Communication device, and, communication method

Description

53 COMMUNICATION DEVICE AND COMMUNICATION METHOD CROSS-REFERENCE TO RELATED APPLICATIONS

[001] This application is based on, and claims the benefit of priority from, Japanese Patent Application 2021-106434, filed on June 28, 2021, the full contents of which are incorporated herein by reference. TECHNICAL FIELD

[002] The present description refers to a communication device, a base station and a communication method used in a mobile communication system. FUNDAMENTALS OF THE INVENTION

[003] In recent years, in the 3rd Generation Partnership Project (3GPP) (registered trademark) (the same applies hereafter), which is a project to standardize the mobile communication system, the introduction of multipoint transmit / receive (TRP) transmission has been studied as an extension of multiple input - multiple output (MIMO) (see Non-Patent Literature 1).

[004] In multi-TRP transmission, a cell is configured by a plurality of TRPs provided in a distributed manner, and radio communication with a communication device is performed by simultaneously using the plurality of TRPs, according to which efficient transmission can be implemented. It has been proposed to perform beam fault detection and recovery, which until now were performed at the cell level, at the TRP level during such cell operation with a plurality of TRPs (see Non-Patent Literature 2 and 3). The TRP can be referred to as a panel or antenna panel. LIST OF CITATIONS Unpatent Literature

[005] Non-Patent Literature 1: 3GPP Contribution RP-202803 “Summary for WI: Enhancement on MIMO for NR”. Petition 870250048885, dated 11 / 06 / 2025, p. 9 / 74 / 53

[006] Non-Patent Literature 2: 3GPP Contribution R2-2105870 “Beam failure with mTRP”.

[007] Non-Patent Literature 3: 3GPP Contribution R2-2105341 “Discussion on the impacts of the TRP-specific BFR RAN2 specification”. SUMMARY

[008] In order to properly perform beam fault detection and recovery at the TRP level, it is necessary to define a specific behavior to perform beam fault detection and recovery at the TRP level in the communication device.

[009] Therefore, an objective of the present description is to provide a communication apparatus, a base station and a communication method that enable appropriate beam fault detection and recovery at the TRP level during cell operation with a plurality of TRPs.

[0010] A communication apparatus according to a first characteristic performs radio communication with a base station that manages a cell that includes N (N > 2) transmit / receive points. The communication apparatus comprises: a communicator configured to receive a radio resource control (RRC) message from the base station, the RRC message including information to configure N beam fault detection resource sets; and a controller configured to individually detect beam fault for each of the N beam fault detection resource sets. The controller is configured to trigger beam fault recovery (BFR) for a beam fault detection resource set with which the beam fault was detected.The controller is configured to cancel all BFRs triggered for a set of beam fault detection features in a case where a Media Access Control (MAC) protocol data unit (PDU) is transmitted, the MAC protocol data unit (PDU) including a MAC BFR control element (CE). Petition 870250048885, dated 11 / 06 / 2025, p. 10 / 74 / 53 includes information regarding the detected beam failure.

[0011] A base station according to a second characteristic manages a cell that includes N (N > 2) transmit / receive points. The base station comprises: a transmitter configured to transmit, to a communication device, a radio resource control (RRC) message that includes information to configure N beam fault detection resource sets; and a controller configured to control communication with the communication device. Each of the N beam fault detection resource sets is used for individually detecting beam faults in the communication device. The controller is configured to control to trigger beam fault recovery (BFR) for a beam fault detection resource set with which beam faults were detected.The controller is configured to cancel all BFRs triggered by a set of beam fault detection features in a case where a Media Access Control (MAC) protocol data unit (PDU) is transmitted, the MAC protocol data unit (PDU) including a MAC BFR control element (CE) that includes information regarding the detected beam fault.

[0012] A communication method according to a third characteristic is performed by a communication device that performs radio communication with a base station that manages a cell that includes N (N > 2) transmit / receive points. The communication method comprises the steps of: receiving a radio resource control (RRC) message from the base station, the RRC message including information to configure N beam fault detection resource sets; individually detecting the beam fault for each of the N beam fault detection resource sets; triggering beam fault recovery (BFR) for a beam fault detection resource set with which the beam fault was detected; and canceling all BFRs triggered for the Petition 870250048885, dated 11 / 06 / 2025, p. 11 / 74 / 53 a set of beam fault detection features in a case where a Media Access Control (MAC) protocol data unit (PDU) is transmitted, the MAC protocol data unit (PDU) including a MAC BFR control element (CE) that includes information regarding the detected beam fault. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The objectives, characteristics and advantages set forth, and others, of this description will become clearer from the following detailed description in relation to the attached drawings. The drawings are as follows.

[0014] Figure 1 is a diagram that illustrates a configuration of a mobile communication system according to a modality.

[0015] Figure 2 is a diagram that illustrates an example of a protocol stack configuration in a mobile communication system according to a modality.

[0016] Figure 3 is a diagram illustrating an example of operation in a case where beam failure is detected in a secondary cell (SCell) during single-point transmit / receive (TRP) cell operation.

[0017] Figure 4 is a diagram illustrating an example of operation in a case where beam failure is detected in a special cell (SpCell) during cell operation with a single TRP.

[0018] Figure 5 is a diagram illustrating a multi-TRP transmission sketch according to one mode.

[0019] Figure 6 is a diagram illustrating a UE configuration according to a modality.

[0020] Figure 7 is a diagram that illustrates a base station configuration according to a mode.

[0021] Figure 8 is a diagram that illustrates an operation of Petition 870250048885, dated 11 / 06 / 2025, page 12 / 74 / 53 beam failure detection (BFD) at the TRP level according to a modality.

[0022] Figure 9 is a diagram that illustrates an example of a radio resource control (RRC) message configuration according to a mode.

[0023] Figure 10 is a diagram that illustrates the operation of BFD at the TRP level according to a modality.

[0024] Figure 11 is a diagram that illustrates an example of a bandwidth share (BWP) configuration (BWP-DownlinkDedicated) according to a modality.

[0025] Figure 12 is a diagram that illustrates an example of configuring a BFD configuration list (BFD-ConfigurationList) according to a modality.

[0026] Figure 13 is a diagram that illustrates an operation in the EU according to a modality.

[0027] Figure 14 is a diagram to describe an operation in a case where a reference signal resource for BFD is not provided according to a modality.

[0028] Figure 15 is a diagram to describe the operation in a case where the reference signal resource for BFD is not provided according to an embodiment.

[0029] Figure 16 is a diagram to describe the operation in a case where the reference signal resource for BFD is not provided according to an embodiment.

[0030] Figure 17 is a diagram to describe coexistence with existing radio link monitoring according to a modality.

[0031] Figure 18 is a diagram that illustrates an example of RRC message configuration according to a modality.

[0032] Figure 19 is a diagram that illustrates an example of Petition 870250048885, dated 11 / 06 / 2025, page 13 / 74 / 53 configuration of a radio link monitoring configuration (RadioLinkMonitoringConfig) according to a modality.

[0033] Figure 20 is a diagram illustrating a comparative example of a BFD / beam fault recovery (BFR) operation on SpCell according to a modality.

[0034] Figure 21 is a diagram illustrating the operation of BFD / BFR in SpCell according to one embodiment.

[0035] Figure 22 is a diagram illustrating the operation of BFD / BFR in SpCell according to one embodiment.

[0036] Figure 23 is a diagram that illustrates a specific example of an operation of a media access control (MAC) entity in the UE according to a modality.

[0037] Figure 24 is a diagram that illustrates the specific example of the operation of the MAC entity in the UE according to a modality. DETAILED DESCRIPTION

[0038] Therefore, one embodiment provides a communication device, a base station and a communication method that enable efficient switching of a PDCCH monitoring condition. (Mobile Communication System)

[0039] First, a configuration of a mobile communication system 1 according to a embodiment will be described in relation to Figure 1. Mobile communication system 1 is, for example, a system that conforms to a technical specification (TS) of the 3rd Generation Partnership Project (3GPP). Next, mobile communication system 1 will be described, as an example, in relation to the 5th Generation (5GS) system of the 3GPP standard, i.e., a mobile communication system based on New Radio (NR).

[0040] The mobile communication system 1 includes a network 10 and a user equipment (UE) 100 that communicates with the network 10. The network 10 Petition 870250048885, dated 11 / 06 / 2025, page 14 / 74 / 53 includes a next-generation radio access network (NG-RAN) 20, which is a 5G radio access network, and a 5G core network (5GC) 30, which is a 5G core network.

[0041] The UE 100 is a device used by a user. The UE 100 is, for example, a mobile device, such as a mobile phone terminal, such as a smartphone, a tablet-type terminal, a notebook-type personal computer (PC), a communication module or a communication card. The UE 100 may be a vehicle (for example, a car or a train) or a device provided in the vehicle. The UE 100 may be a transport body other than a vehicle (for example, a ship or an aircraft) or a device provided in the transport body. The UE 100 may be a sensor or a device provided in the sensor. The UE 100 may be referred to by another name, such as a mobile station, a mobile terminal, a mobile device, a mobile unit, a subscriber station, a subscriber terminal, a subscriber device, a subscriber unit, a wireless station, a wireless terminal, a wireless device, a wireless unit, a remote station, a remote terminal, a remote device, or a remote unit.

[0042] NG-RAN 20 includes a plurality of 200 base stations. Each of the 200 base stations manages at least one cell. A cell forms a minimal unit of a communication area. A cell belongs to a frequency (a carrier frequency) and is formed by a component carrier. The term “cell” can represent a radio communication resource, and it can also represent a communication target of the UE 100. Each 200 base station can perform radio communication with the UE 100 existing in its own cell. The 200 base station communicates with the UE 100 using a RAN protocol stack. The 200 base station provides user plane and NR control plane protocol terminations in the direction of the UE 100 and is connected to 5GC 30 via an NG interface. An NR base station like this 200 can be referred to as a gNodeB. Petition 870250048885, dated 11 / 06 / 2025, page 15 / 74 / 53 (gNB).

[0043] The 5GC 30 includes a core network device 300. The core network device 300 includes, for example, an access and mobility management (AMF) function and / or a user plane function (UPF). The AMF performs mobility management of UE 100. The UPF provides a specialized function for user plane processing. The AMF and UPF are connected to the base station 200 via the NG interface.

[0044] Next, an example of a protocol stack configuration in mobile communication system 1 according to the modality will be described in relation to figure 2.

[0045] A radio section protocol between UE 100 and base station 200 includes a physical layer (PHY), a media access control (MAC) layer, a radio link control (RLC) layer, a packet data convergence protocol (PDCP) layer, and a radio resource control (RRC) layer.

[0046] The PHY layer performs encoding and decoding, modulation and demodulation, antenna mapping and unmapping, and feature mapping and unmapping. Data and control information are transmitted between the UE 100 PHY layer and the base station 200 PHY layer via a physical channel.

[0047] The physical channel includes a plurality of orthogonal frequency-division multiplexing (OFDM) symbols in the time domain and a plurality of subcarriers in the frequency domain. A subframe includes a plurality of OFDM symbols in the time domain. A resource block is a resource allocation unit, and includes a plurality of OFDM symbols and a plurality of subcarriers. A frame may consist of 10 ms, and may include 10 subframes consisting of 1 ms. A number of intervals corresponding to a subcarrier spacing may be included in the subframe. Petition 870250048885, dated 11 / 06 / 2025, page 16 / 74 / 53

[0048] Among the physical channels, a physical downlink control channel (PDCCH) plays a central role for purposes such as, for example, downlink scheduling allocation, uplink scheduling granting, and transmission power control.

[0049] In NR, the UE 100 can use a narrower bandwidth than the system bandwidth (i.e., the cell bandwidth). Base station 200 configures a bandwidth portion (BWP) for the UE 100 that includes consecutive physical resource blocks (PRBs). The UE 100 transmits and receives data and a control signal on an active BWP. On the UE 100, for example, a maximum of four BWPs can be configured. The BWPs can have different subcarrier spacings or can have frequencies overlapping each other. In a case where a plurality of BWPs is configured for the UE 100, base station 200 can designate which BWP should be activated by the control on the downlink. As a result, base station 200 can dynamically adjust the UE's bandwidth according to the amount of data traffic from UE 100 and similar stations, and can reduce the UE's power consumption.

[0050] Base station 200 can configure, for example, a maximum of three control resource sets (CORESETs) for each of a maximum of four BWPs in a service cell. The CORESET is a radio resource for control information to be received by UE 100. A maximum of 12 CORESETs can be configured in the service cell for UE 100. Each CORESET has an index from 0 to 11. For example, the CORESET includes six resource blocks (PRB) and one, two, or three consecutive OFDM symbols in the time domain.

[0051] The MAC layer performs data priority control, retransmission processing via a hybrid automatic repeat request (HARQ), a random access procedure, and similar data and Petition 870250048885, dated 11 / 06 / 2025, page 17 / 74 / 53 control information is transmitted between the MAC layer of UE 100 and the MAC layer of base station 200 via a transport channel. The MAC layer of base station 200 includes a scheduler. The scheduler determines the transport formats of the uplink and downlink (size and modulation and coding scheme (MCS) of the transport block) and resources to be allocated on UE 100.

[0052] The RLC layer transmits data to the RLC layer on one side of the receiver using the functions of the MAC layer and the PHY layer. Data and control information are transmitted between the RLC layer of UE 100 and the RLC layer of base station 200 via a logical channel.

[0053] The PDCP layer performs compression and decompression and header encryption and decryption.

[0054] A Service Data Adaptation Protocol (SDAP) layer can be provided as an upper layer of the PDCP layer. The Service Data Adaptation Protocol (SDAP) layer performs mapping between an IP flow, which is a unit where a core network performs Quality of Service (QoS) control, and a radio carrier, which is a unit where an Access Stratum (AS) performs QoS control.

[0055] The RRC layer controls the logical channel, the transport channel, and the physical channel according to the establishment, re-establishment, and release of the radio carrier. RRC signaling for various configurations is transmitted between the RRC layer of UE 100 and the RRC layer of base station 200. In a case where there is an RRC connection between the RRC layer of UE 100 and the RRC layer of base station 200, UE 100 is in an RRC-connected state. In a case where there is no RRC connection between the RRC layer of UE 100 and the RRC layer of base station 200, UE 100 is in an RRC-idle state. In a case where there is an RRC connection between the RRC layer of UE 100 and the RRC layer of base station 200 Petition 870250048885, dated 11 / 06 / 2025, p. 18 / 74 / 53, is suspended; the EU 100 is in an inactive RRC state.

[0056] A non-accessible layer (NAS) located above the RRC layer performs session management and mobility management of the UE 100. NAS signaling is transmitted between the UE 100 NAS layer and the NAS layer of the 300 central network appliance (AMF). Note that the UE 100 has an application layer and similar, in addition to a radio interface protocol. (Beam Fault Detection and Recovery Outline)

[0057] Next, an outline of beam fault detection and recovery will be described in relation to figures 3 and 4.

[0058] NR can perform broadband transmission in a high-frequency band, such as a millimeter wave band or a terahertz wave band, compared to Long Term Evolution (LTE), which is the fourth-generation radio access technology. In order to compensate for radio wave attenuation for radio waves in a high-frequency band like this, NR uses highly directional beamforming using a large number of antennas between base station 200 and UE 100 to achieve high beam gain. In NR, a beam control technology to establish and maintain a beam pair between base station 200 and UE 100 is introduced. Beam fault detection and recovery technology is one such beam control technology.

[0059] For beam fault detection (BFD), base station 200 configures a downlink reference signal resource for beam fault detection to UE 100. Such a reference signal resource is either a synchronization signal (SS) / PBCH block signal (SSB) or a channel state information reference signal (CSIRS). The SSB includes a primary synchronization signal (PSS), a secondary synchronization signal (SSS), a physical broadcast channel (PBCH), and a demodulation reference signal (DMRS). For example, the SSB might be Petition 870250048885, dated 11 / 06 / 2025, p. 19 / 74 / 53, composed of four consecutive OFDM symbols in the time domain. Furthermore, the SSB can be composed of 240 consecutive subcarriers (i.e., 20 feature blocks) in the frequency domain. PBCH is a physical channel that carries a master information block (MIB). The CSI-RS is a reference signal that is transmitted so that UE 100 mela a state of a radio channel.

[0060] In a case where the SSB is within a band of a downlink BWP, UE 100 can detect beam failure using the SSB. In a case where the SSB is not within the band of the downlink BWP, UE 100 can detect beam failure using the CSI-RS configured from base station 200.

[0061] In UE 100, the MAC layer counts a beam failure event (beam failure instance indication) notified from the physical layer with a counter, and detects (declares) beam failure when the count value becomes greater than or equal to a specified number of times before a timer expires.

[0062] Figure 3 is a diagram illustrating an example of operation in a case where beam failure is detected in a secondary cell (SCell) during single-point transmit / receive (TRP) cell operation.

[0063] Figure 3 illustrates an example where base station 200 manages an SCell 250B which includes a TRP 201. Base station 200 (TRP 201) forms a total of three beams, beams no. 0 and no. 2. UE 100 detects beam failure during communication using beam no. 0 on SCell 250B.

[0064] In this case, the UE 100 triggers beam fault recovery (BFR) by initiating the transmission of a beam fault recovery MAC control element (BFR MAC CE). Here, the UE 100 selects a suitable beam (e.g., beam no. 1) for the SCell, and indicates the selected beam information along with information regarding the Petition 870250048885, dated 11 / 06 / 2025, p. 20 / 74 / 53 beam failure by the BFR MAC CE. When UE 100 receives the PDCCH indicating uplink grant for new transmission of the HARQ process used for the transmission of the BFR MAC CE, beam failure recovery on SCell 250B is completed.

[0065] Figure 4 is a diagram illustrating an example of operation in a case where beam failure is detected in a special cell (SpCell) during cell operation with a single TRP. SpCell may be referred to as a primary cell (PCell).

[0066] Figure 4 illustrates an example where base station 200 manages a SpCell 250A which includes a TRP 201. Base station 200 (TRP 201) forms a total of three beams from beams no. 0 to no. 2. UE 100 detects beam failure during communication using beam no. 0 on the SpCell 250A.

[0067] In this case, UE 100 triggers the BFR by initiating a random access procedure for SpCell 250A. Here, UE 100 selects an appropriate beam (e.g., beam #1) to perform BFR. When the random access procedure is completed, the BFR is completed. (Multi-TRP Transmission Outline)

[0068] Next, an outline of multi-TRP transmission according to the mode will be described in relation to figure 5.

[0069] In multi-TRP transmission, base station 200 configures a cell 250 with a plurality of TRPs 201 provided in a distributed manner. Figure 5 illustrates two TRPs (TRP 201 no. 0 and TRP 201 no. 0) as the plurality of TRPs 201. However, base station 200 can configure a cell 250 with three or more TRPs 201. A case where the number of TRPs 201 included in a cell 250 is two will be described below.

[0070] In multi-TRP transmission, different pieces of data are transmitted from the plurality of 201 TRPs to achieve spatial multiplexing, and a data rate can be increased. Alternatively, it is also Petition 870250048885, dated 11 / 06 / 2025, page 21 / 74 / 53, it is possible to transmit the same data from multiple TRPs 201 to achieve diversity, thereby improving the reliability and robustness of the transmission.

[0071] For multi-TRP transmission, there is a scheme that uses a single PDCCH and a scheme that uses a plurality of PDCCHs. In the scheme that uses a single PDCCH, a TRP 201 transmits a PDCCH (downlink control information (DCI)) and schedules a set of shared channel layers on the physical uplink (PDSCH) for each TRP 201. On the other hand, in the scheme that uses a plurality of PDCCHs, each TRP 201 individually schedules its own PDSCH. The following scheme that uses a plurality of PDCCHs is mostly assumed.

[0072] In the scheme that uses a plurality of PDCCHs, a different CORESET can be configured for each TRP 201. Specifically, the TRP 201 and a CORESET concentration index are associated on a one-to-one basis. During the CORESET configuration for UE 100, base station 200 notifies UE 100 of the CORESET concentration index to which the CORESET belongs. As such, the CORESET concentration index can be considered as an index that identifies the TRP 201.

[0073] In this mode, during such a cell operation using a plurality of TRPs 201, BFD / BFR that were now performed at the 250 cell level are considered to be performed at the TRP 201 level. Specifically, a specific TRP 201 counter / timer for beam fault detection is introduced, and in UE 100, the notified beam fault instance indication from the physical layer to the MAC layer is counted with the counter, and the beam fault is detected when the count value becomes greater than or equal to a specified number of times before the timer expires. Petition 870250048885, dated 11 / 06 / 2025, p. 22 / 74 / 53

[0074] It is considered necessary to individually configure, for the UE 100, a beam fault detection feature set (hereinafter referred to as a “BFD feature set”) that includes a beam fault detection reference signal feature for each TRP 201 in order to perform such BFD / BFR at the TRP 201 level. However, in the existing 3GPP technical specification, there is no mechanism to configure, for the UE 100, the BFD feature set for each TRP 201. In one embodiment, BFD / BFR can be performed at the TRP 201 level.

[0075] Furthermore, in a case where it is essential to individually configure, for the UE 100, the reference signaling resource for BFD for each TRP 201, there is a possibility that the amount of signaling for BFD / BFR will increase. In one embodiment, a mechanism that enables BFD / BFR is also implemented for a set of BFD or TRP 201 resources from which or for which no reference signaling resource for BFD is provided.

[0076] Furthermore, existing radio link monitoring (i.e., radio link fault (RLF) detection and beam fault detection) is performed, not at the TRP 201 level, but at the cell 250 level. In one embodiment, it is possible to enable appropriate coexistence of an existing technology such as this and BFD at the TRP 201 level.

[0077] Furthermore, even in a case where UE 100 detects a beam failure for all TRPs 201, communication (data transmission / reception) can be performed as long as any of the TRPs 201 recovers from the beam failure. In a case where the random access procedure for recovery from the beam failure is initiated without considering whether recovery from the beam failure occurred or not, data transmission / reception cannot be performed during the random access procedure, and communication is interrupted. In one embodiment, it is possible to suppress such a communication interruption. Petition 870250048885, dated 11 / 06 / 2025, p. 23 / 74 / 53 (Configuration of the Communication Device)

[0078] Next, an example of a UE 100 configuration according to a mode will be described in relation to figure 6. The UE 100 includes a communicator 110 and a controller 120.

[0079] Communicator 110 performs radio communication with base station 200 by transmitting and receiving a radio signal to and from base station 200. Communicator 110 includes at least one transmitter 111 and at least one receiver 112. Transmitter 111 and receiver 112 may include a plurality of antennas and a radio frequency (RF) circuit. The antenna converts a signal into a radio wave and emits the radio wave into space. Furthermore, the antenna receives a radio wave in space and converts the radio wave into a signal. The RF circuit performs analog processing of a signal transmitted and received through the antenna. The RF circuit may include a high-frequency filter, an amplifier, a modulator, a low-pass filter, and the like.

[0080] Controller 120 performs various types of controls on UE 100. Controller 120 controls communication with base station 200 via communicator 110. The UE 100 operation described above and below may be an operation under the control of controller 120. Controller 120 may include at least one processor capable of executing a program and a memory that stores the program. The processor may execute the program to perform the operation of controller 120. Controller 120 may include a digital signal processor that performs digital processing of a signal transmitted and received via the antenna and RF circuit. The digital processing includes processing of the RAN protocol stack. The memory stores the program executed by the processor, a program-related parameter, and program-related data.The memory may include at least one type of read-only memory (ROM), one type of erasable programmable read-only memory (EPROM). Petition 870250048885, dated 11 / 06 / 2025, page 24 / 74 / 53, a programmable and electrically erasable read-only memory (EEPROM), a random access memory (RAM), or a flash memory. All or part of the memory may be included in the processor.

[0081] In UE 100 according to one embodiment, communicator 110 performs radio communication with base station 200 which manages cell 250 which has N TRPs 201 (N > 2). Communicator 110 receives, from base station 200, an RRC message that includes a beam fault detection configuration (hereinafter referred to as a “BFD configuration list”), which is information to configure N sets of BFD resources and is associated with a downlink BWP, which is a portion of the bandwidth of cell 250. Controller 120 individually detects beam faults for each of the N sets of BFD resources in radio communication using the downlink BWP. As a result, during the operation of cell 250 with the plurality of TRPs 201, the set of BFD resources for each TRP 201 can be configured for UE 100 in the RRC layer, so that BFD / BFR can be performed at the TRP 201 level.As a result, even if a failure occurs in one TRP 201, communication can continue with the other TRP 201, thus strengthening the communication's resilience to failure.

[0082] Furthermore, in UE 100 according to one embodiment, in a case where there is a BFD feature set that does not provide a reference signal resource for beam fault detection, controller 120 detects beam fault for the BFD feature set by using a predetermined reference signal resource instead of the reference signal resource. For example, controller 120 specifies a state of the active transmission configuration indication (TCI) for a PDCCH based on a CORESET concentration index associated with the BFD feature set, and detects beam fault for the BFD feature set by Petition 870250048885, dated 11 / 06 / 2025, page 25 / 74 / 53 use of a reference signal resource indicated by the active TCI state as the predetermined reference signal resource. As a result, during the operation of cell 250 using the plurality of TRPs 201, BFD / BFR can also be performed for a TRP for which the reference signal resource is not provided. As a result, the amount of signaling can be reduced.

[0083] Furthermore, in UE 100 according to one embodiment, communicator 110 receives, from base station 200, an RRC message that includes a radio link monitoring configuration to configure radio link monitoring at the 250 cell level and a BFD configuration list to configure N sets of BFD features. Controller 120 detects the RLF at the 250 cell level based on the radio link monitoring configuration, and individually detects the beam failure for each of the N sets of BFD features 521 no. 0 and 521 no. 1 based on a 520 BFD configuration list. As a result, during the operation of cell 250 with the plurality of TRPs 201, radio link monitoring at the 250 cell level and BFD at the TRP 201 level can coexist appropriately.As a result, it is possible to implement two-stage fault detection and recovery based on RLF detection and recovery at the 250 cell level and BFD / BFR at the 201 TRP level, thereby increasing the communication's fault resistance.

[0084] Furthermore, in UE 100 according to one embodiment, in a case where beam failure is detected for all N sets of BFD features, controller 120 determines whether or not to initiate the random access procedure for cell 250 (specifically, the SpCell) based on a recovery state from the beam failure. For example, controller 120 that has detected beam failure for one set of BFD features detects beam failure for another set. Petition 870250048885, dated 11 / 06 / 2025, p. 26 / 74 / 53 of BFD resources, and initiates the random access procedure for cell 250 only in a case where there has been no recovery from the beam failure for any of the BFD resource sets. As a result, communication can be continued as long as possible by reflecting the BFR state as a condition to initiate the random access procedure. (Base Station Configuration)

[0085] Next, a configuration of base station 200 according to one mode will be described in relation to figure 7. Base station 200 includes N TRPs 201 (TRP 201 no. 0 and TRP 201 no. 1 in the example of figure 7), a communicator 210, a network interface 220 and a controller 230.

[0086] Each TRP 201 includes a plurality of antennas and has beamforming capability. The TRP 201 may be referred to as a panel or antenna array. The antenna converts a signal into a radio wave and emits the radio wave into space. Furthermore, the antenna receives a radio wave in space and converts the radio wave into a signal. The TRPs 201 are arranged in a dispersed manner and are included in a cell of 250. In a case where base station 200 manages a plurality of cells, base station 200 may have N TRPs 201 for each cell.

[0087] For example, communicator 210 receives a radio signal from UE 100 and transmits a radio signal to UE 100. Communicator 210 includes at least one transmitter 211 and at least one receiver 212. Transmitter 211 and receiver 212 may include an RF circuit. The RF circuit performs analog processing of a signal transmitted and received through the antenna. The RF circuit may include a high-frequency filter, an amplifier, a modulator, a low-pass filter, and the like.

[0088] Network interface 220 transmits and receives a signal to and from a network. Network interface 220 receives, for example, a signal from a neighboring base station connected via an Xn interface, Petition 870250048885, dated 11 / 06 / 2025, page 27 / 74 / 53, which is an interface between base stations, and transmits the signal to the neighboring base station. Furthermore, network interface 220 receives, for example, a signal from the central network device 300 connected via the NG interface, and transmits the signal to the central network device 300.

[0089] Controller 230 performs various types of control on base station 200. Controller 230 controls, for example, communication with UE 100 via communicator 210. Furthermore, controller 230 controls, for example, communication with a node (e.g., the neighboring base station and the central network device 300) via network interface 220. The operation of base station 200 described above and described below may be an operation under the control of controller 230. Controller 230 may include at least one processor capable of executing a program and a memory that stores the program. The processor may execute the program to perform the operation of controller 230. Controller 230 may include a digital signal processor that performs digital processing of a signal transmitted and received via an antenna and an RF circuit. Digital processing includes processing of the RAN protocol stack.Memory stores the program executed by the processor, a parameter related to the program, and data related to the program. All or part of the memory may be included in the processor.

[0090] Base station 200, according to a modality, manages cell 250, including N TRPs 201, and performs radio communication with UE 100. Communicator 210 transmits to UE 100 the RRC message, including a BFD configuration list, which is a list to configure N sets of BFD features and is associated with a downlink BWP, which is a portion of the bandwidth of cell 250. The BFD configuration list is used by UE 100 to individually detect beam failure for each of the N sets of BFD features in radio communication using the downlink BWP. In Petition 870250048885, dated 11 / 06 / 2025, p. 28 / 74 / 53. As a result, during the operation of cell 250 with the plurality of TRPs 201, the set of BFD resources for each TRP 201 can be configured for UE 100 at the RRC layer, so that UE 100 can perform BFD / BFR at the TRP 201 level. Consequently, even in the event of a failure in one TRP 201, UE 100 can continue communication with the other TRP 201, so that communication failure resilience can be enhanced.

[0091] Furthermore, at base station 200 according to a mode, controller 230 generates the RRC message including the radio link monitoring configuration to configure radio link monitoring at the cell level 250 and the BFD configuration list to configure N sets of BFD features. Communicator 210 transmits the RRC message to UE 100. The radio link monitoring configuration includes information indicating the reference signal feature and information indicating the purpose of the reference signal feature. In a case where UE 100 is configured with the BFD configuration list, controller 120 sets RLF detection as the purpose of the reference signal feature in the radio link monitoring configuration without configuring beam failure detection.As a result, during the operation of cell 250 with the plurality of TRPs 201, radio link monitoring at the cell 250 level and BFD at the TRP 201 level can coexist appropriately. Consequently, UE 100 can implement two-stage fault detection and recovery based on RLF detection and recovery at the cell 250 level and BFD / BFR at the TRP 201 level, thus enhancing communication fault resilience. (Beam Fault Detection Operation at the TRP Level)

[0092] Next, a BFD operation at the TRP 201 level according to a modality will be described in relation to figures 8 to 10. Petition 870250048885, dated 11 / 06 / 2025, p. 29 / 74 / 53

[0093] As illustrated in Figure 8, in step S101, base station 200 (communicator 210) managing cell 250, including N TRPs 201, transmits to UE 100 the RRC message including the BFD configuration list, which is a list to configure N sets of BFD resources and is associated with the downlink BWP, which is a portion of the bandwidth of cell 250. UE 100 (communicator 110) receives the RRC message. Note that the RRC message can be a UE-specific RRC message, and can be, for example, an RRC Reconfiguration message.

[0094] By associating the downlink BWP with the BFD configuration list in this way, the BFD configuration list can be individually configured for each downlink BWP. Therefore, an ideal BFD configuration list can be adjusted according to a requirement for the downlink BWP.

[0095] In step S102, UE 100 (controller 120) individually detects beam failure for each of the N sets of BFD features based on the BFD configuration list configured by base station 200 in radio communication using downlink BWP (beam monitoring). In a case where beam failure is detected for any of the sets of BFD features, UE 100 (controller 120) initiates (triggers) a BFR procedure for recovery from the detected beam failure.

[0096] As illustrated in Figure 9, the RRC message according to a modality includes a Downlink Dedicated (BWP) 500 configuration to configure the Downlink Dedicated (BWP) (specifically, a UE-specific Downlink Dedicated) BWP) for UE 100. The BWP (BWPDownlinkDedicated) 500 configuration is an information element to configure a UE-specific parameter of the Downlink Dedicated BWP. The configurationPetition 870250048885, dated 11 / 06 / 2025, page 30 / 74 / 53 of BWP (BWP-DownlinkDedicated) 500 may include a Radio Link Monitoring configuration (RadioLinkMonitoringConfig) 510 to configure radio link monitoring at the cell level 250 and the BFD configuration list (BFD-ConfigurationList) 520 to configure N sets of BFD features. By including the BFD configuration list (BFD-ConfigurationList) 520 in the BWP (BWPDownlinkDedicated) 500 configuration, the BFD configuration list (BFDConfigurationList) 520 can be configured for each downlink BWP configured for UE 100.In a case where the downlink BWP configured in the BWP configuration (BWPDownlinkDedicated) 500 is used for radio communication, that is, in a case where the downlink BWP is an active BWP, UE 100 (controller 120) performs beam monitoring by using the BFD configuration list (BFD-ConfigurationList) 520 associated with the downlink BWP.

[0097] Here, the BFD configuration list (BFD-ConfigurationList) 520 is a different information element from the Radio Link Monitoring configuration (RadioLinkMonitoringConfig) 510. Specifically, the Radio Link Monitoring configuration (RadioLinkMonitoringConfig) 510 is an information element defined in the existing technical specification, and the BFD configuration list (BFDConfigurationList) 520 is a new information element not defined in the existing technical specification. In this way, by introducing a new information element for BFD at the TRP 201 level, BFD at the TRP 201 level becomes possible, and coexistence with existing radio link monitoring becomes possible.

[0098] The BFD configuration list (BFD-ConfigurationList) 520 includes N sets of BFD features (BFD Feature Sets) 521. For example, in a case where N = 2, the BFD configuration list Petition 870250048885, dated 11 / 06 / 2025, page 31 / 74 / 53 (BFD-ConfigurationList) 520 includes two BFD feature sets (BFD Feature Sets) 521 #0 and 521 #1. Each BFD feature set (BFD Feature Set) 521 includes a downlink reference signal resource. The reference signal resource is either an SSB or a CSI-RS. Here, the reference signal resource in BFD feature set (BFD Feature Set) 521 is configured as a reference signal resource used to detect beam failure. In other words, the reference signal resource in BFD feature set (BFD Feature Set) 521 is not configured as a reference signal resource used to detect RLF.As will be described in detail below, in one embodiment, RLF detection is performed at the 250 cell level using the RadioLinkMonitoringConfig 510, and beam fault detection is performed at the 201 TRP level using the BFD-ConfigurationList 520.

[0099] In one embodiment, the N BFD feature sets (BFD Feature Sets) 521 are associated with the N TRPs 201 on a one-to-one basis. For example, BFD feature set (BFD Feature Set) 521 no. 0 is associated with TRP 201 no. 0, and BFD feature set (BFD Feature Set) 521 no. 1 is associated with TRP 201 no. 1. This enables BFD at the TRP 201 level.

[00100] Furthermore, in one embodiment, each BFD feature set (BFD Feature Set) 521 may include one or more reference signal features, and each of the one or more reference signal features may be associated with a beam on a one-to-one basis. For example, as illustrated in Figure 10, TRP 201 No. 0 is considered to form three beams No. 0 and No. 2, and TRP 201 No. 1 forms three beams No. 0 and No. 2. In such a case, base station 200 (controller 230) configures, for UE 100, the BFD feature set (BFD Feature Set) 521 Petition 870250048885, dated 11 / 06 / 2025, p. 32 / 74 / 53 No. 0 associated with TRP 201 No. 0 and the BFD Resource Set (BFD Resource Set) 521 No. 1 associated with TRP 201 No. 1 by RRC message. Therefore, base station 200 (controller 230) configures three reference signal resources associated with the three beams #0 and #2 on a one-to-one basis in the BFD resource set #0. Furthermore, base station 200 (controller 230) configures three reference signal resources associated with the three beams #0 and #2 on a one-to-one basis in the BFD resource set #1. As a result, UE 100 (controller 120) can detect beam failure for each TRP 201 and for each beam.

[00101] Next, a specific example of the RRC message according to a modality will be described in relation to figures 11 and 12. Figures 11 and 12 illustrate examples of description in the technical specification (TS 38.331) of the 3GPP RRC layer.

[00102] As illustrated in Figure 11, the BWP (BWP-DownlinkDedicated) configuration 500 to configure BWP on a specific UE downlink to UE 100 may include the RadioLinkMonitoringConfig configuration 510 to configure radio link monitoring at the cell level 250 and the BFD configuration list (BFD-ConfigurationList-r17) 520 to configure N sets of BFD features. Here, “-r17” signifies an information element introduced in Edition 17 of the 3GPP standard, but it may also be an information element introduced in Edition 18 or later. Hereafter, the “-r17” notation is appropriately omitted.

[00103] Note that the BFD configuration list (BFDConfigurationList) 520 configured for UE 100 can be released by a release instruction from base station 200. For example, in a case of changing the cell operation with a plurality of TRPs to the Petition 870250048885, dated 11 / 06 / 2025, page 33 / 74 / 53: In a single TRP cell operation, base station 200 transmits to UE 100 the release instruction for the BFD configuration list (BFD-ConfigurationList) 520 configured for UE 100. UE 100 releases the configured BFD configuration list (BFD-ConfigurationList) 520 in response to receiving the release instruction.

[00104] As illustrated in figure 12, the BFD configuration list (BFD-ConfigurationList) 520 includes up to maxNrOfBFD-ResourceSets of BFD resource sets (BFD Resource Sets) 521.

[00105] Each BFD resource set (BFD Resource Set) 521 may include a BFD resource set identifier (bfdResourceSetId) that identifies the BFD resource set, an add / modify list (bfd-ResourcesToAddModList) to add / modify one or a plurality of reference signal resources, a release list (bfd-ResourcesToReleaseList) to release one or a plurality of reference signal resources, a maximum count value (beamFailureInstanceMaxCountPerRS) of beam fault instance indications from the physical layer, and a timer value (beamFailureDetectionTimerPerRS) for beam fault detection.

[00106] The BFD resource set identifier (bfdResourceSetId) is an identifier that identifies a BFD resource set. The BFD resource set identifier (bfd-ResourceSetId) can be considered as an identifier that identifies a corresponding TRP 201. The BFD resource set identifier (bfdResourceSetId) can be associated with the CORESET concentration index (coresetPoolIndex) on a one-to-one basis. For example, “0” from the BFD resource set identifier (bfd-ResourceSetId) is associated with “0” from the CORESET concentration index (coresetPoolIndex), and “1” from the BFD resource set identifier (bfd-ResourceSetId) is associated with “1” from the CORESET concentration index. Petition 870250048885, dated 11 / 06 / 2025, page 34 / 74 / 53 CORESET (coresetPoolIndex).

[00107] The add / modify list (bfd-ResourcesToAddModList) is a list of one or a plurality of reference signal resources (BeamFailureDetectionRS) to be added or modified. Specifically, the add / modify list (bfdResourcesToAddModList) is a list of reference signals for beam failure detection, and the limitation of the reference signal that can be adjusted by the network (base station 200) is specified in the technical specification (e.g., Table 5-1 in TS 38.213). The network (base station 200) configures a predetermined maximum number of reference signal resources for each resource set.As will be described in detail below, in a case where no reference signal is provided for BFD purposes for each BFD feature set (BFD Feature Set) 521, the UE 100 performs beam monitoring based on the active TCI state for a PDCCH associated with the corresponding CORESET concentration index (coresetPoolIndex).

[00108] The reference signal resource (BeamFailureDetectionRS) to be configured includes a reference signal resource identifier (beamFailureDetectionRS-Id) that identifies the reference signal resource, and a reference signal resource (detectionResource) that is a reference signal to be used by UE 100 for BFD. The reference signal resource (detectionResource) is configured with an SSB index (ssb-Index) or a CSI-RS index (csi-RS-Index).

[00109] The release list (bfd-ResourcesToReleaseList) is a list of the reference signal resource identifiers (beamFailureDetectionRS-Id) of the reference signal resources to be released.

[00110] The maximum count value (beamFailureInstanceMaxCountPerRS) indicates the number of failure events. Petition 870250048885, dated 11 / 06 / 2025, p. 35 / 74 / 53 beam (i.e., the number of beam failure instance indications from the physical layer) for which UE 100 triggers the BFR procedure. For example, a value “n1” corresponds to one beam failure instance indication and a value “n2” corresponds to two beam failure instances. The timer value (beamFailureDetectionTimerPerRS) is a timer for BFD.

[00111] As described above, in a case where a beam failure event (beam failure instance indication) is reported from the physical layer a specified number of times within a specified time, the UE 100 MAC layer (controller 120) detects the beam failure. Each BFD feature set (BFD Feature Set) 521 includes information to configure the specified time and the specified number of times independently of other BFD feature sets. The maximum count value (beamFailureInstanceMaxCountPerRS) indicating the specified number of times and the timer (beamFailureDetectionTimerPerRS) indicating the specified time are configured for each BFD feature set (BFD Feature Set) 521, that is, for each TRP 201. As a result, a beam failure detection condition can be optimized for each TRP 201.

[00112] As illustrated in Figure 13, in UE 100, the physical layer (PHY) evaluates the radio link quality for each configured BFD resource set. The radio link quality can be a block error rate (BLER) of the PDCCH. For example, in a case where the radio link quality of all reference signal resources in the BFD resource set is below a threshold, the physical layer periodically transmits a beam failure instance indication to the MAC layer, along with the BFD resource set identifier (bfd-ResourceSetId) of the BFD resource set. This period is configured, for example, to the longest of the minimum signal periods. Petition 870250048885, dated 11 / 06 / 2025, page 36 / 74 / 53, reference in the BFD resource set and 2 ms. Note that the BFD resource set identifier (bfd-ResourceSetId) can be used as the beam fault instance indication.

[00113] Each BFD feature set (BFD Feature Set) 521 may include information to adjust the threshold to be compared with the radio link quality measured by the physical layer independently of other BFD feature sets. The physical layer notifies the MAC layer of the beam failure event (beam failure instance indication) that indicates the BFD feature set (BFD Feature Set) 521 in response to the radio link quality in any BFD feature set (BFD Feature Set) 521 that is lower than the threshold associated with the BFD feature set (BFD Feature Set) 521. As a result, the threshold to be compared with the radio link quality can be individually adjusted for each BFD feature set (BFD Feature Set) 521, that is, for each TRP 201, so that the condition for beam failure event detection can be optimized for each TRP 201.

[00114] The MAC layer manages the timer and counter for each configured BFD resource set, and performs BFD / BFR for each BFD resource set. Figure 13 illustrates an example where there are two BFD resource sets, and the MAC layer manages a timer #0 and a counter #0 for a BFD resource set #0 and a timer #1 and a counter #1 for a BFD resource set #1.

[00115] Upon receiving the beam fault instance indication along with the BFD resource set identifier (bfdResourceSetId) from the physical layer, the MAC layer starts the timer corresponding to the BFD resource set identifier (bfd-ResourceSetId) and increments (i.e., adds 1 to) the counter. Petition 870250048885, dated 11 / 06 / 2025, p. 37 / 74 / 53, corresponds to the BFD resource set identifier (bfdResourceSetld). When the counter count value becomes greater than or equal to the specified number of times before the timer expires, the MAC layer detects a beam failure for the BFD resource set corresponding to the counter. Details of such an operation will be described below. (Operation in the case where the Reference Signal Resource Used for Beam Fault Detection is not Provided)

[00116] Next, an operation in a case where the reference signal feature for BFD is not provided according to an embodiment will be described in relation to figures 14 to 16.

[00117] In a case where it is essential to individually configure, for UE 100, the reference signal feature (BeamFailureDetectionRS) for BFD for each TRP 201, there is a possibility that the amount of signaling for BFD will increase. In one embodiment, a mechanism that enables BFD / BFR even for the set of BFD features (BFD Feature Set) or TRP 201 from or to which the reference signal feature (BeamFailureDetectionRS) for BFD is not provided is implemented.

[00118] Here, beamforming in NR will be described. In order to perform a multibeam PDCCH operation, NR supports a TCI state configuration, which is a higher-layer configuration for beamforming, for each CORESET. In a case where the UE 100 monitors a PDCCH seek space associated with the CORESET, the UE 100 receives the PDCCH with the CORESET based on the TCI state configuration for the CORESET. Beam information for PDCCH reception is implicitly recognized by the UE 100 through a quasi-colocation (QCL) relationship between a downlink reference signal (in particular, a CSI-RS associated with the beam) and a beam reference signal. Petition 870250048885, dated 11 / 06 / 2025, p. 38 / 74 / 53 Demodulation Signals (DMRS) of the PDCCH. The PDCCH DMRS has a quasi-colocation relationship with the downlink reference signal according to QCL-TypeA and / or QCL-TypeD. QCL-TypeA corresponds to statistical channel properties observed on the UE 100 side, such as Doppler shift, Doppler spread, average delay, and delay spread. QCL-TypeD corresponds to the received beam information on the UE 100 side. In a QCL-TypeD case, spatial parameters can be considered to be the same between the downlink reference signal and the PDCCH DMRS. In a case where the DMRS of the PDCCH is in a near-colocation relationship with the downlink reference signal of the QCL-TypeD, the PDCCH can be received by using the same spatial reception parameter that is used by UE 100 to receive the downlink reference signal in beamforming.

[00119] As illustrated in Figure 14, base station 200 can explicitly configure a QCL relationship to UE 100 via RRC signaling. UE 100 is configured with a plurality of TCI states set to CORESET to receive PDCCH. Each TCI state includes a parameter related to the downlink reference signal feature and the QCL relationship between the downlink reference signal related to QCL-TypeA and QCL-TypeD, and the DMRS port of the PDCCH. UE 100 uses only one beam to receive a PDCCH. Therefore, in a case where a plurality of TCI states are configured to CORESET, base station 200 activates, using a CE MAC activation command, one of the TCI states used to CORESET.

[00120] In one embodiment, UE 100 which performs radio communication with base station 200 which manages cell 250 which has N TRPs 201 includes communicator 110 which receives the BFD configuration list (BFDPetition 870250048885, 11 / 06 / 2025, p. 39 / 74 / 53 ConfigurationList) 520 to configure the N BFD resource sets (BFD Resource Sets) 521 originating from base station 200, and controller 120 that individually detects beam failure for each of the N BFD resource sets (BFD Resource Sets) 521 based on the BFD configuration list 520. In a case where there is a BFD resource set (BFD Resource Set) 521 that does not provide the BeamFailureDetectionRS reference signal resource, controller 120 detects beam failure for the BFD resource set (BFD Resource Set) 521 by using a predetermined reference signal resource instead of the BeamFailureDetectionRS reference signal resource.

[00121] As illustrated in Figure 15, in a case where there is a BFD feature set (BFD Feature Set) 521 (here, BFD feature set 521 No. 0) that does not provide the reference signal feature (BeamFailureDetectionRS), UE 100 (controller 120) specifies an active TCI state for PDCCH based on the CORESET No. 0 concentration index associated with BFD feature set (BFD Feature Set) 521 No. 0, and detects beam failure for BFD feature set (BFD Feature Set) 521 No. 0 by using the reference signal feature indicated by the active TCI state as the predetermined reference signal feature.For example, UE 100 (controller 120) determines the downlink reference signal (e.g., CSI-RS) indicated by the active TCI state among the TCI states (i.e., the TCI states for PDCCH) configured for the CORESET belonging to CORESET concentration index #0 as the reference signal resource (BeamFailureDetectionRS) for BFD. Thus, even in a case where the BFD resource set (BFD Resource Set) 521 does not provide the reference signal resource (BeamFailureDetectionRS), BFD can be performed using the signal from. Petition 870250048885, dated 11 / 06 / 2025, page 40 / 74 / 53, reference to the downlink indicated by the active TCI status for the PDCCH.

[00122] Figure 16 illustrates a specific example of such an operation. Note that Figure 16 illustrates an example description in the technical specification (TS 38.213) of the 3GPP physical layer.

[00123] As illustrated in Figure 16, UE 100 is considered to be configured with the BFD configuration list (bfd-ConfigurationList) 520 for the service cell's BWP. In such a case, the add / modify list (bfd-ResourcesToAddModList) provides a set q0 of periodic CSI-RS resource configuration indices for each BFD resource set (BFD Resource Set) 521 identified by the BFD resource set identifier (bfd-ResourceSetId).

[00124] In a case where set q0 is not provided by the add / modify list (bfd-ResourcesToAddModList) for the BFD resource set (BFD Resource Set) 521, UE 100 determines to include, in set q0, a periodic CSI-RS resource configuration index with the same value as the reference signal index of the adjusted downlink reference signal indicated by the TCI state of each CORESET that belongs to the CORESET concentration index associated with the BFD resource set identifier (bfdResourceSetId) used to monitor PDCCH. In a case where there are two reference signal indices in the TCI state, one reference signal index whose qcl-Type of the corresponding TCI state is set to “typeD” is included in set q0. (Coexistence with Existing Radio Link Monitoring)

[00125] Next, coexistence with existing radio link monitoring will be described in relation to figures 17 to 19. Note that figure 19 illustrates an example of description in the technical specification (TS 38.331) of the 3GPP RRC layer. Petition 870250048885, dated 11 / 06 / 2025, p. 41 / 74 / 53

[00126] As described above, existing radio link monitoring (i.e., RLF detection and beam failure detection) is performed not at the TRP 201 level, but at the cell 250 level.

[00127] In one embodiment, beam fault detection is performed not at the 250-cell level, but at the 201-TRP level. Since RLF detection at the 250-cell level in existing radio link monitoring can coexist with BFD at the 201-TRP level, RLF detection at the 250-cell level can be configured for UE 100. Conversely, since beam fault detection at the 250-cell level in existing radio link monitoring competes with beam fault detection at the 201-TRP level, beam fault detection at the 250-cell level cannot be configured for UE 100.

[00128] As illustrated in Figure 17, in step S301, base station 200 (controller 230) which manages cell 250 including the N TRPs 201 generates the RRC message including the Radio Link Monitoring configuration (RadioLinkMonitoringConfig) to configure radio link monitoring at the cell 250 level and the BFD configuration list (BFD-ConfigurationList) to configure N BFD feature sets (BFD Feature Sets). Base station 200 (communicator 210) transmits the generated RRC message to UE 100. UE 100 (communicator 110) receives the RRC message.

[00129] In step S302, UE 100 (controller 120) performs radio link monitoring for RLF detection at cell level 250 based on the radio link monitoring configuration (RadioLinkMonitoringConfig). Furthermore, UE 100 (controller 120) performs beam monitoring for beam fault detection individually for each of the N BFD feature sets based on the BFD configuration list (BFD-ConfigurationList). That is, UE 100 (controller 120) performs beam monitoring at TRP level 201. Petition 870250048885, dated 11 / 06 / 2025, page 42 / 74 / 53

[00130] When a beam fault is detected for any set of BFD features by beam monitoring based on the BFD configuration list (BFD-ConfigurationList), UE 100 (controller 120) performs processing to recover from the detected beam fault, for example, processing the BFR MAC CE transmission. Furthermore, when RLF is detected for cell 250 by radio link monitoring based on the radio link monitoring configuration (RadioLinkMonitoringConfig), UE 100 (controller 120) performs processing to recover from the detected RLF, for example, RRC restoration processing. Such two-stage fault detection and recovery can enhance communication fault resilience.

[00131] As illustrated in figures 18 and 19, in the RRC message, the radio link monitoring configuration (RadioLinkMonitoringConfig) 510 included in the BWP configuration (BWPDownlinkDedicated) 500 includes, as configuration information, a reference signal resource (RS to RLM) 511 for radio link monitoring and a purpose 512 of the reference signal resource (RS to RLM) 511. In a case where UE 100 is configured with the BFD configuration list (BFD-ConfigurationList) 520, base station 200 (controller 230) configures RLF detection (rlf) as purpose 512, instead of beam failure detection (beam failure).

[00132] Specifically, in the technical specification, there are three options: “beam failure (beam failure)”, “RLF (rlf)” and “both” as the purpose 512 of the reference signal feature (RS to RLM) 511. However, in a case where the BFD configuration list (BFD-ConfigurationList) 520 is configured for UE 100, a restriction is specified whereby only RLF (rlf) can be configured as the purpose 512 of the reference signal feature (RS to RLM) 511. Therefore, in a case where the list of Petition 870250048885, dated 11 / 06 / 2025, page 43 / 74 / 53: If BFD (BFD-ConfigurationList) configuration 520 is configured, UE 100 (controller 120) detects RLF at cell level 250 without beam fault detection based on Radio Link Monitoring configuration 510. As a result, radio link monitoring and beam fault detection at TRP level 201 can coexist appropriately.

[00133] Note that even in a case where the BFD configuration list (BFD-ConfigurationList) 520 is configured, it is also conceivable that base station 200 configures “beam failure” or “both” as the purpose 512 of the reference signal feature (RS to RLM) 511 due to an unexpected error. Therefore, in a case where the BFD configuration list (BFD-ConfigurationList) 520 is configured, and “beam failure” or “both” is configured as the purpose 512 of the reference signal feature (RS to RLM) 511, UE 100 (controller 120) may read that the purpose 512 of the reference signal feature (RS to RLM) 511 is RLF. (SpCell Beam Fault Detection and Recovery Operation)

[00134] Next, a BFD / BFR operation on an SpCell according to one embodiment will be described in relation to figures 20 to 22. Here, it is assumed that UE 100 performs radio communication with cell 250 (specifically, SpCell) including two TRPs 201 no. 0 and 201 no. 1. However, a cell 250 may include three or more TRPs 201. Furthermore, it is assumed that the BFD 521 feature set for each TRP 201 has already been configured for UE 100.

[00135] Before describing the BFD / BFR operation in a SpCell according to an embodiment, a comparative example will be described in relation to figure 20.

[00136] In step S401, UE 100 (controller 120) detects a beam fault for the BFD 521 feature set #0 associated with TRP 201 Petition 870250048885, dated 11 / 06 / 2025, p. 44 / 74 / 53 No. 0 and initiates (triggers) BFR with transmission of the CE of BFR MAC.

[00137] In step S402, UE 100 (controller 120) detects a beam fault for the BFD 521 feature set #1 associated with TRP 201 #1. In response to the beam fault detection for both BFD 521 feature sets #0 and 521 #1 (i.e., both TRPs 201 #0 and 201 #1), UE 100 (controller 120) determines to initiate the random access procedure for cell 250 (SpCell).

[00138] In step S403, UE 100 (controller 120) successfully completes BFR for the BFD 521 feature set no. 0 associated with TRP 201 no. 0, and it becomes possible to transmit and receive data to and from TRP 201 no. 0.

[00139] In step S404, UE 100 (controller 120) initiates the random access procedure for cell 250 (SpCell). UE 100 (controller 120) cannot transmit and receive data to and from cell 250 (SpCell) during the random access procedure.

[00140] In step S405, UE 100 (controller 120) cannot communicate (transmit / receive data) with cell 250 (SpCell) due to the random access procedure, although data transmission / reception with TRP 201 no. 0 is possible.

[00141] As described above, even in a case where UE 100 has a beam fault detected for TRPs 201 No. 0 and 201 No. 1, when recovery from the beam fault has occurred for TRP 201 No. 0, communication with cell 250 (SpCell) is possible. However, when the random access procedure is initiated (step S404) without considering whether recovery from the beam fault has occurred or not, data transmission / reception cannot be performed during the random access procedure and thus communication is interrupted.

[00142] Therefore, in a case where beam failure was detected for all N sets of BFD 521 features associated with the N TRPs Petition 870250048885, dated 11 / 06 / 2025, p. 45 / 74 / 53 In 201, UE 100 (controller 120), according to a modality, determines whether or not to initiate the random access procedure for cell 250 (SpCell) based on the recovery state from the beam failure. For example, UE 100 (controller 120) initiates the random access procedure for cell 250 (SpCell) only in a case where beam failure has been detected for one set of BFD 521 features out of N sets of BFD 521 features, beam failure has been detected for the other sets of BFD 521 features, and recovery from the beam failure has not occurred for any set of BFD 521 features. As a result, it is possible to prevent a state in which communication with cell 250 (SpCell) is not possible due to the random access procedure.

[00143] An example of Operation BFD / BFR 1 in a SpCell according to a modality will be described in relation to figure 21.

[00144] In step S431, UE 100 (controller 120) detects beam fault for BFD 521 feature set no. 0 associated with TRP 201 no. 0 and initiates BFR with transmission of the BFR MAC CE.

[00145] In step S432, UE 100 (controller 120) detects a beam fault for the BFD 521 feature set #1 associated with TRP 201 #1.

[00146] In step S433, UE 100 (controller 120) successfully completes BFR for the BFD 521 feature set no. 0 associated with TRP 201 no. 0, and it becomes possible to transmit and receive data to and from TRP 201 no. 0.

[00147] In step S434, UE 100 (controller 120) determines not to initiate the random access procedure for cell 250 (SpCell) in response to the successful completion of BFR for the BFD 521 feature set #0 associated with TRP 201 #0.

[00148] In stage S435, UE 100 (controller 120) can perform communication (data transmission / reception) with cell 250 (SpCell) and Petition 870250048885, dated 11 / 06 / 2025, page 46 / 74 / 53, establishes communication with cell 250 (SpCell). UE 100 (controller 120) can initiate BFR with transmission of the BFR MAC CE to the BFD 521 resource set #1 associated with TRP 201 #1.

[00149] As such, in one embodiment, UE 100 (controller 120) which has a beam fault detected for BFD 521 feature set #1 determines not to initiate the random access procedure for cell 250 (SpCell) in a case where a beam fault was detected for BFD 521 feature set #0 and recovery from beam fault occurred for BFD 521 feature set #0. As a result, it is possible to prevent a state in which communication with cell 250 (SpCell) is not possible due to the random access procedure. Furthermore, UE 100 (controller 120) may choose not to initiate the random access procedure for cell 250 (SpCell) and instead initiate the BFR procedure (i.e., BFR MAC CE transmission processing) for recovery from beam failure to the BFD 521 resource set #1. As a result, it is possible to attempt to recover communication with TRP 201 #1.

[00150] An example of BFD / BFR 2 operation in a SpCell according to one embodiment will be described in relation to figure 22.

[00151] In step S451, UE 100 (controller 120) detects beam fault for BFD 521 feature set no. 0 associated with TRP 201 no. 0 and initiates BFR with BFR MAC CE transmission.

[00152] In step S452, UE 100 (controller 120) detects beam fault for BFD 521 feature set #1 associated with TRP 201 #1 and initiates BFR with BFR MAC CE transmission.

[00153] In step S453, UE 100 (controller 120) determines that BFR for the BFD 521 resource set no. 0 associated with TRP 201 no. 0 is not completed (was unsuccessful).

[00154] In step S454, UE 100 (controller 120) determines that Petition 870250048885, dated 11 / 06 / 2025, p. 47 / 74 / 53 BFR for feature set BFD 521 #1 associated with TRP 201 #1 is not completed (was unsuccessful).

[00155] In step S455, UE 100 (controller 120) detects beam failure for all N BFD 521 feature sets, and initiates the random access procedure for cell 250 (SpCell) in response to the fact that no beam failure recovery occurred for any of the BFD 521 feature sets. (Specific Example of MAC Entity Operation in a Communication Device)

[00156] Next, a specific example of an operation of a MAC entity (i.e., a MAC layer entity) in UE 100 according to a embodiment will be described in relation to Figures 23 and 24. The MAC entity operation can be a part of the UE 100 controller 120 operation. Note that Figures 23 and 24 illustrate an example of operation in a case described in the 3GPP MAC layer technical specification (TS 38.321).

[00157] As illustrated in Figure 23, in a case where one or more BFD resource sets (BFD Resource Sets) 521 are configured for each service cell for which BFD is configured (step S501), the MAC entity performs the operations of steps S502 to S521.

[00158] In a case where the beam fault instance indication is received from a lower layer (i.e., the physical layer) for the BFD resource set (BFD Resource Set) 521 identified by the BFD resource set identifier (bfdResourceSetId) (step S502), the MAC entity performs the operations of steps S503 to S510.

[00159] In step S503, the MAC entity starts or restarts the timer (beamFailureDetectionTimerPerRS) configured for the BFD feature set (BFD Feature Set) 521 Petition 870250048885, dated 11 / 06 / 2025, page 48 / 74 / 53 identified by the BFD resource set identifier (bfdResourceSetld).

[00160] In step S504, the MAC entity increments a count value (BFI_COUNTER_BFD_RS) configured for the BFD resource set (BFD Resource Set) 521 identified by the BFD resource set identifier (bfd-ResourceSetId), that is, it adds “1”. An initial value of the count value (BFI_COUNTER_BFD_RS) is “0”.

[00161] In a case where the count value (BFI_COUNTER_BFD_RS) is greater than or equal to the maximum count value (beamFailureInstanceMaxCountPerRS) configured for the BFD resource set (BFD Resource Set) 521 identified by the BFD resource set identifier (bfd-ResourceSetId), the MAC entity performs the operations of steps S506 to S510.

[00162] Here, in a case where the service cell is a SpCell (step S506), the beam failure was detected with another BFD feature set (BFD Feature Set) 521, and recovery from the beam failure has not yet occurred by the beam recovery procedure (step S507), the MAC entity initiates the random access procedure on the SpCell for beam recovery in step S508.

[00163] On the other hand, in a case where the service cell is not an SpCell or in a case where another BFD resource set (BFD Resource Set) 521 was recovered by the beam recovery procedure (step S509), the MAC entity fires BFR for the BFD resource set (BFD Resource Set) 521 in step S510.

[00164] The MAC entity sets (resets) the count value (BFI_COUNTER_BFD_RS) to 0 in step S513 in a case where the corresponding timer (beamFailureDetectionTimerPerRS) expires. Petition 870250048885, dated 11 / 06 / 2025, p. 49 / 74 / 53 for each BFD resource set (BFD Resource Set) 521 (step S511).

[00165] On the other hand, in a case where any of the timer (beamFailureDetectionTimerPerRS), the maximum count value (beamFailureInstanceMaxCountPerRS), and the reference signal feature used for BFD (reference signal feature used for beam fault detection) associated with the BFD feature set (BFD Feature Set) 521 is reconfigured by a higher layer (i.e., the RRC layer) (step S512), the MAC entity sets (resets) the count value (BFI_COUNTER_BFD_RS) to 0 in step S513.

[00166] In a case where the service cell is an SpCell and the random access procedure for the SpCell's BFR is completed successfully (step S514), the MAC entity performs the operations of steps S515 to S517.

[00167] In step S515, the MAC entity adjusts (readjusts) the count value (BFI_COUNTER_BFD_RS) to 0.

[00168] In step S516, the MAC entity interrupts the timer (beamFailureDetectionTimerPerRS) in a case where the timer (beamFailureDetectionTimerPerRS) is configured.

[00169] In step S517, the MAC entity determines that BFR is successfully completed.

[00170] On the other hand, in a case where the service cell is an SCell and a PDCCH addressed to a C-RNTI indicating an uplink grant for new transmission was received for a HARQ process used for BFR MAC transmission including BFR information from the BFD resource set (BFD Resource Set) 521 (step S518), or in a case where the SCell is deactivated (step S519), the MAC entity performs the operations of steps S520 and S521. The BFR MAC CE Petition 870250048885, dated 11 / 06 / 2025, p. 50 / 74 / 53 includes a normal BFR MAC and a truncated BFR MAC CE.

[00171] In step S520, the MAC entity adjusts (readjusts) the count value (BFI_COUNTER_BFD_RS) to 0.

[00172] In step S521, the MAC entity determines that BFR is successfully completed and cancels all BFRs triggered for the current BFD feature set (BFD Feature Set) 521.

[00173] As illustrated in Figure 24, in a case where the MAC entity determines, in the BFR procedure, that at least one BFR has been fired for the SCell or the BFD feature set (BFD Feature Set) 521 for which the evaluation of candidate beams was performed in accordance with the requirements specified in TS 38.133 and was not canceled, the MAC entity performs the operations of steps S532 to S537.

[00174] In a case where an uplink shared channel (UL-SCH) resource is available for new transmissions and the UL-SCH resource is capable of accommodating a BFR MAC CE and its subheader due to Logical Channel Prioritization (LCP) (step S532), then in step S533, the MAC entity instructs a multiplexing and assembly procedure to generate the BFR MAC CE.

[00175] On the other hand, in a case where the UL-SCH resource can be used for new transmission and the UL-SCH resource can accommodate a Truncated BFR MAC CE and its subheader as a result of LCP (step S534), the MAC entity instructs the multiplexing and assembly procedure to generate the Truncated BFR MAC CE in step S535.

[00176] On the other hand, in a case where none of the conditions of steps S532 and S534 are met (step S536), in step S537, the MAC entity performs evaluation on the candidate beams according to the requirements specified in TS 38.133, triggers BFR, and triggers a scheduling request (SR) for BFR from the SCell for each SCell or BFD feature set (BFD Feature Set) 521 that was not canceled. Petition 870250048885, dated 11 / 06 / 2025, p. 51 / 74 / 53

[00177] The MAC entity cancels all BFRs fired to the SCell or BFD resource set (BFD Resource Set) 521 in a case where a MAC protocol data unit (PDU) is transmitted and the PDU includes a MAC BFR CE or a Truncated MAC BFR CE that includes beam information failure to the SCell or BFD resource set (BFD Resource Set) 521 (step S538).

[00178] As described above, communication device 100, which performs radio communication with base station 200 that manages cell 250, including N transmit / receive points 201, includes communicator 110, which receives a message to configure N sets of BFD resources (BFD resource sets) 521 from base station 200, and controller 120, which individually detects beam failure for each of the N sets of BFD resources (BFD resource sets) 521. Controller 120 triggers BFR for a set of BFD resources with which beam failure was detected. Communicator 110 transmits a BFR MAC CE that includes information regarding the detected beam failure or an SR to request a resource to transmit the BFR MAC CE. In a case where a MAC protocol data unit (PDU) including the BFR MAC CE is transmitted, controller 120 cancels all BFRs fired for a set of BFD resources.This makes it possible to properly perform BFR at the TRP 201 level.

[00179] In UE 100, controller 120 detects beam failure for each of the N BFD feature sets (BFD Resource Sets) 521 in response to notification of a beam failure event from the physical layer in UE 100 made a specified number of times within a specified time. As described above, each of the N BFD feature sets (BFD Resource Sets) 521 includes information to configure the timer (beamFailureDetectionTimerPerRS) that indicates the specified time and maximum count value. Petition 870250048885, dated 11 / 06 / 2025, p. 52 / 74 / 53 (beamFailureInstanceMaxCountPerRS) which indicates the specified number of times independently of other BFD feature sets.

[00180] In UE 100, in a case where a beam failure event is reported from the physical layer to a BFD feature set (BFD Feature Set) 521, controller 120 starts or resets the timer (beamFailureDetectionTimerPerRS) associated with the BFD feature set (BFD Feature Set) 521, and increments the count value (BFI_COUNTER_BFD_RS) associated with the BFD feature set (BFD Feature Set) 521. This makes it possible to properly perform BFD at the TRP 201 level.

[00181] In UE 100, controller 120 resets the count value (BFI_COUNTER_BFD_RS) associated with the BFD feature set (BFD Feature Set) 521 in a case where the timer (beamFailureDetectionTimerPerRS) associated with the BFD feature set (BFD Feature Set) 521 expires. This makes it possible to properly perform BFD at the TRP 201 level.

[00182] In UE 100, in a case where any of the timer (beamFailureDetectionTimerPerRS), the maximum count value (beamFailureInstanceMaxCountPerRS), and the reference signal resource used for BFD (reference signal resource used for beam failure detection) associated with a BFD resource set (BFD Resource Set) 521 is reconfigured by base station 200, controller 120 readjusts the count value (BFI_COUNTER_BFD_RS) associated with a BFD resource set (BFD Resource Set) 521. This makes it possible to properly perform BFD at the TRP 201 level.

[00183] In UE 100, cell 250 is a SCell, and communicator 110 receives a PDCCH indicating an uplink grant for a HARQ process used for transmitting the BFR MAC CE to a BFD resource set (BFD Resource Set) 521 after the Petition 870250048885, dated 11 / 06 / 2025, page 53 / 74 / 53 transmission of the BFR MAC CE. In response to receiving the PDCCH, controller 120 readjusts the count value (BFI_COUNTER_BFD_RS) associated with the BFD resource set (BFD Resource Set) 521, considers the BFR successful, and cancels all BFRs triggered for the BFD resource set (BFD Resource Set) 521. This makes it possible to properly perform BFD at the TRP 201 level. (Other modalities)

[00184] The operation sequence (and operation flow) in the above-described embodiment may not necessarily be executed in a time series according to the order described in the flowchart or sequence diagram. For example, the steps in the operation may be performed in a different order than the order described in the flowchart or sequence diagram, or they may be performed in parallel. Furthermore, some of the steps in the operation may be removed and additional steps may be added to the processing. Moreover, the operation sequence (and operation flow) in the above-described embodiment may be performed separately and independently, or it may be performed by combining two or more operation sequences (and operation flows). For example, some steps of one operation flow may be added to another operation flow, or some steps of one operation flow may be replaced with some steps of another operation flow.

[00185] In the above-described embodiments, base station 200 may include a plurality of units. The plurality of units may include a first unit that hosts an upper layer (upper layer) included in the protocol stack and a second unit that hosts a lower layer (lower layer) included in the protocol stack. The upper layer may include the RRC layer, the SDAP layer, and the PDCP layer, and the lower layer may include the RLC layer, the MAC layer, and the layer Petition 870250048885, dated 11 / 06 / 2025, page 54 / 74 / 53 PHY. The first unit can be a CU (Central Unit), and the second unit can be a DU (Distributed Unit). The plurality of units can include a third unit that performs processing at a lower layer of the PHY layer. The second unit can perform processing at an upper layer of the PHY layer. The third unit can be a RU (Radio Unit). Base station 200 can be one of the plurality of units, and can be connected to another unit within the plurality of units. Furthermore, base station 200 can be an IAB (Integrated Terrestrial Access and Link) donor or an IAB node.

[00186] In the above-described embodiments, a mobile communication system based on NR is described as an example of mobile communication system 1. However, mobile communication system 1 is not limited to this example. Mobile communication system 1 may be a system that conforms to a TS of either LTE or another generation (e.g., sixth generation) of the 3GPP standard. Base station 200 may be an eNB that provides user plane and evolved universal terrestrial radio access control plane (E-UTRA) protocol terminations towards UE 100 in LTE. Mobile communication system 1 may be a system that conforms to a TS defined in a standard other than the 3GPP standard.

[00187] A program to make a computer execute each processing performed by the UE 100 or base station 200 can be provided. The program can be recorded on computer-readable media. The program can be installed on the computer using the computer-readable media. Here, the computer-readable media on which the program is recorded can be non-transient recording media. Non-transient recording media is not particularly limited, but can be, for example, recording media such as a CD-ROM or a DVD-ROM. Furthermore, a circuit that executes each processing performed by the UE 100 or Petition 870250048885, dated 11 / 06 / 2025, page 55 / 74 / 53, states that base station 200 can be integrated, and at least part of UE 100 or base station 200 can be configured as a semiconductor integrated circuit (chipset, SoC).

[00188] In the above-described embodiment, “transmit” may mean performing at least one layer of processing in a protocol stack used for transmission, or it may mean physically transmitting a wireless or wired signal. Alternatively, “transmit” may mean a combination of performing at least one layer of processing and physically transmitting a wireless or wired signal. Similarly, “receive” may mean performing at least one layer of processing in a protocol stack used for reception, or it may mean physically receiving a wireless or wired signal. Alternatively, “receive” may mean a combination of performing at least one layer of processing and physically receiving a wireless or wired signal.Similarly, “acquire” can mean acquiring information from stored information, acquiring information from information received from another node, or acquiring the information by generating the information. Similarly, “includes” and “comprises” do not mean including only the listed items, but mean that the terms may include only the listed items or may include additional items beyond the listed items. Similarly, in this description, “or” does not mean exclusive OR, but means OR.

[00189] Although the present description has been presented using examples, it is understood that the present description is not limited to examples and structures. The present description also includes various modifications and alterations within an equivalent range. Furthermore, various modes and combinations, and other modes and combinations including only one element, more elements, or fewer elements, are also within the scope and idea of Petition 870250048885, dated 11 / 06 / 2025, p. 56 / 74 / 53 present description. (Supplementary Notes)

[00190] Characteristics related to the above-described modality are further described. (Supplementary Note 1)

[00191] A communication apparatus (100) that performs radio communication with a base station (200) that manages a cell (250) that includes N (N > 2) transmission / reception points (201 no. 0 and 201 no. 1), the communication apparatus comprising: a communicator (110) configured to receive a radio resource control (RRC) message from the base station (200), the RRC message including information to configure N sets of beam fault detection resources (521 No. 0 and 521 No. 1);and a controller (120) configured to individually detect beam fault for each of the N beam fault detection resource sets (521 No. 0 and 521 No. 1), wherein the controller (120) is configured to trigger beam fault recovery (BFR) for a beam fault detection resource set with which the beam fault was detected, and the controller (120) is configured to cancel all BFRs triggered for a beam fault detection resource set in a case where a Media Access Control (MAC) protocol data unit (PDU) is transmitted, the MAC protocol data unit (PDU) including a MAC BFR control element (CE) that includes information regarding the detected beam fault. (Supplementary Note 2)

[00192] The communication apparatus (100) according to supplementary note 1, in which

[00193] the communicator (110) is configured to transmit the CE of Petition 870250048885, dated 11 / 06 / 2025, p. 57 / 74 / 53 BFR MAC includes information regarding the detected beam failure or a scheduling request to request a resource to transmit the BFR MAC CE. (Supplementary Note 3)

[00194] The communication apparatus (100) according to supplementary note 1, in which

[00195] the controller (120) is configured to detect beam failure for each of the N beam failure detection feature sets (521 no. 0 and 521 no. 1) in response to notification of a beam failure event from a physical layer of the communication device (100) made a specified number of times in a specified time, and each of the N beam failure detection feature sets (521 no. 0 and 521 no. 1) includes information to configure a timer indicating the specified time and a maximum count value indicating the specified number of times independently of other beam failure detection feature sets. (Supplementary Note 4)

[00196] The communication apparatus (100) according to supplementary note 3, in which

[00197] the controller (120) is configured to start or restart the timer associated with the beam fault detection feature set and increment a count value associated with the beam fault detection feature set in a case where the beam fault event is notified from the physical layer to the beam fault detection feature set. (Supplementary Note 5)

[00198] The communication apparatus (100) according to supplementary note 4, in which

[00199] the controller (120) is configured to reset the value of Petition 870250048885, dated 11 / 06 / 2025, p. 58 / 74 / 53 count associated with a beam fault detection feature set in a case where the timer associated with the beam fault detection feature set expires. (Supplementary Note 6)

[00200] The communication apparatus (100) according to supplementary note 4 or 5, in which

[00201] the controller (120) is configured to reset the count value associated with a beam fault detection feature set in a case where any of the timer, maximum count value and reference signal feature used for beam fault detection associated with a beam fault detection feature set is reconfigured. (Supplementary Note 7)

[00202] The communication device (100) according to any of supplementary notes 4 to 6, where

[00203] the cell is a secondary cell, and the communicator (110) is configured to receive a physical downlink control channel (PDCCH) indicating uplink grant for a hybrid automatic repeat request (HARQ) process used for BFR MAC CE transmission to a beam fault detection resource set after BFR MAC CE transmission, and the controller (120) is configured to reset the count value associated with the beam fault detection resource set in response to PDCCH reception, consider the BFR successful, and cancel all BFRs fired to the beam fault detection resource set. (Supplementary Note 8)

[00204] A base station (200) that manages a cell (250) that includes N (N > 2) transmit / receive points (201 no. 0 and 201 no. 1), a Petition 870250048885, dated 11 / 06 / 2025, p. 59 / 74 / 53 base station (200) comprising:a transmitter (211) configured to transmit, to a communication device (100), a radio resource control (RRC) message that includes information to configure N sets of beam fault detection features (521 No. 0 and 521 No. 1);and a controller (230) configured to control communication with the communication device (100), wherein each of the N beam fault detection resource sets (521 No. 0 and 521 No. 1) is used for individually detecting beam faults in the communication device (100), the controller (230) is configured to control to trigger beam fault recovery (BFR) for a beam fault detection resource set with which beam faults were detected, and the controller (230) is configured to control to cancel all BFRs triggered for a beam fault detection resource set in a case where a Media Access Control (MAC) protocol data unit (PDU) is transmitted, the MAC protocol data unit (PDU) including a MAC BFR control element (CE) that includes information regarding the detected beam fault. (Supplementary Note 9)

[00205] A communication method performed by a communication device (100) that performs radio communication with a base station (200) that manages a cell (250) that includes N (N > 2) transmission / reception points (201 no. 0 and 201 no. 1), the communication method comprising the steps of: receive a radio resource control (RRC) message from the base station (200), the RRC message including information to configure N sets of beam fault detection resources (521 No. 0 and 521 No. 1); Petition 870250048885, dated 11 / 06 / 2025, p. 60 / 74 / 53 to individually detect the beam fault for each of the N sets of beam fault detection features (521 no. 0 and 521 no. 1); trigger beam fault recovery (BFR) for a beam fault detection feature set with which the beam fault was detected; and cancel all BFRs triggered for a beam fault detection feature set in a case where a Media Access Control (MAC) protocol data unit (PDU) is transmitted, the MAC protocol data unit (PDU) including a MAC BFR control element (CE) that includes information regarding the detected beam fault. Petition 870250048885, dated 11 / 06 / 2025, pp. 61 / 74

Claims

1 / 5 CLAIMS 1. A communication apparatus (100) communicating with a base station (200) that manages a cell comprising two or more transmit / receive points, the communication apparatus characterized in that it comprises: a communicator (110) configured to receive from the base station (200) a radio resource control (RRC) message including information to configure two or more beam fault detection resource sets for a downlink bandwidth portion (BWP) of a service cell; and a controller (120) configured to individually detect beam fault for each of the two or more beam fault detection resource sets, wherein the controller (120) is configured to trigger beam fault recovery (BFR) for a beam fault detection resource set for which beam fault was detected among the two or more beam fault detection resource sets,The controller (120) is configured to cancel all BFRs fired for a beam fault detection feature set for which a beam fault was detected, in a case where a Media Access Control (MAC) Protocol Data Unit (PDU) is transmitted, the MAC PDU including a MAC BFR Control Element (CE) that includes information for the detected beam fault, the RRC message includes BWP-DownlinkDedicated, which is an information element used to configure specific communication apparatus parameters of a portion of the bandwidth on the downlink, and the BWP-DownlinkDedicated includes information to configure cell-level radio link monitoring and information to configure two or more beam fault detection feature sets.

2. Communication apparatus (100) according to claim 1, characterized in that the communicator (110) is configured to transmit, to the base station (200), the BFR MAC CE or a scheduling request used to request resources for transmission of the BFR MAC CE.

3. Communication device (100) according to claim 1, characterized in that the controller (120) is configured to detect beam failure for each of two or more sets of beam failure detection features in response to notification of a beam failure instance indication from a physical layer of the communication device (100) made a specified number of times within a specified time, and each of the two or more sets of beam failure detection features includes information to configure a timer indicating the specified time and a maximum count value indicating the specified number of times independently of other sets of beam failure detection features.

4. Communication device (100) according to claim 3, characterized in that the controller (120) is configured to start or restart the timer associated with a beam fault detection feature set and increment a count value associated with the beam fault detection feature set, in a case where the beam fault instance indication is notified from the physical layer to the beam fault detection feature set.

5. Communication apparatus (100) according to claim 4, characterized in that Petition 870260057555, dated 12 / 06 / 2026, p. 17 / 26 3 / 5 the controller (120) is configured to reset the count value associated with a beam fault detection feature set in a case where the timer associated with the beam fault detection feature set expires.

6. Communication apparatus (100) according to claim 4 or 5, characterized in that the controller (120) is configured to reset the count value associated with a beam fault detection feature set in a case where any of the timer, maximum count value and a reference signal feature used for beam fault detection associated with the beam fault detection feature set is reconfigured.

7. Communication apparatus (100) according to any one of claims 4 to 6, characterized in that the communicator (110) is configured to receive, from the base station (200), a physical downlink control channel (PDCCH) indicating uplink grant for a hybrid automatic repeat request (HARQ) process used for transmitting the BFR MAC CE to a beam fault detection feature set, and the controller (120) is configured to reset the count value associated with the beam fault detection feature set, consider the BFR to have been successfully completed, and cancel all BFRs fired to the beam fault detection feature set.

8. Communication apparatus (100) according to claim 1, characterized in that the controller (120) is configured to initiate a random access procedure in a case where a BFR is triggered for all two or more reference signal resources and the BFR Petition 870260057555, dated 12 / 06 / 2026, page 18 / 26 4 / 5 is not successfully completed for any of the two or more reference signal resources.

9. A communication method performed by a communication device (100) communicating with a base station (200) that manages a cell that includes two or more transmit / receive points, the communication method characterized in that it comprises the steps of: receiving, from the base station (200), a radio resource control (RRC) message including information to configure two or more sets of beam fault detection resources for a downlink bandwidth portion (BWP) of a service cell; individually detecting beam faults for each of the two or more sets of beam fault detection resources; triggering beam fault recovery (BFR) for a set of beam fault detection resources for which beam faults were detected among the two or more sets of beam fault detection resources;Cancel all BFRs triggered for a beam fault detection resource set for which the beam fault was detected, in a case where a Media Access Control (MAC) Protocol Data Unit (PDU) is transmitted, the MAC PDU including a MAC BFR Control Element (CE) that includes information for the detected beam fault; the RRC message includes BWP-DownlinkDedicated, which is an information element used to configure specific communication apparatus parameters of a portion of the bandwidth on the downlink; and the BWP-DownlinkDedicated includes information to configure cell-level radio link monitoring and information to configure the two or more beam fault detection resource sets.

10. Communication method according to claim 9, characterized in that it further comprises the step of: transmitting to the base station (200) the BFR MAC CE or a scheduling request used to request resources for transmission of the BFR MAC CE.

11. Communication method according to claim 9 or 10, characterized in that it further comprises the step of: receiving, from the base station (200), a physical downlink control channel (PDCCH) indicating uplink grant for a hybrid automatic repeat request (HARQ) process used for transmitting the BFR MAC CE to a beam fault detection resource set, and resetting the count value associated with the beam fault detection resource set, considering that the BFR was successfully completed, and canceling all BFRs triggered to the beam fault detection resource set. Petition 870260057555, dated 12 / 06 / 2026, p. 20 / 26

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