Terminal device, base station device, control method, and program for reducing network power consumption

Abstract

This terminal device performs communication by using carrier aggregation (CA) in a first wireless communication system conforming to the first-generation cellular communication standard. The terminal device: receives, from a base station device of the first wireless communication system, configuration information that pertains to CA in which a first cell provided by the base station device is defined as a primary cell and a second cell of the first wireless communication system provided from a position different from the primary cell is defined as a secondary cell, and that includes information for the terminal device to receive a synchronization signal of a third cell of a second wireless communication system conforming to the second generation cellular communication standard different from that of a first generation, the synchronization signal being used at least for establishing time synchronization in the secondary cell and being treated as provided from the same position as the second cell; executes at least the establishment of the time synchronization in the secondary cell on the basis of the synchronization signal of the second wireless communication system; and performs communication with the primary cell and the secondary cell by using CA.

Description

Terminal equipment, base station equipment, control method, and program for reducing network power consumption 【0001】 This invention relates to a power saving technology for networks in communications using carrier aggregation (CA). 【0002】 Currently, wireless communication systems conforming to the fifth-generation (5G) cellular communication standard are widely deployed, and various studies are underway for the standardization of the next-generation sixth-generation (6G) system. It is assumed that 5G systems will be in operation when 6G systems are introduced. Therefore, it is assumed that 5G and 6G systems will use the same frequency band as was done between the fourth-generation (4G) and 5G systems (see Non-Patent Literature 1). In addition, 5G uses carrier aggregation (CA) to improve peak throughput by using multiple frequency bands simultaneously, and it is assumed that CA will also be used in 6G. Each of these multiple frequency bands is called a component carrier (CC) or cell. 【0003】In recent years, not only power saving of terminal devices but also power saving of networks has been demanded. For this reason, in 5G, a technology called SSB-less Scell has been introduced. Usually, in a plurality of CCs used in CA, synchronization signals (SS) / physical broadcast channels (PBCH) blocks (SSB) are transmitted in order to provide time synchronization and system information respectively. On the other hand, in SSB-less Scell, when the communications of a plurality of CCs used in CA are treated as being provided from the same position, the transmission of SS in a specific secondary cell (Scell) is omitted. When the transmission of SS is omitted, the terminal device cannot perform time synchronization and automatic gain control (AGC) that operate based on SS. On the other hand, in SSB-less Scell, the reference for time synchronization and AGC for that Scell is entrusted to the SS of other CCs. That is, the terminal device acquires timing synchronization and performs AGC for the Scell where the transmission of SS is stopped by referring to the SSB in other CCs. By stopping the transmission of SS in a specific Scell, signals that must be transmitted periodically are reduced, so that the power consumption of the network can be suppressed. 【0004】 3GPP (registered trademark) contribution, RP-182635, "Spectrum sharing and corresponding UE capabilities" 【0005】In 6G, it is expected that the SSB-less Scell ​​mechanism will be extended and applied to CCs (which are sometimes called non-collocated CCs) that are provided from different locations. Between such non-collocated CCs, terminal equipment cannot perform time synchronization or AGC for one CC based on the SSB of the other CC. In other words, if the locations where the two CCs are provided (for example, the locations of base station equipment or transceiver points (TRPs)) are significantly different, if terminal equipment performs time synchronization or AGC for the other CC based on the SSB of one CC, it will not be able to properly communicate with the other CC. For this reason, conventionally, SSB-less Scell ​​has only been usable in limited environments and has not been able to sufficiently suppress network power consumption. 【0006】 This invention provides a technology that expands the environment in which network power saving can be applied in carrier aggregation (CA). 【0007】 A terminal device according to one aspect of the present invention is a terminal device that communicates using carrier aggregation (CA) in a first wireless communication system compliant with a first-generation cellular communication standard, and includes receiving means for receiving setting information relating to CA from a base station device of the first wireless communication system, wherein a first cell provided by the base station device is designated as the primary cell and a second cell of the first wireless communication system provided from a different location from the primary cell is designated as the secondary cell, and the setting information includes information for the terminal device to receive a synchronization signal of a third cell of a second wireless communication system compliant with a second-generation cellular communication standard different from the first generation, which is treated as being provided from the same location as the second cell and is used at least to establish time synchronization in the secondary cell; executing means for at least establishing time synchronization in the secondary cell based on the synchronization signal of the second wireless communication system; and communication means for communicating using CA with the primary cell and the secondary cell. 【0008】A base station device according to one aspect of the present invention is a base station device for a first wireless communication system conforming to a first-generation cellular communication standard, wherein the first wireless communication system has a notification means for notifying a terminal device that communicates using carrier aggregation (CA) in which a first cell provided by the base station device is a primary cell and a second cell of the first wireless communication system provided from a different location from the primary cell is a secondary cell, of setting information including information for the terminal device to receive a synchronization signal of a third cell of a second wireless communication system conforming to a second-generation cellular communication standard different from the first generation, which is treated as being provided from the same location as the second cell and is used for time synchronization in the secondary cell. 【0009】 According to the present invention, the environment in which network power saving can be applied in carrier aggregation (CA) can be expanded, and the power consumption reduction effect can be improved. 【0010】 Other features and advantages of the present invention will become apparent from the following description with reference to the accompanying drawings. In the accompanying drawings, the same or similar components are given the same reference numeral. 【0011】 The attached drawings are included in the specification and constitute a part thereof, illustrating embodiments of the present invention and are used to explain the principles of the present invention together with the description thereof. A diagram showing an example of the configuration of a wireless communication system. A diagram illustrating the schematic operation of the SSB-less Scell ​​according to this embodiment. A diagram illustrating the schematic operation of the SSB-less Scell ​​according to this embodiment. A diagram showing an example of the configuration of a conventional FrequencyInfoDL. A diagram showing an example of the configuration of FrequencyInfoDL according to this embodiment. A diagram showing an example of the configuration of FrequencyInfoDL according to this embodiment. A diagram showing an example of the configuration of FrequencyInfoDL according to this embodiment. A diagram showing an example of the hardware configuration of a base station device and a terminal device. A diagram showing an example of the functional configuration of a base station device. A diagram showing an example of the functional configuration of a terminal device. A diagram showing an example of the processing flow executed in a wireless communication system. 【0012】The embodiments will be described in detail below with reference to the attached drawings. Note that the following embodiments do not limit the invention as defined in the claims, and not all combinations of features described in the embodiments are essential to the invention. Two or more of the features described in the embodiments may be combined in any way. Furthermore, identical or similar configurations will be given the same reference numeral, and redundant descriptions will be omitted. 【0013】(System Configuration) Figure 1 shows an example of the configuration of the wireless communication system according to this embodiment. This wireless communication system is a cellular communication system that performs communication compliant with, for example, fifth-generation (5G) and sixth-generation (6G) cellular communication standards. This wireless communication system is configured to include, for example, a 6G base station device 102 and a 5G base station device 111. The 6G base station device 102 and the 5G base station device 111 are base station devices that are located in the same location or can be treated as being located in the same location. The 6G base station device 102 provides a 6G cell 122, and the 5G base station device 111 provides a 5G cell 131. The 6G base station device 102 and the 5G base station device 111 share a common frequency band (FR1) in at least a portion of the area. Here, sharing of the frequency band means that both the 6G base station device 102 and the 5G base station device 111 can provide communication services in a certain frequency band included within the range of FR1. In other words, the frequency bands used by the cell 122 provided by the 6G base station device 102 and the cell 131 provided by the 5G base station device 111 may partially or completely overlap, or they may not overlap at all. For example, the 6G base station device 102 and the 5G base station device 111 may be configured to provide different component carriers (CCs) within the range of FR1. In this embodiment, CC may be read as cell. In any case, the 6G base station device 102 and the 5G base station device 111 are to operate synchronously. The wireless communication system also comprises a 6G base station device 101. The 6G base station device 101 is a base station device located at a different location from the 6G base station device 102 and the 5G base station device 111, and forms cell 121 using a different frequency band (FR3) than FR1. This is just one example, and the 6G base station equipment 101 may be configured to provide CC in a different frequency band than the 6G base station equipment 102 and the 5G base station equipment 111 within the range of FR1. 【0014】Terminal device 103 is configured to perform at least 6G communication. Terminal device 103 is located in the overlapping area of ​​cell 121 and cell 122 (an area where it can communicate with both base station device 101 and base station device 102), and performs communication by carrier aggregation (CA) using cell 121 (first CC) and cell 122 (second CC), for example. Here, cell 121 (first CC) provided by base station device 101 is assumed to be the primary cell (Pcell), and cell 122 (second CC) provided by base station device 102 is assumed to be the secondary cell (Scell). 【0015】 In this embodiment, SSB-less SSB technology is applied to suppress network power consumption by stopping the transmission of synchronization signals (SS) in Cell. Note that SSB-less Cell may be configured to stop the transmission of not only SS but also the entire SS / Physical Broadcast Channel (PBCH) block (SSB). That is, the transmission of SS (or SSB) in cell 122 is stopped, and the terminal device 103 uses the SSB in other cells as a reference for time synchronization and AGC of cell 122. Here, the terminal device 103 has cell 121 as Pcell and cell 122 as Cell, and the SS of cell 122 is stopped. In this case, the terminal device 103 cannot establish time synchronization with cell 122 or perform AGC via the SSB transmitted in cell 121. In other words, because the base station device 101 providing cell 121 and the base station device 102 providing cell 122 are located in different locations (non-collated), the terminal device 103 cannot reuse the time synchronization established with base station device 101 or the gain control results by AGC for time synchronization with base station device 102. 【0016】In this embodiment, in view of these circumstances, the terminal device 103 is configured to establish time synchronization and perform AGC for cell 122 based on the 5G SSB provided by the 5G base station device 111. That is, the 6G base station device 102 stops transmitting 6G SS based on the SSB transmitted from the 5G base station device 111, which is located at (almost) the same location, rather than the 6G base station device 101, which is located at a significantly different location. The system information (PBCH) for cell 122 may be transmitted in cell 121 or in the 5G cell 131. This makes it possible for the terminal device 103 to stop transmitting the SSB of the 6G CC provided from a different location than other CCs when using 6G CC and performing CA without using 5G CC. By enabling the cessation of SSB transmission in non-collocated CCs, it becomes possible to flexibly reduce power consumption across the entire network. 【0017】 Figures 2A and 2B schematically illustrate the operation of the SSB-less Scell ​​according to this embodiment. Figure 2A shows an example where cell 122 of 6G and cell 131 of 5G share the same frequency band, and Figure 2B shows an example where cell 122 and cell 131 use different frequency bands. In either case, since cell 121 and cell 122 of 6G are in a non-collated relationship, when SS transmission is omitted in cell 122, cell 121 (FR3, Pcell) is not referenced. On the other hand, since cell 122 of 6G is in a collated relationship with cell 131 of 5G, when transmission in cell 122 is omitted, the SS of cell 131 is referenced. 【0018】On the other hand, conventionally, when stopping the transmission of SS from a specific Cell, the configuration for referencing the SSB of another cell requires that the other cell be a serving cell. Figure 3 shows an example of an information element called FrequencyInfoDL included in a conventional RRC (Radio Resource Control) message (e.g., an RRC Reconfiguration message). FrequencyInfoDL is part of the configuration information for a Cell, and the other cell to be referenced when SS transmission is stopped for this Cell is specified by the information "referenceCell". Here, referenceCell specifies the other cell to be referenced by the configured serving cell identification information (ServCellIndex). In other words, a cell that is not a serving cell cannot be used as a reference cell, and the terminal device 103 cannot reference the SS of the 5G cell 131 for purposes such as time synchronization of the 6G cell 122. 【0019】In contrast, in this embodiment, as shown in Figure 4 for example, new information "referenceFrequencySSB" can be defined to indicate the frequency position of the SS to be referenced. In this referenceFrequencySSB, for example, the Absolute Radio Frequency Channel Number (ARFCN), which is the frequency position of 5G, is specified. In the example in Figure 4, a configuration is shown in which the variable ARFCN-ValueNR, which can be specified as the frequency position of 5G, can be set in referenceFrequencySSB. Note that the frequency position specified here may or may not match the frequency position used when the SSB of cell 122 of 6G is transmitted. As a result, the 6G base station device 101 can, for example, specify the frequency position to which the SS of cell 131 is transmitted as a reference for cell 122 using an RRC message. Then, based on that information, the terminal device 103 establishes time synchronization of the Cell (cell 122) and operates AGC based on the 5G SS (SS transmitted in cell 131) transmitted at the specified frequency position. In this way, in an environment where 5G and 6G coexist, if 5G and 6G cells are treated as being provided from the same location, the terminal device 103 can stop the SS of the 6G cell 122 by observing the SS of the 5G cell 131. Note that in the example of Figure 4, since a frequency position is specified, the SS transmitted at that frequency position does not necessarily have to be a 5G SS. That is, the frequency position of a 4G SS may be specified, and the terminal device 103 may establish time synchronization of the 6G cell 122 based on the 4G SS. 【0020】Furthermore, CA can be configured in FR1 using 6G cell 122 and 5G cell 131. In this case, terminal device 103 may acquire information about cell 131 as Cell configuration information when cell 131 is used in CA. Note that cell 131 does not have to be used in actual CA communication. That is, while configuration information for Cell is prepared, this configuration information is used only as information for receiving the SSB of cell 131, and actual communication based on this configuration does not have to be performed. In other words, configuration information defining cell 131 as a serving cell is notified to terminal device 103, and terminal device 103 may be able to identify the location of the referenced SS using the information specifying the serving cell. For this purpose, for example, as shown in Figure 5, information "referenceInter-RAT" is defined, and in this information, identification information (ServCellIndex) of a cell configured as a serving cell of another RAT (Radio Access Technology) can be specified. This allows the terminal device 103 to refer to the service station (SS) of the 5G cell 131 for purposes such as time synchronization of the 6G cell 122. Furthermore, when specifying an SS for a different RAT, an SS other than 5G, such as 4G, may be specified. This allows the terminal device 103 to establish time synchronization of the 6G cell 122 based on the 4G SS. 【0021】 Furthermore, if the terminal device 103 can only interpret narrowband signals, information on the Bandwidth part (BWP) from the available frequency band in cell 131 to which the referenced SS is transmitted may be notified to the terminal device 103. In this case, for example, as shown in Figure 6, a ServingCellAndBWP-Id corresponding to the combination of the identification information of cell 131 (ServCellIndex) and the information specifying the BWP (BWP-Id) is specified in referenceInter-RAT. The terminal device 103 can then identify the combination of the cell to which the referenced SS is transmitted and the BWP using this information. 【0022】(Device Configuration) Next, the device configuration will be described. Figure 7 shows an example of the hardware configuration of the base station device 101 and terminal device 103 that provide the Pcell (cell 121) of this embodiment. Note that the base station device 102 and base station device 111 are communication devices that have the capability to stop SS transmission using conventional SSB-less Scell, and their description is omitted here. In one example, the base station device 101 and terminal device 103 are configured to include a processor 701, ROM 702, RAM 703, storage device 704, and communication circuit 705. The processor 701 is a computer configured to include one or more processing circuits, such as a general-purpose CPU (central processing unit) or ASIC (application-specific integrated circuit), and executes the overall processing of the device and the above-mentioned processing by reading and executing programs stored in the ROM 702 and storage device 704. ROM 702 is a read-only memory that stores information such as programs and various parameters related to the processing performed by the base station device 101 and the terminal device 103. RAM 703 functions as a workspace for the processor 701 when executing programs and is a random access memory that stores temporary information. Storage device 704 is composed of, for example, a removable external storage device. Communication circuit 705 is composed of, for example, a circuit for wireless communication of 5G or its successor standards. Although one communication circuit 705 is shown in Figure 7, the base station device 101 and the terminal device 103 may have multiple communication circuits. For example, the base station device 101 and the terminal device 103 may have wireless communication circuits for 5G, 6G, and, if necessary, for 4G and successor standards of 6G, and an antenna common to these circuits. The base station device 101 and the terminal device 103 may also have separate antennas suitable for each standard. Furthermore, the base station device 101 may also have a wired communication circuit used for communicating with other base station devices or nodes of the core network. In addition, the terminal device may also have a communication circuit compliant with wireless communication standards other than cellular communication standards, such as a wireless local area network (LAN) or Bluetooth®.The base station device 101 and the terminal device 103 may have separate communication circuits 705 for each of the multiple usable frequency bands, or they may have a common communication circuit 705 for at least a portion of those frequency bands. 【0023】 Figure 8 shows an example of the functional configuration of a base station device 101 that provides Pcell to a terminal device 103 that performs CA. The base station device 101 is configured to include, for example, a setting information generation unit 801 and a setting information notification unit 802. Note that Figure 8 mainly shows the functions of the base station device 101. The base station device 102 that provides Scell ​​is assumed to be a general 6G base station device configured to stop SS transmission in the same way as 5G SSB-less Scell, and its explanation is omitted here. Similarly, the 5G base station device 111 is a general 5G base station device, so its explanation is also omitted here. Note that Figure 8 shows only the functions particularly relevant to this embodiment, and various other functions that the base station device 101 may have are not shown. For example, the base station device 101 naturally has other functions that a base station device compliant with the 6G cellular communication standard generally has. Also, the functional blocks in Figure 8 are shown schematically, and each functional block may be implemented as an integrated unit, or it may be further subdivided. Furthermore, each function in Figure 8 may be realized, for example, by the processor 701 executing a program stored in the ROM 702 or the storage device 704, or by a processor located inside the communication circuit 705 executing predetermined software. The details of the processing performed by each functional unit will not be repeatedly explained here, but only their general functions will be outlined. 【0024】The configuration information generation unit 801 generates configuration information that allows for the identification of other cells to be referenced for establishing time synchronization, etc., for the SSB-less Cell (cell 122) provided by the base station device 102. In other words, the configuration information generation unit 801 generates configuration information that allows the terminal device 103 to receive the SS of another RAT (e.g., 5G) cell, which is treated as being provided from the same location as the 6G SSB-less Cell (i.e., it is in a collated relationship). Specifically, configuration information like that described using Figures 4 to 6 above is generated. The configuration information notification unit 802 notifies the terminal device 103 of the configuration information generated by the configuration information generation unit 801. The configuration information notification unit 802 generates, for example, an RRC message containing the generated configuration information and transmits it to the terminal device 103. 【0025】 Figure 9 shows an example of the functional configuration of the terminal device 103. The terminal device 103 is composed of, for example, a setting information receiving unit 901, an SS receiving unit 902, and a communication control unit 903. Note that Figure 9 shows only the functions particularly relevant to this embodiment, and various other functions that the terminal device 103 may have are not shown. For example, the terminal device 103 naturally has other functions that terminal devices conforming to the 6G cellular communication standard generally have. Also, the functional blocks in Figure 9 are shown schematically, and each functional block may be implemented as an integrated unit or further subdivided. Furthermore, each function in Figure 9 may be implemented, for example, by the processor 701 executing a program stored in the ROM 702 or storage device 704, or by a processor located inside the communication circuit 705 executing predetermined software. Note that the details of the processing performed by each functional unit will not be repeatedly explained here, and only the general functions will be outlined. 【0026】The configuration information receiving unit 901 receives configuration information from the base station device 101. For example, the configuration information receiving unit 901 receives an RRC message transmitted from the base station device 101 and obtains configuration information about cell 122 contained in the message. Based on this configuration information, the terminal device 103 recognizes that cell 122 is an SSB-less Cell and obtains information about the cell to be referenced for establishing time synchronization of the SSB-less Cell. In this embodiment, configuration information is obtained for the terminal device 103 to reference another RAT (5G) cell 131 which is treated as being provided from the same location as the SSB-less Cell (cell 122) for time synchronization of the SSB-less Cell (cell 122) when the terminal device 103 performs CA communication with 6G cells 121 and 122. The SS receiving unit 902 receives the SS of the referenced 5G cell 131 based on the configuration information obtained by the configuration information receiving unit 901. The communication control unit 903 performs CA-based communication between cell 121, which is a Pcell, and cell 122, which is a Scell. At this time, the communication control unit 903 receives the SS of cell 131 based on the setting information received by the SS receiving unit 902, and performs processes such as establishing time synchronization and AGC for cell 122 based on that SS. 【0027】 (Processing Flow) Figure 10 shows an example of the processing flow performed in the communication system according to this embodiment. As mentioned above, the 6G base station equipment 101 and base station equipment 102 are in a non-collated relationship, while the 6G base station equipment 102 and the 5G base station equipment 111 are in a collated relationship. Here, only the content of the processing will be outlined, and the details of each processing step will be omitted as they are described above. 【0028】First, the base station device 101 transmits configuration information for CA to the terminal device 103 via an RRC Reconfiguration message (S1001), and the terminal device 103 acquires the configuration information (S1002). Based on this configuration information, the terminal device 103 can perform communication using CA, with cell 121 provided by the base station device 101 as a Pcell and cell 122 provided by the base station device 102 as a Scell. Furthermore, the terminal device 103 can recognize from the configuration information that cell 122 is an SSB-less Scell ​​and that it should refer to a specific frequency position or a 5G cell 131 (and BWP) for purposes such as establishing its synchronization. 【0029】 Then, the terminal device 103 observes the 5G SS at the frequency position and cell (and BWP) to be referenced for time synchronization for cell 122, as specified by the configuration information (S1003), and performs processes such as establishing time synchronization and AGC (S1004). Then, the terminal device 103 performs CA-based communication with cell 121 and cell 122 (S1005). Here, the terminal device 103 can perform communication with cell 122 using the gain determined by the time synchronization and AGC established in S1004. 【0030】 In the above example, we described an environment in which 5G and 6G wireless communication systems coexist, but this is not the only example. That is, 5G and 6G are examples of different generations of wireless communication systems, and the above discussion can be applied to environments in which a first-generation wireless communication system and a second-generation wireless communication system coexist, such as 6G and seventh generation (7G), or 4G and 6G. In this embodiment, a cellular communication system was used as an example, but the above discussion may also be applied to non-cellular communication systems with a similar configuration. 【0031】Furthermore, the various terms used in the above examples are for illustrative purposes only and may be replaced with other terms having similar meanings. For example, the information shown in Figures 4 to 6 may be referred to by other names. Also, for example, while an example was shown in which information for enabling reception of SS from the 5G base station device 111 is included in the FrequencyInfoDL information element, it may be included in other information elements as well. In other words, it is sufficient for the terminal device 103 to be notified of setting information of any name and any format necessary for enabling the terminal device 103 to receive SS from other RATs for purposes such as SSB-less Scell ​​time synchronization. 【0032】 As described above, while omitting the transmission of the SS of a non-collocated Scell, the terminal device 103 can perform processes such as establishing time synchronization for that Scell ​​based on the SS of other RATs (for example, those following legacy communication standards). This makes it possible to reduce network power consumption without reducing communication efficiency. Thus, it becomes possible to contribute to Goal 9 of the United Nations-led Sustainable Development Goals (SDGs), "Build resilient infrastructure, promote sustainable industrialization and foster innovation." 【0033】 This application claims priority based on Japanese Patent Application No. 2024-216881, filed on December 11, 2024, and all of its contents are incorporated herein by reference.

Claims

1. A terminal device that communicates using carrier aggregation (CA) in a first wireless communication system compliant with a first-generation cellular communication standard, comprising: receiving means for receiving setting information from a base station device of the first wireless communication system, the setting information relating to CA, wherein a first cell provided by the base station device is designated as the primary cell and a second cell of the first wireless communication system provided from a different location from the primary cell is designated as the secondary cell, and the setting information includes information for the terminal device to receive a synchronization signal of a third cell of a second wireless communication system compliant with a second-generation cellular communication standard different from the first generation, which is treated as being provided from the same location as the second cell and is used at least to establish time synchronization in the secondary cell; executing means for at least establishing time synchronization in the secondary cell based on the synchronization signal of the second wireless communication system; and communication means for communicating with the primary cell and the secondary cell using CA.

2. The terminal device according to claim 1, wherein the information for the terminal device to receive the synchronization signal of the third cell includes information indicating the frequency position to which the synchronization signal is transmitted.

3. The terminal device according to claim 1, wherein the setting information includes information indicating the settings when the third cell is used in CA, the setting includes identification information for specifying each cell used in CA, and the information for the terminal device to receive the synchronization signal of the third cell includes the identification information for specifying the third cell.

4. The terminal device according to claim 3, wherein the information for the terminal device to receive the synchronization signal of the third cell further includes information indicating a Bandwidth part of the frequency band used in the third cell to which the synchronization signal is transmitted.

5. The terminal device according to any one of claims 1 to 4, wherein the first wireless communication system is a sixth-generation (6G) cellular communication system, and the second wireless communication system is a fifth-generation (5G) cellular communication system.

6. A base station device for a first wireless communication system conforming to a first-generation cellular communication standard, wherein in the first wireless communication system, a first cell provided by the base station device is designated as a primary cell and a second cell of the first wireless communication system, provided from a different location than the primary cell, is designated as a secondary cell. The base station device has notification means for notifying a terminal device that communicates using carrier aggregation (CA), wherein the first cell is designated as a primary cell and a second cell of the first wireless communication system, provided from a different location than the primary cell, is designated as a secondary cell, and includes notification means for notifying the terminal device of setting information including information for receiving a synchronization signal of a third cell of a second wireless communication system conforming to a second-generation cellular communication standard different from the first generation, which is treated as being provided from the same location as the second cell and is used for time synchronization in the secondary cell.

7. The base station device according to claim 6, wherein the information for the terminal device to receive the synchronization signal of the third cell includes information indicating the frequency position to which the synchronization signal is transmitted.

8. The base station device according to claim 6, wherein the setting information includes information indicating the setting when the third cell is used in CA, the setting includes identification information for specifying each cell used in CA, and the information for the terminal device to receive the synchronization signal of the third cell includes the identification information for specifying the third cell.

9. The base station device according to claim 8, wherein the information for the terminal device to receive the synchronization signal of the third cell further includes information indicating a Bandwidth part of the frequency band used in the third cell to which the synchronization signal is transmitted.

10. The base station device according to any one of claims 6 to 9, wherein the first wireless communication system is a sixth-generation (6G) cellular communication system, and the second wireless communication system is a fifth-generation (5G) cellular communication system.

11. A control method performed by a terminal device that communicates using carrier aggregation (CA) in a first wireless communication system compliant with a first-generation cellular communication standard, comprising: receiving setting information relating to CA from a base station device of the first wireless communication system, wherein the base station device uses a first cell provided by the base station device as the primary cell and a second cell of the first wireless communication system provided from a different location from the primary cell as the secondary cell, the setting information includes information for the terminal device to receive a synchronization signal of a third cell of a second wireless communication system compliant with a second-generation cellular communication standard different from the first generation, which is treated as being provided from the same location as the second cell and is used at least to establish time synchronization in the secondary cell; at least performing the establishment of time synchronization in the secondary cell based on the synchronization signal of the second wireless communication system; and communicating with the primary cell and the secondary cell using CA.

12. A control method performed by a base station device of a first wireless communication system conforming to a first-generation cellular communication standard, the control method comprising notifying a terminal device that communicates using carrier aggregation (CA) in the first wireless communication system, where a first cell provided by the base station device is a primary cell and a second cell of the first wireless communication system provided from a different location from the primary cell is a secondary cell, of setting information including information for the terminal device to receive a synchronization signal of a third cell of a second wireless communication system conforming to a second-generation cellular communication standard different from the first generation, which is treated as being provided from the same location as the second cell and is used for time synchronization in the secondary cell.

13. A program for causing a computer installed in a terminal device to execute the control method described in claim 11.

14. A program for causing a computer installed in a base station device to execute the control method described in claim 12.

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