terminal

Abstract

The terminal (200) includes a receiving unit (220) that receives setting information of a migration destination cell from a gNB (100A) based on a conditional cell migration in a gNB (100A) where the terminal (200) resides, and a control unit (250) that performs migration to the migration destination cell without receiving a migration command based on the setting information of the migration destination cell. When the receiving unit (220) receives change information indicating whether the setting information of the migration destination cell has been changed, the control unit (250) changes the setting information of the migration destination cell based on the change information.

Description

Technical Field

[0001] The present invention relates to a terminal for performing wireless communication, and more particularly, to a terminal for performing cell migration without waiting for a migration command. Background Art

[0002] In the 3rd Generation Partnership Project (3GPP), Long Term Evolution (LTE) was standardized, and LTE-Advanced (hereinafter referred to as LTE including LTE-Advanced) was standardized for the purpose of further speeding up LTE. In addition, in 3GPP, the specifications of the successor system of LTE, such as 5G or New Radio (NR), were further studied.

[0003] In the conventional handover (HO) process, the network determines a target radio base station (also called a target cell) based on quality information such as a measurement report sent from a terminal, and after preparing for the handover, a handover command (relocation command) is sent to the terminal.

[0004] However, when the terminal passes an appropriate switching point during the preparation process for switching on the network side, there is a problem of momentary interruption of the wireless link because it migrates directly to the target wireless base station without receiving a switching command from the source wireless base station (also called the source cell).

[0005] Therefore, in order to solve this problem, a process called Conditional HO (conditional cell relocation) has been studied (Non-patent Document 1). In Conditional HO, the network notifies the terminal of candidate cell configuration information including candidate cells of the Conditional HO destination and relocation conditions to the candidate cells.

[0006] When the transition condition to the candidate cell is satisfied, the terminal transitions to the target radio base station for which the transition condition to the candidate cell is set without waiting for a handover command from the source radio base station. This can avoid instantaneous interruption of the radio link.

[0007] Prior art literature

[0008] Non-patent literature

[0009] Non-patent document 1: "New WID: NR mobility enhancements", RP-190489, 3GPP TSG RAN Meeting #83, 3GPP, March 2019 Summary of the invention

[0010] However, in Conditional HO, when the terminal migrates to the target radio base station based on the setting information of the candidate cell, there is the following problem.

[0011] Specifically, when the configuration of the source radio base station is changed, the terminal may need to change the setting information of the candidate cells in accordance with the change, or may not need to change the setting information of the candidate cells.

[0012] However, the terminal cannot recognize whether or not the configuration information of the candidate cells held by the terminal needs to be updated in accordance with the change in the configuration of the source radio base station.

[0013] Therefore, regardless of the need to update the candidate cell configuration information, the terminal may not update the candidate cell configuration information stored in the terminal. In this case, the terminal may not be able to perform appropriate cell relocation.

[0014] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a terminal capable of performing appropriate cell relocation even when relocation to the relocation destination cell is performed without receiving a relocation command based on setting information of the relocation destination cell.

[0015] A terminal (terminal 200) involved in one embodiment of the present invention includes: a receiving unit (receiving unit 220), which receives, in a migration source cell (for example, gNB 100A) in which the terminal resides, setting information of a migration destination cell (for example, gNB 100B) from the migration source cell based on conditional cell migration; and a control unit (control unit 250), which performs migration to the migration destination cell without receiving a migration command based on the setting information of the migration destination cell, and when the receiving unit receives change information indicating whether the setting information of the migration destination cell has changed, the control unit changes the setting information of the migration destination cell based on the change information.

[0016] According to the present invention, even when a terminal executes a relocation to a relocation target cell without receiving a relocation command based on setting information of the relocation target cell, it is possible to execute appropriate cell relocation. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a diagram schematically showing the overall structure of the wireless communication system 10 .

[0018] Figure 2 It is a functional block diagram of the terminal 200.

[0019] Figure 3This is a diagram showing the sequence of the Conditional HO procedure (action example 1).

[0020] Figure 4 This is a diagram for explaining the structure of RRC Reconfiguration in the Conditional HO process.

[0021] Figure 5 This is a diagram showing the operation flow of the terminal 200 in the operation example 1 of the Conditional HO procedure.

[0022] Figure 6 This is a diagram showing the sequence of the Conditional HO procedure (action example 2).

[0023] Figure 7 This is a diagram showing the operation flow of the terminal 200 in the operation example 2 of the Conditional HO procedure.

[0024] Figure 8 This is a diagram showing the operation flow of the terminal 200 in operation example 3 of the Conditional HO procedure.

[0025] Fig. 9 It is a diagram schematically showing the overall configuration of the wireless communication system 10a.

[0026] Fig.10 This is a diagram showing the sequence of the Conditional SCG Change process (action example 1).

[0027] Fig.11 This is a diagram showing the sequence of the Conditional SCG Change process (action example 2).

[0028] Fig.12 It is a diagram showing an example of the hardware configuration of the terminal 200 . DETAILED DESCRIPTION

[0029] Hereinafter, the embodiments will be described based on the drawings. In addition, the same or similar reference numerals are given to the same functions and structures, and the description thereof will be appropriately omitted.

[0030] (1) Overall schematic structure of wireless communication system

[0031] Figure 1The wireless communication system 10 according to the present embodiment is a general structure diagram. The wireless communication system 10 is a wireless communication system based on the New Radio (NR), and includes a Next Generation-Radio Access Network (NG-RAN, not shown) and a terminal 200. In addition, the terminal is also called a user equipment (UE).

[0032] NG-RAN includes radio base stations 100A, 100B, and 100C (hereinafter referred to as gNBs 100A, 100B, and 100C). In addition, the specific structure of the wireless communication system 10 including the number of gNBs and terminals is not limited to Figure 1 Example shown.

[0033] NG-RAN actually includes multiple NG-RAN nodes, specifically, gNB (or ng-eNB), which is connected to the core network (5GC, not shown) based on NR. In addition, NG-RAN and 5GC can also be simply expressed as "network".

[0034] gNB 100A, 100B, and 100C are wireless base stations based on NR, and perform wireless communication based on NR with terminal 200. Each of gNB 100A, 100B, and 100C and terminal 200 can support Massive MIMO (Massive MIMO) that generates a beam with higher directivity by controlling wireless signals sent from multiple antenna elements, Carrier Aggregation (CA) that bundles and uses multiple component carriers (CCs), and Dual Connection (DC) that simultaneously communicates between multiple NG-RAN nodes and terminals. In addition, CC can also be called a carrier.

[0035] gNB 100A, 100B, and 100C each form one or more cells. Terminal 200 can migrate between cells (also referred to as wireless base stations) formed by gNB 100A, 100B, and 100C. In addition, "migrating between cells formed by gNB 100A, 100B, and 100C" can be expressed as "migrating between gNB 100A, 100B, and 100C" or "migrating between wireless base stations 100A, 100B, and 100C".

[0036] The so-called "migration" typically refers to switching between cells or switching between gNBs, but it may also include cell reselection, or the behavior of the terminal 200 such as changing the destination cell or destination gNB.

[0037] The cell (radio base station) of the migration destination to which the terminal 200 is to migrate is referred to as a target cell or a target radio base station. Also, the cell (radio base station) of the migration source is referred to as a source cell or a source radio base station.

[0038] In the wireless communication system 10, the terminal 200 can perform handover (cell relocation) according to conditional handover (hereinafter referred to as Conditional HO) without waiting for a handover command (relocation command). Conditional HO may also be simply referred to as CHO.

[0039] In addition, the wireless communication system 10 may include an Evolved Universal Terrestrial Radio Access Network (E-UTRAN) instead of NG-RAN. In this case, the E-UTRAN includes a plurality of E-UTRAN nodes, specifically, a plurality of eNBs (or en-gNBs), connected to a core network (EPC) based on LTE.

[0040] (2) Functional block structure of wireless communication system

[0041] Next, the functional block structure of the wireless communication system 10 is described. Specifically, the functional block structure of the terminal 200 is described. Hereinafter, only the parts related to the features in this embodiment are described. Therefore, the terminal 200 also has other functional blocks that are not directly related to the features in this embodiment.

[0042] Figure 2 2 is a functional block diagram of the terminal 200. Figure 2 As shown, the terminal 200 includes a transmitting unit 210 , a receiving unit 220 , a holding unit 230 , and a control unit 250 .

[0043] The transmitting unit 210 transmits an uplink (UL signal) based on NR. The receiving unit 220 receives a downlink signal (DL signal) based on NR. Specifically, the transmitting unit 210 and the receiving unit 220 perform wireless communication with gNBs 100A to 100C via a control channel or a data channel.

[0044] The transmission unit 210 transmits a radio resource control (RRC) message. For example, the transmission unit 210 transmits an RRC reconfiguration complete message (RRC Reconfiguration Complete).

[0045] The receiving unit 220 receives an RRC message. For example, the receiving unit receives an RRC reconfiguration message (RRCReconfiguration).

[0046] The receiving unit 220 receives setting information of a migration destination cell (candidate cell, for example, gNB 100B, gNB 100C) from the cell (for example, gNB 100A) where the terminal 200 resides based on ConditionalHO. In addition, the cell where the terminal 200 resides is also called a migration source cell.

[0047] The storage unit 230 stores setting information of the relocation destination cell (candidate cell) and the configuration of the relocation source cell (GNB 100A).

[0048] The control unit 250 controls each functional block constituting the terminal 200 .

[0049] When the receiving unit 220 receives the RRC Reconfiguration, the control unit 250 decodes the setting information of the relocation target cell (candidate cell) included in the RRC Reconfiguration. When the decoding of the setting information of the relocation target cell (candidate cell) is successful, the control unit 250 causes the storage unit 230 to store the setting information.

[0050] The control unit 250 performs the relocation to the relocation target cell (candidate cell) based on Conditional HO stored in the storage unit 230 without receiving a relocation command.

[0051] Specifically, the control unit 250 monitors the conditions for migration to the migration destination cell (candidate cell) based on the setting information of the migration destination cell (candidate cell) held in the holding unit 230. In addition, "monitoring the conditions for migration to the migration destination cell" can also be expressed as "evaluating the conditions for migration to the migration destination cell".

[0052] When the conditions for transition to the transition destination cell (candidate cell) are met, the control unit 250 performs a random access (RA) procedure between the terminal 200 and the transition destination cell (candidate cell), and transitions to the transition destination cell (candidate cell).

[0053] As described below, when the control unit 250 receives RRCReconfiguration from the gNB 100A during the Conditional HO process, it updates the setting information of the candidate cell maintained in the maintenance unit 230.

[0054] As described below, when the control unit 250 receives RRCReconfiguration from the gNB 100A during the Conditional HO process, it updates the configuration of the gNB 100A (measConfig, CHOcondition config, etc.) maintained in the retention unit 230.

[0055] As described below, when the control unit 250 receives RRCReconfiguration from the gNB 100A during the Conditional HO process, it obtains the change information in the RRC Reconfiguration. Based on the obtained change information, the control unit 250 determines whether the RRC Reconfiguration includes the setting information of the new candidate cell.

[0056] When the RRC Reconfiguration includes the setting information of new candidate cells, the control unit 250 updates the setting information of the candidate cells stored in the storage unit 230 .

[0057] On the other hand, when the RRC Reconfiguration does not include setting information of the new candidate cell, the control unit 250 updates the configuration (measConfig, CHO condition config, etc.) of the gNB 100A maintained in the retention unit 230.

[0058] When updating the configuration information of the candidate cells, the control unit 250 deletes all the configuration information of the candidate cells (old CHO configuration) stored in the storage unit 230 and applies the configuration information of the new candidate cells (new CHO configuration) (full config).

[0059] When the receiving unit 220 receives change information indicating "whether the setting information of the candidate cell (CHO configuration) is updated or the configuration of gNB 100A (measConfig / CHO condition config) is updated", the control unit 250 updates only the changed part (delta config) according to the change information.

[0060] When the receiving unit 220 receives change information indicating "whether the setting information of each candidate cell (CHO configuration) is updated or the configuration of gNB 100A (measConfig / CHO condition config) is updated", the control unit 250 updates only the changed part (delta config) according to the change information.

[0061] When the receiving unit 220 receives the change information indicating whether the setting information of the relocation destination cell (candidate cell) has been changed, the control unit 250 changes the setting information of the relocation destination cell (candidate cell) according to the change information. The change information indicates whether the setting information of each relocation destination cell (candidate cell) has been changed.

[0062] (3) Operation of wireless communication system

[0063] Next, the operation of the wireless communication system 10 will be described. Specifically, the Conditional HO process will be described.

[0064] (3.1) (Action Example 1)

[0065] Figure 3 FIG. 1 is a diagram showing the timing of the Conditional HO process (action example 1). Figure 3 As shown, when gNB100A (source cell) discovers gNB 100B and 100C based on the measurement report received from terminal 200, it sends a Conditional HO request (CHO request) (S11) to gNB 100B and 100C. gNB 100B and 100C are candidate cells that are candidates for the migration destination cell based on Conditional HO. In addition, the number of candidate cells is not limited to 2, and can also be 1 or 3 or more.

[0066] When gNB 100B (candidate cell) receives a CHO request from gNB 100A, it sends a CHO request ACK (CHO request ACK) which is a positive response to the CHO request to gNB 100A (S13). The CHO request ACK includes the setting information of the candidate cell. The setting information of the candidate cell includes the information of the candidate cell and the migration conditions to the candidate cell.

[0067] Similarly, when gNB 100C (candidate cell) receives a CHO request from gNB 100A, it sends a positive response to the CHO request, i.e., a CHO request ACK (S13), to gNB 100A. The CHO request ACK includes the configuration information of the candidate cell. The configuration information of the candidate cell includes the information of the candidate cell and the migration conditions to the candidate cell.

[0068] Through such processing, gNB 100B and 100C are set as candidate cells for the Conditional HO destination of terminal 200.

[0069] When gNB 100A receives CHO request ACK from gNB 100B and 100C, after completing the setting of the candidate cell, it sends RRC Reconfiguration (S15) to terminal 200. RRC Reconfiguration includes the setting information of the candidate cell sent from gNB100B and 100c respectively and the configuration of gNB100A. In addition, the reception of RRC Reconfiguration is also called the reception of the CHO command.

[0070] Figure 4 This is a diagram for explaining the structure of RRC Reconfiguration in the Conditional HO process.

[0071] like Figure 4 As shown, RRC Reconfiguration includes an RRC reconfiguration list (RRCReconfigurationList) as an information element. RRCReconfigurationList includes "configuration for cell1 (configuration for cell 1)" and "configuration for cell2 (configuration for cell 2)". In addition, the number of configurations for cell is not limited to two.

[0072] In this structure, when gNB 100A receives the setting information of the candidate cell from gNB 100B, it includes the setting information in configuration for cell1 in RRCReconfigurationList. Similarly, when gNB 100A receives the setting information of the candidate cell from gNB 100C, it includes the setting information in configuration for cell2 in RRCReconfigurationList.

[0073] In addition, RRCReconfigurationList is also called CHO configuration.

[0074] return Figure 3 When receiving RRC Reconfiguration from gNB 100A, terminal 200 obtains the setting information of the candidate cell and the configuration of gNB 100A in RRC Reconfiguration. When terminal 200 obtains the setting information of the candidate cell, it monitors the migration condition (CHO condition) to the candidate cell according to the setting information (S17). Specifically, terminal 200 determines whether the migration condition to the candidate cell contained in the setting information of each candidate cell is met.

[0075] While the CHO condition is being monitored by the terminal 200, when the configuration (Source configuration) of gNB 100A is changed in gNB 100A (S19), gNB 100A resends a Conditional HO request (CHO request) to gNB 100B and 100C along with the change (S21).

[0076] In Action Example 1, the change in the configuration of gNB 100A is related to the setting information of the candidate cell, so gNB 100A needs to send a Conditional HO request (CHO request) to gNB 100B and 100C again. The configuration of gNB 100A includes, for example, bearer configuration, radio resource configuration, etc.

[0077] After the configuration of gNB 100A is changed, if terminal 200 can migrate to gNB 100B, gNB 100B (candidate cell) sends a positive response to the CHO request, i.e., a CHO request response (CHO request ACK) (S23) to gNB 100A. CHO request ACK includes the setting information of the new candidate cell.

[0078] Similarly, after the configuration of gNB 100A is changed, if terminal 200 can also migrate to gNB 100C, gNB 100C (candidate cell) sends a positive response to the CHO request, i.e., a CHO request ACK (CHO request ACK) (S23) to gNB 100A. CHO request ACK includes the setting information of the new candidate cell.

[0079] When receiving CHO request ACK from gNB 100B and 100C, gNB 100A transmits RRC Reconfiguration (S25) to terminal 200 after completing the setting of candidate cells. RRC Reconfiguration includes setting information of new candidate cells transmitted from gNB 100B and 100c, respectively.

[0080] When receiving RRC Reconfiguration again from gNB 100A, terminal 200 obtains the setting information of the new candidate cell in RRC Reconfiguration. As described below, terminal 200 updates the setting information of the candidate cell and monitors the migration condition (CHO condition) to the candidate cell based on the setting information of the new candidate cell.

[0081] When the terminal 200 determines that the migration condition to the candidate cell is met (S27) by the movement of the terminal 200, etc., it does not receive a switching command from the gNB 100A, but decides to start switching (HO) to the candidate cell. The candidate cell of the migration destination that meets the migration condition is also called a CHO cell. In this embodiment, the CHO cell is gNB 100B.

[0082] When the terminal 200 decides to start HO to the candidate cell, a random access (RA) process is performed between the gNB 100B and the terminal 200, and synchronization is established between the gNB 100B and the terminal 200 (S29). As a result, the terminal 200 is connected to the gNB 100B.

[0083] When the RA process is successful, the terminal 200 sends RRC ReconfigurationComplete to the gNB 100B, for example.

[0084] In addition, in S13, gNB 100A may receive only the information of the candidate cell from gNB 100B and 100C. In this case, gNB 100A sets the migration conditions to the candidate cell. In addition, in this case, the setting information of the candidate cell includes the information of the candidate cell and the migration conditions to the candidate cell set by gNB 100A.

[0085] (3.1.1) Terminal Action

[0086] Next, the operation of the terminal 200 in the operation example 1 of the Conditional HO procedure is described.

[0087] Figure 5FIG. 2 is a diagram showing the operation flow of the terminal 200 in the operation example 1 of the Conditional HO process. Figure 5 As shown, terminal 200 receives new RRC Reconfiguration (S41) from gNB 100A.

[0088] When receiving RRC Reconfiguration from gNB 100A, terminal 200 updates the setting information of the candidate cell (S43). Specifically, terminal 200 deletes all the setting information of the candidate cell maintained and applies the setting information of the new candidate cell in RRC Reconfiguration. In this case, terminal 200 can replace the setting information of the candidate cell maintained with the setting information of the new candidate cell in RRC Reconfiguration.

[0089] Terminal 200 may delete the stored RRCReconfigurationList and apply the new RRCReconfigurationList in RRCReconfiguration. In this case, terminal 200 may replace the stored RRCReconfigurationList with the new RRCReconfigurationList in RRC Reconfiguration.

[0090] (3.2) Action Example 2

[0091] Figure 6 This is a diagram showing the sequence of the Conditional HO procedure (action example 2). Figure 6 S51~S57, S63 and S65 Figure 3 S11 to S17, S27 and S29 are the same, so the description is omitted.

[0092] While the CHO condition is being monitored by the terminal 200, when the configuration of gNB 100A (Source configuration) is changed in gNB 100A (S59), RRC Reconfiguration (S61) is sent to the terminal 200. RRC Reconfiguration includes the changed configuration of gNB 100A.

[0093] In Action Example 2, the change in the configuration of gNB 100A is not associated with the setting information of the candidate cell, so gNB100A does not send a Conditional HO request (CHO request) to gNB 100B and 100C again. The configuration of gNB 100A is, for example, measConfig, CHO condition config (Event A3, A5, B1, etc.), etc.

[0094] In addition, Event A3 is an event for measuring the state that "the value of the radio quality of the candidate cell is greater than the value obtained by adding an offset to the value of the radio quality of the cell where the terminal 200 resides". Event A5 is an event for measuring the state that "the value of the radio quality of the cell where the terminal 200 resides becomes worse than the threshold 1, and the value of the radio quality of the candidate cell becomes better than the threshold 2". Event B1 is an event for measuring the state that "the value of the radio quality of the candidate cell becomes higher than the threshold".

[0095] When the terminal 200 receives RRC Reconfiguration from the gNB 100A again, it obtains the changed configuration of the gNB 100A within the RRCReconfiguration.

[0096] (3.2.1) Terminal Action

[0097] Next, the operation of the terminal 200 in the operation example 2 of the Conditional HO procedure is described.

[0098] Figure 7 FIG. 2 is a diagram showing the operation flow of the terminal 200 in the operation example 2 of the Conditional HO process. Figure 7 As shown, the terminal 200 receives a new RRC Reconfiguration (S71) from the gNB 100A.

[0099] When receiving RRC Reconfiguration from gNB 100A, terminal 200 updates the configuration of gNB 100A (measConfig, CHO condition config, etc.) (S73). Specifically, terminal 200 deletes the configuration of gNB 100A that is maintained, and applies the setting information of the configuration of gNB 100A that is changed in RRC Reconfiguration. In this case, terminal 200 can replace the configuration of gNB 100A that is maintained with the configuration of gNB 100A that is changed in RRC Reconfiguration.

[0100] (3.3) Action Example 3

[0101] In action example 3, when gNB 100A sends RRC Reconfiguration to terminal 200 again ( Figure 3 S25 and Figure 6 S61) sends change information indicating "which of the setting information of the new candidate cell and the changed configuration of gNB100A is included in the RRC Reconfiguration" to the terminal 200. gNB 100A includes the change information in the RRC Reconfiguration. In addition, gNB 100A can send the change information to the terminal 200 separately from the RRC Reconfiguration.

[0102] Figure 8 FIG. 2 is a diagram showing the operation flow of the terminal 200 in the operation example 3 of the Conditional HO process. Figure 8 As shown, terminal 200 receives new RRC Reconfiguration (S81) from gNB 100A.

[0103] When receiving RRC Reconfiguration from gNB 100A, terminal 200 obtains the change information in RRC Reconfiguration. Based on the obtained change information, terminal 200 determines whether RRC Reconfiguration includes setting information (CHO configuration) of a new candidate cell (S83).

[0104] When the RRC Reconfiguration includes the setting information of the new candidate cell (CHO configuration), the terminal 200 deletes all the setting information of the candidate cell held and applies the setting information of the new candidate cell in the RRC Reconfiguration (S85). In this case, the terminal 200 may replace the setting information of the candidate cell held with the setting information of the new candidate cell in the RRC Reconfiguration.

[0105] Terminal 200 may delete the stored RRCReconfigurationList and apply a new RRCReconfigurationList in RRCReconfiguration. In this case, terminal 200 may replace the stored RRCReconfigurationList with the new RRCReconfigurationList in RRC Reconfiguration.

[0106] On the other hand, when the setting information (CHO configuration) of the new candidate cell is not included in the RRC Reconfiguration, the terminal 200 deletes the configuration of the gNB 100A maintained and applies the setting information of the configuration of the gNB 100A after the change in the RRC Reconfiguration (S87). In this case, the terminal 200 can replace the configuration of the gNB 100A maintained with the configuration of the gNB 100A after the change in the RRC Reconfiguration.

[0107] (3.4) Others

[0108] In Action Example 3, gNB 100A sends change information to terminal 200 indicating "which of the setting information of the new candidate cell and the changed configuration of gNB 100A is included in RRC Reconfiguration", but is not limited to this.

[0109] For example, gNB 100A may send change information to terminal 200 indicating "which of the setting information of the changed candidate cell within RRCReconfigurationList (i.e., the setting information of the changed candidate cell among the setting information of multiple candidate cells) and the updated configuration of gNB 100A is included in RRC Reconfiguration".

[0110] In this case, in S85, terminal 200 replaces only the setting information of the candidate cells after the change in RRCReconfigurationList among the setting information of the candidate cells being held.

[0111] In addition, gNB 100A can send change information to the terminal 200, indicating "which of the setting information of the changed candidate cell in the RRCReconfigurationList and the updated configuration of gNB 100A in the entire configuration of gNB 100A is included in the RRC Reconfiguration."

[0112] In this case, in S87, the terminal 200 replaces only the updated configuration of gNB 100A among all the maintained configurations of gNB 100A.

[0113] (4) Action and Effect

[0114] According to the above-described embodiment, when receiving the change information indicating whether the setting information of the relocation target cell has been changed, the terminal 200 changes the setting information of the relocation target cell according to the change information.

[0115] With this configuration, the terminal can reliably update the setting information of the candidate cells, and thus can perform appropriate cell migration.

[0116] According to the above-described embodiment, the change information indicates whether or not the setting information of each relocation destination cell has been changed.

[0117] With this configuration, the terminal 200 does not need to update all the setting information of the relocation target cell, and thus the power of the terminal 200 can be saved.

[0118] (5) Modification

[0119] The above-mentioned embodiment can also be applied to a conditional SCG change (Conditional SCG Change: CSC). In addition, CSC is also called "conditional PSCell change (Conditional PSCell change)" or "conditional PSCell addition (Conditional PSCell addition)".

[0120] Fig. 9 FIG. 1 is a schematic diagram of the overall structure of the wireless communication system 10a according to the present embodiment. Fig. 9 As shown, the NG-RAN (not shown) includes wireless base stations 110A, 110B, 110C, and 110D (hereinafter referred to as gNBs 110A, 110B, 110C, and 110D). In addition, the specific structure of the wireless communication system 10a including the number of gNBs and terminals is not limited to Fig. 9 Example shown.

[0121] In NR, cells are classified as follows.

[0122] The group of cells associated with the gNB (also called the master node (MN)) that "provides the control plane connected to the core network" is called the master cell group (MCG). The MCG consists of a primary cell (hereinafter referred to as PCell) and one or more secondary cells (hereinafter referred to as SCell). PCell is a cell used by the terminal to start the initial connection with the MN. In addition, MCG can also be composed of PCell only.

[0123] The group of cells associated with a gNB (also called a secondary node (SN)) that "does not provide a control plane connected to the core network but provides additional resources to the terminal" is called a secondary cell group (SCG). The SCG is composed of a primary SCell (hereinafter referred to as PSCell) and one or more SCells. The PSCell is a cell used by the terminal to start the initial connection with the SN. In addition, the SCG can also be composed of only the PSCell.

[0124] In addition, PCell is also called a special cell (SpCell) in MCG. In addition, PSCell is also called a SpCell in SCG.

[0125] In this embodiment, gNB 110A constitutes MN, and gNBs 110B, 110C, and 110D constitute SN. In this case, terminal 200 is connected to gNB 110A (MN) and one of gNBs 110B, 110C, and 110D (SN) and performs DC.

[0126] In DC, the terminal 200 can migrate between cells formed by gNB 110B, 110C, and 110D (SN) while being connected to gNB 110A (MN). In addition, "migrating between cells formed by gNB 110B, 110C, and 110D (SN)" can also be expressed as "migrating between PSCells formed by gNB 110B, 110C, and 110D (SN)" or "migrating between gNB 110B, 110C, and 110D (SN)" or "migrating between wireless base stations 110B, 110C, and 110D".

[0127] The so-called "migration" typically refers to switching between cells or switching between gNBs, but it may also include SN changes, such as changes in the connection destination cell (PSCell) or the connection destination gNB (SN), and other such behaviors of the terminal 200.

[0128] The cell (radio base station) of the migration destination to which the terminal 200 is to migrate is referred to as a target cell or a target radio base station. In addition, the SN of the migration destination to which the terminal 200 is to migrate is referred to as a target SN. In this embodiment, gNB 110C or gNB 110D is the target SN.

[0129] On the other hand, the cell (radio base station) of the migration source is referred to as the source cell or source radio base station. The SN of the migration source is referred to as the source SN. In this embodiment, gNB 110B is the source SN.

[0130] In the wireless communication system 10a, the terminal 200 performs an SN change called a conditional SCG change in DC. In addition, the Conditional SCG change may be abbreviated as CSC.

[0131] The wireless communication system 10a may include an Evolved Universal Terrestrial Radio Access Network (E-UTRAN) instead of NG-RAN. In this case, the E-UTRAN includes a plurality of E-UTRAN nodes, specifically, a plurality of eNBs (or en-gNBs), connected to a core network (EPC) based on LTE.

[0132] (5.1) Action Example 1

[0133] Fig.10 1 is a diagram showing the timing of the Conditional SCG Change process (action example 1). Fig.10 As shown, gNB 110A sends an SN Addition Request (S111) to gNB 110C and 110D (candidate cells) other than gNB 110B (source cell).

[0134] When gNB 110C (candidate cell) receives SN Addition Request from gNB 110A, it sends a positive response to SN Addition Request, i.e., SN Addition Request ACK (S113), to gNB 110A. SN Addition Request ACK includes the setting information of the candidate cell. The setting information of the candidate cell includes the information of the candidate cell and the migration conditions to the candidate cell.

[0135] Similarly, when gNB 110D (candidate cell) receives the SN Addition Request from gNB 110A, it sends a positive response to the SN Addition Request, i.e., an SN Addition Request ACK (S113), to gNB 110A. The SN Addition Request ACK includes the setting information of the candidate cell. The setting information of the candidate cell includes the information of the candidate cell and the migration conditions to the candidate cell.

[0136] Through this processing, gNB 110C and 110D are set as candidate cells for the Conditional SCG Change destination of terminal 200.

[0137] When gNB 110A receives SN Addition Request ACK from gNB 110C and 110D, it sends an SN Release Request (SN Release Request) to gNB 110B (source cell) after completing the setting of the candidate cell (S115). When gNB110B (source cell) receives SN Release Request, it sends SN Release RequestAck to gNB 110A (MN), stops sending data to terminal 200, and releases SN resources (S117).

[0138] When gNB 110A receives SN Release Request Ack from gNB 110B (source cell), it sends RRC Reconfiguration (S119) to terminal 200. RRC Reconfiguration includes the setting information of the candidate cells sent from gNB 110C and 110D respectively. In addition, the reception of RRC Reconfiguration is also called the reception of CSC command.

[0139] When receiving RRC Reconfiguration from gNB 110A, terminal 200 obtains the setting information of the candidate cell and the configuration of gNB 110A in RRC Reconfiguration. When terminal 200 obtains the setting information of the candidate cell, it monitors the migration condition (CSC condition) to the candidate cell according to the setting information (S121). Specifically, terminal 200 determines whether the migration condition to the candidate cell contained in the setting information of each candidate cell is met.

[0140] While the CSC condition is being monitored by the terminal 200, when the configuration (MN configuration) of gNB 110A is changed in gNB 110A (S123), gNB 110A re-sends SNAddition Request to gNB 110C and 110D along with the change (S125).

[0141] In Action Example 1, the change in the configuration of gNB 110A is related to the setting information of the candidate cell, so gNB 110A needs to send SN Addition Request again to gNB 110C and 110D. The configuration of gNB 110A is, for example, bearer config, radio resource config, etc.

[0142] After the configuration of gNB 110A is changed, if terminal 200 can migrate to gNB 110C, gNB 110C (candidate cell) sends SN Addition Request ACK to gNB 110A (S127). SN Addition Request ACK includes the setting information of the new candidate cell.

[0143] Similarly, after the configuration of gNB 110A is changed, if terminal 200 can migrate to gNB 110D, gNB110D (candidate cell) sends SN Addition Request ACK to gNB 110A (S127). SN Addition Request ACK includes the setting information of the new candidate cell.

[0144] When receiving SN Addition Request ACK from gNB 110C and 110D, gNB 110A transmits RRC Reconfiguration (S129) to terminal 200 after completing the setting of candidate cells. RRC Reconfiguration includes setting information of new candidate cells respectively transmitted from gNB 110C and 110D.

[0145] When receiving RRC Reconfiguration again from gNB 110A, terminal 200 obtains the setting information of the new candidate cell in RRCReconfiguration. As described below, terminal 200 updates the setting information of the candidate cell and monitors the migration condition (CSC condition) to the candidate cell based on the setting information of the new candidate cell.

[0146] When the terminal 200 determines that the migration condition to the candidate cell is met (S131) ​​by the movement of the terminal 200, etc., it does not receive an instruction from the gNB 110A, but decides to start the SN change to the candidate cell. The candidate cell of the migration destination that meets the migration condition is also called a CSC cell. In this embodiment, the CSC cell is gNB 110C.

[0147] When terminal 200 decides to start SN change to the candidate cell, a random access (RA) process is performed between gNB 110C and terminal 200, and synchronization is established between gNB 110C and terminal 200 (S133). Thus, terminal 200 is connected to gNB 110C.

[0148] When the RA process is successful, the terminal 200 sends RRC ReconfigurationComplete to gNB 110C, for example.

[0149] In addition, in S113, gNB 110A may receive only the information of the candidate cell from gNB 110C and 110D. In this case, gNB 110A sets the migration condition to the candidate cell. In addition, in this case, the setting information of the candidate cell includes the information of the candidate cell and the migration condition to the candidate cell set by gNB 110A.

[0150] The operation of the terminal 200 in the operation example 1 of the Conditional SCG Change process is the same as the terminal operation described above (3.1.1).

[0151] (5.2) Action Example 2

[0152] Fig.11 This is a diagram showing the sequence of the Conditional SCG Change process (action example 2). Fig.11 S151~S161, S167 and S169 Fig.10 S111 to S121, S131 and S133 are the same, so the description is omitted.

[0153] While the CSC condition is being monitored by the terminal 200, when the configuration of the gNB 110A (MN configuration) is changed in the gNB 110A (S163), RRC Reconfiguration (S165) is sent to the terminal 200. The RRC Reconfiguration includes the changed configuration of the gNB 110A.

[0154] In Action Example 2, the change in the configuration of gNB 110A is not associated with the setting information of the candidate cell, so gNB110A does not send SN Additon Request again to gNB 110C and 110D. The configuration of gNB 110A is, for example, measConfig, CHO condition config (Event A3, A5, B1, etc.), etc.

[0155] When terminal 200 receives RRC Reconfiguration from gNB 110A again, it obtains the changed configuration of gNB 110A within RRCReconfiguration.

[0156] The operation of the terminal 200 in the operation example 2 of the Conditional SCG Change procedure is the same as the terminal operation in (3.2.1) described above. In addition, as the operation of the terminal 200 in the modified example of the Condition SCG Change procedure, the terminal operations in (3.3) and (3.4) described above can be applied.

[0157] This variant can be applied to the case where there is a change in the configuration of gNB 110B. In this case, it is also possible to separately deal with whether the change in the configuration of gNB 110B is related to the setting information of the candidate cell, as implemented.

[0158] (6) Other Implementation Methods

[0159] As mentioned above, although the content of this invention was demonstrated based on embodiment, this invention is not limited to these descriptions, and it is obvious to a person skilled in the art that various deformation|transformation and improvement can be made.

[0160] For example, in the above-mentioned implementation, NR is used as an example, but Conditional HO and Conditional SCG Change can also be applied to LTE, and the same actions can be performed in LTE.

[0161] The block diagram used in the description of the above-mentioned embodiment ( Figure 2 ) shows blocks in units of functions. These functional blocks (structural parts) are implemented by any combination of at least one of hardware and software. In addition, there is no particular limitation on the implementation method of each functional block. That is, each functional block can be implemented using a device that is physically or logically combined, or two or more physically or logically separated devices can be directly or indirectly connected (for example, using wires, wirelessly, etc.) and implemented using these multiple devices. The functional block can also be implemented by combining software with the above-mentioned one device or the above-mentioned multiple devices.

[0162] Functionally, it includes judging, deciding, determining, calculating, calculating, processing, deriving, investigating, searching, confirming, receiving, sending, outputting, accessing, solving, selecting, selecting, establishing, comparing, assuming, expecting, regarding, broadcasting, notifying, communicating, forwarding, configuring, reconfiguring, allocating, mapping, assigning, etc., but is not limited to these. For example, the functional block (structural part) that enables the sending function is called a transmitting unit or a transmitter. In short, as mentioned above, there is no particular limitation on the implementation method.

[0163] Furthermore, the above-mentioned terminal 200 may also function as a computer that performs the processing of the wireless communication method of the present disclosure. Fig.12 FIG. 1 is a diagram showing an example of the hardware structure of the device. Fig.12 As shown, the device may also be configured as a computer device including a processor 1001, a memory 1002 (memory), a storage 1003 (storage), a communication device 1004, an input device 1005, an output device 1006, and a bus 1007.

[0164] In the following description, the word "device" may be replaced by "circuit", "device", "unit", etc. The hardware structure of the device may include one or more of the devices shown in the figure, or may exclude some of the devices.

[0165] Each functional block of the device is implemented by any hardware element of the computer device or a combination of the hardware elements.

[0166] In addition, each function in the device is implemented by the following method: predetermined software (program) is read into hardware such as processor 1001 and memory 1002, so that processor 1001 performs calculations and controls the communication of communication device 1004 or controls at least one of the reading and writing of data in memory 1002 and storage 1003.

[0167] The processor 1001 controls the entire computer by, for example, executing an operating system. The processor 1001 may be constituted by a central processing unit (CPU) including an interface with peripheral devices, a control device, a calculation device, a register, and the like.

[0168] In addition, the processor 1001 reads a program (program code), a software module or data, etc. from at least one of the memory 1003 and the communication device 1004 to the memory 1002, and performs various processes accordingly. As a program, a program that causes a computer to perform at least a part of the actions described in the above-mentioned embodiments is used. In addition, with respect to the above-mentioned various processes, although it is described that the above-mentioned various processes are performed by one processor 1001, the above-mentioned various processes can also be performed simultaneously or sequentially by more than two processors 1001. The processor 1001 can also be installed by more than one chip. In addition, the program can also be sent from the network via a telecommunication line.

[0169] The memory 1002 is a computer-readable recording medium, and may be composed of at least one of a read-only memory (ROM), an erasable programmable ROM (EPROM), an electrically erasable programmable ROM (EEPROM), a random access memory (RAM), etc. The memory 1002 may also be referred to as a register, a cache, a main memory (main storage device), etc. The memory 1002 may store a program (program code), a software module, etc. that can execute a method according to an embodiment of the present disclosure.

[0170] The memory 1003 is a computer-readable recording medium, and may be composed of at least one of an optical disk such as a CD-ROM (Compact Disc ROM), a hard disk drive, a floppy disk, a magneto-optical disk (e.g., a compressed disk, a digital versatile disk, a Blu-ray (registered trademark) disk, a smart card, a flash memory (e.g., a card, a stick, a key drive), a Floppy (registered trademark) disk, a magnetic strip, etc. For example, the memory 1003 may also be referred to as an auxiliary storage device. The above-mentioned storage medium may be, for example, other appropriate media such as a database, a server, etc. that includes at least one of the memory 1002 and the memory 1003.

[0171] The communication device 1004 is hardware (transceiver) used to communicate between computers via at least one of a wired network and a wireless network, and may also be called a network device, a network controller, a network card, a communication module, etc.

[0172] The communication device 1004 may be configured to include a high-frequency switch, a duplexer, a filter, a frequency synthesizer, etc., for example, in order to realize at least one of frequency division duplex (FDD) and time division duplex (TDD).

[0173] The input device 1005 is an input device that receives input from the outside (e.g., a keyboard, a mouse, a microphone, a switch, a button, a sensor, etc.). The output device 1006 is an output device that implements output to the outside (e.g., a display, a speaker, an LED light, etc.). In addition, the input device 1005 and the output device 1006 may also be integrally formed (e.g., a touch panel).

[0174] In addition, the processor 1001 and the memory 1002 and other devices are connected via a bus 1007 for communicating information. The bus 1007 may be configured using a single bus or may be configured using different buses for each device.

[0175] In addition, the device may be configured to include hardware such as a microprocessor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a programmable logic device (PLD), a field programmable gate array (FPGA), etc., and a part or all of each functional block may be implemented by the hardware. For example, the processor 1001 may also be installed using at least one of these hardware.

[0176] In addition, the notification of information is not limited to the form / implementation method described in the present disclosure, and other methods may also be used. For example, the notification of information may be implemented through physical layer signaling (e.g., downlink control information (Downlink Control Information: DCI), uplink control information (Uplink Control Information: UCI)), high-level signaling (e.g., RRC signaling, medium access control (Medium Access Control: MAC) signaling, broadcast information (Master Information Block: MIB, System Information Block: SIB)), other signals or a combination thereof. In addition, RRC signaling may also be referred to as an RRC message, for example, it may also be an RRC connection setup (RRC Connection Setup) message, an RRC connection reconfiguration (RRC Connection Reconfiguration) message, etc.

[0177] Each form / embodiment described in the present disclosure may also be applied to at least one of Long Term Evolution (LTE), LTE-Advanced (LTE-A), SUPER 3G, IMT-Advanced, 4th generation mobile communication system (4G), 5th generation mobile communication system (5G), Future Radio Access (FRA), New Radio (NR), W-CDMA (registered trademark), GSM (registered trademark), CDMA 2000, Ultra Mobile Broadband (UMB), IEEE 802.11 (Wi-Fi (registered trademark)), IEEE 802.16 (WiMAX (registered trademark)), IEEE 802.20, UWB (Ultra-WideBand), Bluetooth (registered trademark), a system using other appropriate systems, and a next-generation system extended therefrom. In addition, a combination of a plurality of systems (for example, a combination of at least one of LTE and LTE-A with 5G, etc.) may also be applied.

[0178] The processing procedures, timings, processes, etc. of each form / implementation described in this disclosure may be changed in order without contradiction. For example, for the method described in this disclosure, the elements of various steps are presented in an illustrative order, but are not limited to the specific order presented.

[0179] In the present disclosure, specific actions performed by a base station are sometimes performed by its upper node depending on the situation. In a network consisting of one or more network nodes having a base station, various actions performed to communicate with a terminal can be performed by at least one of the base station and other network nodes other than the base station (for example, consider MME or S-GW, etc., but not limited to these). In the above, the case where there is one other network node other than the base station is illustrated, but the other network node may also be a combination of multiple other network nodes (for example, MME and S-GW).

[0180] Information, signals (information, etc.) can be output from a higher layer (or lower layer) to a lower layer (or higher layer), and can also be input or output via multiple network nodes.

[0181] The input or output information can be stored in a specific location (e.g., memory) or managed using a management table. The input or output information can be rewritten, updated, or appended. The output information can also be deleted. The input information can also be sent to other devices.

[0182] The determination may be made by a value represented by one bit (0 or 1), by a Boolean value (Boolean: true or false), or by comparison of numerical values ​​(for example, comparison with a predetermined value).

[0183] Each form / implementation described in the present disclosure may be used alone or in combination, and may be switched depending on the execution. In addition, notification of scheduled information is not limited to being performed explicitly (e.g., notification of "yes X"), but may also be performed implicitly (e.g., notification of the scheduled information is not performed).

[0184] Software, whether referred to as software, firmware, middleware, microcode, hardware description language, or by other names, shall be interpreted broadly to refer to commands, sets of commands, codes, code segments, program codes, programs, subroutines, software modules, applications, software applications, software packages, routines, subroutines, objects, executable files, execution threads, procedures, functions, etc.

[0185] In addition, software, commands, information, etc. may be sent and received via a transmission medium. For example, when software is sent from a web page, server, or other remote source using at least one of wired technology (coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), etc.) and wireless technology (infrared, microwave, etc.), at least one of these wired technology and wireless technology is included in the definition of transmission medium.

[0186] The information, signals, etc. described in the present disclosure may also be represented by any of a variety of different technologies. For example, data, commands, instructions, information, signals, bits, symbols, chips, etc. that may be involved in the above description as a whole may be represented by voltage, current, electromagnetic waves, magnetic fields or magnetic particles, light fields or photons, or any combination thereof.

[0187] In addition, the terms described in the present disclosure and the terms required for understanding the present disclosure may be replaced with terms having the same or similar meanings. For example, at least one of a channel and a symbol may also be a signal (signaling). In addition, a signal may also be a message. In addition, a component carrier (CC) may be referred to as a carrier frequency, a cell, a frequency carrier, etc.

[0188] As used in this disclosure, the terms "system" and "network" may be used interchangeably.

[0189] In addition, the information, parameters, etc. described in the present disclosure may be represented by absolute values, relative values ​​to predetermined values, or other corresponding information. For example, wireless resources may also be indicated by indexes.

[0190] The names used for the above parameters are not limiting in any way. Furthermore, the formulas etc. using these parameters may sometimes differ from those explicitly disclosed in this disclosure. Various channels (e.g., PUCCH, PDCCH, etc.) and information elements may be identified by appropriate names, and therefore the various names assigned to these various channels and information elements are not limiting in any way.

[0191] In the present disclosure, the terms "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", "component carrier" and the like are used interchangeably. Base stations are sometimes referred to as macrocells, small cells, femtocells, picocells, etc.

[0192] A base station can accommodate one or more (for example, 3) cells (also called sectors). When a base station accommodates multiple cells, the overall coverage area of ​​the base station can be divided into multiple smaller areas, and each smaller area can also provide communication services through a base station subsystem (for example, a small base station for indoor use (Remote Radio Head: RRH).

[0193] The terms "cell" or "sector" refer to a part or the entirety of a coverage area of ​​at least one of a base station and a base station subsystem that provide communication services within the coverage area.

[0194] In the present disclosure, terms such as “mobile station (MS)”, “user terminal (user terminal)”, “user equipment (UE)”, and “terminal” may be used interchangeably.

[0195] For mobile stations, those skilled in the art sometimes also use the following terms: subscriber station, mobile unit, subscriber unit, wireless unit, remote unit, mobile device, wireless device, wireless communication device, remote device, mobile subscriber station, access terminal, mobile terminal, wireless terminal, remote terminal, handset, user agent, mobile client, client, or some other appropriate terms.

[0196] At least one of the base station and the mobile station may also be referred to as a transmitting device, a receiving device, a communication device, etc. In addition, at least one of the base station and the mobile station may be a device mounted on a mobile body, the mobile body itself, etc. The mobile body may be a means of transportation (e.g., a car, an airplane, etc.), a mobile body that moves in an unmanned manner (e.g., a drone, an autonomous vehicle, etc.), 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 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.

[0197] In addition, the base station in the present disclosure may also be replaced by a mobile station (user terminal, the same below). For example, regarding a structure in which the communication between a base station and a mobile station is replaced by communication between multiple mobile stations (for example, it may also be referred to as D2D (Device-to-Device), V2X (Vehicle-to-Everything, etc.), the various forms / implementations of the present disclosure may also be applied. In this case, it may also be a structure in which the mobile station has the functions of the base station. In addition, terms such as "uplink" and "downlink" may also be replaced by terms corresponding to communication between terminals (for example, "side"). For example, an uplink channel, a downlink channel, etc. may also be replaced by a side channel.

[0198] Likewise, the mobile station in the present disclosure may be replaced by a base station. In this case, the base station may have the same functions as the mobile station.

[0199] A radio frame may be composed of one or more frames in the time domain. In the time domain, one or more frames may be referred to as subframes.

[0200] A subframe may consist of one or more time slots in the time domain. A subframe may be a fixed time length (eg, 1 ms) that is independent of numerology.

[0201] A parameter set may be a communication parameter applied to at least one of the transmission and reception of a certain signal or channel. The parameter set may, for example, represent at least one of a subcarrier spacing (SCS), bandwidth, symbol length, cyclic prefix length, transmission time interval (TTI), number of symbols per TTI, wireless frame structure, specific filtering processing performed by a transceiver in the frequency domain, specific windowing processing performed by a transceiver in the time domain, and the like.

[0202] A slot may be composed of one or more symbols (Orthogonal Frequency Division Multiplexing (OFDM) symbols, Single Carrier Frequency Division Multiple Access (SC-FDMA) symbols, etc.) in the time domain. A slot may be a time unit based on a parameter set.

[0203] A time slot may contain multiple mini-slots. Each mini-slot may be composed of one or more symbols in the time domain. In addition, a mini-slot may also be referred to as a sub-slot. A mini-slot may be composed of fewer symbols than a time slot. A PDSCH (or PUSCH) transmitted in units of time greater than a mini-slot may be referred to as a PDSCH (or PUSCH) mapping type A. A PDSCH (or PUSCH) transmitted using a mini-slot may be referred to as a PDSCH (or PUSCH) mapping type B.

[0204] A radio frame, a subframe, a time slot, a mini-time slot, and a symbol all represent time units for transmitting signals. A radio frame, a subframe, a time slot, a mini-time slot, and a symbol may be referred to by other corresponding names.

[0205] For example, 1 subframe can be called a transmission time interval (TTI), multiple consecutive subframes can also be called a TTI, and 1 time slot or 1 mini time slot can also be called a TTI. That is, at least one of the subframe and the TTI can be a subframe (1ms) in the existing LTE, or a period shorter than 1ms (for example, 1-13 code elements), or a period longer than 1ms. In addition, the unit representing TTI can be a time slot, a mini time slot, etc. instead of a subframe.

[0206] Here, TTI refers to, for example, the minimum time unit for scheduling in wireless communication. For example, in the LTE system, the base station schedules the allocation of wireless resources (frequency bandwidth, transmission power, etc. that can be used in each user terminal) to each user terminal in units of TTI. In addition, the definition of TTI is not limited to this.

[0207] TTI can be a transmission time unit for data packets (transport blocks), code blocks, code words, etc. after channel coding, or a processing unit for scheduling, link adaptation, etc. In addition, when TTI is assigned, the time interval (e.g., the number of symbols) to which the transport block, code block, code word, etc. is actually mapped can be shorter than the TTI.

[0208] In addition, when 1 time slot or 1 mini time slot is called TTI, more than one TTI (ie, more than one time slot or more than one mini time slot) can constitute the minimum time unit of scheduling. In addition, the number of time slots (mini time slots) constituting the minimum time unit of scheduling can be controlled.

[0209] A TTI having a time length of 1 ms is also called a normal TTI (TTI in LTE Rel.8-12), a normal TTI, a long TTI, a normal subframe, a normal subframe, a long subframe, a time slot, etc. A TTI shorter than a normal TTI may be called a shortened TTI, a short TTI, a partial or fractional TTI, a shortened subframe, a short subframe, a mini-time slot, a sub-time slot, a time slot, etc.

[0210] In addition, for a long TTI (for example, a normal TTI, a subframe, etc.), it can be replaced with a TTI having a time length exceeding 1ms, and for a short TTI (for example, a shortened TTI, etc.), it can be replaced with a TTI length that is smaller than the long TTI (longTTI) and has a TTI length of more than 1ms.

[0211] A resource block (RB) is a resource allocation unit in the time domain and the frequency domain. In the frequency domain, it may contain one or more consecutive subcarriers. The number of subcarriers contained in an RB may be the same regardless of the parameter set, for example, it may be 12. The number of subcarriers contained in an RB may also be determined according to the parameter set.

[0212] In addition, the time domain of an RB may include one or more symbols, and may be the length of 1 slot, 1 mini slot, 1 subframe, or 1 TTI. 1 TTI, 1 subframe, etc. may be composed of one or more resource blocks, respectively.

[0213] In addition, one or more RBs may be referred to as a physical resource block (PRB), a sub-carrier group (SCG), a resource element group (REG), a PRB pair, an RB pair, and the like.

[0214] In addition, a resource block may be composed of one or more resource elements (RE). For example, 1 RE may be a radio resource region of 1 subcarrier and 1 symbol.

[0215] Bandwidth Part (BWP) (also called partial bandwidth, etc.) represents a subset of contiguous common RBs (common resource blocks) for a parameter set in a certain carrier. Here, the common RB can be determined by the index of the RB based on the common reference point of the carrier. PRBs are defined in a certain BWP and numbered within the BWP.

[0216] The BWP may include a BWP for UL (UL BWP) and a BWP for DL ​​(DL BWP). One or more BWPs may be configured for a UE within one carrier.

[0217] At least one of the set BWPs may be active, and it is not assumed that the UE transmits or receives a predetermined signal / channel outside the activated BWP. In addition, "cell", "carrier" and the like in the present disclosure may be replaced with "BWP".

[0218] The above structures of radio frames, subframes, time slots, mini-time slots, and symbols are only examples. For example, the number of subframes included in a radio frame, the number of time slots per subframe or radio frame, the number of mini-time slots included in a time slot, the number of symbols and RBs included in a time slot or mini-time slot, the number of subcarriers included in an RB, the number of symbols in a TTI, the symbol length, the cyclic prefix (CP: Cyclic Prefix) length, and the like can be changed in various ways.

[0219] The terms "connected", "coupled" or all variations of these terms are intended to indicate any direct or indirect connection or combination between two or more elements, and may include the situation where there is one or more intermediate elements between two elements that are "connected" or "coupled" to each other. The combination or connection between elements may be a physical combination or connection, a logical combination or connection, or a combination of these. For example, "access" may be used to replace "connection". In the context of the present disclosure, for two elements, it may be considered that they are "connected" or "coupled" to each other by using at least one of one or more wires, cables, and printed electrical connections, and as some non-limiting and non-inclusive examples, by using electromagnetic energy having wavelengths in the wireless frequency domain, microwave region, and light (including both visible and invisible) region, etc.

[0220] The reference signal may be referred to as Reference Signal (RS) for short, or may be referred to as a pilot signal depending on the applied standard.

[0221] The phrase "according to" used in the present disclosure does not mean "only according to" unless otherwise expressly stated. In other words, the phrase "according to" means both "only according to" and "at least according to".

[0222] Any reference to an element using the terms "first", "second", etc. used in this disclosure does not necessarily limit the number and order of these elements. These terms are used in this disclosure as a simple method to distinguish between two or more elements. Therefore, a reference to a first and a second element does not mean that only two elements can be used here or that the first element must precede the second element in any form.

[0223] When the terms "include," "including," and variations thereof are used in the present disclosure, these terms are intended to be inclusive, as is the term "comprising." Furthermore, the term "or" used in the present disclosure does not mean an exclusive or.

[0224] In the present disclosure, when an article is added by translation, such as a, an, and the in English, for example, the present disclosure also includes the case where the noun following the article is in plural form.

[0225] The terms "determining" and "determining" used in the present disclosure sometimes also include various actions. "Determining" and "determining" may include, for example, considering matters that have been judged, calculated, calculated, processed, derived, investigated, searched (for example, searched in a table, database or other data structure), confirmed (ascertaining) as matters that have been "judged" or "determined", etc. In addition, "determining" and "determining" may include considering matters that have been received (for example, receiving information), transmitted (for example, transmitting information), input, output, accessed (for example, accessed data in memory) as matters that have been "judged" or "determined", etc. In addition, "determining" and "determining" may include considering matters that have been resolved (resolving), selected (selecting), chosen (choosing), established (establishing), compared (comparing), etc. as matters that have been "judged" or "determined". That is, "determining" and "determining" may include matters that have been "judged" or "determined" by any action. In addition, the word “determine” can also be replaced by “assuming”, “expecting”, “considering”, etc.

[0226] In the present disclosure, the phrase "A and B are different" may also mean "A and B are different from each other". In addition, the phrase may also mean "A and B are different from C, respectively". The phrases such as "separate" and "combine" may also be interpreted as "different".

[0227] The present disclosure is described in detail above, but it should be clear to those skilled in the art that the present disclosure is not limited to the embodiments described in the present disclosure. The present disclosure can be implemented as a modification and variation without departing from the subject matter and scope of the present disclosure as determined by the claims. Therefore, the purpose of the description of the present disclosure is to illustrate and not to have any limiting meaning on the present disclosure.

[0228] Description of labels:

[0229] 10.10a Wireless Communication System

[0230] 100A, 100B, 100C, 110A, 110B, 110C, 110D gNB

[0231] 200 Terminal

[0232] 210 Sending Department

[0233] 220 Receiving Department

[0234] 230 Holding Unit

[0235] 250 Control Department

[0236] 1001 Processor

[0237] 1002 Memory

[0238] 1003 Memory

[0239] 1004 Communication device

[0240] 1005 Input Device

[0241] 1006 Output Device

[0242] 1007 Bus

Claims

1. A terminal, wherein: The terminal has: a receiving unit that receives, in a conditional handover procedure (CHO procedure), a first RRC reconfiguration including CHO setting information from a relocation source cell, the CHO setting information including information of a relocation destination cell and a relocation condition; as well as a control unit that performs relocation to the relocation destination cell without receiving a relocation command based on the CHO setting information, The receiving unit receives, during the CHO process, a second RRC reconfiguration including change information for the CHO setting information, When the change information indicates that the relocation condition has been updated, the control unit updates the relocation condition based on the change information and does not update the information of the relocation destination cell.

2. A wireless communication system having a terminal and a wireless base station, wherein: The terminal has: a receiving unit configured to receive, in a conditional handover procedure (CHO procedure), from the radio base station a first RRC reconfiguration including CHO setting information, the CHO setting information including information of a relocation destination cell and a relocation condition; as well as a control unit that performs relocation to the relocation destination cell without receiving a relocation command based on the CHO setting information, The receiving unit receives, during the CHO process, a second RRC reconfiguration including change information for the CHO setting information from the wireless base station, When the change information indicates that the relocation condition has been updated, the control unit updates the relocation condition based on the change information and does not update the information of the relocation destination cell.

3. A wireless communication method applicable to a terminal, wherein: The wireless communication method comprises the following steps: The terminal receives a first RRC reconfiguration including CHO setting information from a relocation source cell in a conditional handover process, namely, a CHO process, wherein the CHO setting information includes information of a relocation destination cell and a relocation condition; The terminal receives, during the CHO process, a second RRC reconfiguration including change information for the CHO setting information; When the change information indicates that the migration condition has been updated, the terminal updates the migration condition based on the change information and does not update the information of the migration destination cell; as well as The terminal performs relocation to the relocation destination cell without receiving a relocation command based on the CHO setting information.

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