Terminal, base station, system and wireless communication method

Abstract

A terminal involved in one embodiment of the present disclosure includes: a control unit that determines a BFR to be applied in a certain cell from a BFR based on a random access channel (physical random access channel (PRACH)) and a BFR based on a MAC CE, based on a radio resource control (Radio Resource Control (RRC)) parameter associated with a beam failure recovery (BFR) based on a medium access control control element (MAC CE); and a sending unit that sends the determined BFR when a BF is detected in the cell. According to one embodiment of the present disclosure, BFR operation can be properly performed when BFR based on MAC CE is introduced.

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) is standardized for the purpose of further high-speed data rates and low latency (Non-Patent Document 1). In addition, LTE-Advanced (3GPP Rel. 10-14) is standardized for the purpose of further increasing capacity and sophistication than LTE (Third Generation Partnership Project (3GPP) Release (Rel.) 8, 9).

[0003] Subsequent systems of LTE (for example, 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 discussed.

[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, a process for a user terminal (user terminal, User Equipment (UE)) to detect a beam failure (Beam Failure: BF) and switch to another beam (also referred to as a beam failure recovery (Beam Failure Recovery: BFR) process, BFR, etc.) is being studied.

[0009] In Rel.16NR, BFR based on Medium Access Control Control Element (MAC Control Element (MAC CE)) is studied.

[0010] In the discussion of Rel.16 so far, the above-mentioned MAC CE-based BFR is limited to the use of restoring the BF of the SCell. Therefore, it is studied to record in the specifications that the PCell or PSCell must comply with the PRACH-based BFR. On the other hand, if the MAC CE-based BFR can also be used for the PCell or PSCell, high-speed BFR can be achieved, which is more appropriate.

[0011] However, how to utilize MAC CE-based BFR for PCell or PSCell has not yet been studied. If such a structure is not clear, BFR cannot be properly utilized, and there is a risk of reduced throughput or deterioration in communication quality.

[0012] Therefore, one of the objectives of the present disclosure is to provide a terminal, a wireless communication method, and a base station that appropriately perform BFR operation when MAC CE-based BFR is introduced.

[0013] Means for solving problems

[0014] A terminal involved in one method of the present disclosure comprises: a control unit, which determines a BFR to be applied in a certain cell from a BFR based on a random access channel (physical random access channel (Physical Random Access Channel (PRACH))) and a BFR based on a MAC CE, based on a radio resource control (Radio Resource Control (RRC)) parameter associated with a beam failure recovery (BFR) based on a medium access control control element (Medium Access Control Control Element (MAC CE)); and a sending unit, which sends the BFR used for the decision when a BF is detected in the cell.

[0015] Effects of the Invention

[0016] According to one aspect of the present disclosure, when MAC CE-based BFR is introduced, BFR operation can be appropriately performed. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a diagram showing an example of the beam recovery process in Rel.15NR.

[0018] Figure 2 This is a diagram showing an example of the beam recovery process in Rel.16NR.

[0019] Figure 3 This is a diagram showing an example of the regulations for the operation of a UE for which RRC parameters associated with MAC CE-based BFR are not configured.

[0020] Figure 4 This is a diagram showing an example of the regulations for the operation of a UE in which RRC parameters associated with MAC CE-based BFR are set.

[0021] Figure 5 This is a diagram showing an example of a schematic configuration of a wireless communication system according to an embodiment.

[0022] Figure 6 This is a diagram showing an example of the configuration of a base station according to an embodiment.

[0023] Figure 7 This is a diagram showing an example of a configuration of a user terminal according to an embodiment.

[0024] Figure 8 This is a diagram showing an example of the hardware configuration of a base station and a user terminal involved in one embodiment. DETAILED DESCRIPTION

[0025] (Beam Failure Recovery)

[0026] In NR, research is being conducted on communication using beamforming. For example, a UE and a base station (e.g., a gNodeB (gNB)) may also use a beam used in signal transmission (also referred to as a transmit beam, Tx beam) and a beam used in signal reception (also referred to as a receive beam, Rx beam, etc.).

[0027] When beamforming is used, it is assumed that the radio link quality deteriorates because it is easily affected by obstacles. Due to the deterioration of radio link quality, there is a risk of frequent occurrence of radio link failure (RLF). If RLF occurs, the cell needs to be reconnected, so the frequent occurrence of RLF causes the deterioration of system throughput.

[0028] In NR, in order to suppress the occurrence of RLF, research is conducted on switching to other beams when the quality of a specific beam deteriorates (which may also be called beam recovery (BR), beam failure recovery (BFR), L1 / L2 (Layer 1 / Layer 2) beam recovery, etc.). In addition, the BFR procedure may also be referred to as BFR.

[0029] In addition, beam failure (Beam Failure: BF) in the present disclosure may also be referred to as link failure (link failure) or radio link failure (RLF).

[0030] 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 implements measurement based on the reference signal (RS) resources sent using two beams.

[0031] The RS may be at least one of a synchronization signal block (SSB) and a channel state information RS (CSI-RS). In addition, SSB may also be referred to as a SS / PBCH (Physical Broadcast Channel) block or the like.

[0032] RS may also 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, etc., or a signal formed by extending or changing them. The RS measured in step S101 may also be referred to as an RS for beam failure detection (BFD-RS), etc.

[0033] In step S102, the UE cannot detect the BFD-RS (or the reception quality of the RS deteriorates) because the beam from the base station is obstructed. Such obstruction may occur due to, for example, obstacles, attenuation, interference, etc. between the UE and the base station.

[0034] If certain conditions are met, the UE detects a beam failure. The UE can also detect the occurrence of a beam failure when the block error rate (BLER) for all configured BFD-RS (BFD-RS resource settings) is less than a threshold. If the occurrence of a beam failure is detected, the lower layer (physical (PHY) layer) of the UE can also notify (indicate) the upper layer (MAC layer) of the beam failure instance.

[0035] In addition, the criterion (standard) for judgment is not limited to BLER, but can also be the reference signal received power (Layer 1 Reference Signal Received Power: L1-RSRP) of the physical layer. In addition, beam failure detection is implemented based on downlink control channels (Physical Downlink Control Channel (PDCCH)) instead of RS measurement or in addition to RS measurement. It can also be expected that BFD-RS and the DMRS of the PDCCH monitored by the UE will be quasi-co-located (Quasi-C-Location: QCL).

[0036] Here, QCL is an indicator indicating the statistical properties of a channel. For example, when a certain signal / channel is in a QCL relationship with other signals / channels, it can also mean that it can be assumed that at least one of Doppler shift, Doppler spread, average delay, delay spread, and spatial parameter (e.g., spatial receive filter / parameter, spatial transmit filter parameter) is the same between these different multiple signals / channels (at least one of these is in QCL).

[0037] In addition, the spatial reception parameter may also correspond to a reception beam of the UE (eg, a reception analog beam), or the beam may be determined based on a spatial QCL. The QCL (or at least one element of the QCL) in the present disclosure may also be renamed as spatial QCL (sQCL).

[0038] Information related to BFD-RS (e.g., RS index, resources, number, number of ports, precoding, etc.), information related to beam failure detection (BFD) (e.g., the above-mentioned threshold), etc. can also be set (notified) to the UE through high-layer signaling, etc. The information related to BFD-RS can also be referred to as information related to BFR resources, etc.

[0039] In the present disclosure, the high-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.

[0040] MAC signaling may also utilize, for example, MAC Control Element (CE), MAC Protocol Data Unit (PDU), etc. Broadcast information may also include, for example, Master Information Block (MIB), System Information Block (SIB), minimum system information (Remaining Minimum System Information: RMSI), Other System Information (OSI), etc.

[0041] 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 later) if it receives a beam failure instance notification more than a certain number of times (e.g., beamFailureInstanceMaxCount set by RRC) before the timer expires.

[0042] The base station may also determine that the UE has detected a beam failure when there is no 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.

[0043] In step S103, the UE starts searching for a new candidate beam (new candidate beam) to be used for communication again for beam recovery. 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 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 (new candidate beam), a candidate beam or a new beam (new beam).

[0044] The UE may also determine the beam corresponding to the RS that satisfies specific conditions as a new candidate beam. For example, the UE may also determine a new candidate beam based on the RS in the set NCBI-RS whose L1-RSRP exceeds the threshold. In addition, the criterion (standard) for judgment is not limited to L1-RSRP. It may also be determined by using at least one of L1-RSRP, L1-RSRQ, and L1-SINR (signal to noise plus interference power ratio). The L1-RSRP related to SSB may also be referred to as SS-RSRP. The L1-RSRP related to CSI-RS may also be referred to as CSI-RSRP. Similarly, the L1-RSRQ related to SSB may also be referred to as SS-RSRQ. The L1-RSRQ related to CSI-RS may also be referred to as CSI-RSRQ. In addition, similarly, the L1-SINR related to SSB may also be referred to as SS-SINR. The L1-SINR related to CSI-RS may also be referred to as CSI-SINR.

[0045] Information related to NCBI-RS (e.g., RS resources, number, number of ports, precoding, etc.), information related to new candidate beam identification (NCBI) (e.g., the above-mentioned threshold), etc. can also be set (notified) to the UE using high-layer signaling, etc. 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, etc.

[0046] In addition, BFD-RS, NCBI-RS, etc. may also be renamed as Radio Link Monitoring Reference Signal (RLM-RS: Radio Link Monitoring RS).

[0047] In step S104, the UE that has determined the new candidate beam sends a beam recovery request (Beam Failure Recovery request: BFRQ). The beam recovery request may also be called a beam recovery request signal, a beam failure recovery request signal, or the like.

[0048] 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. Resources used for BFRQ can also be associated with the new candidate beam. The beam information can also be notified using a beam index (BeamIndex: BI), a port index of a specific reference signal, a resource index (for example, a CSI-RS resource indicator (CSI-RSResource Indicator: CRI), an SSB resource indicator (SSBRI)), etc.

[0049] In Rel.15NR, BFR based on contention-based random access (Random Access: RA) process, namely CB-BFR (Contention-Based BFR), and BFR based on non-contention-based random access process, namely CF-BFR (Contention-Free BFR). In CB-BFR and CF-BFR, UE can also use PRACH resources to send preamble (also called RA preamble, random access channel (Physical Random Access Channel: PRACH), RACH preamble, etc.) as BFRQ.

[0050] In step S105, the base station that detects the BFRQ sends a response signal (also referred to as a BFR response, a gNB response, etc.) to the BFRQ from the UE. The response signal may also include reconstruction information about one or more beams (e.g., composition information of DL-RS resources).

[0051] The response signal may also be sent in a UE common search space such as a PDCCH. The response signal may also be notified using a PDCCH (DCI) having a cyclic redundancy check (CRC) scrambled by an identifier of the UE (e.g., a cell-radio RNTI (C-RNTI)). The UE may also determine at least one of the transmit beam and receive beam to be used based on the beam reconstruction information.

[0052] The UE may monitor the response signal based on at least one of a control resource set (CORESET) for BFR and a search space set for BFR. For example, the UE may detect a DCI having a CRC scrambled by a C-RNTI in a BFR search space in a dedicated CORESET.

[0053] Regarding CB-BFR, when the UE receives the PDCCH corresponding to the C-RNTI related to itself, it is determined that contention resolution has succeeded.

[0054] Regarding the processing of step S105, a period for the UE to monitor a response to the BFRQ from a base station (e.g., gNB) may also be set. This period may also be referred to as, for example, a gNB response window, a gNB window, a beam recovery request response window, a BFRQ response window, etc. The UE may also retransmit the BFRQ if no gNB response is detected during the window.

[0055] In step S106, the UE may also send a message to the base station indicating that the beam reconfiguration has been completed. The message may be sent, for example, via the PUCCH or the PUSCH.

[0056] In step S106, the UE may receive RRC signaling indicating the setting of the transmission configuration indication state (TCI state) used in the PDCCH, and may receive a MAC CE indicating activation of the setting.

[0057] 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).

[0058] In addition, the numbers of these steps are only for explanation, and multiple steps may be combined or the order may be changed. In addition, whether to implement BFR may be set to the UE using higher layer signaling.

[0059] (BFR based on MAC CE)

[0060] However, in future wireless communication systems (for example, after Rel.16), research is being conducted on using the uplink control channel (PUCCH) and MAC control information (MAC CE) to notify the occurrence of a beam failure, report information about the cell (or CC) where the beam failure was detected, and report information about new candidate beams.

[0061] For example, consider that after the UE detects a beam failure, it 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 2 steps.

[0062] Compared with PRACH, the uplink control channel can set resources more flexibly in the time domain. Therefore, it is effective to use the uplink control channel (PUCCH) as a channel used in the occurrence of BFRQ. In addition, compared with PRACH, the MAC CE (PUSCH) can set resources more flexibly in the time domain. Therefore, it is effective to use the MAC CE (PUSCH) as a channel used in the transmission of BFRQ.

[0063] Using the Figure 2 The BFR reported by the MAC CE shown may also be called MAC CE based BFR, 2-step BFR, Rel.16BFR, etc., and is called SCell BFR because it can be used to recover beam failure of the secondary cell (SCell).

[0064] In addition, the above Figure 1 The BFR can also be called PRACH-based BFR, PRACH-based Primary Cell (PCell) BFR, Rel.15 BFR, etc.

[0065] exist Figure 2 In the first step (or, step 1), the UE first detects the occurrence of a beam failure in a certain cell (e.g., SCell). This detection can also be performed by the same method as Rel.15BFR. In the first step (or, step 1), the UE uses the uplink control channel (PUCCH) to notify the occurrence of the beam failure.

[0066] The UE that has detected the occurrence of a beam failure searches for a new candidate beam in the above-mentioned cell. It is assumed that the UE reports at least one of information related to the cell in which the beam failure was detected and information related to the new candidate beam using MAC control information (e.g., MAC CE, or MAC PDU including MAC CE) in step 2 (or, step 2).

[0067] In the following description, the information transmitted in the first step is also referred to as the first information, and the information transmitted in the second step is also referred to as the second information.

[0068] The PUCCH in step 1 may also use the same method as the sending of the scheduling request (SR). For example, the UE may also use the SR to send the first information for notifying the occurrence of a beam failure during the BFR process. The SR used in the notification of the occurrence of a beam failure may also be referred to as a BFR SR, a BFR SR for SCell, a dedicated SR for SCell, a dedicated SR, a Link Recovery Request (LRR), etc.

[0069] The MAC CE (or MAC PDU) in step 2 may also be sent using uplink resources. For example, the UE may also send the MAC CE using uplink resources allocated from the base station through the PUCCH (e.g., dedicated SR-like PUCCH) in step 1. The MAC CE may also be referred to as a MAC CE for BFR.

[0070] The uplink resources may also be renamed as resources (UL-SCH resources) used for logical uplink channels (eg, uplink shared channels (UL-SCH))), or resources used for physical uplink channels (eg, physical uplink shared channels (Physical Uplink Shared Channel)).

[0071] The format of the PUCCH used in step 1 may be, for example, PUCCH format (PF) 0 or 1. In addition, the PUCCH transmission in step 1 may also be performed in a specific cell (e.g., a primary cell (PCell) or a primary secondary cell (PSCell)). PF0 may also be composed of 1 or 2 symbols. On the other hand, PF1 may also be composed of 4 or more symbols.

[0072] The PUCCH resources for BFR of the SCell in step 1 may also be set in common for all SCells included in a specific group (e.g., the same cell group). In addition, the UE may not send the PUCCH in step 1 if it detects a beam failure and receives UL permission in a cell that can send a MAC CE for BFR before sending the PUCCH (or SR) in step 1.

[0073] The transmission of MAC CE (PUSCH transmission) in the second step may be performed in the above-mentioned specific cell (eg, PCell or PSCell).

[0074] Even if the UE detects a beam failure, when a new candidate beam cannot be determined, the MAC CE in step 2 includes information about the cell where the beam failure was detected, and does not include the index of the new candidate beam. The situation where a new candidate beam cannot be determined may also be, for example, the situation where there is no reference signal whose received power (RSRP) is greater than a specific value.

[0075] In the discussion of Rel.16 so far, the above-mentioned MAC CE-based BFR is limited to the use of restoring the BF of the SCell. Therefore, it is studied to record in the specifications that the PCell or PSCell must comply with the PRACH-based BFR. On the other hand, if the MAC CE-based BFR can also be used for the PCell or PSCell, high-speed BFR can be achieved, which is more appropriate.

[0076] However, how to utilize MAC CE-based BFR for PCell or PSCell has not yet been studied. If such a structure is not clear, BFR cannot be properly utilized, and there is a risk of reduced throughput or deterioration in communication quality.

[0077] Therefore, the inventors of the present invention have conceived a method for properly performing BFR operation when MAC CE-based BFR is introduced.

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

[0079] In the present disclosure, "A / B" and "at least one of A and B" may also be used interchangeably.

[0080] In the present disclosure, index, ID, and indicator resource ID may also be interchangeable.

[0081] In addition, the special cell (Special Cell (SpCell)) in the following description may be renamed as PCell / PSCell. SpCell may also mean a cell other than PCell / PSCell.

[0082] (Wireless Communication Method)

[0083] In one embodiment of the present disclosure, the UE determines whether to use PRACH-based BFR or MAC CE-based BFR in the SpCell according to RRC parameters associated with MAC CE-based BFR.

[0084] For example, when RRC parameters associated with MAC CE-based BFR are not configured for the SpCell, the UE may apply PRACH-based BFR for the SpCell.

[0085] When RRC parameters associated with MAC CE-based BFR are configured for any cell (which can be a SpCell or a SCell), the UE may apply MAC CE-based BFR for the cell.

[0086] Here, the RRC parameter associated with the MAC CE-based BFR may also be a parameter related to at least one of the following:

[0087] A threshold for new candidate beam identification (e.g., an RRC parameter “rsrp-ThresholdSSBBFR” indicating a range of values ​​for RSRP);

[0088] A list of beam failure detection resources (e.g., an RRC parameter “beamFailureDetectionResourceList” indicating a list of one or more CSI-RS resource IDs);

[0089] A dedicated SR for MAC CE-based BFR (e.g., an RRC parameter “schedulingRequestIDForBFR” indicating the ID of the SR);

[0090] The cell identified as a new candidate beam for MAC CE-based BFR (e.g., the RRC parameter “cell” representing the serving cell index (ServCellIndex));

[0091] Resources for identifying new candidate beams for MAC CE-based BFR (e.g., RRC parameters indicating at least one of the SSB index, CSI-RS resource ID, the above-mentioned “cell”, etc.)

[0092] “candidateBeamResource”);

[0093] · A resource list for new candidate beam identification for MAC CE-based BFR (e.g., an RRC parameter representing a list of the above-mentioned “candidateBeamResource”

[0094] “candidateBeamResourceList”);

[0095] · The maximum count number of beam failure instances for beam failure detection of MAC CE-based BFR (e.g., the RRC parameter “beamFailureInstanceMaxCount”);

[0096] · Enable of MAC CE-based BFR (e.g., the RRC parameter

[0097] “MACCEbasedBFR”).

[0098] In addition, “MAC CE-based BFR” in the description of the above parameters can also be simply renamed “Rel.16 NR” (not necessarily parameters for MAC CE-based BFR, for example, they can also be parameters commonly used with PRACH-based BFR). In addition, each RRC parameter can also be given a suffix such as “-r16” indicating for Rel. 16 and later.

[0099] The UE can also report capability information indicating support for MAC CE-based BFR for the SpCell to the network. When the UE that has reported this capability information is set with RRC parameters associated with MAC CE-based BFR for the SpCell, it can also apply MAC CE-based BFR for the SpCell. The UE that does not report this capability information can also apply PRACH-based BFR for the SpCell regardless of whether RRC parameters associated with MAC CE-based BFR are set for the SpCell.

[0100] <Transmission of SR for BFR / MAC CE for BFR>

[0101] In MAC CE-based BFR, the SR for BFR / MAC CE for BFR is preferably transmitted in a cell different from the cell in which BF is detected.

[0102] Therefore, in MAC CE-based BFR, the UE can also assume at least one of the following:

[0103] (1) Regarding the BFR of the first cell (the BFR for the BF detected in the first cell), in a second cell (e.g., SCell) different from the first cell, a BFR SR / BFR MAC CE is sent (not sent in the SpCell of the BF);

[0104] (2) Regarding the BFR of the first cell, when the SR for BFR is transmitted in the first cell, resources for a plurality of SRs for BFR are set (for example, each resource is time-division multiplexed (TDM)) assuming a plurality of beams, and a resource corresponding to the detected new candidate beam is selected from these resources to transmit the SR for BFR. In addition, a spatial domain filter corresponding to the detected new candidate beam may be applied to transmit the PUCCH corresponding to the SR for BFR;

[0105] (3) When a MAC CE for BFR is transmitted in the first cell regarding the BFR of the first cell, a spatial domain filter corresponding to the detected new candidate beam is applied, and a PUSCH corresponding to the MAC CE for BFR is transmitted.

[0106] According to (1), when the beams used in the first cell and the second cell are different, BFR in the first cell can be appropriately implemented. According to (2) and (3), BFR based on MAC CE can be appropriately implemented only in the first cell.

[0107] The PUSCH / PUCCH transmission in the above (2) and (3) that applies the spatial domain filter corresponding to the new candidate beam may also mean the transmission using the same spatial domain reception filter as the spatial domain reception filter used for receiving the reference signal (e.g., SSB, CSI-RS) used in the detection of the new candidate beam.

[0108] In addition, in accordance with the above (2), the UE detects new candidate beams in the above first cell after detecting the above first BF and before sending the SR for BFR.

[0109] In addition, for example, when the first cell is a SpCell, the second cell may also be equivalent to an SCell or another SpCell. When the first cell is a SCell, the second cell may also be equivalent to another SCell or SpCell.

[0110] In addition, the first cell and the second cell may belong to different frequency ranges (for example, FR1~FR2 carrier aggregation and FR2~FR1 carrier aggregation may also be applied to these cells), or may belong to different frequency bands (for example, inter-band carrier aggregation (inter-band CA) may also be applied to these cells).

[0111] <An example of a standard article>

[0112] When the operation of the above-described embodiment of the present disclosure is specified as a standard article, for example, considering Figure 3 as well as Figure 4 The content shown. Figure 3 This is a diagram showing an example of the regulations for the operation of a UE for which RRC parameters associated with MAC CE-based BFR are not configured. Figure 4 This is a diagram showing an example of regulations for the operation of a UE in which RRC parameters associated with BFR based on a MAC CE are also configured.

[0113] "[Rel.16RRC parameter]" in these examples may also mean the RRC parameters associated with the above-mentioned MAC CE-based BFR. In addition, not all of these provisions may be adopted.

[0114] about Figure 3 For example, since the recovery search space is used for BFR based on PRACH, it is shown that it is used when [Rel.16RRC parameter] is not set for UE. In addition, it is shown that the QCL assumption based on the recovery search space is also used when [Rel.16RRC parameter] is not set for UE.

[0115] about Figure 4 , for example, when [Rel.16RRC parameter] is set for the UE, a MAC CE for BFR is sent to a serving cell (not limited to SCell) whose radio quality is worse than the threshold. Figure 4 For example, when BF occurs in SpCell, it is possible to implement UE operation of BFR only through the processing of SpCell. For example, the beams of PDCCH and PUCCH of the SpCell can be updated to new beams.

[0116] according to Figure 4, for the SCell(s) in which beam failure is detected, the UE may also perform the following operations after 28 symbols from the last symbol received from the PDCCH of the DCI format that schedules a PUSCH transmission with the same HARQ process number as that utilized in the first PUSCH transmission for transmitting the MAC CE for BFR and the DCI format with a switched New Data Indicator (NDI) field value:

[0117] ·Use and index q new Monitor the PDCCH in all CORESETs of the SCell(s) indicated by the MAC CE with the same QCL parameters for the relevant antenna ports;

[0118] ·Use and index q new The same spatial domain filter is used to receive the relevant CSI-RS / SSB, and the PUCCH of the PUCCH-SCell is sent (only when the PUCCH-SCell is included in the above SCell(s) indicated by the above MAC CE, and LRR is not sent in the PUCCH-SCell, etc. Figure 4 conditions described in the ).

[0119] In addition, q new It may also be an index related to a new candidate beam (e.g., SSB / CSI-RS) reported by the UE during the BFR process. In addition, the SCS setting for the above 28 codewords may also be equivalent to the minimum SCS setting among the SCS setting of the activated DLBWP for the above PDCCH reception and the SCS setting of the activated DL BWP for the SCell(s) in which the above beam failure is detected.

[0120] In addition, according to Figure 4 , for the PCell or PSCell in which beam failure is detected, the UE may also perform the following operations after 28 symbols have passed from the last symbol received from the PDCCH of the DCI format, wherein the DCI format schedules a PUSCH transmission with a HARQ process number that is the same as the HARQ process number utilized in the first PUSCH transmission for transmitting the MAC CE for BFR and the DCI format has a switched New Data Indicator (NDI) field value:

[0121] ·Use and index q new The same QCL parameters of the antenna ports concerned monitor the PDCCH in all CORESETs of the PCell or PSCell indicated by the MAC CE;

[0122] ·Use and index q new The same spatial domain filter is used to receive the relevant CSI-RS / SSB, and the PUCCH of the PCell or PSCell is sent (only when the above-mentioned PCell or PSCell is included in the serving cell indicated by the above-mentioned MAC CE, and LRR is not sent in the above-mentioned PCell or PSCell, etc. Figure 4 conditions described in the ).

[0123] In addition, the SCS setting for the above-mentioned 28 codewords can also be equivalent to the minimum SCS setting among the SCS setting for activating the DLBWP for the above-mentioned PDCCH reception and the SCS setting for activating the DL BWP for the service cell in which the above-mentioned beam failure is detected.

[0124] According to one embodiment of the present disclosure described above, it is possible to appropriately determine whether to apply MAC CE-based BFR to any cell.

[0125] (Wireless Communication System)

[0126] Hereinafter, a configuration of a wireless communication system according to an embodiment of the present disclosure will be described. In the wireless communication system, communication is performed using any one of the wireless communication methods according to the above-mentioned embodiments of the present disclosure or a combination thereof.

[0127] Figure 5 1 is a diagram showing an example of a schematic structure of a wireless communication system involved in 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), and the like.

[0128] 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-UTRAN-NR Dual Connectivity (EN-DC)), dual connectivity between NR and LTE (NR-E-UTRA Dual Connectivity (NR-E-UTRA Dual Connectivity (NE-DC)), etc.

[0129] In EN-DC, the base station (eNB) of LTE (E-UTRA) is the master node (Master Node (MN)), and the base station (gNB) of NR is the secondary node (Secondary Node (SN)). In NE-DC, the base station (gNB) of NR is the MN, and the base station (eNB) of LTE (E-UTRA) is the SN.

[0130] 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 (NR-NR Dual Connectivity) (NN-DC)) where both MN and SN are NR base stations (gNB)).

[0131] The wireless communication system 1 may also include a base station 11 that forms a macro cell C1 with a wide coverage, and a base station 12 (12a-12c) that is arranged in the macro cell C1 and forms a small cell C2 that is narrower than the macro cell C1. The user terminal 20 may also be located in at least one cell. The arrangement and number of each cell and the user terminal 20 are not limited to the illustrated method. Hereinafter, when the base stations 11 and 12 are not distinguished, they are collectively referred to as the base station 10.

[0132] The user terminal 20 may be connected to at least one of the plurality of base stations 10. The user terminal 20 may use at least one of carrier aggregation (CA) using a plurality of component carriers (CC) and dual connectivity (DC).

[0133] 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 be included in FR1, and the small cell C2 may be included in FR2. For example, FR1 may be a frequency band 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 thereto. For example, FR1 may correspond to a frequency band higher than FR2.

[0134] Furthermore, the user terminal 20 may communicate in each CC using at least one of time division duplex (TDD) and frequency division duplex (FDD).

[0135] Multiple base stations 10 can be connected by wired (e.g., optical fiber, X2 interface, etc. in accordance with Common Public Radio Interface (CPRI)) or wireless (e.g., NR communication). For example, when NR communication is used as a backhaul between base stations 11 and 12, the base station 11 equivalent to a high-level station can be called an Integrated Access Backhaul (IAB) host, and the base station 12 equivalent to a relay station (relay) can also be called an IAB node.

[0136] The base station 10 may also be connected to the core network 30 via other base stations 10, or directly connected to the core network 30. The core network 30 may also include, for example, at least one of an evolved packet core (EPC), a 5G core network (5G Core Network (5GCN)), a next generation core (NGC), and the like.

[0137] The user terminal 20 may also be a terminal that supports at least one of communication modes such as LTE, LTE-A, and 5G.

[0138] In the wireless communication system 1, a wireless access method based on orthogonal frequency division multiplexing (OFDM) may be used. For example, in at least one of the downlink (DL) and the uplink (UP), cyclic prefix OFDM (CP-OFDM), discrete Fourier transform spread OFDM (DFT-s-OFDM), orthogonal frequency division multiple access (OFDMA), single carrier frequency division multiple access (SC-FDMA), etc. may be used.

[0139] The radio access scheme may also be referred to as a waveform. In the wireless communication system 1, other radio access schemes (for example, other single-carrier transmission schemes, other multi-carrier transmission schemes) may be used as the radio access schemes for UL and DL.

[0140] In the wireless communication system 1, as a downlink channel, a downlink shared channel (Physical Downlink Shared Channel (PDSCH)), a broadcast channel (Physical Broadcast Channel (PBCH)), a downlink control channel (Physical Downlink Control Channel (PDCCH)), etc. shared by each user terminal 20 can also be used.

[0141] In addition, in the wireless communication system 1, as uplink channels, 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)) and the like may be used.

[0142] The PDSCH transmits user data, high-layer control information, system information block (SIB), etc. The PUSCH transmits user data, high-layer control information, etc. In addition, the PBCH transmits the master information block (MIB).

[0143] The PDCCH may also transmit lower layer control information. The lower layer control information may include, for example, downlink control information (DCI: Downlink Control Information) including scheduling information of at least one of the PDSCH and the PUSCH.

[0144] In addition, the DCI for scheduling the PDSCH may also be referred to as DL allocation, DL DCI, etc., and the DCI for scheduling 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.

[0145] In the detection of PDCCH, the control resource set (CORESET) and the search space can also be used. CORESET corresponds to the resources for searching DCI. The search space corresponds to the search area and search method of 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 setting.

[0146] A search space may also correspond to a PDCCH candidate 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 "search space", "search space set", "search space setting", "search space set setting", "CORESET", "CORESET setting" and the like in the present disclosure may also be interchangeable.

[0147] Through PUCCH, uplink control information (uplink control information (UCI)) including at least one of channel state information (CSI), delivery confirmation information (e.g., also called hybrid automatic repeat request confirmation (HARQ-ACK), ACK / NACK, etc.), and scheduling request (Scheduling Request (SR)) can also be transmitted. Through PRACH, random access preamble codes used to establish a connection with a cell can also be transmitted.

[0148] In the present disclosure, downlink, uplink, etc. may be expressed without adding "link". In addition, various channels may be expressed without adding "Physical" to the beginning.

[0149] In the wireless communication system 1, a synchronization signal (Synchronization Signal (SS)), a downlink reference signal (Downlink Reference Signal (DL-RS)), etc. may also be transmitted. In the wireless communication system 1, as DL-RS, 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. may also be transmitted.

[0150] The synchronization signal may also be, for example, at least one of a primary synchronization signal (PSS) and a secondary synchronization signal (SSS). A signal block including SS (PSS, SSS) and PBCH (and DMRS for PBCH) may also be referred to as SS / PBCH block, SS block (SS Block (SSB)), etc. In addition, SS, SSB, etc. may also be referred to as reference signals.

[0151] 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 (UE-specific Reference Signal)).

[0152] (Base Station)

[0153] Figure 6 1 is a diagram showing an example of a structure of a base station according to an embodiment. The base station 10 includes a control unit 110, a transmitting and receiving unit 120, a transmitting and receiving antenna 130, and a transmission line interface 140. In addition, the control unit 110, the transmitting and receiving unit 120, the transmitting and receiving antenna 130, and the transmission line interface 140 may each include more than one.

[0154] In addition, in this example, the functional blocks of the characteristic parts of this embodiment are mainly shown, and it is also conceivable that the base station 10 also has other functional blocks necessary for wireless communication. Part of the processing of each unit described below may also be omitted.

[0155] The control unit 110 controls the entire base station 10. The control unit 110 can be configured by a controller, a control circuit, and the like that are described based on common knowledge in the technical field to which the present disclosure relates.

[0156] The control unit 110 may also control signal generation, scheduling (e.g., resource allocation, mapping), etc. The control unit 110 may also control transmission, reception, measurement, etc. using the transmission and reception unit 120, the transmission and reception antenna 130, and the transmission path interface 140. The control unit 110 may also generate data, control information, sequences, etc. to be sent as signals, and forward them to the transmission and reception unit 120. The control unit 110 may also perform call processing (setting, release, etc.) of communication channels, state management of the base station 10, management of wireless resources, etc.

[0157] The transmitting and receiving unit 120 may also include a baseband unit 121, a radio frequency (RF) unit 122, and a measuring unit 123. The baseband unit 121 may also include a transmitting processing unit 1211 and a receiving processing unit 1212. The transmitting and receiving unit 120 may be composed of a transmitter / receiver, an RF circuit, a baseband circuit, a filter, a phase shifter, a measuring circuit, a transmitting and receiving circuit, etc., which are explained based on the common knowledge in the technical field involved in the present disclosure.

[0158] The transmitting and receiving unit 120 may be configured as an integrated transmitting and receiving unit, or may be configured by a transmitting unit and a receiving unit. The transmitting unit may also be configured by a transmitting processing unit 1211 and an RF unit 122. The receiving unit may also be configured by a receiving processing unit 1212, an RF unit 122, and a measuring unit 123.

[0159] The transmitting / receiving antenna 130 can be constituted by an antenna such as an array antenna, which is described based on the common knowledge in the technical field to which the present disclosure relates.

[0160] The transmitting and receiving unit 120 may also transmit the above-mentioned downlink channel, synchronization signal, downlink reference signal, etc. The transmitting and receiving unit 120 may also receive the above-mentioned uplink channel, uplink reference signal, etc.

[0161] The transmitting and receiving unit 120 may also form at least one of a transmitting beam and a receiving beam by using digital beamforming (eg, precoding), analog beamforming (eg, phase rotation), and the like.

[0162] The sending and receiving unit 120 (sending processing unit 1211) may also perform Packet Data Convergence Protocol (PDCP) layer processing, Radio Link Control (RLC) layer processing (for example, RLC retransmission control), Medium Access Control (MAC) layer processing (for example, HARQ retransmission control), etc. on the data and control information obtained from the control unit 110, and generate a bit string to be sent.

[0163] The transmitting and receiving unit 120 (transmitting processing unit 1211) may also perform channel coding (which may also include error correction coding), modulation, mapping, filter 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.

[0164] 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 .

[0165] On the other hand, the transmitting and receiving unit 120 (RF unit 122 ) may also perform amplification, filter processing, demodulation to a baseband signal, etc. on the signal in the radio frequency band received by the transmitting and receiving antenna 130 .

[0166] The sending and receiving unit 120 (receiving processing unit 1212) can also apply 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, and obtain user data, etc.

[0167] The transmitting and receiving unit 120 (measuring unit 123) may also implement measurements related to the received signal. For example, the measuring unit 123 may perform radio resource management (Radio Resource Management (RRM)) measurement, channel state information (CSI) measurement, etc. based on the received signal. The measuring unit 123 may also measure received power (e.g., reference signal received power (Reference Signal Received Power (RSRP))), received quality (e.g., reference signal received quality (Reference Signal Received Quality (RSRQ)), signal to interference plus noise ratio (Signal to Interference plus Noise Ratio (SINR)), signal to noise ratio (Signal to Noise Ratio (SNR))), signal strength (e.g., received signal strength indicator (ReceivedSignal Strength Indicator (RSSI))), propagation path information (e.g., CSI), etc. The measurement result may also be output to the control unit 110.

[0168] The transmission path interface 140 may also send and receive signals (backhaul signaling) between devices included in the core network 30 , other base stations 10 , etc., and acquire and transmit user data (user plane data) and control plane data for the user terminal 20 .

[0169] 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 .

[0170] In addition, the transmitting and receiving unit 120 may also transmit to the user terminal 20 Radio Resource Control (RRC) parameters associated with Beam Failure Recovery (BFR) based on a Medium Access Control Control Element (MAC CE).

[0171] The control unit 110 may also assume that the user terminal 20 determines the BFR to be applied in a certain cell from the BFR based on the random access channel (Physical Random Access Channel (PRACH)) and the BFR based on the MACCE based on the RRC parameters.

[0172] (User Terminal)

[0173] Figure 7 2 is a diagram showing an example of a configuration of a user terminal according to an embodiment. The user terminal 20 includes a control unit 210, a transmission / reception unit 220, and a transmission / reception antenna 230. In addition, the control unit 210, the transmission / reception unit 220, and the transmission / reception antenna 230 may each include more than one.

[0174] In addition, in this example, the functional blocks of the characteristic parts in this embodiment are mainly shown, and it is also conceivable 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.

[0175] 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 the present disclosure relates.

[0176] 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 sent as signals, and forward them to the transmission and reception unit 220.

[0177] The transmitting and receiving unit 220 may also include a baseband unit 221, an RF unit 222, and a measuring unit 223. The baseband unit 221 may also include a transmitting processing unit 2211 and a receiving processing unit 2212. The transmitting and receiving unit 220 may be composed of a transmitter / receiver, an RF circuit, a baseband circuit, a filter, a phase shifter, a measuring circuit, a transmitting and receiving circuit, etc., which are explained based on the common knowledge in the technical field involved in the present disclosure.

[0178] The transmitting and receiving unit 220 may be configured as an integrated transmitting and receiving unit, or may be configured by a transmitting unit and a receiving unit. The transmitting unit may also be configured by a transmitting processing unit 2211 and an RF unit 222. The receiving unit may also be configured by a receiving processing unit 2212, an RF unit 222, and a measuring unit 223.

[0179] The transmitting / receiving antenna 230 can be constituted by an antenna such as an array antenna, which is described based on the common knowledge in the technical field to which the present disclosure relates.

[0180] The transmitting and receiving unit 220 may also receive the above-mentioned downlink channel, synchronization signal, downlink reference signal, etc. The transmitting and receiving unit 220 may also transmit the above-mentioned uplink channel, uplink reference signal, etc.

[0181] The transmitting and receiving unit 220 may also form at least one of a transmitting beam and a receiving beam by using digital beamforming (eg, precoding), analog beamforming (eg, phase rotation), and the like.

[0182] The sending and receiving unit 220 (sending processing unit 2211) may 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, and generate a bit string to be sent.

[0183] 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.

[0184] In addition, whether to apply DFT processing may also be based on the setting of transform precoding. When transform precoding is enabled for a certain channel (e.g., PUSCH), the transmitting and receiving unit 220 (transmitting processing unit 2211) may perform DFT processing as the above-mentioned transmission processing in order to transmit the channel using a DFT-s-OFDM waveform. Otherwise, DFT processing may not be performed as the above-mentioned transmission processing.

[0185] 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 .

[0186] On the other hand, the transmitting and receiving unit 220 (RF unit 222) may also perform amplification, filter processing, demodulation to a baseband signal, etc. on the signal in the radio frequency band received by the transmitting and receiving antenna 230.

[0187] The sending and receiving unit 220 (receiving processing unit 2212) can also perform 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 on the obtained baseband signal, and obtain user data, etc.

[0188] The transmitting and receiving unit 220 (measuring unit 223) may also perform measurements related to the received signal. For example, the measuring unit 223 may also perform RRM measurement, CSI measurement, etc. based on the received signal. 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 result may also be output to the control unit 210.

[0189] 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 .

[0190] In addition, the control unit 210 may also determine the BFR to be applied in a certain cell from the BFR based on the random access channel (Physical Random Access Channel (PRACH)) and the BFR based on the MAC CE, based on the Radio Resource Control (RRC) parameters associated with the Beam Failure Recovery (BFR) based on the Medium Access Control Control Element (MAC CE). Here, the cell may be a primary cell, a primary secondary cell, or a secondary cell.

[0191] The transmitting and receiving unit 220 may also transmit the BFR for the decision when the BF is detected in the cell. The transmission for the BFR may also be for PRACH-based BFR, PRACH transmission for BFRQ, etc. If it is MAC CE-based BFR, the transmission for the BFR may also be the transmission of BFR SR / BFR MAC CE.

[0192] The transmitting and receiving unit 220 may also perform the transmission for the BFR in a cell different from the cell.

[0193] The transmitting and receiving unit 220 may also apply a spatial domain filter corresponding to the detected new candidate beam in the cell to perform transmission for the BFR.

[0194] (Hardware Structure)

[0195] In addition, the block diagram used in the description of the above-mentioned embodiment shows a block of a functional unit. 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 using one device that is physically or logically combined, or two or more devices that are physically or logically separated can be directly or indirectly (for example, using wired, wireless, etc.) connected and implemented using these multiple devices. The functional block can also be implemented by combining software with the above-mentioned one device or the above-mentioned multiple devices.

[0196] Here, the functions include: judging, deciding, determining, calculating, calculating, processing, deriving, investigating, searching, confirming, receiving, sending, outputting, accessing, solving, selecting, selecting, establishing, comparing, assuming, expecting, considering, broadcasting, notifying, communicating, forwarding, configuring, reconfiguring, allocating, mapping, assigning, etc., but are not limited to these. For example, a functional block (structural unit) that plays a role in sending can also be called a transmitting unit, a transmitter, etc. No matter which one it is, as mentioned above, its implementation method is not particularly limited.

[0197] For example, a base station, a user terminal, etc. in one embodiment of the present disclosure may function as a computer that performs processing of the wireless communication method of the present disclosure. Figure 8 The base station 10 and the user terminal 20 may 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, and a bus 1007.

[0198] In addition, in the present disclosure, the terms such as device, circuit, equipment, section, and unit are interchangeable. The hardware configuration of the base station 10 and the user terminal 20 may include one or more of the devices shown in the figure, or may exclude some of the devices.

[0199] For example, only one processor 1001 is shown, but there may be multiple processors. In addition, the processing may be performed by one processor, or the processing may be performed by two or more processors simultaneously, sequentially, or using other methods. In addition, the processor 1001 may also be implemented by one or more chips.

[0200] The various functions in the base station 10 and the user terminal 20 are implemented, for example, in the following manner: 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.

[0201] The processor 1001 controls the entire computer by, for example, operating an operating system. The processor 1001 may be composed of a central processing unit (CPU) including an interface with peripheral devices, a control device, an arithmetic device, a register, etc. For example, at least a part of the control unit 110 (210), the sending and receiving unit 120 (220), etc. may also be implemented by the processor 1001.

[0202] 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 execute at least a part of the operations described in the above embodiments is used. For example, the control unit 110 (210) can be implemented by a control program stored in the memory 1002 and operated in the processor 1001, and other functional blocks can also be implemented in the same way.

[0203] The memory 1002 is a computer-readable recording medium, and may be composed of at least one of a read-only memory (ROM), an erasable programmable ROM (EPROM), an electrically EPROM (EEPROM), a random access memory (RAM), or other suitable storage media. 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 an executable program (program code), a software module, etc. for implementing the wireless communication method involved in one embodiment of the present disclosure.

[0204] The storage 1003 is a computer-readable recording medium, and may be composed of, for example, a flexible disk, a floppy (registered trademark) disk, an optical disk (e.g., a compact disk (Compact Disc ROM (CD-ROM)), a digital versatile disk, a Blu-ray (registered trademark) disk), a removable disk, a hard disk drive, a smart card, a flash memory device (e.g., a card, a stick, a key drive), a magnetic stripe, a database, a server, or at least one of other appropriate storage media. The storage 1003 may also be referred to as an auxiliary storage device.

[0205] The communication device 1004 is hardware (transmitting and receiving device) for communicating between computers via at least one of a wired network and a wireless network, and is also called a network device, a network controller, a network card, a communication module, etc. The communication device 1004 may be configured to include a high-frequency switch, a duplexer, a filter, a frequency synthesizer, etc., for example, in order to realize at least one of frequency division duplex (FDD: Frequency Division Duplex) and time division duplex (TDD: Time Division Duplex). For example, the above-mentioned transmitting and receiving unit 120 (220), the transmitting and receiving antenna 120 (230), etc. may also be realized by the communication device 1004. The transmitting and receiving unit 120 (220) may also be physically or logically separated by the transmitting unit 120a (220a) and the receiving unit 120b (220b).

[0206] The input device 1005 is an input device that receives input from the outside (e.g., a keyboard, a mouse, a microphone, a switch, a button, a sensor, etc.). The output device 1006 is an output device that implements output to the outside (e.g., a display, a speaker, a light emitting diode (LED) lamp, etc.). In addition, the input device 1005 and the output device 1006 may also be an integrated structure (e.g., a touch panel).

[0207] In addition, the processor 1001, the memory 1002 and other devices are connected via a bus 1007 for information communication. The bus 1007 may be configured using a single bus or different buses between the devices.

[0208] In addition, the base station 10 and the user terminal 20 may include hardware such as a microprocessor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a programmable logic device (PLD), and a field programmable gate array (FPGA), and may also use the hardware to implement a part or all of each functional block. For example, the processor 1001 may be implemented using at least one of these hardware.

[0209] (Variation Example)

[0210] In addition, the terms described in the present disclosure and the terms required for understanding the present disclosure can be replaced with terms having the same or similar meanings. For example, channels, code elements, and signals (signal or signaling) can also be replaced with each other. In addition, a signal can also be a message. A reference signal can also be referred to as RS, and depending on the applied standard, it can also be referred to as a pilot, a pilot signal, etc. In addition, a component carrier (CC) can also be referred to as a cell, a frequency carrier, a carrier frequency, etc.

[0211] A wireless frame may also be composed of one or more periods (frames) in the time domain. The one or more periods (frames) constituting a wireless frame may also be referred to as a subframe. Further, a subframe may also be composed of one or more time slots in the time domain. A subframe may be a fixed duration (e.g., 1 ms) that is independent of a parameter set (numerology).

[0212] Here, the parameter set may also be a communication parameter applied to at least one of the transmission and reception of a certain signal or channel. The parameter set may also represent, for example, at least one of a subcarrier spacing (SCS), bandwidth, symbol length, cyclic prefix length, transmission time interval (TTI), the number of symbols per TTI, a wireless frame structure, a specific filtering process performed by a transmitter and receiver in the frequency domain, a specific windowing process performed by a transmitter and receiver in the time domain, and the like.

[0213] 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.

[0214] A time slot may also include multiple mini-slots. Each mini-slot may be composed of one or more symbols in the time domain. In addition, a mini-slot may also be referred to as a sub-slot. A mini-slot may also be composed of a smaller number of 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 a PDSCH (PUSCH) mapping type A. A PDSCH (or PUSCH) transmitted using a mini-slot may also be referred to as a PDSCH (PUSCH) mapping type B.

[0215] Radio frames, subframes, time slots, mini-time slots, and symbols all represent time units for transmitting signals. Radio frames, subframes, time slots, mini-time slots, and symbols may also be referred to by other names corresponding to each other. In addition, time units such as frames, subframes, time slots, mini-time slots, and symbols in the present disclosure may also be interchangeable.

[0216] For example, one subframe may be referred to as a TTI, multiple consecutive subframes may be referred to as a TTI, and one time slot or one mini-time slot may be referred to as a TTI. That is, at least one of a subframe and a TTI may be a subframe (1 ms) in the existing LTE, a period shorter than 1 ms (for example, 1-13 symbols), or a period longer than 1 ms. In addition, the unit representing a TTI may be referred to as a time slot, a mini-time slot, etc. instead of a subframe.

[0217] Here, TTI refers to, for example, the minimum time unit for scheduling in wireless communication. For example, in the LTE system, the base station schedules each user terminal to allocate wireless resources (frequency bandwidth, transmission power, etc. that can be used in each user terminal) in units of TTI. In addition, the definition of TTI is not limited to this.

[0218] TTI can be a transmission time unit for data packets (transmission blocks), code blocks, code words, etc. after channel coding, and can also be a processing unit for scheduling, link adaptation, etc. In addition, when TTI is given, the time interval (e.g., the number of symbols) to which the transmission block, code block, code word, etc. is actually mapped can be shorter than the TTI.

[0219] In addition, when 1 time slot or 1 mini time slot is called TTI, more than 1 TTI (i.e., more than 1 time slot or more than 1 mini time slot) can be the minimum time unit of scheduling. In addition, the number of time slots (number of mini time slots) constituting the minimum time unit of scheduling can also be controlled.

[0220] A TTI with a duration of 1 ms may also be referred to as a normal TTI (TTI in 3GPP Rel.8-12), a normal TTI, a long TTI, a normal subframe, a normal subframe, a long subframe, a time slot, etc. A TTI shorter than a normal TTI may also be referred to as a shortened TTI, a short TTI, a partial or fractional TTI, a shortened subframe, a short subframe, a mini-time slot, a sub-time slot, a time slot, etc.

[0221] In addition, long TTI (e.g., normal TTI, subframe, etc.) can also be replaced by a TTI with a duration exceeding 1 ms, and short TTI (e.g., shortened TTI, etc.) can also be replaced by a TTI with a TTI length shorter than that of long TTI and longer than 1 ms.

[0222] A resource block (RB) is a resource allocation unit in the time domain and the frequency domain. In the frequency domain, it may also include one or more consecutive subcarriers (subcarriers). The number of subcarriers included in an RB may also 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.

[0223] In addition, an RB may include one or more symbols in the time domain, and may be the length of one slot, one mini slot, one subframe, or one TTI. One TTI, one subframe, etc. may also be composed of one or more resource blocks, respectively.

[0224] In addition, one or more RBs may also be referred to as a physical resource block (physical RB (PRB)), a sub-carrier group (SCG), a resource element group (REG), a PRB pair, an RB pair, etc.

[0225] In addition, a resource block may be composed of one or more resource elements (RE). For example, one RE may be a radio resource region of one subcarrier and one symbol.

[0226] A Bandwidth Part (BWP) (also referred to as a partial bandwidth, etc.) may also represent a subset of contiguous common RBs (common resource blocks) for a parameter set in a carrier. Here, a common RB may also be identified by an index of the RB based on a common reference point of the carrier. PRBs may also be defined in a BWP and numbered within the BWP.

[0227] 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 in one carrier.

[0228] At least one of the configured BWPs may be activated, and the UE may not assume that a specific signal / channel is transmitted or received outside the activated BWP. In addition, "cell", "carrier", etc. in the present disclosure may be replaced by "BWP".

[0229] In addition, the structures of the radio frame, subframe, time slot, mini-time slot and symbol mentioned above are only examples. For example, the number of subframes included in the radio frame, the number of time slots in each subframe or radio frame, the number of mini-time slots included in the time slot, the number of symbols and RBs included in the time slot or mini-time slot, the number of subcarriers included in the RB, the number of symbols in the TTI, the symbol length, the cyclic prefix (CP) length and other structures can be changed in various ways.

[0230] In addition, the information, parameters, etc. described in the present disclosure may be represented by absolute values, relative values ​​relative to a specific value, or other corresponding information. For example, wireless resources may also be indicated by a specific index.

[0231] The names used for parameters, etc. in this disclosure are not limiting in any way. Furthermore, the mathematical formulas, etc. using these parameters may also be different from the mathematical formulas explicitly disclosed in this disclosure. Various channels (PUCCH, PDCCH, etc.) and information elements can be identified by all appropriate names, and thus the various names assigned to these various channels and information elements are not limiting in any way.

[0232] Information, signals, etc. described in this disclosure may be represented using any of a variety of different technologies. For example, data, instructions, commands, information, signals, bits, code elements, and chips, etc. mentioned throughout the above description may also be represented by voltage, current, electromagnetic waves, magnetic fields or magnetic particles, light fields or photons, or any combination thereof.

[0233] In addition, information, signals, etc. may be output in at least one direction from a high layer to a low layer, and from a low layer to a high layer. Information, signals, etc. may also be input and output via multiple network nodes.

[0234] The input and output information, signals, etc. may be stored in a specific area (e.g., a memory) or managed using a management table. The input and output information, signals, etc. may also be overwritten, updated, or recorded. The output information, signals, etc. may also be deleted. The input information, signals, etc. may also be sent to other devices.

[0235] The notification of information is not limited to the method / implementation method described in the present disclosure, and other methods may also be used. For example, the notification of information in the present disclosure may 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.

[0236] In addition, physical layer signaling may also be referred to as layer 1 / layer 2 (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 an RRC message, for example, an RRC connection setup (RRC Connection Setup) message, an RRC connection reconstruction (RRC Connection Reconfiguration) message, etc. In addition, MAC signaling may also be notified using, for example, a MAC Control Element (CE).

[0237] Furthermore, notification of specific information (for example, notification of “it is X”) is not limited to explicit notification, but may be performed implicitly (for example, by not notifying the specific information or by notifying other information).

[0238] The determination may be made by a value represented by one bit (0 or 1), by a true or false value (boolean) represented by true (true) or false (false), or by comparison of numerical values ​​(for example, comparison with a specific value).

[0239] Software, whether referred to as software, firmware, middleware, microcode, hardware description language, or by other names, shall be construed broadly to mean instructions, instruction sets, codes, code segments, program code, programs, subroutines, software modules, applications, software applications, software packages, routines, subroutines, objects, executables, execution threads, procedures, functions, etc.

[0240] In addition, software, instructions, information, etc. may be sent and received via a transmission medium. For example, when the software is sent from a website, server, or other remote source using at least one of wired technology (coaxial cable, optical cable, twisted pair, and Digital Subscriber Line (DSL)), etc.) and wireless technology (infrared, microwave, etc.), at least one of these wired technology and wireless technology is included in the definition of transmission medium.

[0241] The terms "system" and "network" used in the present disclosure may be used interchangeably. "Network" may also refer to a device included in the network (eg, a base station).

[0242] 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" may also be used interchangeably.

[0243] In the present disclosure, the terms "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", "component carrier" and the like are used interchangeably. The base station may also be referred to as a macro cell, a small cell, a micro cell, a pico cell and the like.

[0244] 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, and each smaller area can also provide communication services through a base station subsystem (for example, a small base station for indoor use (Remote Radio Head (RRH))). Terms such as "cell" or "sector" refer to a part or all of the coverage area of ​​at least one of a base station and a base station subsystem that provide communication services within the coverage area.

[0245] In the present disclosure, terms such as “mobile station (MS)”, “user terminal”, “user equipment (UE)”, and “terminal” may be used interchangeably.

[0246] A mobile station may also be referred to as a subscriber station, a mobile unit, a subscriber unit, a wireless unit, a remote unit, a mobile device, a wireless device, a wireless communication device, a remote device, a mobile subscriber station, an access terminal, a mobile terminal, a wireless terminal, a remote terminal, a handheld device, a user agent, a mobile client, a client, or some other appropriate terminology.

[0247] 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. In addition, at least one of the base station and the mobile station may also be a device mounted on a mobile body, the mobile body itself, etc. The mobile body may also be a means of transportation (e.g., a car, an airplane, etc.), a mobile body that moves in an unmanned manner (e.g., a drone, an autonomous vehicle, etc.), or a robot (manned or unmanned). In addition, at least one of the base station and the mobile station also includes a device that does not necessarily move during communication operations. For example, at least one of the base station and the mobile station may also be an Internet of Things (IoT) device such as a sensor.

[0248] 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 the communication between multiple user terminals (for example, may also be referred to as device-to-device (D2D)), vehicle-to-everything (V2X), etc.). In this case, the user terminal 20 may be configured to have the functions of the above-mentioned base station 10. In addition, words such as "uplink" and "downlink" may also be replaced by words corresponding to communication between terminals (for example, "side". For example, an uplink channel, a downlink channel, etc. may also be replaced by a side channel.

[0249] Likewise, the user terminal in the present disclosure may be replaced by a base station. In this case, the base station 10 may be configured to have the functions of the user terminal 20 described above.

[0250] In the present disclosure, with respect to operations set to be performed by a base station, sometimes, depending on the circumstances, they are also performed by its upper node. In a network including one or more network nodes having a base station, various operations performed for communication with a terminal can obviously be performed by a base station, one or more network nodes other than the base station (for example, consider a Mobility Management Entity (MME)), a Serving-Gateway (S-GW), etc., but not limited thereto), or a combination thereof.

[0251] Each method / implementation method described in this disclosure may be used alone, in combination, or switched during execution. In addition, the processing procedures, timings, flow charts, etc. of each method / implementation method described in this disclosure may be swapped in order as long as they are not contradictory. For example, with respect to the method described in this disclosure, the elements of various steps are presented in an illustrative order, and are not limited to the specific order presented.

[0252] The various modes and embodiments described in the present disclosure can 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 (Ultra Mobile Broadband (UMB)), IEEE 802.11 (Wi-Fi (registered trademark)), IEEE 802.16 (WiMAX (registered trademark)), IEEE 802.20, Ultra-WideBand (UWB), Bluetooth (registered trademark), and systems using other appropriate wireless communication methods, and next-generation systems expanded based on them. In addition, multiple systems can also be applied in combination (for example, LTE or LTE-A, combination with 5G, etc.).

[0253] The phrase “based on” used in the present disclosure does not mean “based only on” unless explicitly described otherwise. In other words, the phrase “based on” means both “based only on” and “based at least on”.

[0254] Any reference to an element using the terms "first," "second," etc., used in this disclosure is not intended to be a comprehensive limitation on the number or order of these elements. These terms may be used in this disclosure as a convenient method of distinguishing between two or more elements. Therefore, reference to a first and second element does not mean that only two elements may be used or that the first element must be located before the second element in some form.

[0255] The term "determining" as used in this disclosure sometimes includes a variety of operations. For example, "determining" can be considered to be "judging", calculating, computing, processing, deriving, investigating, looking up, searching, inquiring (e.g., searching in a table, database or other data structure), ascertaining, etc.

[0256] In addition, "judgment (decision)" can also be regarded as "judgment (decision)" on receiving (e.g., receiving information), transmitting (e.g., sending information), input (input), output (output), accessing (e.g., accessing data in a memory), etc.

[0257] In addition, "judgment (decision)" can also be regarded as "judgment (decision)" on resolving (resolving), selecting (selecting), choosing (choosing), establishing (establishing), comparing (comparing), etc. That is, "judgment (decision)" can be regarded as "judgment (decision)" on certain operations.

[0258] In addition, "judge (decide)" can also be replaced by "assuming (assuming)", "expecting (expecting)", "considering (considering)" and so on.

[0259] The “maximum transmit power” recorded in the present disclosure may refer to 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).

[0260] The terms "connected", "coupled", or all their variations used in this disclosure mean all direct or indirect connections or couplings between two or more elements, and can include the situation where there are one or more intermediate elements between the two elements that are "connected" or "coupled" to each other. The combination or connection between the elements can be physical, logical, or a combination thereof. For example, "connection" can also be replaced by "access".

[0261] In the present disclosure, when two elements are connected, it can be considered that they are "connected" or "combined" to each other using one or more wires, cables, printed electrical connections, etc., and as some non-limiting and non-exhaustive examples, they are "connected" or "combined" to each other using electromagnetic energy with a wavelength in the wireless frequency domain, microwave region, light (both visible and invisible light) region, etc.

[0262] In the present disclosure, the term "A is different from B" may also mean "A and B are different from each other". In addition, the term may also mean "A and B are different from C, respectively". The terms "separate" and "bound" may also be interpreted in the same way as "different".

[0263] When the terms "include," "including," and variations thereof are used in this disclosure, these terms are intended to be inclusive, similar to the term "comprising." Further, the term "or" as used in this disclosure does not constitute an exclusive logical or.

[0264] In the present disclosure, when an article is added due to translation, such as a, an, and the in English, the present disclosure may also include a case where the noun connected to the article is in plural form.

[0265] The invention disclosed herein is described in detail above, but it is obvious to those skilled in the art that the invention disclosed herein is not limited to the embodiments described in the disclosure. The invention disclosed herein can be implemented as a modification and alteration without departing from the purpose and scope of the invention determined by the description of the claims. Therefore, the description of the disclosure is for the purpose of illustration and does not bring any restrictive meaning to the invention disclosed herein.

Claims

1. A terminal having: a control unit that, when a radio resource control parameter (RRC parameter) related to validation of a MAC CE-based beam failure recovery BFR according to a medium access control element (MAC CE) is set, applies the MAC CE-based BFR in a primary cell, and, when the RRC parameter is not set, applies a PRACH-based BFR according to a random access channel (Physical Random Access Channel (PRACH)) in the primary cell; and The transmitting unit transmits the BFR to be applied when a beam failure is detected in the primary cell.

2. The terminal according to claim 1, wherein: The sending unit sends capability information indicating that the terminal supports the MAC CE-based BFR.

3. A wireless communication method of a terminal, comprising: In a case where a radio resource control parameter (RRC parameter) related to validation of MAC CE-based beam failure recovery BFR according to a medium access control element MAC CE is set, the MAC CE-based BFR is applied in the primary cell, and in a case where the RRC parameter is not set, a PRACH-based BFR according to a random access channel (Physical Random Access Channel PRACH) is applied in the primary cell; and In case a beam failure is detected in the primary cell, a step of transmitting the applied BFR is performed.

4. A base station, comprising: a control unit, wherein, when a radio resource control parameter (RRC parameter) related to validation of a MAC CE-based beam failure recovery BFR according to a media access control element MAC CE is set for a terminal, it is assumed that the terminal applies the MAC CE-based BFR in a primary cell; and when the RRC parameter is not set for the terminal, it is assumed that the terminal applies a PRACH-based BFR according to a random access channel (Physical Random Access Channel PRACH) in the primary cell, The receiving unit receives the BFR for the terminal application.

5. A system comprising a terminal and a base station, The terminal has: a control unit, wherein, when a radio resource control parameter (RRC parameter) related to validation of a MAC CE-based beam failure recovery BFR according to a medium access control element (MAC CE) is set, the MAC CE-based BFR is applied in the primary cell, and when the RRC parameter is not set, the PRACH-based BFR is applied according to a random access channel (Physical Random Access Channel (PRACH)) in the primary cell; as well as a transmitting unit, which, when a beam failure is detected in the primary cell, transmits the BFR used for application, The base station has: a control unit, which, when the RRC parameter is set for the terminal, assumes that the terminal applies the MAC CE-based BFR in the primary cell; and, when the RRC parameter is not set for the terminal, assumes that the terminal applies the PRACH-based BFR in the primary cell; as well as The receiving unit receives the BFR for the terminal application.

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