Base station, communication system and communication method

Abstract

To reduce a probability of a failure of setting of a band combination at the time of dual connectivity.SOLUTION: A first base station performs dual connectivity together with a second base station. The first base station comprises: a control section which determines a candidate list of band combinations to be used for the dual connectivity based on bands of primary cells in the first base station; a transmission section which transmits the candidate list to the second base station; and a reception section which receives, from the second base station, information indicating the band combination which is selected from the candidate list by the second base station. The transmission section transmits a message performing setting of cells of the second base station to a terminal, and the reception section receives a response of the message from the terminal.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to a base station in a wireless communication system, a communication system, and a communication method. [Background technology]

[0002] In the 3GPP (3rd Generation Partnership Project), a wireless communication method called 5G or NR (New Radio) (hereinafter, the wireless communication method is referred to as "NR") is being studied in order to realize a larger system capacity, a higher data transmission speed, a lower latency in wireless sections, etc. In 5G, various wireless technologies and network architectures are being studied in order to meet the requirement of achieving a throughput of 10 Gbps or more while keeping the latency in wireless sections to 1 ms or less (for example, Non-Patent Document 1).

[0003] In addition, NR supports Multi Radio Dual Connectivity (MR-DC) (for example, see Non-Patent Document 2). In MR-DC, a Master Node (MN) notifies a Secondary Node (SN) of band combinations that are permissible in dual connectivity, and the SN selects a band combination to perform communication. [Prior art documents] [Non-patent literature]

[0004] [Non-Patent Document 1] 3GPP TS 38.300 V16.4.0 (2020-12) [Non-Patent Document 2] 3GPP TS 37.340 V16.4.0 (2020-12) Summary of the Invention [Problem to be solved by the invention]

[0005] In EN-DC, which is one type of MR-DC, when an MN notifies an SN of band combinations that are acceptable for dual connectivity, the SN may not be able to select a compatible NR frequency bandwidth (CBW: Channel Band Width), resulting in an EN-DC configuration failure.

[0006] The present invention has been made in consideration of the above-mentioned points, and has an object to reduce the probability of failure in setting a band combination during dual connectivity. [Means for solving the problem]

[0007] According to the disclosed technology, a first base station that performs dual connectivity together with a second base station is provided, the first base station having a control unit that determines a candidate list of band combinations to be used for dual connectivity based on the band of a primary cell in the first base station, a transmission unit that transmits the candidate list to the second base station, and a reception unit that receives information from the second base station indicating a band combination selected by the second base station from the candidate list, the transmission unit transmitting a message to a terminal to set up a cell of the second base station, and the reception unit receiving a response to the message from the terminal. Effect of the Invention

[0008] According to the disclosed technology, a technology is provided that makes it possible to reduce the probability of failure in setting a band combination during dual connectivity. [Brief description of the drawings]

[0009] [Figure 1] 1 is a diagram illustrating a wireless communication system according to an embodiment of the present invention. [Diagram 2] 1 is a diagram illustrating a wireless communication system according to an embodiment of the present invention. [Diagram 3] 11 is an example of a specification change in an embodiment of the present invention. [Figure 4]11 is a diagram for explaining an example of setting a band combination in an embodiment of the present invention. FIG. [Diagram 5] 11 is a flowchart illustrating an example of setting a band combination according to an embodiment of the present invention. [Figure 6] FIG. 11 is a sequence diagram for explaining an example (1) of setting a band combination in an embodiment of the present invention. [Figure 7] FIG. 11 is a sequence diagram for explaining an example (2) of setting a band combination in an embodiment of the present invention. [Figure 8] 2 is a diagram illustrating an example of a functional configuration of a base station 10 according to an embodiment of the present invention. [Figure 9] 2 is a diagram illustrating an example of a functional configuration of a terminal 20 according to an embodiment of the present invention. [Figure 10] 2 is a diagram illustrating an example of a hardware configuration of a base station 10 or a terminal 20 according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Note that the embodiment described below is an example, and the embodiment to which the present invention is applied is not limited to the following embodiment.

[0011] In the operation of the wireless communication system according to the embodiment of the present invention, existing technologies are used as appropriate. However, the existing technologies are, for example, existing LTE, but are not limited to existing LTE. In addition, the term "LTE" used in this specification has a broad meaning including LTE-Advanced and systems after LTE-Advanced (e.g., NR) unless otherwise specified.

[0012] In the embodiment of the present invention described below, terms such as SS (Synchronization signal), PSS (Primary SS), SSS (Secondary SS), PBCH (Physical broadcast channel), PRACH (Physical random access channel), PDCCH (Physical Downlink Control Channel), PDSCH (Physical Downlink Shared Channel), PUCCH (Physical Uplink Control Channel), and PUSCH (Physical Uplink Shared Channel) used in existing LTE are used. This is for convenience of description, and similar signals, functions, etc. may be called by other names. In addition, the above-mentioned terms in NR correspond to NR-SS, NR-PSS, NR-SSS, NR-PBCH, NR-PRACH, etc. However, even if a signal is used in NR, it is not necessarily specified as "NR-".

[0013] Furthermore, in the embodiment of the present invention, the duplexing method may be a time division duplex (TDD) method, a frequency division duplex (FDD) method, or another method (for example, flexible duplex, etc.).

[0014] Furthermore, in the embodiment of the present invention, when radio parameters, etc. are "configured," this may mean that predetermined values ​​are pre-configured, or that radio parameters notified from base station 10 or terminal 20 are configured.

[0015] Fig. 1 is a diagram for explaining a wireless communication system in an embodiment of the present invention. As shown in Fig. 1, the wireless communication system in the embodiment of the present invention includes a base station 10 and a terminal 20. Although Fig. 1 shows one base station 10 and one terminal 20, this is an example, and there may be a plurality of each.

[0016] The base station 10 is a communication device that provides one or more cells and performs wireless communication with the terminal 20. The physical resources of a wireless signal are defined in a time domain and a frequency domain, and the time domain may be defined by the number of Orthogonal Frequency Division Multiplexing (OFDM) symbols, and the frequency domain may be defined by the number of subcarriers or the number of resource blocks. Furthermore, a Transmission Time Interval (TTI) in the time domain may be a slot or a subslot, and the TTI may be a subframe.

[0017] The base station 10 is capable of performing carrier aggregation, which aggregates multiple cells (multiple component carriers (CCs)) to communicate with the terminal 20. In carrier aggregation, one primary cell (PCell, Primary Cell) and one or more secondary cells (SCell, Secondary Cell) are used.

[0018] The base station 10 transmits a synchronization signal, system information, and the like to the terminal 20. The synchronization signal is, for example, NR-PSS and NR-SSS. The system information is, for example, transmitted by NR-PBCH or PDSCH, and is also called broadcast information. As shown in FIG. 1, the base station 10 transmits a control signal or data to the terminal 20 in DL (Downlink), and receives a control signal or data from the terminal 20 in UL (Uplink). Note that, here, what is transmitted by a control channel such as PUCCH or PDCCH is called a control signal, and what is transmitted by a shared channel such as PUSCH or PDSCH is called data, but these names are merely examples.

[0019] The terminal 20 is a communication device equipped with a wireless communication function, such as a smartphone, a mobile phone, a tablet, a wearable terminal, a communication module for M2M (Machine-to-Machine), etc. As shown in Fig. 1, the terminal 20 receives a control signal or data from the base station 10 in DL and transmits a control signal or data to the base station 10 in UL, thereby using various communication services provided by the wireless communication system. The terminal 20 may be called a UE, and the base station 10 may be called a gNB.

[0020] The terminal 20 can perform carrier aggregation, which aggregates multiple cells (multiple CCs) to communicate with the base station 10. In the carrier aggregation, one primary cell and one or more secondary cells are used. Also, a PUCCH-SCell having a PUCCH may be used.

[0021] Fig. 2 shows a configuration example of a wireless communication system in which DC (Dual connectivity) is implemented. As shown in Fig. 2, a base station 10A serving as an MN (Master Node) and a base station 10B serving as an SN (Secondary Node) are provided. The base station 10A and the base station 10B are each connected to a core network 30. The terminal 20 can communicate with both the base station 10A and the base station 10B.

[0022] A cell group provided by base station 10A, which is an MN, is called an MCG (Master Cell Group), and a cell group provided by base station 10B, which is an SN, is called an SCG (Secondary Cell Group). In addition, in a DC, an MCG is composed of one PCell and one or more SCells, and an SCG is composed of one PSCell (Primary SCG Cell) and one or more SCells.

[0023] The processing operations in this embodiment may be executed in the system configuration shown in FIG. 1, in the system configuration shown in FIG. 2, or in other system configurations.

[0024] For example, when starting EN-DC (E-UTRA NR - DC), the MN transmits an information element allowedBC-ListMRDC, which is a list of allowed band combinations, to the SN. The MN creates allowedBC-ListMRDC from the band combinations supported by the terminal 20 reported from the terminal 20.

[0025] Since the MN needs to create the allowedBC-ListMRDC by limiting it to the band combinations that it supports, depending on the method of limitation, it is expected that the SN will not be able to select the channel bandwidth (CBW) of the corresponding NR frequency, resulting in EN-DC configuration failure (EN-DC configuration failure).

[0026] Therefore, when creating allowedBC-ListMRDC, the MN may include in allowedBC-ListMRDC a band combination that includes all PCell bands supported by the MN.

[0027] Fig. 3 is an example of a specification change in an embodiment of the present invention. As shown in Fig. 3, allowedBC-ListMRDC is a list of indexes that refer to band combinations in MR-DC capabilities, and an SN is allowed to select a band combination of an SCG from the list.

[0028] The band combinations set in the list are assigned numbers based on the supportedBandCombinationList reported by the terminal 20. Furthermore, in the EN-DC, for example, numbers may be assigned based on supportedBandCombinationList-UplinkTxSwitch included in the UE-MRDC-Capability reported by the terminal 20.

[0029] Further, for each band combination set in the list, a featureSet, which is a group of parameters allowed in the band combination, is set.

[0030] In addition, all MR-DC band combinations set in the list include band combinations of MCGs that are a superset of the bands of the MCG selected by the MN.

[0031] When creating the allowedBC-ListMRDC, the MN may include in the allowedBC-ListMRDC a band combination that includes at least all bands of the PCell supported by the MN.

[0032] In addition, among the band combination list reported by the terminal 20, it is not necessary to create allowedBC-ListMRDC by limiting it to the band of the SCell supported by the MN or the band combination of the PCell and the SCell.

[0033] In addition, the MN may not create allowedBC-ListMRDC by limiting featureSetCombination from the viewpoint of featureSet in each band combination in the band combination list reported by the terminal 20. Alternatively, the MN may not create allowedBC-ListMRDC by limiting from the viewpoint of featureSet in the featureSet for each band corresponding to each band in each band combination.

[0034] Fig. 4 is a diagram for explaining an example of setting band combinations in an embodiment of the present invention. As shown in Fig. 4, allowedBC-ListMRDC is created. The MN may include all band combinations including band1 of the bands of the supported PCell, that is, BandCombination#1 to BandCombination#m shown in Fig. 4, in allowedBC-ListMRDC.

[0035] Note that the band combination including band4 shown in Fig. 4 is a band combination that is not supported by the MN. Band2 shown in Fig. 4 is the band for the SCell.

[0036] Also, as shown in Fig. 4, the MN may specify n featureSetCombinations corresponding to one BandCombination. For example, the featureSet for each band corresponding to band1 is FS(1,1) to FS(1,n). As described above, the MN does not need to create an allowedBC-ListMRDC by restricting the featureSetCombination in terms of featureSet.

[0037] 5 is a flowchart for explaining an example of setting band combinations in an embodiment of the present invention. In step S1, the MN sets all band combinations including the PCell band supported by the MN in allowedBC-ListMRDC. In the following step S2, the MN transmits allowedBC-ListMRDC to the SN. Note that, prior to step S1, the MN may have received information indicating band combinations supported by the terminal 20 from the terminal 20.

[0038] 6 is a sequence diagram for explaining an example (1) of setting a band combination in an embodiment of the present invention. In step S11, the UE 20 transmits a Measurement Report, which is a report of a measurement result, to the MN 10A. In the following step S12, the MN 10A transmits an SN Addition Request, which is an SN addition request, to the SN 10B. The SN Addition Request is an inter-node message for setting up a DC. The SN Addition Request includes allowedBC-ListMRDC in an information element CG-ConfigInfo. The allowedBC-ListMRDC in step S12 may include a band combination limited in terms of the bands of the supported PCell.

[0039] In the following step S13, the SN 10B transmits an SN Addition Request Ack to the MN 10A as a response to the SN addition request. The SN Addition Request Ack includes information indicating the band combination to be used in the SCG in the information element CG-Config. In the following step S14, the MN 10A transmits an RRC Reconfiguration for configuring the SCG to the UE 20. In the following step S15, the UE 20 transmits an RRCReconfigurationComplete indicating completion of the configuration to the MN 10A. In the following step S16, the MN 10A transmits an SN Reconfiguration Complete indicating completion of the configuration to the SN 10B.

[0040] FIG. 7 is a sequence diagram for explaining an example (2) of setting a band combination in an embodiment of the present invention. In step S21, the UE 20 transmits a Measurement Report, which is a report of a measurement result, to the MN 10A. In the following step S22, the MN 10A transmits an SN modification Request, which is an SN modification request, to the SN 10B. The SN modification Request is a message for modifying an already set up DC. The SN modification Request includes allowedBC-ListMRDC in an information element CG-ConfigInfo. The allowedBC-ListMRDC in step S22 may include band combinations limited in terms of bands of supported PCells and / or bands of supported SCells. Note that the allowedBC-ListMRDC in step S22 may include band combinations limited in terms of parameters for each supported band, i.e., featureSet. This limitation can reduce overhead of inter-node signaling.

[0041] In the following step S23, the SN 10B transmits an SN modification Request Ack to the MN 10A as a response to the SN addition request. The SN modification Request Ack includes information indicating the band combination to be used in the SCG in the information element CG-Config. In the following step S24, the MN 10A transmits an RRC Reconfiguration for configuring the SCG to the UE 20. In the following step S25, the UE 20 transmits an RRC Reconfiguration Complete indicating completion of the configuration to the MN 10A. In the following step S16, the MN 10A transmits an SN Reconfiguration Complete indicating completion of the configuration to the SN 10B.

[0042] According to the above embodiment, the MN notifies the SN of all band combinations including the band of the supported PCell, and thus the number of selectable band combinations increases when the SN selects a band combination, thereby reducing the SCG configuration failure. Furthermore, when changing the SN configuration, the MN can reduce the overhead of inter-node signaling by limiting the band combinations from the perspective of the PCell and the SCell.

[0043] In other words, the probability of failure in setting the band combination during dual connectivity can be reduced.

[0044] (Device configuration) Next, a functional configuration example of the base station 10 and the terminal 20 that execute the processes and operations described above will be described. The base station 10 and the terminal 20 include functions for executing the above-mentioned embodiments. However, the base station 10 and the terminal 20 may each include only one of the functions of the embodiments.

[0045] <Base station 10> Fig. 8 is a diagram showing an example of the functional configuration of the base station 10. As shown in Fig. 8, the base station 10 has a transmitting unit 110, a receiving unit 120, a setting unit 130, and a control unit 140. The functional configuration shown in Fig. 8 is merely an example. As long as the operation according to the embodiment of the present invention can be executed, the functional divisions and the names of the functional units may be any. The transmitting unit 110 and the receiving unit 120 may be called a communication unit.

[0046] The transmitting unit 110 has a function of generating a signal to be transmitted to the terminal 20 side and transmitting the signal wirelessly. The receiving unit 120 has a function of receiving various signals transmitted from the terminal 20 and acquiring, for example, information of a higher layer from the received signals. The transmitting unit 110 also has a function of transmitting NR-PSS, NR-SSS, NR-PBCH, DL / UL control signals, DL data, and the like to the terminal 20. The transmitting unit 110 also transmits setting information and the like described in the embodiment.

[0047] The setting unit 130 stores in a storage device setting information that is set in advance and various setting information to be transmitted to the terminal 20, and reads out the information from the storage device as necessary. The control unit 140 performs, for example, resource allocation and overall control of the base station 10. Note that the functional unit related to signal transmission in the control unit 140 may be included in the transmitting unit 110, and the functional unit related to signal reception in the control unit 140 may be included in the receiving unit 120. Furthermore, the transmitting unit 110 and the receiving unit 120 may be called a transmitter and a receiver, respectively.

[0048] <Terminal 20> Fig. 9 is a diagram showing an example of the functional configuration of the terminal 20. As shown in Fig. 9, the terminal 20 has a transmitting unit 210, a receiving unit 220, a setting unit 230, and a control unit 240. The functional configuration shown in Fig. 9 is merely an example. As long as the operation related to the embodiment of the present invention can be executed, the names of the functional divisions and the functional units may be any. The transmitting unit 210 and the receiving unit 220 may be called a communication unit.

[0049] The transmitter 210 creates a transmission signal from the transmission data and transmits the transmission signal wirelessly. The receiver 220 receives various signals wirelessly and acquires a higher layer signal from the received physical layer signal. The transmitter 210 also transmits HARQ-ACK, and the receiver 220 receives the setting information and the like described in the embodiment.

[0050] The setting unit 230 stores various setting information received from the base station 10 by the receiving unit 220 in a storage device, and reads it out from the storage device as necessary. The setting unit 230 also stores setting information that is set in advance. The control unit 240 performs control of the entire terminal 20, etc. Note that a functional unit related to signal transmission in the control unit 240 may be included in the transmitting unit 210, and a functional unit related to signal reception in the control unit 240 may be included in the receiving unit 220. Also, the transmitting unit 210 and the receiving unit 220 may be called a transmitter and a receiver, respectively.

[0051] (Hardware configuration) The block diagrams (FIGS. 8 and 9) used to explain the above embodiments show functional blocks. These functional blocks (components) are realized by any combination of at least one of hardware and software. Furthermore, the method of realizing each functional block is not particularly limited. That is, each functional block may be realized using one device that is physically or logically combined, or may be realized using two or more devices that are physically or logically separated and directly or indirectly connected (e.g., using wires, wirelessly, etc.) and these multiple devices. The functional blocks may be realized by combining the one device or the multiple devices with software.

[0052] Functions include, but are not limited to, judgment, determination, judgment, calculation, computation, processing, derivation, investigation, search, confirmation, reception, transmission, output, access, resolution, selection, selection, establishment, comparison, assumption, expectation, consideration, broadcasting, notifying, communicating, forwarding, configuring, reconfiguring, allocating, mapping, and assignment. For example, a functional block (component) that performs the function of transmission is called a transmitting unit or a transmitter. In either case, as described above, there is no particular limitation on the method of realization.

[0053] For example, the base station 10, the terminal 20, etc. in an embodiment of the present disclosure may function as a computer that performs processing of the wireless communication method of the present disclosure. Fig. 10 is a diagram showing an example of a hardware configuration of the base station 10 and the terminal 20 according to an embodiment of the present disclosure. The above-mentioned base station 10 and the terminal 20 may be physically configured as a computer device including a processor 1001, a storage device 1002, an auxiliary storage device 1003, a communication device 1004, an input device 1005, an output device 1006, a bus 1007, etc.

[0054] In the following description, the term "apparatus" can be interpreted as a circuit, a device, a unit, etc. The hardware configuration of the base station 10 and the terminal 20 may be configured to include one or more of the devices shown in the figure, or may be configured to exclude some of the devices.

[0055] Each function in the base station 10 and the terminal 20 is realized by loading a specific software (program) onto hardware such as a processor 1001, a memory device 1002, etc., so that the processor 1001 performs calculations, controls communications by the communication device 1004, and controls at least one of reading and writing of data in the memory device 1002 and the auxiliary memory device 1003.

[0056] The processor 1001 controls the entire computer by running, for example, an operating system. The processor 1001 may be configured as a central processing unit (CPU) including an interface with peripheral devices, a control device, an arithmetic unit, a register, etc. For example, the above-mentioned control unit 140, control unit 240, etc. may be realized by the processor 1001.

[0057] Moreover, the processor 1001 reads out a program (program code), a software module, data, or the like from at least one of the auxiliary storage device 1003 and the communication device 1004 to the storage device 1002, and executes various processes according to the program. As the program, a program that causes a computer to execute at least a part of the operations described in the above-mentioned embodiment is used. For example, the control unit 140 of the base station 10 shown in FIG. 8 may be realized by a control program stored in the storage device 1002 and operated by the processor 1001. Also, for example, the control unit 240 of the terminal 20 shown in FIG. 9 may be realized by a control program stored in the storage device 1002 and operated by the processor 1001. Although the above-mentioned various processes have been described as being executed by one processor 1001, they may be executed by two or more processors 1001 simultaneously or sequentially. The processor 1001 may be implemented by one or more chips. The program may be transmitted from a network via a telecommunication line.

[0058] The storage device 1002 is a computer-readable recording medium, and may be configured by at least one of, for example, a Read Only Memory (ROM), an Erasable Programmable ROM (EPROM), an Electrically Erasable Programmable ROM (EEPROM), a Random Access Memory (RAM), etc. The storage device 1002 may also be called a register, a cache, a main memory (primary storage device), etc. The storage device 1002 can store a program (program code), software modules, etc. that are executable to implement a communication method according to an embodiment of the present disclosure.

[0059] The auxiliary storage device 1003 is a computer-readable recording medium, and may be, for example, at least one of an optical disk such as a CD-ROM (Compact Disc ROM), a hard disk drive, a flexible disk, a magneto-optical disk (e.g., a compact disk, a digital versatile disk, a Blu-ray (registered trademark) disk), a smart card, a flash memory (e.g., a card, a stick, a key drive), a floppy (registered trademark) disk, a magnetic strip, etc. The above-mentioned storage medium may be, for example, a database, a server, or other suitable medium including at least one of the storage device 1002 and the auxiliary storage device 1003.

[0060] The communication device 1004 is hardware (transmission and reception device) for performing communication between computers via at least one of a wired network and a wireless network, and is also called, for example, a network device, a network controller, a network card, a communication module, etc. The communication device 1004 may be configured to include a high-frequency switch, a duplexer, a filter, a frequency synthesizer, etc., in order to realize at least one of Frequency Division Duplex (FDD) and Time Division Duplex (TDD). For example, a transmission and reception antenna, an amplifier unit, a transmission and reception unit, a transmission line interface, etc. may be realized by the communication device 1004. The transmission and reception unit may be implemented as a transmission unit and a reception unit that are physically or logically separated from each other.

[0061] The input device 1005 is an input device (e.g., a keyboard, a mouse, a microphone, a switch, a button, a sensor, etc.) that accepts input from the outside. The output device 1006 is an output device (e.g., a display, a speaker, an LED lamp, etc.) that performs output to the outside. The input device 1005 and the output device 1006 may be integrated into one device (e.g., a touch panel).

[0062] In addition, each device such as the processor 1001 and the storage device 1002 is connected by a bus 1007 for communicating information. The bus 1007 may be configured using a single bus, or may be configured using different buses between each device.

[0063] Furthermore, the base station 10 and the terminal 20 may be configured to include hardware such as a microprocessor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a programmable logic device (PLD), a field programmable gate array (FPGA), etc., and some or all of the functional blocks may be realized by the hardware. For example, the processor 1001 may be implemented using at least one of these pieces of hardware.

[0064] (Summary of the embodiment) As described above, according to an embodiment of the present invention, a base station is provided that includes a receiving unit that receives information indicating band combinations supported by the terminal from the terminal, a control unit that generates first information indicating all band combinations supported by the terminal including the band of the supported primary cell, and a transmitting unit that transmits the first information to a secondary node, wherein the receiving unit receives second information indicating a band combination used by the secondary node from all the band combinations, and the transmitting unit transmits the second information to the terminal.

[0065] With the above configuration, the MN notifies the SN of all band combinations including the bands of the supported PCell, and thus the number of selectable band combinations increases when the SN selects a band combination, thereby reducing the failure of setting the SCG. In other words, the probability of failure in setting the band combination during dual connectivity can be reduced.

[0066] The control unit may not limit the band combination based on the band of the supported secondary cell when generating the first information. With this configuration, the MN notifies the SN of all band combinations including the band of the supported PCell without applying other limitations, so that when the SN selects a band combination, the number of selectable band combinations increases, thereby reducing the failure of setting the SCG.

[0067] The control unit may not limit the band combination based on the parameters of each supported band when generating the first information. With this configuration, the MN notifies the SN of all band combinations including the bands of the PCell that the MN supports without applying other limitations, and thus the number of selectable band combinations increases when the SN selects a band combination, thereby reducing the failure of setting the SCG.

[0068] The control unit may generate first information indicating all band combinations including the band of the supported primary cell among the band combinations supported by the terminal only when setting up dual connectivity. With this configuration, the MN notifies the SN of all band combinations including the band of the PCell supported at the time of DC setup, so that when the SN selects a band combination, the number of selectable band combinations increases, thereby reducing the failure of setting up the SCG.

[0069] The control unit may limit a band combination based on a band of a supported secondary cell when generating the first information only when changing the already set up dual connectivity. With this configuration, when the MN changes the setting of the SN, the MN can reduce signaling overhead by limiting the band combination from the viewpoint of PCell and SCell.

[0070] Also, according to an embodiment of the present invention, there is provided a communication method in which a base station executes the following procedures: a receiving procedure for receiving information indicating band combinations supported by the terminal from the terminal; a control procedure for generating first information indicating all band combinations supported by the terminal, including the band of a supported primary cell; a transmitting procedure for transmitting the first information to a secondary node; a procedure for receiving second information indicating a band combination used by the secondary node, among all the band combinations, from the secondary node; and a procedure for transmitting the second information to the terminal.

[0071] With the above configuration, the MN notifies the SN of all band combinations including the bands of the supported PCell, and thus the number of selectable band combinations increases when the SN selects a band combination, thereby reducing the failure of setting the SCG. In other words, the probability of failure in setting the band combination during dual connectivity can be reduced.

[0072] (Supplementary embodiment) Although the embodiment of the present invention has been described above, the disclosed invention is not limited to such an embodiment, and those skilled in the art will understand various modifications, modifications, alternatives, replacements, and the like. Although the description has been given using specific numerical examples to facilitate understanding of the invention, unless otherwise specified, those numerical values ​​are merely examples and any appropriate values ​​may be used. The division of items in the above description is not essential to the present invention, and matters described in two or more items may be used in combination as necessary, and matters described in one item may be applied to matters described in another item (as long as there is no contradiction). The boundaries of functional units or processing units in the functional block diagram do not necessarily correspond to the boundaries of physical parts. The operations of multiple functional units may be physically performed by one part, or the operations of one functional unit may be physically performed by multiple parts. The order of the processing procedures described in the embodiment may be changed as long as there is no contradiction. For convenience of the processing description, the base station 10 and the terminal 20 have been described using functional block diagrams, but such devices may be realized by hardware, software, or a combination thereof. The software operated by the processor possessed by the base station 10 in accordance with an embodiment of the present invention and the software operated by the processor possessed by the terminal 20 in accordance with an embodiment of the present invention may each be stored in a random access memory (RAM), flash memory, read only memory (ROM), EPROM, EEPROM, register, hard disk (HDD), removable disk, CD-ROM, database, server or any other suitable storage medium.

[0073] In addition, the notification of information is not limited to the aspects / embodiments described in the present disclosure, and may be performed using other methods. For example, the notification of information may be performed by physical layer signaling (e.g., Downlink Control Information (DCI), Uplink Control Information (UCI)), higher layer signaling (e.g., Radio Resource Control (RRC) signaling, Medium Access Control (MAC) signaling), broadcast information (Master Information Block (MIB), System Information Block (SIB)), other signals, or a combination of these. In addition, the RRC signaling may be called an RRC message, and may be, for example, an RRC Connection Setup message, an RRC Connection Reconfiguration message, or the like.

[0074] Each aspect / embodiment described in the present disclosure may be applied to at least one of systems using LTE (Long Term Evolution), LTE-A (LTE-Advanced), SUPER 3G, IMT-Advanced, 4G (4th generation mobile communication system), 5G (5th generation mobile communication system), FRA (Future Radio Access), NR (new Radio), W-CDMA (registered trademark), GSM (registered trademark), CDMA2000, UMB (Ultra Mobile Broadband), IEEE 802.11 (Wi-Fi (registered trademark)), IEEE 802.16 (WiMAX (registered trademark)), IEEE 802.20, UWB (Ultra-WideBand), Bluetooth (registered trademark), and other suitable systems, and next-generation systems extended based on these. In addition, a combination of multiple systems (e.g., a combination of at least one of LTE and LTE-A and 5G, etc.) may be applied.

[0075] The steps, sequences, flow charts, etc. of each aspect / embodiment described herein may be reordered unless inconsistent. For example, the methods described in this disclosure present elements of various steps using an example order, and are not limited to the particular order presented.

[0076] In this specification, a specific operation performed by the base station 10 may be performed by its upper node in some cases. In a network consisting of one or more network nodes having the base station 10, it is clear that various operations performed for communication with the terminal 20 may be performed by at least one of the base station 10 and other network nodes other than the base station 10 (e.g., MME or S-GW, etc., but are not limited to these). Although the above example illustrates a case where there is one other network node other than the base station 10, the other network node may be a combination of multiple other network nodes (e.g., MME and S-GW).

[0077] The information or signals described in the present disclosure may be output from a higher layer (or a lower layer) to a lower layer (or a higher layer), or may be input / output via multiple network nodes.

[0078] The input and output information may be stored in a specific location (e.g., memory) or may be managed using a management table. The input and output information may be overwritten, updated, or added to. The output information may be deleted. The input information may be transmitted to another device.

[0079] In the present disclosure, the determination may be made based on a value represented by one bit (0 or 1), a Boolean value (true or false), or a numerical comparison (e.g., comparison with a predetermined value).

[0080] Software shall be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software modules, applications, software applications, software packages, routines, subroutines, objects, executable files, threads of execution, procedures, functions, etc., whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise.

[0081] Additionally, software, instructions, information, etc. may be transmitted or received over a transmission medium. For example, if the software is transmitted from a website, server, or other remote source using wired and / or wireless technologies (such as coaxial cable, fiber optic cable, twisted pair, Digital Subscriber Line (DSL)), and / or wireless technologies (such as infrared, microwave, etc.), then these wired and / or wireless technologies are included within the definition of transmission media.

[0082] The information, signals, etc. described in this disclosure may be represented using any of a variety of different technologies. For example, the data, instructions, commands, information, signals, bits, symbols, chips, etc. that may be referred to throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or magnetic particles, optical fields or photons, or any combination thereof.

[0083] In addition, the terms described in this disclosure and the terms necessary for understanding this disclosure may be replaced with terms having the same or similar meanings. For example, at least one of a channel and a symbol may be a signal (signaling). Also, a signal may be a message. Also, a component carrier (CC) may be called a carrier frequency, a cell, a frequency carrier, etc.

[0084] As used in this disclosure, the terms "system" and "network" are used interchangeably.

[0085] In addition, the information, parameters, etc. described in the present disclosure may be represented using absolute values, may be represented using relative values ​​from a predetermined value, or may be represented using other corresponding information. For example, a radio resource may be indicated by an index.

[0086] The names used for the above-mentioned parameters are not limiting in any way. Moreover, the formulas using these parameters may differ from those explicitly disclosed in this disclosure. The various channels (e.g., PUCCH, PDCCH, etc.) and information elements may be identified by any suitable names, and therefore the various names assigned to these various channels and information elements are not limiting in any way.

[0087] In this disclosure, terms such as "base station (BS)", "radio base station", "base station", "fixed station", "NodeB", "eNodeB (eNB)", "gNodeB (gNB)", "access point", "transmission point", "reception point", "transmission / reception point", "cell", "sector", "cell group", "carrier", "component carrier", etc. may be used interchangeably. A base station may also be referred to by terms such as a macro cell, a small cell, a femto cell, a pico cell, etc.

[0088] A base station can accommodate one or more (e.g., three) cells. When a base station accommodates multiple cells, the entire coverage area of ​​the base station can be partitioned into multiple smaller areas, and each smaller area can also be provided with communication services by a base station subsystem (e.g., a small indoor base station (RRH: Remote Radio Head)). The term "cell" or "sector" refers to a part or the entire coverage area of ​​a base station and / or a base station subsystem that provides communication services in this coverage.

[0089] In this disclosure, the terms "Mobile Station (MS)", "user terminal", "User Equipment (UE)", "terminal", etc. may be used interchangeably.

[0090] A mobile station may also be referred to by those skilled in the art as a subscriber station, mobile unit, subscriber unit, wireless unit, remote unit, mobile device, wireless device, wireless communication device, remote device, mobile subscriber station, access terminal, mobile terminal, wireless terminal, remote terminal, handset, user agent, mobile client, client, or some other suitable terminology.

[0091] At least one of the base station and the mobile station may be called a transmitting device, a receiving device, a communication device, etc. At least one of the base station and the mobile station may be a device mounted on a moving body, the moving body itself, etc. The moving body may be a vehicle (e.g., a car, an airplane, etc.), an unmanned moving body (e.g., a drone, an autonomous vehicle, etc.), or a robot (manned or unmanned). At least one of the base station and the mobile station may include a device that does not necessarily move during communication operation. For example, at least one of the base station and the mobile station may be an IoT (Internet of Things) device such as a sensor.

[0092] Furthermore, the base station in the present disclosure may be read as a user terminal. For example, each aspect / embodiment of the present disclosure may be applied to a configuration in which communication between a base station and a user terminal is replaced with communication between a plurality of terminals 20 (which may be called, for example, D2D (Device-to-Device) or V2X (Vehicle-to-Everything)). In this case, the terminal 20 may be configured to have the functions of the base station 10 described above. Furthermore, terms such as "uplink" and "downlink" may be read as terms corresponding to terminal-to-terminal communication (for example, "side"). For example, an uplink channel, a downlink channel, etc. may be read as a side channel.

[0093] Similarly, a user terminal in the present disclosure may be read as a base station. In this case, the base station may be configured to have the functions of the above-mentioned user terminal.

[0094] As used in this disclosure, the terms "determining" and "determining" may encompass a wide variety of actions. "Determining" and "determining" may include, for example, judging, calculating, computing, processing, deriving, investigating, looking up, search, inquiry (e.g., searching in a table, database, or other data structure), ascertaining, and the like. "Determining" and "determining" may also include receiving (e.g., receiving information), transmitting (e.g., sending information), input, output, accessing (e.g., accessing data in a memory), and the like. In addition, "judgment" and "decision" can include considering resolving, selecting, choosing, establishing, comparing, etc., to be a "judgment" or "decision." In other words, "judgment" and "decision" can include considering some action to be a "judgment" or "decision." In addition, "judgment" can be interpreted as "assuming," "expecting," "considering," etc.

[0095] The terms "connected," "coupled," or any variation thereof, refer to any direct or indirect connection or coupling between two or more elements, and may include the presence of one or more intermediate elements between two elements that are "connected" or "coupled" to each other. The coupling or connection between elements may be physical, logical, or a combination thereof. For example, "connected" may be read as "access." As used in this disclosure, two elements may be considered to be "connected" or "coupled" to each other using at least one of one or more wires, cables, and printed electrical connections, as well as electromagnetic energy having wavelengths in the radio frequency range, microwave range, and optical (both visible and invisible) range, as some non-limiting and non-exhaustive examples.

[0096] The reference signal may be abbreviated as RS (Reference Signal) and may be called a pilot depending on the applicable standard.

[0097] As used in this disclosure, the phrase "based on" does not mean "based only on," unless expressly stated otherwise. In other words, the phrase "based on" means both "based only on" and "based at least on."

[0098] Any reference to an element using a designation such as "first," "second," etc., used in this disclosure does not generally limit the quantity or order of those elements. These designations may be used in this disclosure as a convenient method of distinguishing between two or more elements. Thus, a reference to a first and a second element does not imply that only two elements may be employed or that the first element must precede the second element in some way.

[0099] The "means" in the configuration of each of the above devices may be replaced with "part," "circuit," "device," etc.

[0100] When the terms "include," "including," and variations thereof are used in this disclosure, these terms are intended to be inclusive, similar to the term "comprising." Further, when used in this disclosure, the term "or" is not intended to be an exclusive or.

[0101] A radio frame may be composed of one or more frames in the time domain. Each of the one or more frames in the time domain may be called a subframe. A subframe may further be composed of one or more slots in the time domain. A subframe may have a fixed time length (e.g., 1 ms) that is independent of numerology.

[0102] The numerology may be communication parameters that apply to the transmission and / or reception of a signal or channel, such as, for example, at least one of a subcarrier spacing (SCS), a bandwidth, a symbol length, a cyclic prefix length, a transmission time interval (TTI), a number of symbols per TTI, a radio frame structure, a particular filtering operation that the transceiver performs in the frequency domain, a particular windowing operation that the transceiver performs in the time domain, etc.

[0103] A slot may be composed of one or more symbols (such as an Orthogonal Frequency Division Multiplexing (OFDM) symbol, a Single Carrier Frequency Division Multiple Access (SC-FDMA) symbol, etc.) in the time domain. A slot may be a time unit based on numerology.

[0104] A slot may include multiple minislots. Each minislot may be composed of one or multiple symbols in the time domain. A minislot may also be called a subslot. A minislot may be composed of fewer symbols than a slot. A PDSCH (or PUSCH) transmitted in a time unit larger than a minislot may be called PDSCH (or PUSCH) mapping type A. A PDSCH (or PUSCH) transmitted using a minislot may be called PDSCH (or PUSCH) mapping type B.

[0105] A radio frame, a subframe, a slot, a minislot, and a symbol each represent a time unit for transmitting a signal. The radio frame, the subframe, the slot, the minislot, and the symbol may each be referred to by a different name.

[0106] For example, one subframe may be called a transmission time interval (TTI), multiple consecutive subframes may be called a TTI, or one slot or one minislot may be called a TTI. That is, at least one of the subframe and the TTI may be a subframe (1 ms) in the existing LTE, a period shorter than 1 ms (for example, 1-13 symbols), or a period longer than 1 ms. Note that the unit expressing the TTI may be called a slot, a minislot, or the like, instead of a subframe.

[0107] Here, TTI refers to, for example, the minimum time unit for scheduling in wireless communication. For example, in an LTE system, a base station performs scheduling to allocate wireless resources (such as frequency bandwidth and transmission power that can be used by each terminal 20) to each terminal 20 in TTI units. Note that the definition of TTI is not limited to this.

[0108] The TTI may be a transmission time unit for a channel-encoded data packet (transport block), a code block, a code word, etc., or may be a processing unit for scheduling, link adaptation, etc. When a TTI is given, the time interval (e.g., the number of symbols) in which a transport block, a code block, a code word, etc. are actually mapped may be shorter than the TTI.

[0109] In addition, when one slot or one minislot is called TTI, one or more TTIs (i.e., one or more slots or one or more minislots) may be the minimum time unit of scheduling. Also, the number of slots (minislots) constituting the minimum time unit of scheduling may be controlled.

[0110] A TTI having a time length of 1 ms may be called a normal TTI (TTI in LTE Rel. 8-12), a normal TTI, a long TTI, a normal subframe, a normal subframe, a long subframe, a slot, etc. A TTI shorter than a normal TTI may be called a shortened TTI, a short TTI, a partial or fractional TTI, a shortened subframe, a short subframe, a minislot, a subslot, a slot, etc.

[0111] In addition, a long TTI (e.g., a normal TTI, a subframe, etc.) may be interpreted as a TTI having a time length exceeding 1 ms, and a short TTI (e.g., a shortened TTI, etc.) may be interpreted as a TTI having a TTI length shorter than the TTI length of a long TTI and equal to or greater than 1 ms.

[0112] A resource block (RB) is a resource allocation unit in the time domain and the frequency domain, and may include one or more consecutive subcarriers in the frequency domain. The number of subcarriers included in an RB may be the same regardless of the numerology, for example, 12. The number of subcarriers included in an RB may be determined based on the numerology.

[0113] In addition, the time domain of the RB may include one or more symbols and may be one slot, one minislot, one subframe, or one TTI in length. Each of one TTI, one subframe, etc. may be composed of one or more resource blocks.

[0114] Note that one or more RBs may be called a physical resource block (PRB), a sub-carrier group (SCG), a resource element group (REG), a PRB pair, an RB pair, or the like.

[0115] Furthermore, a resource block may be composed of one or more resource elements (REs). For example, one RE may be a radio resource region of one subcarrier and one symbol.

[0116] A Bandwidth Part (BWP), which may also be referred to as a fractional bandwidth, may represent a subset of contiguous common resource blocks (RBs) for a numerology on a carrier, where the common RBs may be identified by an index of the RBs relative to a common reference point of the carrier. PRBs may be defined in a BWP and numbered within the BWP.

[0117] The BWP may include a BWP for UL (UL BWP) and a BWP for DL ​​(DL BWP). For the terminal 20, one or more BWPs may be set within one carrier.

[0118] At least one of the configured BWPs may be active, and the terminal 20 may not expect to transmit or receive a predetermined signal / channel outside the active BWP. Note that the terms "cell", "carrier", and the like in this disclosure may be replaced with "BWP".

[0119] The above-mentioned structures of radio frames, subframes, slots, minislots, symbols, etc. are merely examples. For example, the number of subframes included in a radio frame, the number of slots per subframe or radio frame, the number of minislots included in a slot, the number of symbols and RBs included in a slot or minislot, the number of subcarriers included in an RB, the number of symbols in a TTI, the symbol length, the cyclic prefix (CP) length, etc. may be changed in various ways.

[0120] In this disclosure, where articles have been added due to translation, such as a, an, and the in English, the disclosure may include that the nouns following these articles are in the plural form.

[0121] In the present disclosure, the term "A and B are different" may mean "A and B are different from each other." The term may also mean "A and B are each different from C." Terms such as "separate" and "coupled" may also be interpreted in the same way as "different."

[0122] Each aspect / embodiment described in this disclosure may be used alone, in combination, or switched according to execution. In addition, notification of predetermined information (e.g., notification that "X is the case") is not limited to being done explicitly, but may be done implicitly (e.g., not notifying the predetermined information).

[0123] Although the present disclosure has been described in detail above, it is clear to those skilled in the art that the present disclosure is not limited to the embodiments described in the present disclosure. The present disclosure can be implemented in modified and altered forms without departing from the spirit and scope of the present disclosure as defined by the claims. Therefore, the description of the present disclosure is intended to be illustrative and does not have any limiting meaning on the present disclosure.

[0124] <Additional Notes> The above-described embodiment can be further described as follows.

[0125] (Appendix 1) A receiving unit that receives information indicating a band combination supported by a terminal from the terminal; A control unit that generates first information indicating all band combinations including a band of a primary cell supported by the terminal among band combinations supported by the terminal; a transmission unit that transmits the first information to a secondary node, The receiving unit receives, from the secondary node, second information indicating a band combination used by the secondary node among all the band combinations, The transmission unit is a base station that transmits the second information to the terminal.

[0126] (Appendix 2) The base station of claim 1, wherein the control unit does not limit a band combination based on a band of a supported secondary cell when generating the first information.

[0127] (Appendix 3) The base station of claim 1, wherein the control unit does not limit a band combination based on parameters of each supported band when generating the first information.

[0128] (Appendix 4) The base station of supplementary note 1, wherein the control unit generates first information indicating all band combinations including the band of the primary cell supported by the terminal, among the band combinations supported by the terminal, only when setting up dual connectivity.

[0129] (Appendix 5) The base station of Supplementary Note 1, wherein the control unit limits the band combination based on the band of a supported secondary cell when generating the first information only when changing the already set up dual connectivity.

[0130] (Appendix 6) A receiving procedure for receiving information indicating a band combination supported by a terminal from the terminal; A control procedure for generating first information indicating all band combinations including a band of a primary cell supported by the terminal among band combinations supported by the terminal; a transmitting step of transmitting the first information to a secondary node; receiving second information indicating a band combination used by the secondary node from the secondary node among all the band combinations; and a procedure of transmitting the second information to the terminal, the procedure being performed by a base station. [Explanation of symbols]

[0131] 10 base station 110 Transmitter 120 Receiving unit 130 Setting section 140 Control section 20 Terminals 210 Transmitter 220 Receiving unit 230 Setting section 240 Control Unit 30 Core Network 1001 Processor 1002 Storage device 1003 Auxiliary storage device 1004 Communication equipment 1005 Input Device 1006 Output device

Claims

1. A first base station performing dual connectivity with a second base station, A control unit that determines a candidate list of band combinations to be used for dual connectivity based on a band of a primary cell in the first base station; a transmitter for transmitting the candidate list to a second base station; a receiving unit that receives, from the second base station, information indicating a band combination selected by the second base station from the candidate list; The transmission unit transmits a message for setting a cell of the second base station to a terminal, The receiving unit is a base station that receives a response to the message from the terminal.

2. A communication system including a first base station, a second base station, and a terminal that perform dual connectivity, The first base station A control unit that determines a candidate list of band combinations to be used for dual connectivity based on a band of a primary cell in the first base station; a transmitter for transmitting the candidate list to the second base station; a receiving unit that receives, from the second base station, information indicating a band combination selected by the second base station from the candidate list; The transmission unit transmits a message for setting a cell of the second base station to the terminal; The receiving unit receives a response to the message from the terminal; The second base station a receiving unit for receiving the candidate list from the first base station; a transmitter that transmits information indicating a band combination selected by the second base station from the candidate list to the first base station, The terminal includes: a receiving unit that receives a message for setting a cell of the second base station from the first base station; a transmitter for transmitting a response to the message to the first base station.

3. 1. A communication method performed by a first base station performing dual connectivity with a second base station, comprising: determining a candidate list of band combinations to be used for dual connectivity based on a band of a primary cell in the first base station; transmitting the candidate list to the second base station; receiving information indicating a band combination selected by the second base station from the candidate list from the second base station; transmitting a message for setting up a cell of the second base station to a terminal; and receiving a response to the message from the terminal, the first base station executing the procedure.

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