference configuration and incremental configuration that should be generated in this SgNB addition request. Additionally, MN100 can notify each SN of the available reference configuration IDs. This allows the maximum number of reference configurations that can be set in the SN to be specified. Figure 3 In the example, reference configuration IDs 1 and 2 are notified to SN101 (S301), and reference configuration IDs 3 and 4 are notified to SN102 (S304). Furthermore, in Figure 3 In this example, to ensure consistency in understanding the reference configuration ID between MN100 and SN, and to prevent duplication of reference configuration IDs used in each SN, the reference configuration ID is notified from MN100. However, this is just an example; the same ID can also be set in multiple SNs. For example, the reference configuration ID can be specified by combining the identification information representing the SN with its ID. That is, the reference configuration with reference configuration ID=1 for SN101 and the reference configuration configuration with reference configuration ID=1 for SN102 can be different configurations. Furthermore, in this case, the following information is notified from MN100 to terminal device 151 (S310).

[0043] Reference configuration for SN=101 First reference configuration (reference configuration ID=1) Second reference configuration (reference configuration ID=2) Reference configuration for SN=102 Third reference configuration (Reference configuration ID=1) Incremental configuration of SN=101 Information for Community 131 (First Incremental Configuration, Reference Configuration ID=1) Information for cell 132 (second incremental configuration, reference configuration ID=1) Information for Community 133 (Third Incremental Configuration, Reference Configuration ID=2) Incremental configuration of SN=102 Information for Community 141 (Fourth Incremental Configuration, Reference Configuration ID=1) Information for Community 142 (Fifth Incremental Configuration, Reference Configuration ID=1) Information for Community 143 (Sixth Incremental Configuration, Reference Configuration ID=1) For example, when acquiring the configuration information of cell 132, terminal device 151 extracts a first reference configuration based on SN=101 and reference configuration ID=1. Then, terminal device 151 can use its first reference configuration and second incremental configuration to acquire the configuration information of cell 132. On the other hand, when acquiring the configuration information of cell 143, terminal device 151 extracts a third reference configuration based on SN=102 and reference configuration ID=1. Then, terminal device 151 can use its third reference configuration and sixth incremental configuration to acquire the configuration information of cell 143. Furthermore, in the above example, an example of determining a reference configuration by combining the identification information of each SN and the reference configuration ID has been described, but it is not limited to this. For example, more generally, cell groups can be defined, and a reference configuration can be determined based on the identification information of the cell group and the reference configuration ID. Here, a cell group can be multiple cells subordinate to multiple SNs. Here, cells subordinate to an SN can belong to one group, or more than one cell subordinate to an SN can belong to a first group, and other cells subordinate to that SN can belong to a second group. In this configuration, if only the reference configuration ID is used, two or more reference configurations set in two or more groups can be identified. However, by combining the reference configuration ID with the group identification information, a single reference configuration can be uniquely identified.

[0044] Furthermore, the maximum number of SNs providing candidate cells can be specified in the MN100. In this case, if configuration information related to cells provided by more than the maximum number of SNs should be set, the MN100 can instruct the SNs not to use reference configuration and incremental configuration for SNs exceeding their maximum number, but to directly use the normal configuration information (full configuration). In this case, the SN can be instructed not to provide incremental configuration for subordinate DUs, but to provide full configuration for subordinate DUs.

[0045] Furthermore, where duplicate reference configuration IDs are permitted across multiple SNs (or groups of cells), for example, each SN can be notified of a value indicating the maximum number of reference configurations that can be set within its SN. Alternatively, based on a reference configuration ID used in multiple SNs as described above, a value indicating the maximum number of reference configurations that can be set within each SN can be notified. As an example, MN100 can maintain the maximum number of reference configurations that can be set within terminal device 151, and determine the number of reference configurations that can be further set within terminal device 151 based on the number of reference configurations currently set (notification completed) and its maximum number. Then, MN100 can determine the maximum number to be notified to each SN based on this number. Alternatively, MN100 may not notify the SNs of the maximum number or reference configuration ID, but only notify the SNs that reference configurations and incremental configurations should be generated. For example, if the maximum number of reference configurations is predetermined in the SN, only the notification of the need to generate reference configurations and incremental configurations is required.

[0046] Each SN sets a reference configuration within the maximum number of possible reference configurations. Then, the SN can instruct its subordinate DUs to generate incremental configurations by notifying them of their respective reference configurations (S302, S303, S305). Each DU generates an incremental configuration based on the notified reference configuration and notifies the SN of the generated incremental configuration (S306, S307). The SN aggregates the incremental configurations generated in each DU and notifies MN100 of all the set reference configurations and incremental configurations (S308, S309). Furthermore, the incremental configuration, along with information indicating which reference configuration it is associated with, is notified to MN100. For example, SN101 may notify MN100 that the incremental configurations of DU111 and DU112 are associated with the reference configuration ID=1, and the incremental configuration of DU113 is associated with the reference configuration ID=2. Furthermore, the above example illustrates an instance where the SN generates a reference configuration and notifies the DUs of the generated reference configuration, and the DUs generate incremental configurations, but this is not an exception. For example, the SN can also request the DU to provide configuration information that should be notified to the terminal device 151, summarize the configuration information, and generate a reference configuration based on this configuration information. For example, the SN can generate a reference configuration with the minimum total data size of the incremental configuration and the reference configuration from a reference configuration shared by multiple configuration information.

[0047] Furthermore, the SN does not need to use up all of the notified reference configuration IDs. Figure 3In the example, SN102 can use reference configurations ID=3 and 4, but it can also use only one reference configuration (reference configuration ID=3) to generate incremental configurations DU121~DU123 based on that reference configuration. Then, SN102 notifies MN100 of the association between these incremental configurations and all, and all, the reference configurations of the reference configuration with reference configuration ID=3. Afterwards, MN100 notifies terminal device 151 of the acquired reference configurations and incremental configurations, as well as information indicating which reference configuration each incremental configuration is associated with.

[0048] As a third example, in the absence of a reference configuration, the MN100 can instruct the SN to generate both a reference configuration and an incremental configuration. With a reference configuration, the MN100 can notify the SN of its reference configuration and instruct the SN to generate an incremental configuration. For example, as... Figure 4 As shown, during the period when there is no reference configuration, MN100 instructs SN, i.e., SN101, to generate a reference configuration and an incremental configuration (S401). Then, SN101 can, for example, generate a reference configuration within the device itself, and instruct DU111~DU113 to generate incremental configurations (S402). Furthermore, in Figure 4 The example illustrates an instance where SN101 generates a reference configuration and notifies DU111-113 of the generated reference configuration, and DU111-113 generates incremental configurations, but is not limited to this. For example, SN101 may also request DU111-113 to provide configuration information that should be notified to terminal device 151, and aggregate the configuration information to generate a reference configuration. In either case, SN101 notifies MN100 of the acquired reference configuration and the incremental configuration used for each DU to form a cell (S403, S404).

[0049] Subsequently, MN100 instructs SN102 to generate an incremental configuration (S405). In this case, MN100 has a reference configuration notified from SN101, and therefore can notify SN102 of its reference configuration, instructing the generation of the incremental configuration. SN102 may accept or reject the use of this reference configuration. Figure 4In this example, SN102 is set to reject the use of the reference configuration and decide to use another reference configuration. In this case, SN102 notifies DU121-DU123 of the other reference configuration (S406), and DU121-DU123 generate incremental configurations based on the other reference configurations. Then, SN102 can collect incremental configurations from DU121-DU123 (S407) and notify MN100 of its incremental configurations (S408). Furthermore, SN102 can, for example, collect setting information from DU121-DU123 respectively, and generate candidate incremental configurations by comparing the setting information with the reference configurations notified from MN100. Then, SN102 can generate other reference configurations if the amount of data for its incremental configurations exceeds a predetermined value. Furthermore, this is just an example; the basis for SN102 to generate other reference configurations can be arbitrarily defined. MN100 notifies the terminal device 151 of the maintained reference configuration and the collected incremental configurations (S409).

[0050] Ended as described above Figure 4 After processing, MN100 maintains the first reference configuration used in SN101 and the second reference configuration used in SN102. Subsequently, if further pre-configuration is made to allow other cells to be candidates for secondary cells, MN100 can notify the SN of the first and second reference configurations and instruct the generation of an incremental configuration. In this way, MN100 can notify the SN of the entire reference configuration being maintained and instruct the generation of the incremental configuration. However, this is just one example; MN100 may also, for instance, notify the SN of only a portion of the reference configuration being maintained and instruct the generation of the incremental configuration.

[0051] As described above, terminal device 151 can acquire reference configurations and incremental configurations for multiple cells that are added as secondary cells or become candidates for changing destinations. MN100 can send instructions to terminal device 151 to enable only a portion of these multiple cells. For example, MN100 can, as terminal device 151 moves, pre-set the activation of cells within a predetermined distance of terminal device 151 and pre-set the deactivation of other cells. Terminal device 151 can, for example, reproduce and maintain the setting information using the reference configuration and incremental configuration for the pre-set activated cells. Furthermore, terminal device 151 can perform radio quality measurements for activated cells, but not for deactivated cells. MN100 can, for example, use the identification information (condReconfigId) inherent to the information elements related to each cell to specify the cells to be activated / deactivated. Furthermore, when multiple cells using a shared reference configuration are activated / deactivated together, a reference configuration ID of their reference configuration can also be specified. For example, information such as the following can be notified to terminal device 151.

[0052] Reference configuration ID=1: Invalid Reference configuration ID=2: Partially valid condReconfigId=A: Valid condReconfigId=B: Invalid Reference configuration ID=3: All valid Furthermore, in the examples above, when a portion of the reference configuration is enabled, information indicating whether it is enabled or invalid is specified for each incremental configuration using the reference configuration; when the entire reference configuration is enabled, all incremental configurations using the reference configuration are enabled. However, this is not a limitation. It is also possible to set the reference configuration to "enabled" in both the case of enabling only a portion of the incremental configurations using the reference configuration and the case of enabling all of them, in which case the incremental configurations using the reference configuration are always displayed as enabled / invalid independently.

[0053] Terminal device 151 measures the radio quality of the (activated) cell of the target cell. Based on the determination that a specific cell meets the conditions for addition / modification as a secondary cell, it notifies MN100 of an RRC ReconfigurationComplete message and accesses the specific cell. That is, terminal device 151 can perform random access steps for accessing its specific cell.

[0054] Furthermore, after the addition or change of a secondary cell, the terminal device 151 maintains the setting information related to the candidate cell. However, it is conceivable, for example, that if the terminal device 151 moves away from its candidate cell, the setting information should be deleted. Additionally, it is conceivable, for example, that after the reference configuration and incremental configuration are notified to the terminal device 151, at least one of the reference configuration and incremental configuration needs to be changed due to the passage of a certain period of time. Such deletion or change of settings is performed, for example, through an instruction from MN100.

[0055] The MN100 or SN connected to the terminal device 151 can, for example, decide to delete the reference configuration set in the terminal device 151 based on changes or additions to the sub-cell candidate, or based on the setting of new communication parameters based on the reference configuration and incremental configuration. Hereinafter, the MN100 or SN connected to the terminal device 151 will sometimes be referred to as the "network". Alternatively, a network node other than the MN100 or SN may decide to delete the reference configuration set in the terminal device 151 and send its deletion instruction to the terminal device 151 via the MN100 or SN.

[0056] For example, the network can decide which reference configuration to delete based on whether the number of set reference configurations reaches its maximum (exceeding the maximum number). The network can, for example, send an instruction to terminal device 151 to delete the oldest reference configuration. Alternatively, the network can decide which reference configuration to delete based on the measurement results of the radio quality in terminal device 151. For example, the network can determine the maximum radio quality of the cells using multiple reference configurations and decide to delete the reference configuration with the lowest maximum value (or one not used in cells where the radio quality can be determined to be good). Furthermore, the network can, for example, sequentially delete incremental configurations for cells more than a predetermined distance from the location of terminal device 151 as terminal device 151 moves, and decide to delete the specific reference configuration if all incremental configurations referencing a specific reference configuration have been deleted. Alternatively, the network can instruct terminal device 151, which sets the reference configuration, to delete the reference configuration, allowing terminal device 151 to select which reference configuration to delete. In this case, terminal device 151 can select and delete the reference configuration and notify the network of the reference configuration ID of the deleted reference configuration.

[0057] The network removes cells from the candidate sub-cells of terminal device 151 that use the deleted reference configuration to generate incremental configurations. For example, MN100 sends an SgNB ReleaseRequest to a subordinate SN that uses the deleted reference configuration and instructs the SN to delete the configuration information related to its cell. Furthermore, if a specific reference configuration is deleted and the incremental configuration referring to that specific reference configuration is maintained, its incremental configuration is also completely deleted. Additionally, cells corresponding to their incremental configurations are removed from the candidate sub-cells. Alternatively, if a specific reference configuration is deleted and the incremental configuration referring to that specific reference configuration is maintained, its incremental configuration may be reconstructed based on another reference configuration. In this case, MN100 specifies another reference configuration and instructs the SN that has a subordinate cell using its incremental configuration to update its incremental configuration. Furthermore, in this case, the SN may be forced to use another reference configuration. That is, the SN may not be allowed to refuse the use of other reference configurations. For example, in an SN using reference configurations ID=1 and 2, the deletion of the reference configuration ID=2 is considered a decision. In this case, MN100 can instruct its SN to reconstruct an incremental configuration based on reference configuration ID2 using the reference configuration with reference configuration ID=1. Furthermore, it can be ensured that the reference configuration used in any cell is not deleted.

[0058] Alternatively, even if the secondary cell is no longer in use and the primary cell is handed over, the terminal device 151 may not delete the reference configuration and incremental configuration unless there is an explicit instruction from MN100. However, this is not a limitation. For example, the reference configuration generated in the handover source MN100 may be deleted. On the other hand, the reference configuration generated in the SN may not be deleted. Furthermore, in this case, the handover source MN100 may notify the handover destination MN100 of the contents of the reference configuration corresponding to the reference configuration ID, the SN that generated its reference configuration, and information about the candidate cells of the secondary cell. In addition, the handover source MN100 may notify the handover destination MN100 of the incremental configuration (incremental configuration ID, incremental configuration contents, and conditions for adding / changing the cell corresponding to its incremental configuration) based on its reference configuration. Thus, it is not necessary to perform the setting process for adding / changing the secondary cell again in the handover destination MN100. Furthermore, in cases where the use of the secondary cell is stopped, the primary cell is handed over, or the use of the primary cell is suspended or interrupted (when the RRC state changes from connected mode to idle mode or inactive mode), the terminal device 151 can automatically delete the reference configuration and incremental configuration, or either of them, without waiting for explicit instructions from MN100. In this case, there is no need to reduce the dynamic memory used to maintain the network-side reference configuration, or to share the reference configuration and incremental configuration with other base station devices, thus simplifying the actual installation on the network side.

[0059] When the reference configuration changes, an "incremental reference configuration" can be used, representing only the settings that should be changed in the reference configuration. For settings set in the incremental reference configuration, the reference configuration can be changed by their values; for other settings, the reference configuration can be maintained. Sometimes, the incremental configuration also changes due to a change in the reference configuration. Therefore, an "incremental incremental configuration" can also be used, representing only the settings that should be changed in the incremental configuration. For settings set in the incremental incremental configuration, the incremental configuration can be changed by their values; for other settings, the incremental configuration can be maintained. In this way, when the reference configuration (and incremental configuration) changes, only the difference values ​​are exchanged between MN100, SN, and the terminal device, thus allowing for updates to the setting information with a smaller amount of data. Furthermore, in the event of a significant change in the reference configuration or incremental configuration, the reference configuration and incremental configuration currently in use can be replaced with a newly generated reference configuration and incremental configuration without using the incremental reference configuration or incremental incremental configuration. That is, the reference configuration and incremental configuration currently in use are deleted, and the newly generated reference configuration and incremental configuration are stored in the terminal device 151.

[0060] When the reference configuration is changed, the network notifies the terminal device 151 of either (1) the incremental reference configuration or (2) the newly generated reference configuration. Upon receiving the incremental reference configuration, the terminal device 151 replaces the settings specified by the incremental reference configuration in the settings of the currently used reference configuration with the settings of its incremental reference configuration. In addition, upon receiving the newly generated reference configuration, the terminal device 151 replaces the entire reference configuration that is being maintained with the newly generated reference configuration. Furthermore, if there are changes in the settings specified by the incremental configuration that are not related to each cell using its reference configuration, the terminal device 151 changes its settings related to that cell and updates the setting information. In this configuration, even if the reference configuration is changed, there may be situations where the setting information related to each cell is not updated due to the incremental configuration. However, the terminal device 151 maintains the updated reference configuration for use in the generation of setting information for incremental configurations of other cells after use. In addition, when the reference configuration is updated, the reference configuration of the object to be updated can be specified using the reference configuration ID. In addition, the updated reference configuration can inherit the reference configuration ID of the previous reference configuration, or a new reference configuration ID can be assigned to the updated reference configuration.

[0061] On the other hand, when changing the incremental configuration, the network notifies the terminal device 151 of either (1) the incremental configuration or (2) the newly generated incremental configuration. Upon receiving an incremental configuration related to a specific cell, the terminal device 151 replaces the settings specified by the incremental configuration in the current incremental configuration for its cell with the settings of its incremental configuration. Furthermore, upon receiving a newly generated incremental configuration for a specific cell, the terminal device 151 replaces the entire incremental configuration of its currently maintained cell with the newly generated incremental configuration. Additionally, when updating the incremental configuration, the incremental configuration of the updated target can be specified by the cell identifier and condReconfigId. The terminal device 151 updates the configuration information of the cell using its incremental configuration along with the change in the incremental configuration. The terminal device 151 updates the configuration information by changing the updated incremental configuration settings in the configuration information of the cell corresponding to the updated incremental configuration along with the update of its incremental configuration.

[0062] Alternatively, when the terminal device 151 is notified of an incremental reference configuration for the existing first reference configuration and an instruction is sent to generate a second reference configuration, the network instructs that the first reference configuration be maintained as is. For example, if some cells among a plurality of cells using the first reference configuration use the second reference configuration as a reference configuration, and other cells use the first reference configuration as a reference configuration, a new second reference configuration based on the existing first reference configuration is generated, and the first reference configuration is maintained. Furthermore, in this case, a new reference configuration ID can be assigned to the second reference configuration, and the terminal device 151 is notified of the reference configuration ID. Furthermore, if the MN100 determines a change in the reference configuration, the MN100 can instruct the SN using its reference configuration to change the reference configuration in the same way as the notification to the terminal device 151. Additionally, if the SN determines a change in the reference configuration, the SN designates a reference configuration for the MN100 and requests a change; if the request is granted, the reference configuration can be changed. In this case, if the change in the reference configuration is granted, the MN100 notifies the SN of the permission information and also notifies the terminal device 151 of the granted reference configuration.

[0063] Furthermore, the above explanation details the handling of situations where either the reference configuration or the incremental configuration is updated, for example... Figure 5As shown, both the reference configuration and the incremental configuration can be updated. That is, it is determined which of the reference configuration and the incremental configuration should be updated (S501, S503). Then, if the reference configuration should be updated (yes in S501), the incremental reference configuration or the newly prepared reference configuration is provided to the terminal device (and the SN as needed) (S502). Similarly, if the incremental configuration should be updated (yes in S503), the incremental incremental configuration or the newly prepared incremental configuration is provided to the terminal device (and the SN as needed) (S504).

[0064] Furthermore, the terminal device 151 can generate configuration information for each cell based on the acquired reference configuration and incremental configuration, but it needs to verify whether the configuration information is appropriate. For example, if the configuration information contains parameters that exceed the capabilities of the device (i.e., the terminal device 151 cannot execute), the terminal device 151 can determine that the configuration information is inappropriate. Additionally, the terminal device 151 can also determine that the configuration information is inappropriate if the configuration information does not contain necessary parameters or if the terminal device 151 cannot interpret the content of the configuration information. For example, if the reference configuration is mistakenly deleted, the incremental configuration alone may not contain the necessary parameters, thus determining that the configuration information is inappropriate.

[0065] For example, such as Figure 6As shown, terminal device 151 can obtain reference configuration and incremental configuration for a candidate secondary cell at the time point (S601), use this information to generate configuration information for its cell (S602), and determine whether its configuration information is appropriate (S603). That is, terminal device 151 determines whether its configuration information can be used for a cell that has become an environment where configuration information can be prepared (reference configuration and incremental configuration are complete). Then, if the configuration information generated by combining the reference configuration and incremental configuration is appropriate, terminal device 151 maintains its configuration information. On the other hand, if its configuration information is inappropriate, terminal device 151 notifies the network (MN100 or SN in the connection) of the reference configuration ID and the identification information (condReconfigId) of the incremental configuration (S604). This notification is, for example, via an RRC Reconfiguration Complete message. Here, information indicating that an error has occurred is notified to the network. This notification can be, for example, by setting the failuretype in the message to srb3-integrityFailure or scg-reconfigFailure. Upon receiving the notification, the network, based on the reference configuration ID and the incremental configuration identification information, notifies the terminal device 151 of the reference configuration, incremental configuration, and reference configuration ID. Furthermore, the terminal device 151 can also notify the network which part of the reference configuration or the incremental configuration is inappropriate, and which is the reason for the inappropriateness. Additionally, if parameters that the terminal device 151 cannot use are configured, the network can instruct the SN to reconfigure the reference configuration and incremental configuration. Accordingly, the terminal device 151 can determine the appropriateness of the configuration information before actually adding / changing sub-cells and prepare appropriate configuration information in advance.

[0066] In addition, such as Figure 7As shown, terminal device 151 may also not generate configuration information at the time when it obtains the reference configuration and incremental configuration. For example, it may generate configuration information for cells whose wireless quality measurement results meet predetermined conditions (S701, S702). In this case, terminal device 151 checks the appropriateness of the generated configuration information (S703). If it is determined that the generated configuration information is inappropriate, terminal device 151 may then generate configuration information for other cells whose wireless quality measurement results meet predetermined conditions. Furthermore, even if there is no secondary cell whose wireless quality measurement results meet predetermined conditions, if there are other cells with better wireless quality than the current secondary cell, and the configuration information in those cells is appropriate, terminal device 151 may switch the connection to those cells. In the case of inappropriate configuration information, terminal device 151 may notify the network regarding the inappropriate configuration information as described above (S704). In one example, after connecting to a cell with appropriate configuration information, terminal device 151 can use UE assistance information to notify the network of the reference configuration ID and incremental configuration identification information (condReconfigId) corresponding to its inappropriate configuration information. Upon receiving this notification, the network corrects its reference configuration and incremental configuration based on the reference configuration ID and incremental configuration identification information, and then notifies terminal device 151 of the reference configuration, incremental configuration, and reference configuration ID again. In this way, configuration information is not generated at the time the reference configuration and incremental configuration are acquired, but rather generated based on predetermined conditions such as meeting radio quality requirements, and its appropriateness is evaluated. This reduces the memory capacity required to store the configuration information in terminal device 151.

[0067] Furthermore, when using the serving cell's configuration information as a reference configuration, the serving cell's configuration information may change from the time the reference configuration and incremental configuration are acquired until the time when the measurement result of the wireless quality of any candidate cell meets predetermined conditions. In this case, the reference configuration is also changed, so the generated configuration information may differ depending on whether the cell's configuration information is generated using this information at the time the reference configuration and incremental configuration are acquired, or when the cell's configuration information is generated at the time when the measurement result of the candidate cell's wireless quality meets predetermined conditions. Therefore, it is necessary to reach an agreement between the network and the terminal device 151 on the time at which the cell's configuration information is generated. Therefore, the network can also notify the terminal device 151 of the information specifying when to generate the cell's configuration information. Alternatively, the network and the terminal device 151 can be pre-configured to not notify the network of this information, but to generate the cell's configuration information at any pre-set fixed time.

[0068] When using the serving cell's configuration information as a reference configuration, the terminal device 151 can save the serving cell's configuration information as a reference configuration at the time it acquires the reference configuration and incremental configuration. Alternatively, to reduce the memory capacity of the terminal device 151 storing the configuration information, the reference configuration can be not saved at the time it acquires the reference configuration and incremental configuration; instead, the serving cell's configuration information at that time can be saved as a reference configuration based on predetermined conditions such as meeting wireless quality requirements. Furthermore, it is conceivable that when the serving cell's configuration information is saved as a reference configuration at the time it acquires the reference configuration and incremental configuration, and the terminal device 151 receives a serving cell configuration change instruction from the network after saving the reference configuration, the serving cell's configuration information and the content of the reference configuration may be inconsistent. Therefore, to prevent this inconsistency, when receiving a serving cell configuration change instruction from the network after saving the reference configuration, an instruction can be sent from the network to the terminal device 151 to make changes to the same content for both the serving cell and the reference configuration. In this case, it is also possible to indicate the change of the serving cell setting from the network without indicating the repeated changes, so that the terminal device 151 will spontaneously change the reference configuration to the same content as the serving cell setting even without explicit instruction.

[0069] Furthermore, for each setting item related to cell configuration information, there are two types of information: mandatory and optional. If a mandatory setting item is not notified to the terminal device 151, the configuration information is deemed inappropriate. Therefore, the message format (message form) for notifying existing cell configuration information that does not use the reference configuration must include the mandatory setting items. However, when generating configuration information using both the reference configuration and incremental configuration, it is permissible to omit the mandatory setting items from the candidate cell configuration and instead include them in the incremental configuration during notification. In this case, the mandatory setting items can be omitted from the reference configuration.

[0070] Figure 8This diagram illustrates an example of the hardware configuration of the MN100, SN, and terminal device 151 described above. In one example, the MN100, SN, and terminal device 151 are configured with a processor 801, a ROM 802, a RAM 803, a storage device 804, and a communication circuit 805. The processor 801 is a computer configured with one or more processing circuits, such as a general-purpose CPU (Central Processing Unit) or an ASIC (Application-Specific Integrated Circuit). It executes the overall processing of the MN100, SN, and terminal device 151, as well as the individual processes described later, by reading and executing programs stored in the ROM 802 and the storage device 804. The ROM 802 is a read-only memory that stores programs, various parameters, and other information related to the processing executed by the MN100, SN, and terminal device 151. The RAM 803 functions as a workspace for the processor 801 when executing programs and also stores temporary information in a random access memory. The storage device 804 is, for example, a removable external storage device. The communication circuit 805 is a communication circuit that includes a wired interface or a wireless interface for enabling communication between MN100, SN, and terminal device 151.

[0071] Figure 9 This is a diagram outlining an example of the functional configuration of terminal device 151. Furthermore, Figure 9 Each functional unit shown can be implemented, for example, by the processor 801 executing a program stored in ROM 802, or by providing dedicated hardware to implement each function. Furthermore, Figure 9 The functions related to the processing involved in this embodiment are specifically shown. The terminal device 151 can, of course, have functions typical of a terminal device, such as performing communication according to the 3GPP (registered trademark) cellular communication standard. Furthermore, Figure 9 Two or more functional modules shown can be integrated into one functional module, or a functional module can be divided into multiple functional modules. The terminal device 151, as its function, includes, for example, a reference configuration acquisition unit 901, an incremental configuration acquisition unit 902, a setting information generation unit 903, a suitability determination unit 904, and an information notification unit 905. Furthermore, while this description pertains to the function of a secondary cell, the terminal device 151 may also have the same function regarding candidate cells as the handover destination of the primary cell.

[0072] The reference configuration acquisition unit 901 acquires, for example, a reference configuration that can be used in the configuration information of candidate cells for adding / changing secondary cells from MN100. The reference configuration acquisition unit 901 acquires the reference configuration and information associated with that reference configuration ID. The incremental configuration acquisition unit 902 acquires the incremental configuration used in generating configuration information related to each of the aforementioned candidate cells. The incremental configuration is cell-specific information and is acquired in the form of an association with a reference configuration ID to indicate which reference configuration it should be combined with. Furthermore, the reference configuration and incremental configuration can be acquired together from MN100 (within one message), but this is not a limitation. That is, the reference configuration can be acquired in a first message, and the incremental configuration in a second message different from the first message. Additionally, when updating configuration information, only either the reference configuration or the incremental configuration can be notified to the terminal device 151. The configuration information generation unit 903 combines the acquired incremental configuration and the reference configuration with a reference configuration ID associated with its incremental configuration to generate configuration information for candidate cells associated with its incremental configuration. Furthermore, the setting information generation unit 903 can generate setting information at the time when the reference configuration and incremental configuration are acquired. For example, it can generate setting information for cells whose wireless quality measured in the terminal device 151 meets predetermined conditions, and not generate setting information for cells that do not meet predetermined conditions. The suitability determination unit 904 evaluates whether the setting information generated by the setting information generation unit 903 can be used by the terminal device 151, whether there are any missing necessary parameters, and whether the terminal device 151 can interpret it, and determines whether the setting information is appropriate. If the setting information is inappropriate, the information notification unit 905 sends a predetermined notification to the MN100 and SN in the connection. Afterwards, if at least one of the reference configuration and incremental configuration is updated, information can be obtained through the reference configuration acquisition unit 901 or the incremental configuration acquisition unit 902 to update the setting information.

[0073] Figure 10 This is a diagram outlining an example of the functional configuration of the MN100. Furthermore, Figure 10 Each functional unit shown can be implemented, for example, by the processor 801 executing a program stored in ROM 802, or by providing dedicated hardware to implement each function. Furthermore, Figure 10 The functions related to the processing involved in this embodiment are specifically shown. Of course, the MN100 can also have functions as a typical base station device, such as performing communication according to the 3GPP (registered trademark) cellular communication standard. Furthermore, Figure 10Two or more functional modules shown can be integrated into one functional module, or a functional module can be divided into multiple functional modules. MN100, for example, includes a setting generation instruction unit 1001, a reference configuration acquisition unit 1002, an incremental configuration acquisition unit 1003, an update processing unit 1004, and an information notification unit 1005. Furthermore, while this description focuses on the secondary cell, MN100 can also have the same functions for candidate cells that are the handover destinations of the primary cell.

[0074] The configuration generation instruction unit 1001 instructs the SN of a candidate cell with a sub-cell to generate configuration information for connection to its cell. Here, the configuration generation instruction unit 1001, for example, instructs the SN to generate configuration information in the form of a combination of reference configuration and incremental configuration. The configuration generation instruction unit 1001 may, for example, instruct the SN to generate a full configuration if the number of reference configurations is at its maximum, so that no new reference configurations are subsequently configured. The reference configuration acquisition unit 1002 may, for example, generate the reference configuration within the device itself. Alternatively, the reference configuration acquisition unit 1002 may, for example, receive the reference configuration generated in its SN from its SN. The incremental configuration acquisition unit 1003 acquires the incremental configuration inherent to each of the SN's sub-cells from the SN. The incremental configuration is associated with a reference configuration ID indicating which reference configuration combination should be used. The update processing unit 1004, for example, sends an instruction to the SN to generate a new reference configuration and incremental configuration if at least one of the reference configuration and incremental configuration needs to be updated. After the instruction is sent via the update processing unit 1004, at least one of the updated reference configuration and incremental configuration is obtained via the reference configuration acquisition unit 1002 and the incremental configuration acquisition unit 1003. The information notification unit 1005 provides the obtained reference configuration and incremental configuration to the terminal device 151. The information notification unit 1005 may notify the terminal device 151 of information containing a reference configuration ID indicating which reference configuration the incremental configuration should be combined with.

[0075] Figure 11 This is a diagram outlining the functional configuration examples of SN101 and SN102. Furthermore, Figure 11 Each functional unit shown can be implemented, for example, by the processor 801 executing a program stored in ROM 802, or by providing dedicated hardware to implement each function. Furthermore, Figure 11 The functions related to the processing involved in this embodiment are specifically shown. SN101 and SN102 can, of course, have functions as typical terminal devices, such as performing communication according to 3GPP (registered trademark) cellular communication standards. Furthermore, Figure 11Two or more functional modules shown can be integrated into one functional module, or a functional module can be divided into multiple functional modules. SN101 and SN102, for example, include an indication receiving unit 1101, a reference configuration acquisition unit 1102, an incremental configuration acquisition unit 1103, and an information notification unit 1104. Furthermore, regarding the sub-cell, a base station device that replaces SN as a candidate for MN can also have the same function as a candidate cell for the handover destination of the primary cell.

[0076] Instruction receiving unit 1101 receives instructions from MN. For example, instruction receiving unit 1101 can receive a message from MN indicating that an incremental configuration should be generated. Additionally, instruction receiving unit 1101 can also receive instructions from MN indicating that a reference configuration should be generated. For example, if instruction receiving unit 1101 receives an instruction containing a reference configuration generated by MN, it can determine that the instruction is an instruction to generate an incremental configuration. Furthermore, if instruction receiving unit 1101 receives an instruction that does not contain a reference configuration, it can determine that the instruction is an instruction to generate both a reference configuration and an incremental configuration. Additionally, instruction receiving unit 1101 can receive an update instruction for at least one of the reference configuration and the incremental configuration from MN. Reference configuration acquisition unit 1102 can, for example, acquire a reference configuration included in an instruction received by instruction receiving unit 1101. Furthermore, if, for example, an instruction received by instruction receiving unit 1101 does not contain a reference configuration, and the use of the reference configuration included in the instruction is rejected, reference configuration acquisition unit 1102 generates and acquires a new reference configuration. The incremental configuration acquisition unit 1103 acquires the configuration information for communication in subordinate cells and the difference between the reference configuration acquired by the reference configuration acquisition unit 1102 and the incremental configuration. Furthermore, the incremental configuration acquisition unit 1103 can, for example, cause subordinate DUs to generate incremental configurations and acquire the generated incremental configurations from the DUs. The information notification unit 1104 notifies the MN of the acquired incremental configuration information. Furthermore, if the reference configuration is generated in the SN, the information notification unit 1104 notifies the MN of its reference configuration. Additionally, the information notification unit 1104 notifies the MN of the reference configuration ID indicating which reference configuration combination the incremental configuration should be associated with.

[0077] Furthermore, at least some of the functions described above as MN can also be performed by the SN connected to the terminal device 151.

[0078] Thus, according to this embodiment, reference configuration and incremental configuration can be used to appropriately set or manage configuration information for communication in a new cell that the terminal device should connect to. Therefore, the setting process of reference configuration and incremental configuration related to the handover of conditions in the terminal device, the addition or change of sub-cells with conditions, can be performed efficiently. Therefore, it can contribute to Goal 9 of the UN-led Sustainable Development Goals (SDGs): “Building resilient infrastructure, promoting sustainable industrialization and expanding innovation.”

[0079] The invention is not limited to the above-described embodiments, and various modifications and alterations can be made within the scope of the invention's intent.

[0080] This application claims priority based on Japanese Patent Application No. 2023-079348, filed on May 12, 2023, the entire contents of which are incorporated herein by reference.

Claims

1. A base station device, wherein, The base station device has: An acquisition agency acquires information relating to multiple cells for generating conditional handover (CHO) or conditional addition or modification (CPAC) of secondary cells in a connected terminal device, and the information includes: a reference configuration shared by two or more of the multiple cells, and the reference configuration is assigned identification information that uniquely identifies the reference configuration; incremental configurations inherent to each of the two or more cells; and the identification information of a reference configuration to which the incremental configurations should be combined. A providing organization that provides the terminal device with the information and the conditions for executing the CHO or the CPAC; as well as An instruction mechanism that, when it is necessary to delete or change at least one of the reference configuration and the incremental configuration, instructs the terminal device to delete or change at least one of the reference configuration and the incremental configuration.

2. The base station apparatus according to claim 1, wherein, The indicating mechanism uses the identification information to specify the reference configuration.

3. The base station apparatus according to claim 1, wherein, The instruction mechanism uses a cell identifier of the cell employing the incremental configuration, or information determining information elements, in order to specify the incremental configuration. These information elements are formed by combining the conditions used for the CHO or the CPAC, the incremental configuration, and the identification information indicating whether it should be combined with the incremental configuration.

4. The base station apparatus according to claim 1, wherein, In the absence of an incremental configuration that should be combined with the reference configuration, the indicating mechanism indicates the deletion of the reference configuration.

5. The base station apparatus according to claim 1, wherein, When an instruction is given to change the reference configuration or the incremental configuration, the instruction mechanism notifies the terminal device of differential information indicating the setting items that should be changed in the reference configuration or the incremental configuration.

6. The base station apparatus according to claim 1, wherein, When an instruction is given regarding a change to the reference configuration or the incremental configuration, the instruction mechanism notifies the terminal device of the reference configuration or the incremental configuration that should be replaced.

7. A terminal device, wherein, The terminal device has: An acquisition mechanism obtains information and conditions from a connected base station device. The information is information for generating configuration information related to multiple cells for conditional handover (CHO) or conditional addition or modification (CPAC) of secondary cells, and includes a reference configuration shared by two or more of the multiple cells and an incremental configuration inherent to each of the two or more cells. The conditions are conditions for executing the CHO or the CPAC. A generating mechanism that, for at least any one of the two or more cells, uses the incremental configuration and the reference configuration to generate configuration information for communication in that cell; An execution mechanism, upon receiving an instruction specifying the deletion or modification of at least one of the reference configuration and the incremental configuration, executes the deletion or modification of at least one of the specified reference configuration and the incremental configuration; as well as An actuator that, based on the conditions being met, uses the generated setting information to execute the CHO or the CPAC.

8. The terminal device according to claim 7, wherein, The reference configuration is assigned unique identification information that identifies the reference configuration, and the information also includes the identification information of the reference configuration that should be combined with the incremental configuration.

9. The terminal device according to claim 7, wherein, The deletion or modification instruction includes the identification information as information specifying the reference configuration.

10. The terminal device according to claim 7, wherein, The deletion or modification instruction includes, as information specifying the incremental configuration, a cell identifier of the cell using the incremental configuration, or information determining information elements, which are formed by combining the conditions for the CHO or the CPAC, the incremental configuration, and the identification information indicating whether it should be combined with the reference configuration.

11. The terminal device according to claim 7, wherein, If the deletion of the reference configuration is indicated, the reference configuration is deleted, and the incremental configuration that should be combined with the reference configuration is also deleted.

12. The terminal device according to claim 7, wherein, The indication of a change to the reference configuration or the incremental configuration includes differential information indicating the setting items that should be changed in the reference configuration or the incremental configuration.

13. The terminal device according to claim 7, wherein, The indication of a change to the reference configuration or the incremental configuration includes the reference configuration or the incremental configuration that should be replaced.

14. The terminal device according to claim 7, wherein, When the terminal device transitions from a connected state to an idle state, the actuator automatically deletes the reference configuration and the incremental configuration.

15. The terminal device according to claim 7, wherein, In the absence of instructions from the base station device in the connection and with the use of the secondary cell stopped, delete the reference configuration and the incremental configuration.

16. A control method, wherein the control method is executed by a terminal device, wherein, The control method includes: Information is obtained relating to multiple cells for generating conditional handover (CHO) or conditional secondary cell addition or modification (CPAC) in connection with terminal devices, and the information includes: a reference configuration shared by two or more of the multiple cells, and the reference configuration is assigned identification information that uniquely identifies the reference configuration; incremental configurations inherent to each of the two or more cells; and the identification information of the reference configuration to which the incremental configurations should be combined. Provide the terminal device with the information and the conditions for executing the CHO or the CPAC; and When it is necessary to delete or change at least one of the reference configuration and the incremental configuration, the terminal device is instructed to delete or change the reference configuration and the incremental configuration.

17. A control method, wherein the control method is executed by a terminal device, wherein, The control method includes: Information and conditions are obtained from the base station device in the connection. The information is information for generating multiple cells related to conditional handover (CHO) or conditional addition or modification (CPAC) of secondary cells, and includes a reference configuration shared by two or more of the multiple cells and an incremental configuration inherent to each of the two or more cells. The conditions are conditions for executing the CHO or the CPAC. For at least any one of the two or more cells, the incremental configuration and the reference configuration are used to generate configuration information for communication in that cell; Upon receiving an instruction specifying the deletion or modification of at least one of the reference configuration and the incremental configuration, perform the deletion or modification of at least one of the specified reference configuration and the incremental configuration; and Depending on whether the conditions are met, the generated setting information is used to execute the CHO or the CPAC.

18. A program in which, The program is used to enable the computer to function as a base station device as described in any one of claims 1 to 6.

19. A program in which, The program is used to enable the computer to function as a terminal device as described in any one of claims 7 to 15.

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