Base station, terminal, and communication method

Abstract

The base station has a transmission unit that transmits a message requesting a report of terminal capability to a terminal in a first RAT (Radio access technology), a reception unit that receives a message reporting terminal capability from the terminal in the first RAT, the terminal capability including a capability related to the first RAT, a capability related to a second RAT, a capability related to dual connectivity using the first RAT and the second RAT, and a control unit that decides a candidate list of band combinations used in the dual connectivity based on the capability related to the first RAT, the transmission unit transmitting the candidate list to a base station in the second RAT, and the reception unit receiving information from the base station in the second RAT, the information indicating an appropriate band combination selected from the candidate list by the base station in the second RAT based on the capability related to the second RAT.

Description

Technical Field

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

[0002] In NR (New Radio) (also known as "5G"), which is the successor system to LTE (Long Term Evolution), technologies that meet the requirements of large-capacity systems, high data transmission speeds, low latency, simultaneous connection of a large number of terminals, low costs, and power saving are being studied (for example, non-patent document 1).

[0003] In an LTE or NR system, the network queries the UE (User Equipment) to obtain information related to the UE's radio access capabilities (e.g., Non-Patent Document 2). The UE's radio access capabilities include, for example, the maximum supported data rate, the total layer 2 buffer size, the supported frequency band combinations, MIMO (Multiple-Input and Multiple-Output) parameters, PDCP (Packet Data Convergence Protocol) layer parameters, RLC (Radio Link Control) layer parameters, MAC (Medium Access Control) layer parameters, or physical layer parameters (e.g., Non-Patent Document 3).

[0004] Prior art literature

[0005] Non-patent literature

[0006] Non-Patent Document 1: 3GPP TS 38.300 V16.2.0 (2020-07)

[0007] Non-Patent Document 2: 3GPP TS 38.331 V16.1.0 (2020-07)

[0008] Non-Patent Document 3: 3GPP TS 38.306 V16.1.0 (2020-07) Summary of the Invention

[0009] Problems to be solved by the invention

[0010] In the related art, when performing communication based on dual connectivity of a plurality of RATs (Radio access technologies), UE capability involved in the frequency bands of the respective plurality of RATs is judged individually, and sometimes the performance is not maximized as a whole.

[0011] The present application has been achieved in view of the above problems, and aims to improve performance at the time of dual connectivity in a wireless communication system.

[0012] Means for solving the problems

[0013] According to the disclosed technology, a base station is provided with a transmission unit that transmits a message requesting a report of terminal capability to a terminal in a first RAT (Radio access technology), a reception unit that receives a message reporting terminal capability from the terminal in the first RAT, the terminal capability including capability involved in the first RAT, capability involved in a second RAT, and capability involved in dual connectivity using the first RAT and the second RAT, and a control unit that decides a candidate list of frequency band combinations used in the dual connectivity based on the capability involved in the first RAT, the transmission unit transmitting the candidate list to a base station in the second RAT,

[0014] The reception unit receives information from the base station in the second RAT, the information indicating an appropriate frequency band combination selected from the candidate list by the base station in the second RAT based on the capability involved in the second RAT.

[0015] Effects of the invention

[0016] According to the disclosed technology, in a wireless communication system, it is possible to improve performance at the time of dual connectivity. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 is a diagram showing a structure example of a network architecture in an embodiment of the present application.

[0018] Figure 2 is a diagram showing a structure example of a wireless communication system in an embodiment of the present application.

[0019] Figure 3 is a timing chart for explaining an example (1) of a communication setting.

[0020] Figure 4 is a diagram showing an example of terminal capability involved in a frequency band combination.

[0021] Figure 5 is a timing chart for explaining an example (2) of a communication setting.

[0022] Figure 6 is a flowchart for explaining an example (1) of the frequency band combination selection in the embodiment of the present application.

[0023] Figure 7 is a flowchart for explaining an example (2) of the frequency band combination selection in the embodiment of the present application.

[0024] Figure 8 is a diagram showing an example of the functional structure of the base station 10 in the embodiment of the present application.

[0025] Figure 9 is a diagram showing an example of the functional structure of the terminal 20 in the embodiment of the present application.

[0026] Figure 10 is a diagram showing an example of the hardware structure of the base station 10 or the terminal 20 in the embodiment of the present application. DETAILED DESCRIPTION

[0027] Hereinafter, the embodiment of the present application will be explained with reference to the attached drawings. In addition, the embodiment explained below is an example, and the application of the embodiment of the present application is not limited to the following embodiment.

[0028] In the operation of the wireless communication system of the embodiment of the present application, the existing technology is appropriately used. However, the existing technology is, for example, the existing LTE, but is not limited to the existing LTE. Furthermore, the term "LTE" used in the present specification has a broad meaning including LTE-Advanced and the mode after LTE-Advanced (example: NR) as long as not particularly specified.

[0029] Furthermore, in the following description of the embodiments of the present application, 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), PUSCH (Physical Uplink Shared Channel), and the like, which are used in the existing LTE, are used. This is for the sake of convenience in description, and the same signals, functions, and the like can also be referred to by other names. Furthermore, the above terms in the NR correspond to NR-SS, NR-PSS, NR-SSS, NR-PBCH, NR-PRACH, NR-PDCCH, NR-PDSCH, NR-PUCCH, NR-PUSCH, and the like. However, even in the NR, the signals used are not necessarily explicitly described as "NR-".

[0030] Furthermore, in the embodiments of the present application, the Duplex method can be either a TDD (Time Division Duplex) method or an FDD (Frequency Division Duplex) method, or can also be a method other than these (for example, Flexible Duplex, and the like).

[0031] Furthermore, in the embodiments of the present application, the wireless parameters and the like are "configured" either by being pre-configured with specific values, or by being configured with wireless parameters notified from the base station 10 or the terminal 20.

[0032] Figure 1 FIG. 1 is a diagram showing a structure example of a network architecture in the embodiments of the present application. As shown in FIG. 1, the network architecture in the embodiments of the present application includes a core network 100 and a radio access network 200. The core network 100 is connected to a radio access network 200 via an NG2 interface. Figure 1As shown, the wireless network architecture in the embodiment of the present application contains 4G-CU, 4G-RU (Remote Unit, Remote Radio Station), EPC (Evolved Packet Core), and the like on the LTE-Advanced side. The wireless network architecture in the embodiment of the present application contains 5G-CU, 5G-DU, and the like on the 5G side.

[0033] As shown, the 4G-CU contains RRC (Radio Resource Control), PDCP (Packet Data Convergence Protocol), RLC (Radio Link Control), MAC (Medium Access Control), layers up to L1 (Layer 1, PHY layer or physical layer), and is connected with the 4G-RU via CPRI (Common Public Radio Interface). The network node containing the 4G-CU and the 4G-RU is referred to as eNB. Figure 1

[0034] On the other hand, on the 5G side, as shown, the 5G-CU contains the RRC layer, is connected with the 5G-DU via the FH (Flonthaul) interface, and is connected with the 5GC (5G Core Network) via the NG interface. Further, the 5G-CU is connected with the 4G-CU through the X2 interface. The PDCP layer in the 4G-CU becomes a point of combination or separation in the case of performing DC (Dual Connectivity) of 4G-5G, that is, EN-DC (E-UTRA-NR Dual Connectivity). The network node containing the 5G-CU and the 5G-DU is referred to as gNB. Further, the 5G-CU can also be referred to as gNB-CU, and the 5G-DU can also be referred to as gNB-DU. Figure 1

[0035] Further, as shown, CA (Carrier Aggregation) is performed among the 4G-RUs, and DC is performed in the 4G-RU and the 5G-DU. In addition, although not shown, the UE (User Equipment) is wirelessly connected via the RF of the 4G-RU or the 5G-DU, and transmits and receives packets. Figure 1

[0036] In addition, Figure 1 ​​​The wireless network architecture of LTE-NR's DC, namely EN-DC (E-UTRA-NR Dual Connectivity), is shown. However, the same wireless network architecture can be used when the 4G-CU is separated into CU-DU or when NR is used independently. When the 4G-CU is separated into CU-DU, the functions involved in the RRC layer and the PDCP layer can be transferred to the 4G-CU, and the RLC layer and below can be included in the 4G-DU. In addition, the data rate of CPRI can also be reduced by CU-DU separation.

[0037] In addition, multiple 5G-DUs can also be connected to the 5G-CU. In addition, NR-DC (NR-NR Dual Connectivity) can be performed by connecting the UE to multiple 5G-CUs, and NR-DC can be performed by connecting the UE to multiple 5G-DUs and a single 5G-CU. In addition, the 5G-CU can be directly connected to the EPC without going through the 4G-CU, or the 4G-CU can be directly connected to the 5GC without going through the 5G-CU.

[0038] also, Figure 1 The wireless network architecture for EN-DC is shown, but is not limited to this. For example, the wireless network architecture can be NR-DC or NE-DC (NR-EUTRA Dual Connectivity), or other wireless network architectures can be used. Furthermore, the wireless network architecture does not need to be used in DC and can be used independently.

[0039] Figure 2 FIG is a diagram showing a configuration example of a wireless communication system in an embodiment of the present invention. Figure 2 As shown in FIG, the wireless communication system in the embodiment of the present invention includes a base station 10 and a terminal 20. Figure 2 In the figure, one base station 10 and one terminal 20 are shown, but this is an example, and there may be multiple base stations 10 and multiple terminals 20 respectively.

[0040] 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 the wireless signal are defined by the time domain and the frequency domain. The time domain can also be defined by the number of OFDM symbols, and the frequency domain can also be defined by the number of subcarriers or resource blocks. The base station 10 sends synchronization signals and system information to the terminal 20. Synchronization signals are, for example, NR-PSS and NR-SSS. System information is sent, for example, via NR-PBCH, also known as broadcast information. Figure 2As shown, the base station 10 transmits a control signal or data to the terminal 20 through DL (Downlink), and receives a control signal or data from the terminal 20 through UL (Uplink). Either of the base station 10 and the terminal 20 can perform beamforming and perform transmission and reception of a signal. Further, either of the base station 10 and the terminal 20 can apply MIMO (Multiple Input Multiple Output) based communication to DL or UL. Further, both of the base station 10 and the terminal 20 can perform communication via a PCell (Primary Cell) and an SCell (Secondary Cell) based on CA (Carrier Aggregation).

[0041] The terminal 20 is a communication device having a wireless communication function such as a smartphone, a mobile phone, a tablet, a wearable terminal, a communication module for M2M (Machine-to-Machine), and the like. As shown, the terminal 20 receives a control signal or data from the base station 10 through DL, and transmits a control signal or data to the base station 10 through UL, thereby utilizing various communication services provided by a wireless communication system. Figure 2

[0042] Here, in 5G-NSA (Non stand alone) that is non-standalone use of 5G, a band combination of EN-DC (EN-DC band combination) is specified as follows: based on the EN-DC band combination capability (UE-MRDC-Capability, UE-EUTRA-Capability, UE-NR-Capability) received by the base station 10 as an eNB from the terminal 20, the base station 10 as a gNB is prompted to select a candidate of the EN-DC band combination as an information element allowedBC-ListMRDC, and the gNB notifies the eNB of the selected EN-DC band combination in an information element selectedBandCombination. The EN-DC band combination indicates a band combination in communication in which EN-DC is applied.

[0043] Figure 3 is a timing chart for explaining an example (1) of a communication setting. In Figure 3 ​In step S1 shown, the base station 10A as an eNB transmits a "UECapabilityEnquiry" as an RRC message, that is, an inquiry of UE capability, to the terminal 20. In subsequent step S2, the terminal 20 transmits a "UECapabilityInformation" as an RRC message, that is, a report of UE capability, to the base station 10A for the UE capability designated by the received "UECapabilityEnquiry". The "UECapabilityInformation" contains the UE capability supported by the terminal 20. The base station 10A determines the supported UE capability based on the received "UECapabilityInformation" and applies to the wireless communication with the terminal 20.

[0044] For example, the "UECapabilityInformation" contains EN-DC band combination capability (UE-MRDC-Capability, UE-EUTRA-Capability, UE-NR-Capability). In the "UE-MRDC-Capability", EN-DC band combination is set and referred to by the base station 10A as an eNB and the base station 10B as a gNB. In the "UE-EUTRA-Capability", the bandwidth, the number of layers, and the modulation scheme of the LTE unit are set and referred to by the base station 10A as an eNB. In the "UE-NR-Capability", the bandwidth, the number of layers, and the modulation scheme of the NR unit are set and referred to by the base station 10B as a gNB.

[0045] As described above, in the EN-DC band combination capability, there are the capability of the LTE unit and the capability of the NR unit. The detailed capability (bandwidth and number of layers) of the LTE unit is specified in an information element "featureSetsEUTRA" contained in the "UE-EUTRA-Capability" referred to by the base station 10A as an eNB. The detailed capability (bandwidth and number of layers) of the NR unit is specified in an information element "featureSets" contained in the "UE-NR-Capability" referred to by the base station 10B as a gNB. On the standard specification, the eNB does not need to interpret and set the "UE-NR-Capability", and the gNB does not need to interpret and set the "UE-EUTRA-Capability".

[0046] In the subsequent step S3, the base station 10A transmits, via the X2 interface, an "SgNB Addition Request" to the base station 10B as a gNB. The "SgNB Addition Request" contains the information element "CG-Configinfo" of RRC and "allowedBC-ListMRDC".

[0047] The "allowedBC-ListMRDC" contains a list of indices that refer to the EN-DC band combinations contained in the "UE-MRDC-Capability" selected from the band combinations of the secondary cell group permitted to be selected in the secondary gNB.

[0048] Further, the "CG-Configinfo" contains the information element "eutra-CapabilityInfo". The "UE-MRDC-Capability" and the "UE-NR-Capability" acquired from the terminal 20 are set in the "eutra-CapabilityInfo".

[0049] In the subsequent step S4, the base station 10B transmits, via the X2 interface, an "SgNB Addition Request Acknowledge" to the base station 10A. The "SgNB Addition Request Acknowledge" contains the information element "CG-Config" of RRC and "selectedbandCombination".

[0050] The "selectedbandCombination" indicates the index of the EN-DC band combination selected by the secondary gNB.

[0051] Subsequently, the base station 10A and the base station 10B can also perform the communication with the terminal 20 applying the EN-DC using the EN-DC band combination selected by the base station 10B.

[0052] Figure 4 is a diagram showing an example of the terminal capability involved in the band combination. As Figure 4As shown, the "UE-MRDC-Capability" referenced by the eNB and gNB corresponds to "Band 1", "Band 3", "Band 19", "Band 21", "Band 28", and "n78" in the example EN-DC band combination "BC1". Furthermore, the "UE-MRDC-Capability" corresponds to "Band 1", "Band 3", and "n78" in the example EN-DC band combination "BC2".

[0053] like Figure 4 As shown, the "UE-EUTRA-Capability" referenced by the eNB but not by the gNB corresponds to "2L," "4L," "2L," "2L," and "2L" in the example EN-DC band combination "BC1." 2L indicates two layers, and 4L indicates four layers. Furthermore, the "UE-EUTRA-Capability" corresponds to "2L" and "4L" in the example EN-DC band combination "BC2."

[0054] like Figure 4 As shown, the "UE-NR-Capability" referenced by the gNB but not by the eNB corresponds to "(2L)(40MHz)" in the example of the EN-DC band combination "BC1". In addition, the "UE-NR-Capability" corresponds to "(4L)(100MHz)" in the example of the EN-DC band combination "BC2".

[0055] Here, the EN-DC band combination in the terminal 20 is managed within the overall bandwidth (eg, number of CCs) and number of layers of the terminal 20 due to signal processing capabilities. For example, the following EN-DC band combinations 1) and 2) are assumed to exist.

[0056] 1) LTE has more bandwidth (number of CCs) and layers, while NR has less bandwidth (number of CCs) and layers.

[0057] 2) LTE has less bandwidth (number of CCs) and layers, while NR has more bandwidth (number of CCs) and layers.

[0058] Therefore, it is necessary to comprehensively determine the possible configurations of the LTE and NR units to select the EN-DC band combination. On the other hand, if the eNB only sets the optimal EN-DC band combination from the LTE perspective as "allowedBC-ListMRDC", the gNB may only be notified of the unselectable band combination and be unable to configure EN-DC.

[0059] Figure 5is a timing chart for explaining an example (2) of a communication setting. In a case where the bandwidth of the NR unit is a bandwidth that the gNB does not use, it becomes an EN-DC-unsettable frequency band combination. For example, the terminal 20 supports the following 1) and 2) of the EN-DC frequency band combination as shown in Table 1, and the network uses NR with a 100 MHz bandwidth.

[0060] 1) LTE5CC + NR (40 MHz bandwidth)

[0061] 2) LTE2CC + NR (100 MHz bandwidth)

[0062] [Table 1]

[0063] AllowedBC-ListMRDC LTE NR #1 LTE-5CC NR (40 MHz bandwidth) #2 LTE2CC NR (100 MHz bandwidth)

[0064] Here, in a case where the base station 10A as the eNB sets only the EN-DC frequency band combination of the above 1) of LTE5CC to "allowedBC-ListMRDC" and transmits it to the base station 10B as the gNB via the X2 interface in step S11 shown in Figure 5 Figure 5 As shown in step S12, "SgNB Addition Request Reject" (a secondary gNB addition request rejection response) is transmitted from the base station 10B to the base station 10A via the X2 interface.

[0065] As described above, in the EN-DC frequency band combinations shown in the above 1) and 2), the base station 10A does not refer to the information of NR (40 MHz bandwidth) and NR (100 MHz bandwidth).

[0066] On the other hand, as another example, the terminal 20 supports the following 1) to 3) of the EN-DC frequency band combination as shown in Table 2, the area quality status of LTE is LTE 1.7 GHz superior to LTE 1.5 GHz, and the NR side is used with a 100 MHz bandwidth.

[0067] 1) LTE5CC + NR (40 MHz bandwidth)

[0068] 2) LTE2GHz (20 MHz bandwidth) + LTE1.5GHz (15 MHz bandwidth) + NR3.7GHz (100 MHz bandwidth)

[0069] 3) LTE2GHz (20 MHz bandwidth) + LTE1.7GHz (20 MHz bandwidth) + NR3.7GHz (100 MHz bandwidth)

[0070] ​[Table 2]

[0071]

[0072]

[0073] In a case where the base station 10A as the eNB does not range-reduce from the viewpoint of the PCell on the LTE side in the EN-DC band combination, the base station 10B as the gNB decides the EN-DC band combination only with reference to the NR unit, and thus the EN-DC band combination that takes into account the capability of the LTE unit is not sometimes decided.

[0074] In the example described above in which 1) to 3) are notified to the base station 10B via "allowedBC-ListMRDC" in step S11, the NR side is operated with a 100 MHz bandwidth, and thus 1) of 40 MHz bandwidth is out of the selection target in the base station 10B. Further, 2) and 3) have the same capability on the NR side, and thus the base station 10B is expected to select 3) that has a wider total bandwidth on the LTE side and has good area quality. However, since the base station 10B does not refer to the information on the LTE side, it is possible that 3) is not selected. That is, the base station 10B can select the EN-DC band combination of 2) that has a worse throughput than 3).

[0075] As described above, among the EN-DC band combinations of 1) to 3) described above, the base station 10B does not refer to the information on LTE 5CC, LTE 2 GHz (20 MHz bandwidth) + LTE 1.5 GHz (15 MHz bandwidth), and LTE 2 GHz (20 MHz bandwidth) + LTE 1.7 GHz (20 MHz bandwidth).

[0076] Therefore, for the EN-DC band combinations notified to the gNB as resolution candidates, the following operations can also be defined in the eNB and the gNB.

[0077] The eNB does not range-reduce except from the viewpoint of the PCell on the LTE side in "allowedBC-ListMRDC" notified to the gNB, but sets a list in which the order of the EN-DC band combination that is the best from the viewpoint of the LTE unit alone is set.

[0078] The gNB selects the EN-DC band combination from the list of "allowedBC-ListMRDC" from the viewpoint of the NR unit. In a case where the capabilities of the NR units are the same, the EN-DC band combination that is earlier in the order of the list is selected.

[0079] Figure 6is a flowchart for explaining an example (1) of the band combination selection in the embodiment of the present application. In step S21, the eNB does not perform the range narrowing other than the LTE side PCell viewpoint in the information element "allowedBC-ListMRDC" notified to the gNB, but sets the EN-DC band combination order from the LTE unit viewpoint as optimum.

[0080] As an example, the terminal 20 supports the EN-DC band combinations of 1) - 3) shown below, and the area quality status of LTE is LTE 1.7 GHz superior to LTE 1.5 GHz, and the NR side is applied with 100 MHz bandwidth.

[0081] 1) LTE 5CC + NR (40 MHz bandwidth)

[0082] 2) LTE 2 GHz (20 MHz bandwidth) + LTE 1.5 GHz (15 MHz bandwidth) + NR 3.7 GHz (100 MHz bandwidth)

[0083] 3) LTE 2 GHz (20 MHz bandwidth) + LTE 1.7 GHz (20 MHz bandwidth) + NR 3.7 GHz (100 MHz bandwidth)

[0084] In step S21, the list of the EN-DC band combinations of 1) 3) 2) in the order of high performance from the LTE side viewpoint is set in "allowedBC-ListMRDC" as shown in Table 3.

[0085] [Table 3]

[0086]

[0087] In the subsequent step S22, the eNB transmits "allowedBC-ListMRDC" to the gNB.

[0088] In step S23, the gNB selects the EN-DC band combination from "allowedBC-ListMRDC" from the NR unit viewpoint. In the case where the capability of the NR unit is constant in a plurality of EN-DC band combinations, the EN-DC band combination in the order of the head in the list is selected.

[0089] In the above examples of 1) - 3), in step S23, 1) notified by "allowedBC-ListMRDC" is not selected because the NR side is not 100 MHz bandwidth. 2) and 3) notified by "allowedBC-ListMRDC" are selected by the gNB because the capability of the NR side is the same under 100 MHz bandwidth.

[0090] Further, for the EN-DC band combination "allowedBC-ListMRDC" notified to the gNB as a solution candidate, as a priority that can be further notified from the LTE unit viewpoint (for example, notified by a new information element), the following operation can also be specified in the eNB and the gNB.

[0091] The eNB does not perform range narrowing other than the LTE side PCell viewpoint in "allowedBC-ListMRDC" notified to the gNB, and explicitly notifies the gNB of the priority of each EN-DC band combination from the LTE unit viewpoint.

[0092] The gNB selects the EN-DC band combination from the list of "allowedBC-ListMRDC" from the NR unit viewpoint. In the case where the capabilities of the NR units are the same, the EN-DC band combination with a high priority is selected based on the priority notified from the eNB.

[0093] Figure 7 is a flowchart for explaining example (2) of band combination selection in the embodiment of the present application. In step S31, the eNB does not perform range narrowing other than the LTE side PCell viewpoint in the information element "allowedBC-ListMRDC" notified to the gNB, and further includes information explicitly indicating the priority of each EN-DC band combination in the list of EN-DC band combinations from the LTE unit viewpoint.

[0094] As an example, the terminal 20 supports the EN-DC band combinations of 1) - 3) shown below, the area quality condition of LTE is LTE 1.7 GHz superior to LTE 1.5 GHz, and the NR side is applied with a 100 MHz bandwidth.

[0095] 1) LTE 5CC + NR (40 MHz bandwidth)

[0096] 2) LTE 2 GHz (20 MHz bandwidth) + LTE 1.5 GHz (15 MHz bandwidth) + NR 3.7 GHz (100 MHz bandwidth)

[0097] 3) LTE 2 GHz (20 MHz bandwidth) + LTE 1.7 GHz (20 MHz bandwidth) + NR 3.7 GHz (100 MHz bandwidth)

[0098] In step S31, as shown in Table 4, a list of EN-DC band combinations including information indicating priority 1 for 1), priority 3 for 2), and priority 2 for 3) is set in "allowedBC-ListMRDC" according to the performance from the LTE viewpoint. Here, the value indicating the priority is defined such that the lower the value, the higher the priority.

[0099] [Table 4]

[0100]

[0101] In addition, the value indicating the priority can be defined as the lower the value, the higher the priority, or the higher the value, the higher the priority. Furthermore, the information element indicating the priority can be attached to each of the entries of the EN-DC band combination of the list, or can be an information element notified separately from the entries of the EN-DC band combination of the list.

[0102] In a subsequent step S32, the eNB transmits the "allowedBC-ListMRDC" to the gNB.

[0103] In step S33, the gNB selects the EN-DC band combination from the "allowedBC-ListMRDC" from the NR unit viewpoint. In a case where the capability of the NR unit is constant among the plurality of EN-DC band combinations, the EN-DC band combination with the higher priority is selected.

[0104] In the above-described examples of 1) to 3), in step S33, 1) notified by the "allowedBC-ListMRDC" is not selected because the NR side is not 100 MHz bandwidth. 2) and 3) notified by the "allowedBC-ListMRDC" are selected because the capability of the NR side is the same under 100 MHz bandwidth, and 3) indicating the lower value of the priority, that is, the higher priority, is selected.

[0105] According to the above-described embodiment, the terminal 20 can select the optimal EN-DC band combination from the viewpoint of the throughput that comprehensively considers the performance of the LTE unit and the NR unit, and improvement of the user experience is expected.

[0106] That is, in the wireless communication system, the performance at the time of dual connectivity can be improved.

[0107] (Apparatus Structure)

[0108] Next, a functional structure example of the base station 10 and the terminal 20 that execute the processes and operations explained so far will be described. The base station 10 and the terminal 20 include the functions to implement the above-described embodiment. However, the base station 10 and the terminal 20 can each have only a part of the functions in the embodiment.

[0109] < Base Station 10 >

[0110] Figure 8 is a diagram showing an example of the functional structure of the base station 10 in the embodiment of the present application. As shown in FIG. 27, the base station 10 includes a communication unit 1001, a storage unit 1002, and a control unit 1003. Figure 8As shown, the base station 10 has a transmission unit 110, a reception unit 120, a setting unit 130, a control unit 140. Figure 8 The functional structure shown is only an example. As long as the operations involved in the embodiments of the present application can be performed, the functional divisions and the names of the functional units can be arbitrary.

[0111] The transmission unit 110 includes a function of generating a signal to be transmitted to the terminal 20 side and transmitting the signal through wireless. Further, the transmission unit 110 transmits an inter-network node message to other network nodes. The reception unit 120 includes a function of receiving various signals transmitted from the terminal 20 and taking, for example, higher layer information from the received signals. Further, the transmission unit 110 has a function of transmitting an NR-PSS, an NR-SSS, an NR-PBCH, a DL / UL control signal, and the like to the terminal 20. Further, the reception unit 120 receives an inter-network node message from other network nodes.

[0112] The setting unit 130 stores setting information set in advance and various setting information transmitted to the terminal 20. The content of the setting information is, for example, information involved in transmission / reception setting corresponding to the UE capability of the terminal 20 and the like.

[0113] The control unit 140 performs control involved in the processing of the UE capability report related to the wireless parameter received from the terminal 20 as explained in the embodiments. Further, the control unit 140 controls the communication with the terminal 20 based on the UE capability report related to the wireless parameter received from the terminal 20. A functional unit related to the signal transmission in the control unit 140 can also be included in the transmission unit 110, and a functional unit related to the signal reception in the control unit 140 can also be included in the reception unit 120.

[0114] <Terminal 20>

[0115] Figure 9 is a diagram showing an example of the functional structure of the terminal 20 in the embodiments of the present application. As shown, the terminal 20 has a transmission unit 210, a reception unit 220, a setting unit 230, a control unit 240. Figure 9 Figure 9 The functional structure shown is only an example. As long as the operations involved in the embodiments of the present application can be performed, the functional divisions and the names of the functional units can be arbitrary.

[0116] ​The transmission unit 210 creates a transmission signal in accordance with transmission data and transmits the transmission signal wirelessly. The reception unit 220 receives various signals wirelessly and acquires higher layer signals from the received physical layer signals. Further, the reception unit 220 has a function of receiving an NR-PSS, an NR-SSS, an NR-PBCH, a DL / UL / SL control signal, and the like, which are transmitted from the base station 10. Further, for example, the transmission unit 210 transmits a PSCCH (Physical Sidelink Control Channel), a PSSCH (Physical Sidelink Shared Channel), a PSDCH (Physical Sidelink Discovery Channel), a PSBCH (Physical Sidelink Broadcast Channel), and the like as D2D communication to other terminals 20, and the reception unit 120 receives a PSCCH, a PSSCH, a PSDCH, or a PSBCH, and the like from other terminals 20.

[0117] The setting unit 230 stores various setting information received by the reception unit 220 from the base station 10. Further, the setting unit 230 also stores setting information set in advance. The content of the setting information is, for example, information related to transmission / reception settings corresponding to UE capabilities and the like.

[0118] The control unit 240 performs control related to UE capability reporting of a wireless parameter of the terminal 20 as explained in the embodiments. A functional unit related to signal transmission in the control unit 240 can also be included in the transmission unit 210, and a functional unit related to signal reception in the control unit 240 can also be included in the reception unit 220.

[0119] (Hardware structure)

[0120] The block diagrams used in the explanation of the above-described embodiments Figure 8 and Figure 9 illustrate blocks of functional units. These functional blocks (structural units) are realized by any combination of at least one of hardware and software. Further, the method of realizing each functional block is not particularly limited. That is, each functional block can be realized by one device which is physically or logically integrated, or can be realized by a plurality of devices which are physically or logically separated and connected directly or indirectly (for example, by wire, wireless, or the like). Each functional block can also be realized by combining the above-described one device or the above-described plurality of devices with software.

[0121] In the functions, there are judgment, decision, determination, calculation, computation, processing, derivation, investigation, search, confirmation, reception, transmission, output, access, solution, selection, election, establishment, comparison, assumption, expectation, consideration, broadcasting, notifying, communicating, forwarding, configuring, reconfiguring, allocating, mapping, assigning, and the like, but are not limited to these. For example, a functional block (structural unit) that implements a transmission function is called a transmitting unit, a transmitter. Any one of these is as described above, and the implementation method is not particularly limited.

[0122] For example, the base station 10, the terminal 20, and the like in an embodiment of the present disclosure can also function as a computer that performs processing of the wireless communication method of the present disclosure. Figure 10 is a diagram illustrating an example of a hardware structure of the base station 10 and the terminal 20 according to an embodiment of the present disclosure. The base station 10 and the terminal 20 described above can also be physically configured as a computer device including a processor 1001, a storage 1002, an auxiliary storage 1003, a communication device 1004, an input device 1005, an output device 1006, a bus 1007, and the like.

[0123] In addition, in the following description, the term "device" can be replaced with circuit, equipment, unit, and the like. The hardware structure of the base station 10 and the terminal 20 can be configured to include one or more of each device illustrated in the diagram, or can be configured not to include a part of the devices.

[0124] As for each function in the base station 10 and the terminal 20, for example, at least one of the operation by the processor 1001 based on the communication by the communication device 1004, or the readout and the write of data in the storage 1002 and the auxiliary storage 1003 is implemented by reading specific software (program) into the hardware such as the processor 1001 and the storage 1002, and performing operation by the processor 1001, and controlling the communication based on the communication device 1004, or the readout and the write of data in the storage 1002 and the auxiliary storage 1003.

[0125] The processor 1001 causes, for example, an operating system to operate to control the entire computer. The processor 1001 can also be configured by a central processing device (central processing unit (CPU)) including an interface with a peripheral device, a control device, an arithmetic device, a register, and the like. For example, the control unit 140, the control unit 240, and the like described above can also be implemented by the processor 1001.

[0126] Further, the processor 1001 reads out programs (program codes), software modules, or data, etc. from at least one of the auxiliary storage apparatus 1003 and the communication apparatus 1004 to the storage apparatus 1002, and executes various processes according to them. As the programs, programs that cause the computer to execute at least a part of the operations explained in the above-described embodiments can be used. For example, Figure 8 The control unit 140 of the base station 10 illustrated can also be realized by a control program stored in the storage apparatus 1002 and operated in the processor 1001. Further, for example, Figure 9 The control unit 240 of the terminal 20 illustrated can also be realized by a control program stored in the storage apparatus 1002 and operated in the processor 1001. The above-described various processes performed by one processor 1001 are explained, but can also be performed by two or more processors 1001 simultaneously or sequentially. The processor 1001 can also be realized by one or more chips. In addition, the programs can also be transmitted from a network via an electric communication line.

[0127] The storage apparatus 1002 can also be a computer-readable recording medium, such as at least one of a ROM (Read Only Memory), an EPROM (Erasable Programmable ROM), an EEPROM (Electrically Erasable Programmable ROM), a RAM (Random Access Memory), and the like. The storage apparatus 1002 can also be referred to as a register, a cache, a main memory (main storage apparatus), and the like. The storage apparatus 1002 is capable of holding programs (program codes), software modules, and the like that are executable for implementing the communication method related to one embodiment of the present disclosure.

[0128] The auxiliary storage apparatus 1003 can also be a computer-readable recording medium, such as at least one of a CD-ROM (Compact Disc ROM), an optical disk, a hard disk drive, a flexible disc, a magneto-optical disk (for example, a compact disc, a digital versatile disc, a Blu-ray (registered trademark) disc), a smart card, a flash memory (for example, a card, a stick, a key drive), a soft (Floppy (registered trademark)) disc, a magnetic stripe, and the like. The above-described storage medium can also be, for example, a database, a server, or another appropriate medium that includes at least one of the storage apparatus 1002 and the auxiliary storage apparatus 1003.

[0129] The communication device 1004 is hardware (transmission-reception device) for performing communication between computers via at least one of a wired network and a wireless network, for example, also referred to as a network device, a network controller, a network card, a communication module, and the like. The communication device 1004 can also be configured to include a high-frequency switch, a duplexer, a filter, a frequency synthesizer, and the like in order to realize at least one of, for example, frequency division duplex (FDD) and time division duplex (TDD). For example, a transmission-reception antenna, an amplifier unit, a transmission-reception unit, a transmission path interface, and the like can also be implemented by the communication device 1004. The transmission-reception unit can also be implemented physically or logically separated by a transmission unit and a reception unit.

[0130] The input device 1005 is an input device (for example, a keyboard, a mouse, a microphone, a switch, a button, a sensor, and the like) that receives an input from the outside. The output device 1006 is an output device (for example, a display, a speaker, an LED lamp, and the like) that performs output to the outside. In addition, the input device 1005 and the output device 1006 can also be a structure that is integrated (for example, a touch panel).

[0131] Furthermore, the processor 1001 and each of the storage device 1002 and the like are connected through a bus 1007 for communication of information. The bus 1007 can be configured with a single bus, or can be configured with different buses between the devices.

[0132] Furthermore, the base station 10 and the terminal 20 can also be configured to include a microprocessor, a digital signal processor (DSP), an ASIC (Application Specific Integrated Circuit), a PLD (Programmable Logic Device), an FPGA (Field Programmable Gate Array), and the like, and a part or all of each functional block can also be implemented using the hardware. For example, the processor 1001 can also be implemented using at least one of these hardware.

[0133] (Summary of Embodiments)

[0134] According to the above-described structure, the terminal 20 can select the optimal EN-DC band combination from the viewpoint of throughput that comprehensively considers the performance of the LTE unit and the NR unit, and improvement of user experience is expected. That is, in the wireless communication system, the performance at the time of dual connectivity can be improved.

[0135] According to the above-described structure, the terminal 20 can select the optimal EN-DC band combination from the viewpoint of throughput that comprehensively considers the performance of the LTE unit and the NR unit, and improvement of user experience is expected. That is, in the wireless communication system, the performance at the time of dual connectivity can be improved.

[0136] The control unit can also set the band combinations included in the candidate list in order of performance in the first RAT. According to this structure, the terminal 20 can select the optimal EN-DC band combination from the viewpoint of throughput that comprehensively considers the performance of the LTE unit and the NR unit.

[0137] The control unit can also attach a priority to each of the band combinations included in the candidate list. According to this structure, the terminal 20 can select the optimal EN-DC band combination from the viewpoint of throughput that comprehensively considers the performance of the LTE unit and the NR unit.

[0138] Further, according to an embodiment of the present application, there is provided a base station having: a reception unit that receives, from a base station of the first RAT, a candidate list of band combinations used in dual connectivity of the first RAT and a second RAT that is decided based on a capability related to the first RAT; a control unit that selects, from the candidate list, an appropriate band combination used in the dual connectivity based on a capability related to the second RAT; and a transmission unit that transmits, to a base station in the first RAT, information indicating the selected band combination.

[0139] According to the above structure, the terminal 20 is able to select the optimum EN-DC band combination from the viewpoint of throughput that comprehensively considers the performance of the LTE unit and the NR unit, and improvement of user experience is expected. That is, in the wireless communication system, the performance at the time of dual connectivity can be improved.

[0140] Further, according to an embodiment of the present application, there is provided a terminal having: a reception unit that receives, in a first RAT (Radio access technology), a message that requests reporting of terminal capability from a base station; a control unit that, based on the message that requests reporting of the terminal capability, includes, in a message that reports terminal capability, capability related to the first RAT, capability related to a second RAT, and capability related to dual connectivity using the first RAT and the second RAT; and a transmission unit that transmits, in the first RAT, the message that reports the terminal capability to the base station, the reception unit and the transmission unit performing dual connectivity-based communication using a band combination that is respectively appropriate for the first RAT and the second RAT.

[0141] Further, according to an embodiment of the present application, there is provided a terminal having: a reception unit that receives, in a first RAT (Radio access technology), a message that requests reporting of terminal capability from a base station; a control unit that, based on the message that requests reporting of the terminal capability, includes, in a message that reports terminal capability, capability related to the first RAT, capability related to a second RAT, and capability related to dual connectivity using the first RAT and the second RAT; and a transmission unit that transmits, in the first RAT, the message that reports the terminal capability to the base station, the reception unit and the transmission unit performing dual connectivity-based communication using a band combination that is respectively appropriate for the first RAT and the second RAT.

[0142] Further, according to an embodiment of the present application, there is provided a communication method in which a base station performs: a transmission step of transmitting, in a first RAT (Radio access technology), a message that requests reporting of terminal capability to a terminal; a reception step of receiving, in the first RAT, a message that reports terminal capability from the terminal, the terminal capability including capability related to the first RAT, capability related to a second RAT, and capability related to dual connectivity using the first RAT and the second RAT; and a control step of deciding a candidate list of band combinations used in the dual connectivity based on the capability related to the first RAT, the transmission step including a step of transmitting the candidate list to a base station in the second RAT, the reception step including a step of receiving, from the base station in the second RAT, information indicating an appropriate band combination selected from the candidate list by the base station in the second RAT based on the capability related to the second RAT.

[0143] Further, according to an embodiment of the present application, there is provided a terminal having: a reception unit that receives, in a first RAT (Radio access technology), a message that requests reporting of terminal capability from a base station; a control unit that, based on the message that requests reporting of the terminal capability, includes, in a message that reports terminal capability, capability related to the first RAT, capability related to a second RAT, and capability related to dual connectivity using the first RAT and the second RAT; and a transmission unit that transmits, in the first RAT, the message that reports the terminal capability to the base station, the reception unit and the transmission unit performing dual connectivity-based communication using a band combination that is respectively appropriate for the first RAT and the second RAT.

[0144] (Supplement to Embodiments)

[0145] The above describes embodiments of the present application, but the disclosed application is not limited to such embodiments, and those skilled in the art will understand various modifications, corrections, alternatives, substitutions, and the like. Specific numerical examples are used to facilitate understanding of the application, but as long as there is no specific description, these numerical examples are only examples, and any appropriate value can be used. The division of items in the above description is not essential in the present application, and items described in two or more items can be used in combination as needed, or items described in other items can be applied (as long as there is no contradiction) to items described in a certain item. The boundary of a functional unit or a processing unit in a functional block diagram does not necessarily correspond to the boundary of a physical component. The operation of multiple functional units can be physically performed by one component, or the operation of one functional unit can be physically performed by multiple components. The order of the processes described in the embodiments can be changed as long as there is no contradiction. The base station 10 and the terminal 20 are described using a functional block diagram for convenience of explanation of the processes, but such devices can be implemented by hardware, software, or a combination thereof. Software operated by the processor included in the base station 10 according to the embodiments of the present application and software operated by the processor included in the terminal 20 according to the embodiments of the present application can be respectively stored in a random access memory (RAM), a flash memory, a read only memory (ROM), an EPROM, an EEPROM, a register, a hard disk (HDD), a removable disk, a CD-ROM, a database, a server, and any other appropriate storage medium.

[0146] In addition, the notification of information is not limited to the manner / implementation method described in the present disclosure, and may also be performed by other methods. For example, the notification of information may also be implemented through physical layer signaling (e.g., DCI (Downlink Control Information), UCI (Uplink Control Information)), high-layer signaling (e.g., RRC (Radio Resource Control) signaling, MAC (Medium Access Control) signaling, broadcast information (MIB (Master Information Block), SIB (System Information Block)), other signals or a combination thereof. In addition, RRC signaling may also be referred to as an RRC message, for example, an RRC Connection Setup message, an RRC Connection Reconfiguration message, etc.

[0147] The various methods and implementations described in the present disclosure may also be applied to at least one of LTE (Long Term Evolution), LTE-A (LTE-Advanced), SUPER 3G, IMT-Advanced, 4G (fourth generation mobile communication system), 5G (fifth 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), systems utilizing other appropriate systems, and next-generation systems expanded upon these. In addition, multiple systems can also be combined for application (for example, a combination of at least one of LTE and LTE-A with 5G, etc.).

[0148] The processing procedures, sequences, flow charts, etc. of each method / implementation described in this specification may be reversed as long as there is no contradiction. For example, the methods described in this disclosure use an illustrative order to present various step elements, but are not limited to the specific order presented.

[0149] In this specification, specific operations are performed by base station 10, and sometimes, depending on the situation, by its upper node. Obviously, in a network including one or more network nodes including base station 10, various operations performed for communication with terminal 20 may be performed by at least one of base station 10 and other network nodes other than base station 10 (e.g., MME or S-GW, but not limited thereto). While the above example illustrates a single other network node other than base station 10, the other network node may also be a combination of multiple other network nodes (e.g., MME and S-GW).

[0150] The information or signals described in this disclosure may be output from a higher layer (or a lower layer) to a lower layer (or a higher layer), or may be input or output via a plurality of network nodes.

[0151] Input and output information can be stored in a specific location (e.g., memory) or managed using a management table. Input and output information can be overwritten, updated, or appended. Output information can also be deleted. Input information can also be sent to other devices.

[0152] The determination in the present disclosure can be made by a value represented by a bit (0 or 1), a true or false value (Boolean value: true or false), or by comparison of numerical values ​​(for example, comparison with a specific value).

[0153] Software, regardless of the terminology used, that can be referred to as software, firmware, middleware, microcode, hardware-description language, or by other designation, should be interpreted broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software modules, applications, software applications, software packages, routines, subroutines, objects, executables, threads of execution, procedures, functions, etc.

[0154] Further, software, instructions, information, and so on can also be transmitted or received via a transmission medium. For example, in cases where software is transmitted from a website, server, or other remote source using at least one of wired technology (coaxial cables, fiber optic cables, twisted pair cables, digital subscriber line (DSL), or others) and / or wireless technology (infrared, microwave, radio frequency, etc.), at least one of these technologies is included within the definition of transmission medium.

[0155] The information, signals, and so on that can be described in this disclosure can be represented using various technologies and / or techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that can be referenced throughout the above description can be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

[0156] In addition, terms used in this disclosure and terms needed for understanding this disclosure can be replaced with terms having the same or similar meanings. For example, at least one of a channel and a symbol can also be a signal (signaling). Also, a signal can be a message. Also, a component carrier (CC) can be referred to as a carrier frequency, a cell, a frequency carrier, or the like.

[0157] The terms "system" and "network" used in this disclosure are used interchangeably.

[0158] Moreover, information, parameters, and the like explained in the present disclosure can be expressed by absolute values, can be expressed by relative values with respect to specific values, and can be expressed by corresponding other information. For example, a radio resource can also be indicated by an index.

[0159] The names used for the above-described parameters are not limiting names in all respects. Furthermore, mathematical expressions and the like using these parameters can also be different from those explicitly disclosed in the present disclosure. Various channels (e.g., PUCCH, PDCCH, and the like) and information elements can be identified by any appropriate names, and thus various names assigned to these various channels and information elements are not limiting names in all respects.

[0160] In the present disclosure, the terms "base station (BS)", "wireless base station", "base station device", "fixed station", "NodeB", "eNodeB (eNB)", "gNodeB (gNB)", "access point", "transmission point", "reception point", "transmission / reception point", "cell", "sector", "cell group", "carrier", "component carrier", and the like can be used interchangeably. There are also cases where the base station is referred to by the terms "macro cell", "small cell", "femto cell", "pico cell", and the like.

[0161] A base station can accommodate one or a plurality of (e.g., three) cells. In the case where the base station accommodates a plurality of cells, the coverage area of the base station as a whole can be divided into a plurality of smaller areas, and each smaller area can also be provided with a communication service by a base station subsystem (e.g., a small-sized base station for indoor use (Remote Radio Head (RRH))). The term "cell" or "sector" refers to a part or the whole of the coverage area of at least one of the base station and the base station subsystem that provides a communication service in that coverage.

[0162] In the present disclosure, the terms "mobile station (MS)", "user terminal", "user device (UE)", "terminal", and the like can be used interchangeably.

[0163] There are also instances where those skilled in the art refer to the mobile station 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, hand set, user agent, mobile client, client, or by some other suitable terminology.

[0164] At least one of the base station and the mobile station can also be referred to as a transmission device, a reception device, a communication device, or the like. In addition, at least one of the base station and the mobile station can also be a device mounted on a mobile body, a mobile body itself, or the like. The mobile body can be a vehicle (for example, a car, an airplane, or the like), a mobile body that moves in an unmanned manner (for example, a drone, an automated driving vehicle, or the like), or a robot (manned or unmanned). In addition, at least one of the base station and the mobile station also includes a device that does not necessarily move when performing a communication operation. For example, at least one of the base station and the mobile station can also be an IoT (Internet of Things) device such as a sensor.

[0165] Furthermore, the base station in the present disclosure can also be replaced with a user terminal. For example, for a structure in which communication between the base station and the user terminal is replaced with communication between a plurality of terminals 20 (for example, can also be referred to as D2D (Device-to-Device), V2X (Vehicle-to-Everything), or the like), each of the modes / embodiments of the present disclosure can also be applied. In this case, the structure can also be provided in which the terminal 20 has the functions of the base station 10 described above. Furthermore, the terms such as "uplink" and "downlink" can also be replaced with terms corresponding to the inter-terminal communication (for example, "side"). For example, the uplink channel, the downlink channel, or the like can also be replaced with a side channel.

[0166] Likewise, the user terminal in the present disclosure can also be replaced with a base station. In this case, the structure can also be provided in which the base station has the functions of the user terminal described above.

[0167] The terms "determining," "deciding," and the like, as used in the disclosure, encompass a wide variety of actions. For example, "determining" or "deciding" can include judging, calculating, computing, processing, deriving, investigating, searching (e.g., looking up in a table, a database, or another data structure), ascertaining, and the like, as can be deemed appropriate. Also, "determining" or "deciding" can include receiving (e.g., receiving information), transmitting (e.g., transmitting information), inputting, outputting, accessing (e.g., accessing data in a memory), and the like, as can be deemed appropriate. Also, "determining" or "deciding" can include resolving, selecting, choosing, establishing, comparing, and the like, as can be deemed appropriate. That is, "determining" or "deciding" can include any operation as can be deemed appropriate. Also, "determining" or "deciding" can be replaced by "assuming," "expecting," "considering," and the like.

[0168] The terms "connected," "coupled," and the like, as used in the disclosure, mean all possible operational and positional relationships between the elements. The term "connected" can also mean elements that are "connected," "coupled," or "accessed" to each other by the existence of one or more intermediate elements. The coupling or connection between the elements can be physical or logical, or a combination thereof. For example, "connected" can be replaced with "accessed." In the case of use in the disclosure, two elements can be "connected" or "coupled" to each other using at least one of one or more wires, cables and printed circuits, and as several non-limiting and non-inclusive examples, electromagnetic energy having wavelengths in the radio frequency region, the microwave region, and the light (both visible and invisible) region.

[0169] The reference signal can also be simply referred to as RS (Reference Signal), and can also be referred to as a pilot (Pilot) depending on the applied standard.

[0170] The description "based on" used in the present disclosure does not mean "only based on" unless specifically written. In other words, the description "based on" means both "only based on" and "at least based on".

[0171] Any reference to elements using the terms "first", "second", and the like used in the present disclosure does not comprehensively limit the number or order of the elements. The terms can be used in the present disclosure as a convenient method of distinguishing between two or more elements. Therefore, a reference to a first and second element does not mean that only two elements can be employed, or that the first element must be employed prior to the second element.

[0172] The "unit", "circuit", "device", and the like can also be substituted for "component" in the configuration of each of the above-described apparatuses.

[0173] In the present disclosure, the terms "include", "including", and the like are used in the same meaning as the term "comprising", and are inclusive. Further, the term "or" used in the present disclosure does not mean exclusive or.

[0174] A radio frame can also be composed of one or more frames in the time domain. Each of the one or more frames can also be referred to as a subframe. Further, a subframe can also be composed of one or more slots in the time domain. The subframe can also be a fixed length of time (e.g., 1 ms) independent of numerology.

[0175] The numerology can also be a communication parameter applied in at least one of transmission and reception of a certain signal or channel. The numerology can also indicate at least one of, for example, 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 specific filtering processing performed by a transmitter-receiver in the frequency domain, a specific windowing processing performed by the transmitter-receiver in the time domain, and the like.

[0176] A slot can also be composed of one or a plurality of symbols (OFDM (Orthogonal Frequency Division Multiplexing) symbols, SC-FDMA (Single Carrier Frequency Division Multiple Access) symbols, and the like) in the time domain. A slot can also be a time unit based on a numerology.

[0177] A slot can also include a plurality of mini-slots. Each mini-slot can also be composed of one or a plurality of symbols in the time domain. Further, a mini-slot can also be referred to as a sub-slot. A mini-slot can also be composed of a smaller number of symbols than a slot. A PDSCH (or PUSCH) transmitted in a larger time unit than a mini-slot can also be referred to as PDSCH (or PUSCH) mapping type A. A PDSCH (or PUSCH) transmitted using a mini-slot can also be referred to as PDSCH (or PUSCH) mapping type B.

[0178] A radio frame, a subframe, a slot, a mini-slot, and a symbol each represent a time unit for transmitting a signal. A radio frame, a subframe, a slot, a mini-slot, and a symbol can also be referred to by other names.

[0179] For example, one subframe can also be referred to as a transmission time interval (TTI), a plurality of consecutive subframes can also be referred to as a TTI, one slot or one mini-slot can also be referred to as a TTI. That is, at least one of a subframe and a TTI can be a subframe (1 ms) in the existing LTE, can be a period shorter than 1 ms (for example, 1-13 symbols), or can be a period longer than 1 ms. In addition, a unit representing a TTI can not be referred to as a subframe, but can be referred to as a slot, a mini-slot, or the like.

[0180] Here, a TTI, for example, refers to a minimum time unit of scheduling in wireless communication. For example, in an LTE system, a base station performs scheduling in which a radio resource (a frequency bandwidth, a transmission power, and the like that can be used in each terminal 20) is allocated to each terminal 20 in a TTI unit. In addition, the definition of a TTI is not limited thereto.

[0181] A TTI can also be a transmission time unit of a data packet (a transport block), a code block, a codeword, or the like that has been channel-encoded, and can also become a processing unit of scheduling, link adaptation, or the like. In addition, when a TTI is given, a time interval (for example, a number of symbols) to which a transport block, a code block, a codeword, or the like is actually mapped can be shorter than the TTI.

[0182] In addition, in a case where one slot or one mini-slot is referred to as a TTI, one or more TTIs (i.e., one or more slots or one or more mini-slots) can also be a minimum time unit of scheduling. Furthermore, the number of slots (mini-slots) constituting the minimum time unit of scheduling can also be controlled.

[0183] A TTI having a time length of 1 ms can also be referred to as 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 the normal TTI can also be referred to as a shortened TTI, a short TTI, a partial or fractional TTI, a shortened subframe, a short subframe, a mini-slot, a sub-slot, a slot, etc.

[0184] In addition, the long TTI (e.g., normal TTI, subframe, etc.) can also be replaced with a TTI having a time length of more than 1 ms, and the short TTI (e.g., shortened TTI, etc.) can also be replaced with a TTI having a TTI length shorter than the long TTI and a TTI length of 1 ms or more.

[0185] A resource block (RB) is a resource allocation unit in the time domain and the frequency domain, and can also include one or more contiguous subcarriers (subcarriers) in the frequency domain. The number of subcarriers included in the RB can also be the same regardless of the numerology, for example, can also be 12. The number of subcarriers included in the RB can also be determined based on the numerology.

[0186] In addition, the time domain of the RB can also include one or more symbols, and can also be the length of one slot, one mini-slot, one subframe, or one TTI. One TTI, one subframe, etc. can also be constituted by one or more resource blocks, respectively.

[0187] In addition, one or more RBs can also be referred to as a physical resource block (PRB), a subcarrier group (SCG), a resource element group (REG), a PRB pair, an RB pair, etc.

[0188] In addition, a resource block can also be constituted by one or more resource elements (REs). For example, one RE can also be a wireless resource area of one subcarrier and one symbol.

[0189] A bandwidth part (BWP: Bandwidth Part) (may also be referred to as a partial bandwidth, etc.) can also indicate a subset of contiguous common RBs (common resource blocks) for a certain numerology in a certain carrier. Here, the common RBs can also be determined by the indices of the RBs with reference to a common reference point of the carrier. The PRBs can also be defined in a certain BWP and additionally numbered within the BWP.

[0190] A BWP for UL (UL BWP) and a BWP for DL (DL BWP) can also be included in the BWP. For a UE, one or a plurality of BWPs can also be configured within one carrier.

[0191] At least one of the configured BWPs can also be activated, and the UE can not be assumed to transmit and receive a specific signal / channel outside the activated BWP. In addition, "cell", "carrier", etc. in the present disclosure can also be replaced with "BWP".

[0192] The above-described structures of radio frames, subframes, slots, mini-slots, and symbols, etc. are merely examples. For example, the number of subframes included in a radio frame, the number of slots of each subframe or radio frame, the number of mini-slots included in a slot, the number of symbols included in a slot or a mini-slot, the number of RBs, the number of subcarriers included in an RB, and the number of symbols, symbol length, cyclic prefix (CP) length, etc. within a TTI can be variously changed.

[0193] In the present disclosure, for example, in the case where an article is added by a definite article such as "a", "an", and "the" in English, the present disclosure can also include a case where the article added after the definite article is plural.

[0194] In the present disclosure, the term "A is different from B" can also mean "A and B are different from each other". In addition, the term can also mean "A and B are different from C, respectively". The terms "separate", "combine", etc. can also be interpreted in the same manner as "different".

[0195] Each of the modes / embodiments described in the present disclosure can be used alone or in combination, and can also be used in switching as execution proceeds. Furthermore, notification of specific information (for example, notification of "X") is not limited to being explicitly performed, and can also be performed implicitly (for example, without notification of the specific information).

[0196] In addition, in the present disclosure, "UECapabilityEnquiry" is an example of a message that requests a report of terminal capability. "UECapabilityInformation" is an example of a message that reports terminal capability. UE-MRDC-Capability is an example of capability involved in dual connectivity. UE-EUTRA-Capability is an example of capability involved in the first RAT. UE-NR-Capability is an example of capability involved in the second RAT. allowedBC-ListMRDC is an example of a candidate list of frequency band combinations used in dual connectivity. selectedBandCombination is an example of information indicating a proper frequency band combination selected by a base station in the second RAT.

[0197] The above has been described in detail with respect to the present disclosure, but it is obvious 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 as modifications and changes without departing from the spirit and scope of the present disclosure determined based on the recitations of the claims. Therefore, the recitations of the present disclosure are intended for the purpose of illustrative explanation, and do not have any limiting meaning on the present disclosure.

[0198] Explanation of Reference Signs

[0199] 10 base station

[0200] 110 transmission unit

[0201] 120 reception unit

[0202] 130 setting unit

[0203] 140 control unit

[0204] 20 terminal

[0205] 210 transmission unit

[0206] 220 reception unit

[0207] 230 setting unit

[0208] 240 control unit

[0209] 1001 processor

[0210] 1002 storage device

[0211] 1003 auxiliary storage device

[0212] 1004 communication device

[0213] 1005 input device

[0214] 1006 output device

Claims

1. A base station, comprising: a first base station configured to establish a dual connection with a second base station; and a control unit, configured to determine a candidate list of frequency band combinations used in the dual connectivity based on capabilities of the first base station; a sending unit, configured to send the candidate list to a second base station; as well as a receiving unit configured to receive, from the second base station, information indicating an appropriate frequency band combination selected by the second base station from the candidate list; The control unit arranges the frequency band combinations included in the candidate list in an order determined from a viewpoint of the first base station.

2. The base station according to claim 1, wherein The sending unit sends a message requesting a report of the terminal capability to the terminal in the RAT (Radio Access Technology) of the first base station, The receiving unit receives a message reporting terminal capabilities from the terminal in the RAT of the first base station, where the terminal capabilities include capabilities related to the first base station.

3. The base station according to claim 1, wherein The sending unit sends a message requesting a report of the terminal capability to the terminal in the RAT (Radio Access Technology) of the first base station, The receiving unit receives a message reporting terminal capabilities from the terminal in the RAT of the first base station, where the terminal capabilities include capabilities related to the first base station, capabilities related to the second base station, and capabilities related to dual connectivity using the first base station and the second base station.

4. The base station according to claim 1, wherein The information is selected from the candidate list based on capabilities involved with the second base station.

5. A terminal comprising: a receiving unit, receiving a message requesting a report of terminal capabilities from the first base station; a control unit, based on the message requesting the report of the terminal capabilities, including the capabilities related to the first base station, the capabilities related to the second base station, and the capabilities related to dual connectivity using the first base station and the second base station in the message reporting the terminal capabilities; as well as a sending unit, configured to send a message reporting the terminal capability to the first base station, The receiving unit and the transmitting unit perform communication based on dual connectivity using an appropriate frequency band combination selected by the second base station from a candidate list including an order determined from the perspective of the first base station.

6. A base station, being a second base station that performs dual connection with a first base station, the base station comprising: a receiving unit configured to receive, from the first base station, a candidate list of frequency band combinations used in a dual connectivity based on capabilities involved in the first base station; a control unit, configured to select a candidate for a frequency band combination used in dual connectivity from the candidate list based on capabilities of the second base station; as well as a sending unit, configured to send information indicating the candidate of the selected frequency band combination to the first base station, The frequency band combinations included in the candidate list are set in an order determined from the perspective of the first base station.

7. A communication method, wherein a base station performs: The step of determining a candidate list of frequency band combinations to be used in the dual connectivity based on the capabilities involved in the first base station; The step of sending the candidate list to a second base station; as well as receiving, from the second base station, information indicating an appropriate frequency band combination selected by the second base station from the candidate list, The frequency band combinations included in the candidate list are arranged in an order determined from the perspective of the first base station.

8. A wireless communication system comprising a first base station and a second base station, The first base station has: a control unit, configured to determine a candidate list of frequency band combinations used in dual connectivity based on capabilities of the first base station; a sending unit, configured to send the candidate list to the second base station; as well as a receiving unit configured to receive, from the second base station, information indicating an appropriate frequency band combination selected by the second base station from the candidate list; The control unit arranges the frequency band combinations included in the candidate list in an order determined from the perspective of the first base station. The second base station has: a receiving unit, configured to receive the candidate list from the first base station; a control unit, configured to select a candidate for a frequency band combination used in dual connectivity from the candidate list based on capabilities of the second base station; as well as The sending unit sends information indicating the candidate of the selected frequency band combination to the first base station.

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