Terminal, wireless communication method, and base station

Abstract

Appropriately perform UL transmission after BFR. A terminal involved in one embodiment of the present disclosure includes: a receiving unit that receives a response to a report of a candidate beam during a beam failure recovery (BFR) process in a secondary cell; and a control unit that, after a certain period from the last codeword received in the response, uses a spatial domain filter associated with the reported candidate beam to transmit a measurement reference signal (Sounding Reference Signal (SRS)) resource in a specific cell.

Description

Technical Field

[0001] The present disclosure relates to a terminal, a wireless communication method, and a base station in a next-generation mobile communication system. Background Art

[0002] In the Universal Mobile Telecommunications System (UMTS) network, Long Term Evolution (LTE) has been standardized to achieve even higher data rates and lower latency (Non-Patent Document 1). Furthermore, LTE-Advanced (3GPP Rel. 10-14) has been standardized to further enhance the capacity and sophistication of LTE (Third Generation Partnership Project (3GPP) Releases (Rel.) 8 and 9).

[0003] Successor systems to LTE (e.g., also known as the fifth generation mobile communication system (5G), 5G+ (plus), the sixth generation mobile communication system (6G), New Radio (NR), 3GPP Rel. 15 and later, etc.) are also being studied.

[0004] Prior art literature

[0005] Non-patent literature

[0006] Non-Patent Document 1: 3GPP TS 36.300 V8.12.0 “Evolved Universal Terrestrial Radio Access (E-UTRA) and Evolved Universal Terrestrial Radio Access Network (E-UTRAN); Overall Description; Stage 2 (Release 8)”, April 2010 Summary of the Invention

[0007] Problems to be solved by the invention

[0008] In NR, research is underway to implement a process in which user terminals (User Equipment (UE)) detect beam failure (BF) and switch to another beam (also referred to as a beam failure recovery (BFR) process, BFR, etc.).

[0009] Rel. 15 BFR stipulates that after the RA process for BFR is completed (also referred to as post-BFR, after BFR completion, etc.) and until the explicit beam is set / activated, the QCL assumptions for specific PDCCHs and the spatial relationships of specific PUCCHs are updated based on new candidate beams. This prevents situations where a failed beam continues to be used, preventing proper communication.

[0010] However, regarding the BFR for secondary cells studied in Rel.16 NR, there has been no research on updating the spatial relationship (beam) for UL channels / signals after BFR. If the spatial relationship is not properly applied, there is a concern that throughput and communication quality will be reduced.

[0011] Therefore, one of the objects of the present disclosure is to provide a terminal, a wireless communication method, and a base station that can appropriately perform UL transmission after BFR.

[0012] Means for solving problems

[0013] A terminal involved in one embodiment of the present invention comprises: a receiving unit that receives a response to a report on a candidate beam during a beam failure recovery (BFR) process of a secondary cell; and a control unit that is intended to send a measurement reference signal (Sounding Reference Signal (SRS)) resource in a specific cell using a spatial domain filter associated with the reported candidate beam after a certain period of time from the last codeword received in the response.

[0014] Effects of the Invention

[0015] According to one aspect of the present disclosure, UL transmission can be appropriately performed after BFR. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a diagram showing an example of the beam recovery process in Rel.15NR.

[0017] Figure 2 This is a diagram showing an example of the beam recovery process in Rel.16NR.

[0018] Figure 3 This is a diagram showing an example of spatial relationship update after SCell BFR involved in one embodiment.

[0019] Figure 4 This is a diagram showing an example of a schematic configuration of a wireless communication system according to an embodiment.

[0020] Figure 5 This is a diagram showing an example of the configuration of a base station according to one embodiment.

[0021] Figure 6 This is a diagram showing an example of the configuration of a user terminal according to an embodiment.

[0022] Figure 7 This is a diagram showing an example of the hardware configuration of a base station and a user terminal according to one embodiment. DETAILED DESCRIPTION

[0023] (Beam Failure Recovery)

[0024] In NR, research is underway to utilize beamforming for communication. For example, UEs and base stations (e.g., gNodeBs (gNBs)) can use beams for signal transmission (also known as transmit beams, Tx beams, etc.) and beams for signal reception (also known as receive beams, Rx beams, etc.).

[0025] When beamforming is used, radio link quality deteriorates due to the potential for interference from obstacles. This deterioration in radio link quality can lead to frequent radio link failures (RLFs). RLFs require cell reconnection, so frequent RLFs can lead to reduced system throughput.

[0026] In NR, to suppress RLF, research is underway to implement a procedure for switching to another beam when the quality of a specific beam deteriorates (also known as beam recovery (BR), beam failure recovery (BFR), L1 / L2 (Layer 1 / Layer 2) beam recovery, etc.). The BFR procedure can also be abbreviated as BFR.

[0027] In addition, beam failure (BF) in the present disclosure may also be referred to as link failure or radio link failure (RLF).

[0028] Figure 1 This is a diagram showing an example of the beam recovery process in Rel.15NR. The number of beams is an example and is not limited to this. Figure 1 In the initial state (step S101), the UE performs measurement based on the reference signal (RS) resources transmitted using two beams.

[0029] The RS may be at least one of a synchronization signal block (SSB) and a channel state information RS (CSI-RS). In addition, the SSB may also be referred to as an SS / PBCH (Physical Broadcast Channel) block.

[0030] The RS may be at least one of a primary synchronization signal (PSS), a secondary synchronization signal (SSS), a mobility reference signal (MRS), a signal included in an SSB, an SSB, a CSI-RS, a demodulation reference signal (DMRS), a beam-specific signal, or a signal formed by extending or modifying these. The RS measured in step S101 may also be referred to as an RS for beam failure detection (Beam Failure Detection RS: BFD-RS).

[0031] In step S102, the UE cannot detect the BFD-RS (or the reception quality of the RS deteriorates) because the radio waves from the base station are blocked. Such blocking may occur due to, for example, obstacles, fading, interference, etc. between the UE and the base station.

[0032] If certain conditions are met, the UE detects beam failure. For example, the UE may detect beam failure when the block error rate (BLER) for all configured BFD-RS (BFD-RS resource configuration) is less than a threshold. If beam failure is detected, the UE's lower (lower) layers (physical (PHY) layer) may also notify (indicate) the higher (upper) layers (MAC layer) of the beam failure instance.

[0033] In addition, the criterion (standard) for judgment is not limited to BLER, but can also be the reference signal received power in the physical layer (Layer 1 Reference Signal Received Power (L1-RSRP)). In addition, instead of RS measurement or in addition to RS measurement, beam failure detection can also be implemented based on downlink control channels (Physical Downlink Control Channel (PDCCH)). It can also be expected that the BFD-RS and the DMRS of the PDCCH monitored by the UE are quasi-co-located (Quasi-Co-Location: QCL).

[0034] Here, QCL is an indicator that indicates the statistical properties of a channel. For example, the fact that a certain signal / channel is in a QCL relationship with other signals / channels can also mean that it can be assumed that at least one of the Doppler shift, Doppler spread, average delay, delay spread, and spatial parameters (e.g., spatial receive filter / parameters and spatial transmit filter / parameters) is the same among these different signals / channels (at least one of these is QCL).

[0035] In addition, the spatial reception parameter may also correspond to the UE's receive beam (e.g., receive analog beam), and the beam may also be determined based on spatial QCL. The QCL (or at least one element of QCL) in this disclosure may also be replaced with spatial QCL (sQCL).

[0036] Information related to BFD-RS (e.g., RS index, resources, number, number of ports, precoding, etc.) and information related to beam failure detection (BFD) (e.g., the aforementioned thresholds) can also be set (notified) to the UE using higher-layer signaling. Information related to BFD-RS can also be referred to as information related to BFR resources.

[0037] In the present disclosure, the higher layer signaling may be, for example, any one of Radio Resource Control (RRC) signaling, Medium Access Control (MAC) signaling, broadcast information, etc., or a combination thereof.

[0038] MAC signaling may use, for example, MAC Control Element (CE) and MAC Protocol Data Unit (PDU). Broadcast information may include, for example, Master Information Block (MIB), System Information Block (SIB), minimum system information (Remaining Minimum System Information (RMSI)), and Other System Information (OSI).

[0039] The MAC layer of the UE may also start a specific timer (also referred to as a beam failure detection timer) when receiving a beam failure instance notification from the PHY layer of the UE. The MAC layer of the UE may also trigger BFR (e.g., start any of the random access procedures described below) after receiving a certain number of beam failure instance notifications (e.g., beamFailureInstanceMaxCount set by RRC) before the timer expires.

[0040] In the absence of notification from the UE (for example, the time without notification exceeds a specific time), or when a specific signal (beam recovery request in step S104) is received from the UE, the base station may also determine that the UE has detected a beam failure.

[0041] In step S103, for beam recovery, the UE starts searching for a new candidate beam (new candidate beam) for communication. The UE can also select a new candidate beam corresponding to a specific RS by measuring the RS. The RS measured in step S103 may also be referred to as an RS for new candidate beam identification (New Candidate Beam Identification RS (NCBI-RS)), CBI-RS, candidate beam RS (Candidate Beam RS (CB-RS)), etc. NCBI-RS may be the same as or different from BFD-RS. In addition, the new candidate beam may also be referred to as a new candidate beam, a candidate beam, or a new beam.

[0042] The UE may also determine the beam corresponding to the RS that meets specific conditions as a new candidate beam. For example, the UE may also determine the new candidate beam based on the RS whose L1-RSRP exceeds the threshold in the set NCBI-RS. In addition, the judgment criterion (standard) is not limited to L1-RSRP. It may also be determined using any at least one of L1-RSRP, L1-RSRQ, and L1-SINR (signal to noise and interference power ratio). The L1-RSRP associated with SSB may also be referred to as SS-RSRP. The L1-RSRP associated with CSI-RS may also be referred to as CSI-RSRP. Similarly, the L1-RSRQ associated with SSB may also be referred to as SS-RSRQ. The L1-RSRQ associated with CSI-RS may also be referred to as CSI-RSRQ. In addition, similarly, the L1-SINR associated with SSB may also be referred to as SS-SINR. The L1-SINR associated with CSI-RS may also be referred to as CSI-SINR.

[0043] Information related to NCBI-RS (e.g., RS resources, quantity, number of ports, precoding, etc.) and information related to new candidate beam identification (NCBI) (e.g., the aforementioned thresholds) can also be set (notified) to the UE using higher-layer signaling. Information related to NCBI-RS can also be obtained based on information related to BFD-RS. Information related to NCBI-RS can also be referred to as information related to NCBI resources.

[0044] In addition, BFD-RS, NCBI-RS, etc. may be replaced with a Radio Link Monitoring Reference Signal (RLM-RS: Radio Link Monitoring RS).

[0045] In step S104, the UE that has determined the new candidate beam transmits a beam restoration request (Beam Failure Recovery request (BFRQ)). The beam restoration request may also be referred to as a beam restoration request signal, a beam failure recovery request signal, or the like.

[0046] BFRQ can also be sent using a random access channel (Physical Random Access Channel (PRACH)), for example. BFRQ can also include information about the new candidate beam determined in step S103. The resources used for BFRQ can also be associated with the new candidate beam. Beam information can also be notified using a beam index (Beam Index: BI), a port index of a specific reference signal, a resource index (e.g., CSI-RS Resource Indicator (CSI-RS Resource Indicator: CRI), an SSB Resource Indicator (SSBRI)), etc.

[0047] In Rel.15NR, BFR based on contention-based random access (Contention-based Random Access (CFRA)) process, namely CB-BFR (Contention-Based BFR) and BFR based on non-contention-based random access process (Contention-Free Random Access (CBRA)) process, namely CF-BFR (Contention-Free BFR)). In CB-BFR and CF-BFR, the UE can also use PRACH resources to send the preamble (also called RA preamble, random access channel (Physical Random Access Channel: PRACH), RACH preamble, etc.) as BFRQ.

[0048] In addition, CF-BFR can also be called CFRA BFR, and CB-BFR can also be called CBRA BFR.

[0049] In step S105, the base station that detects the BFRQ sends a response signal (also referred to as a BFR response, gNB response, etc.) to the BFRQ from the UE. The response signal may also include reconstruction information for one or more beams (e.g., structure information of DL-RS resources).

[0050] This response signal may also be transmitted, for example, in the UE-common search space of the PDCCH. This response signal may also be notified using the PDCCH (DCI) with a cyclic redundancy check (CRC) scrambled with the UE's identifier (e.g., the Cell Radio Network Temporary Identifier (C-RNTI)). The UE may also determine at least one of the transmit and receive beams to use based on the beam reconfiguration information.

[0051] The UE may monitor the response signal based on at least one of a BFR control resource set (CORESET) and a BFR search space set. For example, the UE may detect DCI with a CRC scrambled using the C-RNTI in a BFR search space within a separately configured CORESET.

[0052] Regarding CB-BFR, when the UE receives the PDCCH corresponding to the C-RNTI related to itself, it may be determined that contention resolution has succeeded.

[0053] Regarding the process of step S105, a period may be set for the UE to monitor a response (acknowledgement) from a base station (e.g., a gNB) to a BFRQ. This period may also be referred to as, for example, a gNB response window, a gNB window, a beam recovery request response window, or a BFRQ acknowledgement window. If no gNB response is detected within this window, the UE may retransmit the BFRQ.

[0054] In step S106, the UE may also send a message to the base station indicating that the beam reconfiguration is complete. This message may be sent, for example, via the PUCCH or the PUSCH.

[0055] In step S106 , the UE may receive RRC signaling indicating the configuration of the Transmission Configuration Indication state (TCI state) used in the PDCCH, or may receive a MAC CE indicating activation of the configuration.

[0056] Beam recovery success (BR success) may also indicate, for example, reaching step S106. On the other hand, beam recovery failure (BR failure) may also correspond to, for example, reaching a specific number of BFRQ transmissions or the expiration of the beam failure recovery timer (Beam-failure-recovery-Timer).

[0057] The numbers of these steps are for illustrative purposes only, and multiple steps may be combined or their order may be reversed. Furthermore, whether or not to implement BFR may be configured in the UE using higher layer signaling.

[0058] (BFR based on MAC CE)

[0059] However, in future wireless communication systems (for example, after Rel. 16), research is underway to use the uplink control channel (PUCCH) and MAC control information (MAC CE) to notify the occurrence of beam failure, report information related to the cell (or CC) where the beam failure was detected, and report information related to new candidate beams.

[0060] For example, the UE considers the following situation: after detecting a beam failure, the UE uses one or more steps (for example, two steps) to report the occurrence of the beam failure, information related to the cell where the beam failure was detected, and information related to the new candidate beam (refer to Figure 2 ). In addition, the reporting operation is not limited to two steps.

[0061] Compared to PRACH, the uplink control channel can more flexibly set resources in the time domain. Therefore, as a channel used for BFRQ transmission, the uplink control channel (PUCCH) is effective. In addition, compared to PRACH, the MAC CE (PUSCH) can more flexibly set resources in the time domain. Therefore, as a channel used for BFRQ transmission, the MAC CE (PUSCH) is effective.

[0062] Utilized Figure 2 The BFR reported by the MAC CE shown can be called MAC CE based BFR (MACCE based BFR), two-step BFR, Rel.16BFR, etc., and can also be called SCell BFR based on the envisioned purpose of recovering beam failure of the secondary cell (SCell).

[0063] In addition, the above Figure 1The BFR can also be called PRACH-based BFR, PRACH-based Primary Cell (PCell) BFR, Rel.15 BFR, etc.

[0064] exist Figure 2 In the first step (or, step 1), the UE first detects the occurrence of beam failure in a certain cell (e.g., SCell). This detection can also be performed using the same method as Rel.15 BFR. In the first step (or, step 1), the UE uses the uplink control channel (PUCCH) to notify the occurrence of beam failure.

[0065] The UE that detects a beam failure searches for a new candidate beam in the cell. The new candidate beam may also be a beam corresponding to an RS that satisfies the specific conditions. The UE is configured to use MAC control information (e.g., a MAC CE or a MAC PDU including a MAC CE) in the second step (or step 2) to report at least one of information related to the cell in which the beam failure was detected and information related to the new candidate beam.

[0066] In the following description, the information sent in the first step is also referred to as first information, and the information sent in the second step is also referred to as second information.

[0067] The PUCCH in the first step can also use the same method as the scheduling request (SR) transmission. For example, the UE can also use the SR to transmit the first information notifying the occurrence of beam failure during the BFR process. The SR used to notify the occurrence of beam failure can also be called BFR SR, SCell BFR SR, SCell dedicated SR (dedicated SR for SCell), dedicated SR (dedicated SR), Link Recovery Request (LRR), etc.

[0068] The MAC CE (or MAC PDU) in the second step may also be transmitted using uplink resources. For example, the UE may transmit the MAC CE using uplink resources allocated from the base station via the PUCCH (e.g., dedicated SR-like PUCCH) in the first step. This MAC CE may also be referred to as a BFR MAC CE, a BFR MAC CE, or the like.

[0069] The uplink resources may also be replaced by resources (UL-SCH resources) used for a theoretical uplink channel (e.g., an uplink shared channel (UL-SCH))) or resources used for a physical uplink channel (e.g., a physical uplink shared channel (Physical Uplink Shared Channel)).

[0070] The PUCCH format used in the first step may be, for example, PUCCH format (PF) 0 or 1. Furthermore, PUCCH transmission in the first step may be performed via a specific cell (e.g., a primary cell (PCell), a primary / secondary cell (PSCell), or another SCell where a BF is not detected). PF0 may also consist of 1 or 2 symbols. On the other hand, PF1 may also consist of 4 or more symbols.

[0071] The PUCCH resources for BFR in the SCells in the first step may also be commonly configured for all SCells included in a specific group (e.g., the same cell group). Furthermore, the UE may detect beam failure and, if it receives an UL grant in a cell capable of transmitting a MAC CE for BFR before transmitting the PUCCH (or SR) in the first step, not transmit the PUCCH in the first step.

[0072] The transmission of MAC CE (PUSCH transmission) in the second step may also be performed through the above-mentioned specific cell (eg, PCell, PSCell, other SCells).

[0073] Even if the UE detects a beam failure, if it cannot determine a new candidate beam, the MAC CE in the second step may include information about the cell where the beam failure was detected, rather than the index of the new candidate beam. The inability to determine a new candidate beam may also occur, for example, when there is no reference signal with a received power (RSRP) greater than a specific value.

[0074] After sending the BFR MAC CE, the UE receives a BFR response. The BFR response may also be equivalent to a DCI that schedules a PUSCH transmission with the same HARQ process number as that used in the transmission of the first PUSCH that transmitted the BFR MAC CE and has a switched New Data Indicator (NDI) field value (in other words, scheduling a new transmission).

[0075] Rel. 15's PRACH-based BFR stipulates that between the completion of the RA procedure for BFR (also referred to as post-BFR, post-BFR completion, etc.) and the configuration / activation of an explicit beam, the QCL assumptions for a specific PDCCH and the spatial relationship of a specific PUCCH are updated based on new candidate beams. This prevents situations where a failed beam continues to be used, preventing proper communication.

[0076] However, research has not yet been conducted on updating the spatial relationships (beams) used for UL channels and signals after SCell BFR. For example, it is unclear how to update the spatial relationships of measurement reference signals (Sounding Reference Signals (SRS)). If spatial relationships are not properly applied, there is a concern that throughput and communication quality may be reduced.

[0077] Therefore, the inventors of the present invention have conceived a method for appropriately performing UL transmission after BFR.

[0078] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. The wireless communication methods according to the various embodiments may be applied individually or in combination.

[0079] In the present disclosure, “A / B” and “at least one of A and B” may also be replaced with each other.

[0080] (Wireless Communication Method)

[0081] In one embodiment of the present disclosure, with respect to the SCell(s) in which beam failure (BF) is detected, the UE may also implement at least one of the following operations (1)-(3) after 28 codewords from the last codeword received from the PDCCH in the DCI format with the switched New Data Indicator (NDI) field value, after scheduling the PUSCH transmission with the same HARQ process number as the HARQ process number used in the transmission of the first PUSCH for transmitting the BFR MAC CE.

[0082] (1) Use and about index q new The same QCL parameters are used for the antenna ports, and the PDCCH in all CORESETs of the SCell(s) indicated by the MAC CE are monitored.

[0083] (2) Use and about index q newThe same spatial domain filter is used for receiving the periodic CSI-RS or SSB, and q is applied using the mathematical formula used in determining the transmit power of the PUCCH (Subclause 7.2.1 of TS 38.213). u =0,q d =q new , and the transmission power determined by 1=0, PUCCH is transmitted in PUCCH-SCell (wherein the three conditions are met: PUCCH spatial relationship information (PUCCH-SpatialRelationInfo) for the PUCCH is provided to the UE, LRR is not transmitted through the PUCCH-SCell, and the PUCCH-SCell is included in the above-mentioned SCell(s) indicated by the above-mentioned MAC CE).

[0084] In addition, under normal circumstances, q u It can also be a PUCCH P0 ID (p0-PUCCH-Id) indicating PUCCH P0 (P0-PUCCH) within the PUCCH P0 set (p0-Set). l It can also be called an index of the power control adjustment state, a closed-loop index, etc. d It may also be an index of a path loss reference RS (for example, set by PUCCH-PathlossReferenceRS).

[0085] In addition, q new It can also be the index related to the new candidate beam (e.g., SSB / CSI-RS) reported by the UE to the network during the BFR process.

[0086] (3) Use and about index q new The same spatial domain filter is used for receiving the periodic CSI-RS or SSB, and q is applied to the mathematical formula used in determining the transmission power of the SRS (Subclause 7.3.1 of TS 38.213). d =q new , 1=0, and transmits aperiodic SRS (A-SRS) resources in a specific cell (where the condition that spatial relationship information (spatialRelationInfo) for the A-SRS resources is provided to the UE is met).

[0087] The specific cell mentioned in (3) above may also be a cell corresponding to at least one of the following:

[0088] Index q newSCell (in other words, receiving the SCell with index q new Corresponding CSI-RS, SSB cell),

[0089] SCell reported as BF detected in the above-mentioned BFR MAC CE,

[0090] All SCells for which SCell BFR (or SCell beam failure detection) is set,

[0091] All SCells included in the PUCCH group (PUCCH cell group) to which the PUCCH-SCell in (2) above belongs,

[0092] All SCells that have been set,

[0093] All activated SCells,

[0094] All SCells configured / activated within the intra-frequency band (or within the band) to which the SCell to which SCell BFR is implemented belongs.

[0095] Regarding PUCCH, the only SCell that can transmit PUCCH in SCells using SCell BFR is the PUCCH-SCell. On the other hand, SRS can be transmitted in any SCell, so it is preferable to specify a specific cell in this way.

[0096] The A-SRS resource in (3) above may also be an A-SRS resource included in an SRS resource set whose usage in a higher layer parameter is set to a specific usage. The specific usage may be, for example, at least one of codebook, non-codebook, antenna switching, and beam management.

[0097] In the case where the A-SRS resource in (3) above corresponds to the SRS for codebook / non-codebook purposes, the UE can appropriately update the beam (spatial relationship) of the PUSCH of the SCell in which the BF is detected to q new This is because the codebook / non-codebook-purpose SRS can also be used to determine the precoder for codebook-based or non-codebook-based PUSCH transmission based on the SRS Resource Indicator (SRI).

[0098] The UE may also assume that the spatial relationship of A-SRS resources corresponding to a use other than the specific use is explicitly updated using MAC CE.

[0099] In addition, the subcarrier spacing (SCS) setting for the above-mentioned 28 code elements can also be equivalent to the minimum SCS setting between the SCS setting for activating the downlink bandwidth part (DL BWP) for the above-mentioned PDCCH reception and the SCS setting for activating the DL BWP for the SCell(s) that detects the above-mentioned beam failure.

[0100] The PUCCH / SRS transmission in (2) and (3) above may also refer to the use of the PUCCH / SRS for receiving and indexing q. new The same spatial domain filter as the spatial domain reception filter for the corresponding reference signal (e.g., SSB, CSI-RS) is transmitted (transmission to which the spatial domain filter corresponding to the new candidate beam is applied). According to (2) and (3) above, the spatial relationship of the PUCCH / SRS can be updated to the spatial relationship corresponding to the new candidate beam 28 symbols later from the BFR response.

[0101] In the above (2), “PUCCH spatial relationship information (PUCCH-SpatialRelationInfo) for the PUCCH is provided to the UE” may be replaced with “the default spatial relationship is not applied to the PUCCH”.

[0102] The above (3) "spatial relationship information (spatialRelationInfo) for the A-SRS resource is provided to the UE" can also be replaced with "no default spatial relationship is applied to the A-SRS resource".

[0103] Figure 3 This figure illustrates an example of a spatial relationship update after SCell BFR according to one embodiment. In this example, the UE transmits and receives SCell BFR to the PCell for BFR related to a BFR detected in a particular SCell. Furthermore, the base station forming the PCell can be different from or the same as the base station forming the SCell.

[0104] In this example, after 28 symbols from the last symbol received from the PDCCH of the BFR response (DCI format), the UE may also assume that the beam for PUCCH / SRS transmission is the same as the new candidate beam (new beam) reported in the MAC CE (applying the same as the index q in PUCCH / SRS transmission). newThe same spatial domain filter is used to receive periodic CSI-RS or SSB.

[0105] In addition, the UE may assume that the operations (1) to (3) above are not performed until 28 symbols have passed since the last symbol received from the PDCCH of the BFR response (DCI format).

[0106] According to one embodiment of the present disclosure described above, the beam restored by SCell BFR can be appropriately used for subsequent PUCCH / SRS transmission.

[0107] <Other>

[0108] The "28 symbols" in the above embodiment may be replaced with "X symbols" (or a specific number of symbols). This X (specific number) may be predetermined by a specification, set by higher-layer signaling, or determined based on UE capabilities (e.g., UE capabilities related to BFR).

[0109] Furthermore, the phrase “after symbol 28” in the present disclosure may be replaced with “during a certain period after symbol 28.” This certain period may be, for example, a period until a spatial relationship is set / activated for PUCCH / SRS.

[0110] Furthermore, the above-described embodiment can also be applied to a UE for which specific parameters are configured via RRC. For example, the specific parameters may be parameters that enable Rel. 16 BFR (or SCell BFR).

[0111] Furthermore, the above embodiment may also be applied to a UE that reports specific capability information to the network. This capability information may, for example, be capabilities related to QCL assumptions / spatial relationships after SCell BFR. A UE that has reported this capability information may also, when implementing SCell BFR, perform at least one of the operations (1)-(3) above 28 symbols after the last symbol received in the BFR response.

[0112] In addition, the "A-SRS resources" in the above embodiment may also be replaced by at least one of periodic SRS (P-SRS) resources, semi-persistent SRS (SP-SRS) resources, and A-SRS resources.

[0113] In addition, the SCell in each of the above embodiments may be replaced by at least one of a special cell (SpCell) and an SCell. The SpCell may be interchangeable with the PCell / PSCell, or may refer to a cell other than the PCell / PSCell.

[0114] (Wireless Communication System)

[0115] The following describes a configuration of a wireless communication system according to an embodiment of the present disclosure. In this wireless communication system, communication is performed using any one of the wireless communication methods according to the above-described embodiments of the present disclosure or a combination thereof.

[0116] Figure 4 This figure shows an example of a schematic configuration of a wireless communication system according to one embodiment. The wireless communication system 1 may also be a system that implements communication using Long Term Evolution (LTE) standardized by the Third Generation Partnership Project (3GPP), the fifth generation mobile communication system New Radio (5G NR), or the like.

[0117] In addition, the wireless communication system 1 can also support dual connectivity (Multi-RAT Dual Connectivity (MR-DC)) between multiple radio access technologies (Radio Access Technology (RAT)). MR-DC can also include dual connectivity between LTE (Evolved Universal Terrestrial Radio Access (E-UTRA)) and NR (E-UTRA-NR Dual Connectivity (EN-DC)), dual connectivity between NR and LTE (NR-E-UTRA Dual Connectivity (NR-E-UTRA Dual Connectivity (NE-DC)), etc.

[0118] In EN-DC, the LTE (E-UTRA) base station (eNB) is the master node (MN), and the NR base station (gNB) is the secondary node (SN). In NE-DC, the NR base station (gNB) is the MN, and the LTE (E-UTRA) base station (eNB) is the SN.

[0119] The wireless communication system 1 can also support dual connectivity between multiple base stations within the same RAT (for example, dual connectivity (NR-NR Dual Connectivity (NN-DC)) where both MN and SN are NR base stations (gNB)).

[0120] The wireless communication system 1 may also include a base station 11 that forms a macrocell C1 with relatively wide coverage, and base stations 12 (12a-12c) that are deployed within the macrocell C1 and form small cells C2 that are narrower than the macrocell C1. User terminals 20 may also be located within at least one of the cells. The configuration and number of cells and user terminals 20 are not limited to those shown in the figure. Hereinafter, when not distinguishing between base stations 11 and 12, they are collectively referred to as base stations 10.

[0121] The user terminal 20 may be connected to at least one of the multiple base stations 10. The user terminal 20 may utilize at least one of carrier aggregation (CA) using multiple component carriers (CCs) and dual connectivity (DC).

[0122] Each CC may also be included in at least one of the first frequency band (Frequency Range 1 (FR1)) and the second frequency band (Frequency Range 2 (FR2)). The macro cell C1 may also be included in FR1, and the small cell C2 may also be included in FR2. For example, FR1 may be a frequency band below 6 GHz (below 6 GHz (sub-6 GHz)), and FR2 may be a frequency band higher than 24 GHz (above-24 GHz). In addition, the frequency bands and definitions of FR1 and FR2 are not limited to these. For example, FR1 may also be equivalent to a frequency band higher than FR2.

[0123] Furthermore, the user terminal 20 may perform communication using at least one of time division duplex (TDD) and frequency division duplex (FDD) in each CC.

[0124] Multiple base stations 10 can also be connected by wired (for example, optical fiber based on Common Public Radio Interface (CPRI)), X2 interface, etc.) or wireless (for example, NR communication). For example, when NR communication is used as a backhaul between base stations 11 and 12, the base station 11 equivalent to the upper station can also be called an integrated access backhaul (IAB) donor, and the base station 12 equivalent to the relay station (relay) can also be called an IAB node.

[0125] The base station 10 may also be connected to the core network 30 via other base stations 10 or directly. The core network 30 may also include, for example, at least one of an Evolved Packet Core (EPC), a 5G Core Network (5GCN), and a Next Generation Core (NGC).

[0126] The user terminal 20 may also be a terminal that supports at least one of communication methods such as LTE, LTE-A, and 5G.

[0127] In the wireless communication system 1, a radio access scheme based on orthogonal frequency division multiplexing (OFDM) may be used. For example, in at least one of the downlink (DL) and uplink (UL), cyclic prefix OFDM (CP-OFDM), discrete Fourier transform spread OFDM (DFT-s-OFDM), orthogonal frequency division multiple access (OFDMA), or single carrier frequency division multiple access (SC-FDMA) may be used.

[0128] The radio access scheme may also be referred to as a waveform. In addition, in the wireless communication system 1, other radio access schemes (eg, other single-carrier transmission schemes, other multi-carrier transmission schemes) may be used as the UL and DL radio access schemes.

[0129] As downlink channels, the wireless communication system 1 may use a downlink shared channel (Physical Downlink Shared Channel (PDSCH)) shared by each user terminal 20), a broadcast channel (Physical Broadcast Channel (PBCH)), a downlink control channel (Physical Downlink Control Channel (PDCCH)), etc.

[0130] In addition, as uplink channels, the wireless communication system 1 can also use an uplink shared channel (Physical Uplink Shared Channel (PUSCH)) shared by each user terminal 20), an uplink control channel (Physical Uplink Control Channel (PUCCH)), a random access channel (Physical Random Access Channel (PRACH)), etc.

[0131] User data, higher-layer control information, and system information blocks (SIBs) are transmitted via the PDSCH. User data, higher-layer control information, and the like can also be transmitted via the PUSCH. Furthermore, the Master Information Block (MIB) can also be transmitted via the PBCH.

[0132] The lower layer control information may also be transmitted via the PDCCH. The lower layer control information may include, for example, downlink control information (Downlink Control Information (DCI)) including scheduling information for at least one of the PDSCH and the PUSCH.

[0133] In addition, the DCI that schedules the PDSCH may also be referred to as DL allocation, DL DCI, etc., and the DCI that schedules the PUSCH may also be referred to as UL grant, UL DCI, etc. In addition, the PDSCH may also be replaced by DL data, and the PUSCH may also be replaced by UL data.

[0134] In PDCCH detection, a control resource set (CORESET) and a search space can also be used. A CORESET corresponds to the resources for searching for DCI. A search space corresponds to the search area and search method for PDCCH candidates. A CORESET can also be associated with one or more search spaces. The UE can also monitor the CORESET associated with a search space based on the search space settings.

[0135] A search space may also correspond to PDCCH candidates corresponding to one or more aggregation levels. One or more search spaces may also be referred to as a search space set. In addition, the terms "search space," "search space set," "search space setting," "search space set setting," "CORESET," and "CORESET setting" in this disclosure may be used interchangeably.

[0136] Uplink control information (uplink control information (UCI)) including at least one of channel state information (CSI), delivery confirmation information (e.g., also known as hybrid automatic repeat request confirmation (HARQ-ACK), ACK / NACK, etc.), and scheduling request (SR) can also be transmitted via the PUCCH. The random access preamble used to establish a connection with a cell can also be transmitted via the PRACH.

[0137] In the present disclosure, downlink, uplink, etc. may be expressed without the word "link." Furthermore, various channels may be expressed without the word "physical" at the beginning.

[0138] In the wireless communication system 1, a synchronization signal (Synchronization Signal (SS)), a downlink reference signal (Downlink Reference Signal (DL-RS)), etc. can also be transmitted. As DL-RS, in the wireless communication system 1, a cell-specific reference signal (Cell-specific Reference Signal (CRS)), a channel state information reference signal (Channel State Information Reference Signal (CSI-RS)), a demodulation reference signal (DeModulation Reference Signal (DMRS)), a positioning reference signal (Positioning Reference Signal (PRS)), a phase tracking reference signal (Phase Tracking Reference Signal (PTRS)), etc. can also be transmitted.

[0139] For example, a synchronization signal may be at least one of a primary synchronization signal (PSS) and a secondary synchronization signal (SSS). A signal block containing SSs (PSS, SSS) and PBCHs (and DMRS for PBCHs) may also be referred to as an SS / PBCH block or an SS block (SSB). Furthermore, SSs and SSBs may also be referred to as reference signals.

[0140] In addition, in the wireless communication system 1, as an uplink reference signal (Uplink Reference Signal (UL-RS)), a measurement reference signal (Sounding Reference Signal (SRS)), a demodulation reference signal (DMRS), etc. can also be transmitted. In addition, DMRS can also be called a user terminal specific reference signal (UE-specific Reference Signal).

[0141] (Base Station)

[0142] Figure 5This figure shows an example of the configuration of a base station according to one embodiment. The base station 10 includes a control unit 110, a transmitting / receiving unit 120, a transmitting / receiving antenna 130, and a transmission path interface (transmission line interface) 140. Furthermore, more than one of each of the control unit 110, the transmitting / receiving unit 120, the transmitting / receiving antenna 130, and the transmission path interface 140 may be provided.

[0143] In addition, in this example, the functional blocks of the characteristic parts of this embodiment are mainly shown, and it is also assumed that the base station 10 also has other functional blocks required for wireless communication. Part of the processing of each unit described below may also be omitted.

[0144] The control unit 110 controls the entire base station 10. The control unit 110 can be composed of a controller, a control circuit, and the like that are described based on common knowledge in the technical field to which this disclosure relates.

[0145] The control unit 110 may also control signal generation, scheduling (e.g., resource allocation, mapping), etc. It may also control transmission and reception, measurement, etc., using the transmission and reception unit 120, the transmission and reception antennas 130, and the transmission path interface 140. The control unit 110 may also generate data, control information, sequences, etc. to be transmitted as signals, and forward them to the transmission and reception unit 120. The control unit 110 may also perform call processing (setting up, releasing, etc.) of communication channels, manage the status of the base station 10, manage radio resources, etc.

[0146] The transceiver unit 120 may also include a baseband unit 121, a radio frequency (RF) unit 122, and a measurement unit 123. The baseband unit 121 may also include a transmission processing unit 1211 and a reception processing unit 1212. The transceiver unit 120 may include a transmitter / receiver, an RF circuit, a baseband circuit, a filter, a phase shifter (phase shifter), a measurement circuit, a transceiver circuit, and the like, which are described based on common knowledge in the technical fields involved in this disclosure.

[0147] The transmitting and receiving unit 120 may be configured as an integrated transmitting and receiving unit or may be configured as a transmitting unit and a receiving unit. The transmitting unit may also be configured as a transmitting processing unit 1211 and an RF unit 122. The receiving unit may also be configured as a receiving processing unit 1212, an RF unit 122, and a measuring unit 123.

[0148] The transmitting and receiving antenna 130 can be formed of an antenna described based on common knowledge in the technical field to which this disclosure relates, such as an array antenna.

[0149] The transmitting and receiving unit 120 may also transmit the aforementioned downlink channel, synchronization signal, downlink reference signal, etc. The transmitting and receiving unit 120 may also receive the aforementioned uplink channel, uplink reference signal, etc.

[0150] The transmitting and receiving unit 120 may also use digital beamforming (eg, precoding), analog beamforming (eg, phase rotation), etc. to form at least one of a transmit beam and a receive beam.

[0151] The sending and receiving unit 120 (sending processing unit 1211) can also perform processing on the Packet Data Convergence Protocol (PDCP) layer, the Radio Link Control (RLC) layer (for example, RLC retransmission control), the Medium Access Control (MAC) layer (for example, HARQ retransmission control), etc. on the data and control information obtained from the control unit 110 to generate a bit string to be sent.

[0152] The transmitting and receiving unit 120 (transmitting processing unit 1211) can also perform channel coding (which may also include error correction coding), modulation, mapping, filter processing (filtering processing), discrete Fourier transform (DFT) processing (as needed), inverse fast Fourier transform (IFFT) processing), precoding, digital-to-analog conversion and other transmission processing on the bit string to be sent, and output a baseband signal.

[0153] The transmitting and receiving unit 120 (RF unit 122 ) may also perform modulation, filter processing, amplification, etc. on the baseband signal to a radio frequency band, and transmit the signal in the radio frequency band via the transmitting and receiving antenna 130 .

[0154] On the other hand, the transmitting and receiving unit 120 (RF unit 122 ) may also perform amplification, filter processing, and demodulation into a baseband signal on the radio frequency band signal received by the transmitting and receiving antenna 130 .

[0155] The transmitting and receiving unit 120 (receiving processing unit 1212) can also apply receiving processing such as analog-to-digital conversion, fast Fourier transform (FFT) processing, inverse discrete Fourier transform (IDFT) processing (as needed), filter processing, demapping, demodulation, decoding (which may also include error correction decoding), MAC layer processing, RLC layer processing, and PDCP layer processing to the obtained baseband signal to obtain user data, etc.

[0156] The transmitting and receiving unit 120 (measuring unit 123) may also perform measurements related to the received signal. For example, the measuring unit 123 may also perform radio resource management (RRM) measurements, channel state information (CSI) measurements, etc. based on the received signal. The measuring unit 123 may also measure received power (e.g., Reference Signal Received Power (RSRP)), received quality (e.g., Reference Signal Received Quality (RSRQ)), signal to interference plus noise ratio (SINR), signal to noise ratio (SNR)), signal strength (e.g., received signal strength indicator (RSSI)), propagation path information (e.g., CSI), etc. The measurement results may also be output to the control unit 110.

[0157] The transmission path interface 140 can also send and receive signals (return signaling) between the devices included in the core network 30, other base stations 10, etc., and can also obtain and transmit user data (user plane data) and control plane data for the user terminal 20.

[0158] In addition, the transmitting unit and the receiving unit of the base station 10 in the present disclosure may also be composed of at least one of the transmitting and receiving unit 120 , the transmitting and receiving antenna 130 , and the transmission path interface 140 .

[0159] Furthermore, the transmitting / receiving unit 120 may transmit a response to the report on the candidate beams to the user terminal 20 during the Beam Failure Recovery (BFR) procedure of the secondary cell.

[0160] The control unit 110 can also be assumed that after a certain period from the last codeword received in the response, the user terminal 20 uses the spatial domain filter associated with the reported candidate beam to send a measurement reference signal (Sounding Reference Signal (SRS)) resource in a specific cell.

[0161] (User Terminal)

[0162] Figure 6 This figure shows an example of the configuration of a user terminal according to one embodiment. The user terminal 20 includes a control unit 210, a transmitting / receiving unit 220, and a transmitting / receiving antenna 230. Furthermore, more than one of each of the control unit 210, the transmitting / receiving unit 220, and the transmitting / receiving antenna 230 may be provided.

[0163] In addition, in this example, the functional blocks of the characteristic parts of this embodiment are mainly shown, and it is also assumed that the user terminal 20 also has other functional blocks required for wireless communication. Part of the processing of each unit described below may also be omitted.

[0164] The control unit 210 controls the entire user terminal 20. The control unit 210 can be composed of a controller, a control circuit, and the like that are described based on common knowledge in the technical field to which this disclosure relates.

[0165] The control unit 210 may also control signal generation, mapping, etc. The control unit 210 may also control transmission, reception, measurement, etc. using the transmission and reception unit 220 and the transmission and reception antenna 230. The control unit 210 may also generate data, control information, sequences, etc. to be transmitted as signals and forward them to the transmission and reception unit 220.

[0166] The transceiver unit 220 may also include a baseband unit 221, an RF unit 222, and a measurement unit 223. The baseband unit 221 may also include a transmission processing unit 2211 and a reception processing unit 2212. The transceiver unit 220 may include a transmitter / receiver, an RF circuit, a baseband circuit, a filter, a phase shifter, a measurement circuit, a transceiver circuit, and the like, which are described based on common knowledge in the technical fields involved in this disclosure.

[0167] The transmitting and receiving unit 220 may be configured as an integrated transmitting and receiving unit or may be composed of a transmitting unit and a receiving unit. The transmitting unit may also be composed of a transmitting processing unit 2211 and an RF unit 222. The receiving unit may also be composed of a receiving processing unit 2212, an RF unit 222, and a measuring unit 223.

[0168] The transmitting and receiving antenna 230 can be formed of an antenna described based on common knowledge in the technical field involved in the present disclosure, such as an array antenna.

[0169] The transmitting and receiving unit 220 may also receive the aforementioned downlink channel, synchronization signal, downlink reference signal, etc. The transmitting and receiving unit 220 may also transmit the aforementioned uplink channel, uplink reference signal, etc.

[0170] The transmitting and receiving unit 220 may also use digital beamforming (eg, precoding), analog beamforming (eg, phase rotation), etc. to form at least one of a transmitting beam and a receiving beam.

[0171] The sending and receiving unit 220 (sending processing unit 2211) can also perform PDCP layer processing, RLC layer processing (for example, RLC retransmission control), MAC layer processing (for example, HARQ retransmission control), etc. on the data, control information, etc. obtained from the control unit 210 to generate a bit string to be sent.

[0172] The transmitting and receiving unit 220 (transmitting processing unit 2211) can also perform channel coding (which may also include error correction coding), modulation, mapping, filter processing, DFT processing (as needed), IFFT processing, precoding, digital-to-analog conversion and other transmission processing on the bit string to be sent, and output a baseband signal.

[0173] In addition, whether or not to apply DFT processing may also be based on the transform precoding setting. For a certain channel (e.g., PUSCH), if transform precoding is valid (enabled), the transmitting / receiving unit 220 (transmitting processing unit 2211) may perform DFT processing as the aforementioned transmission processing in order to transmit the channel using a DFT-s-OFDM waveform. Otherwise, the transmitting / receiving unit 220 (transmitting processing unit 2211) may perform DFT processing as the aforementioned transmission processing without performing DFT processing.

[0174] The transmitting and receiving unit 220 (RF unit 222 ) may also perform modulation, filter processing, amplification, etc. on the baseband signal to a radio frequency band, and transmit the signal in the radio frequency band via the transmitting and receiving antenna 230 .

[0175] On the other hand, the transmitting and receiving unit 220 (RF unit 222 ) may also perform amplification, filter processing, and demodulation into a baseband signal on the radio frequency band signal received by the transmitting and receiving antenna 230 .

[0176] The transmitting and receiving unit 220 (receiving processing unit 2212) can also apply receiving processing such as analog-to-digital conversion, FFT processing, IDFT processing (as needed), filter processing, demapping, demodulation, decoding (which may also include error correction decoding), MAC layer processing, RLC layer processing, and PDCP layer processing to the obtained baseband signal to obtain user data, etc.

[0177] The transmitting and receiving unit 220 (measuring unit 223) may also perform measurements related to received signals. For example, the measuring unit 223 may also perform RRM measurements, CSI measurements, etc. based on the received signals. The measuring unit 223 may also measure received power (e.g., RSRP), received quality (e.g., RSRQ, SINR, SNR), signal strength (e.g., RSSI), propagation path information (e.g., CSI), etc. The measurement results may also be output to the control unit 210.

[0178] In addition, the transmitting unit and the receiving unit of the user terminal 20 in the present disclosure may also be composed of at least one of the transmitting and receiving unit 220 , the transmitting and receiving antenna 230 , and the transmission path interface 240 .

[0179] In addition, the transmitting and receiving unit 220 may also receive a response (BFR response (related PDCCH)) to a report (eg, BFR MAC CE) on a candidate beam during a beam failure recovery (BFR) process of the secondary cell.

[0180] The control unit 210 may also be configured to transmit a sounding reference signal (SRS) resource in a specific cell using a spatial domain filter associated with the reported candidate beam after a certain period of time from the last symbol received in the response. This certain period of time may be, for example, 28 symbols or X symbols. The SRS resource may also be an A- / SP- / P-SRS resource.

[0181] The specific cell may also be a secondary cell to which the candidate beam is transmitted.

[0182] The specific cell may also be all secondary cells included in the cell group (PUCCH group) to which the secondary cell (PUCCH-SCell) to which the uplink control channel (PUCCH) is transmitted using a spatial domain filter associated with the reported candidate beam belongs after a certain period from the last codeword received in the response.

[0183] The SRS resource may also be an SRS resource included in an SRS resource set whose usage is set to codebook or non-codebook.

[0184] (Hardware Structure)

[0185] In addition, the block diagrams used in the description of the above embodiments show blocks of functional units. These functional blocks (structural units) are implemented by any combination of at least one of hardware and software. In addition, the implementation method of each functional block is not particularly limited. That is, each functional block can be implemented by a device that is physically or logically combined, or two or more physically or logically separated devices can be directly or indirectly (for example, by wired, wireless, etc.) connected and implemented by these multiple devices. The functional block can also be implemented by combining the above-mentioned one device or the above-mentioned multiple devices with software.

[0186] Here, the functions include judging, deciding, determining, calculating, calculating, processing, deriving, investigating, searching, confirming, receiving, sending, outputting, accessing, resolving, selecting, selecting, establishing, comparing, assuming, expecting, regarding, broadcasting, notifying, communicating, forwarding, configuring, reconfiguring, allocating, mapping, assigning, etc., but are not limited to these. For example, a functional block (structural unit) that implements a sending function may also be referred to as a transmitting unit, a transmitter, etc. Any of them are as described above, and the implementation method is not particularly limited.

[0187] For example, a base station, a user terminal, etc. in one embodiment of the present disclosure may also function as a computer that performs processing of the wireless communication method of the present disclosure. Figure 7This figure shows an example of the hardware configuration of a base station and a user terminal according to one embodiment. The base station 10 and user terminal 20 described above can also be physically configured as a computer device including a processor 1001, a memory 1002, a storage 1003, a communication device 1004, an input device 1005, an output device 1006, a bus 1007, and the like.

[0188] In addition, in this disclosure, the terms such as device, circuit, equipment, section, and unit are interchangeable. The hardware structure of the base station 10 and the user terminal 20 may include one or more of the devices shown in the figure, or may not include some of the devices.

[0189] For example, although only one processor 1001 is shown, multiple processors may be provided. Furthermore, processing may be performed by a single processor, or by two or more processors simultaneously, sequentially, or using other methods. Furthermore, processor 1001 may be implemented using more than one chip.

[0190] Regarding the various functions in the base station 10 and the user terminal 20, for example, they are achieved by reading specific software (program) into hardware such as the processor 1001 and the memory 1002, so that the processor 1001 performs calculations and controls communication via the communication device 1004, or controls at least one of the reading and writing of data in the memory 1002 and the storage 1003.

[0191] The processor 1001 controls the entire computer by, for example, operating an operating system. The processor 1001 may also be composed of a central processing unit (CPU) including an interface with peripheral devices, a control device, a computing device, registers, etc. For example, at least a portion of the control unit 110 (210) and the transmitting and receiving unit 120 (220) described above may also be implemented by the processor 1001.

[0192] In addition, the processor 1001 reads a program (program code), a software module, data, etc. from at least one of the storage 1003 and the communication device 1004 into the memory 1002 and performs various processes based on them. As a program, a program that causes a computer to perform at least a portion of the operations described in the above embodiments can be used. For example, the control unit 110 (210) can also be implemented by a control program stored in the memory 1002 and operated by the processor 1001, and the other functional blocks can also be implemented similarly.

[0193] The memory 1002 is a computer-readable recording medium and may be composed of, for example, at least one of a read-only memory (ROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), a random access memory (RAM), or other suitable storage medium. The memory 1002 may also be referred to as a register, a cache, a main memory (main storage device), etc. The memory 1002 can store executable programs (program code), software modules, etc. for implementing the wireless communication method according to an embodiment of the present disclosure.

[0194] The storage 1003 may also be a computer-readable recording medium, such as a flexible disk, a floppy disk, an optical disk (such as a compact disk (Compact Disc ROM (CD-ROM)), etc.), a digital versatile disk, a Blu-ray disk), a removable disk, a hard disk drive, a smart card, a flash memory device (such as a card, a stick, or a key drive), a magnetic stripe, a database, a server, or other suitable storage media. The storage 1003 may also be referred to as an auxiliary storage device.

[0195] The communication device 1004 is hardware (a transmitting and receiving device) for communicating between computers via at least one of a wired network and a wireless network, and is also referred to as a network device, a network controller, a network card, a communication module, or the like. To implement at least one of frequency division duplex (FDD) and time division duplex (TDD), the communication device 1004 may also include a high-frequency switch, a duplexer, a filter, a frequency synthesizer, and the like. For example, the aforementioned transmitting and receiving unit 120 (220), transmitting and receiving antenna 130 (230), and the like may also be implemented by the communication device 1004. The transmitting and receiving unit 120 (220) may also be implemented by physically or logically separating the transmitting unit 120a (220a) and the receiving unit 120b (220b).

[0196] The input device 1005 is an input device that receives input from the outside (e.g., a keyboard, mouse, microphone, switch, button, sensor, etc.). The output device 1006 is an output device that outputs to the outside (e.g., a display, speaker, light emitting diode (LED) lamp, etc.). Alternatively, the input device 1005 and the output device 1006 may be integrated (e.g., a touch panel).

[0197] Furthermore, the processor 1001, memory 1002, and other devices are connected via a bus 1007 for communicating information. The bus 1007 may be configured as a single bus or may be configured as different buses between the devices.

[0198] Furthermore, the base station 10 and the user terminal 20 may also be configured to include hardware such as a microprocessor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a programmable logic device (PLD), or a field programmable gate array (FPGA), and may use such hardware to implement part or all of each functional block. For example, the processor 1001 may also be implemented using at least one of these hardware components.

[0199] (Variation)

[0200] In addition, the terms described in this disclosure and the terms required for understanding this disclosure may also be replaced with terms having the same or similar meanings. For example, channel, symbol, and signal (signal or signaling) may be replaced with each other. In addition, a signal may also be a message. A reference signal may also be referred to as RS, or may be referred to as a pilot, pilot signal, etc. depending on the applied standard. In addition, a component carrier (CC) may also be referred to as a cell, frequency carrier, carrier frequency, etc.

[0201] A radio frame can also be composed of one or more periods (frames) in the time domain. Each period (frame) of the one or more periods (frames) that constitute a radio frame can also be called a subframe. Furthermore, a subframe can also be composed of one or more time slots in the time domain. A subframe can also be a fixed time length (e.g., 1 ms) that is independent of the parameter set (numerology).

[0202] Here, a parameter set may also refer to communication parameters applied to at least one of the transmission and reception of a signal or channel. For example, a parameter set may also represent at least one of subcarrier spacing (SCS), bandwidth, symbol length, cyclic prefix length, transmission time interval (TTI), the number of symbols per TTI, radio frame structure, specific filtering processing performed by the transmitter and receiver in the frequency domain, specific windowing processing performed by the transmitter and receiver in the time domain, and the like.

[0203] A time slot may also be composed of one or more symbols (Orthogonal Frequency Division Multiplexing (OFDM) symbols, Single Carrier Frequency Division Multiple Access (SC-FDMA) symbols, etc.) in the time domain. In addition, a time slot may also be a time unit based on a parameter set.

[0204] A time slot may also contain multiple mini-slots. Each mini-slot may also be composed of one or more symbols in the time domain. Furthermore, a mini-slot may also be referred to as a sub-slot. A mini-slot may also be composed of fewer symbols than a time slot. A PDSCH (or PUSCH) transmitted in a time unit larger than a mini-slot may also be referred to as PDSCH (PUSCH) mapping type A. A PDSCH (or PUSCH) transmitted using a mini-slot may also be referred to as PDSCH (PUSCH) mapping type B.

[0205] Radio frames, subframes, time slots, mini-time slots, and symbols all represent time units used for signal transmission. Radio frames, subframes, time slots, mini-time slots, and symbols may also be referred to by their respective equivalents. Furthermore, the terms frame, subframe, time slot, mini-time slot, and symbol may be used interchangeably in this disclosure.

[0206] For example, a subframe can be called a TTI, multiple consecutive subframes can be called a TTI, and a slot or a mini-slot can be called a TTI. That is, at least one of a subframe and a TTI can be a subframe (1ms) in existing LTE, a period shorter than 1ms (e.g., 1-13 symbols), or a period longer than 1ms. Furthermore, the unit representing a TTI can be called a slot, a mini-slot, or the like, rather than a subframe.

[0207] Here, TTI refers to, for example, the minimum time unit for scheduling in wireless communications. For example, in the LTE system, a base station schedules each user terminal by allocating radio resources (such as the frequency bandwidth and transmit power available to each user terminal) in TTI units. The definition of TTI is not limited to this.

[0208] The TTI may also be a unit of time for transmitting channel-coded data packets (transport blocks), code blocks, code words, etc., and may also be a unit of processing for scheduling, link adaptation, etc. Furthermore, when a TTI is given, the time interval (e.g., the number of symbols) to which the transport blocks, code blocks, code words, etc. are actually mapped may be shorter than the TTI.

[0209] In addition, when a time slot or a mini-time slot is called a TTI, one or more TTIs (i.e., one or more time slots or one or more mini-time slots) can also be the minimum time unit of scheduling. In addition, the number of time slots (mini-time slots) that constitute the minimum time unit of scheduling can also be controlled.

[0210] A TTI having a time length of 1 ms may also be referred to as a normal TTI (TTI in 3GPP Rel. 8-12), a standard TTI, a long TTI, a normal subframe, a standard subframe, a long subframe, a time slot, etc. A TTI shorter than a normal TTI may also be referred to as a shortened TTI, a short TTI, a partial TTI (partial or fractional TTI), a shortened subframe, a short subframe, a mini-slot, a subslot, a time slot, etc.

[0211] In addition, long TTI (for example, normal TTI, subframe, etc.) can also be replaced by TTI with a time length exceeding 1ms, and short TTI (for example, shortened TTI, etc.) can also be replaced by TTI with a TTI length smaller than long TTI and greater than 1ms.

[0212] A resource block (RB) is a unit of resource allocation in the time and frequency domains. In the frequency domain, it may also include one or more consecutive subcarriers (subcarriers). The number of subcarriers included in an RB may be the same regardless of the parameter set, for example, it may be 12. The number of subcarriers included in an RB may also be determined based on the parameter set.

[0213] In addition, an RB may also include one or more symbols in the time domain, and may also be the length of a slot, a mini-slot, a subframe, or a TTI. A TTI, a subframe, etc. may also be composed of one or more resource blocks.

[0214] In addition, one or more RBs may also be referred to as a physical resource block (Physical RB (PRB)), a sub-carrier group (Sub-Carrier Group (SCG)), a resource element group (Resource Element Group (REG)), a PRB pair, an RB pair, etc.

[0215] Furthermore, a resource block may be composed of one or more resource elements (REs). For example, one RE may be a radio resource region of one subcarrier and one symbol.

[0216] A Bandwidth Part (BWP) (also referred to as a fractional bandwidth) can also represent a subset of contiguous common resource blocks (RBs) used for a particular parameter set within a particular carrier. Common RBs can also be identified by their index relative to the common reference point of the carrier. PRBs can also be defined within a BWP and numbered within that BWP.

[0217] The BWP may include a UL BWP (BWP for UL) and a DL BWP (BWP for DL). For a UE, one or more BWPs may be configured within one carrier.

[0218] At least one of the configured BWPs may be activated, and the UE may not assume that it will transmit or receive specific signals / channels outside of the activated BWP. In addition, the terms "cell," "carrier," and the like in this disclosure may be replaced with "BWP."

[0219] The above-mentioned structures of radio frames, subframes, slots, mini-slots, and symbols are merely examples. For example, various modifications may be made to the number of subframes in a radio frame, the number of slots per subframe or radio frame, the number of mini-slots within a slot, the number of symbols and RBs within a slot or mini-slot, the number of subcarriers within an RB, the number of symbols within a TTI, the symbol length, and the cyclic prefix (CP) length.

[0220] Furthermore, the information and parameters described in this disclosure may be expressed as absolute values, relative values relative to a specific value, or other corresponding information. For example, wireless resources may be indicated by specific indexes.

[0221] The names used for parameters, etc. in this disclosure are not intended to be limiting in any respect. Furthermore, the mathematical formulas for these parameters may differ from those explicitly disclosed in this disclosure. Various channels (PUCCH, PDCCH, etc.) and information elements can be identified by any suitable names, and therefore, the various names assigned to these various channels and information elements are not intended to be limiting in any respect.

[0222] Information, signals, and the like described in this disclosure may also be represented using any of a variety of different technologies. For example, data, instructions, commands, information, signals, bits, symbols, chips, and the like that may be referred to throughout the foregoing description may also be represented by voltages, currents, electromagnetic waves, magnetic fields or magnetic particles, light fields or photons, or any combination thereof.

[0223] Furthermore, information, signals, etc. can be output in at least one of the following directions: from a higher layer (upper layer) to a lower layer (lower layer), and from a lower layer to a higher layer. Information, signals, etc. can also be input and output via multiple network nodes.

[0224] Input and output information, signals, etc. may be stored in a specific location (e.g., memory) or managed using a management table. Input and output information, signals, etc. may be overwritten, updated, or appended. Output information, signals, etc. may also be deleted. Input information, signals, etc. may also be sent to other devices.

[0225] The notification of information is not limited to the methods / implementations described in the present disclosure, and may also be performed by other methods. For example, the notification of information in the present disclosure may also be implemented through physical layer signaling (e.g., downlink control information (Downlink Control Information (DCI))), uplink control information (Uplink Control Information (UCI))), high-layer signaling (e.g., Radio Resource Control (RRC)) signaling, broadcast information (Master Information Block (MIB)), System Information Block (SIB), etc.), Medium Access Control (MAC) signaling), other signals, or a combination thereof.

[0226] In addition, physical layer signaling may also be referred to as Layer 1 / Layer 2 (L1 / L2) control information (L1 / L2 control signal), L1 control information (L1 control signal), etc. In addition, RRC signaling may also be referred to as RRC message, for example, RRC Connection Setup message, RRC Connection Reconfiguration message, etc. In addition, MAC signaling may also be notified using MAC Control Element (CE), for example.

[0227] Furthermore, notification of specific information (eg, notification of “it is X”) is not limited to explicit notification, but may be performed implicitly (eg, by not notifying the specific information or by notifying other information).

[0228] The determination can be made by a value represented by a bit (0 or 1), a true or false value (Boolean value) represented by true (true) or false (false), or by comparing numerical values (for example, comparing with a specific value).

[0229] The term “software” or “firmware” shall be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, sub-programs, software modules, applications, software applications, software packages, routines, sub-routines, objects, executable files, execution threads, procedures, functions, or the like.

[0230] Furthermore, software, instructions, information, and the like may also be transmitted and received via a transmission medium. For example, if the software is transmitted from a website, server, or other remote source using at least one of a wired technology (coaxial cable, fiber optic cable, twisted pair, Digital Subscriber Line (DSL), etc.) and a wireless technology (infrared, microwave, etc.), at least one of these wired and wireless technologies is included within the definition of a transmission medium.

[0231] The terms "system" and "network" used in this disclosure can be used interchangeably. "Network" may also refer to devices included in the network (eg, base stations).

[0232] In the present disclosure, terms such as "precoding", "precoder", "weight (precoding weight)", "Quasi-Co-Location (QCL)" "Transmission Configuration Indication state (TCI state)", "spatial relation", "spatial domain filter", "transmission power", "phase rotation", "antenna port", "antenna port group", "layer", "number of layers", "rank", "resource", "resource set", "resource group", "beam", "beam width", "beam angle", "antenna", "antenna element", and "panel" can be used interchangeably.

[0233] In this disclosure, terms such as "base station (BS)", "wireless base station", "fixed station", "NodeB", "eNB (eNodeB)", "gNB (gNodeB)", "access point", "transmission point (TP)", "reception point (RP)", "transmission / reception point (TRP))", "panel", "cell", "sector", "cell group", "carrier", and "component carrier" are used interchangeably. In some cases, a base station may be referred to as a macro cell, small cell, femto cell, or pico cell.

[0234] A base station can accommodate one or more (for example, three) cells. When a base station accommodates multiple cells, the overall coverage area of the base station can be divided into multiple smaller areas, each of which can also provide communication services through a base station subsystem (for example, a small base station for indoor use (Remote Radio Head (RRH))). Terms such as "cell" or "sector" refer to a part or the entire coverage area of at least one of a base station and a base station subsystem that provides communication services within that coverage area.

[0235] In the present disclosure, terms such as “mobile station (MS)”, “user terminal”, “user device (UE)”, and “terminal” can be used interchangeably.

[0236] The mobile station may also be referred to as a subscriber station, mobile unit, subscriber unit, wireless unit, remote unit, mobile device, wireless device, wireless communication device, remote device, mobile subscriber station, access terminal, mobile terminal, wireless terminal, remote terminal, hand set, user agent, mobile client, client, or several other appropriate terms.

[0237] At least one of the base station and the mobile station may also be referred to as a transmitting device, a receiving device, a wireless communication device, etc. Furthermore, at least one of the base station and the mobile station may also be a device mounted on a mobile object, a mobile object itself, etc. The mobile object may be a means of transportation (e.g., a vehicle, an airplane, etc.), a mobile object that moves unmanned (e.g., a drone, an autonomous vehicle, etc.), or a robot (manned or unmanned). Furthermore, at least one of the base station and the mobile station also includes a device that does not necessarily move when performing communication operations. For example, at least one of the base station and the mobile station may also be an Internet of Things (IoT) device such as a sensor.

[0238] In addition, the base station in the present disclosure may also be replaced by a user terminal. For example, the various methods / implementations of the present disclosure may also be applied to a structure in which the communication between a base station and a user terminal is replaced by communication between multiple user terminals (for example, which may also be referred to as device-to-device (D2D)), vehicle-to-everything (V2X), etc.). In this case, it may also be configured such that the user terminal 20 has the functions of the above-mentioned base station 10. In addition, terms such as "uplink" and "downlink" may also be replaced by terms corresponding to inter-terminal communication (for example, "side"). For example, uplink channels, downlink channels, etc. may also be replaced by side channels.

[0239] Likewise, the user terminal in the present disclosure may be replaced by a base station. In this case, the base station 10 may have the functions of the user terminal 20 described above.

[0240] In the present disclosure, actions are assumed to be performed by a base station, and sometimes, depending on the circumstances, by its upper node. Obviously, in a network including one or more network nodes including a base station, various operations performed for communication with a terminal may be performed by the base station, one or more network nodes other than the base station (for example, a Mobility Management Entity (MME)), a Serving-Gateway (S-GW), etc., but not limited to these), or a combination thereof.

[0241] The various methods / implementations described in this disclosure may be used individually or in combination, and may be switched between them during execution. Furthermore, the processing procedures, sequences, flow charts, and the like of the various methods / implementations described in this disclosure may be reversed as long as they do not conflict. For example, the elements of various steps described in this disclosure are presented in an illustrative order, but are not limited to the specific order presented.

[0242] The various modes and embodiments described in the present disclosure may also be applied to Long Term Evolution (LTE), LTE-Advanced (LTE-A), LTE-Beyond (LTE-B), SUPER 3G, IMT-Advanced, 4th generation mobile communication system (4G), 5th generation mobile communication system (5G), 6th generation mobile communication system (6G), xth generation mobile communication system (xG) (xG (x is, for example, an integer or a decimal)), Future Radio Access (FRA), New Radio Access Technology (RAT), New Radio (NR), New Radio Access (NX), Future Generation Radio Access (FX), Global System for Mobile Communications (GSM (registered trademark)), CDMA2000, Ultra Mobile Broadband (UMB), IEEE IEEE 802.11 (Wi-Fi (registered trademark)), IEEE 802.16 (WiMAX (registered trademark)), IEEE 802.20, Ultra-WideBand (UWB)), Bluetooth (registered trademark), systems using other appropriate wireless communication methods, and next-generation systems based on these. In addition, multiple systems can also be combined for application (for example, LTE or LTE-A, combined with 5G, etc.).

[0243] The phrase “based on” used in this disclosure does not mean “based only on” unless otherwise specified. In other words, the phrase “based on” means both “based only on” and “based at least on.”

[0244] Any reference to an element using the designations "first," "second," etc., as used in this disclosure, does not necessarily define the quantity or order of these elements. These designations may be used in this disclosure as a convenient means of distinguishing between two or more elements. Therefore, reference to a first and a second element does not necessarily mean that only two elements may be used or that the first element must in some way take precedence over the second element.

[0245] The term "determining" as used in this disclosure may encompass a variety of actions. For example, "determining" may also include judging, calculating, computing, processing, deriving, investigating, looking up (e.g., searching in a table, database, or other data structure), ascertaining, etc. as performing a "determination."

[0246] In addition, "judgment (decision)" can also be a situation where receiving (for example, receiving information), transmitting (for example, sending information), input (input), output (output), accessing (for example, accessing data in a memory), etc. are regarded as making a "judgment (decision)".

[0247] Furthermore, "judgment (decision)" can also refer to situations where resolving, selecting, choosing, establishing, comparing, etc. can be considered as "judgment (decision)". In other words, "judgment (decision)" can also refer to situations where certain actions can be considered as "judgment (decision)".

[0248] In addition, “judgment (decision)” can also be replaced by “assuming (assuming)”, “expecting (expecting)”, “considering (considering)” and so on.

[0249] The "maximum transmit power" recorded in this disclosure may mean the maximum value of the transmit power, the nominal maximum transmit power (the nominal UE maximum transmit power), or the rated maximum transmit power (the rated UE maximum transmit power).

[0250] As used in this disclosure, the terms "connected," "coupled," or any variation thereof, refer to any direct or indirect connection or coupling between two or more elements, and may include the presence of one or more intermediate elements between the two elements being "connected" or "coupled." The coupling or connection between elements may be physical, logical, or a combination thereof. For example, "connected" may be replaced by "access."

[0251] In the present disclosure, when two elements are connected, it is possible to consider using one or more wires, cables, printed electrical connections, etc., as well as using electromagnetic energy with wavelengths in the wireless frequency domain, microwave region, light (both visible and invisible) region, etc. as several non-limiting and non-inclusive examples to be "connected" or "combined" with each other.

[0252] In the present disclosure, the term "A is different from B" may also mean "A and B are different from each other." Alternatively, the term may also mean "A and B are each different from C." Terms such as "separate" and "bound" may also be interpreted in the same way as "different."

[0253] When used in this disclosure, "include," "including," and variations thereof have the same inclusive meaning as the term "comprising." Furthermore, the term "or" used in this disclosure does not mean an exclusive or.

[0254] In the present disclosure, when an article is added by translation, such as a, an, and the in English, the present disclosure may also include a case where the noun following the article is in a plural form.

[0255] While the inventions disclosed herein have been described in detail above, it will be apparent to those skilled in the art that the inventions disclosed herein are not limited to the embodiments described herein. The inventions disclosed herein can be implemented in modified and altered forms without departing from the spirit and scope of the invention as defined by the claims. Therefore, the descriptions in this disclosure are for illustrative purposes only and are not intended to limit the inventions disclosed herein in any way.

[0256] This application is based on Japanese Patent Application No. 2020-094109 filed on May 29, 2020, the contents of which are incorporated herein in their entirety.

Claims

1. A terminal comprising: a receiving unit that receives, during a beam failure recovery (BFR) process of a secondary cell, a downlink control information format (DCI format) as a response to a report of an index related to a channel state measurement reference signal (CSI-RS) or a synchronization signal block (SSB), wherein the report uses a medium access control control element (MAC CE); and A control unit that, after 28 symbols from the last codeword of the received physical downlink control channel, i.e., PDCCH, of the DCI format that schedules the transmission of a PUSCH having the same HARQ process number as that used in the transmission of the first physical uplink shared channel, i.e., PUSCH, for transmitting the MAC CE and having a switched new data indicator field value, i.e., NDI field value, controls the transmission of an SRS for an SRS resource set for beam management or antenna switching using the same spatial domain filter as the spatial domain filter corresponding to the index and using the transmission power of the SRS (Sounding Reference Signal) determined by a formula for determining the transmission power of the SRS based on the index.

2. The terminal according to claim 1, wherein: When the purpose is beam management, the SRS is an aperiodic SRS.

3. A wireless communication method, which is a wireless communication method of a terminal, comprising: In a beam failure recovery (BFR) process of a secondary cell, a step of receiving a downlink control information format (DCI) format as a response to a report of an index related to a channel state measurement reference signal (CSI-RS) or a synchronization signal block (SSB), wherein the report uses a medium access control control element (MAC CE); and After 28 symbols from the last symbol of the received physical downlink control channel, PDCCH, of the DCI format that schedules the transmission of the PUSCH having the same HARQ process number as that used in the transmission of the first physical uplink shared channel, PUSCH, for transmitting the MAC CE, and having the switched new data indicator field value, NDI field value, the transmission of the SRS for the SRS resource set used for beam management or antenna switching is controlled using the same spatial domain filter as that corresponding to the index and the transmission power of the SRS (Sounding Reference Signal) determined by the formula for determining the transmission power of the SRS based on the index.

4. A base station comprising: a transmitting unit, which transmits a downlink control information format (DCI format) as a response to a report of an index related to a channel state measurement reference signal (CSI-RS) or a synchronization signal block (SSB) to the terminal during a beam failure recovery (BFR) process of the secondary cell, wherein the report uses a medium access control control element (MAC CE); and A control unit controls, 28 symbols after the last symbol of the reception of the physical downlink control channel, i.e., PDCCH, of the DCI format in which the terminal schedules the transmission of a PUSCH having the same HARQ process number as that used in the transmission of the first physical uplink shared channel, i.e., PUSCH, for transmitting the MAC CE, and having a switched new data indicator field value, i.e., NDI field value, the reception of an SRS for an SRS resource set for beam management or antenna switching, which is transmitted using the same spatial domain filter as the spatial domain filter corresponding to the index and using the transmission power of the SRS determined by a formula for determining the transmission power of the SRS for measurement based on the index.

5. A system comprising a terminal and a base station, The terminal has: a receiving unit, receiving, during a beam failure recovery (BFR) process of a secondary cell, a downlink control information format (DCI format) as a response to a report of an index related to a channel state measurement reference signal (CSI-RS) or a synchronization signal block (SSB), wherein the report uses a medium access control control element (MAC CE); as well as a control unit that, 28 symbols after the last symbol of reception of a physical downlink control channel (PDCCH) of the DCI format that schedules transmission of a PUSCH having the same HARQ process number as that used in transmission of a first physical uplink shared channel (PUSCH) for transmitting the MAC CE and having a switched new data indicator field value (NDI field value), controls transmission of an SRS for an SRS resource set for beam management or antenna switching using the same spatial domain filter as the spatial domain filter corresponding to the index and using the transmission power of the sounding reference signal (SRS) determined by a formula for determining the transmission power of the SRS based on the index; The base station has: A sending unit, sending the response to the terminal; as well as A control unit controls the reception of the SRS.

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