Terminal and beam failure recovery method

Abstract

This technology provides a wireless communication system that enables terminals to properly detect and recover from high-frequency communication failures. [Solution] The terminal includes a receiving unit that monitors the quality of the beam, and a control unit that initiates a beam failure recovery procedure when a predetermined condition is met in the number of times the quality degradation of all beams in a given set has been detected after the timer has started but before the timer has expired.

Description

Technical Field

[0001] The present invention relates to a terminal and a base station device in a wireless communication system.

Background Art

[0002] In NR (New Radio), which is a successor system to LTE (Long Term Evolution) (also referred to as "5G"), technologies that meet requirements such as a large-capacity system, high data transmission speed, low latency, simultaneous connection of a large number of terminals, low cost, and power saving are being studied (for example, Non-Patent Document 1). In addition, in NR, the use of high-frequency bands such as 52.6 to 114.25 GHz is being studied.

[0003] In addition, in the NR system, in order to expand the frequency band, the use of a frequency band licensed to a communications carrier (operator) (a frequency band different from the licensed band (unlicensed band, unlicensed carrier, unlicensed CC)) is supported.

Prior Art Documents

Non-Patent Documents

[0004]

Non-Patent Document 1

Non-Patent Document 2

Non-Patent Document 3

Non-Patent Document 4

Summary of the Invention

[0005] In NR, various functions for detecting and recovering from wireless link failures are specified (e.g., Non-Patent Documents 2-4). In addition, various functions for detecting and recovering from beam failures are also specified in NR (e.g., Non-Patent Documents 2-4).

[0006] However, terminals that conform to existing NR regulations, which are designed for frequency bands up to 52.6 GHz, may not be able to properly perform wireless link / beam fault detection and recovery in high-frequency bands such as 52.6 to 114.25 GHz.

[0007] The present invention has been made in view of the above points, and aims to provide a technology that enables a terminal in a wireless communication system to appropriately detect and recover from high-frequency communication failures. [Means for solving the problem]

[0008] According to the disclosed technology, a receiver monitors the quality of the beam, A control unit that initiates a beam failure recovery procedure if the number of times quality degradation of all beams in a given set is detected after the timer is started but before the timer expires exceeds a threshold, A terminal equipped with this feature is provided. [Effects of the Invention]

[0009] According to the disclosed technology, a technology is provided that enables a terminal in a wireless communication system to properly detect and recover from high-frequency communication failures. [Brief explanation of the drawing]

[0010] [Figure 1] This figure illustrates a wireless communication system in an embodiment of the present invention. [Figure 2] This figure illustrates a wireless communication system in an embodiment of the present invention. [Figure 3] This is a diagram showing an example of a band. [Figure 4] This is a diagram showing the relationship between SCS and symbol length. [Figure 5] This is a diagram showing an example of the basic procedure in an embodiment of the present invention. [Figure 6] This is a diagram showing an example of the RLM / RLF procedure. [Figure 7] This is a diagram for explaining a new timer. [Figure 8] This is a diagram for explaining Rel-15 BFR. [Figure 9] This is a diagram for explaining Rel-16 BFR. [Figure 10] This is a diagram for explaining the transmission status of CSI-RS / SSB when performing LBT. [Figure 11] This is a diagram for explaining the timing of PDCCH monitoring during BFR. [Figure 12] This is a diagram for explaining the timing of QCL update. [Figure 13] This is a diagram for explaining Multi-CC BFR. [Figure 14] This is a diagram showing an example of a MAC CE for beam reporting. [Figure 15] This is a diagram showing an example of a PRACH sequence for beam reporting. [Figure 16] This is a diagram showing the 2-step RACH procedure. [Figure 17] This is a diagram showing an example of the functional configuration of the base station device 10 in an embodiment of the present invention. [Figure 18] This is a diagram showing an example of the functional configuration of the terminal 20 in an embodiment of the present invention. [Figure 19] This is a diagram showing an example of the hardware configuration of the base station device 10 or the terminal 20 in an embodiment of the present invention.

Embodiments for Carrying Out the Invention

[0011] Embodiments of the present invention will be described below with reference to the drawings. Note that the embodiments described below are examples, and the embodiments to which the present invention is applied are not limited to those described below.

[0012] In the operation of the wireless communication system according to the embodiment of the present invention, existing technologies are used as appropriate. Such existing technologies include, for example, existing NR (New Radio) technologies. The wireless communication system in this embodiment (base station device 10 and terminal 20) basically operates in accordance with existing regulations (e.g., Non-Patent Documents 1-4 and the R-16 specification). However, in order to solve the problems that arise when considering the use of high-frequency bands, the base station device 10 and terminal 20 also perform operations that are not included in the existing regulations. The description of the embodiments described later mainly describes operations that are not included in the existing regulations. Note that the numerical values ​​described below are all examples.

[0013] Furthermore, in the embodiments of the present invention, the duplex method may be a TDD (Time Division Duplex) method, an FDD (Frequency Division Duplex) method, or any other method (for example, a Flexible Duplex).

[0014] Furthermore, in the embodiments of the present invention, "configuring" wireless parameters may mean that predetermined values ​​are pre-configured, or that wireless parameters notified from the base station device 10 or terminal 20 are configured.

[0015] (System Configuration)

[0016] Figure 1 is a diagram illustrating a wireless communication system in an embodiment of the present invention. The wireless communication system in the embodiment of the present invention includes a base station device 10 and a terminal 20, as shown in Figure 1. Figure 1 shows one base station device 10 and one terminal 20, but this is an example, and there may be multiple of each.

[0017] The base station device 10 is a communication device that provides one or more cells and performs wireless communication with the terminal 20. The physical resources of the wireless signal are defined in the time domain and the frequency domain.

[0018] OFDM is used as the wireless access method. In the frequency domain, subcarrier spacing (SCS) of at least 15kHz, 30kHz, 120kHz, and 240kHz are supported. In addition, regardless of the SCS, a resource block is composed of a predetermined number (e.g., 12) consecutive subcarriers.

[0019] When terminal 20 performs initial access, it detects the SSB (SS / PBCH block) and identifies the SCS in the PDCCH and PDSCH based on the PBCH contained in the SSB.

[0020] Furthermore, in the time domain, a slot is composed of multiple OFDM symbols (for example, 14 symbols regardless of the subcarrier interval). Hereafter, OFDM symbols will be referred to as "symbols." A slot is a scheduling unit. In addition, a subframe of 1ms interval is defined, and a frame consisting of 10 subframes is defined. Note that the number of symbols per slot is not limited to 14.

[0021] As shown in Figure 1, the base station device 10 transmits control information or data to the terminal 20 via DL (Downlink) and receives control information or data from the terminal 20 via UL (Uplink). Both the base station device 10 and the terminal 20 are capable of transmitting and receiving signals using beamforming. Furthermore, both the base station device 10 and the terminal 20 are capable of applying MIMO (Multiple Input Multiple Output) communication to DL or UL. In addition, both the base station device 10 and the terminal 20 may communicate via SCell (Secondary Cell) and PCell (Primary Cell) using CA (Carrier Aggregation).

[0022] Terminal 20 is a communication device equipped with wireless communication capabilities, such as a smartphone, mobile phone, tablet, wearable device, or M2M (Machine-to-Machine) communication module. As shown in Figure 1, Terminal 20 receives control information or data from the base station device 10 via DL and transmits control information or data to the base station device 10 via UL, thereby utilizing various communication services provided by the wireless communication system.

[0023] Terminal 20 is capable of carrier aggregation, which involves bundling multiple cells (multiple CCs (component carriers)) to communicate with base station equipment 10. Carrier aggregation uses one PCell (primary cell) and one or more SCells (secondary cells). A PUCCH-SCell with a PUCCH may also be used.

[0024] Figure 2 shows an example of a wireless communication system configuration when NR-DC (NR-Dual connectivity) is implemented. As shown in Figure 2, the system is equipped with a base station device 10A which acts as the MN (Master Node) and a base station device 10B which acts as the SN (Secondary Node). Base station devices 10A and 10B are each connected to the core network. Terminal 20 communicates with both base station devices 10A and 10B.

[0025] A cell group provided by base station equipment 10A, which is an MN, is called an MCG (Master Cell Group), and a cell group provided by base station equipment 10B, which is an SN, is called an SCG (Secondary Cell Group). In a DC, an MCG consists of one PCell and one or more SCells, and an SCG consists of one PSCell (Primary SCell) and one or more SCells. In this specification, CC (Component Carrier) and cell may be used synonymously. Also, PCell and PSCell may be called SPCells.

[0026] In the wireless communication system of this embodiment, when using an unlicensed band, LBT (Listen Before Talk) is performed. The base station device 10 or terminal 20 transmits if the LBT result is idle, and does not transmit if the LBT result is busy.

[0027] (Regarding frequency bands) Figure 3 shows examples of frequency bands used in existing NR and frequency bands used in the wireless communication system according to this embodiment. There are two frequency bands (which may also be called frequency ranges) in existing NR: FR1 (0.41 GHz to 7.125 GHz) and FR2 (24.25 GHz to 52.6 GHz). As shown in Figure 3, FR1 supports 15 kHz, 30 kHz, and 60 kHz as SCS frequencies and a bandwidth (BW) of 5 to 100 MHz. FR2 supports 60 kHz, 120 kHz, and 240 kHz (SSB only) as SCS frequencies and a bandwidth (BW) of 50 to 400 MHz.

[0028] The wireless communication system according to this embodiment is intended to utilize a frequency band higher than 52.6 GHz (for example, 52.6 GHz to 114.25 GHz) that is not used in existing NR systems. This frequency band may also be referred to as FR4.

[0029] Furthermore, in this embodiment, as the frequency band is expanded as described above, it is assumed that a wider SCS than existing SCSs will be used. For example, a 480kHz or wider SCS will be used as the SCS for SSB and PDCCH / PDSCH.

[0030] (Regarding the issues) In the high-frequency band, it is anticipated that multiple narrow beams will be used to compensate for the large propagation losses. In addition, wider SCSs (e.g., 480 kHz, 960 kHz) will be used than the existing FR2 SCSs.

[0031] Figure 4 shows the relationship between SCS and symbol length (symbol duration). As shown in Figure 4, as the SCS widens, the symbol length (symbol duration) decreases. Also, assuming that the number of symbols per slot remains constant (i.e., 14 symbols), as the SCS widens, the slot length decreases.

[0032] Thus, when the beams become narrow and numerous, and the SCS becomes wide, if the terminal 20 and base station equipment 10 operate according to conventional specifications, there is a possibility that fault detection and recovery of the wireless link / beam may not be performed properly.

[0033] The following describes technologies that address the above-mentioned issues and enable the terminal 20 and base station equipment 10 to properly detect and recover from wireless link / beam failures in the high-frequency band.

[0034] (Basic operation) First, a basic example of operation in the wireless communication system of this embodiment will be explained with reference to Figure 5.

[0035] In S101, terminal 20 receives configuration information from base station device 10 via RRC message. This configuration information includes, for example, timers and thresholds used for RLM / RLF or BFD / BFR, as described later.

[0036] In S102, terminal 20 uses the configuration information received in S101 to perform processing related to RLM / RLF, BFD / BFR, etc. Note that processing may also be performed without using the configuration information.

[0037] Examples 1 to 8 of the wireless communication system of this embodiment will be described below as specific examples of processing operations. In Examples 1 to 8, any combination of multiple embodiments can be implemented as long as no inconsistencies arise.

[0038] (Example 1) <Example of basic operation in Example 1> In the wireless communication system of Example 1, the terminal 20 (and base station device 10) performs RLM (Radio Link Monitoring), and when it detects RLF (Radio Link Failure), it performs RRC connection re-establishment, etc.

[0039] In RLM, counter values ​​N310 and N311, which are threshold values ​​for the number of counts, and timers T310 and T311 are used. These parameters are received by terminal 20 from base station equipment 20 via RRC signaling.

[0040] N310 is the threshold for the number of consecutive out-of-sync indications. When the number of consecutive out-of-sync indications reaches N310, the timer T310 is started.

[0041] T310 is started by the trigger described above and stops after N311 consecutive in-sync indications are received. When T310 expires, for example, an RRC connection re-establishment is performed. T311 is started at the beginning of the RRC connection re-establishment procedure during cell re-selection and stops when cell re-selection is successful. When T311 expires, terminal 20 enters an RRC idle state.

[0042] An example of the RLM procedure in terminal 20 will be explained with reference to Figure 6. In terminal 20, when a lower layer (e.g., the functional unit of the physical layer) detects out-of-sync (degradation of wireless link quality), it notifies the upper layer (e.g., the functional unit of the RRC) of the out-of-sync indication.

[0043] Terminal 20 starts Timer T310 when it detects that N310 consecutive out-of-sync indications have been notified from a lower layer to a higher layer. Terminal 20 stops Timer T310 when it detects that N311 consecutive in-sync indications (wireless link normal notification) have been notified from a lower layer to a higher layer while Timer T310 is running. If Timer T310 expires, Terminal 20 determines that an RLF has occurred and executes the RRC connection re-establishment procedure.

[0044] The in-sync indication mentioned above is information that can be defined, for example, as follows:

[0045] "Upon request from higher layers, the UE provides to higher layers the periodic CSI-RS configuration indexes and / or SS / PBCH block indexes from the set q1~ and the corresponding radio link quality measurements that are larger than or equal to Qin" In other words, in-sync indication is based on a certain threshold Q. in The above wireless quality measurement values ​​are the P-CSI-RS index, or (or both), the SS / PBCH block index (hereinafter sometimes referred to as SSB). The P-CSI-RS index and SSB index in question are within the set "q1~". q1~ are parameters notified from the base station equipment 20 to the terminal 10 via RRC signaling, for example, by candidateBeamRSList for wireless link quality measurement. Note that wireless link quality may be RSRP or RSRQ.

[0046] The above out-of-sync indication is defined, for example, as follows:

[0047] "PHY in the UE provides an indication to higher layers when the radio link quality for all corresponding resource configurations in the set q0~ that the UE uses to assess the radio link quality is worse than the threshold Qout" In other words, the out-of-sync indication is a threshold Q at which the wireless link quality of all resources in the set "q0~" that terminal 20 uses for wireless link quality evaluation is determined. out This is information that is notified in cases worse than the specified condition. q0~ is a set of P-CSI-RS indices that are notified from the base station device 20 to the terminal 10 via RRC signaling, for example, by failureDetectionResources.

[0048] <Regarding the problems in Example 1> In the high-frequency band expected to be used in the wireless communication system of this embodiment, it is anticipated that a greater number of narrow beams will be used than in existing technologies. In that case, it is anticipated that consecutive out-of-sync indications and consecutive in-sync indications will occur almost infrequently, or that consecutive out-of-sync indications and consecutive in-sync indications will occur excessively frequently.

[0049] Consequently, it is anticipated that RLF may not be properly detected if existing counter values ​​(N310, N311, etc.) or timers (T310, T311, etc.) are used. Conversely, it is also anticipated that RLF may be detected excessively frequently. The details of Example 1, which addresses this issue, are described in detail below as Example 1-1 and Example 1-2.

[0050] <Example 1-1> In Example 1-1, a new value not listed in the existing specifications is used as the counter value (constant) to determine the wireless link quality. Examples 1-1-1 and 1-1-2 are described below as specific examples.

[0051] <Example 1-1-1> In Example 1-1-1, a value greater than that specified in an existing specification (e.g., Non-Patent Document 2) can be used for the value of N310. In addition to this, or instead, a value greater than that specified in an existing specification (e.g., Non-Patent Document 2) can be used for the value of N311.

[0052] For example, if an RRC message (RLF-TimersAndConstants) contains {1,2,3,4,6,8,10,20,30,40,50} as a candidate value for N310, then an RRC message containing {1,2,3,4,6,8,10,20,30,40,50} is notified from the base station device 10 to the terminal 20.

[0053] For example, terminal 20, since the frequency band of the serving cell is in the high frequency band (a frequency higher than a predetermined value), selects 40 as the largest N310 value from {1, 2, 3, 4, 6, 8, 10, 20, 30, 40, 50}, sets N310 = 40, and then executes the procedure shown in Figure 6.

[0054] Alternatively, for example, the base station device 10 may maintain a set of {1, 2, 3, 4, 6, 8, 10, 20, 30, 40, 50} as a set of candidate values ​​for N310 that can be transmitted in an RRC message (RLF-TimersAndConstants), select, for example, 40 from this set, and notify the terminal 20 of 40 in an RRC message (RLF-TimersAndConstants). Upon receiving N310=40, the terminal 20 uses N310=40 to perform, for example, the procedure shown in Figure 6.

[0055] By using a larger value for N310 than the conventional value, it is possible to avoid excessively frequent occurrences of "consecutive out-of-sync indications."

[0056] Furthermore, for example, an RRC message (RLF-TimersAndConstants) may contain {1,2,3,4,5,6,8,10,15,20,30} as a candidate value for N311, and an RRC message containing {1,2,3,4,5,6,8,10,15,20,30} is notified from the base station device 10 to the terminal 20.

[0057] Terminal 20, for example, since the serving cell's frequency band is in the high frequency band, selects 20 as the largest N311 value from {1, 2, 3, 4, 5, 6, 8, 10, 15, 20, 30}, sets N311 = 20, and then executes the procedure shown in Figure 6, for example.

[0058] Alternatively, for example, the base station device 10 may maintain a set of {1, 2, 3, 4, 5, 6, 8, 10, 15, 20, 30} as a set of candidate values ​​for N311 that can be transmitted in an RRC message (e.g., RLF-TimersAndConstants), select, for example, 20 from this set, and notify terminal 20 of 20 in an RRC message (RLF-TimersAndConstants). Upon receiving N311=20, terminal 20 uses N311=20 to perform, for example, the procedure shown in Figure 6.

[0059] By using a larger value for N311 than the conventional value, it is possible to avoid the occurrence of excessively frequent "consecutive in-sync indications."

[0060] <Example 1-1-2> In Example 1-1-2, a new RRC message (here, RLF-TimersAndConstants-r17) is introduced, allowing the base station device 20 to send a value larger than the value specified in existing specifications (e.g., Non-Patent Document 2) as the value of N310 to the terminal 10. In addition to this, or instead, the base station device 20 may also send a value larger than the value specified in existing specifications (e.g., Non-Patent Document 2) as the value of N311 to the terminal 10 using RLF-TimersAndConstants-r17.

[0061] For example, if RLF-TimersAndConstants-r17 includes {30,40,50} as a candidate value for N310, then RLF-TimersAndConstants-r17 containing {30,40,50} is notified from the base station device 10 to the terminal 20.

[0062] Terminal 20, for example, selects 40 as the largest N310 value from {30, 40, 50}, sets N310 = 40, and then executes the procedure shown in Figure 6.

[0063] Alternatively, for example, the base station device 10 may maintain {30, 40, 50} as a set of candidate values ​​for N310 that can be transmitted with RLF-TimersAndConstants-r17, select, for example, 40 from this set, and notify terminal 20 of 40 with RLF-TimersAndConstants-17. Upon receiving N310=40, terminal 20 uses N310=40 to perform, for example, the procedure shown in Figure 6.

[0064] By using a larger value for N310 than the conventional value, it is possible to avoid excessively frequent occurrences of "consecutive out-of-sync indications."

[0065] Furthermore, for example, if RLF-TimersAndConstants-r17 includes {15,20,30} as a candidate value for N311, then RLF-TimersAndConstants-r17 containing {15,20,30} is notified from the base station device 10 to the terminal 20.

[0066] Terminal 20, for example, selects 20 as the largest N311 value from {15, 20, 30}, sets N310 = 20, and then executes the procedure shown in Figure 6.

[0067] Alternatively, for example, the base station device 10 may maintain {15, 20, 30} as a set of candidate values ​​for N311 that can be transmitted with RLF-TimersAndConstants-r17, select, for example, 20 from this set, and notify terminal 20 of 20 with RLF-TimersAndConstants-17. Upon receiving N311=20, terminal 20 uses N311=20 to perform, for example, the procedure shown in Figure 6.

[0068] By using a larger value for N311 than the conventional value, it is possible to avoid the occurrence of excessively frequent "consecutive in-sync indications."

[0069] Whether or not terminal 20 uses the new RRC message (new field) described above may be set by the base station equipment 10 to terminal 20 via RRC configuration. Alternatively, whether or not terminal 20 uses the new RRC message (new field) described above may be determined by the carrier frequency or SCS of the cell in which terminal 20 is located. For example, the new RRC message described above is used when the carrier frequency (or SCS) is greater than a threshold.

[0070] <Examples 1-2> Next, we will describe Example 1-2. In Example 1-2, the trigger condition for starting the timer of T310 is changed from the condition described in Figure 6 above (the number of consecutive out-of-sync indications becomes N310).

[0071] Furthermore, in Example 1-2, the trigger condition for stopping the timer of T310 is changed from the condition described in Figure 6 above (the number of consecutive in-sync indications becomes N310). Examples 1-2-1 to 1-2-4 below are described as specific examples.

[0072] <Example 1-2-1> In Example 1-2-1, terminal 20 starts T310 when it detects X out-of-sync indications within Y. Y is, for example, the number of in-sync indications detected. Alternatively, Y may be a time length (for example, a time length in milliseconds). If Y is a time length, t304 may be used as the value of Y.

[0073] For example, terminal 20 will initiate T310 if it detects Y in-sync indications and X out-of-sync indications among them. Alternatively, terminal 20 will initiate T310 if it detects X out-of-sync indications within a time period of Y msec.

[0074] Alternatively, X may be a probability (%) of Y. In this case, for example, if terminal 20 detects Y in-sync indications and Z out-of-sync indications during a certain period, and Z × 100 / Y > X%, then terminal 20 starts T310.

[0075] In any of the above types of X and Y, the values ​​of X and Y are defined in the specifications, etc., and these values ​​may be held in advance by the terminal 20 (and base station equipment 10), or candidate values ​​for X and Y (or X and Y that the terminal 20 should use) may be set from the base station equipment 10 to the terminal 20 by RRC signaling or MAC signaling.

[0076] When setting candidate values ​​for X and Y from the base station device 10 to the terminal 20, for example, {1, 2, 3, 4, 5} is set as X (e.g., the number of out-of-sync indications) and {5, 10, 20, 30} is set as Y (e.g., the number of in-sync indications).

[0077] Furthermore, when candidate values ​​for X and Y are set from the base station device 10 to the terminal 20, the terminal 20 may select the value to use from among the candidate values, or the base station device 10 may notify the terminal 20 of MAC signaling or DCI specifying the value to be used.

[0078] By using the conditions with X and Y as a trigger to start the T310, as described above, it is possible to avoid accidentally starting the T310 (when the deterioration of the wireless link quality is not severe enough to trigger the T310).

[0079] Whether or not terminal 20 uses the new determination method using X and Y as described above may be set by the base station equipment 10 to terminal 20 via RRC configuration. Alternatively, whether or not terminal 20 uses the new determination method using X and Y as described above may be determined by the carrier frequency or SCS of the cell in which terminal 20 is located. For example, terminal 20 uses the new determination method using X and Y as described above when the carrier frequency (or SCS) is greater than a threshold.

[0080] <Example 1-2-2> In Example 1-2-2, the trigger condition for starting the timer of T310 is changed, specifically the method for counting out-of-sync indications within the condition described in Figure 6 above (the number of consecutive out-of-sync indications becomes N310). The modified counting method may be used within the condition described in Figure 6 above (the number of consecutive out-of-sync indications becomes N310), or it may be used in Example 1-2-1.

[0081] Example 1-2-2 will be described with reference to Figure 7. As shown in Figure 7, when terminal 20 detects an out-of-sync indication, it does not count out-of-sync indications detected in the time interval from the detection time to Z (msec) later, but counts out-of-sync indications from Z (msec) onward.

[0082] This avoids detecting excessively frequent and consecutive out-of-sync indications.

[0083] The value of Z is defined in the specifications, etc., and the terminal 20 (and base station equipment 10) may have these values ​​stored in advance, or candidate values ​​for Z (or Z that the terminal 20 should use) may be set from the base station equipment 10 to the terminal 20 by RRC signaling or MAC signaling.

[0084] Furthermore, when candidate values ​​for Z are set from the base station device 10 to the terminal 20, the terminal 20 may select the value to use from among the candidate values, or the base station device 10 may notify the terminal 20 of MAC signaling or DCI specifying the value to be used.

[0085] <Example 1-2-3> In Example 1-2-3, the trigger condition for stopping the timer of T310 is changed from the condition described in Figure 6 above (the number of consecutive in-sync indications becomes N310).

[0086] Specifically, terminal 20 stops T311 when it detects X in-sync indications within Y. Y is, for example, the number of out-of-sync indications detected. Alternatively, Y may be a time duration (for example, a time duration in milliseconds).

[0087] For example, terminal 20 stops T311 if it detects Y out-of-sync indications and X in-sync indications among them. Also, for example, terminal 20 stops T311 if it detects X in-sync indications within a time period of Y msec.

[0088] Alternatively, X may be a probability (%) of Y. In this case, for example, if terminal 20 detects Y out-of-sync indications and Z in-sync indications during a certain period, and Z × 100 / Y > X%, then terminal 20 will stop T311.

[0089] In any of the above types of X and Y, the values ​​of X and Y are defined in the specifications, etc., and these values ​​may be held in advance by the terminal 20 (and base station equipment 10), or candidate values ​​for X and Y (or X and Y that the terminal 20 should use) may be set from the base station equipment 10 to the terminal 20 by RRC signaling or MAC signaling.

[0090] Furthermore, when candidate values ​​for X and Y are set from the base station device 10 to the terminal 20, the terminal 20 may select the value to use from among the candidate values, or the base station device 10 may notify the terminal 20 of MAC signaling or DCI specifying the value to be used.

[0091] By using the conditions with X and Y as a trigger for stopping T311, as described above, it is possible to avoid accidentally stopping T311 (when the recovery of wireless link quality is not sufficient to warrant stopping T311).

[0092] Whether or not terminal 20 uses the new determination method using X and Y as described above may be set by the base station equipment 10 to terminal 20 via RRC configuration. Alternatively, whether or not terminal 20 uses the new determination method using X and Y as described above may be determined by the carrier frequency or SCS of the cell in which terminal 20 is located. For example, terminal 20 uses the new determination method using X and Y as described above when the carrier frequency (or SCS) is greater than a threshold.

[0093] <Example 1-2-4> In Example 1-2-4, the trigger condition for stopping the timer of T311 is changed by modifying the counting method of the in-sync indication, which is the condition described in Figure 6 above (the number of consecutive in-sync indications becomes N311). The modified counting method may be used in the condition described in Figure 6 above, or in Example 1-2-3.

[0094] Example 1-2-4 will be described with reference to Figure 7. In Figure 7, the out-of-sync indication will be replaced with the in-sync indication.

[0095] When terminal 20 detects an in-sync indication, it does not count in-sync indications detected during the time interval from the detection time to Z(msec) later, but counts in-sync indications from Z(msec) onward.

[0096] This avoids the detection of excessively frequent consecutive in-sync indications.

[0097] The value of Z is defined in the specifications, etc., and the terminal 20 (and base station equipment 10) may have these values ​​stored in advance, or candidate values ​​for Z (or Z that the terminal 20 should use) may be set from the base station equipment 10 to the terminal 20 by RRC signaling or MAC signaling.

[0098] Furthermore, when candidate values ​​for Z are set from the base station device 10 to the terminal 20, the terminal 20 may select the value to use from among the candidate values, or the base station device 10 may notify the terminal 20 of MAC signaling or DCI specifying the value to be used.

[0099] (Example 2) Next, we will describe Example 2. Example 2 is an example of a technique for detecting beam failures (BFD) and performing beam recovery (BFR). First, we will explain a basic example of operation in BFD / BFR in this embodiment with reference to Figures 8 and 9. Note that Figures 8 and 9 are basic operation examples common to all BFR embodiments.

[0100] First, referring to Figure 8, we will explain an example of BFD / BFR operation in PCell / PSCell (BFR of R-15).

[0101] In S10, terminal 20 receives a reference signal (CSI-RS, SSB, or both CSI-RS and SSB) transmitted from base station equipment 10 for each beam and measures its quality (RSRP, RSRQ, etc.). If terminal 20 determines that the quality of all reference signals (i.e., beams) has deteriorated a predetermined number of times, it performs the search for a new beam in S11.

[0102] In S10, all reference signals refer to a set of reference signals (indices) set from the base station device 10 to the terminal 20 for measurement in order to detect beam failure (failure detection resources), and this is called q0. For example, 8 is set for this.

[0103] In S11, terminal 20 measures the L1-RSRP of candidate reference signals (candidateBeamRSList, set by base station equipment 10 and referred to as q1) and selects the reference signal (beam) with the maximum L1-RSRP as the new beam.

[0104] In S12, terminal 12 transmits a PRACH (preamble) at the PRACH occasion corresponding to the selected new beam. Terminal 20 monitors the BFR response (PDCCH) in the BFR response window that starts 4 slots later.

[0105] Terminal 20, 28 symbols after receiving the BFR response (PDCCH) in S13, monitors the PDCCH in CORESET#0, assuming that the PDCCH monitored in CORESET#0 is in a QCL relationship with the new beam (reference signal).

[0106] Next, with reference to Figure 9, we will explain an example of BFD / BFR operation for SCell (BFR introduced in R-16). In Figure 9, we assume that SCell is provided by base station equipment 30.

[0107] In S21, terminal 20 receives a reference signal (CSI-RS, SSB, or both CSI-RS and SSB) transmitted from base station equipment 30 for each beam and measures its quality (RSRP, RSRQ, etc.). If terminal 20 determines that the quality of all reference signals (i.e., beams) has deteriorated, it sends an SR (Scheduled Request) in S21 when the number of times it has determined that the quality of all reference signals (i.e., beams) has deteriorated reaches a predetermined threshold, it also performs a search for a new beam in S23.

[0108] In S20, all reference signals refer to a set of reference signals (or their indices) set from the base station device 10 to the terminal 20 for detecting beam failure (failure detection resources), and this is called q0. For example, 8 is set for this.

[0109] In S23, terminal 20 measures the L1-RSRP of candidate reference signals (candidateBeamRSList, set by base station equipment 10 and referred to as q1) and selects the reference signal (beam) with the maximum L1-RSRP as the new beam.

[0110] In S22, terminal 20 receives a UL grant and uses the allocated resources to send a MAC CE in S24. The MAC CE includes the index of the CC where the beam failure occurred and the index of the new reference signal for each CC (i.e., the beam index). Terminal 20 receives a BFR response (PDCCH) in S25.

[0111] Terminal 20 monitors PDCCHs 28 symbols after receiving the PDCCH that schedules PUSCH (PDCCH of S25), assuming that subsequent PDCCHs monitored by SCell are in a QCL relationship with the new beam (reference signal). Furthermore, after the aforementioned 28 symbols, Terminal 20 transmits subsequent PUSCHs using SCell with a spatial domain filter corresponding to the spatial domain filter of the new beam (reference signal). In other words, it also updates the QCL for PUSCHs.

[0112] <Regarding the issues in Example 2> In the high-frequency bands intended for use in the wireless communication system of this embodiment, it is anticipated that a greater number of narrow beams will be used than in existing technologies. In such cases, the conditions for triggering BFR in existing technologies (e.g., the technologies described in the Rel-15 / -16 specifications) may not be efficient.

[0113] In existing technology, at S10 and S20 in Figure 8, terminal 20 triggers BFR (starts searching for a new beam) when it detects BFI_COUNTER ≥ beamFailureInstanceMaxCount before beamFailureDetectionTimer expires. Both beamFailureDetectionTimer and beamFailureInstanceMaxCount are parameters set by RRC from base station equipment 10 to terminal 10.

[0114] BFI_COUNTER is determined when the wireless link quality of all reference signals (beams) in q0 reaches the threshold (Q). out,LR This is a counter that increments (by 1) when the value becomes worse than [a certain value].

[0115] In existing technologies, the candidate values ​​for beamFailureInstanceMaxCount are {1, 2, 3, 4, 5, 6, 8, 10}, and one of these values ​​will be set for terminal 20 via RRC. Also, in existing technologies, the candidate values ​​for beamFailureDetectionTimer in RRC signaling are {1, 2, 3, 4, 5, 6, 8, 10}. If this value is, for example, k, then beamFailureDetectionTimer (the time duration as a timer) is "k × (the maximum value of {shortest periodicity of the P-CSI-RS configurations and / or SSB, 2 [mseq]})". In other words, {1, 2, 3, 4, 5, 6, 8, 10} times (RRC configurable) of the max. of {shortest periodicity of the P-CSI-RS configurations and / or SSB, 2 [mseq]}.

[0116] With existing technologies, the beamFailureInstanceMaxCount value may be too small, potentially triggering BFRs excessively frequently. This is identified as Problem 1.

[0117] Furthermore, since the P-CSI-RS / SSB period is slot-based, it is expected to be shorter than 2 msec when considering a wide SCS. Therefore, it is highly likely that k × 2 will be used as the beamFailureDetectionTimer (timer duration), in which case the beamFailureDetectionTimer (timer duration) may be too long. This will be referred to as Problem 2.

[0118] Below, an example illustrating the technology to solve Problem 1 will be described as Example 2-1, and a technology to solve Problem 2 will be described as Example 2-2.

[0119] <Example 2-1> In Example 2-1, the value set from the base station device 20 to the terminal 10 by the RRC message (beamFailureInstanceMaxCount) is made larger than the value described in existing specifications (e.g., Non-Patent Document 2). Examples 2-1-1 and 2-1-2 are described below.

[0120] <Example 2-1-1> For example, if an RRC message (beamFailureInstanceMaxCount) contains {1,2,3,4,5,6,8,10,20,25,30} as a candidate value, the RRC message containing {1,2,3,4,5,6,8,10,20,25,30} is notified from the base station device 10 to the terminal 20.

[0121] Terminal 20, for example, because the frequency band of the serving cell is in the high frequency band, selects 30 as the largest beamFailureInstanceMaxCount value from {1,2,3,4,5,6,8,10,20,25,30}, sets beamFailureInstanceMaxCount=30, and executes the steps in S10 of Figure 8 and S20 of Figure 9.

[0122] In cases where multiple candidate values ​​are set as described above, the base station device 10 may specify to the terminal 20, via MAC signaling or DCI, one value that the terminal 20 should use.

[0123] Alternatively, for example, the base station device 10 may maintain a set of {1, 2, 3, 4, 5, 6, 8, 10, 20, 25, 30} as a set of candidate values ​​that can be sent in an RRC message (beamFailureInstanceMaxCount), select, for example, 30 from this set, and notify terminal 20 of 30 in an RRC message (beamFailureInstanceMaxCount). Terminal 20 then uses beamFailureInstanceMaxCount=30 to perform, for example, the steps in S10 of Figure 8 and S20 of Figure 9.

[0124] <Example 2-1-2> In Example 2-1-2, a new RRC message (here, beamFailureInstanceMaxCount-r17) is introduced, allowing the base station device 20 to send a value larger than the value specified in existing specifications (e.g., Non-Patent Document 2) to the terminal 10 as the value of beamFailureInstanceMaxCount.

[0125] For example, if beamFailureInstanceMaxCount-r17 includes {20,25,30} as a candidate value, the beamFailureInstanceMaxCount-r17 containing {20,25,30} is notified from the base station device 10 to the terminal 20.

[0126] Terminal 20, for example, selects 30 from {20, 25, 30}, sets beamFailureInstanceMaxCount=30, and executes S10 in Figure 8 and S20 in Figure 9.

[0127] Alternatively, for example, the base station device 10 may maintain {20, 25, 30} as a set of candidate values ​​for N310 that can be transmitted with beamFailureInstanceMaxCount-r17, select, for example, 30 from this set, and notify terminal 20 of 30 with beamFailureInstanceMaxCount-r17. Terminal 20 then sets beamFailureInstanceMaxCount=30 and executes, for example, S10 in Figure 8 and S20 in Figure 9.

[0128] Using a large count value helps avoid falsely triggering the beam frame rate (BFR) due to minor beam degradation events.

[0129] Whether terminal 20 uses such large values ​​or new RRC messages (new fields) may be set by the base station equipment 10 to terminal 20 via RRC configuration. Alternatively, whether terminal 20 uses such large values ​​or new RRC messages (new fields) may be determined by the carrier frequency or SCS of the cell in which terminal 20 is located. For example, if the carrier frequency (or SCS) is greater than a threshold, such large values ​​or new RRC messages may be used.

[0130] <Example 2-2> In Example 2-2, the value of 2 [msec] in "k × (maximum value of {shortest periodicity of the P-CSI-RS configurations and / or SSB, 2 [msec]})" used to determine beamFailureDetectionTimer (the time duration as a timer) is replaced with a value smaller than 2 [msec]. Examples 2-2-1 and 2-1-2 are described below.

[0131] <Example 2-2-1> Terminal 20 uses a number smaller than 2 instead of 2 in "k × (maximum value of {shortest periodicity of the P-CSI-RS configurations and / or SSB, 2 [msec]})". For example, 0.1, 0.5, 1.0, or 1.5 can be used. The value to be used as the number smaller than 2 is specified in the specifications, and terminal 20 may store that value in advance, or it may be notified to terminal 20 from base station equipment 10 via RRC signaling, MAC signaling, or DCI.

[0132] Terminal 20 executes S10 in Figure 8 and S20 in Figure 9 using beamFailureDetectionTimer (time as a timer) determined by using a number smaller than 2 instead of 2 in "k × (maximum value of {shortest periodicity of the P-CSI-RS configurations and / or SSB, 2 [msec]})".

[0133] <Example 2-2-2> Example 2-2-2 introduces a new RRC message (a new field) that allows the use of a number smaller than 2 instead of 2 in "k × (maximum value of {shortest periodicity of the P-CSI-RS configurations and / or SSB, 2 [msec]})".

[0134] For example, if the new RRC message includes {0.1,0.5,1.0,1.5} as candidate values, the base station device 10 notifies the terminal 20 of the new RRC message containing {0.1,0.5,1.0,1.5}.

[0135] Terminal 20, for example, selects 0.5 from {0.1, 0.5, 1.0, 1.5} and uses 0.5 instead of 2 in "k × (maximum value of {shortest periodicity of the P-CSI-RS configurations and / or SSB, 2 [msec]})" to determine beamFailureDetectionTimer (time duration as a timer), and executes S10 in Figure 8 and S20 in Figure 9.

[0136] Alternatively, for example, the base station device 10 may maintain {0.1, 0.5, 1.0, 1.5} as a set of candidate values ​​that can be sent in a new RRC message, select, for example, 0.5 from this set, and notify terminal 20 of 0.5 in a new RRC message. Terminal 20 uses 0.5 to determine beamFailureDetectionTimer (the time duration as a timer) and executes S10 in Figure 8 and S20 in Figure 9.

[0137] Furthermore, the information notified from the base station device 10 to the terminal 20 in the new RRC message may be the beamFailureDetectionTimer (time duration as a timer) itself. Example 2-2-2 allows for faster BFR triggering.

[0138] Whether terminal 20 uses such small values ​​or new RRC messages (new fields) may be set by the base station equipment 10 to terminal 20 via RRC configuration. Alternatively, whether terminal 20 uses such small values ​​or new RRC messages (new fields) may be determined by the carrier frequency or SCS of the cell in which terminal 20 is located. For example, if the carrier frequency (or SCS) is greater than a threshold, such small values ​​or new RRC messages may be used.

[0139] (Example 3) Example 3 is carried out in combination with Example 1 or Example 2. Example 3 may also be carried out in combination with both Example 1 and Example 2.

[0140] Since the 52.6 to 71 GHz frequency band intended for use in the wireless communication system of this embodiment includes the unlicensed spectrum (unlicensed band), LBT may be required in the wireless communication system of this embodiment.

[0141] In the RLM and BFR in Examples 1 and 2, the terminal 20 receives a reference signal (CSI-RS, SSB, or CSI-RS and SSB) periodically transmitted from the base station device 10 and performs quality measurement.

[0142] However, when LBT is performed in the base station device 10, for example, as shown in Figure 10, LBT may succeed or fail at each transmission timing of the reference signal. As a result, it may become impossible to periodically transmit the reference signal from the base station device 10, and it is expected that the frequency at which the terminal 20 can receive the reference signal will decrease. Therefore, RLM and BFR may not be able to be performed properly. In particular, when using the large count values ​​described in Examples 1 and 2, RLM and BFR may not be able to be performed properly.

[0143] Therefore, in Example 3, in Example 1 (RLM / RLF) and Example 2 (BFD / BFR), the terminal 20 and base station 10 use the criteria for LBT to determine whether or not to perform processing using the new parameters etc. described in Example 1 (RLM / RLF) and Example 2 (BFD / BFR). Basically, processing using the new parameters etc. described in Example 1 (RLM / RLF) and Example 2 (BFD / BFR) is performed when LBT is not performed. The criteria for determination are as follows, for example.

[0144] (1) Is it necessary to implement LBT?

[0145] (2) The latest results on whether LBT was successful or not.

[0146] (3) Whether the slot (the slot that performs RLM / RLF and BFD / BFR processing) is within the COT (channel occupancy).

[0147] For example, (1) whether or not LBT is necessary is determined by the terminal 20 and the base station 10, respectively, based on whether the frequency band used is an unlicensed band or a licensed band. Alternatively, the terminal 20 and the base station 10 can also determine whether or not LBT is necessary based on whether or not the frequency band used is a band that requires LBT.

[0148] (2) The terminal 20 and the base station 10 can each obtain the latest result regarding whether or not LBT was successful as a result of their own LBT execution.

[0149] (3) Whether a slot is within the COT (channel occupancy time) can be determined by the terminal 20 and the base station device 10, which set the COT from their own LBT results. The terminal 20 can also determine this from, for example, the DCI information received from the base station device 10. Examples 3-1 to 3-3 below will be explained as specific examples of using the determination criteria.

[0150] <Example 3-1: RLM / RLF> Example 3-1 consists of Example 3-1-1 and Example 3-1-2.

[0151] <Example 3-1-1> Example 3-1-1 is based on Example 1-1-2 as an example. Terminal 20 and base station device 10 each determine whether or not LBT is necessary. If LBT is not necessary, the base station device 10 notifies terminal 20 of a large counter value (N310 or N311, or both N310 or N311) using the new RRC message (here, RLF-TimersAndConstants-r17) described in Example 1-1-2, and terminal 20 uses this counter value to execute RLM / RLF. If LBT is to be executed, for example, the existing RLF-TimersAndConstants is used. With Example 3-1-1, RLM / RLF can be executed appropriately even when LBT is being executed.

[0152] <Example 3-1-2> Example 3-1-2 is based on Example 1-2-1 as an example. In Example 1-2-1, terminal 20 starts T310 when it detects X out-of-sync indications within Y.

[0153] In Example 3-1-2, which considers LBT, if the frequency band being used is an unlicensed band, when terminal 20 detects that base station equipment 10 has failed LBT, terminal 20 uses a value for X that is greater than the threshold (X_unlic). For example, it uses a value greater than the threshold (X_unlic) from the candidate values ​​for X set by base station equipment 10. If terminal 20 does not detect that base station equipment 10 has failed LBT, it may perform the operation as described in Example 1-2-1.

[0154] Terminal 20 may be aware that the base station device 10 has failed to perform LBT through a notification from the base station device 10, by not receiving the signal that should be transmitted from the base station device 10, or by any other method.

[0155] Alternatively, if the base station device 10 fails to perform LBT, it may notify the terminal 20 of a value of X greater than the threshold (X_unlic), and the terminal 20 may use that value of X.

[0156] The threshold value (X_unlic) is specified in the specifications and may be held in advance by the terminal 20 and the base station device 10, or it may be notified from the base station device 10 to the terminal 20 by RRC signaling, MAC signaling, or DCI. Example 3-1-2 allows for proper execution of RLM / RLF even in situations where LBT failures occur.

[0157] <Example 3-2: BFD / BFR> Example 3-2 is based on Example 2-1-2 as an example. Terminal 20 and base station device 10 each determine whether or not it is necessary to perform LBT. If it is determined that LBT is not necessary, the base station device 10 notifies terminal 20 of a large counter value using the new RRC message described in Example 2-1-2 (here, beamFailureInstanceMaxCount-r17), and terminal 20 performs RFR / BFD using that counter value. If it is necessary to perform LBT, for example, beamFailureInstanceMaxCount is used.

[0158] Example 3-1-2 allows us to avoid using large values ​​when LBT is required.

[0159] <Example 3-3: RLM, BFR> Example 3-3 may be based on either Example 1 (RLM) or Example 2 (BFR). Furthermore, Example 3-3 may be applied to existing RLM and BFR independently of Example 1 (RLM) and Example 2 (BFR).

[0160] In Example 3-3, when LBT is required (i.e., when using an unlicensed band), terminal 20 uses a non-periodic reference signal instead of a periodic reference signal as the reference signal used for beam monitoring / selection in RLM or BFR. Examples of non-periodic reference signals include A-CSI-RS, SP-CSI-RS, PDCCH, etc.

[0161] For example, when terminal 20 and base station equipment 10 use an unlicensed band, base station equipment 10 transmits a non-periodic reference signal to terminal 10. For example, base station equipment 10 transmits the reference signal when LBT is successful.

[0162] Terminal 10 performs RLM and BFR by measuring a non-periodically received reference signal and performing counting processes, for example, as described in Figures 6, 8, and 9. According to Embodiment 3, when LBT is required, RLF and BFR can be properly executed without being affected by LBT failure.

[0163] (Example 4) Next, Example 4 will be described. Regarding BFD / BFR in PCell / PSCell as described with reference to Figure 8, in existing technology (e.g., Non-Patent Document 3), when terminal 20 transmits a PRACH in slot n to notify of a new beam (new reference signal), it starts monitoring the PDCCH (PDCCH of CORESET#0) in the search space specified by recoverySearchSpaceId from slot n+4. This PDCCH and its corresponding PDSCH are in a QCL relationship with the new beam (reference signal).

[0164] In the high-frequency band assumed in this embodiment, a wide SCS is expected to be used, resulting in a very short time length for the four slots. Therefore, the base station device 10 may not be able to prepare and transmit the PDCCH to be transmitted in the search space specified by recoverySearchSpaceId.

[0165] Therefore, in Example 4, when using a high-frequency band (for example, a frequency higher than 52.6 GHz) as the frequency band for BFR for PCell / PSCell, the number of slots from PRACH transmission to the start of PDCCH monitoring is made greater than 4.

[0166] In other words, as shown in Figure 11, a value greater than 4 is used for X, which is the number of slots from when terminal 20 sends PRACH in S201 until it starts monitoring PDCCH in S202. From the perspective of the base station equipment, the base station equipment 10 sends PDCCH a number of slots greater than 4 after receiving PRACH from terminal 20. Specifically, there are the following embodiments 4-1, 4-2, and 4-3.

[0167] <Example 4-1> In Example 4-1, a value greater than 4 is specified for X in the specifications, and the terminal 20 and base station device 10 each hold this value for X. When using a frequency band higher than 52.6 GHz, for example, the terminal 20 and base station device 10 each perform BFR using the value they hold for X. Values ​​greater than 4 that can be used for X include, for example, 8, 16, 32, etc.

[0168] <Example 4-2> In Example 4-2, a value different from 4 is used for X depending on the conditions. Example 4-2 has the following variations (Examples 4-2-1 to 4-2-4).

[0169] <Example 4-2-1> In Example 4-2-1, the value of X to be used is determined according to the SCS. For example, terminal 20 and base station equipment 10 use 4 as X when the SCS of the cell targeted by BFR is 15kHz, 30kHz, or 60kHz, and use a value greater than 4 as X when the SCS is greater than 60kHz (i.e., 120 / 240 / 480 / 960kHz, etc.).

[0170] <Example 4-2-2> In Example 4-2-12, the value of X to be used is determined according to the frequency range (FR). For example, terminal 20 and base station equipment 10 use 4 as X if the FR of the cell subject to BFR is FR1 or FR2, and use a value greater than 4 as X if the FR is FR4.

[0171] <Example 4-2-3> In Example 4-2-3, the value of X to be used is determined according to the capabilities (UE capability) of terminal 20. For example, if terminal 20 and base station device 10 detect that terminal 20's capability is such that only X value of 4 can be used, they will use X value of 4. If terminal 20's capability is such that X values ​​other than 4 can also be used, they will use a value other than 4 for X (as necessary). The determination of what is necessary can be made using the methods of Example 4-2-1 or Example 4-2-2.

[0172] <Example 4-2-4> In Example 4-2-4, the terminal 20 and the base station device 10 each use the value of X notified from the base station device 10 to the terminal 20 via RRC signaling (or MAC signaling or DCI).

[0173] In Examples 4-2-1 to 4-2-3, the value used as X according to each condition may be notified from the base station device 10 to the terminal 20 via RRC signaling (or MAC signaling, or DCI), set in the terminal 20 via SIM, or specified in the specifications.

[0174] <Example 4-3> In Example 4-3, the value of X is "4 + offset". The offset value can be negative, zero, or positive.

[0175] The offset value (for example, one or more candidate values) is defined in the specifications, and the terminal 20 and the base station equipment 10 each hold this value in advance. Alternatively, the offset value (for example, one or more candidate values) is set (or pre-set) by the base station equipment 10 to the terminal 20 using RRC or the like.

[0176] For example, if information indicating the offset value that terminal 20 should use is notified to terminal 20 from base station equipment 10 via RRC signaling, MAC signaling, or DCI, terminal 20 will perform BFR using "4 + offset" as the value of X.

[0177] In addition, in any of Examples 4-1, 4-2, and 4-3, if the RRC (Routing Control Relay) is configured from the base station device 10 to the terminal 20 to perform the operations of Examples 4-1 / 4-2 / 4-3, the base station device 10 and the terminal 20 may perform the operations of Examples 4-1 / 4-2 / 4-3. Furthermore, the decision to perform the operations of Examples 4-1 / 4-2 / 4-3 may be made according to the capabilities (UE capability) of the terminal 20.

[0178] (Example 5) Next, Example 5 will be described. Regarding BFD / BFR in PCell / PSCell as described with reference to Figure 8, in existing technology, when terminal 20 transmits a PRACH in slot n to notify of a new beam (new reference signal), it starts monitoring the PDCCH in the search space specified by recoverySearchSpaceId from slot n+4. 28 symbols after receiving the BFR response (first PDCCH), it is assumed that the PDCCH monitored in CORESET#0 is in a QCL relationship with the new beam (reference signal), and CORESET#0 monitors the PDCCH. In other words, 28 symbols after receiving the BFR response (first PDCCH), the QCL of the PDCCH in CORESET#0 is updated to have a QCL relationship with the new beam.

[0179] Furthermore, in the BFD / BFR in SCell as explained with reference to Figure 9, in existing technology, after the terminal 20 transmits a MAC CE notifying of a new beam via PUSCH, it receives a BFR response (PDCCH) and then, 28 symbols later, monitors the PDCCH of the SCell monitored in all CORESEs, assuming that it is in a QCL relationship with the new beam (reference signal).

[0180] Furthermore, after the 28 symbols mentioned above, the PUSCH transmitted by the PUCCH-SCell will use a spatial domain filter corresponding to the spatial domain filter of the new beam (reference signal).

[0181] In other words, 28 symbols after receiving the BFR response (PDCCH), the QCLs of PDCCH and PUSCH are updated to have a QCL relationship with the new beam.

[0182] Figure 12 shows the above 28 symbols represented as Y symbols. In S301, terminal 20 transmits PRACH (MAC CE in PUSCH in BFD / BFR in SCell). In S302, terminal 20 receives the BFR response and updates the QCL after the Y symbol.

[0183] As mentioned above, in existing technology, Y is 28. However, for wide SCS used in high-frequency bands, i.e., short symbol lengths, the time from receiving the BFR response to 28 symbols later may be too short for QCL updating.

[0184] Conversely, considering the numerous narrow beams expected to be used in the high-frequency band, BFRs are expected to occur frequently. Under this assumption, the time interval of 28 symbols after receiving a BFR response may be too long, potentially preventing rapid beam changes.

[0185] Therefore, in Example 5, as explained in Examples 5-1 to 5-3 below, a value other than 28 can be used for Y.

[0186] <Example 5-1> In Example 5-1, a value greater than 28 (one or more candidate values) for Y is specified in the specifications, and the terminal 20 and base station equipment 10 each hold this value in advance. Alternatively, a value greater than 28 (one or more values) for Y is set (or pre-set) by RRC or the like from the base station equipment 10 to the terminal 20. Furthermore, a value greater than 28 (one or more values) for Y may be notified by MAC signaling, DCI, or the like from the base station equipment 10 to the terminal 20.

[0187] Examples 5-1-1 to 5-1-3 describe a method for determining the actual value of Y to be used from among the candidate values.

[0188] <Example 5-1-1> The base station device 10 and the terminal 20 each use a specific value (e.g., 56) as Y when the SCS of the cell targeted for BFR is greater than a threshold (e.g., 120 kHz).

[0189] <Example 5-1-2> The base station device 10 and the terminal 20 each use a specific value (e.g., 56) as Y when the carrier frequency of the cell targeted by BFR is greater than a threshold (e.g., 52.6 GHz).

[0190] <Example 5-1-3> The base station device 10 and the terminal 20 will, if they detect that the terminal 20's UE capability is such that only Y = 28 is available, use Y = 28. If they detect that Y is capable of using a value other than 28, they will use a value other than 28 (e.g., 56) as needed. For determining whether Y is available as needed, Examples 5-1-1 and 5-1-2 can be used.

[0191] <Example 5-2> In Example 5-2, the value of Y is specified in the specifications, etc., as a value smaller than 28 (one or more candidate values), and the terminal 20 and the base station device 10 each hold this value in advance. Alternatively, the value of Y is set (or pre-set) by the base station device 10 to the terminal 20 using RRC or the like. Furthermore, the value of Y is notified by the base station device 10 to the terminal 20 using MAC signaling, DCI, or the like.

[0192] Examples 5-2-1 to 5-2-4 describe a method for determining the actual value of Y to be used from among the candidate values.

[0193] <Example 5-2-1> The base station device 10 and the terminal 20 each use a specific value (e.g., 0 or 14) as Y when the SCS of the cell targeted for BFR is greater than a threshold (e.g., 120 kHz).

[0194] <Example 5-2-2> The base station device 10 and the terminal 20 each use a specific value (e.g., 0 or 14) as Y when the carrier frequency of the cell targeted by BFR is greater than a threshold (e.g., 52.6 GHz).

[0195] <Example 5-2-3> The base station device 10 and the terminal 20 will each use 28 as Y if they detect that the terminal 20's UE capability is such that only 28 can be used as Y, and will use a value other than 28 (e.g., 0 or 14) as Y as necessary if they detect that the terminal 20 has the capability to use a value other than 28 as Y. For making this determination as necessary, Examples 5-2-1, 5-2-2, and 5-2-4 can be used.

[0196] <Example 5-2-4> The base station equipment 10 and the terminal 20 each use a specific value (e.g., 0 or 14) as Y when the number of SSB, CSI-RS, or SRS beams of the cell targeted by BFR is greater than a threshold (e.g., 32 or 64).

[0197] <Example 5-3> In Example 5-3, the value of Y is "28 + offset". The offset value can be negative, zero, or positive.

[0198] The offset value (for example, one or more candidate values) is defined in the specifications, and the terminal 20 and the base station equipment 10 each hold this value in advance. Alternatively, the offset value (for example, one or more candidate values) is set (or pre-set) by the base station equipment 10 to the terminal 20 using RRC or the like.

[0199] For example, if information indicating the offset value that terminal 20 should use is notified to terminal 20 from base station equipment 10 via RRC signaling, MAC signaling, or DCI, terminal 20 will perform BFR (Figure 12) using "28 + offset" as the value of Y. In addition to the offset, a beam switching gap may be added to 28 symbols.

[0200] In Example 5 as a whole, the QCL update (updating to have a QCL relationship with the new beam) may be performed on any or more of the PDCCH, PUCCH, PDSCH, and PUSCH (or all of them).

[0201] In addition, in any of Examples 5-1, 5-2, and 5-3, if the RRC (Routing Control Relay) is configured to perform the operations of Examples 5-1 / 5-2 / 5-3 from the base station device 10 to the terminal 20, the base station device 10 and the terminal 20 may perform the operations of Examples 5-1 / 5-2 / 5-3. Furthermore, the decision to perform the operations of Examples 5-1 / 5-2 / 5-3 may be made according to the capabilities (UE capability) of the terminal 20.

[0202] (Example 6) Example 6 can be implemented in combination with any of the other examples. As explained in S11 of Figure 8 and S23 of Figure 9, when terminal 20 detects a BF, it searches for the best beam from the set of candidate beams (specifically, the index of the reference signal) included in candidateBeamRSList (referred to as q1). However, in the conventional technology, the number of candidate beams (reference signals) included in q1 is a maximum of 64.

[0203] In the high-frequency band assumed in this embodiment, it is expected that more beams will be used, so a maximum q1 of 64 may be insufficient for detecting an appropriate beam during BFR.

[0204] Therefore, in Example 6, in high-frequency band cells (e.g., 52.6 GHz or higher), more candidate beams can be included in q1.

[0205] The candidate beams to be included in q1 are specified in the specifications, etc., and may be held in advance by the terminal 20 and the base station equipment 10, or they may be set from the base station equipment 10 to the terminal 20 via RRC signaling, or instructions may be given from the base station equipment 10 to the terminal 20 via MAC signaling or DCI. In addition, the number of candidate beams to be included in q1 may match the number of CSI-RS beams, or match the number of CSI-RS beams and SSB beams.

[0206] By including more than 64 candidate beams in q1, terminal 20 can select a more appropriate narrow beam during BFR.

[0207] If q1 is not set on the terminal by RRC, terminal 20 may generate q1 based on certain rules. For example, terminal 20 may include all CSI-RS resource IDs (i.e., CSI-RS beams) set on terminal 20 in q1.

[0208] Furthermore, the number of q0 can also be increased. Specifically, this is as follows:

[0209] As explained in S10 of Figure 8 and S20 of Figure 9, terminal 20 determines whether the quality of all beams (specifically, the index of the reference signal) included in failureDetectionResources (referred to as q0) has deteriorated. However, in conventional technology, the number of beams (reference signals) included in q0 is a maximum of 8.

[0210] In the high-frequency band assumed in this embodiment, it is expected that more beams will be used, so a maximum q0 of 8 may be insufficient for properly detecting BF during BFR.

[0211] Therefore, in this embodiment, in high-frequency band cells (e.g., 52.6 GHz or higher), more beams can be included in q0.

[0212] Candidate beams to be included in q0 may be specified in the specifications, etc., and may be held in advance by the terminal 20 and the base station equipment 10, or they may be set from the base station equipment 10 to the terminal 20 via RRC signaling, or instructions may be given from the base station equipment 10 to the terminal 20 via MAC signaling or DCI.

[0213] Furthermore, the number of beams included in q0 may be associated with the number of CORSETs set for each BWP. For example, the number of beams included in q0 may be associated with the number of reference signals that have a QCL relationship with PDCCH.

[0214] By including more than 8 beams in q0, we can avoid detecting BFs excessively frequently.

[0215] Furthermore, if the RRC (Routing Control Code) is configured to apply Example 6 from the base station device 10 to the terminal 20, the base station device 10 and the terminal 20 may apply Example 6. Also, the application of Example 6 may be done according to the capabilities (UE capability) of the terminal 20.

[0216] (Example 7) Next, Example 7 will be described. Example 7 can be implemented in combination with any of the other examples.

[0217] In this embodiment, when performing carrier aggregation with multiple CCs, the base station device 10 and the terminal 20 may use one or more beams simultaneously across multiple CCs. In other words, the terminal 20 and the base station device 20 may use the same beam simultaneously across multiple CCs to transmit and receive signals. In that case, a beam failure (BF) in one CC means that a beam failure (BF) has also occurred in one or more other CCs.

[0218] Therefore, in Example 7, in the BFR procedure described in Figure 8 or Figure 9 for a certain cell (CC), after receiving a BFR response from the base station equipment 10, the terminal 20 applies the selected beam in the CC (the CC targeted by the BFR procedure) to a set of one or more other CCs. In other words, the terminal 20 updates the QCL relationship of the PDCCH (PDCCH and PUCCH of the SCell) in the CC (the CC targeted by the BFR procedure), and also performs a QCL update based on the new beam for one or more other CCs performing carrier aggregation, in the same way as the QCL update in the CC (the CC targeted by the BFR procedure).

[0219] From the perspective of the base station device 10, the base station device 10 transmits a PDCCH in the CC (the CC subject to the BFR procedure) using the same beam as the new beam reported from the terminal 20, and also transmits a PDCCH in one or more other CCs using the same beam as the new beam reported from the terminal 20, and receives a PUCCH.

[0220] More specifically, for example, let's assume that terminal 20 (and base station equipment 10) are using CC#A to #C as shown in Figure 13. In this case, if terminal 20 performs BFR on CC#A and selects beam #1, then beam #1 will be applied not only to CC#A but also to CC#B and CC#C. In other words, for example, base station equipment 10 transmits PDCCH with beam #1 not only on CC#A but also on CC#B and CC#C, and terminal 20 performs QCL updates based on beam #1 not only on CC#A but also on CC#B and CC#C.

[0221] The set of one or more CCs to which the beam selected by a CC subject to the BFR procedure is applied (including the CC subject to the BFR procedure) may be, for example, all CCs set up at terminal 20 (see example in Figure 13). The set of one or more CCs to which the beam selected by a CC subject to the BFR procedure is applied may also be set up for terminal 20 by RRC signaling.

[0222] The set of one or more CCs (including the CC targeted by the BFR procedure) to which the beam selected by a CC targeted by the BFR procedure is applied may be a set of CCs at a specific carrier frequency. A specific carrier frequency is, for example, a carrier frequency greater than 30 GHz, or a carrier frequency not included in FR1, or a carrier frequency greater than 52.6 GHz. Alternatively, the set of one or more CCs (including the CC targeted by the BFR procedure) to which the beam selected by a CC targeted by the BFR procedure is applied may be a set of CCs included in the applicable-CC-List.

[0223] Furthermore, in Example 7, in the beam selection described in S11 of Figure 8 and S23 of Figure 9, terminal 20 may select the best beam by measuring the L1-RSRP of all CC candidate beams set for terminal 20, or it may select the best beam by measuring the L1-RSRP of CC candidate beams of one or more specific cells (e.g., special cell) set for terminal 20 by RRC signaling.

[0224] Alternatively, terminal 20 may select the best beam by measuring the L1-RSRP of one or more candidate CC beams at a specific carrier frequency. A specific carrier frequency is, for example, a carrier frequency greater than 30 GHz, or a carrier frequency not included in FR1, or a carrier frequency greater than 52.6 GHz.

[0225] Furthermore, if the RRC (Routing Control Center) is configured to apply Example 7 from the base station device 10 to the terminal 20, the base station device 10 and the terminal 20 may apply Example 7. Also, the application of Example 7 may be done according to the capabilities (UE capability) of the terminal 20.

[0226] (Example 8) Next, Example 8 will be described. Example 8 can be implemented in combination with any of the other examples.

[0227] In both BFRs shown in Figures 8 and 9, the conventional technology allows terminal 20 to select and report only one new beam to base station equipment 10. However, from the perspective of base station equipment 10 understanding the status of the beams received by terminal 20, it is desirable for terminal 20 to report multiple beams obtained as a result of the search to base station equipment 10.

[0228] Therefore, in Example 8, for example, in S12 in Figure 8 or S24 in Figure 9, the terminal 20 reports to the base station device 10 the multiple beams (for example, two beams, specifically the indices of two reference signals) detected by beam search (S11 in Figure 8 or S23 in Figure 9).

[0229] The number of beams that terminal 20 reports to base station equipment 10 may be, for example, the number set by RRC signaling from base station equipment 10 to terminal 20. Alternatively, terminal 20 may decide the number of beams that it reports to base station equipment 10. Specific examples are as follows.

[0230] Based on the measured L1-RSRP, terminal 20 selects the top X beams with the best quality. If the difference in L1-RSRP among these X beams is within Y, terminal 20 reports the single best beam to base station equipment 10. If the difference in L1-RSRP among these X beams is not within Y, terminal 20 reports all X beams.

[0231] X and Y may be specified in the specifications, set via RRC from the base station device 10 to the terminal 20, or determined according to the capabilities of the terminal 20.

[0232] <Regarding sending methods> For example, in the BFR procedure shown in Figure 9, terminal 20 transmits multiple beams to the MAC CE that reports in S24.

[0233] Figure 14 shows an example of MAC CE. When reporting only one beam, terminal 20 places a bit in the B (MSB) of Oct2 to indicate that only one beam is being reported. In this case, Oct3 and beyond may not be present.

[0234] When reporting multiple beams, terminal 20 inserts a bit in the B (MSB) of Oct2 to indicate that the next beam will be reported in the next bit sequence (Oct3), and inserts the beam ID (reference signal ID) in the example bit of Oct2. The process continues similarly thereafter.

[0235] In the case of BFR for PCell / PSCell shown in Figure 8, for example, using 2-step RACH, the report data (MAC CE above) is sent along with PRACH in the MsgA transmission step.

[0236] Alternatively, in the case of BFRs for PCell / PSCell shown in Figure 8, the PRACH sequence may include information about multiple beams and transmit it.

[0237] For example, as shown in Figure 15, a PRACH sequence is associated with one or more beam IDs. The association information in Figure 15 may be specified in a specification document and pre-held by the terminal 20 and the base station equipment 10, or it may be set from the base station equipment 10 to the terminal 20 via RRC signaling.

[0238] Terminal 20 generates and transmits a PRACH sequence corresponding to the beam to be reported, based on the information in the table in Figure 15.

[0239] Furthermore, in order to reduce the number of PRACH sequences, the combination of information shown in Figure 15 may be configured via RRC signaling from the base station device 10 to the terminal 20. A combination would be, for example, associating "P-CSI-RS#1, #2, #3, #4" with PRACH sequence #1. Applying such combinations may also be configured via RRC signaling from the base station device 10 to the terminal 20.

[0240] <Applying 2-Step RACH> In the case of the PCell / PSCell BFR shown in Figure 8, a two-step RACH may be used to report multiple beams.

[0241] An example of a two-step RACH is shown in Figure 16. Although Figure 16 shows CBRA (Contention-based Random Access) as an example, two-step RACH can also be applied to CFRA (Contention-free Random Access). Example 8 may be applied to either CBRA or CFRA.

[0242] In S110, terminal 20 transmits MessageA (MsgA), which contains a preamble (PRACH) and data (PUSCH), to base station device 10. Here, the preamble and data correspond to, for example, Msg1 and Msg3 in a 4-step RACH.

[0243] In S120, the base station device 10 sends MessageB (MsgB) to the user terminal 20. The content of MsgB corresponds, for example, to Msg2 and Msg4 in the 4-step RACH.

[0244] The above S120 corresponds to the PRACH transmission in S12 in Figure 8, and S120 corresponds to the reception of the BFR response in S13 in Figure 8.

[0245] In Example 8, terminal 20 includes one or more beam IDs in MsgA. In addition to beam IDs, it may also include measurement results (L1-RSRP) for each beam.

[0246] Furthermore, terminal 20 may report the best beam via MsgA's PRACH and the second best beam (and subsequent beams) via MsgA's PUSCH using MAC CE. Also, terminal 20 may choose not to report the second best beam if the difference in L1-RSRP between the best beam and the second best beam is greater than threshold X. Also, terminal 20 may choose not to report the second best beam if its L1-RSRP is lower than threshold Y.

[0247] Terminal 20 may choose not to provide a field for reporting the beam to MAC CE if it does not report a second beam, or it may provide a field but leave its contents empty.

[0248] X and Y may be specified in the specifications, set via RRC from the base station equipment 10 to the terminal 20, or determined according to the capabilities of the terminal 20. Also, Y may be Q in,LR That's fine. Q in,LR This is the threshold used to determine whether the beam is in-sync (i.e., normal).

[0249] In Example 8, in a BFR, multiple beams obtained by beam search can be reported from terminal 20 to base station equipment 20 only when necessary.

[0250] (Device configuration) Next, we will describe an example of the functional configuration of the base station device 10 and terminal 20 that perform the processes and operations described above.

[0251] <Base station device 10> Figure 17 shows an example of the functional configuration of the base station device 10. As shown in Figure 17, the base station device 10 has a transmitting unit 110, a receiving unit 120, a setting unit 130, and a control unit 140. The functional configuration shown in Figure 17 is merely an example. The names of the functional categories and functional units can be anything as long as they can perform the operations according to the embodiment of the present invention. Also, the transmitting unit 110 and the receiving unit 120 may be collectively referred to as the communication unit.

[0252] The transmitting unit 110 includes the function of generating a signal to be transmitted to the terminal 20 and transmitting the signal wirelessly. The receiving unit 120 includes the function of receiving various signals transmitted from the terminal 20 and obtaining information from the received signals, for example, information from a higher layer. The transmitting unit 110 also has the function of transmitting NR-PSS, NR-SSS, NR-PBCH, DL / UL control signals, DCI via PDCCH, data via PDSCH, etc. to the terminal 20.

[0253] The setting unit 130 stores pre-configured setting information and various setting information to be transmitted to the terminal 20 in a storage device provided by the setting unit 130, and reads it from the storage device as needed.

[0254] The control unit 140 schedules DL reception or UL transmission of terminal 20 via the transmission unit 110. The control unit 140 also includes a function for LBT (Low-Block Transmission). The functions related to signal transmission in the control unit 140 may be included in the transmission unit 110, and the functions related to signal reception in the control unit 140 may be included in the reception unit 120. The transmission unit 110 may also be called a transmitter, and the reception unit 120 may be called a receiver.

[0255] <Terminal 20> Figure 18 shows an example of the functional configuration of terminal 20. As shown in Figure 18, terminal 20 has a transmitting unit 210, a receiving unit 220, a setting unit 230, and a control unit 240. The functional configuration shown in Figure 12 is merely an example. Any functional classification and name of functional unit is acceptable as long as it can perform the operations according to the embodiment of the present invention. The transmitting unit 210 and the receiving unit 220 may be collectively referred to as the communication unit.

[0256] The transmission unit 210 creates a transmission signal from the transmission data and wirelessly transmits the transmission signal. The reception unit 220 wirelessly receives various signals and acquires signals of higher layers from the received physical layer signals. Further, the reception unit 220 has a function of receiving NR-PSS, NR-SSS, NR-PBCH, DL / UL / SL control signals, DCI by PDCCH, data by PDSCH, etc. transmitted from the base station apparatus 10. Also, for example, as D2D communication, the transmission unit 210 transmits PSCCH (Physical Sidelink Control Channel), PSSCH (Physical Sidelink Shared Channel), PSDCH (Physical Sidelink Discovery Channel), PSBCH (Physical Sidelink Broadcast Channel), etc. to another terminal 20, and the reception unit 120 may receive PSCCH, PSSCH, PSDCH, or PSBCH, etc. from another terminal 20.

[0257] The setting unit 230 stores various setting information received from the base station apparatus 10 or another terminal by the reception unit 220 in a storage device included in the setting unit 230 and reads it out from the storage device as necessary. Also, the setting unit 230 stores preset setting information. The control unit 240 controls the terminal 20. Also, the control unit 240 includes a function of performing LBT.

[0258] <Summary> According to the present embodiment, at least a terminal, a base station apparatus, and a beam failure recovery method shown in the following items are provided.

[0259] <Configuration related to Examples 1 and 3> (Item 1) a reception unit that measures the quality of a wireless link; a control unit that starts a timer when the number of times of continuously detecting a wireless link quality degradation notification reaches a first threshold value, and determines whether the number of times of continuously generating a wireless link quality normal notification reaches a second threshold value before the timer expires; The first threshold or the second threshold is a value greater than a predetermined value. Terminal. (Section 2) If the carrier frequency or SCS in the monitored cell is greater than a predetermined value, the control unit uses a value greater than the predetermined value as the first threshold or the second threshold. The terminal described in paragraph 1. (Section 3) A receiver unit that measures the quality of the wireless link, A control unit starts a timer to determine whether a wireless link failure has occurred when the number of times a wireless link quality degradation notification has been detected within the number of times a wireless link quality normal notification has been detected, or within a certain time period, reaches a threshold. A terminal equipped with the following features. (Section 4) If the monitored cell is a cell that requires LBT, the control unit, upon detecting a failure in LBT, will use a value greater than a predetermined value as the threshold. The terminal described in paragraph 3. (Section 5) A transmitting unit that, when the number of consecutive detections of wireless link quality degradation notifications reaches a first threshold, starts a timer and sends a reference signal to a terminal that determines whether the number of consecutive occurrences of wireless link quality normal notifications has reached a second threshold before the timer expires. The first threshold or the second threshold is a value greater than a predetermined value, and the transmitting unit transmits the first threshold or the second threshold to the terminal. Base station equipment. (Section 6) A transmitting unit that transmits a reference signal to a terminal that starts a timer to determine whether or not a wireless link failure has occurred when the number of times a wireless link quality degradation notification has been detected within a certain number of times a wireless link quality normal notification has been detected, or within a certain time period, reaches a threshold; The transmitting unit transmits the threshold, the number of times, or the duration to the terminal. Base station.

[0260] <Configuration of Examples 2 and 3> (Section 1) A receiver that monitors the quality of the beam, The system includes a control unit that initiates a beam failure recovery procedure if, after the timer is started and before the timer expires, the number of times quality degradation of all beams in a given set is detected exceeds a threshold, The threshold is a value greater than a predetermined value. Terminal. (Section 2) The control unit determines the timer duration based on a duration less than 2 msec. The terminal described in paragraph 1. (Section 3) If the carrier frequency or SCS in the monitored cell is greater than a predetermined value, the control unit uses a value greater than the predetermined value as the threshold. The terminal described in paragraph 1 or 2. (Section 4) When the monitored cell is one that requires LBT, the receiving unit monitors the beam quality by measuring a reference signal transmitted aperiodically from the base station equipment. A terminal as described in any one of paragraphs 1 through 3. (Section 5) The system includes a transmitting unit that transmits a reference signal to a terminal that initiates a beam fault recovery procedure if the number of times quality degradation of all beams in a given set is detected after the timer is started but before the timer expires exceeds a threshold. The threshold value is greater than a predetermined value, and the transmission unit transmits the threshold value to the terminal. Base station equipment. (Section 6) Steps to monitor beam quality, The procedure includes the step of starting a beam failure recovery procedure if, after starting the timer and before the timer expires, the number of times quality degradation of all beams in a given set has been detected exceeds a threshold, The threshold value is a value greater than a predetermined value A beam failure recovery method executed by a terminal

[0261] <Configuration related to Examples 4, 5, and 6> (Item 1) In a beam failure recovery procedure, a transmission unit that transmits a PRACH, a reception unit that starts monitoring a PDCCH when a certain number of slots have elapsed after transmitting the PRACH, and the number of slots is a value greater than a predetermined value Terminal (Item 2) The reception unit uses, as the number of slots, a value obtained by adding an offset to the predetermined value The terminal according to Item 1 (Item 3) In a beam failure recovery procedure, a transmission unit that reports a new beam detected by beam search to a base station device, a reception unit that receives a beam failure recovery response after reporting the new beam, and a control unit that performs QCL update based on the new beam after a certain number of symbols have elapsed after receiving the beam failure recovery response, and the number of symbols is a value greater than a predetermined value or a value smaller than a predetermined value Terminal (Item 4) The control unit uses, as the number of symbols, a value obtained by adding an offset to the predetermined value The terminal according to Item 3 (Item 5) The number of candidate beams to be searched by beam search in the beam recovery procedure is greater than a predetermined value, or the number of beams to be monitored for detecting a trigger of the beam failure recovery procedure is greater than a predetermined value The terminal according to any one of Items 1 to 4 (Item 6) In the beam failure recovery procedure, the receiving unit receives PRACH, The system includes a transmitting unit that transmits a PDCCH after a certain number of slots of time have elapsed since receiving the PRACH, The number of slots is greater than a predetermined value. Base station equipment. (Section 7) In the beam failure recovery procedure, the step of sending PRACH, The system includes the step of starting to monitor PDCCH after a certain number of slots have elapsed since the transmission of PRACH. The number of slots is greater than a predetermined value. The beam failure recovery method performed by the terminal.

[0262] <Configuration of Examples 7 and 8> (Section 1) A receiving unit that receives signals using the same beam across multiple component carriers, A control unit that updates the QCL in the plurality of component carriers based on a new beam selected by a beam failure recovery procedure in one of the plurality of component carriers, and A terminal equipped with the following features. (Section 2) The aforementioned plurality of component carriers are component carriers set by the base station equipment, or component carriers whose carrier frequency is greater than a certain value. The terminal described in paragraph 1. (Section 3) The control unit performs a beam search in the beam fault recovery procedure, measuring candidate beams in the plurality of component carriers. The terminal described in paragraph 1 or 2. (Section 4) In the beam failure recovery procedure, a receiving unit selects multiple beams by performing a beam search, A transmitting unit that reports the selected plurality of beams to the base station equipment via PRACH or MAC CE, A terminal equipped with the following features. (Section 5) A transmitting unit that transmits signals using the same beam across multiple component carriers, A control unit that updates the beams in the plurality of component carriers based on a new beam selected by a beam failure recovery procedure in one of the plurality of component carriers. A base station device equipped with the following features. (Section 6) The steps include receiving signals using the same beam across multiple component carriers, A step of updating the QCL in the plurality of component carriers based on a new beam selected by a beam failure recovery procedure in one of the plurality of component carriers. A beam fault recovery method performed by a terminal, comprising the above.

[0263] Any of the above configurations provides a technology that enables a terminal in a wireless communication system to properly detect and recover from high-frequency communication failures.

[0264] (Hardware configuration) The block diagrams (Figures 17 and 18) used in the description of the above embodiments show functional units. These functional blocks (components) are realized by any combination of at least one of hardware and software. Furthermore, the method of realizing each functional block is not particularly limited. That is, each functional block may be realized using one device that is physically or logically coupled, or it may be realized using two or more physically or logically separated devices that are directly or indirectly connected (for example, using wired or wireless connections). A functional block may be realized by combining the one or more devices with software.

[0265] Functions include, but are not limited to, judgment, decision, judgment, calculation, calculation, processing, derivation, investigation, exploration, confirmation, reception, transmission, output, access, resolution, selection, selection, establishment, comparison, assumption, expectation, assumption, broadcasting, notifying, communicating, forwarding, configuring, reconfiguring, allocating (mapping), and assigning. For example, a functional block (configuration part) that enables transmission is called a transmitting unit or transmitter. As mentioned above, the method of implementation is not particularly limited.

[0266] For example, the base station device 10, terminal 20, etc. in one embodiment of the present disclosure may function as a computer that processes the wireless communication method of the present disclosure. Figure 19 is a diagram showing an example of the hardware configuration of the base station device 10 and terminal 20 according to one embodiment of the present disclosure. The above-mentioned base station device 10 and terminal 20 may be physically configured as a computer device including a processor 1001, a storage device 1002, an auxiliary storage device 1003, a communication device 1004, an input device 1005, an output device 1006, a bus 1007, etc.

[0267] In the following explanation, the term "device" can be read as "circuit," "device," "unit," etc. The hardware configuration of the base station device 10 and the terminal 20 may include one or more of the devices shown in the figure, or it may be configured to omit some of the devices.

[0268] Each function in the base station device 10 and terminal 20 is realized by loading predetermined software (programs) onto hardware such as the processor 1001 and storage device 1002, which allows the processor 1001 to perform calculations, control communication by the communication device 1004, and control at least one of the reading and writing of data in the storage device 1002 and auxiliary storage device 1003.

[0269] The processor 1001 controls the entire computer, for example, by running an operating system. The processor 1001 may consist of a central processing unit (CPU) that includes interfaces with peripheral devices, control devices, arithmetic units, registers, etc. For example, the control unit 140, control unit 240, etc., described above may be implemented by the processor 1001.

[0270] Furthermore, the processor 1001 reads programs (program code), software modules, or data from at least one of the auxiliary storage device 1003 and the communication device 1004 into the storage device 1002, and executes various processes accordingly. The program used is one that causes a computer to execute at least a part of the operations described in the above embodiment. For example, the control unit 140 of the base station device 10 shown in Figure 17 may be implemented by a control program stored in the storage device 1002 and operated by the processor 1001. Also, for example, the control unit 240 of the terminal 20 shown in Figure 18 may be implemented by a control program stored in the storage device 1002 and operated by the processor 1001. Although the above processes have been described as being executed by one processor 1001, they may be executed simultaneously or sequentially by two or more processors 1001. The processor 1001 may be implemented by one or more chips. The program may be transmitted from the network via a telecommunications line.

[0271] The storage device 1002 is a computer-readable recording medium and may consist of at least one of the following: ROM (Read Only Memory), EPROM (Erasable Programmable ROM), EEPROM (Electrically Erasable Programmable ROM), RAM (Random Access Memory), etc. The storage device 1002 may also be called a register, cache, main memory, etc. The storage device 1002 can store executable programs (program code), software modules, etc., for implementing a communication method according to one embodiment of this disclosure.

[0272] The auxiliary storage device 1003 is a computer-readable recording medium and may consist of at least one of the following: an optical disc such as a CD-ROM (Compact Disc ROM), a hard disk drive, a flexible disk, a magneto-optical disk (e.g., a compact disc, a digital multipurpose disc, a Blu-ray® disc), a smart card, flash memory (e.g., a card, a stick, a key drive), a floppy® disk, a magnetic strip, etc. The above-mentioned storage medium may also be a database, server, or other suitable medium that includes at least one of the storage device 1002 and the auxiliary storage device 1003.

[0273] The communication device 1004 is hardware (transmitting / receiving device) for communicating between computers via at least one of a wired network and a wireless network, and is also referred to as a network device, network controller, network card, communication module, etc. The communication device 1004 may be configured to include high-frequency switches, duplexers, filters, frequency synthesizers, etc., in order to implement at least one of frequency division duplex (FDD) and time division duplex (TDD). For example, the transmitting and receiving antennas, amplifier section, transmitting and receiving section, transmission path interface, etc., may be implemented by the communication device 1004. The transmitting and receiving section may be implemented in a physically or logically separated manner, with a transmitting section and a receiving section.

[0274] The input device 1005 is an input device that accepts input from an external source (e.g., a keyboard, mouse, microphone, switch, button, sensor, etc.). The output device 1006 is an output device that outputs to an external source (e.g., a display, speaker, LED lamp, etc.). The input device 1005 and the output device 1006 may be configured as an integrated unit (e.g., a touch panel).

[0275] Furthermore, each device, such as the processor 1001 and the storage device 1002, is connected by a bus 1007 for communicating information. The bus 1007 may be configured using a single bus, or different buses may be configured for each device.

[0276] Furthermore, the base station equipment 10 and the terminal 20 may be configured to include hardware such as a microprocessor, a digital signal processor (DSP), an ASIC (Application Specific Integrated Circuit), a PLD (Programmable Logic Device), and an FPGA (Field Programmable Gate Array), and some or all of each functional block may be realized by such hardware. For example, the processor 1001 may be implemented using at least one of these hardware components.

[0277] (Supplement to the embodiment) While embodiments of the present invention have been described above, the disclosed invention is not limited to such embodiments, and those skilled in the art will understand various modifications, alterations, alternatives, substitutions, etc. Specific numerical examples have been used to facilitate understanding of the invention, but unless otherwise specified, these numerical values ​​are merely examples, and any appropriate values ​​may be used. The division of items in the above description is not essential to the present invention, and matters described in two or more items may be combined as needed, and matters described in one item may be applied to matters described in another item (as long as they do not contradict each other). The boundaries of functional units or processing units in the functional block diagram do not necessarily correspond to the boundaries of physical parts. The operation of multiple functional units may be physically performed by one part, or the operation of one functional unit may be physically performed by multiple parts. Regarding the processing procedures described in the embodiments, the order of processing may be changed as long as it does not contradict each other. For the convenience of explaining the processing, the base station device 10 and terminal 20 have been described using functional block diagrams, but such devices may be implemented in hardware, software, or a combination thereof. The software operated by the processor of the base station device 10 according to an embodiment of the present invention and the software operated by the processor of the terminal 20 according to an embodiment of the present invention may be stored in random access memory (RAM), flash memory, read-only memory (ROM), EPROM, EEPROM, registers, hard disk (HDD), removable disk, CD-ROM, database, server, or any other suitable storage medium.

[0278] Furthermore, the notification of information is not limited to the embodiments / models described herein and may be carried out by other methods. For example, the notification of information may be carried out by physical layer signaling (e.g., DCI (Downlink Control Information), UCI (Uplink Control Information)), upper layer signaling (e.g., RRC (Radio Resource Control) signaling, MAC (Medium Access Control) signaling, broadcast information (MIB (Master Information Block), SIB (System Information Block))), other signals, or combinations thereof. Also, RRC signaling may be called RRC messages, and may be, for example, RRC Connection Setup messages, RRC Connection Reconfiguration messages, etc.

[0279] Each aspect / embodiment described in this disclosure may be applied to at least one of the following systems: LTE (Long Term Evolution), LTE-A (LTE-Advanced), SUPER 3G, IMT-Advanced, 4G (4th generation mobile communication system), 5G (5th generation mobile communication system), FRA (Future Radio Access), NR (new Radio), W-CDMA (registered trademark), GSM (registered trademark), CDMA2000, UMB (Ultra Mobile Broadband), IEEE 802.11 (Wi-Fi (registered trademark)), IEEE 802.16 (WiMAX (registered trademark)), IEEE 802.20, UWB (Ultra-WideBand), Bluetooth (registered trademark), and other appropriate systems, as well as next-generation systems extended based thereon. Furthermore, multiple systems may be applied in combination (for example, a combination of at least one of LTE and LTE-A with 5G).

[0280] The processing procedures, sequences, flowcharts, etc., of each aspect / embodiment described herein may be reordered, provided they are consistent with each other. For example, the methods described herein present various step elements in an exemplary order and are not limited to that specific order.

[0281] In this specification, specific operations performed by the base station device 10 may, in some cases, be performed by its upper node. In a network consisting of one or more network nodes having a base station device 10, it is clear that various operations performed for communication with the terminal 20 can be performed by the base station device 10 and at least one of the other network nodes (for example, an MME or S-GW, but not limited to these). Although the above example illustrates the case where there is one other network node besides the base station device 10, the other network node may be a combination of multiple other network nodes (for example, an MME and an S-GW).

[0282] The information or signals described in this disclosure may be output from a higher layer (or lower layer) to a lower layer (or higher layer). They may also be input and output via multiple network nodes.

[0283] Input and output information may be stored in a specific location (e.g., memory) or managed using a management table. Input and output information may be overwritten, updated, or appended to. Output information may be deleted. Input information may be transmitted to other devices.

[0284] The determination in this disclosure may be made by a value represented by one bit (0 or 1), by a boolean value (true or false), or by a numerical comparison (for example, a comparison with a predetermined value).

[0285] Software should be broadly interpreted to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software modules, applications, software applications, software packages, routines, subroutines, objects, executable files, execution threads, procedures, functions, and so on, whether they are called software, firmware, middleware, microcode, hardware description languages, or by any other name.

[0286] Furthermore, software, instructions, information, etc., may be transmitted and received via a transmission medium. For example, if software is transmitted from a website, server, or other remote source using at least one of wired technology (such as coaxial cable, fiber optic cable, twisted pair, or digital subscriber line (DSL)) and wireless technology (such as infrared or microwave), then at least one of these wired and wireless technologies is included in the definition of a transmission medium.

[0287] The information, signals, etc. described in this disclosure may be represented using any of the various different techniques. For example, the data, instructions, commands, information, signals, bits, symbols, chips, etc. that may be referred to throughout the above description may be represented by voltage, current, electromagnetic waves, magnetic fields or magnetic particles, optical fields or photons, or any combination thereof.

[0288] In addition, terms used in this disclosure and terms necessary for understanding this disclosure may be replaced with terms having the same or similar meanings. For example, at least one of the channel and symbol may be a signal (signaling). Also, a signal may be a message. Furthermore, a component carrier (CC) may be called a carrier frequency, cell, frequency carrier, etc.

[0289] The terms “system” and “network” as used in this disclosure are interchangeable.

[0290] Furthermore, the information, parameters, etc., described in this disclosure may be expressed using absolute values, relative values ​​from a given value, or corresponding other information. For example, wireless resources may be indicated by an index.

[0291] The names used for the parameters described above are not restrictive in any way. Furthermore, the formulas and other expressions using these parameters may differ from those expressly disclosed in this disclosure. Various channels (e.g., PUCCH, PDCCH, etc.) and information elements can be identified by any suitable name, and therefore, the various names assigned to these various channels and information elements are not restrictive in any way.

[0292] In this disclosure, terms such as "base station (BS)", "wireless base station", "base station equipment", "fixed station", "NodeB", "eNodeB (eNB)", "gNodeB (gNB)", "access point", "transmission point", "reception point", "transmission / reception point", "cell", "sector", "cell group", "carrier", and "component carrier" may be used interchangeably. Base stations may also be referred to by terms such as macrocell, small cell, femtocell, and picocell.

[0293] A base station can accommodate one or more (e.g., three) cells. If a base station accommodates multiple cells, the entire coverage area of ​​the base station can be divided into several smaller areas, each of which may also be provided with communication services by a base station subsystem (e.g., a Remote Radio Head (RRH)). The terms “cell” or “sector” refer to part or all of the coverage area of ​​at least one of the base station and / or base station subsystems that provide communication services in that coverage.

[0294] In this disclosure, terms such as "Mobile Station (MS)," "user terminal," "User Equipment (UE)," and "terminal" may be used interchangeably.

[0295] A mobile station may also be referred to by those skilled in the art as a subscriber station, mobile unit, subscriber unit, wireless unit, remote unit, mobile device, wireless device, wireless communication device, remote device, mobile subscriber station, access terminal, mobile terminal, wireless terminal, remote terminal, handset, user agent, mobile client, client, or several other appropriate terms.

[0296] At least one of the base station and the mobile station may be called a transmitting device, a receiving device, a communication device, etc. At least one of the base station and the mobile station may be a device mounted on a mobile body, the mobile body itself, etc. The mobile body may be a vehicle (e.g., a car, an airplane, etc.), an unmanned mobile body (e.g., a drone, an autonomous vehicle, etc.), or a robot (manned or unmanned). At least one of the base station and the mobile station may be a device that does not necessarily move during communication operation. For example, at least one of the base station and the mobile station may be an IoT (Internet of Things) device such as a sensor.

[0297] Furthermore, the term "base station" in this disclosure may be interpreted as "terminal." For example, the various aspects / embodiments of this disclosure may be applied to a configuration in which communication between a base station and a terminal is replaced with communication between multiple terminals 20 (which may be called, for example, D2D (Device-to-Device), V2X (Vehicle-to-Everything)). In this case, the terminals 20 may have the functions that the base station device 10 has. Also, terms such as "uplink" and "downlink" may be interpreted as terms corresponding to terminal-to-terminal communication (for example, "side"). For example, uplink channel, downlink channel, etc., may be interpreted as side channel.

[0298] Similarly, the term "terminal" in this disclosure may be replaced with "base station." In this case, the base station may be configured to have the same functions as the terminal described above.

[0299] As used in this disclosure, the terms “determining” and “determining” may encompass a wide variety of actions. “Determining” may include, for example, judging, calculating, computing, processing, deriving, investigating, looking up, searching, inquiry (e.g., searching in a table, database, or other data structure), and ascertaining. “Determining” may also include, for example, receiving (e.g., receiving information), transmitting (e.g., sending information), input, output, and accessing (e.g., accessing data in memory). Furthermore, "judgment" and "decision" can include considering something as having been "judged" or "decided" after resolving, selecting, choosing, establishing, comparing, etc. In other words, "judgment" and "decision" can include considering something as having been "judged" or "decided" after some action. Also, "judgment (decision)" can be reinterpreted as "assuming," "expecting," or "considering."

[0300] The terms “connected,” “coupled,” or any variation thereof, mean any direct or indirect connection or coupling between two or more elements, and may include the presence of one or more intermediate elements between two elements that are “connected” or “coupled” with each other. The coupling or connection between elements may be physical, logical, or a combination thereof. For example, “connection” may be reinterpreted as “access.” As used in this disclosure, two elements may be considered to be “connected” or “coupled” with each other using at least one of one or more wires, cables, and printed electrical connections, and, in some non-limiting and non-exclusive examples, electromagnetic energy having wavelengths in the radio frequency domain, microwave domain, and optical (both visible and invisible) domain.

[0301] The reference signal can also be abbreviated as RS (Reference Signal), and may be called a pilot depending on the applicable standard.

[0302] In this disclosure, the phrase "based on" does not mean "based solely on" unless otherwise specified. In other words, the phrase "based on" means both "based solely on" and "based at least on."

[0303] Any reference to elements using the designations “first,” “second,” etc., as used in this disclosure does not generally limit the quantity or order of those elements. These designations may be used in this disclosure as a convenient way to distinguish between two or more elements. Accordingly, references to the first and second elements do not imply that only two elements may be employed, or that the first element must precede the second element in any way.

[0304] In the configuration of each of the above devices, "means" may be replaced with "part," "circuit," "device," etc.

[0305] Where the terms “include,” “including,” and variations thereof are used in this disclosure, these terms are intended to be inclusive, as is the term “comprising.” Furthermore, the term “or” as used in this disclosure is not intended to mean exclusive OR.

[0306] A wireless frame may consist of one or more frames in the time domain. Each of these frames in the time domain may be called a subframe. A subframe may further consist of one or more slots in the time domain. A subframe may have a fixed time length (e.g., 1 ms) that is independent of numerology.

[0307] Numerical logic may be communication parameters applied to at least one of the transmission and reception of a signal or channel. Numerical logic may include, for example, at least one of the following: subcarrier spacing (SCS), bandwidth, symbol length, cyclic prefix length, transmission time interval (TTI), number of symbols per TTI, radio frame configuration, specific filtering processes performed by the transceiver in the frequency domain, and specific windowing processes performed by the transceiver in the time domain.

[0308] A slot may consist of one or more symbols in the time domain (such as OFDM (Orthogonal Frequency Division Multiplexing) symbols, SC-FDMA (Single Carrier Frequency Division Multiple Access) symbols, etc.). A slot may also be a time unit based on neurology.

[0309] A slot may include multiple minislots. Each minislot may consist of one or more symbols in the time domain. Minislots may also be called subslots. Minislots may consist of fewer symbols than a slot. A PDSCH (or PUSCH) transmitted in a time unit larger than a minislot may be called PDSCH (or PUSCH) mapping type A. A PDSCH (or PUSCH) transmitted using a minislot may be called PDSCH (or PUSCH) mapping type B.

[0310] Wireless frames, subframes, slots, minislots, and symbols all represent units of time when transmitting a signal. Different names may be used for each of these terms.

[0311] For example, one subframe may be called a Transmission Time Interval (TTI), multiple consecutive subframes may be called a TTI, or one slot or one mini-slot may be called a TTI. In other words, at least one of a subframe and a TTI may be a subframe (1 ms) in existing LTE, a period shorter than 1 ms (e.g., 1-13 symbols), or a period longer than 1 ms. Note that the unit representing the TTI may be called a slot, mini-slot, etc., instead of a subframe. Also, one slot may be called a unit time. The unit time may differ from cell to cell depending on the neurology.

[0312] Here, TTI refers to, for example, the smallest unit of time for scheduling in wireless communication. For example, in an LTE system, the base station schedules each terminal 20 to allocate wireless resources (such as the frequency bandwidth and transmission power available to each terminal 20) in TTI units. However, the definition of TTI is not limited to this.

[0313] TTI may be a transmission time unit for channel-encoded data packets (transport blocks), code blocks, code words, etc., or it may be a processing unit for scheduling, link adaptation, etc. Given a TTI, the actual time interval (e.g., number of symbols) to which the transport block, code block, code word, etc. are mapped may be shorter than the given TTI.

[0314] Furthermore, if one slot or one mini-slot is referred to as TTI, then one or more TTIs (i.e., one or more slots or one or more mini-slots) may constitute the minimum time unit of scheduling. In addition, the number of slots (number of mini-slots) that constitute the minimum time unit of scheduling may be controlled.

[0315] A TTI with a time length of 1ms may also be called a normal TTI, long TTI, normal subframe, long subframe, slot, etc. A TTI shorter than a normal TTI may also be called a shortened TTI, short TTI, partial or fractional TTI, shortened subframe, short subframe, mini slot, sub slot, slot, etc.

[0316] Furthermore, long TTIs (e.g., normal TTIs, subframes, etc.) may be interpreted as TTIs with a time length exceeding 1 ms, and short TTIs (e.g., shortened TTIs, etc.) may be interpreted as TTIs with a TTI length less than that of a long TTI but 1 ms or more.

[0317] A resource block (RB) is a resource allocation unit in the time domain and frequency domain, and in the frequency domain, it may contain one or more consecutive subcarriers. The number of subcarriers in an RB may be the same regardless of the neurology, for example, 12. The number of subcarriers in an RB may be determined based on the neurology.

[0318] Furthermore, the time domain of RB may contain one or more symbols and may be the length of one slot, one minislot, one subframe, or one TTI. One TTI, one subframe, etc., may each consist of one or more resource blocks.

[0319] One or more RBs may also be called a Physical RB (PRB), Sub-Carrier Group (SCG), Resource Element Group (REG), PRB pair, RB pair, etc.

[0320] Furthermore, a resource block may consist of one or more resource elements (REs). For example, one RE may be a radio resource area comprising one subcarrier and one symbol.

[0321] A Bandwidth Part (BWP), also known as a partial bandwidth, may represent a subset of consecutive common resource blocks (RBs) for a particular neurology system in a given carrier. These common RBs may be identified by an index of the RBs relative to a common reference point of the carrier. A Bandwidth Part (PRB) may be defined and numbered within a given BWP.

[0322] A BWP may include BWPs for UL (UL BWP) and BWPs for DL ​​(DL BWP). One or more BWPs may be configured within a single carrier for a UE.

[0323] At least one of the configured BWPs may be active, and the UE does not need to assume that it will send or receive a given signal / channel outside of the active BWP. In this disclosure, terms such as "cell" and "carrier" may be read as "BWP".

[0324] The structures described above, such as wireless frames, subframes, slots, minislots, and symbols, are merely illustrative. For example, the number of subframes included in a wireless frame, the number of slots per subframe or wireless frame, the number of minislots included in a slot, the number of symbols and RBs included in a slot or minislot, the number of subcarriers included in an RB, and the number of symbols, symbol length, and cyclic prefix (CP) length within a TTI can be varied in various ways.

[0325] In this disclosure, if articles are added through translation, such as a, an, and the in English, this disclosure may include the fact that the noun following these articles is plural.

[0326] In this disclosure, the term "A and B are different" may mean "A and B are different from each other." The term may also mean "A and B are each different from C." Terms such as "separate" and "combine" may be interpreted similarly to "different."

[0327] Each aspect / embodiment described herein may be used individually, in combination, or switched between as needed during implementation. Furthermore, notification of specific information (e.g., notification that "X is") is not limited to explicit notification, but may also be implicit (e.g., by not providing such notification).

[0328] Although the present disclosure has been described in detail above, it will be clear to those skilled in the art that the present disclosure is not limited to the embodiments described herein. The present disclosure can be implemented in modified and altered forms without departing from the intent and scope of the present disclosure as defined by the claims. Therefore, the descriptions in the present disclosure are illustrative and not intended to be restrictive in any way. [Explanation of Symbols]

[0329] 10 Base station equipment 110 Transmitter 120 Receiver 130 Setting section 140 Control Unit 20 devices 210 Transmitter 220 Receiver 230 Setting section 240 Control Unit 1001 Processor 1002 Storage device 1003 Auxiliary storage device 1004 Communication device 1005 Input device 1006 Output device

Claims

1. A receiver that monitors the quality of the beam, A control unit that initiates a beam failure recovery procedure if, after starting the timer and before the timer expires, the number of times it has detected quality degradation in all beams in a given set meets a predetermined condition, A terminal equipped with the following features.

2. The control unit determines the timer duration based on a duration less than 2 msec. The terminal according to claim 1.

3. When the monitored cell is one that requires LBT, the receiving unit monitors the beam quality by measuring a reference signal transmitted aperiodically from the base station equipment. The terminal according to claim 1 or 2.

4. Steps to monitor beam quality, The procedure includes the step of starting a beam failure recovery procedure if, after starting a timer and before the timer expires, the number of times a quality degradation of all beams in a given set has been detected satisfies a predetermined condition. The beam failure recovery method performed by the terminal.

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