Terminal, base station, and communication method

Abstract

This terminal comprises: a control unit that detects that a random access (RA) executed using a RA channel resource based on sub-band full duplex has failed; a reception unit that receives, from a base station, a request message requesting a report relating to the RA executed using the RA channel resource based on sub-band full duplex; and a transmission unit that transmits a response message in response to the request message, the response message including a notification indicating a failure type for the failure and a notification indicating whether an instruction relating to a RA occasion type was received from the base station.

Description

Terminal, Base Station, and Communication Method

[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), to achieve further increase in system capacity, further increase in data transmission rate, further reduction in delay in a radio section, and the like, studies are underway on a radio communication scheme called 5G or NR (New Radio) (hereinafter, this radio communication scheme is referred to as "NR"). In 5G, various radio technologies and network architectures are being studied to satisfy the requirement that the delay in the radio section be 1 ms or less while achieving a throughput of 10 Gbps or more (see, for example, Non-Patent Document 1 and Non-Patent Document 2).

[0003] 3GPP TS 38.300 V18.4.0 (2024-12) 3GPP TS 38.401 V18.4.0 (2024-12) 3GPP TS 38.331 V18.4.0 (2024-12)

[0004] In 3GPP Rel-19, studies are being conducted on Sub-Band Full Duplex (SBFD) operation on the base station side within a TDD carrier. In SBFD, it is possible to simultaneously perform communication in an uplink and a downlink using resources of sub-bands divided into a plurality of bands.

[0005] However, in existing specifications, information to be included in an RA report when random access performed by a terminal using a random access channel (RACH) resource based on SBFD fails is not defined. As a result, there is a possibility that appropriate measures cannot be taken in response to a random access failure.

[0006] The present invention has been made in view of the foregoing points, and an object of the present invention is to define information included in a report when random access performed using a random access channel resource based on Sub-Band Full Duplex (SBFD) fails in a wireless network.

[0007] The disclosed technology provides a terminal having: a control unit that detects that an RA performed using a subband full-duplex random access (RA) channel resource has failed; a receiving unit that receives a request message from a base station requesting a report regarding the RA performed using a subband full-duplex RA channel resource; and a transmitting unit that transmits a response message to the request message, which includes a notification indicating the type of failure for the failure and a notification indicating whether or not an instruction regarding the type of RA opportunity has been received from the base station.

[0008] According to the disclosed technology, it is possible to define the information to be included in the report when a random access attempt performed using subband full-duplex (SBFD) random access channel resources fails in a wireless network.

[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 a diagram illustrating an RO added in SBFD. This is a diagram showing an example of a sequence diagram in an embodiment of the present invention. This is a diagram showing an example of setting information related to SBFD RACH resources in an embodiment of the present invention. This is a diagram showing an example of the functional configuration of the base station 10 in an embodiment of the present invention. This is a diagram showing an example of the functional configuration of the terminal 20 in an embodiment of the present invention. This is a diagram showing 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 showing 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 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 base station 10 and terminal 20 are capable of applying MIMO (Multiple Input Multiple Output) communication to DL or UL. Furthermore, both the base station 10 and the terminal 20 may communicate via secondary cells (SCell) and primary cells (PCell) using Carrier Aggregation (CA). In addition, the terminal 20 may communicate via the primary cell of base station 10 and the primary secondary cell group cell (PSCell) of another base station 10 using Dual Connectivity (DC).

[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. Also, "network" may mean base station 10, or base station 10 may mean network.

[0021] In 3GPP, it is agreed that at the start of transmission on a Contention Based Random Access Channel (CBRA), the network must specify the type of Random Access Channel Occasion (RA) (RO type) to SBFD-compatible terminals. Here, the RO type indicates whether the channel is SBFD-incompatible (legacy) or not.

[0022] Figure 3 is a diagram illustrating the additional ROs in SBFD. As shown in Figure 3, when SBFD is supported, additional ROs are set for resources where DL (Down Link) and UL (Up Link) overlap in time, compared to the ROs in the case of not supporting SBFD (legacy).

[0023] Furthermore, if the RO type is not specified by the network, it is agreed that the terminal will select the RO type based on the SSB RSRP threshold. However, there is no agreement on whether the network will further specify the selection of an Additional RO when supporting SBFD, or whether this will be determined based on the SSB RSRP threshold.

[0024] Furthermore, the existing specifications do not define the information to be included in the RA report (RA report) when a random access attempt performed by a terminal using a Random Access Channel (RACH) resource via SBFD fails.

[0025] (Example) This example defines the information to be included in the report when a random access attempt performed using a subband full-duplex (SBFD) random access channel resource fails.

[0026] Figure 4 shows an example of a sequence diagram in an embodiment of the present invention. In this sequence, terminal 20 may be NCR (Network-Controlled Repeater)-MT (Mobile Termination) / IAB (Integrated Access and Backhaul)-MT / WAB (Wireless Access and Backhaul)-MT. Also, base station 10 may be IAB-donor / BH (Backhaul)-gNB. The processing of each step in Figure 4 will be described below.

[0027] S101: Terminal 20 detects that a random access attempt performed using a random access channel resource via SBFD has failed.

[0028] S102: The base station 10 sends a request message (UE information request) to the terminal 20 requesting terminal information, including a report (ra-ReportReq) regarding random access performed using the random access channel resource via SBFD.

[0029] S103: Terminal 20 sends a response message (UE information response) to base station 10 for the request message received in S102. This response message includes a report on the random access channel (ra-Report). The information that terminal 20 includes in this report is described below.

[0030] Terminal 20 may include in the report an indication of the failure type for the failure detected in S101, i.e., a failure of random access performed using SBFD-based random access channel resources (SBFD RACH failure). The failure type may be information indicating, for example, a failure to send / receive a message in the random access procedure, or the inability to receive a message within a specified time.

[0031] Terminal 20 may include configuration information regarding the SBFD-based random access channel resource (RACH resource) used in the report. Figure 5 shows an example of configuration information regarding the SBFD RACH resource in an embodiment of the present invention. As shown in Figure 5, the configuration information may include at least one piece of information regarding message 1 (Msg1) in the SBFD-based four-step random access procedure described below. Furthermore, the information may be a parameter in a newly defined Information Element (IE) in the RRC.- Start (minimum) frequency of RO in contested random access (CBRA) (SBFD-Msg1-RO-FrequencyStart) - Start frequency in non-contradiction random access (CFRA) (SBFD-Msg1-FrequencyStartCFRA) - Subcarrier spacing (SBFD-Msg1-SubcarrierSpacing) - Number of Msg1 PRACH transmission opportunities frequency-division multiplexed within one time instance for a PRACH resource configured for CBRA (SBFD-Msg1-RO-FDM) - Number of Msg1 PRACH transmission opportunities frequency-division multiplexed within one time instance for a PRACH resource configured for CFRA (SBFD-Msg1-RO-FDMCFRA) - Subcarrier spacing derived from the PRACH configuration index (SBFD-Msg1-SCS-From-prach-ConfigurationIndex) - Maximum number of Msg1 transmissions (SBFD-Msg1-TransMax) - Modulation coding scheme (Modulation and The following information is included in the configuration: Coding Scheme index information (SBFD-Msg1-MCS), the number of physical resource blocks allocated to Preamble opportunities (POs) (nrofPRBs-PerSBFD-Msg1-PO), PUSCH time domain allocation (SBFD-Msg1-PUSCH-TimeDomainAllocation), PUSCH start (minimum) frequency (frequencyStartSBFD-Msg1-PUSCH), and the number of Preamble opportunities (POs) (nrofSBFD-Msg1-PO-FDM). Furthermore, as shown in Figure 5, this configuration information may include at least one piece of information relating to message A (MsgA) in the two-step random access procedure by SBFD, as shown below.- Start (minimum) frequency of RO in contested random access (CBRA) (SBFD-MsgA-RO-FrequencyStart) - Start frequency in non-contradiction random access (CFRA) (SBFD-MsgA-FrequencyStartCFRA) - Subcarrier spacing (SBFD-MsgA-SubcarrierSpacing) - Number of frequency-division multiplexed MsgA PRACH transmission opportunities within one time instance for a PRACH resource configured for CBRA (SBFD-MsgA-RO-FDM) - Number of frequency-division multiplexed MsgA PRACH transmission opportunities within one time instance for a PRACH resource configured for CFRA (SBFD-MsgA-RO-FDMCFRA) - Subcarrier spacing derived from the PRACH configuration index (SBFD-MsgA-SCS-From-prach-ConfigurationIndex) - Maximum number of MsgA transmissions (SBFD-MsgA-TransMax) - Modulation coding scheme (Modulation and The Coding Scheme index information (SBFD-MsgA-MCS), the number of physical resource blocks allocated to Preamble opportunities (POs) (nrofPRBs-PerSBFD-MsgA-PO), the time domain allocation for PUSCH (SBFD-MsgA-PUSCH-TimeDomainAllocation), the minimum start frequency for PUSCH (frequencyStartSBFD-MsgA-PUSCH), and the number of Preamble opportunities (POs) (nrofSBFD-MsgA-PO-FDM) are explained by returning to Figure 4.

[0032] Terminal 20 may include in the report an indication of whether or not it has received an RO type indication from base station 10.

[0033] When terminal 20 receives an RO type indication from base station 10, it may include an indication of the received RO type in the report. Here, the RO type indicates whether the RO type is not SBFD-compatible (legacy) or SBFD-compatible (SBFD RO). Here, SBFD-compatible RO may be expressed as additional RO.

[0034] Terminal 20 may include in the report an indication of whether or not it has received an indication from base station 10 to prioritize the additional ROs over legacy ROs.

[0035] Terminal 20 may send an indication of whether or not it has fallen back from SBFD RO to Legacy RO.

[0036] Terminal 20 may include in the report the number of times it performed (tried) RACH using SBFD.

[0037] If terminal 20 falls back from SBFD RO to legacy RO, it may include in the report the number of times it performed RACH by SBFD before falling back to legacy RO.

[0038] When terminal 20 applies RACH by SBFD, it may include in the report an indication of whether the Reference Signal Received Power (RSRP) of the downlink synchronization signal block (DL SSB) exceeds a predetermined threshold.

[0039] When terminal 20 applies RACH by SBFD, it may include in the report an indication of whether the Reference Signal Received Power (RSRP) of the downlink synchronization signal block (DL SSB) has fallen below a predetermined threshold.

[0040] Terminal 20 may include in the report an indication of the RO type (Legacy RO or SBFD RO (additional RO)) used when Terminal 20 performed RACH.

[0041] If terminal 20 switches from a PRACH resource in a non-SBFD symbol to a PRACH resource in an SBFD symbol, it may include an indication of the switch in the report.

[0042] (Effects) The above embodiment makes it possible to define the information to be included in the random access report (RA report) when a random access fails (RACH failure) when a terminal performs random access using a RACH resource via SBFD. The information included in this report is expected to be useful in realizing automatic optimization of SBFD RACH. In other words, the above embodiment makes it possible to define the information to be included in the report when a random access performed using a random access channel resource via subband full duplex (SBFD) fails in a wireless network.

[0043] (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.

[0044] <Base Station 10> FIG. 6 is a diagram illustrating an example of a functional configuration of the base station 10 according to an embodiment of the present invention. As illustrated in FIG. 6, the base station 10 includes a transmitting unit 110, a receiving unit 120, a setting unit 130, and a control unit 140. The functional configuration illustrated in FIG. 6 is merely an example. Any functional classification and any name of functional units may be adopted as long as the operation according to the embodiment of the present invention can be executed.

[0045] The transmitting unit 110 includes a function of generating a signal to be transmitted to the terminal 20 side and wirelessly transmitting the signal. Further, the transmitting unit 110 transmits setting information, instructions, notifications and the like to the terminal 20. The receiving unit 120 includes a function of receiving various signals transmitted from the terminal 20 and acquiring, for example, information of a higher layer from the received signals. Further, the transmitting unit 110 has a function of transmitting PSS, SSS, PBCH, DL / UL control signals and the like to the terminal 20. Further, the receiving unit 120 receives inter-network-node messages from other network nodes.

[0046] The setting unit 130 stores preset setting information and various types of setting information to be transmitted to the terminal 20.

[0047] The control unit 140 performs control related to setting, instruction, and notification as described in the embodiment. A functional unit related to signal transmission in the control unit 140 may be included in the transmitting unit 110, and a functional unit related to signal reception in the control unit 140 may be included in the receiving unit 120.

[0048] <Terminal 20> FIG. 7 is a diagram illustrating an example of a functional configuration of the terminal 20 according to an embodiment of the present invention. As illustrated in FIG. 7, the terminal 20 includes a transmitting unit 210, a receiving unit 220, a setting unit 230, and a control unit 240. The functional configuration illustrated in FIG. 7 is merely an example. Any functional classification and any name of functional units may be adopted as long as the operation according to the embodiment of the present invention can be executed. The transmitting unit 210 and the receiving unit 220 may be collectively referred to as a communication unit.

[0049] 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.

[0050] 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.

[0051] (Hardware Configuration) The block diagrams (Figures 6 and 7) 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 one device or the multiple devices with software.

[0052] 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.

[0053] 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 8 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.

[0054] 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.

[0055] 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.

[0056] 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.

[0057] 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 6 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 7 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.

[0058] 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.

[0059] 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.

[0060] 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.

[0061] 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).

[0062] 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.

[0063] 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.

[0064] Figure 9 shows an example of the configuration of vehicle 2001. As shown in Figure 9, 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.

[0065] 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.

[0066] 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).

[0067] 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.

[0068] 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.).

[0069] 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.

[0070] 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.

[0071] 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.

[0072] 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.

[0073] 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.

[0074] <Configuration relating to this embodiment> (1) A terminal having: a control unit that detects that an RA performed using a subband full-duplex random access (RA) channel resource has failed; a receiving unit that receives a request message from a base station requesting a report regarding the RA performed using a subband full-duplex RA channel resource; and a transmitting unit that transmits a response message to the request message, which includes a notification indicating the type of failure for the failure and a notification indicating whether or not an instruction regarding the type of RA opportunity has been received from the base station. (2) The terminal according to paragraph 1, wherein the transmitting unit further includes in the response message information regarding the first message in a four-step RA procedure, or information regarding message A in a two-step RA procedure, as setting information regarding the subband full-duplex RA resource used. (3) The terminal according to paragraph 1, wherein the transmitting unit further includes in the response message at least one of the following: a notification indicating whether or not it has received instructions regarding the type of RA opportunity from the base station; instructions regarding the type of RA opportunity; and a notification indicating whether or not it has received instructions indicating that additional random access opportunities that support subband codebook indexes should be prioritized over legacy random access opportunities that do not support subband codebook indexes. (4) A base station having: a transmitting unit that transmits a request message to the terminal requesting a report on an RA performed using a subband full-duplex random access (RA) channel resource; and a receiving unit that receives a response message from the terminal to the request message, which includes a notification indicating the type of failure for the failed RA performed and a notification indicating whether or not it has received instructions regarding the type of RA opportunity.(Clause 5) A communication method performed by a terminal comprising: detecting that an RA performed using a subband full-duplex random access (RA) channel resource has failed; receiving a request message from a base station requesting a report regarding the RA performed using a subband full-duplex RA channel resource; and sending a response message to the request message, which includes a notification indicating the type of failure for the failure and a notification indicating whether or not instructions regarding the type of RA opportunity have been received from the base station.

[0075] In any of the embodiments described above, it is possible to define the information to be included in the report when a random access performed using a subband full-duplex (SBFD) random access channel resource fails.

[0076] (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 any suitable storage medium such as random access memory (RAM), flash memory, read-only memory (ROM), EPROM, EEPROM, register, hard disk (HDD), removable disk, CD-ROM, database, server, or other appropriate storage medium.

[0077] Furthermore, notification of information is not limited to the embodiments described herein and may be carried out by other means. For example, notification of information may be carried out by physical layer signaling (e.g., DCI (Downlink Control Information), UCI (Uplink Control Information)), upper 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. Also, RRC signaling may be called RRC messages, and may be, for example, RRC Connection Setup messages, RRC Connection Reconfiguration messages, etc.

[0078] 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).

[0079] 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.

[0080] 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).

[0081] 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.

[0082] 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.

[0083] 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).

[0084] 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.

[0085] 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.

[0086] 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.

[0087] 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.

[0088] The terms “system” and “network” as used in this disclosure are interchangeable.

[0089] Furthermore, the information, parameters, etc., described in this disclosure may be expressed using absolute values, relative values ​​from a given value, or other corresponding information. For example, wireless resources may be indicated by an index.

[0090] 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.

[0091] 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.

[0092] 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.

[0093] 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.

[0094] In this disclosure, terms such as "Mobile Station (MS)," "user terminal," "User Equipment (UE)," and "terminal" may be used interchangeably.

[0095] 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.

[0096] 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.

[0097] 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.

[0098] 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.

[0099] 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."

[0100] 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.

[0101] The reference signal can also be abbreviated as RS (Reference Signal), and may be called a pilot depending on the applicable standard.

[0102] 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."

[0103] 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.

[0104] In the configuration of each of the above devices, "means" may be replaced with "part," "circuit," "device," etc.

[0105] 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.

[0106] 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.

[0107] 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.

[0108] 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.

[0109] 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.

[0110] 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.

[0111] 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.

[0112] 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.

[0113] 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.

[0114] 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.

[0115] 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.

[0116] 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.

[0117] 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.

[0118] 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.

[0119] 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.

[0120] 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.

[0121] 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.

[0122] 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.

[0123] 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".

[0124] 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.

[0125] 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.

[0126] 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."

[0127] 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).

[0128] 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.

[0129] This patent application claims priority based on Japanese Patent Application No. 2025-049231, filed on 25 March 2025, and the entire contents of Japanese Patent Application No. 2025-049231 are incorporated herein by reference.

[0130] 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 control unit that detects that an RA performed using a subband full-duplex random access (RA) channel resource has failed; a receiving unit that receives a request message from a base station requesting a report regarding the RA performed using a subband full-duplex RA channel resource; and a transmitting unit that transmits a response message to the request message, which includes a notification indicating the type of failure for the failure and a notification indicating whether or not instructions regarding the type of RA opportunity have been received from the base station.

2. The terminal according to claim 1, wherein the transmitting unit further includes in the response message information relating to the RA resource used by the subband full duplex, which is information relating to the first message in a four-step RA procedure or information relating to message A in a two-step RA procedure.

3. The terminal according to claim 1, wherein the transmitting unit further includes in the response message at least one of the following: a notification indicating whether or not it has received an instruction from the base station regarding the type of RA opportunity; an instruction indicating whether or not it has received an instruction indicating that additional random access opportunities that support subband codebook indexes should be prioritized over legacy random access opportunities that do not support subband codebook indexes.

4. A base station having: a transmitting unit that transmits a request message to a terminal requesting a report on an RA performed using a subband full-duplex random access (RA) channel resource; and a receiving unit that receives a response message from the terminal to the request message, which includes a notification indicating the type of failure for the failed RA performed and a notification indicating whether or not instructions regarding the type of RA opportunity have been received.

5. A communication method performed by a terminal comprising: detecting that an RA performed using a subband full-duplex random access (RA) channel resource has failed; receiving a request message from a base station requesting a report regarding the RA performed using a subband full-duplex RA channel resource; and sending a response message to the request message, which includes a notification indicating the type of failure for the failure and a notification indicating whether or not instructions regarding the type of RA opportunity have been received from the base station.

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