Terminal, base station, and communication method

Abstract

This terminal comprises: a reception unit that receives a downlink control channel from a first base station; and a transmission unit that transmits, to a second base station, a random access channel without a random access response in contention-free random access indicated by the downlink control channel. The reception unit receives, from the first base station, a message including timing advance information. The terminal further comprises a control unit that enables monitoring of a condition for executing cell switching to the second base station, and if the condition is satisfied, uses the timing advance information to execute configuration for the cell switching.

Description

Terminal, Base Station, and Communication Method

[0007] ,

[0006] ,

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

[0002] In 3GPP (Registered Trademark) (3rd Generation Partnership Project), in order to achieve further increase in system capacity, further increase in data transmission speed, further reduction in latency in the radio section, etc., a wireless communication method called 5G or NR (New Radio) (hereinafter, this wireless communication method is referred to as "NR") is being studied. In 5G, in order to meet the requirement of achieving a throughput of 10 Gbps or more while reducing the latency in the radio section to 1 ms or less, various wireless technologies and network architectures are being studied (for example, Non-Patent Document 1 and Non-Patent Document 2).

[0003] Also, in 3GPP Rel-18, regarding a base station including a CU (Central Unit) and a DU (Distributed Unit), Intra-CU Lower-Layer Triggered Mobility of a network trigger is supported. In Rel-19, Inter CU Lower-Layer Triggered Mobility of a network trigger is planned to be supported.

[0004] 3GPP TS 38.300 V18.2.0 (2024-06) 3GPP TS 38.401 V18.3.0 (2024-09) 3GPP TS 38.321 V18.2.0 (2024-06)

[0005] In 3GPP Rel-19, in addition to the LTM of a network trigger, Conditional LTM of a terminal trigger is planned to be supported, but the procedure regarding the LTM of a terminal trigger is not defined.

[0006] The present invention has been made in view of the above points, and an object thereof is to define a procedure regarding the LTM of a terminal trigger in a wireless communication system.

[0007] According to the disclosed technology, a terminal is provided which includes a receiving unit that receives a downlink control channel from a first base station, and a transmitting unit that transmits a random access channel without random access response in a no-contour random access, as instructed in the downlink control channel, to a second base station, wherein the receiving unit receives a message including timing advance information from the first base station, enables monitoring of the conditions for performing cell switching to the second base station, and, if the conditions are met, uses the timing advance information to perform the settings for the cell switching.

[0008] According to the disclosed technology, procedures relating to the terminal trigger LTM can be defined in a wireless communication system.

[0009] This is a diagram illustrating a wireless communication system in an embodiment of the present invention. This is a diagram illustrating a wireless communication system in an embodiment of the present invention. This is an example of a sequence diagram relating to Embodiment 1 in an embodiment of the present invention. This is an example of a sequence diagram relating to Embodiment 2 in an embodiment of the present invention. This is an example of a sequence diagram relating to Embodiment 3 in an embodiment of the present invention. This is a diagram illustrating the LTM cell switch command MAC CE in an embodiment of the present invention. This is a diagram illustrating the TA information transfer command MAC CE in an embodiment of the present invention. This is a diagram illustrating an example of the functional configuration of the base station 10 in an embodiment of the present invention. This is a diagram illustrating an example of the functional configuration of the terminal 20 in an embodiment of the present invention. This is a diagram illustrating an example of the hardware configuration of the base station 10 or terminal 20 in an embodiment of the present invention. This is a diagram illustrating an example of the configuration of the vehicle 2001 in an embodiment of the present invention.

[0010] Embodiments of the present invention will be described below with reference to the drawings. Note that the embodiments described below are examples, and the embodiments to which the present invention is applied are not limited to those described below.

[0011] In the operation of the wireless communication system according to the embodiments of the present invention, existing technologies may be used as appropriate. However, such existing technologies include, for example, existing LTE, but are not limited to existing LTE. Furthermore, the term "LTE" as used herein has a broad meaning that includes LTE-Advanced and LTE-Advanced and later technologies (e.g., NR), unless otherwise specified.

[0012] Furthermore, in the embodiments of the present invention described below, terms such as SS (Synchronization signal), PSS (Primary SS), SSS (Secondary SS), PBCH (Physical broadcast channel), PRACH (Physical random access channel), PDCCH (Physical Downlink Control Channel), PDSCH (Physical Downlink Shared Channel), PUCCH (Physical Uplink Control Channel), and PUSCH (Physical Uplink Shared Channel), which are used in existing LTE technologies, will be used. This is for convenience of description, and similar signals, functions, etc., may be called by other names. In NR, the above terms will be referred to as SS, PSS, SSS, PBCH, PRACH, etc., without any particular distinction from LTE.

[0013] Furthermore, in the embodiments of the present invention, the duplex system may be a TDD (Time Division Duplex) system, an FDD (Frequency Division Duplex) system, or any other system (for example, a Flexible Duplex).

[0014] Furthermore, in the embodiments of the present invention, "configuring" wireless parameters may mean that predetermined values ​​are pre-configured, or that wireless parameters notified from the base station 10 or terminal 20 are configured.

[0015] Figure 1 shows an example of the configuration of a wireless communication system in an embodiment of the present invention. The wireless communication system in the embodiment of the present invention includes a base station 10 and a terminal 20, as shown in Figure 1. Figure 1 shows one base station 10 and one terminal 20, but this is an example, and there may be multiple base stations 10 and terminals 20.

[0016] Base station 10 is a communication device that provides one or more cells and communicates wirelessly with terminal 20. The physical resources of the wireless signal are defined in the time domain and the frequency domain. The time domain may be defined by the number of OFDM (Orthogonal Frequency Division Multiplexing) symbols, and the frequency domain may be defined by the number of subcarriers or resource blocks. Base station 10 transmits synchronization signals and system information to terminal 20. Synchronization signals are, for example, PSS and SSS. System information is transmitted, for example, via PBCH or PDSCH, and is also called broadcast information. Synchronization signals and system information may be called SSB (SS / PBCH block). As shown in Figure 1, base station 10 transmits control signals or data to terminal 20 via DL (Downlink) and receives control signals or data from terminal 20 via UL (Uplink). Both base station 10 and terminal 20 are capable of transmitting and receiving signals using beamforming. Furthermore, both the base station 10 and the terminal 20 can apply MIMO (Multiple Input Multiple Output) communication to DL or UL. Also, both the base station 10 and the terminal 20 may communicate via Carrier Aggregation (CA) through secondary cells (SCell) and primary cells (PCell). Additionally, the terminal 20 may communicate via Dual Connectivity (DC) through the primary cell of base station 10 and the primary secondary cell group cell (PSCell) of another base station 10.

[0017] Terminal 20 is a communication device equipped with wireless communication capabilities, such as a smartphone, mobile phone, tablet, wearable device, or M2M (Machine-to-Machine) communication module. As shown in Figure 1, Terminal 20 receives control signals or data from the base station 10 via DL and transmits control signals or data to the base station 10 via UL, thereby utilizing various communication services provided by the wireless communication system. Terminal 20 also receives various reference signals transmitted from the base station 10 and performs propagation path quality measurement based on the reception results of said reference signals.

[0018] Figure 2 is a diagram illustrating a wireless communication system according to an embodiment of the present invention. Figure 2 shows an example configuration of a wireless communication system when DC (Dual connectivity) is performed. As shown in Figure 2, a base station 10A, which will be an MN (Master Node), and a base station 10B, which will be an SN (Secondary Node), are provided. Base stations 10A and 10B are each connected to the core network. Terminal 20 can communicate with both base station 10A and base station 10B.

[0019] A cell group provided by base station 10A, which is an MN (Mobile Network), is called an MCG (Master Cell Group), and a cell group provided by base station 10B, which is an SN (Mobile Network), is called an SCG (Secondary Cell Group). In a data center, an MCG consists of one PCell and one or more SCells, and an SCG consists of one PSCell (Primary SCG Cell) and one or more SCells.

[0020] The processing operations in this embodiment may be performed using the system configuration shown in Figure 1, the system configuration shown in Figure 2, or any other system configuration. In the following description, " / " means "and / or" unless otherwise specified, or unless it is clear from the context that it has a different meaning.

[0021] Base station 10 includes a CU (Central Unit) and a DU (Distributed Unit). In Lower-Layer Triggered Mobility (LTM), the source CU and DU are referred to as the source CU and source DU, and the candidate CU and DU for the destination during handover are referred to as the candidate CU and candidate DU.

[0022] In a wireless communication system, the following method may be used to define the procedure for terminal triggering LTM (Lower-Layer Triggered Mobility).

[0023] (Method 1) In the terminal trigger's CU-internal LTM (Conditional intra-CU LTM), the source DU may obtain the TA value in the candidate cell by transferring TA information (Timing Advance information) from the candidate DU, and then notify the terminal 20 of the said TA value.

[0024] (Method 2) In a terminal-triggered inter-CU LTM (Conditional inter-CU LTM), the source DU may obtain the TA value in the candidate cell by transferring TA information (Timing Advance information) from the candidate base station 10, and then notify the terminal 20 of the TA value.

[0025] (Method 3) In Methods 1 and 2, the signaling for notifying the TA value may be a newly defined signaling (e.g., MAC (Medium Access Control) CE (Control Element)), or an existing signaling (e.g., LTM cell switch command) may be reused.

[0026] (Method 4) When an LTM cell switch command is reused as a signaling for notifying the TA value, and when network-triggered LTMs and terminal-triggered LTMs are used together, a bit that is not used in the existing LTM cell switch command (Reserved bit) may be used as information to indicate whether it is a network-triggered LTM or a terminal-triggered LTM TA information transfer command.

[0027] (Method 5) In a terminal-triggered LTM (Conditional LTM), terminal 20 may store the TA of candidate cells notified from the network (base station 10) in its own device. Terminal 20 may also store the TA of multiple candidate cells in its own device simultaneously.

[0028] (Method 6) In a terminal-triggered LTM (Conditional LTM), if terminal 20 holds the TA of a candidate cell to be switched that satisfies the execution condition, it may use the TA value to perform an LTM cell switch without performing a random access procedure (RACH less).

[0029] (Method 7) In the terminal trigger LTM (Conditional LTM), when terminal 20 receives a message to transmit TA information (TA information transfer command), it may activate the execution condition for executing cell switching to the candidate cell corresponding to the TA. Alternatively, this activation may be the activation of monitoring of the execution condition for executing cell switching to the candidate cell.

[0030] The following describes some examples.

[0031] (Example 1) Example 1 describes the procedure for terminal trigger CU in-LTM (Conditional intra-CU Lower-Layer Triggered Mobility). Figure 3 is an example of a sequence diagram according to Example 1 in the embodiment of the present invention. The processing of each step will be described below.

[0032] S101: Terminal 20 sends an L3 measurement report to source CU10B.

[0033] S102: Processing related to LTM preparation (LTM preparation) is performed between source CU10B and candidate DU10C.

[0034] S103: Source CU10B sends a message to terminal 20 containing information related to an RRC reconfiguration request. The message also includes conditions regarding whether the conditions for performing cell switching are met. These conditions include, for example, whether the signal strength from the destination base station (candidate DU10C) exceeds a predetermined threshold compared to the signal strength from the source base station (source DU10A).

[0035] S104: Terminal 20 sends a message to source CU10B notifying it that the RRC reconfiguration is complete.

[0036] S105: Early DL / UL sync processing is performed between terminal 20, source DU10A, source CU10B, and candidate DU10C for initial downlink synchronization and initial uplink synchronization of the downlink and uplink. Here, terminal 20 may acquire information regarding Timing Advance (TA) during the initial uplink synchronization processing.

[0037] S106: Terminal 20 activates the monitoring of the execution condition, which was received in S103, regarding whether the conditions for performing cell switching are met.

[0038] Alternatively, after receiving the RRC reconfiguration in S103, the monitoring may be enabled. Or, under the condition that the terminal 20 does not need to obtain information regarding the TA (i.e., the terminal 20 executes a random access (RACH) procedure to obtain the information), the terminal 20 may enable the monitoring after S103 or S104.

[0039] S107: If the monitoring execution condition in S106 is satisfied, the terminal 20 determines to execute the LTM cell switch.

[0040] S108: To execute the cell switch, the terminal 20 applies the setting of the target candidate DU10C of the destination. The setting may include the information regarding the TA received in S105.

[0041] S109: For example, if the process of S105 is not executed, the terminal 20 executes a random access procedure with the candidate DU10C and receives a RAR (Random Access Response) including the information regarding the TA from the candidate DU10.

[0042] S110: The process to complete the LTM is executed, and the handover from the source CU10B to the candidate DU10C is completed.

[0043] (Embodiment 2) In Embodiment 2, a procedure regarding conditional intra-CU lower-layer triggered mobility (LTM) triggered by a terminal will be described. FIG. 4 is an example of a sequence diagram according to Embodiment 2 in the embodiment of the present invention. Hereinafter, the processing of each step will be described.

[0044] S201: The terminal 20 transmits an L3 measurement report to the source CU10B.

[0045] S202: The processing regarding the preparation of the LTM (LTM preparation) is executed among the source CU10B, the candidate CU10D, and the candidate DU10C.

[0046] S203: The source CU10B transmits a message including information related to an RRC reconfiguration request to the terminal 20. Further, the message includes conditions related to execution conditions regarding whether the conditions for performing cell switching are satisfied. The conditions are, for example, conditions as to whether the signal strength from the target base station (candidate DU10C) exceeds a predetermined threshold value more than the signal strength from the source base station (source DU10A).

[0047] S204: The terminal 20 transmits a message (RRC reconfiguration complete) notifying the source CU10B of the completion of RRC reconfiguration.

[0048] S205: Early DL / UL sync of the downlink and uplink is performed among the terminal 20, the source DU10A, the source CU10B, the candidate CU10D, and the candidate DU10C. Here, the terminal 20 may obtain information regarding Timing Advance (TA) in the process of initial uplink synchronization.

[0049] S206: The terminal 20 activates the monitoring (Monitor execution condition) of the execution conditions regarding whether the conditions for performing cell switching received in S203 are satisfied.

[0050] Alternatively, the monitoring may be activated after receiving the RRC reconfiguration in S203. Or, in the conditions, if the terminal 20 does not need to obtain information regarding TA (that is, the terminal 20 executes a random access (RACH) procedure to obtain the information), the terminal 20 may activate the monitoring after S203 or S204.

[0051] S207: If the monitoring execution conditions in S206 are satisfied, the terminal 20 determines to execute LTM cell switching.

[0052] S208: Terminal 20 applies the settings of the target candidate CU10D and candidate DU10C, which are the destinations, in order to perform cell switching. These settings may include information about the TA received in S205.

[0053] S209: If, for example, the process in S205 is not executed, terminal 20 performs a random access procedure between candidate CU10D and candidate DU10C and receives a Random Access Response (RAR) containing information about TA from candidate DU10.

[0054] S210: The process to complete LTM is executed, and the handover from source DU10A and source CU10B to candidate DU10C and candidate CU10D is completed.

[0055] (Example 3) Example 3 describes the procedure for early acquisition of timing advance for terminal trigger LTM (early TA acquisition for Conditional LTM). In this procedure, terminal 20 transmits a random access channel without a random access response (PDCCH ordered RACH (Random Access Channel) without RAR (Random Access Response)) in Contention Free Random Access (CFRA) to candidate DU 10C. This procedure is executed as part of the Early UL sync process at S105 and S205 in the sequence diagrams described in Figures 3 and 4.

[0056] Figure 5 is an example of a sequence diagram according to Embodiment 3 of the present invention. The processing of each step will be described below.

[0057] S301: Source DU10A transmits a downlink control channel (PDCCH) signal to terminal 20. The signal includes a random access index (RA preamble index), an uplink / auxiliary uplink indicator (UL / SUL indicator), a synchronous signal block index (SSB index), information about available random access opportunities (PRACH Mask index), a cell indicator, a PRACH association indicator, and a PRACH retransmission indicator.

[0058] S302: Based on the instructions received in S301 via the downlink control channel (PDCCH), terminal 20 transmits a random access channel without a random access response (PDCCH ordered RACH) in a non-conflict random access (CFRA) to candidate DU10C.

[0059] S303: Candidate DU10C obtains a Timing Advance (TA) based on the information received in S302.

[0060] S304: Candidate DU10C sends a message to source CU10B indicating that TA information will be sent from DU to CU (DU-CU TA information transfer).

[0061] S305: Source CU10B sends a message to source DU10A indicating that TA information is to be transferred from CU to DU (CU-DU TA information transfer).

[0062] S306: Source DU10A sends a message to terminal 20 that transmits TA information (TA information transfer command). As this message, for example, the LTM cell switch command MAC CE from the existing specification (see section 6.1.3.75 of Non-Patent Literature 3) may be reused. Figure 6 is a diagram illustrating the LTM cell switch command MAC CE in an embodiment of the present invention. As shown in Figure 6, the first two octets (Oct 1 and Oct 2) contain bits indicating C, Target Config ID, and Timing Advance Command as defined in the existing specification. If C is set to a value of 1, it indicates that it is a message for CFRA, and in the following fields, the RA Preamble index, S / U, SSB index, PRACH Mask index, Repetition number, and Reserved bit (R) are set. The Target Config ID is set to a value obtained by subtracting 1 from the value of the LTM candidate identifier (ltm-CandidateId). The Timing Advance Command contains information regarding timing advance. Here, for example, a new bit called Cond is defined in the third octet from the beginning, which is a bit not used in the existing specification (Reserved bit). If Cond is set to a value of 0, it indicates that it is a message for network-triggered LTM, and if it is set to a value of 1, it indicates that it is a message for terminal-triggered LTM (conditional LTM). In other words, Cond is information to distinguish whether a message is for network-triggered LTM or terminal-triggered LTM (conditional LTM). Therefore, in S306 of Figure 5, by sending an LTM cell switch command with Cond set to 1, source DU10A can send TA information to terminal 20.

[0063] Alternatively, in S306 of Figure 5, a new message may be defined for transmitting TA information from source DU10A to terminal 20. Figure 7 is a diagram illustrating the TA information transfer command MAC CE in an embodiment of the present invention. As shown in Figure 7, the first two octets (Oct 1 and Oct 2) contain bits indicating A, Target Config ID, and Timing Advance Command. The Target Config ID and Timing Advance Command are the same information as described in Figure 6. A is set to 0 when instructing activation of the execution condition in S106 and S206 of Figures 3 and 4 for the base station 10 (candidate DU10C / candidate CU10D), which is a candidate destination indicated by the Target Config ID, and to 1 when instructing deactivation.

[0064] (Effects) In the above embodiment, if a random access channel without a random access response (PDCCH ordered RACH without RAR) instructed by the downlink control channel is supported in the terminal trigger LTM (conditional LTM), the source DU can notify the terminal of the TA value of the candidate cell. In other words, a procedure for the terminal trigger LTM can be defined in the wireless communication system. As a result, by realizing a terminal trigger LTM (conditional LTM) without a random access procedure (RACH-less), network optimization and an improvement in the quality of service experienced by the user can be expected.

[0065] (Device Configuration) Next, an example of the functional configuration of the base station 10 and terminal 20 that perform the processes and operations described above will be explained. The base station 10 and terminal 20 include the functions to carry out the above-described embodiment. However, the base station 10 and terminal 20 may each be equipped with only some of the functions in the embodiment.

[0066] <Base Station 10> Figure 8 is a diagram showing an example of the functional configuration of a base station 10 in an embodiment of the present invention. As shown in Figure 8, the base station 10 has a transmitting unit 110, a receiving unit 120, a setting unit 130, and a control unit 140. The functional configuration shown in Figure 8 is merely an example. Any functional classification and functional unit names are acceptable as long as they can perform the operations according to the embodiment of the present invention.

[0067] The transmitting unit 110 includes the function of generating a signal to be transmitted to the terminal 20 and transmitting the signal wirelessly. The transmitting unit 110 also transmits setting information, instructions, and notifications to the terminal 20. The receiving unit 120 includes the function of receiving various signals transmitted from the terminal 20 and obtaining information from the received signals, for example, higher layer information. The transmitting unit 110 also has the function of transmitting PSS, SSS, PBCH, DL / UL control signals, etc. to the terminal 20. The receiving unit 120 also receives inter-network node messages from other network nodes.

[0068] The setting unit 130 stores pre-configured setting information and various setting information to be transmitted to the terminal 20.

[0069] The control unit 140 performs control related to setting, instructing, and notifying, as described in the embodiment. The signal transmission function unit of the control unit 140 may be included in the transmission unit 110, and the signal reception function unit of the control unit 140 may be included in the reception unit 120.

[0070] Furthermore, the CU and DU at the base station 10 may each have a transmitting unit 110, a receiving unit 120, a setting unit 130, and a control unit 140, and information may be transmitted and received between the CU and the DU.

[0071] <Terminal 20> Figure 9 is a diagram showing an example of the functional configuration of terminal 20 in an embodiment of the present invention. As shown in Figure 9, terminal 20 has a transmitting unit 210, a receiving unit 220, a setting unit 230, and a control unit 240. The functional configuration shown in Figure 9 is merely an example. Any functional classification and functional unit names are acceptable as long as they can perform the operations according to the embodiment of the present invention. The transmitting unit 210 and the receiving unit 220 may be collectively referred to as the communication unit.

[0072] The transmitting unit 210 creates a transmission signal from the transmission data and transmits the transmission signal wirelessly. The receiving unit 220 wirelessly receives various signals and obtains signals from higher layers from the received physical layer signals. The receiving unit 220 also has the function of receiving PSS, SSS, PBCH, DL / UL / SL control signals, etc. transmitted from the base station 10. The setting unit 230 stores various setting information received from the base station 10 by the receiving unit 220. The setting unit 230 also stores pre-set setting information.

[0073] The control unit 240 performs control related to setting, instructing, and notifying, as described in the embodiment. The signal transmission function in the control unit 240 may be included in the transmission unit 210, and the signal reception function in the control unit 240 may be included in the reception unit 220.

[0074] (Hardware Configuration) The block diagrams (Figures 8 and 9) 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 be realized by combining the above one device or the above multiple devices with software.

[0075] 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.

[0076] For example, the base station 10, terminal 20, etc. in one embodiment of the present disclosure may function as a computer that processes the wireless communication method of the present disclosure. Figure 10 is a diagram showing an example of the hardware configuration of the base station 10 and terminal 20 according to one embodiment of the present disclosure. The above-mentioned base station 10 and terminal 20 may be physically configured as a computer device including a processor 1001, a storage device 1002, an auxiliary storage device 1003, a communication device 1004, an input device 1005, an output device 1006, a bus 1007, etc.

[0077] In the following explanation, the term "device" can be read as "circuit," "device," "unit," etc. The hardware configuration of the base station 10 and terminal 20 may include one or more of the devices shown in the figure, or it may be configured without some of the devices.

[0078] Each function in the base station 10 and terminal 20 is realized by loading predetermined software (programs) onto hardware such as the processor 1001 and storage device 1002, which allows the processor 1001 to perform calculations, control communication by the communication device 1004, and control at least one of data reading and writing in the storage device 1002 and auxiliary storage device 1003.

[0079] 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 devices, arithmetic units, registers, etc. For example, the control unit 140, control unit 240, etc., described above may be implemented by the processor 1001.

[0080] Furthermore, the processor 1001 reads programs (program code), software modules, or data from at least one of the auxiliary storage device 1003 and the communication device 1004 into the storage device 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. For example, the control unit 140 of the base station 10 shown in Figure 8 may be implemented by a control program stored in the storage device 1002 and operated by the processor 1001. Also, for example, the control unit 240 of the terminal 20 shown in Figure 9 may be implemented by a control program stored in the storage device 1002 and operated by the processor 1001. Although the above-described processes have been explained as being 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 the network via a telecommunications line.

[0081] The storage device 1002 is a computer-readable recording medium and may consist of at least one of the following: ROM (Read Only Memory), EPROM (Erasable Programmable ROM), EEPROM (Electrically Erasable Programmable ROM), RAM (Random Access Memory), etc. The storage device 1002 may also be called a register, cache, main memory, etc. The storage device 1002 can store executable programs (program code), software modules, etc., for implementing a communication method according to one embodiment of the present disclosure.

[0082] The auxiliary storage device 1003 is a computer-readable recording medium and may consist of at least one of the following: an optical disc such as a CD-ROM (Compact Disc ROM), a hard disk drive, a flexible disk, a magneto-optical disk (e.g., a compact disk, a digital multipurpose disk, a Blu-ray® disk), a smart card, flash memory (e.g., a card, a stick, a key drive), a floppy® disk, a magnetic strip, etc. The above-mentioned storage medium may also be a database, server, or other suitable medium that includes at least one of the storage device 1002 and the auxiliary storage device 1003.

[0083] The communication device 1004 is hardware (transmitting / receiving 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). For example, the transmitting and receiving antenna, amplifier section, transmitting and receiving section, transmission path interface, etc., may be implemented by the communication device 1004. The transmitting and receiving section may be implemented in a physically or logically separated manner, with a transmitting section and a receiving section.

[0084] 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).

[0085] Furthermore, each device, such as the processor 1001 and the storage device 1002, is connected by a bus 1007 for communicating information. The bus 1007 may be configured using a single bus, or different buses may be configured for each device.

[0086] Furthermore, the base station 10 and terminal 20 may be configured to include hardware such as a microprocessor, a digital signal processor (DSP), an ASIC (Application Specific Integrated Circuit), a PLD (Programmable Logic Device), and an FPGA (Field Programmable Gate Array), 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.

[0087] Figure 11 shows an example of the configuration of vehicle 2001. As shown in Figure 11, vehicle 2001 includes a drive unit 2002, a steering unit 2003, an accelerator pedal 2004, a brake pedal 2005, a shift lever 2006, front wheels 2007, 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. Each aspect / embodiment described in this disclosure may be applied to a communication device mounted on vehicle 2001, for example, to the communication module 2013.

[0088] The drive unit 2002 consists of, for example, an engine, a motor, or a hybrid of an engine and a motor. 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.

[0089] 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 2029 installed in the vehicle 2001 are input to the electronic control unit 2010. The electronic control unit 2010 may also be called an ECU (Electronic Control Unit).

[0090] Signals from various sensors 2021 to 2029 include current signals from current sensor 2021 for sensing motor current, front or rear wheel rotation speed signals acquired by rotation speed sensor 2022, front or rear wheel air pressure signals acquired by air pressure sensor 2023, vehicle speed signals acquired by vehicle speed sensor 2024, acceleration signals acquired by acceleration sensor 2025, accelerator pedal depression signals acquired by accelerator pedal sensor 2029, brake pedal depression signals acquired by brake pedal sensor 2026, shift lever operation signals acquired by shift lever sensor 2027, and detection signals acquired by object detection sensor 2028 for detecting obstacles, vehicles, pedestrians, etc.

[0091] The Information Service Unit 2012 consists of various devices for providing (outputting) various types of information such as driving information, traffic information, and entertainment information, including a car navigation system, audio system, speakers, television, and radio, and one or more ECUs that control these devices. The Information Service Unit 2012 uses information acquired from external devices via a communication module 2013, etc., to provide various multimedia information and multimedia services to the occupants of the vehicle 2001. The Information Service Unit 2012 may include input devices that accept input from the outside (e.g., keyboard, mouse, microphone, switch, button, sensor, touch panel, etc.) and output devices that perform output to the outside (e.g., display, speaker, LED lamp, touch panel, etc.).

[0092] 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, LiDAR (Light Detection and Ranging), cameras, positioning locators (e.g., GNSS), map information (e.g., high-definition (HD) maps, autonomous vehicle (AV) maps), gyro systems (e.g., IMU (Inertial Measurement Unit), INS (Inertial Navigation System)), AI (Artificial Intelligence) chips, and AI processors, as well as one or more ECUs that control these devices. The driver assistance system unit 2030 also transmits and receives various information via the communication module 2013 to realize driver assistance functions or autonomous driving functions.

[0093] 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, front wheels 2007, rear wheels 2008, axle 2009, the microprocessor 2031 and memory (ROM, RAM) 2032 in the electronic control unit 2010, and sensors 2021-29 provided in the vehicle 2001.

[0094] 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 with 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.

[0095] The communication module 2013 may transmit at least one of the following to an external device via wireless communication: signals from the various sensors 2021-2028 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 2021-2028, 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 the information based on the above input.

[0096] The communication module 2013 receives various information (traffic information, signal information, inter-vehicle information, etc.) transmitted from an external device and displays it on the information service unit 2012 provided in the vehicle 2001. The information service unit 2012 may also be called an output unit, which outputs information (for example, 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). The communication module 2013 also stores the various information received from the external device in a memory 2032 that can be used by the microprocessor 2031. Based on the information stored in the memory 2032, the microprocessor 2031 may control the drive unit 2002, steering unit 2003, accelerator pedal 2004, brake pedal 2005, shift lever 2006, front wheels 2007, rear wheels 2008, axles 2009, sensors 2021-2029, etc., provided in the vehicle 2001.

[0097] <Configuration relating to this embodiment> (1) A terminal comprising: a receiving unit that receives a downlink control channel from a first base station; and a transmitting unit that transmits a random access channel without random access response in a no-contradiction random access instructed by the downlink control channel to a second base station, wherein the receiving unit further comprises a control unit that receives a message containing timing advance information from the first base station, enables monitoring of the conditions for performing cell switching to the second base station, and, if the conditions are met, uses the timing advance information to perform the settings for the cell switching. (2) The terminal according to paragraph 1, wherein the message is a newly defined first message or a second message that reuses a message of an existing specification, and the second message includes information for distinguishing between a network trigger LTM (Lower-Layer Triggered Mobility) and a terminal trigger LTM. (3) The terminal according to paragraph 1, wherein the receiving unit receives messages containing timing advance information from multiple base stations, and the control unit stores multiple timing advance information received from the multiple base stations in its own device. (4) The terminal according to paragraph 1, wherein the control unit uses the timing advance information to perform cell switching by LTM without performing a random access procedure. (5) A base station, comprising: a transmitting unit that transmits a downlink control channel to the terminal instructing it to transmit a random access channel without a random access response in a no-contradiction random access; a receiving unit that receives a first message containing timing advance information from another base station that received the random access channel; and the transmitting unit that transmits a second message containing the timing advance information to the terminal.(Clause 6) A communication method performed by a terminal comprising: receiving a downlink control channel from a first base station; transmitting a random access channel to a second base station, which is a random access channel without random access response in a no-contour random access environment as instructed in the downlink control channel; receiving a message containing timing advance information from the first base station; and enabling monitoring of the conditions for performing cell switching to the second base station, and if the conditions are met, using the timing advance information to perform the settings for the cell switching.

[0098] Any of the above configurations can define the procedure for the terminal trigger LTM in a wireless communication system.

[0099] (Supplement to Embodiments) Embodiments of the present invention have been described above, but the disclosed invention is not limited to such embodiments, and those skilled in the art will understand various modifications, alterations, alternatives, substitutions, etc. Specific numerical examples have been used to facilitate understanding of the invention, but unless otherwise specified, these numerical values ​​are merely examples, and any appropriate values ​​may be used. The division of items in the above description is not essential to the present invention, and matters described in two or more items may be combined as needed, and matters described in one item may be applied to matters described in another item (as long as they do not contradict each other). The boundaries of functional units or processing units in the functional block diagram do not necessarily correspond to the boundaries of physical parts. The operation of multiple functional units may be physically performed by one part, or the operation of one functional unit may be physically performed by multiple parts. The processing procedures described in the embodiments may be rearranged as long as they do not contradict each other. For the convenience of explaining the processing, the base station 10 and terminal 20 have been described using functional block diagrams, but such devices may be realized in hardware, software, or a combination thereof. The software operated by the processor of the base station 10 according to an embodiment of the present invention and the software operated by the processor of the terminal 20 according to an embodiment of the present invention may be stored in random access memory (RAM), flash memory, read-only memory (ROM), EPROM, EEPROM, register, hard disk (HDD), removable disk, CD-ROM, database, server, or any other suitable storage medium, and the notification of information may be performed by other methods, not limited to the embodiments / models described herein.For example, information notification may be carried out by physical layer signaling (e.g., DCI (Downlink Control Information), UCI (Uplink Control Information)), higher layer signaling (e.g., RRC (Radio Resource Control) signaling, MAC (Medium Access Control) signaling), broadcast information (MIB (Master Information Block), SIB (System Information Block)), other signals, or combinations thereof. RRC signaling may also be called RRC messages, for example, RRC Connection Setup messages, RRC Connection Reconfiguration messages, etc.

[0100] Each aspect / embodiment described in this disclosure may be applied to at least one of the following systems: LTE (Long Term Evolution), LTE-A (LTE-Advanced), SUPER 3G, IMT-Advanced, 4G (4th generation mobile communication system), 5G (5th generation mobile communication system), FRA (Future Radio Access), NR (new Radio), W-CDMA®, GSM®, CDMA2000, UMB (Ultra Mobile Broadband), IEEE 802.11 (Wi-Fi®), IEEE 802.16 (WiMAX®), IEEE 802.20, UWB (Ultra-WideBand), Bluetooth®, and other appropriate systems, as well as next-generation systems extended 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).

[0101] The processing procedures, sequences, flowcharts, etc., of each aspect / embodiment described herein may be reordered, provided they are consistent with each other. For example, the methods described herein present various step elements in an exemplary order and are not limited to that specific order.

[0102] In this specification, specific operations performed by the base station 10 may, in some cases, be performed by its upper node. In a network consisting of one or more network nodes having a base station 10, it is clear that various operations performed for communication with the terminal 20 can be performed by the base station 10 and at least one of the other network nodes (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 10, the other network node may be a combination of multiple other network nodes (for example, an MME and an S-GW).

[0103] The information or signals described in this disclosure may be output from a higher layer (or lower layer) to a lower layer (or higher layer). They may also be input and output via multiple network nodes.

[0104] 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.

[0105] The determination in this disclosure 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, a comparison with a predetermined value).

[0106] 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.

[0107] 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.

[0108] The information, signals, etc. described in this disclosure may be represented using any of the various different techniques. 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.

[0109] 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.

[0110] The terms “system” and “network” as used in this disclosure are interchangeable.

[0111] Furthermore, the information, parameters, etc., described in this disclosure may be expressed using absolute values, relative values ​​from a given value, or corresponding other information. For example, wireless resources may be indicated by an index.

[0112] 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.

[0113] In this disclosure, terms such as "Base Station (BS)", "wireless base station", "base station equipment", "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.

[0114] A base station can accommodate one or more (e.g., three) cells. If a base station accommodates multiple cells, the entire coverage area of ​​the base station can be divided into multiple smaller areas, each of which may also 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 that provide communication services in that coverage.

[0115] 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.

[0116] In this disclosure, terms such as "Mobile Station (MS)," "user terminal," "User Equipment (UE)," and "terminal" may be used interchangeably.

[0117] 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.

[0118] 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 IoT (Internet of Things) device such as a sensor.

[0119] Furthermore, the term "base station" in this disclosure may be interpreted as "user 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 user terminal is replaced with communication between multiple terminals 20 (which may be called, for example, D2D (Device-to-Device), V2X (Vehicle-to-Everything), etc.). In this case, the terminals 20 may have the functions that the base station 10 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.

[0120] Similarly, the term "user terminal" in this disclosure may be replaced with "base station." In this case, the base station may be configured to have the same functions as the user terminal described above.

[0121] 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, "judgment" and "decision" can include considering something as having been "judged" or "decided" after resolving, selecting, choosing, establishing, comparing, etc. In other words, "judgment" and "decision" can include considering something as having been "judged" or "decided" after some action. Also, "judgment (decision)" can be reinterpreted as "assuming," "expecting," or "considering."

[0122] The terms “connected,” “coupled,” or any variation 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.

[0123] The reference signal can also be abbreviated as RS (Reference Signal), and may be called a pilot depending on the applicable standard.

[0124] 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."

[0125] 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.

[0126] In the configuration of each of the above devices, "means" may be replaced with "part," "circuit," "device," etc.

[0127] 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.

[0128] 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.

[0129] Numerical logic may be communication parameters applied to at least one of the transmission and reception of a signal or channel. Numerical logic 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.

[0130] A slot may consist of one or more symbols in the time domain (such as OFDM (Orthogonal Frequency Division Multiplexing) symbols, SC-FDMA (Single Carrier Frequency Division Multiple Access) symbols, etc.). A slot may also be a time unit based on neurologic.

[0131] A slot may include multiple minislots. Each minislot may consist of one or more symbols in the time domain. Minislots may also be called subslots. Minislots may consist of fewer symbols than a slot. A PDSCH (or PUSCH) transmitted in a time unit larger than a minislot may be called a PDSCH (or PUSCH) mapping type A. A PDSCH (or PUSCH) transmitted using a minislot may be called a PDSCH (or PUSCH) mapping type B.

[0132] 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.

[0133] 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 in existing LTE (1 ms), a period shorter than 1 ms (e.g., 1-13 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.

[0134] Here, TTI refers to, for example, the smallest time unit for scheduling in wireless communication. For example, in an LTE system, the base station schedules each terminal 20 to allocate wireless resources (such as the frequency bandwidth and transmission power available to each terminal 20) in TTI units. However, the definition of TTI is not limited to this.

[0135] 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. 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 TTI.

[0136] Furthermore, if one slot or one mini-slot is referred to as a TTI, then one or more TTIs (i.e., one or more slots or one or more mini-slots) may constitute the minimum time unit for scheduling. In addition, the number of slots (number of mini-slots) that constitute this minimum time unit for scheduling may be controlled.

[0137] A TTI with a time length of 1 ms may be called a normal TTI, a long TTI, a normal subframe, a long subframe, a slot, etc. A TTI shorter than a normal TTI may be called a shortened TTI, a short TTI, a partial or fractional TTI, a shortened subframe, a short subframe, a mini slot, a sub slot, a slot, etc.

[0138] 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.

[0139] 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.

[0140] Furthermore, the time domain of the 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.

[0141] One or more RBs may also be called a Physical RB (PRB), Sub-Carrier Group (SCG), Resource Element Group (REG), PRB pair, RB pair, etc.

[0142] 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.

[0143] A Bandwidth Part (BWP), also known as a partial bandwidth, may represent a subset of consecutive common resource blocks (RBs) for a particular neurology in a given carrier. These common RBs may be identified by an index of the RBs relative to a common reference point of the carrier. The PRBs may be defined and numbered within a given BWP.

[0144] A BWP may include a BWP for UL (UL BWP) and a BWP for DL ​​(DL BWP). One or more BWPs may be set within a single carrier for a UE.

[0145] At least one of the configured BWPs may be active, and the UE does not need to assume that it will transmit or receive a predetermined signal / channel outside of the active BWP. In this disclosure, terms such as "cell" and "carrier" may be read as "BWP".

[0146] 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.

[0147] 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.

[0148] 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."

[0149] 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).

[0150] 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.

[0151] This patent application claims priority based on Japanese Patent Application No. 2024-172842, filed on October 1, 2024, and the entire contents of Japanese Patent Application No. 2024-172842 are incorporated herein by reference.

[0152] 10 Base station 110 Transmitting unit 120 Receiving unit 130 Setting unit 140 Control unit 20 Terminal 210 Transmitting unit 220 Receiving unit 230 Setting unit 240 Control unit 1001 Processor 1002 Storage device 1003 Auxiliary storage device 1004 Communication device 1005 Input device 1006 Output device 2001 Vehicle 2002 Drive unit 2003 Steering unit 2004 Accelerator pedal 2005 Brake pedal 2006 Shift lever 2007 Front wheel 2008 Rear wheel 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 (I / O port)

Claims

1. A terminal comprising: a receiving unit that receives a downlink control channel from a first base station; and a transmitting unit that transmits a random access channel without random access response in a no-contour random access scenario, as instructed in the downlink control channel, to a second base station, wherein the receiving unit further comprises a control unit that receives a message containing timing advance information from the first base station, enables monitoring of the conditions for performing cell switching to the second base station, and, if the conditions are met, uses the timing advance information to perform the settings for the cell switching.

2. The terminal according to claim 1, wherein the message is a newly defined first message or a second message that reuses a message from an existing specification, and the second message includes information for distinguishing between a network trigger LTM (Lower-Layer Triggered Mobility) and a terminal trigger LTM.

3. The terminal according to claim 1, wherein the receiving unit receives messages containing timing advance information from a plurality of base stations, and the control unit stores a plurality of timing advance information received from the plurality of base stations in its own device.

4. The terminal according to claim 1, wherein the control unit uses the timing advance information to perform cell switching by LTM without executing a random access procedure.

5. A base station comprising: a transmitting unit that transmits a downlink control channel to a terminal instructing it to transmit a random access channel without a random access response in a non-contour random access; a receiving unit that receives a first message containing timing advance information from another base station that received the random access channel; and the transmitting unit transmitting a second message containing the timing advance information to the terminal.

6. A communication method performed by a terminal comprising: receiving a downlink control channel from a first base station; transmitting a random access channel to a second base station, which is a random access channel without random access response in a no-contour random access environment as instructed in the downlink control channel; receiving a message containing timing advance information from the first base station; and enabling monitoring of the conditions for performing cell switching to the second base station, and if the conditions are met, using the timing advance information to perform the settings for the cell switching.

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