Base station, terminal, communication method, and communication system

Abstract

This base station comprises: a setting unit that associates, as a set, a first cell constituted by a carrier using a first frequency band and a second cell constituted by a carrier using a second frequency band different from the first frequency band; and a control unit that allocates, to a terminal, the first cell and the second cell as a set.

Description

Base Station, Terminal, Communication Method, and Communication System

[0001] The present disclosure relates to a base station, a terminal, a communication method, and a communication system capable of establishing high-throughput communication earlier.

[0002] The 3rd Generation Partnership Project (3GPP (registered trademark)) has specified the 5th generation mobile communication system (also called 5G, New Radio (NR), or Next Generation (NG)). Furthermore, it is also promoting the specification of the next-generation mobile communication system called Beyond 5G, 5G Evolution, or 6G.

[0003] In 4G and 5G mobile communications, in order to increase throughput, techniques such as carrier aggregation (CA: Carrier Aggregation) or dual connectivity (DC: Dual Connectivity) that bundle multiple bands (or frequencies) are used.

[0004] CA enables wideband transmission by simultaneously using multiple carriers called component carriers (CCs) for communication, and DC enables wideband transmission by simultaneously using cells (or carriers constituting cells) between multiple base stations for communication (Non-Patent Document 1, Non-Patent Document 2).

[0005] In a CA (Cabin Area), the UE (User Engineer) initially connects to the base station using the PCC (Primary CC), and reports the quality measurement results of other CCs to the base station. The base station then sequentially adds subsequent SCCs (Secondary CCs) based on these quality measurement results to increase throughput. Similarly, in a DC (Data Center), the UE initially connects to the PCell (Primary cell) of the master node (MN), and reports the quality measurement results of other cells to the master node MN. The master node MN then decides whether to add a secondary node (SN) based on these quality measurement results, requests the secondary node SN to add the node, obtains permission from the secondary node SN, and sequentially adds the PSCell (Primary Secondary Cell) / SCell (Secondary Cell) of the secondary node SN to increase throughput.

[0006] 3GPP TS 38.300 V18.3.0, 3rd Generation Partnership Project;Technical Specification Group Radio Access Network; NR; NR and NG-RAN Overall Description; Stage 2 (Release 18), 3GPP, September 20243GPP TS 37.340 V18.3.0, 3rd Generation Partnership Project;Technical Specification Group Radio Access Network; Evolved Universal Terrestrial Radio Access (E-UTRA) and NR; Multi-connectivity; Overall Description; Stage 2 (Release 18), 3GPP, September 2024

[0007] In the future, with 6G, there may be a demand for achieving high throughput at an earlier stage. However, with conventional CAs and DCs, quality measurements are performed after connecting PCCs or PCells, and SCCs or SCells are added sequentially. This means that it takes a certain amount of time to reach high throughput, and the system cannot meet the new needs of 6G.

[0008] Therefore, this disclosure is made in view of these circumstances and aims to provide a base station, terminal, communication method, and communication system that can establish high-throughput communication at an earlier stage.

[0009] One aspect of the present disclosure is a base station (100) comprising a setting unit (120) that associates a first cell composed of a carrier in a first frequency band and a second cell composed of a carrier in a second frequency band different from the first frequency band as a set, and a control unit (140) that assigns the first cell and the second cell as a set to a terminal.

[0010] One aspect of the present disclosure is a terminal (200) comprising a receiving unit (210) that receives information from a base station indicating that a first cell consisting of carriers in a first frequency band and a second cell consisting of carriers in a second frequency band different from the first frequency band are associated as a set, and a control unit (240) that receives the first cell and the second cell as a set.

[0011] One aspect of the present disclosure is a communication method for a base station (100), comprising the steps of associating a first cell, which consists of carriers in a first frequency band, and a second cell, which consists of carriers in a second frequency band different from the first frequency band, as a set, and assigning the first cell and the second cell as a set to a terminal.

[0012] One aspect of the present disclosure is a system (10) comprising a base station (100) and a terminal (200), wherein the base station (100) includes a setting unit (120) that associates a first cell composed of a carrier in a first frequency band and a second cell composed of a carrier in a second frequency band different from the first frequency band as a set, and a control unit (140) that assigns the first cell and the second cell as a set to the terminal.

[0013] Figure 1 is an overall schematic diagram of the wireless communication system. Figure 2 is a functional block diagram of the base station. Figure 3 is a functional block diagram of the terminal. Figure 4 is a diagram illustrating the basic concept of a virtual cell / CC. Figure 5 is a diagram illustrating a specific example of virtual cell / CC configuration. Figure 6 is a diagram illustrating the sequence for notifying the UE of virtual cell / CC information. Figure 7 is a diagram illustrating the sequence for measuring the virtual cell / CC by the UE. Figure 8 is a diagram illustrating the sequence for adjusting the virtual cell / CC settings between base stations. Figure 9 is a diagram illustrating an example of the connection configuration between a CU and a DU. Figure 10 is a diagram illustrating the sequence for adjusting the virtual cell / CC settings between a CU and a DU (part 1). Figure 11 is a diagram illustrating the sequence for adjusting the virtual cell / CC settings between a CU and a DU (part 2). Figure 12 is a diagram illustrating the sequence for adjusting the virtual cell / CC settings between DUs. Figure 13 is a diagram illustrating the handover sequence between base stations. Figure 14 is a diagram illustrating the cell switching sequence in LTM. Figure 15 is a diagram illustrating an example of the hardware configuration of a base station and a terminal. Figure 16 is a diagram illustrating an example of the vehicle configuration.

[0014] The embodiments will be described below with reference to the drawings. Note that identical or similar reference numerals are used to denote the same functions and components, and their descriptions will be omitted as appropriate.

[0015] (1) Overall schematic diagram 1 of the wireless communication system is an overall schematic diagram of the wireless communication system 10 according to the embodiment. The wireless communication system 10 is a wireless communication system in accordance with 6G and includes a terminal 200 (hereinafter referred to as UE (User Equipment) 200), a base station 100 (100A, 100B), and a network 20.

[0016] The wireless communication system 10 may be a wireless communication system conforming to a method called Beyond 5G or 5G Evolution, or it may partially include a wireless communication system conforming to a method called Long Term Evolution (LTE) or 4G, or 5G New Radio (NR). Furthermore, the wireless communication system 10 may be configured to include other radio access technologies (RATs) in addition to 6G, such as 4G / LTE and 5G. The specific configuration of the wireless system 10 is not limited to the example shown in Figure 1.

[0017] Network 20 includes multiple base stations 100 (100A, 100B). Base stations 100 are, for example, gNBs, and may also include eNBs, etc. Network 20 is connected to a 6G-compliant core network (6GC, not shown).

[0018] Base station 100 is a 6G-compliant wireless base station and performs 6G-compliant wireless communication with UE200. Base station 100 can support carrier aggregation (CA), which uses multiple component carriers (CCs) bundled together, and dual connectivity (DC), which enables simultaneous communication between base stations, by using Massive Multiple-Input Multiple-Output (Massive MIMO), which generates a more directional beam by controlling the wireless signals transmitted from multiple antenna elements.

[0019] The base station 100 may consist of a CU (Central Unit) and a DU (Distributed Unit), the DU being located separately from the CU at a geographically different location. One or more DUs may be connected to the CU. For example, the base station 100 may employ a fronthaul (FH) interface as defined by the O-RAN (Open Radio Access Network Alliance) and may include an O-DU (O-RAN Distributed Unit) and an O-RU (O-RAN Radio Unit).

[0020] The base stations 100 may be connected by an Xn interface, and the CU and DU may be connected by an F1 interface.

[0021] The base station 100 and UE200 can support CA (Carrier Aggregation) which uses multiple CCs together, and DC (Data Center) which communicates simultaneously between the UE and multiple base stations, by controlling the radio signals transmitted from multiple antenna elements. In particular, in this embodiment, the base station 100 assigns multiple component carrier CCs as a set using a virtual component CC, or multiple cells as a set using a virtual cell, to the UE200, thereby enabling high-throughput CA or DC at an early stage.

[0022] In the wireless communication system 10, in addition to mobility management of the UE200 at Layer 3 (which may include, for example, the Radio Resource Control Layer (RRC)) (which may also be called L3 Mobility), mobility management at Layer 1 / Layer 2 (which may include, for example, the Media Access Control Layer (MAC)) (which may also be called L1 / L2 mobility or LTM) may be applied. L3 Mobility may be interpreted as mobility control at the Radio Resource Control Layer (RRC). On the other hand, L1 / L2 mobility may be interpreted as mobility control at the Physical Layer (PHY), Media Access Control Layer (MAC), Radio Link Control Layer (RLC), and Packet Data Convergence Protocol Layer (PDCP).

[0023] The UE200 is a terminal capable of performing wireless communication in accordance with 6G, and may also perform wireless communication in accordance with communication methods called Beyond 5G or 5G Evolution. It may also have the capability to perform wireless communication in accordance with LTE / 4G or NR / 5G.

[0024] The UE200 may perform measurement reporting periodically. The UE200 may also perform measurement reporting for each event. In particular, in this embodiment, measurement reporting may be performed for virtual component carriers or virtual cells.

[0025] (2) Functional Block Configuration of the Wireless Communication System Next, the functional block configuration of the wireless communication system 10 will be described. Specifically, the functional block configurations of the base station 100 and UE200 will be described. Figure 2 is a functional block configuration diagram of the base station 100 (100A, 100B). Figure 3 is a functional block configuration diagram of the UE200.

[0026] (2.1) Base station As shown in Figure 2, the base station 100 includes a wireless communication unit 110, a virtual cell processing unit 120, a handover processing unit 130, and a control unit 140.

[0027] The wireless communication unit 110 transmits a downlink signal (DL signal) in accordance with 6G. The wireless communication unit 110 also receives an uplink signal (UL signal) in accordance with 6G. The wireless communication unit 110 may transmit the DL signal and receive the UL signal using one or more transmit / receive points (TRPs). In this embodiment, TRP may be interpreted as meaning multiple transmitting antennas for DL.

[0028] The virtual cell processing unit 120 performs processing such as setting up and managing virtual component carriers or virtual cells.

[0029] The virtual cell processing unit 120 can be interpreted as a setting unit that associates a first cell, composed of carriers in a first frequency band, with a second cell, composed of carriers in a second frequency band different from the first frequency band, as a set. The carriers of the first cell and the carriers of the second cell are associated as a single set and treated as a virtual component carrier or virtual cell. These single sets may be called by other names such as group, cluster, ensemble, unit, or cluster.

[0030] The carriers in the first frequency band and the carriers in the second frequency band are carriers that can be targeted for CA or DC. Therefore, the first cell is used as a cell or carrier to ensure connectivity between the terminal and the base station, while the second cell may be used as a cell or carrier that provides radio resources to the terminal in addition to the first cell. Specifically, a carrier in at least one frequency band may be a carrier that can be a PCC (Primary CC) in CA, and a carrier in another frequency band may be a carrier that can be an SCC (Secondary CC) in CA. Also, a cell in at least one frequency band may be a cell that can be a PCell (Primary Cell) in DC, and a cell in another frequency band may be a cell that can be an SCell (Secondary Cell) in DC. Multiple CCs / cells associated as a set are CCs that can be band-combined as CA, or cells that can be band-combined as DC. Note that CC may be used interchangeably with cell, in which case virtual component carrier has the same meaning as virtual cell.

[0031] The virtual cell processing unit 120 may notify the UE200 of virtual cell-related information using MIB / SIB information, etc. The virtual cell processing unit 120 also instructs the UE200 to configure virtual cell measurement settings for virtual cell measurement, and manages and processes the measurement result reports for virtual cells received from the UE200.

[0032] Furthermore, multiple CC / cells may all be CC / cells provided by the same base station, or some of the multiple CC / cells may be CC / cells provided by different base stations. If multiple CC / cells include CC / cells from other base stations, the virtual cell processing unit 120 may coordinate with the other base stations for virtual cell configuration.

[0033] If the base station has a CU-DU configuration, the virtual cell processing unit 120 may share its functions between the CU and the DU. Specifically, the virtual cell processing function within the DU may send virtual cell-related information to the CU when configuring a virtual cell. The virtual cell processing function within the CU may also request virtual cell-related information from the DU when attempting to configure a virtual cell for a specific UE. Furthermore, if the virtual cell includes CC / cells of other DUs, the virtual cell processing function within the DU may coordinate with other DUs for virtual cell configuration.

[0034] The handover processing unit 130 controls the handover of the UE200. Specifically, the handover processing unit 130 controls the handover of the UE200 from its serving cell to other nearby cells. A serving cell can be interpreted simply as the cell to which the UE200 is connected, but more precisely, in the case of an RRC connected UE (connection state at the Radio Resource Control Layer) where carrier aggregation (CA) is not configured, there is only one serving cell that constitutes the primary cell. In the case of an RRC connected UE configured with CA, a serving cell can be interpreted as representing one or more sets of cells including the primary cell and all secondary cells.

[0035] In particular, in this embodiment, the serving cell may be a virtual cell. The handover processing unit 130 can control the handover from a virtual cell acting as a serving cell of the UE200 to another virtual cell. The handover processing unit 130 may also control the handover from a cell of the UE200 to another virtual cell.

[0036] Furthermore, handover may include conditional handover (CHO) and / or dual active protocol stack (DAPS) handover. CHO allows a UE200-led handover to be performed when specific execution conditions are met. If CHO is not applicable, a normal handover may be performed (this may be called CHO recovery). Additionally, handover may include Layer 1 / Layer 2 mobility management (L1 / L2 mobility or LTM). In particular, in this embodiment, CHO or LTM can also be applied to virtual cells.

[0037] The control unit 140 controls each functional block that constitutes the gNB100. The control unit 140 can be interpreted as a control unit that assigns a set of a first cell, which consists of a carrier in the first frequency band, and a second cell, which consists of a carrier in a second frequency band different from the first frequency band, to the terminal. The control unit 140 assigns these wireless resources to the terminal as a set of the first cell and the second cell. In particular, in this embodiment, by assigning a set of multiple CC / cells that are subject to CA or DC to the terminal, high throughput CA / DA can be achieved at an early timing.

[0038] (2.2) UE200 As shown in Figure 3, the UE200 includes a wireless communication unit 210, a measurement processing unit 220, a handover execution unit 230, and a control unit 240.

[0039] The wireless communication unit 210 transmits an uplink signal (UL signal) in accordance with 6G. The wireless communication unit 210 also receives an uplink signal (DL signal) in accordance with 6G. The wireless communication unit 210 may also transmit and receive uplink / downlink signals in accordance with LTE / 4G or NR / 5G.

[0040] The wireless communication unit 210 may be interpreted as a receiving unit that receives information from the base station indicating that a first cell, composed of carriers in a first frequency band, and a second cell, composed of carriers in a second frequency band different from the first frequency band, are associated as a set.

[0041] The measurement processing unit 220 can measure the quality of the UE200 serving cell and its neighboring cells, and report the measurement results to the network (Measurement Report). The measurement processing unit 220 may also perform measurement reporting of the source cell and target cell during handover.

[0042] In particular, in this embodiment, the serving cell may be a virtual cell, and the neighboring cell may be a virtual cell adjacent to the virtual cell of the UE200. The measurement processing unit 220 may perform quality measurement of the virtual cell based on the virtual cell measurement setting information from the network and report the measurement results to the network. One or more of the options described later may be used for calculating the quality of the virtual cell, the selection criteria for the virtual cell, and the trigger for reporting the measurement results.

[0043] The quality of the object being measured may be, for example, the quality included in the Measurement Report as defined in 3GPP TS38.331 (e.g., RSRP, RSRQ, SINR). Specifically, the measurement processing unit 220 may receive the measurement signals used for the quality measurement. As mentioned above, the measurement signals may include SSB and CSI-RS. However, other reference signals (RS) may also be included.

[0044] The handover execution unit 230 executes the handover of the UE 200. Specifically, the handover execution unit 230 may execute the handover to the target cell based on the control by the gNB 100. The handover execution unit 230 can execute the processes related to the normal handover (legacy handover) and the conditional handover (CHO). In the case of CHO, it may transition to the candidate cell when the execution condition is satisfied. The execution condition may be determined based on the quality of the reference signal (RS), specifically, the values of RSRP, RSRQ, or SINR as described above. The target may or may not be accompanied by an SCG. In other words, the target cell may be a single cell or may be composed of a plurality of cells (which may be read as a cell group) according to DC.

[0045] In particular, in this embodiment, the handover execution unit 230 may execute the handover from a cell or a virtual cell to another virtual cell as the target. When the target cell is a virtual cell, even if some of the plurality of cells constituting the virtual cell have poor quality, if the quality of other cells is good, it can become the virtual cell of the transition destination according to the selection criteria of the virtual cell. Even in such a case, the handover may be executed with all the cells constituting the virtual cell as a set. Note that the cells with poor quality included in the target virtual cell may be set to the deactivate state once and may be changed to the activate state when the quality improves.

[0046] Also, the handover execution unit 230 can receive a handover command of the UE 200 from the network. In the present embodiment, the handover command may include an RRCReconfiguration of a target virtual cell. Also, the handover execution unit 230 can receive a cell switching command from the network in the case of LTM. In the present embodiment, the cell switching command may include a config ID of the virtual cell and a TA value.

[0047] The control unit 240 controls each functional block that constitutes the UE 200. In particular, in the present embodiment, the control unit 240 may execute control related to measurement settings and measurement reports for virtual cells by the measurement processing unit 220. Also, the control unit 240 may execute control of handover or cell switching for virtual cells by the handover execution unit 230.

[0048] (3) Operation of the wireless communication system (3.1) Problem In 4G and 5G mobile communications, CA or DC technology is used to increase throughput.

[0049] However, in CA, the UE first connects to the base station using the PCC, and then sequentially adds the second and subsequent SCCs according to instructions from the base station. Also, in DC, the UE first connects to the PCell of the master node MN, and then the master node MN requests the secondary node SN to add PSCell / SCell, obtains permission from the secondary node SN, and sequentially adds PSCell / SCell.

[0050] Therefore, in conventional CA and DC, it takes time to reach high throughput, so there is a problem that it is required to obtain high throughput at an earlier timing and it cannot meet the new needs of 6G.

[0051] (3.2) Virtual CC / Cell Configuration In this embodiment, in order for the UE200 to obtain high throughput at an earlier timing, multiple CCs / cells that can be targeted as CA or DC are combined and treated as a set. By assigning these as a set to a terminal, frequency bandwidth is allocated to the terminal.

[0052] In other words, a first cell consisting of carriers in the first frequency band and a second cell consisting of carriers in a second frequency band different from the first frequency band are associated as a set, and the first and second cells are assigned to the terminal as a set.

[0053] (3.2.1) Basic Concept Diagram 4 shows the basic concept of a virtual component carrier or virtual cell.

[0054] Multiple component carriers CC#1, CC#2, and CC#3 on the frequency axis are combined and treated as a single component carrier. These CC#1, CC#2, and CC#3 can be considered as CCs that can be band-combined as carrier aggregation (CA), or as CCs that can be band-combined as dual connectivity (DC). These CC#1, CC#2, and CC#3 can be treated virtually as a single component carrier CC#X, and may be called Virtual CC#X. Note that the number of CCs treated as a single unit is not limited to three; it can be two or more CCs.

[0055] Similarly, multiple cells, Cell#1, Cell#2, and Cell#3, are combined and treated as a single cell. These cells, Cell#1, Cell#2, and Cell#3, can be considered as cells that can be band-combined as carrier aggregation (CA), or as cells that can be band-combined as dual connectivity (DC). These cells, Cell#1, Cell#2, and Cell#3, can be virtually treated as a single cell, Cell#X, and may be called virtual cell #X. Note that the number of cells treated as a single unit is not limited to three; it can be two or more cells.

[0056] Here, "virtual" can be interpreted as meaning that a certain component carrier CC may be included in multiple virtual component carriers, and a certain cell may be included in multiple virtual cells. In this way, by combining them virtually, it becomes possible to flexibly configure multiple virtual component carriers or virtual cells.

[0057] Furthermore, of the multiple component carriers CC#1, CC#2, and CC#3 that constitute Virtual CC#X, at least one component carrier CC may be a PCC (Primary CC), and the other component carrier CCs may be SCCs (Secondary CCs). The PCC may be interpreted as a CC that receives downlink control signals and downlink data signals and transmits uplink control signals, uplink data signals, and random access signals at the UE200, or as a CC that ensures connectivity between the UE200 and the base station 100. In contrast, the SCC may be interpreted as receiving downlink control signals and downlink data signals and transmitting uplink data signals, but not transmitting uplink control signals or random access signals, or as a CC that provides radio resources in addition to the PCC. Furthermore, the frequency band for the PCC may be a frequency band that makes it easier to ensure coverage compared to the frequency band for the SCC, such as the 800MHz band, 2GHz band, or 3.7GHz band. Furthermore, the PCC frequency band may be interpreted as a frequency band with better quality compared to the SCC frequency band. In contrast, the SCC frequency band may utilize a high-bandwidth frequency band that enables high-speed communication.

[0058] Similarly, of the multiple cells Cell#1, Cell#2, and Cell#3 that make up the virtual cell Cell#X, at least one cell may be composed of a PCell, and the other cells may be composed of SPCells or SCells. A PCell may be interpreted as a cell that provides services to a PCC, and an SCell may be interpreted as a cell that provides services to an SCC. A PSCell may also be interpreted as a cell that provides services to the SN's PCC in the DC.

[0059] (3.2.2) Specific Example Figure 5 shows a specific example of virtual cell configuration.

[0060] As shown in Figure 5, Virtual cell A consists of cells #1, #2, and #3; Virtual cell B consists of cells #1, #2, and #4; Virtual cell C consists of cells #5, #2, and #6; and Virtual cell D consists of cells #5, #2, and #4.

[0061] Cell #1 is positioned as a PCell in both Virtual cell A and Virtual cell B, and Cell #5 is positioned as a PCell in both Virtual cell C and Virtual cell D.

[0062] Cells #2 through #4 and #6 are classified as PSCell / SCell. Cell #2 belongs to all virtual cells, cells #3 and #6 belong to only one virtual cell, and cell #4 belongs to two virtual cells, Virtual cells C and D.

[0063] For example, Cell #1 operates in the 2GHz frequency band, and Cell #5 operates in the 3.7GHz frequency band, providing wider coverage compared to the other cells, Cell #2, Cell #3, Cell #4, and Cell #6.

[0064] When configured as virtual cells in a DC, at least Cell #1 and Cell #5 are provided by the master node MN, and at least one of the remaining Cells is provided by the secondary node SN.

[0065] (3.3) Example of Operation (3.3.1) Method of Notifying the UE of Virtual Cell Information Figure 6 shows how to notify the UE200 of virtual cell-related information.

[0066] As shown in Figure 6, at S601, the base station 100 broadcasts virtual cell-related information to the subordinate UE200 using MIB / SIB information.

[0067] The base station may broadcast virtual cell-related information only in the PCell that constitutes the virtual cell, or it may broadcast virtual cell-related information in all cells that constitute the virtual cell. Here, broadcasting may mean a broadcast transmitted to an unspecified number of terminals.

[0068] Virtual cell-related information may be added to the information content of any existing SIB. Alternatively, a new SIBxx may be defined to broadcast virtual cell-related information. This newly defined SIBxx may target only UE200s that support virtual cells.

[0069] Virtual cell-related information may include at least all or part of the following:

[0070] • Virtual Cell List: This shows which BC (band combination) index each virtual cell corresponds to. Specifically, the virtual cell list shows that virtual cell A corresponds to BC index = 1, virtual cell B corresponds to BC index = 2, and so on.

[0071] - Virtual cell ID, PLMN ID, TAC ID, NPN-related information (CAG ID, NID)

[0072] • Virtual cell configuration: i) Option 1: Directly list the CCs or cells that make up the virtual cell. For example, for virtual cell A, indicate CC#1, CC#2, CC#3, or cell#1, cell#2, cell#3, or frequency information (ARFCN value). ii) Option 2: Indicate with the BC (band combination) index. For example, the combination pattern cell#1, cell#2, cell#3 is BC index=1, and the combination pattern cell#1, cell#2, cell#4 is BC index=2.

[0073] - Virtual cell access restriction information (virtual cell barred or virtual cell not barred)

[0074] - Information indicating a PCell within a virtual cell: For example, in the case of virtual cell A, it indicates that CC#1 or cell#1 is a PCell. It is optional to indicate that the remaining cells, cell#2 and cell#3, are SCells.

[0075] ・Information indicating the selection criteria for virtual cells: i) Option 1 The selection criterion for a virtual cell is whether the average quality of all cells constituting the virtual cell exceeds a predetermined threshold. For example, if the average quality of the three cells constituting virtual cell A (cell#1, cell#2, and cell#3) exceeds the predetermined threshold, virtual cell A is selected. This threshold may be q-RxLevMin_virtualCell or q-QualMin_virtualCell. ii) Option 2 The selection criterion for a virtual cell is the selection criterion for the PCell cell contained within the virtual cell. For example, the selection criterion for cell#1, which is a PCell contained within virtual cell A, is used as the selection criterion for virtual cell A. iii) Option 3 The selection criterion for a virtual cell is whether the average quality of the best N (the top N cells with the best quality) among the cells constituting the virtual cell exceeds a predetermined threshold. For example, if N=2, if the average quality of the top two cells with the best quality in virtual cell A exceeds the predetermined threshold, virtual cell A is selected.

[0076] • Neighboring virtual cell information: A neighboring virtual cell is any virtual cell that contains a cell from which a terminal can receive signals. This may include not only virtual cells containing geographically adjacent cells, but also cells containing cells that are not geographically adjacent. Furthermore, the above-mentioned cell may be a PCell.

[0077] - Information indicating the (re)selection priority of virtual cells: For example, assign a cellReselectionPrioirty between virtual cells A, B, C, and D and cells cell#1 to #6 (or CC#1 to #6) to assign a virtual cell (re)selection priority.

[0078] RACH information for accessing virtual cells

[0079] Information indicating that only UEs that support virtual cells may camp on.

[0080] As described above, according to this embodiment, the base station 100 can notify the UE200 of virtual cell-related information. Furthermore, the UE200 can recognize each cell that is band-combined as a virtual cell based on the received virtual cell-related information.

[0081] (3.3.2) Measurement method for virtual cells Figure 7 shows the measurement method for virtual cells.

[0082] As shown in Figure 7, in S701, the base station 100 instructs the UE200 to configure virtual cell measurement settings. For example, the MeagObject of the MeasConfig message includes information about the virtual cell measurement settings. The information about the virtual cell measurement settings may include at least all or part of the following:

[0083] • Multiple frequencies of a virtual cell: The measurement frequencies for multiple cells that make up each virtual cell are shown. For example, SSBFrequency#1 (ARFCN-value#1), SSBFrequency#2 (ARFCN-value#2), etc., may be shown.

[0084] - Multiple subcarrier spacings (SCS) of a virtual cell: For example, SCS#1 for frequency#1, SCS#2 for frequency#2, etc. may be shown.

[0085] - A predetermined threshold for calculating the quality of a virtual cell: This threshold may be used, for example, in the method for calculating the quality of a virtual cell (RSRP / RSRQ / SINR) described later, and the average quality (RSRP / RSRQ / SINR) of a cell or beam that exceeds the predetermined threshold may be considered as the quality of the virtual cell.

[0086] In S702, UE200 performs the virtual cell measurement process based on the virtual cell measurement settings information.

[0087] The method for calculating the quality of a virtual cell (RSRP / RSRQ / SINR) may be one of the following: i) Option 1: The average of the quality of all cells constituting the virtual cell (RSRP / RSRQ / SINR) is considered the quality of the virtual cell. ii) Option 2: The quality of the PCells (RSRP / RSRQ / SINR) included in the virtual cell is considered the quality of the virtual cell. The method for deriving the PCell quality may remain the same as before. iii) Option 3: The average value (RSRP / RSRQ / SINR) of the quality of the best N cells or beams that exceed a predetermined threshold is considered the quality of the virtual cell.

[0088] Furthermore, the UE200 uses the measurement gap set by the base station 100 when measuring virtual cells. The base station 100 may set the longest measurement gap for each frequency in the virtual cell as the measurement gap for the virtual cell. For example, if the measGap for frequency #1 is 1.5ms, the measGap for frequency #2 is 3ms, and the measGap for frequency #3 is 4ms, the measurement gap for the virtual cell is set to 4ms. This makes it possible to properly measure virtual cells containing multiple cells.

[0089] In S703, the UE200 performs measurement result reporting for the virtual cell. The measurement result report may also be included in the measResults of the MeasurementReport message. The measResults may include the quality of the virtual cell for each virtual cell ID, and may also include the quality of each cell that makes up the virtual cell, or the quality of each beam within each cell.

[0090] Measurement results may be reported periodically or at the time of an event. The trigger event for a virtual cell may be set to one of the following: i) Option 1: Event A3 / A4 (TimeToTrigger). The base station sets an event for measurement reporting for each cell included in the virtual cell. For example, for cells #1 to #3 that make up virtual cell A, event A3 for cell #1, event A4 for cell #2, and event A4 for cell #3 are set. When the events for all of these cells are satisfied, the UE200 considers that the measurement report for virtual cell A has been triggered and triggers the measurement report for virtual cell A. ii) Option 2: New event (new TtimeToTrigger). The base station sets a new event for measurement reporting for the virtual cell. This new event may consist of multiple sub-events. For example, for cells #1 to #3 contained in virtual cell A, the new event consists of sub-event A3 for cell #1, sub-event A4 for cell #2, and sub-event A4 for cell #3. The UE200 considers the new event to be satisfied when all the sub-events set for each cell contained in virtual cell A are satisfied, and triggers the measurement report for virtual cell A. Note that the above events Option 1 and 2 may also be applied to LTM's event-based L1 measurement reporting.

[0091] In summary, the UE200 receives configuration information from the base station containing the necessary information for virtual cell measurement reporting, which clarifies the method for measuring virtual cell quality and calculating quality for the UE200. Based on the virtual cell measurement configuration information, the UE200 can perform virtual cell quality measurements. Furthermore, the UE200 can report the virtual cell measurement results to the base station 100 when the trigger event is satisfied.

[0092] Furthermore, the base station 100 may include virtual cell measurement configuration information in the RRCRelease message to the UE200. By including this information in the RRCRelease message, the UE200 can perform virtual cell quality measurement when in the RRC_IDLE state. Then, when the UE200 transitions to the RRC_CONNECTED state, it can report the virtual cell measurement results, allowing for immediate virtual cell setup. The virtual cell measurement configuration information may include the virtual cell ID, the virtual cell's frequency and cell list, and predetermined quality thresholds. This allows for the measurement of cells and beams that exceed the predetermined thresholds.

[0093] (3.3.3) Inter-device coordination regarding virtual cell configuration (A) In the case of MN and SN, if some of the multiple cell cells that make up the virtual cell are cell cells provided by different base stations, it is necessary to coordinate the combination of bandwidth bands between base stations when configuring the virtual cell.

[0094] For example, if cell #3 is a cell provided by base station 100B among the cells cell #1, cell #2, and cell #3 that make up virtual cell A set up by base station 100A, then coordination with base station 100B is necessary to set up virtual cell A.

[0095] Figure 8 shows the sequence for coordinating the configuration of a virtual cell / CC between base stations. As shown in Figure 8, at S801, base station 100A, which will be the MN, transmits virtual cell-related information about the virtual cell that the MN intends to configure to base station 100B, which will be the SN, via the Xn interface. The virtual cell-related information may consist of all or part of the virtual cell-related information broadcast in the SIB / MIB in Figure 6. Based on this, base station 100B, which will be the SN, determines whether it is possible to configure the cell provided by base station 100B included in the virtual cell-related information as a virtual cell.

[0096] In S802, base station 100B, which acts as the SN, transmits the determination result to base station 100A, which acts as the MN, as virtual cell-related information. The virtual cell-related information may consist of all or part of the virtual cell-related information broadcast in the SIB / MIB shown in Figure 6, and if it is not acceptable to set some cells as virtual cells, it may also include information on other alternative cells.

[0097] (B) In the case of a CU, DU configuration, base station 100 may be composed of a CU and a DU. There are various options for the functional branching point between the CU and DU, and any of them is acceptable.

[0098] A CU and a DU may be connected one-to-one, but as shown in Figure 9, one CU may be connected to two DUs. The CU and DU are connected via an F1 interface. Additionally, the DUs may be connected to each other via a new interface.

[0099] (B-1) CU-DU diagram 10 shows the sequence (part 1) for adjusting the virtual cell / CC settings between the CU and DU.

[0100] As shown in Figure 10(a), in S1001, the DU sends an F1 setup request message containing virtual cell-related information for the virtual cell to be configured by the DU to the higher-level CU. This virtual cell-related information may consist of all or part of the virtual cell-related information broadcast in the SIB / MIB shown in Figure 6. This allows the CU to recognize which cell the virtual cell that the DU is trying to configure is composed of.

[0101] In S1002, when the CU receives virtual cell-related information, it sends an F1 setup response back to the DU.

[0102] Furthermore, as shown in Figure 10(b), at S1003, the DU sends a GNB-DU configuration update message containing virtual cell-related information about the changes and updates to the virtual cell to the higher-level CU. This allows the CU to recognize how the virtual cell is being changed or updated.

[0103] In S1004, when the CU receives an update to the virtual cell-related information, it sends a GNB-DU configuration update Ack to the DU. In this way, even when the base station is configured as a CU-DU, the CU can recognize each cell that makes up the virtual cell set up by the DU, and can appropriately handle virtual cells composed of multiple cell cells.

[0104] Figure 11 shows the sequence (part 2) for adjusting the virtual cell / CC settings between the CU and DU. As shown in Figure 11(a), in S1101, when the CU wants to set up a virtual cell for a specific UE, it sends a UE context setup request message containing virtual cell-related information to the subordinate DU. This virtual cell-related information may consist of all or part of the virtual cell-related information broadcast in the SIB / MIB in Figure 6. This allows the DU to determine whether the cell constituting the virtual cell that the CU intends to set up for the UE is configurable.

[0105] In S1102, the DU returns a UE context setup response to the CU, which includes the decision regarding the configuration of virtual cells for a specific UE. This decision may include alternative cell information if some cells are unacceptable for configuration as virtual cells.

[0106] Furthermore, as shown in Figure 11(b), in S1103, if there is a change in the configuration of the virtual cell set in the UE, the CU sends a UE context modification request message to the subordinate DU, which includes a request to change the virtual cell-related information. This allows the DU to determine whether the change to the virtual cell is acceptable to the UE.

[0107] In S1104, the DU sends a UE context modification response to the CU, which includes the decision result regarding the request to change the virtual cell's related information.

[0108] Thus, the CU can request the DU to configure or modify the virtual cell for a specific UE, and the DU can then configure or modify the virtual cell for that specific UE.

[0109] (B-2) DU-DU diagram 12 shows the sequence for adjusting the virtual cell / CC settings between DUs.

[0110] If some of the multiple cells that make up a virtual cell are provided by different DUs, then when configuring the virtual cell, it is necessary to adjust the combination of bandwidth bands between the DUs.

[0111] For example, if cell #3 is provided by DU2 among the cells cell #1, cell #2, and cell #3 that make up virtual cell A set up by DU1, then coordination with DU2 is necessary to set up virtual cell A.

[0112] As shown in Figure 12, at S1201, DU1 transmits information related to the virtual cell that DU1 intends to configure to DU2 via a new DU-DU interface. The virtual cell information may consist of all or part of the virtual cell information broadcast in the SIB / MIB shown in Figure 6. Based on this, DU2 determines whether it is possible to configure the cell provided by DU2 that is included in the virtual cell as a virtual cell.

[0113] In S1202, DU2 transmits the decision result to DU1 as virtual cell-related information. The virtual cell-related information may consist of all or part of the content of the virtual cell-related information reported in the SIB / MIB in Figure 6. In addition, if it is not acceptable to set some cells as virtual cells, the virtual cell-related information may include alternative cells.

[0114] The above describes the adjustment between DU1 and DU2 under the same CU1 as shown in Figure 9. However, the sequence in Figure 12 may also be applied to adjustments between DUs under different CUs, i.e., between DU2 and DU4. This allows for the exchange of virtual cell information set by CUs and DUs between CUs and DUs, making it possible to adjust the cells that constitute the virtual cells in the virtual cell settings.

[0115] (3.3.4) Mobility in UE virtual cells A UE200 that is allocated bandwidth in a virtual cell can perform handover or cell switching as follows:

[0116] Figure 13 shows the handover sequence between base stations. As shown in Figure 13, at S1301, the UE200 reports the measurement results regarding the quality of the virtual cell to the base station. Upon receiving the measurement report, if the source base station gNB determines that a handover of the UE200 is necessary, it may decide on the virtual cell as the new handover destination. Specifically, the base station gNB that provides services to the PCell contained in the virtual cell may be decided as the target base station gNB for the handover. In the case of CHO (Conditional Handover) or LTM (Lower layer Triggered Mobility), multiple candidate virtual cells may be decided.

[0117] In S1302, the source base station gNB sends a Handover request to the target base station gNB, including the target virtual cell ID and quality. In the case of CHO or LTM, the source base station NB may include multiple candidate virtual cells in the Handover request.

[0118] In S1303, the target base station gNB generates an RRCReconfiguration for the virtual cell to be handed over to. Specifically, it may be generated in one of the following ways: i) Option 1: Generate a single RRCReconfiguration by combining the RRCReconfigurations for each cell contained in the virtual cell. ii) Option 2: Generate an RRCReconfiguration for each cell contained in the virtual cell. For example, when handing over from virtual cell A, RRCReconfiguration#1, RRCReconfiguration#2, and RRCReconfiguration#3 may be generated for each cell cell#1, cell#2, and cell#3 contained in virtual cell A. Specifically, in Figure 5, when performing a handover from virtual cell A to virtual cell C, cell#1 as a PCell switches to cell#5 as a PCell, and cell#3 as an SCell switches to cell#6 as an SCell. Cell#2 as an SCell does not switch. Therefore, Option 2 generates RRCReconfiguration only for Cell#1 and Cell#3, where switching occurs. In other words, RRCReconfiguration for Cell#2, where no switching occurs, can be omitted. Note that in the case of CHO, execution conditions for virtual cells may be generated. Also, in the case of Conditional LTM, LTM execution conditions for virtual cells may be generated.

[0119] In S1304, the target base station gNB sends a Handover request ACK message to the source base station gNB, which includes the virtual cell's RRCReconfiguration.

[0120] In S1305, the source base station gNB sends a Handover command to UE200, including the virtual cell's RRCReconfiguration. In the case of CHO, the virtual cell's execution condition may be sent to the UE. In the case of Conditional LTM, the virtual cell's LTM execution condition may be sent to the UE. Upon receiving the Handover command, UE200 performs the handover to the virtual cell.

[0121] Figure 14 shows the cell switching sequence in LTM. As shown in Figure 14, at S1401, the source gNB-DU may instruct the virtual cell to perform early synchronization by issuing a PDCCH ordered RACH command.

[0122] In S1402, the UE may perform RACH on all cells of the target GNB-DU contained within the target virtual cell. In S1403 and S1404, the target gNB-DU may send a TA notification via the CU to the source gNB-DU, including Timing Advance values ​​for each cell contained within the virtual cell (for example, in the case of virtual cell A, TA values ​​for cell#1, TA values ​​for cell#2, and TA values ​​for cell#3).

[0123] Specifically, in Figure 5, when performing a cell switching from virtual cell A to target virtual cell C, cell #1 as a PCell switches to cell #5 as a PCell, and cell #3 as an SCell switches to cell #6 as an SCell. Cell #2 as an SCell does not switch. Therefore, it is acceptable to generate TA notifications that include TA values ​​for cell #5 and TA values ​​for cell #6 only for the cells that switch, Cell #5 and Cell #6.

[0124] In S1405, the UE200 reports the measurement results for the virtual cell to the source gNB-DU as an L1 measurement report. This report may include the virtual cell ID and quality. Based on the measurement results, the source gNB-DU can decide to cell switch to the target virtual cell (for example, virtual cell C in Figure 5). In S1406, the source gNB-DU sends a cell switching command to the UE200, which includes the virtual cell config ID of the target virtual cell and the TA values ​​for each cell contained within that virtual cell (for example, in the case of virtual cell C, the TA value for cell #5 and the TA value for cell #6).

[0125] This allows the UE200 to switch to the target virtual cell of the target gNB-DU. Note that the gNB can send a candidate Cell TCI state Activation / Deactivation MAC CE before LTM execution. In the case of a virtual cell, the candidate virtual cell ID may be included in the candidate cell TCI state activation / deactivation MAC CE sent from the gNB to the UE.

[0126] As described above, since the UE200 can exchange information including the virtual cell ID and quality necessary for virtual cell handover, it can properly perform virtual cell handover between the source base station 100A and the target base station 100B. Furthermore, since the UE200 can exchange information including the virtual cell Config ID and TA value necessary for virtual cell switching, it can properly perform virtual cell switching between the source gNB-DU and the target gNB-DU.

[0127] (4) Operation and Effects According to the base station of the above-described embodiment, a first cell composed of carriers in the first frequency band and a second cell composed of carriers in a second frequency band different from the first frequency band are associated as a set, and the first and second cells are assigned to the terminal as a set. As a result, the base station can assign the first and second cells as a set to the terminal, and can provide the terminal with high throughput at an early stage. Furthermore, according to the terminal of the above-described embodiment, the terminal receives information from the base station indicating that the first cell composed of carriers in the first frequency band and the second cell composed of carriers in a second frequency band different from the first frequency band are associated as a set, and receives the assignment of the first and second cells as a set. As a result, the terminal can assign the first and second cells as a set to the terminal, and can reach high throughput at an early stage.

[0128] (5) Other Embodiments Although the contents of the present invention have been described above in accordance with the embodiments, it will be obvious to those skilled in the art that the present invention is not limited to these descriptions and that various modifications and improvements are possible.

[0129] In this disclosure, multiple options and variations may be combined as a single option / variation.

[0130] The examples of operation described above may be combined and applied in combination, as long as no inconsistencies arise.

[0131] The block diagrams used in the description of the above embodiments show functional units. 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 coupled, or it may be realized using two or more physically or logically separated devices that are directly or indirectly connected (for example, using wired or wireless connections). A functional block may also be realized by combining software with the one or more of the above devices.

[0132] Functions include, but are not limited to, judgment, decision, judgment, calculation, calculation, processing, derivation, investigation, exploration, confirmation, reception, transmission, output, access, resolution, selection, selection, establishment, comparison, assumption, expectation, assumption, broadcasting, notifying, communicating, forwarding, configuring, reconfiguring, allocating (mapping), and assigning. For example, a functional block (configuration part) that enables transmission is called a transmitting unit or transmitter. In all cases, as mentioned above, the method of implementation is not particularly limited.

[0133] For example, the base stations 100A, 100B, and terminal 200 in one embodiment of the present disclosure may function as computers that process the wireless communication method of the present disclosure. Figure 15 is a diagram showing an example of the hardware configuration of the base stations 100A, 100B, and terminal 200 according to one embodiment of the present disclosure. The above-mentioned base stations 100A, 100B, and terminal 200 may be physically configured as computer devices including a processor 1001, memory 1002, storage 1003, communication device 1004, input device 1005, output device 1006, bus 1007, etc.

[0134] In the following explanation, the term "device" can be replaced with "circuit," "device," "unit," etc. The hardware configuration of base stations 100A, 100B and terminal 200 may include one or more of the devices shown in the diagram, or it may be configured without some of the devices.

[0135] Each function in the base stations 100A and 100B and the terminal 200 is realized by loading predetermined software (programs) onto hardware such as the processor 1001 and memory 1002, which allows the processor 1001 to perform calculations and control communication by the communication device 1004, or control at least one of the reading and writing of data in the memory 1002 and storage 1003.

[0136] The processor 1001 controls the entire computer, for example, by running an operating system. The processor 1001 may consist of a central processing unit (CPU) that includes interfaces with peripheral devices, control units, arithmetic units, registers, and so on.

[0137] Furthermore, the processor 1001 reads programs (program code), software modules, data, etc., from at least one of the storage 1003 and the communication device 1004 into the memory 1002 and executes various processes accordingly. The program used is one that causes the computer to execute at least a part of the operations described in the above embodiment. Furthermore, although it has been explained that the above processes are executed by one processor 1001, they may be executed simultaneously or sequentially by two or more processors 1001. The processor 1001 may be implemented by one or more chips. The program may also be transmitted from a network via a telecommunications line.

[0138] Memory 1002 is a computer-readable recording medium and may consist of at least one of the following: Read Only Memory (ROM), Erasable Programmable ROM (EPROM), Electrically Erasable Programmable ROM (EEPROM), Random Access Memory (RAM), etc. Memory 1002 may also be called a register, cache, main memory, etc. Memory 1002 can store executable programs (program code), software modules, etc., for carrying out a wireless communication method according to one embodiment of the present disclosure.

[0139] The storage 1003 is a computer-readable recording medium and may consist of at least one of the following: an optical disc such as a Compact Disc ROM (CD-ROM), a hard disk drive, a flexible disk, a magneto-optical disk (e.g., Compact Disc, Digital Multipurpose Disc, Blu-ray® Disc), a smart card, flash memory (e.g., a card, stick, key drive), a floppy® disk, a magnetic strip, etc. The storage 1003 may also be called an auxiliary storage device. The above-mentioned storage medium may be, for example, a database, server, or other suitable medium including at least one of memory 1002 and storage 1003.

[0140] The communication device 1004 is hardware (transceiver / receiver device) for communicating between computers via at least one of a wired network and a wireless network, and is also referred to as a network device, network controller, network card, communication module, etc. The communication device 1004 may be configured to include, for example, a high-frequency switch, duplexer, filter, frequency synthesizer, etc., in order to implement at least one of frequency division duplex (FDD) and time division duplex (TDD).

[0141] The input device 1005 is an input device that accepts input from an external source (e.g., a keyboard, mouse, microphone, switch, button, sensor, etc.). The output device 1006 is an output device that outputs to an external source (e.g., a display, speaker, LED lamp, etc.). The input device 1005 and the output device 1006 may be configured as an integrated unit (e.g., a touch panel).

[0142] Furthermore, each device, such as the processor 1001 and memory 1002, is connected by a bus 1007 for communicating information. The bus 1007 may be configured using a single bus, or different buses may be configured for each device.

[0143] Furthermore, the base station 100 and terminal 200 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), and a field programmable gate array (FPGA), and some or all of each functional block may be realized by such hardware. For example, the processor 1001 may be implemented using at least one of these hardware components.

[0144] Information notification is not limited to the embodiments described herein and may be carried out by other means. For example, information notification may be carried out by physical layer signaling (e.g., Downlink Control Information (DCI), Uplink Control Information (UCI)), upper 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 combinations thereof. RRC signaling may also be called RRC messages, and may be, for example, RRC Connection Setup messages, RRC Connection Reconfiguration messages, etc.

[0145] Each aspect / embodiment described herein may apply to systems utilizing Long Term Evolution (LTE), LTE-Advanced (LTE-A), SUPER 3G, IMT-Advanced, 4th generation mobile communication system (4G), 5th generation mobile communication system (5G), 6th generation mobile communication system (6G), xth generation mobile communication system (xG) (where x is, for example, an integer or decimal), Future Radio Access (FRA), New Radio (NR), New radio access (NX), Future generation radio access (FX), W-CDMA®, GSM®, CDMA2000, Ultra Mobile Broadband (UMB), IEEE 802.11 (Wi-Fi®), IEEE 802.16 (WiMAX®), IEEE 802.20, Ultra-WideBand (UWB), Bluetooth®, and other appropriate systems, as well as at least one of the next-generation systems that are extended, modified, created, or defined based thereon. Furthermore, multiple systems may be applied in combination (for example, a combination of at least one of LTE and LTE-A with 5G).

[0146] The processing procedures, sequences, flowcharts, etc., of each aspect / embodiment described in this disclosure may be reordered, provided they do not contradict each other. For example, the methods described in this disclosure present various step elements using exemplary order and are not limited to the specific order presented.

[0147] The specific operations described in this disclosure as being performed by a base station may, in some cases, be performed by its upper node. In a network consisting of one or more network nodes having a base station, it is clear that various operations performed for communication with a terminal can be performed by the base station and at least one other network node (for example, an MME or S-GW, but not limited to these). Although the above example illustrates the case where there is one other network node besides the base station, it may also be a combination of multiple other network nodes (for example, an MME and an S-GW).

[0148] Information and signals (such as data) can be output from a higher layer (or lower layer) to a lower layer (or higher layer). Input and output may occur via multiple network nodes.

[0149] Input and output information may be stored in a specific location (e.g., memory) or managed using a management table. Input and output information may be overwritten, updated, or appended to. Output information may be deleted. Input information may be transmitted to other devices.

[0150] The determination may be made by a value represented by one bit (0 or 1), by a boolean value (true or false), or by a numerical comparison (for example, by comparing with a predetermined value).

[0151] Each aspect / embodiment described in this disclosure may be used individually, in combination, or switched between as needed during implementation. Furthermore, notification of specific information (e.g., notification that "X is") is not limited to explicit notification, but may also be implicit (e.g., by not providing such notification).

[0152] Software should be broadly interpreted to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software modules, applications, software applications, software packages, routines, subroutines, objects, executable files, execution threads, procedures, functions, and so on, whether they are called software, firmware, middleware, microcode, hardware description languages, or by any other name.

[0153] Furthermore, software, instructions, information, etc., may be transmitted and received via a transmission medium. For example, if software is transmitted from a website, server, or other remote source using at least one of wired technology (such as coaxial cable, fiber optic cable, twisted pair, or digital subscriber line (DSL)) and wireless technology (such as infrared or microwave), then at least one of these wired and wireless technologies is included in the definition of a transmission medium.

[0154] The information, signals, etc. described in this disclosure may be represented using any of the various 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 voltage, current, electromagnetic waves, magnetic fields or magnetic particles, optical fields or photons, or any combination thereof.

[0155] In addition, terms used in this disclosure and terms necessary for understanding this disclosure may be replaced with terms having the same or similar meanings. For example, at least one of the channel and symbol may be a signal (signaling). Also, a signal may be a message. Furthermore, a component carrier (CC) may be called a carrier frequency, cell, frequency carrier, etc.

[0156] The terms “system” and “network” as used in this disclosure are interchangeable.

[0157] Furthermore, the information, parameters, etc., described in this disclosure may be expressed using absolute values, relative values ​​from a given value, or other corresponding information. For example, wireless resources may be indicated by an index.

[0158] The names used for the parameters described above are not restrictive in any way. Furthermore, the formulas and other expressions using these parameters may differ from those expressly disclosed in this disclosure. Various channels (e.g., PUCCH, PDCCH, etc.) and information elements can be identified by any suitable name, and therefore, the various names assigned to these various channels and information elements are not restrictive in any way.

[0159] In this disclosure, terms such as "Base Station (BS)", "wireless base station", "fixed station", "NodeB", "eNodeB (eNB)", "gNodeB (gNB)", "access point", "transmission point", "reception point", "transmission / reception point", "cell", "sector", "cell group", "carrier", and "component carrier" may be used interchangeably. Base stations may also be referred to by terms such as macrocell, small cell, femtocell, and picocell.

[0160] A base station can house one or more (e.g., three) cells (also called sectors). If a base station houses multiple cells, the entire coverage area of ​​the base station can be divided into multiple smaller areas, each of which may be provided with communication services by a base station subsystem (e.g., a Remote Radio Head, RRH). The terms "cell" or "sector" refer to part or all of the coverage area of ​​at least one of the base station and / or base station subsystems providing communication services in that coverage.

[0161] In this disclosure, the transmission of information by a base station to a terminal may be interpreted as the base station instructing the terminal to perform control or operation based on the information.

[0162] In this disclosure, terms such as “terminal,” “user terminal,” “Mobile Station (MS),” and “User Equipment (UE)” may be used interchangeably.

[0163] 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 several other appropriate terms.

[0164] 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 also be a device mounted on a mobile body, the mobile body itself, etc. The mobile body refers to a movable object, and its speed of movement is arbitrary. This also includes the case when the mobile body is stationary. The mobile body includes, but is not limited to, vehicles, transport vehicles, automobiles, motorcycles, bicycles, connected cars, excavators, bulldozers, wheel loaders, dump trucks, forklifts, trains, buses, handcarts, rickshaws, ships and other watercraft, airplanes, rockets, satellites, drones (registered trademark), multicopters, quadcopters, balloons, and items mounted on them. The mobile body may also be a mobile body that moves autonomously based on operation commands. It may be a vehicle (e.g., a car, an airplane, etc.), an unmanned mobile body (e.g., a drone, an autonomous vehicle, etc.), or a robot (manned or unmanned). Furthermore, at least one of the base station and the mobile station may include devices that do not necessarily move during communication operations. For example, at least one of the base station and the mobile station may be an Internet of Things (IoT) device such as a sensor.

[0165] Furthermore, the term "base station" in this disclosure may be interpreted as "terminal." For example, the various aspects / embodiments of this disclosure may be applied to a configuration in which communication between a base station and a terminal is replaced with communication between multiple terminals (which may be called, for example, Device-to-Device (D2D), Vehicle-to-Everything (V2X), etc.). In this case, the terminal 200 may have the functions that the base station 100A or 100B has. Also, terms such as "uplink" and "downlink" may be interpreted as terms corresponding to terminal-to-terminal communication (for example, "side"). For example, uplink channel, downlink channel, etc., may be interpreted as side channel.

[0166] Similarly, the term "terminal" in this disclosure may be replaced with "base station." In this case, the functions of the terminal 200 described above may be provided by the base station 100A or 100B.

[0167] Figure 16 shows an example of the configuration of vehicle 2001. As shown in Figure 16, vehicle 2001 includes a drive unit 2002, a steering unit 2003, an accelerator pedal 2004, a brake pedal 2005, a shift lever 2006, left and right front wheels 2007, left and right rear wheels 2008, an axle 2009, an electronic control unit 2010, various sensors 2021 to 2029, an information service unit 2012, and a communication module 2013.

[0168] The drive unit 2002 is composed of, for example, an engine, a motor, or a hybrid of an engine and a motor.

[0169] The steering unit 2003 includes at least a steering wheel (also called a handle) and is configured to steer at least one of the front wheels and the rear wheels based on the operation of the steering wheel, which is operated by the user.

[0170] The electronic control unit 2010 consists of a microprocessor 2031, memory (ROM, RAM) 2032, and communication ports (IO ports) 2033. Signals from various sensors 2021 to 2027 installed in the vehicle are input to the electronic control unit 2010. The electronic control unit 2010 may also be called an Electronic Control Unit (ECU).

[0171] Signals from various sensors 2021 to 2029 include current signals from the current sensor 2021 that senses motor current, front and rear wheel rotation speed signals obtained by the rotation speed sensor 2022, front and rear wheel air pressure signals obtained by the air pressure sensor 2023, vehicle speed signals obtained by the vehicle speed sensor 2024, acceleration signals obtained by the acceleration sensor 2025, accelerator pedal depression signals obtained by the accelerator pedal sensor 2029, brake pedal depression signals obtained by the brake pedal sensor 2026, shift lever operation signals obtained by the shift lever sensor 2027, and detection signals obtained by the object detection sensor 2028 for detecting obstacles, vehicles, pedestrians, etc.

[0172] The Information Services Unit 2012 consists of various devices for providing (outputting) various types of information such as driving information, traffic information, and entertainment information, including car navigation systems, audio systems, speakers, televisions, and radios, and one or more ECUs that control these devices. The Information Services Unit 2012 uses information acquired from external devices via communication modules 2013, etc., to provide various multimedia information and multimedia services to the occupants of the vehicle 2001.

[0173] The Information Services Unit 2012 may include input devices that accept input from external sources (e.g., keyboards, mice, microphones, switches, buttons, sensors, touch panels, etc.) and output devices that output to external sources (e.g., displays, speakers, LED lamps, touch panels, etc.).

[0174] The driver assistance system unit 2030 consists of various devices that provide functions to prevent accidents or reduce the driver's workload, such as millimeter-wave radar, Light Detection and Ranging (LiDAR), cameras, positioning locators (e.g., GNSS), map information (e.g., high-definition (HD) maps, autonomous vehicle (AV) maps), gyro systems (e.g., Inertial Measurement Unit (IMU), Inertial Navigation System (INS)), Artificial Intelligence (AI) chips, and AI processors, as well as one or more ECUs that control these devices. The driver assistance system unit 2030 also sends and receives various information via the communication module 2013 to realize driver assistance functions or autonomous driving functions.

[0175] The communication module 2013 can communicate with the microprocessor 2031 and components of the vehicle 2001 via its communication port. For example, the communication module 2013 sends and receives data via the communication port 2033 between the drive unit 2002, steering unit 2003, accelerator pedal 2004, brake pedal 2005, shift lever 2006, left and right front wheels 2007, left and right rear wheels 2008, axle 2009, the microprocessor 2031 and memory (ROM, RAM) 2032 in the electronic control unit 2010, and sensors 2021 to 2029 provided in the vehicle 2001.

[0176] The communication module 2013 is a communication device that can be controlled by the microprocessor 2031 of the electronic control unit 2010 and can communicate with external devices. For example, it can send and receive various types of information to and from external devices via wireless communication. The communication module 2013 may be located either inside or outside the electronic control unit 2010. The external device may be, for example, a base station or a mobile station.

[0177] The communication module 2013 may transmit at least one of the following to an external device via wireless communication: signals from the various sensors 2021 to 2029 input to the electronic control unit 2010, information obtained based on said signals, and information based on input from an external source (user) obtained via the information service unit 2012. The electronic control unit 2010, the various sensors 2021 to 2029, the information service unit 2012, etc., may also be called input units that accept input. For example, the PUSCH transmitted by the communication module 2013 may include information based on the above input.

[0178] The communication module 2013 receives various information (traffic information, signal information, vehicle-to-vehicle information, etc.) transmitted from external devices and displays it on the information service unit 2012 installed in the vehicle. The information service unit 2012 may also be called an output unit, which outputs information (for example, it outputs information to devices such as displays and speakers based on the PDSCH (or data / information decoded from the PDSCH) received by the communication module 2013).

[0179] Furthermore, the communication module 2013 stores various information received from external devices in memory 2032, which is available to the microprocessor 2031. Based on the information stored in memory 2032, the microprocessor 2031 may control the drive unit 2002, steering unit 2003, accelerator pedal 2004, brake pedal 2005, shift lever 2006, left and right front wheels 2007, left and right rear wheels 2008, axles 2009, sensors 2021 to 2029, etc., which are provided in the vehicle 2001.

[0180] As used in this disclosure, the terms “determining” and “determining” may encompass a wide variety of actions. “Determining” may include, for example, judging, calculating, computing, processing, deriving, investigating, looking up, searching, or inquiring (e.g., searching in a table, database, or other data structure), or ascertaining. “Determining” may also include receiving (e.g., receiving information), transmitting (e.g., sending information), inputting, outputting, or accessing (e.g., accessing data in memory). Furthermore, “determining” may include resolving, selecting, choosing, establishing, or comparing. In other words, "judgment" and "decision" can include considering that some action has been "judged" or "decided." Also, "judgment (decision)" can be reinterpreted as "assuming," "expecting," or "considering."

[0181] The terms “connected,” “coupled,” and any variations thereof mean 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” with each other. The coupling or connection between elements may be physical, logical, or a combination thereof. For example, “connection” may be reinterpreted as “access.” As used in this disclosure, two elements may be considered to be “connected” or “coupled” with each other using at least one of one or more wires, cables, and printed electrical connections, and, in some non-limiting and non-exclusive examples, electromagnetic energy having wavelengths in the radio frequency domain, microwave domain, and optical (both visible and invisible) domain.

[0182] The reference signal may also be abbreviated as RS, and may be called Pilot depending on the applicable standard.

[0183] In this disclosure, the phrase "based on" does not mean "based solely on" unless otherwise specified. In other words, the phrase "based on" means both "based solely on" and "based at least on."

[0184] Any reference to elements using the designations “first,” “second,” etc., as 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 way to distinguish between two or more elements. Accordingly, references to the first and second elements do not imply that only two elements may be employed, or that the first element must precede the second element in any way.

[0185] In the configuration of each of the above devices, "means" may be replaced with "part," "circuit," "device," etc.

[0186] Where the terms “include,” “including,” and variations thereof are used in this disclosure, these terms are intended to be inclusive, as is the term “comprising.” Furthermore, the term “or” as used in this disclosure is not intended to mean exclusive OR.

[0187] A wireless frame may consist of one or more frames in the time domain. Each of these frames in the time domain may be called a subframe. A subframe may further consist 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.

[0188] Numerology may be communication parameters applied to at least one of the transmission and reception of a signal or channel. Numerology may include, for example, at least one of the following: subcarrier spacing (SCS), bandwidth, symbol length, cyclic prefix length, transmission time interval (TTI), number of symbols per TTI, radio frame configuration, specific filtering processes performed by the transceiver in the frequency domain, and specific windowing processes performed by the transceiver in the time domain.

[0189] A slot may consist of one or more symbols in the time domain (such as Orthogonal Frequency Division Multiplexing (OFDM) symbols or Single Carrier Frequency Division Multiple Access (SC-FDMA) symbols). A slot may also be a time unit based on neurology.

[0190] A slot may include multiple mini-slots. Each mini-slot may consist of one or more symbols in the time domain. Mini-slots may also be called sub-slots. Mini-slots may consist of fewer symbols than a slot. A PDSCH (or PUSCH) transmitted in a time unit larger than a mini-slot may be called a PDSCH (or PUSCH) mapping type A. A PDSCH (or PUSCH) transmitted using a mini-slot may be called a PDSCH (or PUSCH) mapping type B.

[0191] Wireless frames, subframes, slots, minislots, and symbols all represent units of time when transmitting a signal. Different names may be used for each of these terms.

[0192] 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. In other words, at least one of a subframe and a TTI may be a subframe (1 ms) in existing LTE, a period shorter than 1 ms (e.g., 1 to 13 symbols), or a period longer than 1 ms. Note that the unit representing the TTI may be called a slot, minislot, etc., instead of a subframe.

[0193] Here, TTI refers to, for example, the smallest unit of time for scheduling in wireless communication. For example, in an LTE system, the base station schedules each terminal to allocate radio resources (such as the frequency bandwidth and transmission power available to each terminal) in TTI units. However, the definition of TTI is not limited to this.

[0194] TTI may be a transmission time unit for channel-encoded data packets (transport blocks), code blocks, code words, etc., or it may be a processing unit for scheduling, link adaptation, etc. Note that when a TTI is given, the actual time interval (e.g., number of symbols) in which the transport block, code block, code word, etc. are mapped may be shorter than the given TTI.

[0195] Furthermore, if one slot or one mini-slot is referred to as TTI, then one or more TTIs (i.e., one or more slots or one or more mini-slots) may constitute the minimum time unit of scheduling. In addition, the number of slots (number of mini-slots) that constitute the minimum time unit of scheduling may be controlled.

[0196] A TTI with a time length of 1 ms may also be called a normal TTI (TTI in LTE Rel. 8-12), a long TTI, a normal subframe, a long subframe, or a slot. A TTI shorter than a normal TTI may also be called a shortened TTI, a short TTI, a partial or fractional TTI, a shortened subframe, a short subframe, a mini slot, a subslot, or a slot.

[0197] Furthermore, long TTIs (e.g., normal TTIs, subframes, etc.) may be interpreted as TTIs with a time length exceeding 1 ms, and short TTIs (e.g., shortened TTIs, etc.) may be interpreted as TTIs with a TTI length less than that of a long TTI but 1 ms or more.

[0198] A resource block (RB) is a resource allocation unit in the time domain and frequency domain, and in the frequency domain, it may contain one or more consecutive subcarriers. The number of subcarriers in an RB may be the same regardless of the neurology, for example, 12. The number of subcarriers in an RB may be determined based on the neurology.

[0199] Furthermore, the time domain of RB may contain one or more symbols and may be the length of one slot, one minislot, one subframe, or one TTI. One TTI, one subframe, etc., may each consist of one or more resource blocks.

[0200] One or more RBs may also be called Physical RBs (PRBs), Sub-Carrier Groups (SCGs), Resource Element Groups (REGs), PRB pairs, RB pairs, etc.

[0201] Furthermore, a resource block may consist of one or more resource elements (REs). For example, one RE may be a radio resource area comprising one subcarrier and one symbol.

[0202] A Bandwidth Part (BWP), also known as a partial bandwidth, may represent a subset of consecutive common resource blocks (RBs) for a given neurology in a given carrier. Here, the common RBs may be identified by an index of the RBs relative to the carrier's common reference point. The PRBs may be defined and numbered within a given BWP.

[0203] A BWP may include BWPs for UL (UL BWP) and BWPs for DL ​​(DL BWP). One or more BWPs may be configured within a single carrier for a UE.

[0204] At least one of the configured BWPs may be active, and the UE does not need to assume that it will send or receive a given signal / channel outside of the active BWP. In this disclosure, terms such as "cell" and "carrier" may be read as "BWP".

[0205] The structures described above, such as wireless frames, subframes, slots, minislots, and symbols, are merely illustrative. For example, the number of subframes included in a wireless frame, the number of slots per subframe or wireless 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, and the number of symbols, symbol length, and cyclic prefix (CP) length within a TTI can be varied in various ways.

[0206] The term "maximum transmit power" as used in this disclosure may mean the maximum transmit power, the nominal UE maximum transmit power, or the rated UE maximum transmit power.

[0207] In this disclosure, if articles are added through translation, such as a, an, and the in English, this disclosure may include the fact that the noun following these articles is plural.

[0208] In this 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 "combine" may be interpreted similarly to "different."

[0209] Although the present disclosure has been described in detail above, it will be clear to those skilled in the art that the present disclosure is not limited to the embodiments described herein. The present disclosure can be implemented in modified and altered forms without departing from the intent and scope of the present disclosure as defined by the claims. Therefore, the descriptions in the present disclosure are illustrative and not intended to be restrictive in any way.

[0210] 10 Wireless communication system 20 Network 100A, 100B Base station 110 Wireless communication unit 120 Virtual cell processing unit 130 Handover processing unit 140 Control unit 200 Terminal 210 Wireless communication unit 220 Measurement processing unit 230 Handover execution unit 240 Control unit 1001 Processor 1002 Memory 1003 Storage 1004 Communication device 1005 Input device 1006 Output device 1007 Bus 2001 Vehicle 2002 Drive unit 2003 Steering unit 2004 Accelerator pedal 2005 Brake pedal 2006 Shift lever 2007 Left and right front wheels 2008 Left and right rear wheels 2009 Axle 2010 Electronic control unit 2012 Information service unit 2013 Communication module 2021 Current sensor 2022 Rotation speed sensor 2023 Air pressure sensor 2024 Vehicle speed sensor 2025 Acceleration sensor 2026 Brake pedal sensor 2027 Shift lever sensor 2028 Object detection sensor 2029 Accelerator pedal sensor 2030 Driver assistance system unit 2031 Microprocessor 2032 Memory (ROM, RAM) 2033 Communication port (IO port)

Claims

1. A base station comprising: a setting unit that associates a first cell, composed of carriers in a first frequency band, and a second cell, composed of carriers in a second frequency band different from the first frequency band, as a set; and a control unit that assigns the first cell and the second cell as a set to a terminal.

2. The base station according to claim 1, wherein, when multiple frequency band carriers are aggregated, the first cell is a cell that ensures connectivity between the terminal and the base station, and the second cell is a cell that provides radio resources to the terminal in addition to the first cell.

3. The base station according to claim 1, characterized in that the carrier in the first frequency band has broader coverage than the carrier in the second frequency band.

4. The base station according to claim 1, characterized in that both the first cell and the second cell are cells provided by the base station.

5. The base station according to claim 1, characterized in that the second cell is a cell provided by a second base station different from the base station.

6. A terminal comprising a receiving unit that receives information from a base station indicating that a first cell, composed of carriers in a first frequency band, and a second cell, composed of carriers in a second frequency band different from the first frequency band, are associated as a set, and a control unit that receives the first cell and the second cell as a set.

7. A communication method for a base station comprising the steps of: associating a first cell, which consists of carriers in a first frequency band, and a second cell, which consists of carriers in a second frequency band different from the first frequency band, as a set; and assigning the first cell and the second cell as a set to a terminal.

8. A system comprising a base station and a terminal, wherein the base station includes a setting unit that associates a first cell, which is composed of a carrier in a first frequency band, and a second cell, which is composed of a carrier in a second frequency band different from the first frequency band, as a set, and a control unit that assigns the first cell and the second cell as a set to the terminal.

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