User terminal and wireless communication method

Abstract

One method of a user terminal disclosed in the present invention comprises: a sending unit, which sends information related to a new candidate beam when a beam failure of a specific cell is detected; and a control unit, which uses a specific reference signal as a reference signal for the new candidate beam when a reference signal for the new candidate beam is not set.

Description

Technical Field

[0001] The present disclosure relates to a user terminal and a wireless communication method 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 rate, low latency, etc. (Non-Patent Document 1). In addition, LTE-Advanced (3GPP Rel. 10-14) is standardized for the purpose of further increasing the capacity and sophistication of LTE (Release (Rel.) 8, 9 of the Third Generation Partnership Project (3GPP)).

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

[0004] In the existing LTE system (LTE Rel.8-14), radio link quality is monitored (Radio Link Monitoring (RLM)). If a radio link failure (RLF) is detected by RLM, the user terminal (User Equipment (UE)) is requested to re-establish an RRC (Radio Resource Control) connection.

[0005] Prior art literature

[0006] Non-patent literature

[0007] 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

[0008] Problems to be solved by the invention

[0009] In future wireless communication systems (e.g., NR), a process of switching to another beam upon detecting a beam failure (Beam Failure: BF) (also referred to as a beam failure recovery (Beam Failure Recovery: BFR) process, BFR, etc.) is being studied and implemented. In addition, in the BFR process, when a beam failure occurs, the UE reports a beam failure recovery request (Beam Failure Recovery reQuest: BFRQ) requesting recovery of the beam failure.

[0010] In addition, a study is underway to allow the UE to report information related to a new candidate beam (also referred to as a new candidate beam) during the BFR process. The network (eg, base station) can appropriately recover from beam failure by newly configuring the new candidate beam reported from the UE.

[0011] However, in the BFR process, there has been insufficient research on how to set reference signals for new candidate beams, etc. If the BFR process cannot be performed properly, there is a concern that BFR delays may occur, which may degrade system performance.

[0012] Therefore, one of the objectives of the present disclosure is to provide a user terminal and a wireless communication method for appropriately performing a BFR process.

[0013] Means for solving problems

[0014] A user terminal involved in one embodiment of the present invention is characterized in that it has: a sending unit that sends information related to a new candidate beam when a beam failure of a specific cell is detected; and a control unit that uses a specific reference signal as a reference signal for the new candidate beam when a reference signal for the new candidate beam is not set.

[0015] Effects of the Invention

[0016] According to one embodiment of the present disclosure, the BFR process can be appropriately performed. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0018] Figure 2 This is a diagram for explaining intra-band CA and inter-band CA.

[0019] Figure 3 This is a diagram showing an example of setting or selecting RS for new candidate beams.

[0020] Figure 4 This is a diagram showing another example of setting or selecting RS for new candidate beams.

[0021] Figure 5 This is a diagram showing another example of setting or selecting RS for new candidate beams.

[0022] Figure 6 This is a diagram showing an example of a schematic configuration of a wireless communication system according to an embodiment.

[0023] Figure 7 This is a diagram showing an example of the structure of a base station involved in one embodiment.

[0024] Figure 8 This is a diagram showing an example of a configuration of a user terminal according to an embodiment.

[0025] Fig. 9 This is a diagram showing an example of the hardware configuration of a base station and a user terminal according to an embodiment. DETAILED DESCRIPTION

[0026] <Beam Failure Recovery>

[0027] In NR, the use of beamforming for communication is being studied. For example, UE and base station (e.g., gNodeB (gNB)) can also use beams for sending signals (also called transmit beams, Tx beams, etc.) and beams for receiving signals (also called receive beams, Rx beams, etc.).

[0028] When beamforming is used, it is assumed that the radio link quality will deteriorate because it is easily affected by obstacles. Due to the deterioration of the radio link quality, there is a concern that radio link failures (RLF) will frequently occur. If RLF occurs, the cell needs to be reconnected, so frequent RLFs will lead to degradation of system throughput.

[0029] In NR, in order to suppress the occurrence of RLF, a process of switching to other beams (also called beam recovery (BR), beam failure recovery (BFR), L1 / L2 (Layer 1 / Layer 2) beam recovery, etc.) is being studied when the quality of a specific beam deteriorates. In addition, the BFR process can also be referred to as BFR.

[0030] 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).

[0031] Figure 1 This is a diagram showing an example of the beam recovery process in Rel.15NR. The number of beams is just 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 transmitted using two beams.

[0032] The RS may be at least one of a synchronization signal block (SSB) and a channel state measurement RS (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.

[0033] 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 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)), etc.

[0034] 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 be caused by obstacles, fading, interference, etc. between the UE and the base station.

[0035] If a specific condition is met, the UE detects a beam failure. For example, the UE may detect the occurrence of a beam failure when the block error rate (BLER) is less than a threshold for all configured BFD-RS (BFD-RS resource configuration). If a beam failure is detected, the lower layer (physical (PHY) layer) of the UE may also notify (indicate) the higher layer (MAC layer) of the beam failure instance.

[0036] In addition, the criterion for judgment is not limited to BLER, but may also be the reference signal received power in the physical layer (Layer 1 Reference Signal Received Power (L1-RSRP)). Furthermore, beam failure detection may be performed based on a downlink control channel (Physical Downlink Control Channel (PDCCH)) instead of RS measurement or in addition to RS measurement. Regarding BFD-RS, it can also be envisioned as quasi-co-location (QCL) with the DMRS of the PDCCH monitored by the UE.

[0037] Here, the so-called QCL refers to 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 be indicated that it can be assumed that at least one of the Doppler shift, Doppler spread, average delay, delay spread, and spatial parameter (for example, spatial receive filter / parameter, spatial transmit filter / parameter) is the same among these different multiple signals / channels (at least one of these is QCL).

[0038] In addition, the spatial reception parameter may also correspond to the UE's reception beam (e.g., reception analog beam), or the beam may be determined based on the spatial QCL. The QCL (or at least one element in the QCL) in the present disclosure may also be replaced by spatial QCL (sQCL).

[0039] Information related to BFD-RS (e.g., RS index, resource, 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 using high-layer signaling, etc. The information related to BFD-RS can also be referred to as information related to BFR resources, etc.

[0040] In the present disclosure, the high-layer signaling may be, for example, Radio Resource Control (RRC) signaling, Medium Access Control (MAC) signaling, broadcast information, or a combination thereof.

[0041] MAC signaling may use, for example, MAC Control Element (CE), MAC Protocol Data Unit (PDU), etc. Broadcast information may include, for example, Master Information Block (MIB), System Information Block (SIB), Remaining Minimum System Information (RMSI), Other System Information (OSI), etc.

[0042] 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 one of the random access procedures described later) after receiving a certain number of beam failure instance notifications (e.g., beam Failure Instance Max Count set by RRC) or more before the expiration of the timer.

[0043] 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.

[0044] In step S103, the UE starts searching for a new candidate beam (new candidate beam) for communication in order to recover the beam. 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 identifying a new candidate beam (new candidate beam identifier RS ​​(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.

[0045] 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 criterion for judgment is not limited to L1-RSRP. At least one of L1-RSRP, L1-RSRQ, and L1-SINR (signal-to-noise interference power ratio) may also be used for determination. 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.

[0046] Information related to NCBI-RS (e.g., RS resources, quantity, number of ports, precoding, etc.), information related to new candidate beam identifier (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.

[0047] In addition, BFD-RS, NCBI-RS, etc. can also be replaced by a radio link monitoring reference signal (RLM-RS: Radio Link Monitoring RS).

[0048] In step S104, the UE that has determined the new candidate beam sends a beam restoration request (Beam Failure Recovery request (BFRQ)). The beam restoration request may also be called a beam restoration request signal, a beam failure recovery request signal, or the like.

[0049] For example, BFRQ can also be sent using at least one of the uplink control channel (Physical Uplink Control Channel (PUCCH)), random access channel (Physical Random Access Channel (PRACH)), uplink shared channel (Physical Uplink Shared Channel (PUSCH)), configured grant PUSCH, and MAC CE.

[0050] The BFRQ may also include information about the new candidate beam determined in step S103. Resources for the BFRQ may also be associated with the new candidate beam. The beam information may also be notified using a beam index (Beam Index: BI), a port index of a specific reference signal, a resource index (e.g., a CSI-RS resource indicator (CSI-RS Resource Indicator: CRI), an SSB resource indicator (SSBRI)), etc.

[0051] In Rel.15NR, research is underway on BFR based on contention-based random access (Random Access: RA) procedures, namely CB-BFR (Contention-Based BFR) and BFR based on non-contention-based random access procedures, namely CF-BFR (Contention-Free BFR). In CB-BFR and CF-BFR, UE can also use PRACH resources to send preambles (also called RA preambles, random access channels (Physical Random Access Channel: PRACH), RACH preambles, etc.) as BFRQ.

[0052] In addition, in NR, multiple PRACH formats (PRACH preamble formats) are being studied. The random access (RA) preamble using each PRACH format includes a RACH OFDM symbol. Furthermore, the RA preamble may also include at least one of a cyclic prefix (CP) and a guard period (GP). For example, PRACH formats 0 to 3 use a long sequence preamble sequence in the RACH OFDM symbol. PRACH formats A1 to A3, B1 to B4, C0, and C2 use a short sequence preamble sequence in the RACH OFDM symbol.

[0053] The frequency of the carrier may be within one of the frequency ranges (Frequency Range (FR)) 1 and FR2. FR1 may be a frequency range lower than a specific frequency, and FR2 may be a frequency range higher than the specific frequency.

[0054] In addition, compared with PRACH, the uplink control channel can set resources more flexibly in the time domain. Therefore, as a channel used for BFRQ transmission, the uplink control channel (PUCCH) is also considered. In addition, compared with PRACH, MAC CE and PUSCH can set resources more flexibly in the time domain. Therefore, as a channel used for BFRQ transmission, the use of MAC CE and PUSCH is also considered.

[0055] In step S105, the base station that detects the BFRQ sends a response signal (also referred to as a gNB response, etc.) to the BFRQ from the UE. The response signal may also include reconstruction information for one or more beams (for example, setting information (structural information) of DL-RS resources).

[0056] The response signal may be sent, for example, in the UE common search space of the 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., 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.

[0057] 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.

[0058] Regarding CB-BFR, when the UE receives the PDCCH corresponding to the C-RNTI related to itself, it can also be determined that contention resolution has succeeded.

[0059] Regarding the processing of step S105, a period for the UE to monitor the response from the base station (e.g., gNB) to the BFRQ may also be set. This period may also be called, for example, a gNB response window, a gNB window, a beam recovery request response window, a BFRQ response window, etc. If there is no detected gNB response during this window, the UE may retransmit the BFRQ.

[0060] In step S106, the UE may also send a message to the base station indicating that the beam reconfiguration is completed. The message may be sent, for example, via the PUCCH or the PUSCH.

[0061] In step S106, the UE may receive RRC signaling indicating the setting of the TCI state for the PDCCH, and may also receive a MAC CE indicating activation of the setting.

[0062] Beam recovery success (BR success) may also indicate, for example, reaching step S106. On the other hand, beam recovery failure (BR failure) may correspond to, for example, BFRQ transmission reaching a specific number of times or the beam failure recovery timer (Beam-failure-recovery-Timer) expiring.

[0063] 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.

[0064] As described above, in the existing LTE system, it is stipulated that BFR is performed only on a specific cell (for example, a primary cell) when communicating using multiple cells. However, in NR, application of the BFR process to multiple cells is being studied.

[0065] As a structure for performing communication using multiple cells, there are, for example, intra-band carrier aggregation (Intra-band CA) and inter-band carrier aggregation (Inter-band CA) (see Figure 2 ).

[0066] exist Figure 2 , a case where a first band #1 and a second band #2 are used as a plurality of frequency bands is shown. In addition, the frequency bands to be applied are not limited to two, and the frequency bands (or frequency domains) may be divided into three or more.

[0067] exist Figure 2 In FIG. 1 , CC#m and CC#n are set in the first band #1, and CC#p and CC#q are set in the second band #2. CA between CC#m and CC#n, or CA between CC#m and CC#n, corresponds to intra-band CA. On the other hand, CA between a CC (e.g., CC#m or CC#n) set in the first band #1 and a CC (e.g., CC#p or CC#q) set in the second band corresponds to inter-band CA.

[0068] In addition, a structure in which the first band corresponds to the first frequency range (FR1) and the second band corresponds to the second frequency range (FR2) may be adopted. 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)).

[0069] FR1 may also be defined as a frequency range using at least one of 15, 30, and 60 kHz as a subcarrier spacing (SCS), and FR2 may also be defined as a frequency range using at least one of 60 and 120 kHz as an SCS. In addition, the frequency bands and definitions of FR1 and FR2 are not limited to these. For example, FR1 may be a higher frequency band than FR2. Cells using FR1 and cells using FR2 may also be configured to apply different parameter sets (Numerology) (e.g., subcarrier spacing, etc.).

[0070] As described above, it is assumed that the BFR process is applied to multiple cells (e.g., SCells). In such a case, it is assumed that a beam failure occurs in a certain cell, and the UE sends a BFRQ to the network (e.g., a base station), determines a new candidate beam, and sends information related to the new candidate beam.

[0071] In order to determine a new candidate beam, the UE needs to measure a specific RS. However, when supporting the BFR process in multiple cells, how to control the setting of the RS used in the determination of the new candidate beam or the method of determining the new candidate beam becomes a problem. For example, when the RS for the new candidate beam is not set, which RS is used to determine the new candidate beam to be reported becomes a problem.

[0072] The inventors of the present invention studied the setting or selection of RS for new candidate beams and came up with the present invention.

[0073] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. The following embodiments may be applied individually or in combination.

[0074] In addition, in the following description, L1-RSRP is cited as an example of a measurement type used for determining a new candidate beam, but the applicable measurement types are not limited to this. In addition, L1-RSRQ and L1-SINR may also be applied, or at least two of L1-RSRP, L1-RSRQ, L1-RSRQ, and L1-SINR may be combined for application.

[0075] In addition, in the following description, the RS for the new candidate beam may be replaced by the RS for determining the new candidate beam, the RS set for determining the new candidate beam, and the new beam identification RS. In addition, in the following description, the set (RS set) or combination of reference signals may be simply replaced by the reference signal (RS), and the reference signal (RS) may be replaced by the set (RS set) or combination of reference signals. In addition, the reference signal (RS) may be replaced by at least one of SSB, CSI-RS, and TRS.

[0076] (First method)

[0077] In the first embodiment, the setting or selection of a new candidate beam RS in the BFR process of a specific cell (for example, SCell) is described.

[0078] For example, at least one of the following situations 1 to 5 may be used to control the setting or selection of a new candidate beam RS.

[0079] <Scenario 1>

[0080] It is also possible to set a structure in which the new candidate beam RS is always set. For example, when the BFR process (e.g., BFD RS) of a specific cell is set, the UE may also assume that the new candidate beam RS is always set in the specific cell (or other cells). The other cell may also be a cell (or CC) belonging to the same band as the specific cell.

[0081] The network (e.g., base station) sets the new candidate beam RS to the UE through high-layer signaling, etc. The UE may also determine that the BFR process is wrong when the new candidate beam RS is not set. In this case, the UE may also send information to the base station indicating that the new candidate beam cannot be grasped.

[0082] In this way, by setting a structure in which the RS for new candidate beams is always set during the BFR process of a specific cell, when a beam failure is detected, information on new candidate beams suitable for the UE can be appropriately reported to the base station based on the measurement results of the RS for new candidate beams.

[0083] In the following scenario 2-6, it is assumed that the new candidate beam RS is not set through higher layer signaling or the like.

[0084] <Scenario 2>

[0085] A beam failure detection RS (BFD RS) may also be applied as a new candidate beam RS. For example, when a BFR process (e.g., BFD RS) of a specific cell is set but a new candidate beam RS is not set, the UE may determine that the new candidate beam RS is the same as the BFD RS.

[0086] <Scenario 3>

[0087] A specific RS corresponding to (or associated with) a control resource set may also be applied as a new candidate beam RS. For example, when a BFR process (e.g., a BFD RS) of a specific cell is set but a new candidate beam RS is not set, the UE recognizes that the new candidate beam RS is a specific RS corresponding to a control resource set set in the cell.

[0088] The specific RS may be, for example, a synchronization signal block (e.g., SSB or SS / PBCH). In addition, the control resource set may be a part of the control resource set set in the cell, or may be all the control resource sets when set. Information related to the association between the control resource set and the specific RS may also be notified to the UE from the base station through at least one of a higher layer signaling and a MAC control signal.

[0089] Therefore, when the BFR process is set, even if the RS for the new candidate beam is not set, the UE can report the information related to the new candidate beam to the base station using the specific RS.

[0090] <Scenario 4>

[0091] A set of specific RSs (or a combination of specific RSs) set in the transmission configuration indication state (Transmission Configuration Indication state (TCI state)) of the downlink channel may also be applied as a new candidate beam RS. For example, when a BFR process (e.g., BFD RS) of a specific cell is set but a new candidate beam RS is not set, the UE may recognize that the new candidate beam RS is a set of specific RSs set in the cell (or other cells).

[0092] The downlink channel may also be at least one of a downlink control channel (e.g., PDCCH) and a downlink shared channel (e.g., PDSCH). The specific RS may also be channel state information (e.g., CSI-RS). In addition, the CSI-RS may also be at least one of a periodic CSI-RS (e.g., P-CSI-RS), an aperiodic CSI-RS (e.g., A-CSI-RS), and a semi-persistent CSI-RS (e.g., SP-CSI-RS).

[0093] In addition, the specific RS may be an RS corresponding to the TCI state of the downlink channel (or an RS set corresponding to the TCI state).

[0094] [TCI Status]

[0095] The so-called TCI state refers to information related to Quasi-Co-Location (QCL) of signals / channels, and may also be called spatial reception parameters, Spatial Relation Information (SRI), etc. The TCI state may also be set for the UE per channel or per signal.

[0096] The so-called QCL refers to an indicator indicating the statistical properties of a signal / channel. For example, when a certain signal / channel is in a QCL relationship with other signals / channels, it can also be indicated that it can be assumed that at least one of the Doppler shift, Doppler spread, average delay, delay spread, and spatial parameter (for example, spatial Rx parameter) is the same among these different multiple signals / channels (at least one of these is QCL).

[0097] In addition, the spatial reception parameter may also correspond to the UE's reception beam (e.g., reception analog beam), or the beam may be determined based on the spatial QCL. The QCL (or at least one element in the QCL) in the present disclosure may also be replaced by sQCL (spatial QCL (sQCL)).

[0098] Regarding QCL, multiple types (QCL types) may also be specified. For example, the following four QCL types AD may be set, in which the parameters (or parameter sets) that can be assumed to be the same are different. The following shows the parameters:

[0099] QCL Type A (QCL-A): Doppler shift, Doppler spread, average delay, and delay spread,

[0100] QCL Type B (QCL-B): Doppler shift and Doppler spread,

[0101] QCL Type C (QCL-C): Doppler shift and average delay,

[0102] QCL type D (QCL-D): spatial reception parameters.

[0103] The UE assumes that a specific Control Resource Set (CORESET), channel or reference signal is in a specific QCL (e.g., QCL type D) relationship with other CORESETs, channels or reference signals, which may also be referred to as QCL assumption.

[0104] The UE may also determine at least one of the transmit beam (Tx beam) and receive beam (Rx beam) of the signal / channel based on the TCI status or QCL assumption of the signal / channel.

[0105] The TCI state may be, for example, information related to the QCL between the channel being the object (in other words, the reference signal (ReferenceSignal(RS)) used by the channel) and other signals (for example, other reference signals (ReferenceSignal(RS))). The TCI state may also be set (indicated) by at least one of higher layer signaling (for example, RRC signaling), medium access control (MediumAccessControl(MAC)) signaling, and physical layer signaling.

[0106] MAC signaling may use, for example, MAC Control Element (MAC CE), MAC Protocol Data Unit (MAC Protocol Data Unit (PDU)), etc. Physical layer signaling may be, for example, downlink control information (Downlink Control Information (DCI)).

[0107] The channel for which the TCI state or spatial relationship is set (specified) may be, for example, at least one of the downlink shared channel (PDSCH), the downlink control channel (PDCCH), the uplink shared channel (PUSCH), and the uplink control channel (PUCCH).

[0108] In addition, the RS that is in a QCL relationship with the channel may be, for example, at least one of a synchronization signal block (SSB), a channel state information reference signal (CSI-RS), a measurement reference signal (Sounding Reference Signal (SRS)), a tracking CSI-RS (also called a tracking reference signal (TRS)), a QCL detection reference signal (also called QRS), etc.

[0109] The information element of the TCI state set by high-level signaling ("TCI-state IE" of RRC) may also include one or more QCL information ("QCL-Info"). The QCL information may also include at least one of information related to the RS that forms a QCL relationship (RS relationship information) and information indicating the QCL type (QCL type information). The RS relationship information may also include information such as the index of the RS (for example, SSB index, non-zero-power CSI-RS (Non-Zero-Power (NZP) CSI-RS) resource ID (identifier)), the index of the cell where the RS is located, and the index of the bandwidth part (Bandwidth Part (BWP)) where the RS is located.

[0110] Alternatively, both the QCL type A RS and the QCL type D RS or only the QCL type A RS may be set to the UE as the TCI state of at least one of the PDCCH and the PDSCH.

[0111] When TRS is set as RS of QCL type A, TRS is different from DMRS of PDCCH or PDSCH, and it is assumed that the same TRS is transmitted periodically for a long time. UE can measure TRS and calculate average delay, delay spread, etc.

[0112] In the TCI state of the DMRS of the PDCCH or PDSCH, the UE in which the TRS is set as the RS of QCL type A can assume that the parameters of QCL type A (average delay, delay spread, etc.) between the DMRS of the PDCCH or PDSCH and the TRS are the same, and thus the parameters of type A (average delay, delay spread, etc.) of the DMRS of the PDCCH or PDSCH can be obtained based on the measurement result of the TRS. The UE can use the measurement result of the TRS when performing channel estimation of at least one of the PDCCH and the PDSCH to perform more accurate channel estimation.

[0113] A UE to which a QCL type D RS is set can determine a UE reception beam (spatial domain reception filter, UE spatial domain reception filter) using the QCL type D RS.

[0114] [TCI status for PDCCH]

[0115] Information related to the QCL between the PDCCH (or the demodulation reference signal (DMRS) antenna port associated with the PDCCH) and a specific RS may also be referred to as the TCI state for the PDCCH, etc.

[0116] The UE may also determine the TCI state for the UE-specific PDCCH (CORESET) based on higher layer signaling. For example, one or more (K) TCI states may be set for each CORESET for the UE through RRC signaling.

[0117] Alternatively, in the UE, for each CORESET, one of the multiple TCI states set by RRC signaling is activated by MAC CE. The MAC CE may also be referred to as TCI State Indication for UE-specific PDCCH MAC CE. The UE may also monitor the CORESET based on the activated TCI state corresponding to the CORESET.

[0118] [TCI status for PDSCH]

[0119] Information related to the QCL between the PDSCH (or the DMRS antenna port associated with the PDSCH) and a specific RS may also be referred to as a TCI state for the PDSCH, etc.

[0120] The UE may also be notified (set) of M (M≥1) TCI states for PDSCH (QCL information for M PDSCHs) through high-layer signaling. In addition, the number M of TCI states set for the UE may also be limited by at least one of the UE capability and the QCL type.

[0121] The DCI for scheduling PDSCH may also include a specific field indicating the TCI state for the PDSCH (e.g., may also be referred to as a TCI field, a TCI state field, etc.). The DCI may also be used for scheduling PDSCH of a cell, for example, may also be referred to as DL DCI, DL allocation, DCI format 1_0, DCI format 1_1, etc.

[0122] Whether the TCI field is included in the DCI can also be controlled by information notified from the base station to the UE. The information can also be information indicating whether the TCI field exists (present or absent) in the DCI (for example, TCI existence information, TCI existence information in DCI, and high-level parameter TCI-PresentInDCI). The information can also be set to the UE through, for example, high-level signaling.

[0123] In the case where more than 8 TCI states are set for the UE, MAC CE can also be used to activate (or specify) less than 8 TCI states. The MAC CE can also be called UE-specific PDSCH TCI state activation / deactivation MAC CE (TCIStates Activation / Deactivation for UE-specific PDSCH MAC CE). The value of the TCI field in the DCI can also represent one of the TCI states activated by the MAC CE.

[0124] When the UE sets TCI existence information set to "valid (enabled)" for the CORESET that schedules PDSCH (CORESET used to send PDCCH that schedules PDSCH), the UE can also assume that the TCI field exists in the DCI format 1_1 of the PDCCH sent on the CORESET.

[0125] When TCI existence information is not set for the CORESET that schedules the PDSCH, or the PDSCH is scheduled by DCI format 1_0, when the time offset between the reception of the DL DCI (DCI that schedules the PDSCH) and the reception of the PDSCH corresponding to the DCI is greater than a threshold, in order to determine the QCL of the PDSCH antenna port, the UE may also assume that the TCI state or QCL assumption for the PDSCH is the same as the TCI state or QCL assumption applied to the CORESET sent by the PDCCH used to schedule the PDSCH.

[0126] For example, the UE may also use a set of specific RSs (e.g., 64) corresponding to the TCI state set by high-level signaling as new candidate beam RSs. In this case, the UE may also select a specific RS (e.g., the RS with the highest RSRP) that meets specific conditions from the specific RS set, and report information related to the specific RS (e.g., RS index) to the base station.

[0127] Alternatively, the UE may use a set of RSs (eg, 8) activated by the MAC CE from among a set of RSs configured by higher-layer signaling as new candidate beam RSs.

[0128] In this way, even when the BFR process is set but the RS for the new candidate beam is not set, the UE can report information related to the new candidate beam to the base station using a set of specific RSs.

[0129] <Scenario 5>

[0130] A set of specific RSs set in a specific cell (or a specific CC) or a set of specific RSs set in other cells may also be applied as new candidate beam RSs. For example, when a BFR process (e.g., BFD RS) of a specific cell is set but a new candidate beam RS is not set, the UE may recognize that the new candidate beam RS is a set of specific RSs set in the cell (or other cells).

[0131] The specific RS may also be a synchronization signal block (e.g., SSB, or SS / PBCH). The other cell may also be a cell (or CC) belonging to the same band as the specific cell. Information related to the SSB set in each cell may also be notified to the UE from the base station through at least one of the higher layer signaling and the MAC control signal.

[0132] Therefore, even when the BFR process is set but the RS for the new candidate beam is not set, the UE can report information related to the new candidate beam to the base station using a set of specific RSs.

[0133] In addition, when a specific cell and other cells have a specific QCL relationship (for example, a type D-QCL relationship), the UE may also be configured to use a specific RS of other cells as a new candidate beam RS. Thus, when a beam failure occurs in a specific cell, a new candidate beam can be selected based on the new candidate beam RS of other cells having a specific QCL relationship, so that a new candidate beam can be appropriately selected.

[0134] (Second method)

[0135] In the second embodiment, a specific example of setting or selecting a new candidate beam RS in the BFR process of a specific cell (eg, SCell) is described. In addition, in the following description, at least one of the situations 1-5 described in the first embodiment can also be combined and applied.

[0136] <Method 1>

[0137] Figure 3 This shows an example in which a new candidate beam RS is not set in one CC (here CC#m) and a new candidate beam RS is set in another CC (here CC#n) among CC#m (or cell#m) and CC#n (or cell#n). In addition, CC#m and CC#n may also be CCs belonging to the same frequency band. Alternatively, CC#m and CC#n may also be CCs to which intra-band CA (Intra-band CA) is applied.

[0138] When the UE detects a beam failure in CC#m, it reports the detection of the beam failure and reports information related to the new candidate beam to the base station. In addition, the detection of the beam failure and the reporting of the information related to the new candidate beam can be performed at different timings or at the same timing. The reporting of the beam failure or the reporting of the information related to the new candidate beam can be performed using CC#m or other CCs (for example, CC#n).

[0139] The information related to the new candidate beam may also be information indicating a specific RS index or beam index. Alternatively, the information related to the new candidate beam may also be information indicating that the new candidate beam does not exist (for example, a beam or RS that satisfies a specific condition (for example, RSRP is above a specific value) does not exist).

[0140] When beam failure is detected, the UE determines a specific new candidate beam RS (e.g., index) to be reported based on the new candidate beam RS. When a new candidate beam RS is set in a CC (e.g., CC#m) in which beam failure is detected by higher layer signaling, etc., a specific RS index is determined based on the measurement result of the set new candidate beam RS (e.g., at least one of RSRP, RSSI, RSRQ, and SINR).

[0141] When the new candidate beam RS is not set (or does not exist) in CC#m, the UE may also use the new candidate beam RS set in other CCs (e.g., CC#n). That is, the UE may also determine that the set of new candidate beam RSs in CC#m is the set of new candidate beam RSs set in CC#n. Thus, even when the new candidate beam RS is not set in CC#m, information related to the new candidate beam can be reported for the beam failure generated in CC#m.

[0142] In addition, when a new candidate beam RS is set in multiple CCs other than CC#m, the UE may also apply a new candidate beam RS set in a specific CC among the multiple CCs as a new candidate beam RS in CC#m. The specific CC may be determined based on a CC index (or cell index), may be determined based on information notified from a base station, or may be determined based on the type of CC (or cell).

[0143] For example, the UE may also determine the new candidate beam RS set in the CC with the smallest (or largest) CC index as the new candidate beam RS in CC#m. Alternatively, the UE may also determine the new candidate beam RS set in a specific type of CC (e.g., PCell or PSCell) as the new candidate beam RS in CC#m. Alternatively, the base station may notify the UE of the CC used as the new candidate beam RS for CC#m.

[0144] Alternatively, when the specific RS configured in CC#m and the new candidate beam RS configured in CC#n have a specific QCL relationship, the UE may use the specific RS configured in CC#m as the new candidate beam RS.

[0145] <Method 2>

[0146] Figure 4 This shows an example in which the RS for the new candidate beam is not set in at least one CC (here CC#n) of CC#m (or cell #m) and CC#n (or cell #n). In addition, this shows a case in which a specific RS (or RS set) is set in CC#m and CC#n. The specific RS set set in CC#m can be a new candidate beam RS or another RS ​​set.

[0147] Here, it is assumed that the TCI state of the PDCCH of CC#m is set to be QCL ({QCL-A: TRS of CC#m, QCL-D: TRS of CC#m}) corresponding to the reference signal (TRS) of CC#m.

[0148] In addition, consider the case where the TCI state of the PDCCH of CC#n is set to be QCL ({QCL-A: TRS of CC#n, QCL-D: TRS of CC#n}) with respect to the reference signal (TRS) of CC#n (Case A), and the case where a part (for example, QCL-D) is set to be QCL ({QCL-A: TRS of CC#n, QCL-D: TRS of CC#m}) with respect to the reference signal (TRS) of CC#m (Case B).

[0149] When the UE detects beam failure in CC#n (or BFD RS is set in CC#n), it reports the detection of the beam failure and reports information related to the new candidate beam to the base station.

[0150] On the other hand, it is assumed that a new candidate beam RS is not configured (or does not exist) in CC#n. In such a case, the UE may apply at least one of the following options A and B.

[0151] [Option A]

[0152] When a specific RS (or a specific RS set) is set in CC#n, the UE may also use the specific RS as a new candidate beam RS in CC#n. The specific RS is not a new candidate beam RS, but is equivalent to an RS set in the UE. In other words, the UE may also determine the specific RS set set in CC#n as a set of new candidate beam RSs in CC#n.

[0153] In this case, the UE can decide a new candidate beam to be reported based on a specific RS set in CC#n where beam failure is detected.

[0154] [Option B]

[0155] Alternatively, when a specific RS (or a specific RS set) is set in another CC (e.g., CC#m), the specific RS is used as the new candidate beam RS in CC#n. In other words, the UE may also determine that the set of new candidate beam RSs in CC#n is the specific RS set set in CC#m.

[0156] CC#m and CC#n may also be CCs belonging to the same frequency band. Alternatively, CC#m and CC#n may also be CCs to which intra-band CA is applied. In this case, the UE can determine the new candidate beam to be reported based on a specific RS set in a CC different from CC#n where beam failure is detected (e.g., CC#n).

[0157] In addition, a specific RS set in CC#n and a specific RS set in another CC (e.g., CC#m) (e.g., a new candidate beam RS or an RS for other purposes) may also have a specific QCL relationship (e.g., case B). For example, option B may also be limited to a case where CC#n and another CC (e.g., CC#m) have a specific QCL relationship (e.g., case B). In this case, the UE may also control not to apply option B to case A.

[0158] Furthermore, the UE may switch between option A and option B and apply them according to scenario A and scenario B. Alternatively, a configuration may be adopted in which one of option A and option B is applied regardless of the scenario. At least one of the scenario and option to be applied may be set to the UE from the base station.

[0159] <Method 3>

[0160] Figure 5This shows an example in which a plurality of CCs (e.g., CC#m, CC#n, CC#p) are grouped and a new candidate beam RS is set in at least one CC included in the group. Here, this shows a case in which a new candidate beam RS is set in CC#m but not in CC#n and CC#p. In addition, the number of CCs in which a new candidate beam RS is set is not limited to one.

[0161] It is also possible to assume that a plurality of CC groups are configured for the UE, and that a new candidate beam RS is configured in at least one CC included in the CC group. Information on the CC group may also be configured from the base station to the UE using higher layer signaling or the like.

[0162] Alternatively, the UE may assume that all configured SCells are included in the same group. Alternatively, the UE may assume that SCells included in a specific range (for example, the same frequency band or secondary cell group) are included in the same group.

[0163] In addition, the base station may also notify the UE of information related to the CC in which the new candidate beam RS is set in the group through high-layer signaling, etc. Alternatively, the base station may also notify the UE of information related to a specific RS applied as a new candidate beam RS in each CC included in the group (for example, an RS index, or information related to the CC in which the specific RS is set, etc.) through high-layer signaling, etc.

[0164] When the new candidate beam RS is not configured in CC#n where beam failure occurs (or BFD RS is configured), the UE may use the new candidate beam RS configured in other CCs (e.g., CC#m). That is, the UE may determine that the set of new candidate beam RSs in CC#n is the set of new candidate beam RSs configured in other CC#m included in the same CC group #1.

[0165] Alternatively, the UE may determine that the set of new candidate beam RSs in CC#n is a specific RS set configured in the CC#n or a specific RS set configured in another CC#m included in the same CC group #1.

[0166] In this way, by using new candidate beam RSs or a specific RS set of other CCs included in the same CC group as new candidate beam RSs of a specific CC, it is not necessary to set new candidate beam RSs in each CC. This can improve resource utilization efficiency.

[0167] (Wireless Communication System)

[0168] 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 one of the wireless communication methods according to the above-mentioned embodiments of the present disclosure or a combination thereof.

[0169] Figure 6 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.

[0170] In addition, the wireless communication system 1 can also support dual connectivity between multiple radio access technologies (Radio Access Technology) (RAT) (Multi-RAT Dual Connectivity (MR-DC)). MR-DC can also include dual connectivity between LTE (Evolved Universal Terrestrial Radio Access (E-UTRA))) and NR (E-UTRA-NR Dual Connectivity (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.

[0171] 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.

[0172] 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)).

[0173] The wireless communication system 1 may also include: a base station 11 that forms a macro cell C1 with a relatively wide coverage, and a base station 12 (12a-12c) that is configured 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 configuration and number of each cell and the user terminal 20 are not limited to the method shown in the figure. Hereinafter, when the base stations 11 and 12 are not distinguished, they are collectively referred to as the base station 10.

[0174] 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).

[0175] 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 (lower than 6 GHz (sub-6 GHz)), and FR2 may be a frequency band higher than 24 GHz (higher than 24 GHz (above-24 GHz)). In addition, the frequency bands and definitions of FR1 and FR2 are not limited to this. For example, FR1 may also correspond to a frequency band higher than FR2.

[0176] Furthermore, the user terminal 20 may perform communication in each CC using at least one of time division duplex (TDD) and frequency division duplex (FDD).

[0177] Multiple base stations 10 may also be connected by wire (e.g., optical fiber based on Common Public Radio Interface (CPRI)), X2 interface, etc.) or wirelessly (e.g., NR communication). For example, when NR communication between base stations 11 and 12 is used as a backhaul, the base station 11 equivalent to the upper station may also be referred to as an Integrated Access Backhaul (IAB) donor, and the base station 12 equivalent to a relay station may also be referred to as an IAB node.

[0178] 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), a Next Generation Core (NGC), and the like.

[0179] The user terminal 20 may also be a terminal that supports at least one of communication modes such as LTE, LTE-A, and 5G.

[0180] 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 (UL), 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.

[0181] The radio access scheme may also be referred to as a waveform. In addition, in the wireless communication system 1, other radio access schemes (for example, other single-carrier transmission schemes, other multi-carrier transmission schemes) may be applied to the UL and DL radio access schemes.

[0182] In the wireless communication system 1, as downlink channels, 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)) and the like may be used.

[0183] 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.

[0184] The PDSCH is used to transmit user data, high-layer control information, system information block (SIB), etc. The PUSCH is also used to transmit user data, high-layer control information, etc. In addition, the PBCH is also used to transmit the master information block (MIB).

[0185] 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 of at least one of the PDSCH and the PUSCH.

[0186] In addition, the DCI for scheduling PDSCH may also be referred to as DL allocation, DL DCI, etc., and the DCI for scheduling PUSCH may also be referred to as UL grant, UL DCI, etc. In addition, PDSCH may also be replaced by DL data, and PUSCH may also be replaced by UL data.

[0187] 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. One CORESET can also be associated with one or more search spaces. The UE can also monitor the CORESET associated with a certain search space based on the search space setting.

[0188] 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 "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.

[0189] 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 PUCCH. Random access preamble code for establishing connection with a cell can also be transmitted through PRACH.

[0190] In the present disclosure, downlink, uplink, etc. may be expressed without "link". In addition, various channels may be expressed without "Physical" at the beginning.

[0191] 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.

[0192] The synchronization signal may 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 an SS / PBCH block, SS block (SS Block (SSB)), etc. In addition, SS, SSB, etc. may also be referred to as reference signals.

[0193] 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).

[0194] (Base Station)

[0195] Figure 7 1 is a diagram showing an example of a structure of a base station involved in one 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 path interface (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 path interface 140 may each be provided with more than one.

[0196] In addition, in this example, the functional blocks of the characteristic parts of this embodiment are mainly shown, and the base station 10 may also be assumed to have other functional blocks required for wireless communication. Part of the processing of each unit described below may be omitted.

[0197] 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 the common knowledge in the technical field to which the present disclosure relates.

[0198] The control unit 110 may also control signal generation, scheduling (e.g., resource allocation, mapping), etc. The control unit 110 may also control transmission and 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.

[0199] 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 (phase shifter), a measuring circuit, a transmitting and receiving circuit, etc., which are described based on the public knowledge in the technical field involved in the present disclosure.

[0200] 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.

[0201] The transmitting / receiving antenna 130 can be constituted by an antenna described based on the common knowledge in the technical field involved in the present disclosure, such as an array antenna.

[0202] 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.

[0203] 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 transmitting beam and a receiving beam.

[0204] The sending and receiving unit 120 (sending processing unit 1211), for example, 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 to generate a bit string to be sent.

[0205] 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, 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.

[0206] The transmitting and receiving unit 120 (RF unit 122 ) may 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 .

[0207] On the other hand, the transmitting and receiving unit 120 (RF unit 122 ) may perform amplification, filter processing, demodulation into a baseband signal, etc. on the signal in the radio frequency band received by the transmitting and receiving antenna 130 .

[0208] 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 to obtain user data, etc.

[0209] 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 also perform radio resource management (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 (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 results may also be output to the control unit 110.

[0210] The transmission path interface 140 can also send and receive signals (return signaling) between 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.

[0211] In addition, the transmission unit and the reception unit of the base station 10 in the present disclosure may also be constituted by at least one of the transmission and reception unit 120 , the transmission and reception antenna 130 , and the transmission path interface 140 .

[0212] In addition, when a beam failure of a specific cell is detected, the transceiver 120 receives information related to a new candidate beam (eg, RS index, etc.) In addition, the transceiver 120 may also transmit information related to the RS for the new candidate beam and information related to the specific RS.

[0213] The control unit 110 controls the setting of the new candidate beam RS for each cell (or CC). In addition, the control unit 110 may control so that in a cell where the new candidate beam RS is not set, other RSs are applied to the UE as new candidate beam RSs.

[0214] (User Terminal)

[0215] Figure 82 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 be provided in one or more pieces.

[0216] In addition, in this example, the functional blocks of the characteristic parts in this embodiment are mainly shown, and the user terminal 20 may also be assumed to have other functional blocks required for wireless communication. Part of the processing of each unit described below may be omitted.

[0217] 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 the common knowledge in the technical field to which the present disclosure relates.

[0218] The control unit 210 may also control signal generation, mapping, etc. The control unit 210 may also control transmission and 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.

[0219] 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 described based on the public knowledge in the technical field involved in the present disclosure.

[0220] 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.

[0221] The transmitting / receiving antenna 230 can be constituted by an antenna described based on the common knowledge in the technical field involved in the present disclosure, such as an array antenna.

[0222] 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.

[0223] 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.

[0224] 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.

[0225] 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.

[0226] In addition, whether to apply DFT processing may also be based on the setting of transform precoding. For a certain channel (e.g., PUSCH), when transform precoding is activated (enabled), the transmitting and receiving unit 220 (transmitting processing unit 2211) may also perform DFT processing as the above-mentioned transmission processing in order to transmit the channel using a DFT-s-OFDM waveform. Otherwise, the transmitting and receiving unit 220 (transmitting processing unit 2211) may also perform DFT processing as the above-mentioned transmission processing without performing DFT processing.

[0227] 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 .

[0228] On the other hand, the transmitting and receiving unit 220 (RF unit 222 ) may 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 .

[0229] The sending and receiving unit 220 (receiving processing unit 2212) can also apply 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.

[0230] 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 measurements, CSI measurements, 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 results may also be output to the control unit 210.

[0231] In addition, the transmitting unit and the receiving unit of the user terminal 20 in the present disclosure may also be constituted by at least one of the transmitting and receiving unit 220 and the transmitting and receiving antenna 230 .

[0232] In addition, when a beam failure of a specific cell is detected, the transmission and reception unit 220 transmits information related to a new candidate beam. In addition, the transmission and reception unit 220 may receive information related to a new candidate beam RS and information related to a specific RS.

[0233] The control unit 210 performs control so as to use a specific reference signal as a reference signal for the new candidate beam when the reference signal for the new candidate beam has not been set.

[0234] The specific reference signal may also be at least one of a reference signal set for beam failure detection, a reference signal associated with a specific control resource set, a set of reference signals set in the transmission setting indication state of a downlink channel, a set of reference signals activated for transmission setting indication information of a downlink channel, and a set of reference signals set in a specific cell or other cells.

[0235] The specific reference signal may be a reference signal for a new candidate beam set in another cell different from the specific cell.

[0236] The specific reference signal may also be at least one of a set of reference signals set in a transmission setting indication state of a downlink channel set in a specific cell or other cells, and a set of reference signals activated for transmission setting indication information of a downlink channel.

[0237] The specific reference signal may also be at least one of a reference signal for a new candidate beam set in at least one cell in the same cell group, a set of reference signals set in the transmission setting indication state of a downlink channel, and a set of reference signals activated for transmission setting indication information of a downlink channel.

[0238] (Hardware Structure)

[0239] 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 by a 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, 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.

[0240] 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, 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 one of them is as described above, and the implementation method is not particularly limited.

[0241] 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. Fig. 9 1001, memory 1002, storage 1003, communication device 1004, input device 1005, output device 1006, bus 1007, etc.

[0242] In addition, in the present disclosure, the terms such as device, circuit, equipment, section, unit, etc. are interchangeable. The hardware structure of the base station 10 and the user terminal 20 may be configured to include one or more of the devices shown in the figure, or may be configured to exclude some of the devices.

[0243] 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 may be performed by two or more processors simultaneously, sequentially, or in other ways. In addition, the processor 1001 may also be implemented by one or more chips.

[0244] The functions of the base station 10 and the user terminal 20 are realized, for example, 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.

[0245] 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, an arithmetic device, a register, etc. For example, at least a part of the above-mentioned control unit 110 (210), the sending and receiving unit 120 (220), etc. may also be implemented by the processor 1001.

[0246] In addition, the processor 1001 reads the program (program code), software module, data, etc. from at least one of the storage 1003 and the communication device 1004 to the memory 1002, and performs various processes based on them. As a program, a program that enables a computer to perform at least a part of the operations described in the above-mentioned 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 in the processor 1001, and the same can be implemented for other functional blocks.

[0247] The memory 1002 may also be a computer-readable recording medium, for example, composed of 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 appropriate 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 executable programs (program codes), software modules, etc. for implementing the wireless communication method involved in one embodiment of the present disclosure.

[0248] 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 (registered trademark) disk, a removable disk, a hard disk drive, a smart card, a flash memory device (such as 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.

[0249] 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. In order to realize at least one of frequency division duplex (Frequency Division Duplex (FDD)) and time division duplex (Time Division Duplex (TDD)), the communication device 1004 can also be configured to include a high-frequency switch, a duplexer, a filter, a frequency synthesizer, etc. For example, the above-mentioned transmitting and receiving unit 120 (220), the transmitting and receiving antenna 130 (230), etc. can also be realized by the communication device 1004. The transmitting and receiving unit 120 (220) can also be installed by the transmitting unit 120a (220a) and the receiving unit 120b (220b) separately physically or logically.

[0250] 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).

[0251] In addition, the processor 1001, the 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 different buses may be used between the devices.

[0252] In addition, 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), a field programmable gate array (FPGA), etc., and the hardware may be used to implement a part or all of each functional block. For example, the processor 1001 may also be installed using at least one of these hardware.

[0253] (Variation Example)

[0254] In addition, the terms described in the present disclosure and the terms required for understanding the present disclosure may also be replaced with terms having the same or similar meanings. For example, channels, code elements, and signals (signals or signaling) may also be replaced with each other. In addition, a signal may also be a message. A reference signal may also be referred to as RS, and may also be referred to as a pilot, a pilot signal, etc. depending on the standard applied. In addition, a component carrier (CC) may also be referred to as a cell, a frequency carrier, a carrier frequency, etc.

[0255] A wireless frame may also be composed of one or more periods (frames) in the time domain. Each period (frame) of 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 also be a fixed time length (e.g., 1 ms) that is not dependent on a parameter set (numerology).

[0256] Here, the parameter set may also refer to a communication parameter applied in at least one of the transmission and reception of a certain signal or channel. For example, the parameter set may also represent at least one of the subcarrier spacing (SCS), bandwidth, symbol length, cyclic prefix length, transmission time interval (TTI), the number of symbols per TTI, wireless 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, etc.

[0257] 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.

[0258] A time slot may also include multiple mini-slots. Each mini-slot may also 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 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 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.

[0259] 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 their respective names. In addition, time units such as frames, subframes, time slots, mini-time slots, and symbols in the present disclosure may also be interchangeable.

[0260] For example, a subframe may also be referred to as a TTI, a plurality of consecutive subframes may also be referred to as a TTI, and a time slot or a mini time slot may also 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 also be referred to as a time slot, a mini time slot, etc. instead of a subframe.

[0261] 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 TTI units. In addition, the definition of TTI is not limited to this.

[0262] TTI may also be a transmission time unit for a data packet (transport block), a code block, a code word, etc. that has been channel-coded, and may 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 a transport block, a code block, a code word, etc. is actually mapped may also be shorter than the TTI.

[0263] In addition, when one time slot or one mini time slot is referred to as TTI, one or more TTIs (i.e., one or more time slots or one or more mini time slots) may also be the minimum time unit of scheduling. In addition, the number of time slots (mini time slots) constituting the minimum time unit of scheduling may also be controlled.

[0264] 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 time slot, a sub time slot, a time slot, etc.

[0265] In addition, a long TTI (e.g., normal TTI, subframe, etc.) may be replaced by a TTI having a time length exceeding 1 ms, and a short TTI (e.g., shortened TTI, etc.) may be replaced by a TTI having a TTI length shorter than that of the long TTI and longer than 1 ms.

[0266] A resource block (RB) is a resource allocation unit in the time domain and the frequency domain, and may also include one or more consecutive subcarriers (subcarriers) in the frequency domain. The number of subcarriers included in an RB may also be the same regardless of the parameter set, for example, 12. The number of subcarriers included in an RB may also be determined based on the parameter set.

[0267] 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, respectively.

[0268] 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.

[0269] In addition, a resource block may also be composed of one or more resource elements (RE). For example, one RE may also be a radio resource region of one subcarrier and one symbol.

[0270] 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 relative to a common reference point of the carrier. PRBs may also be defined in a BWP and numbered within the BWP.

[0271] 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.

[0272] At least one of the configured BWPs may be activated, and the UE may not assume that it transmits or receives a specific signal / channel other than the activated BWP. In addition, "cell", "carrier", etc. in the present disclosure may also be replaced by "BWP".

[0273] In addition, the above-mentioned structures such as radio frames, subframes, time slots, mini-time slots and symbols are only examples. For example, the number of subframes included in a radio frame, the number of time slots in each subframe or radio frame, the number of mini-time slots included in a time slot, the number of symbols and RBs included in a time slot or mini-time slot, the number of subcarriers included in an RB, the number of symbols in a TTI, the symbol length, and the cyclic prefix (CP) length can be changed in various ways.

[0274] 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.

[0275] In the present disclosure, the names used for parameters, etc. are not limiting in all respects. In addition, the mathematical formulas, etc. using these parameters may also be different from those explicitly disclosed in the present disclosure. The 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 limiting in all respects.

[0276] Information, signals, etc. described in the present disclosure may also be represented using any of a variety of different techniques. For example, data, instructions, commands, information, signals, bits, symbols, chips, etc. that may be 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.

[0277] Furthermore, information, signals, etc. can be output from a high layer (upper layer) to a low layer (lower layer) or from a low layer to a high layer. Information, signals, etc. can also be input and output via a plurality of network nodes.

[0278] The input and output information, signals, etc. may be stored in a specific location (e.g., a memory), or may be managed using a management table. The input and output information, signals, etc. may be overwritten, updated, or appended. The output information, signals, etc. may also be deleted. The input information, signals, etc. may also be sent to other devices.

[0279] 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.

[0280] 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, such as an RRC connection establishment (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 (MACControl Element (CE)).

[0281] 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).

[0282] The determination can be made by a value represented by a bit (0 or 1), by a true or false value (Boolean value) represented by true or false, or by comparison of numerical values ​​(for example, comparison with a specific value).

[0283] Whether software is called software, firmware, middle-ware, microcode, hardware description language, or other names, it should be broadly interpreted as meaning instructions, instruction sets, code, code segments, program code, program, sub-program, software modules, applications, software applications, software packages, routines, sub-routines, objects, executable files, execution threads, procedures, functions, etc.

[0284] In addition, software, instructions, information, etc. may also be sent and received via a transmission medium. For example, when software is sent from a website, server, or other remote source using at least one of wired technology (coaxial cable, fiber optic cable, twisted pair, 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.

[0285] The terms "system" and "network" used in the present disclosure can be used interchangeably. "Network" may also refer to a device (eg, a base station) included in the network.

[0286] 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.

[0287] In the present 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" can be used interchangeably. There are also cases where base stations are referred to by terms such as macro cell, small cell, micro cell, and pico cell.

[0288] 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 the entirety of the coverage area of ​​at least one of a base station and a base station subsystem that provides communication services within the coverage area.

[0289] In the present disclosure, terms such as “Mobile Station (MS)”, “user terminal”, “User Equipment (UE)”, and “terminal” can be used interchangeably.

[0290] In some cases, the mobile station is also 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 hand set, a user agent, a mobile client, a client, or some other appropriate terminology.

[0291] 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 carried in a mobile body, a mobile body, etc. The mobile body may be a means of transportation (e.g., a vehicle, an airplane, etc.), a mobile body that moves in an unmanned manner (e.g., a drone, an autonomous driving 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 when performing a communication operation. 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.

[0292] 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, it may also be referred to as device-to-device (D2D)), vehicle-to-everything (V2X), etc.). In this case, it may also be set as a structure in which the user terminal 20 has the functions possessed by the above-mentioned base station 10. In addition, expressions such as "uplink" and "downlink" may also be replaced by expressions 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.

[0293] 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.

[0294] In the present disclosure, operations are set to be performed by a base station, and sometimes by its upper node depending on the situation. Obviously, in a network including one or more network nodes having a base station, various operations performed for communication with a terminal can be performed by a base station, one or more network nodes other than the base station (for example, considering a Mobility Management Entity (MME)), a Serving-Gateway (S-GW), etc., but not limited to these), or a combination thereof.

[0295] The various methods / implementations described in this disclosure may be used individually or in combination, and may be used in a switched manner as the method is executed. In addition, the processing procedures, sequences, flow charts, etc. of the various methods / implementations described in this disclosure may be reversed in order as long as they are not contradictory. For example, for the methods described in this disclosure, the elements of various steps are presented in an illustrative order, but are not limited to the specific order presented.

[0296] The various modes and implementation modes 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), 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 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 example, LTE or LTE-A, combination with 5G, etc.) for application.

[0297] The term “based on” used in the present disclosure does not mean “based only on” unless otherwise specified. In other words, the term “based on” means both “based only on” and “based at least on”.

[0298] Any reference to an element using the terms "first", "second", etc. used in this disclosure does not fully define the amount or order of these elements. These terms can be used in this disclosure as a convenient method to distinguish between two or more elements. Therefore, reference to a first and a second element does not mean that only two elements can be used, or that the first element must take precedence over the second element in some form.

[0299] The term "determining" as used in this disclosure may include a variety of operations in some cases. For example, "determining" may also be viewed as "judging", calculating, computing, processing, deriving, investigating, looking up (e.g., searching in a table, database, or other data structure), ascertaining, etc.

[0300] In addition, "judgment (decision)" can also be regarded as a situation of "judgment (decision)" on receiving (for example, receiving information), transmitting (for example, sending information), input (input), output (output), accessing (for example, accessing data in a memory), etc.

[0301] In addition, "judgment (decision)" can also be regarded as a situation of "judgment (decision)" on resolving, selecting, choosing, establishing, comparing, etc. In other words, "judgment (decision)" can also be regarded as a situation of "judgment (decision)" on some operations.

[0302] In addition, "judge (decide)" can also be replaced by "assuming (assuming)", "expecting (expecting)", "considering (considering)" and so on.

[0303] The terms "connected", "coupled", or all their variations used in this disclosure mean all direct or indirect connections or combinations between two or more elements, and may include the situation where one or more intermediate elements exist between two elements that are "connected" or "coupled" to each other. The combination or connection between elements may be physical, logical, or a combination of these. For example, "connection" may also be replaced by "access".

[0304] 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., 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.

[0305] 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 "combined" may also be interpreted as "different".

[0306] In the present disclosure, when the terms "include", "including", and their variations are used, these terms, like the term "comprising", have an inclusive meaning. Furthermore, the term "or" used in the present disclosure does not mean an exclusive OR.

[0307] In the present disclosure, when an article is added by translation like a, an, and the in English, for example, the present disclosure may also include a case where the noun following the article is in plural form.

[0308] The invention involved in the present disclosure has been described in detail above, but it is obvious to those skilled in the art that the invention involved in the present disclosure is not limited to the embodiments described in the present disclosure. The invention involved in the present disclosure can be implemented as a modified and altered mode without departing from the gist and scope of the present invention determined based on the description of the claims. Therefore, the description of the present disclosure is for the purpose of illustrative description and does not have any limiting meaning on the invention involved in the present disclosure.

Claims

1. A terminal having: a receiving unit that receives, through high-layer signaling, information about a cell in which a candidate beam reference signal is set and information about an index of the candidate beam reference signal when a cell group including a plurality of cells is set; and a control unit for controlling, when a beam failure is detected, information indicating that a candidate beam reference signal having a reception power exceeding a specific value does not exist is sent and a recovery request is sent via the PUCCH, The candidate beam reference signal corresponding to each cell is always set in a specific frequency domain.

2. A wireless communication method of a terminal, comprising: When a cell group including a plurality of cells is set, receiving, through higher layer signaling, information of a cell in which a candidate beam reference signal is set and information of an index of the candidate beam reference signal; and A step of controlling, when a beam failure is detected, to send information indicating that a candidate beam reference signal having a reception power greater than a specific value does not exist and to send a recovery request via PUCCH, The candidate beam reference signal corresponding to each cell is always set in a specific frequency domain.

3. A base station, comprising: a transmitting unit, which transmits information of a cell in which a candidate beam reference signal is set and information of an index of the candidate beam reference signal to a terminal through high-layer signaling when a cell group including a plurality of cells is set; and a control unit that, when a beam failure is detected in the terminal, receives information indicating that a candidate beam reference signal having a reception power exceeding a specific value does not exist, and controls reception of a recovery request transmitted via a PUCCH, The candidate beam reference signal corresponding to each cell is always set in a specific frequency domain.

4. A system having a terminal and a base station, wherein: The terminal has: a receiving unit, which receives, through high-layer signaling, information of a cell in which a candidate beam reference signal is set and information of an index of the candidate beam reference signal when a cell group including a plurality of cells is set; as well as a control unit for controlling, when a beam failure is detected, information indicating that a candidate beam reference signal having a reception power exceeding a specific value does not exist is sent and a recovery request is sent via the PUCCH, The candidate beam reference signal corresponding to each cell is always set in a specific frequency domain. The base station has: a sending unit, configured to send information of a cell in which the candidate beam reference signal is set and information of an index of the candidate beam reference signal to the terminal through the high-layer signaling; as well as The control unit controls reception of information indicating that a candidate beam reference signal having a reception power exceeding a specific value does not exist and a recovery request.

Images