Terminal, wireless communication method, and base station

Abstract

A terminal according to one embodiment of the present disclosure is characterized by being provided with: a control unit that measures a synchronization signal block (SSB) corresponding to a set of a plurality of beams per layer, and determines an index for an optimal beam on the basis of the measurement results; and a transmission unit which transmits a physical random access channel (PRACH) which corresponds to the index of the optimal beam, and which transmits a physical random access channel (PRACH) which corresponds to the index of the optimal beam. According to one embodiment of the present disclosure, it is possible to quickly determine an optimal beam.

Description

Technical Field

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

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

[0003] Successor systems to LTE (also known as, for example, fifth-generation mobile communication system (5G), 5G+ (plus), sixth-generation mobile communication system (6G), New Radio (NR), and 3GPP Rel. 15 and later) are also under study.

[0004] Prior art literature

[0005] Non-patent literature

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

[0007] Problems to be solved by the invention

[0008] In future wireless communication systems (e.g., NR), research is underway to enable terminals (user terminals, User Equipment (UE)) to use multiple beams to receive multiple synchronization signal (SSB) signals per SSB transmission period. Each SSB has multiple SSB indices. A UE that detects an SSB transmits a physical random access channel (PRACH) in the random access channel (RACH) opportunity associated with that SSB index.

[0009] However, when the number of beams is large, the number of transmitted SSBs also increases, so there is a concern that the UE's SSB measurement and optimal beam determination will take a long time. As a result, there is a concern that initial access will take a long time and communication throughput will decrease.

[0010] Therefore, one of the objects of the present disclosure is to provide a terminal, a wireless communication method, and a base station that can quickly determine an optimal beam.

[0011] Means for solving problems

[0012] A terminal involved in one embodiment of the present disclosure is characterized in that it has: a control unit that measures a synchronization signal block (SSB) corresponding to a set of multiple beams in each layer, and determines the index of the optimal beam based on the measurement result; and a transmitting unit that transmits a physical random access channel (PRACH) corresponding to the index of the optimal beam.

[0013] Effects of the Invention

[0014] According to one aspect of the present disclosure, it is possible to quickly determine the optimal beam. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1A This is a diagram showing an example of a beam detection method in existing NR. Figure 1B This is a diagram showing an example of a beam detection method in multiple stages. Figure 1C It is a diagram showing an example of beam detection in the first embodiment.

[0016] Figure 2 This is a diagram showing an example of expressing beam detection in this embodiment in binary.

[0017] Figure 3 This is a diagram showing a first example of beam detection in this embodiment.

[0018] Figure 4 This is a diagram showing a second example of beam detection in this embodiment.

[0019] Figure 5 This is a diagram showing another example of mapping of SSB indexes in each layer.

[0020] Figure 6 This diagram shows an example of mapping beams and SSBs when some beams are not used.

[0021] Figure 7 This is a diagram showing a comparison of the number of SSBs between the conventional NR and the first embodiment (proposal).

[0022] Figure 8 It is a diagram showing the SSB detection period in an embodiment.

[0023] Figure 9 This is a diagram showing an example of a processing procedure between a terminal and a base station in Example 2-1.

[0024] Figure 10 This is a diagram showing an example of a processing procedure between a terminal and a base station in Example 2-2.

[0025] Figure 11 This is a diagram showing an example of a processing procedure between a terminal and a base station in Example 2-3.

[0026] Figure 12 This is a diagram showing an example of processing in method 3-1.

[0027] Figure 13 This is a diagram showing an example of processing in method 3-2.

[0028] Figure 14 This is a diagram showing an example of a schematic configuration of a wireless communication system according to one embodiment.

[0029] Figure 15 This is a diagram showing an example of the configuration of a base station according to one embodiment.

[0030] Figure 16 This is a diagram showing an example of the configuration of a user terminal according to one embodiment.

[0031] Figure 17 This is a diagram showing an example of the hardware configuration of a base station and a user terminal according to one embodiment.

[0032] Figure 18 This is a diagram showing an example of a vehicle according to an embodiment. DETAILED DESCRIPTION

[0033] (TCI, spatial relation, QCL)

[0034] In NR, research is underway to control the reception processing (e.g., at least one of reception, demapping, demodulation, and decoding) and transmission processing (e.g., at least one of transmission, mapping, precoding, modulation, and coding) of at least one of a signal and a channel (expressed as signal / channel) in the UE based on the Transmission Configuration Indication state (TCI state).

[0035] The TCI state may also indicate the state of a signal / channel applied to a downlink. A state equivalent to the TCI state applied to a signal / channel applied to an uplink may also be expressed as a spatial relation.

[0036] The TCI status is information related to Quasi-Co-Location (QCL) of signals / channels and may also be referred to as spatial reception parameters, spatial relation information, etc. The TCI status may be set for each channel or each signal for the UE.

[0037] QCL is an indicator of the statistical properties of a signal / channel. For example, it can mean that when a signal / channel is in a QCL relationship with other signals / channels, it can be assumed that at least one of the Doppler shift, Doppler spread, average delay, delay spread, and spatial parameters (e.g., spatial Rx parameters) is the same among these different signals / channels (at least one of which is QCL).

[0038] In addition, the spatial reception parameter may also correspond to the UE's receive beam (eg, receive analog beam), and the beam may also be determined based on spatial QCL. The QCL (or at least one element of QCL) in this disclosure may also be rewritten as sQCL (spatial QCL).

[0039] Multiple QCL types (QCL types) can be specified. For example, four QCL types AD can be provided. The parameters (or parameter sets) that can be assumed to be the same in these four QCL types AD are different. These parameters (also referred to as QCL parameters) are expressed as follows:

[0040] QCL Type A (QCL-A): Doppler shift, Doppler spread, average delay, and delay spread;

[0041] QCL type B (QCL-B): Doppler shift and Doppler spread;

[0042] QCL type C (QCL-C): Doppler shift and average delay;

[0043] QCL type D (QCL-D): spatial reception parameters.

[0044] The UE assumes that a certain Control Resource Set (CORESET), channel or reference signal is in a specific QCL relationship (e.g., QCL type D) with other CORESETs, channels or reference signals. This situation can also be called QCL assumption.

[0045] The UE may also determine at least one of a transmit beam (Tx beam) and a receive beam (Rx beam) of the signal / channel based on the TCI status or QCL assumption of the signal / channel.

[0046] The TCI status may also include, for example, information related to the QCL of the target channel (in other words, the reference signal (RS) used for that channel) and other signals (for example, other RSs). The TCI status may also be set (indicated) via higher-layer signaling, physical-layer signaling, or a combination thereof.

[0047] The physical layer signaling may be, for example, downlink control information (Downlink Control Information (DCI))).

[0048] The channel for which the TCI state or spatial relationship is set (specified) may be, for example, at least one of a downlink shared channel (Physical Downlink Shared Channel (PDSCH)), a downlink control channel (Physical Downlink Control Channel (PDCCH)), an uplink shared channel (Physical Uplink Shared Channel (PUSCH)), and an uplink control channel (Physical Uplink Control Channel (PUCCH)).

[0049] In addition, the RS that has a QCL relationship with the channel may be, for example, at least one of a synchronization signal block (Synchronization Signal Block (SSB)), a channel state information reference signal (Channel State Information Reference Signal (CSI-RS)), a measurement reference signal (Sounding Reference Signal (SRS)), a tracking CSI-RS (also called a tracking reference signal (TRS)), and a QCL detection reference signal (also called QRS).

[0050] The SSB is a signal block that includes at least one of a primary synchronization signal (PSS), a secondary synchronization signal (SSS), and a broadcast channel (physical broadcast channel (PBCH)). The SSB may also be referred to as an SS / PBCH block.

[0051] The RS of QCL type X in the TCI state may also mean an RS that is in a QCL type X relationship with a certain channel / signal (DMRS), and the RS may also be called a QCL source of QCL type X in the TCI state.

[0052] (Initial access process)

[0053] During the initial access process, the UE (RRC_IDLE mode) performs the following operations: receiving the SS / PBCH block (SSB), transmitting Msg1 (PRACH / random access preamble / preamble), receiving Msg2 (PDCCH, PDSCH containing the random access response (RAR)), transmitting Msg3 (PUSCH scheduled by the RAR UL grant), and receiving Msg4 (PDCCH, PDSCH containing the UE contention resolution identity). The UE then sends an ACK for Msg4 via the base station (network), establishing an RRC connection (RRC_CONNECTED mode).

[0054] SSB reception includes PSS detection, SSS detection, PBCH-DMRS detection, and PBCH reception. PSS detection detects a portion of the physical cell ID (PCI), detects (synchronizes) OFDM symbol timing, and (roughly) synchronizes with the frequency. SSS detection includes detecting the physical cell ID. PBCH-DMRS detection includes detecting (a portion of) the SSB index within a half radio frame (5ms). PBCH reception includes detecting the system frame number (SFN) and radio frame timing (SSB index), receiving configuration information for receiving the remaining minimum system information (RMSI, SIB1), and determining whether the UE can camp on the cell (carrier).

[0055] SSB has a 20-bit bandwidth and a 4-symbol time. The SSB transmission period can be set from {5, 10, 20, 40, 80, 160} ms. Within a half-frame, multiple SSB symbol positions are specified based on the frequency range (FR1, FR2).

[0056] The PBCH has a 56-bit payload. N repetitions of the PBCH are transmitted in an 80 ms period. N depends on the SSB transmission period.

[0057] System information consists of the MIB, RMSI (SIB1), and other system information (OSI) transmitted via the PBCH. The SIB1 includes RACH configuration and information used for RACH procedures. The time / frequency relationship between the SSB and the PDCCH monitoring resources for SIB1 is configured via the PBCH.

[0058] A base station using beam correspondence transmits multiple SSBs using multiple beams per SSB transmission period. Each SSB has multiple SSB indices. A UE that detects an SSB transmits a PRACH in the RACH opportunity associated with that SSB index and receives a RAR in the RAR window.

[0059] However, when the number of beams is large, the number of transmitted SSBs also increases, so there is a concern that the UE's SSB measurement and optimal beam determination will take a long time. As a result, there is a concern that initial access will take a long time and communication throughput will decrease.

[0060] Therefore, the inventors of the present invention have conceived of a terminal that can quickly perform the determination of the best beam.

[0061] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. The wireless communication methods according to the respective embodiments may be applied individually or in combination.

[0062] In the present disclosure, "A / B" and "at least one of A and B" may be replaced with each other. In addition, in the present disclosure, "A / B / C" may also mean "at least one of A, B, and C."

[0063] In the present disclosure, the words “notify,” “activate,” “deactivate,” “indicate,” “select,” “configure,” “update,” and “determine” may be used interchangeably. In the present disclosure, the words “support,” “control,” “controllable,” “operate,” and “operable” may also be used interchangeably.

[0064] In this disclosure, Radio Resource Control (RRC), RRC parameters, RRC messages, higher-layer parameters, fields, Information Elements (IEs), and settings may also be overwritten. In this disclosure, Medium Access Control (MAC) Control Elements (CEs), update commands, and activation / deactivation commands may also be overwritten.

[0065] In the present disclosure, the higher layer signaling may be, for example, Radio Resource Control (RRC) signaling, Medium Access Control (MAC) signaling, broadcast information, or any one or a combination thereof.

[0066] In the present disclosure, MAC signaling may include, for example, a MAC Control Element (MACCE) and a MAC Protocol Data Unit (PDU). Broadcast information may include, for example, a Master Information Block (MIB), a System Information Block (SIB), minimum system information (Remaining Minimum System Information (RMSI)), and other system information (Other System Information (OSI)).

[0067] In the present disclosure, the physical layer signaling may also be, for example, downlink control information (Downlink Control Information (DCI)), uplink control information (Uplink Control Information (UCI)), etc.

[0068] In the present disclosure, an index, an identifier (ID), an indicator, a resource ID, etc. may also be overwritten with each other. In the present disclosure, a sequence, a list, a set, a group, a group, a cluster, a subset, etc. may also be overwritten with each other.

[0069] In the present disclosure, panel, UE panel, panel group, beam, beam group, precoder, Uplink (UL) transmitting entity, Transmission / Reception Point (TRP)), base station, Spatial Relation Information (SRI)), spatial relationship, SRS Resource Indicator (SRI)), Control Resource Set (CORESET)), Physical Downlink Shared Channel (PDSCH)), Codeword (CW), Transport Block (TB), Reference Signal (RS), Antenna Port (e.g., Demodulation Reference Signal (DMRS) port), Antenna Port Group (e.g., DMRS Port Group), Group (e.g., Spatial Relation Group, Code Division Multiplexing (CDM) Group), Reference Signal Group, CORESET Group, Physical Uplink Control Channel (PDSCH) Channel (PUCCH)) group, PUCCH resource group), resources (e.g., reference signal resources, SRS resources), resource sets (e.g., reference signal resource sets), CORESET pool, downlink transmission configuration indication state (TCI state) (DL TCI state), uplink TCI state (UL TCI state), unified TCI state (unified TCI state), common TCI state (common TCI state), Quasi-Co-Location (QCL)), QCL assumptions, etc. can also be rewritten with each other.

[0070] Furthermore, the spatial relationship information identifier (ID) (TCI state ID) and spatial relationship information (TCI state) can also be overwritten. "Spatial relationship information" can also be overwritten with "a set of spatial relationship information," "one or more spatial relationship information," and so on. TCI state and TCI can also be overwritten with each other.

[0071] In the present disclosure, beams and beam indices can also be replaced with each other. In the present disclosure, SSBs and SSB indices can also be replaced with each other. In the present disclosure, SSBs / beams are sent at different times using time division multiplexing (TDM), but can also be sent at the same time using space division multiplexing (SDM) or frequency division multiplexing (FDM). In the present disclosure, SSBs are used as reference signals, but other reference signals (for example, channel state information reference signals (CSI-RS)) can also be used. In other words, SSBs can also be replaced with CSI-RS, etc. In the present disclosure, RACH, PRACH, RACH preamble, and RA preamble can also be replaced with each other. In the present disclosure, RSRP and SINR can also be replaced with each other. In the present disclosure, layers, phases, stages, depths, etc. can also be replaced with each other.

[0072] (Wireless Communication Method)

[0073] <First embodiment>

[0074] The following describes a method for finding the optimal beam for both initial access and data transmission in a burst of SSBs using a small number of SSBs according to a detection algorithm. In this embodiment, the SSBs corresponding to the set of multiple beams per layer (e.g., Figure 1C 、 Figure 2 、 Figure 3 The UE determines the optimal beam index based on measurement results (e.g., Reference Signal Received Power (RSRP) or Signal to Interference plus Noise Ratio (SINR)). The UE then transmits (reports) the PRACH corresponding to the optimal beam index to the gNB.

[0075] Figure 1A This is a diagram showing an example of a beam detection method in conventional NR. Figure 1A In the example, each beam (narrow beam) corresponds to one SSB. The UE measures each SSB and determines the beam corresponding to the SSB with the highest RSRP as the best beam. Figure 1A In the example, the UE determines the beam corresponding to SSB index = 5 as the best beam.

[0076] Figure 1B is a diagram showing an example of a beam detection method in multiple stages. Figure 1BIn the example, 16 beams are divided into 4 wide beams. Each wide beam is a beam that combines 4 narrow beams. For beam refinement in connection mode, a specific RS (SSB) is set for the UE. In this example, each wide beam corresponds to one SSB. The UE measures each SSB and determines the wide beam corresponding to the SSB with the highest RSRP as the best beam. Figure 1B In the example, the UE determines the beam corresponding to SSB index = 1 as the optimal wide beam.

[0077] Figure 1C It is a diagram showing an example of beam detection in the first embodiment. Figure 1C An SSB index of 1 corresponds to the second beam when 16 beams are divided into two wide beams. An SSB index of 3 corresponds to the second and fourth beams when 16 beams are divided into four wide beams. An SSB index of 5 corresponds to the second, fourth, sixth, and eighth beams when 16 beams are divided into eight wide beams. An SSB index of 7 corresponds to the second, fourth, sixth, eighth, tenth, twelfth, fourteenth, and sixteenth beams of the 16 beams. That is, in the example of this embodiment, multiple wide beams / multiple narrow beams are transmitted simultaneously, and one SSB corresponds to the multiple wide beams / multiple narrow beams.

[0078] exist Figure 1C In the example, the wide beam corresponding to SSB index = 1 has a lower RSRP than other wide beams (the first beam when the 16 beams are divided into two wide beams) or the threshold. Furthermore, the wide beam corresponding to SSB index = 3 has a higher RSRP than other wide beams (the first and third beams when the 16 beams are divided into four wide beams) or the threshold. Furthermore, the wide beam corresponding to SSB index = 5 has a lower RSRP than other wide beams (the first, third, fifth, and seventh beams of the 16 beams) or the threshold. Furthermore, the wide beam corresponding to SSB index 7 has a higher RSRP than other wide beams (the first, third, fifth, seventh, ninth, eleventh, thirteenth, and fifteenth beams of the 16 beams) or the threshold.

[0079] Based on this result, the beam determined by the UE to be the best exists in the following beams: the first beam when the 16 beams are divided into 2 wide beams, the second and fourth beams when the 16 beams are divided into 4 wide beams, the first, third, fifth, and seventh beams when the 16 beams are divided into 8 wide beams, and the second, fourth, sixth, eighth, tenth, twelfth, fourteenth, and sixteenth beams of the 16 beams. Then, the UE determines that the sixth beam of the 16 beams is the best beam.

[0080] In addition, in the present disclosure, sometimes the case of transmitting both the SSB corresponding to the beam (narrow beam) of Figure 1A and the SSB corresponding to the wide beam / multiple beams of Figure 1C is described as hybrid SSB transmission.

[0081] Figure 2 is a diagram showing an example of beam detection in the present embodiment in binary representation. In the Figure 2 table, a 4-bit binary number corresponds to each beam (beam #0 to #15). In the first column, it is set to 0 when the RSRP of the wide beam corresponding to SSB#0 is large, and it is set to 1 when the RSRP of the wide beam corresponding to SSB#1 is large. In addition, "the RSRP of the beam is large" may also mean "the RSRP is greater than the RSRP of other beams" or "the RSRP is greater than the threshold value".

[0082] Similarly, in the second column, it is set to 0 when the RSRP of the wide beam corresponding to SSB#2 is large, and it is set to 1 when the RSRP of the wide beam corresponding to SSB#3 is large. In the third column, it is set to 0 when the RSRP of the wide beam corresponding to SSB#4 is large, and it is set to 1 when the RSRP of the wide beam corresponding to SSB#5 is large. In the fourth column, it is set to 0 when the RSRP of the beam corresponding to SSB#6 is large, and it is set to 1 when the RSRP of the beam corresponding to SSB#7 is large.

[0083] For example, when the RSRP of SSB#0 > the RSRP of SSB#1, the RSRP of SSB#2 > the RSRP of SSB#3, the RSRP of SSB#4 < the RSRP of SSB#5, and the RSRP of SSB#6 > the RSRP of SSB#7, the UE determines that the beam #2 corresponding to "0010" is the best beam.

[0084] For example, in the case where the RSRP of SSB#0 < the RSRP of SSB#1, the RSRP of SSB#2 > the RSRP of SSB#3, the RSRP of SSB#4 < the RSRP of SSB#5, and the RSRP of SSB#6 < the RSRP of SSB#7, the UE determines that beam#11 corresponding to "1011" is the best beam.

[0085] Figure 3 It is a diagram showing the first example of beam detection in this embodiment. Figure 3 The detection method of the example of Figure 1C , Figure 2 is the same as the example of Figure 1C and Figure 2 However, the order of assigning SSB indexes is partly different from the examples of Figure 3 shown. The UE compares the RSRP of SSBs in the same layer in each layer. In layer 1, the UE compares the RSRP of SSB#0 and #4. In layer 2, the UE compares the RSRP of SSB#1 and #5. In layer 3, the UE compares the RSRP of SSB#2 and #6. In layer 4, the UE compares the RSRP of SSB#3 and #7. Then, as Figure 3 shown, the UE obtains "0101" as the measurement result and determines beam#5 as the best beam according to the table of Figure 2 .

[0086] The UE can also send a random access preamble in the random access channel (RACH) resources corresponding to the SSBs with larger RSRP (SSB#1, #3, #4, #6) in each layer. The base station (gNB) assumes that all preambles are sent from one UE. Based on the random access preambles corresponding to the SSBs, the gNB can know that the UE has determined SSB#1, #3, #4, #6. Thus, the base station can determine beam#5 as the best beam.

[0087] Figure 4 It is a diagram showing the second example of beam detection in this embodiment. In the example of Figure 4 , it is different from the example of Figure 3 in that the RSRP of SSBs in each layer is compared with a threshold. The threshold is set to 10 dB. The UE compares the RSRP of SSBs in each layer with the threshold and determines that SSB#1 and #3 are greater than the threshold. The SSBs with RSRP above the threshold are set to 1, and the SSBs with RSRP below the threshold are set to 0, obtaining "0101" as the measurement result. Then, the UE determines beam#5 as the best beam according to the table of Figure 2 .

[0088] The threshold can also be, for example, a value obtained by subtracting a specific value from the maximum RSRP among the RSRPs of each layer (each SSB). In Figure 4In the example, the threshold value of 10dB is used, which is obtained by subtracting a specific value of 3dB from the maximum RSRP (13dB). The specific value can also be set or indicated to the UE via higher-layer signaling or physical layer signaling. Alternatively, instead of using the specific value, the threshold value can be set or indicated to the UE via higher-layer signaling or physical layer signaling.

[0089] The UE can also send random preambles in the RACH resources corresponding to SSB#1 and #3 with RSRP greater than the threshold in each layer. Figure 3 Similarly to the example, the base station (gNB) assumes that all preambles are transmitted from a single UE. Based on the random access preamble corresponding to each SSB, it can determine that the UE has selected SSBs #1 and #3. This allows the base station to select beam #5 as the optimal beam.

[0090] [Other examples of SSB mapping]

[0091] Figure 5 This is a diagram showing another example of mapping of SSB indexes in each layer. Figure 5 In the example, Figure 3 Different from the example, SSB#0 and #1 are mapped to the beam of layer 1, SSB#2 and #3 are mapped to the beam of layer 2, SSB#4 and #5 are mapped to the beam of layer 3, and SSB#6 and #7 are mapped to the beam of layer 4. Figure 3 The mapping can also be called depth-first mapping. Figure 5 The mapping can also be called width-first mapping.

[0092] [Adjustment of the number of beams]

[0093] The UE can also be configured / indicated by the gNB through higher layer signaling / physical layer signaling, such as the maximum number of beams supported. The UE can also receive M and K, or L and K. M is the total number of beams, L is the number of layers (depth / stage), and K is the number of beams in each layer (the number of beams measured). L is determined based on the number of beams corresponding to one SSB. For example, Figures 3-5 In the example, the layer with a beam number of 2 corresponding to 1 SSB is layer 1, the layer with a beam number of 4 corresponding to 1 SSB is layer 2, the layer with a beam number of 8 corresponding to 1 SSB is layer 3, and the layer with a beam number of 16 corresponding to 1 SSB is layer 4.

[0094] Option 1

[0095] Some of the beams (SSBs) in the multiple beams can also be muted. The UE cannot detect the muted SSBs and the corresponding beams, so the UE operation can also be the same as the existing method.

[0096] Option 2

[0097] The gNB can also map any beam index to an invalid beam. In this case, similar to Option 1, the UE operation can also be the same as the existing method.

[0098] Figure 6 This is a diagram showing an example of mapping beams and SSBs when some beams are not used. Figure 6 The example assumes that 16 narrow beams are associated with 4 SSBs. In Option 1, 4 of the 16 narrow beams are muted, resulting in 12 narrow beams associated with 3 SSBs. In Option 2, 12 narrow beams are associated with 4 SSBs, increasing the number of SSBs compared to Option 1, but reducing the number of beams associated with each SSB.

[0099] [Implementation results and effects]

[0100] As in the first embodiment, the base station (BS) transmits a synchronization signal block (SSB) using a predefined beam pattern, transmitting a logarithmically compressed beam index. The UE can detect the optimal beam index based on the received SSB sequence. For example, if the number of beams is M and the number of SSBs is N, then N = 2log2M.

[0101] Figure 7 This figure shows a comparison of the number of SSBs between the existing NR and the first embodiment (proposal). In the existing NR, the number of SSBs increases in accordance with the number of beams. In the first embodiment (proposal), as described above, N = 2log2M, so Figure 7 As shown in Figure 2, the number of SSBs can be suppressed compared to existing NRs. For example, even when transmitting 1024 beams, the gNB only transmits 20 SSBs. Figure 8 As shown, SSB can be sent in 5 ms of the 20 ms SSB period.

[0102] <Second embodiment>

[0103] In the second embodiment, the processing between the terminal (UE) and the base station (gNB) using the beam detection method of the first embodiment is specifically described. Furthermore, the new SSB in this embodiment represents the SSB corresponding to the wide beam / multiple narrow beams described in the first embodiment.

[0104] [Method 2-1]

[0105] Figure 9 This diagram illustrates an example of the processing between a terminal and a base station in Example 2-1. The base station (gNB) transmits a new SSB to the terminal (UE). Based on the received new SSB, the UE uses any of the methods described in the first embodiment to determine the optimal beam (beam index) and detect the path loss (PL) of the SSB and the path loss (PL) of the beam.

[0106] The UE then uses the determined beam (the PL of the determined beam) to transmit the PRACH corresponding to the determined beam (the SSB corresponding to the beam) to the gNB. This allows the gNB to know the optimal beam determined by the UE. The gNB then uses this optimal beam to send RRC signaling and other information to the UE.

[0107] According to this embodiment, the optimal beam is determined using the new SSB based on the first embodiment, and therefore the optimal beam can be determined efficiently with a small number of SSBs and measurements.

[0108] [Method 2-2]

[0109] Figure 10 This is a diagram showing an example of the processing procedure between the terminal and the base station in method 2-2. The base station (gNB) sends a new SSB to the terminal (UE). Based on the received new SSB, the UE uses any of the methods described in the first embodiment to determine the optimal beam (beam index) and the path loss (PL) of the SSB. At this point in time, the UE may not have correctly grasped the channel environment of each narrow beam and therefore does not know the appropriate transmission power when transmitting the PL and PRACH of the beam. Therefore, the previous SSB (Legacy SSBs) is received from the gNB. The previous SSB is as follows Figure 1A The figure shows the SSBs corresponding to each narrow beam. This allows the UE to determine the channel environment (e.g., path loss) for the optimal beam. This method of SSB transmission is equivalent to the hybrid SSB transmission described above.

[0110] The UE then transmits the PRACH corresponding to the determined SSB to the gNB using the determined beam (the determined beam's PL). This allows the gNB to know the optimal beam determined by the UE. The gNB then uses this optimal beam to send RRC signaling and other information to the UE.

[0111] According to this embodiment, even when the UE does not accurately grasp the channel environment of each narrow beam, it can determine the channel environment (for example, path loss) of the optimal beam.

[0112] [Method 2-3]

[0113] Figure 11This diagram illustrates an example of the processing between a terminal and a base station in Example 2-3. The base station (gNB) transmits a new SSB (or a previous SSB) to the terminal (UE). Based on the received SSB, the UE uses any of the methods described in the first embodiment to determine the optimal beam (or a list of RSRPs for each SSB) and the path loss (PL) for that SSB. At this point, because the UE does not accurately understand the channel environment for each narrow beam, it does not know the appropriate PL for each beam or the appropriate transmit power for the PRACH. Therefore, the UE transmits the PRACH using the wide beam / multiple beams corresponding to the new SSB (based on the path loss for that SSB).

[0114] The UE then receives Message 2 and transmits Message 3 using the wide beam / multiple beams corresponding to the new SSB. The UE may also transmit Message 3 along with the index of the optimal beam or a list of RSRPs for the SSBs. Furthermore, upon receiving both MSG 3 and the list of RSRPs for the SSBs, the gNB determines the optimal beam based on the list. The gNB uses the determined optimal beam (or notified by the UE) to transmit RRC signaling and other information to the UE.

[0115] According to this embodiment, even when the UE does not accurately grasp the channel environment of each narrow beam and does not receive legacy SSBs as in embodiment 2-2, it is possible to inform the base station of the optimal beam.

[0116] <Third embodiment>

[0117] The following two methods are considered to align the positions of the beams used in communication between the gNB and the UE.

[0118] [Method 3-1]

[0119] In method 3-1, the UE detects and reports the index of the best beam. In this case, the gNB configures or instructs the SSB transmission method through higher layer signaling or physical layer signaling. Based on this configuration or instruction, the UE detects and reports the index of the best beam during the RACH process. The SSB transmission method may also be specified in the specification. This example is equivalent to the examples in methods 2-1 to 2-3 of the second embodiment (except that in method 3, the UE transmits a list of RSRPs for SSBs).

[0120] Regarding the processing of method 3-1, use Figure 12 The gNB uses the example of the first embodiment (for example, Figure 1C 、 Figures 2 to 4) to transmit SSBs corresponding to wide beams or multiple narrow beams to the UE (S101). The gNB configures / specifies the SSB transmission method and corresponding parameters (K and M, or L and K) to the UE using the Master Information Block (MIB) / System Information Block 1 (SIB1) (S102). K, M, and L will be discussed later.

[0121] The UE monitors at least one SSB burst, decodes as many SSBs as possible, and measures RSRP (S103). By decoding multiple SSBs and measuring RSRP, the UE can accurately find the optimal beam. The UE then detects (determines) the optimal beam index using any of the methods described in the first embodiment (S104).

[0122] The UE sends a RACH preamble to the gNB ( S105 ). Regarding S105 , any of the following three options can be applied.

[0123] [Option 1]

[0124] PRACH resources are not associated with SSB indices but with beam indices. The UE transmits a RACH preamble in a resource having the index of the determined optimal beam.

[0125] [Option 2]

[0126] The UE simultaneously transmits multiple preambles on PRACH resources associated with the multiple detected SSBs. These multiple SSBs can also include SSBs corresponding to narrow beams and SSBs corresponding to wide beams. In this option, the gNB assumes the same (specific) preamble is sent from the same UE. If multiple UEs select the same preamble, a collision occurs. To mitigate such collisions, expanding the preamble space is being considered.

[0127] [Option 3]

[0128] The UE does not send the beam index on the RACH, but sends (reports) the beam index in MSG3 described later.

[0129] The UE transmits RACH MSG3 ( S106 ). If Option 3 is applied in S105 , the UE transmits the index of the best beam detected in S104 in RACH MSG3 .

[0130] The gNB configures QCL for the UE ( S107 ). Regarding S107 , either of the following two options may be applied.

[0131] [Option 1]

[0132] The gNB sets 1 SSB as the source RS of QCL.

[0133] [Option 2]

[0134] Instead of specifying a single SSB index, the gNB sets a beam index or a set of SSBs as a single QCL source. Measurement values ​​corresponding to the beam or SSB set may also be added.

[0135] [Method 3-2]

[0136] The UE sends a list of measurement results (e.g., RSRP / SINR) for multiple SSBs to the gNB. Based on the received measurement results, the gNB determines the index of the optimal beam. In this case, the gNB pre-configures or instructs the UE, via higher layer signaling or physical layer signaling, to report a list of SSB measurement results within an SSB burst. Based on this configuration or instruction, the UE transmits the SSB detection results. This example is equivalent to the example in Mode 3 of the second embodiment, where the UE transmits a list of RSRPs for SSBs. The RSRP may also be the RSRP measured for SSBs corresponding to wide beams or multiple beams.

[0137] Regarding the processing of method 3-2, use Figure 13 The gNB uses the example of the first embodiment (for example, Figure 1C 、 Figures 2 to 4 ), the gNB sends the SSB corresponding to the wide beam or multiple narrow beams to the UE (S201). The gNB can also configure / specify the SSB transmission method to the UE through the MIB. The gNB then sends SIB1 to the UE (S202).

[0138] The UE monitors at least one SSB burst, decodes as many SSBs as possible, and detects RSRP ( S203 ).

[0139] The UE sends a RACH preamble to the gNB ( S204 ). The UE then sends a RACH MSG3 ( S205 ). The UE may also include a list of successfully decoded SSBs and the RSRP (e.g., a 1- or 2-bit RSRP value) in the RACH MSG3.

[0140] The gNB configures QCL for the UE ( S206 ). Regarding S206 , either of the following two options may be applied.

[0141] [Option 1]

[0142] The gNB sets 1 SSB as the source RS of QCL.

[0143] [Option 2]

[0144] Instead of using a single SSB index, the gNB sets a beam index or a set of SSBs as a single QCL source. Measurements corresponding to the beam or SSB set can also be performed.

[0145] [Comparison with conventional NR]

[0146] The time and frequency domain positions of SSBs and the number of SSBs are the same as in conventional NR. This disclosure differs from conventional systems in that it allows mapping (associating) a single SSB with multiple beams (or multiple SSBs corresponding to multiple beams). Alternatively, it differs from conventional systems in that it allows mapping (associating) a single SSB with multiple SSBs. This mapping can also be configured or indicated to the UE via higher layer signaling or physical layer signaling. These multiple beams can also be the narrow beams described above. An SSB associated with multiple SSBs can also be used as an SSB for metering beam search.

[0147] This is similar to conventional NR systems in that the UE detects SSBs and initiates (transmits) RACH on resources corresponding to one SSB selected based on RSRP, etc. The UE in this disclosure monitors at least one SSB burst (which may extend beyond radio frame boundaries) and detects as many SSBs as possible (e.g., method 3-2).

[0148] The additional information reported during the RACH procedure may include the index of the best beam or information used to derive the index of the best beam (e.g., a list of RSRPs for SSBs). When hybrid SSB transmission is used, the UE may transmit (report) the index of the SSB transmitted using a narrow beam instead of the beam index.

[0149] Instead of a single SSB index, a beam index or a set of SSBs (for example, SSBs corresponding to a narrow beam) may be added as a single QCL source. Measurements corresponding to the beam or SSB set may also be performed.

[0150] <Details about each method>

[0151] The following describes the details of each method in detail by comparing it with conventional NR. The following contents are details of any one of the embodiments or additional matters.

[0152] [Notice from K, M, and L]

[0153] Option 1

[0154] The UE may also be specified by the specification for at least one of M, K, and L, which are used to determine the maximum number of corresponding beams. As described above, M is the total number of beams, L is the number of layers (depth / stage), and K is the number of beams within each layer (the number of beams measured). L is determined based on the number of beams corresponding to one SSB.

[0155] Option 2

[0156] The UE may also receive (be configured / indicated) information indicating at least one of M, K, and L through higher layer signaling / physical layer signaling. The UE may also receive an index indicating the value of each of M, K, and L, or a combination of M, K, and L, using (modulation of) at least one of the PSS / SSS, PBCH, and SIB1. The correspondence between the combination and the index may also be specified by the specification.

[0157] Option 3

[0158] In the case where the SSB list is reported in MSG3 (for example, method 2-3), the UE may not be set / indicated with M, K, and L.

[0159] Option 4

[0160] When hybrid SSB transmission is applied (e.g., mode 2-2), the UE can also receive SSB transmission modes in addition to M, K, and L. In this case, the UE uses PBCH or modulated PSS / SSS and is instructed to use the conventional SSB (e.g., reference mode 2-2) through 1-bit information. Figure 1A ) or a new SSB (e.g. reference Figure 1C ) In addition, the index range of the previous SSB / new SSB can also be notified through PBCH / SIB1.

[0161] [Notice of SSB delivery method]

[0162] Option 1

[0163] The SSB transmission method is not notified. In this case, the new SSB transmission is set as the default transmission method. That is, only the new SSB transmission is used. In this case, mixed SSB transmission can be supported or not supported.

[0164] Option 2

[0165] The UE may also receive a 1-bit indication indicating whether the new SSB transmission is supported. This indication may be modulated as PSS / SSS or may use PBCH or SIB1. If the new SSB transmission is supported, it may support hybrid SSB or not.

[0166] Option 3

[0167] A specific combination of M, K, and L (M=K, L=1) is set. This setting can also refer to the traditional SSB transmission method. Furthermore, while only the new SSB transmission method is supported, this specific combination allows a fallback to the traditional SSB transmission method if the gNB does not have a large number of beams.

[0168] [UE operation]

[0169] Monitor at least one SSB burst, detect at least one SSB with a sufficient RSRP (RSRP above a threshold), and then record the RSRP of all received SSBs. By recording the RSRP of all SSBs, the UE can transmit MSG3 along with a list of SSB RSRPs, as in methods 2-3. If configured to report beam indexes, a beam index detection algorithm can also be used.

[0170] [SIB1 Receive]

[0171] Similar to NR, the UE can also use the position associated with the successfully decoded SSB for decoding SIB1.

[0172] [RACH preamble]

[0173] Option 1

[0174] As with conventional NR, the UE can also transmit a RACH preamble (PRACH) corresponding to the selected SSB. The UE can also use other RACH / RRC signaling to report the optimal beam index and RSRP. The UE selects a single SSB to access the network, and the gNB communicates using the beam pattern (mode) corresponding to that SSB until the narrow beam is reported.

[0175] Option 2

[0176] PRACH resources are not associated with SSB indices but with beam indices. The UE transmits a RACH preamble on a resource with the index of the determined optimal beam.

[0177] Option 3

[0178] The UE may also transmit multiple RACH preambles on PRACH resources associated with multiple detected SSBs. Preambles from a single UE can use the same preamble root sequence (Cv) or a specific Cv pattern. Different UEs select the preamble root randomly. After transmitting the PRACH, the UE detects the random access response (RAR) at all corresponding locations where the PRACH was transmitted.

[0179] Option 4

[0180] The UE may also modulate the beam index into the RACH preamble without modifying other parts of the PRACH. In other words, different RACH preambles may be sent according to the beam index.

[0181] Option 5

[0182] In hybrid SSB transmission, PRACH resources are associated only with specific SSBs (e.g., narrow beams corresponding to previous SSBs). After the UE detects the best SSB (the one with the highest RSRP) among the specific SSBs, it can also transmit the RACH preamble corresponding to that SSB.

[0183] [Messages other than RACH]

[0184] The information sent in options 1 to 4 below is sent, for example, in message 3 after PRACH, but is not limited to message 3, and may also be sent in PUCCH (UCI), PUSCH, etc.

[0185] Option 1

[0186] The UE may also send the best beam index to the gNB in ​​Message 3.

[0187] Option 2

[0188] The UE may also send the measured or successfully decoded (measured) RSRP of all SSBs to the gNB.

[0189] Option 3

[0190] The UE may also send the beam index or RSRP of the SSB set in other specific RRC signals to the gNB.

[0191] Option 4

[0192] In the case of hybrid SSB transmission, the UE may also send the index of the SSB transmitted via the narrow beam to the gNB instead of the index of the narrow beam.

[0193] [QCL concept]

[0194] The QCL concept in RACH / RRC signaling is explained.

[0195] Before the UE reports the beam index or RSRP of the SSB set, the UE may also assume that the gNB uses the same beam pattern (mode) associated with the PRACH resources used in the transmission of the preamble in its communications with the UE.

[0196] Alternatively, after the UE reports the beam index or RSRP of the SSB set, the UE assumes that the gNB communicates with the UE using a UE-specific narrow beam for subsequent channel / signal (e.g., PUCCH / PUSCH) transmissions.

[0197] [QCL source]

[0198] Option 1

[0199] The UE is set with 1 SSB index as the QCL source RS.

[0200] Option 2

[0201] Instead of one SSB index, a beam index or a set of SSBs is used as one QCL source.

[0202] [Measurement]

[0203] Regarding the QCL source, when Option 2 is applied, multiple SSBs may be measured, and in addition to the RSRP, RSRQ, and SINR of the SSBs, the RSRP, RSRQ, and SINR of the beam may also be measured / calculated. The beam may be a narrow beam or a wide beam.

[0204] <Supplement>

[0205] [Notification of information to UE]

[0206] In the above-mentioned embodiment, notification of arbitrary information from the network (NW) (e.g., from a base station (BS)) to the UE (in other words, reception of arbitrary information from the BS in the UE) may also be performed using physical layer signaling (e.g., DCI), higher layer signaling (e.g., RRC signaling, MAC CE), specific signals / channels (e.g., PDCCH, PDSCH, reference signals), or a combination thereof.

[0207] When the notification is performed through a MAC CE, the MAC CE may be identified by including a new logical channel ID (LCID) not specified in existing specifications in the MAC subheader.

[0208] When the above notification is performed through DCI, the above notification may be performed through a specific field of the DCI, a Radio Network Temporary Identifier (RNTI) used in scrambling cyclic redundancy check (CRC) bits assigned to the DCI, the format of the DCI, and the like.

[0209] In addition, notification of any information in the above-mentioned embodiments to the UE may be performed periodically, semi-continuously, or aperiodically.

[0210] [Notification of information from UE]

[0211] The notification of arbitrary information from the UE (to the NW) in the above-mentioned embodiment (in other words, the sending / reporting of arbitrary information from the UE to the BS) can also be performed using physical layer signaling (e.g., UCI), high-layer signaling (e.g., RRC signaling, MAC CE), specific signals / channels (e.g., PUCCH, PUSCH, PRACH, reference signals), or a combination thereof.

[0212] When the above notification is performed through MAC CE, the MAC CE can also be identified by including a new LCID that is not specified in the existing specifications in the MAC subheader.

[0213] When the notification is performed through UCI, the notification may be transmitted using PUCCH or PUSCH.

[0214] Furthermore, the notification of arbitrary information from the UE in the above-mentioned embodiments may be performed periodically, semi-continuously, or aperiodically.

[0215] [Regarding the application of each embodiment]

[0216] At least one of the above embodiments may also be applied when a specific condition is met, which may be specified in the specification or notified to the UE / BS using higher layer signaling / physical layer signaling.

[0217] At least one of the above-mentioned embodiments may also be applied only to a UE that reports a specific UE capability (UE capability) or supports the specific UE capability.

[0218] The specific UE capability may also indicate at least one of the following:

[0219] Supporting specific processing / operation / control / information related to at least one of the above embodiments.

[0220] Support for new SSB transmission methods / optimal beam determination methods (e.g. Figure 1C 、 Figures 2-4 ).

[0221] Supported values ​​of M, K, and L.

[0222] In addition, the above-mentioned specific UE capabilities can be capabilities that are applied across all frequencies (commonly regardless of frequency), or capabilities for each frequency (for example, one or a combination of cells, bands, band combinations, BWPs, component carriers, etc.), or capabilities for each frequency range (for example, Frequency Range 1 (FR1), FR2, FR3, FR4, FR5, FR2-1, FR2-2), or capabilities for each subcarrier spacing (SubCarrier Spacing (SCS)), or capabilities for each feature set (Feature Set (FS)) or each feature set (Feature Set Per Component-carrier (FSPC)) of each component carrier.

[0223] Furthermore, the specific UE capability may be a capability applied across all duplex modes (commonly regardless of the duplex mode) or a capability for each duplex mode (eg, time division duplex (TDD) or frequency division duplex (FDD)).

[0224] In addition, at least one of the above embodiments may also be applied when specific information associated with the above embodiments is set / activated / triggered by the UE through higher layer signaling / physical layer signaling (or the operation of the above embodiments is performed). For example, the specific information may also indicate activation / deactivation of a new SSB transmission mode / optimal beam determination method (for example, Figure 1C 、 Figures 2-4 ) information, arbitrary RRC parameters for a specific version (for example, Rel.18 / 19), etc.

[0225] When the UE does not support at least one of the above-mentioned specific UE capabilities or is not configured with the above-mentioned specific information, for example, the Rel.15 / 16 operations may also be applied.

[0226] (Note)

[0227] The following inventions are added to one embodiment of the present disclosure.

[0228] [Note 1]

[0229] A terminal having:

[0230] a receiving unit that receives information indicating the total number of beams, the number of layers, and the number of beams in each layer; and

[0231] The control unit measures synchronization signal blocks (SSBs) corresponding to a set of multiple beams in each layer, and determines an index of an optimal beam based on the measurement result.

[0232] [Note 2]

[0233] The terminal as described in Appendix 1, wherein

[0234] The control unit compares the reception powers of the plurality of SSBs in the layer, and determines the index of the optimal beam based on the SSB having the highest reception power in each layer.

[0235] [Note 3]

[0236] A terminal as described in Appendix 1 or Appendix 2, wherein:

[0237] The receiving unit receives each beam included in the set of the plurality of beams,

[0238] The control unit detects the path loss of each beam.

[0239] [Note 4]

[0240] A terminal as described in any one of Appendix 1 to Appendix 3, wherein:

[0241] The receiving unit receives an indication indicating whether transmission of a synchronization signal block (SSB) corresponding to the set of the plurality of beams is supported.

[0242] (Note)

[0243] The following inventions are added to one embodiment of the present disclosure.

[0244] [Note 1]

[0245] A terminal having:

[0246] a control unit that measures synchronization signal blocks (SSBs) corresponding to a set of multiple beams in each layer and determines an index of an optimal beam based on the measurement result; and

[0247] The transmitting unit transmits a physical random access channel (PRACH) corresponding to the index of the best beam.

[0248] [Note 2]

[0249] The terminal as described in Appendix 1, wherein

[0250] The control unit compares the reception powers of the plurality of SSBs in the layer, and determines the index of the optimal beam based on the SSB having the highest reception power in each layer.

[0251] [Note 3]

[0252] A terminal as described in Appendix 1 or Appendix 2, wherein:

[0253] The receiving unit receives each beam included in the set of the plurality of beams,

[0254] The control unit detects the path loss of each beam.

[0255] [Note 4]

[0256] A terminal as described in any one of Appendix 1 to Appendix 3, wherein:

[0257] The index of the optimal beam is used as the QCL source.

[0258] (Wireless Communication System)

[0259] The following describes a configuration of a wireless communication system according to an embodiment of the present disclosure. In this wireless communication system, communication is performed using any one of the wireless communication methods according to the above-described embodiments of the present disclosure or a combination thereof.

[0260] Figure 14 This figure shows an example of a schematic configuration of a wireless communication system according to one embodiment. Wireless communication system 1 (may also be simply referred to as system 1) may be a system that implements communication using Long Term Evolution (LTE) standardized by the Third Generation Partnership Project (3GPP) or the fifth-generation mobile communication system New Radio (5G NR).

[0261] In addition, the wireless communication system 1 may also support dual connectivity between multiple radio access technologies (Radio Access Technologies (RATs)) (Multi-RAT Dual Connectivity (MR-DC)). MR-DC may also include dual connectivity between LTE (Evolved Universal Terrestrial Radio Access (E-UTRA)) and NR (E-UTRA-NR Dual Connectivity (EN-DC)), dual connectivity between NR and LTE (NR-E-UTRA Dual Connectivity (NE-DC)), and the like.

[0262] In EN-DC, the LTE (E-UTRA) base station (eNB) is the Master Node (MN), and the NR base station (gNB) is the Secondary Node (SN). In NE-DC, the NR base station (gNB) is the MN, and the LTE (E-UTRA) base station (eNB) is the SN.

[0263] The wireless communication system 1 may also support dual connectivity between multiple base stations within the same RAT (for example, dual connectivity (NR-NR Dual Connectivity (NN-DC)) in which both the MN and the SN are NR base stations (gNB)).

[0264] The wireless communication system 1 may also include a base station 11 that forms a macrocell C1 with relatively wide coverage, and base stations 12 (12a-12c) that are deployed within the macrocell C1 and form small cells C2 that are narrower than the macrocell C1. User terminals 20 may also be located within at least one of the cells. The arrangement and number of cells and user terminals 20 are not limited to those shown in the figure. Hereinafter, when not distinguishing between base stations 11 and 12, they are collectively referred to as base stations 10.

[0265] The user terminal 20 may be connected to at least one of the multiple base stations 10. The user terminal 20 may utilize at least one of carrier aggregation (CA) using multiple component carriers (CCs) and dual connectivity (DC).

[0266] Each CC may be included in at least one of a first frequency band (Frequency Range 1 (FR1)) and a second frequency band (Frequency Range 2 (FR2)). Macrocell C1 may be included in FR1, and small cell C2 may be included in FR2. For example, FR1 may be a frequency band below 6 GHz (sub-6 GHz), and FR2 may be a frequency band higher than 24 GHz (above-24 GHz). The frequency bands and definitions of FR1 and FR2 are not limited to these. For example, FR1 may correspond to a frequency band higher than FR2.

[0267] Furthermore, the user terminal 20 may perform communication using at least one of time division duplex (TDD) and frequency division duplex (FDD) in each CC.

[0268] Multiple base stations 10 may be connected via wired (e.g., optical fiber based on the Common Public Radio Interface (CPRI), an X2 interface, etc.) or wireless (e.g., NR communication). For example, when NR communication is used as a backhaul between base stations 11 and 12, base station 11, which functions as a host station, may be referred to as an Integrated Access Backhaul (IAB) donor, and base station 12, which functions as a relay station (relay), may be referred to as an IAB node.

[0269] The base station 10 may be connected to the core network 30 via other base stations 10 or directly. The core network 30 may include, for example, at least one of an evolved packet core (EPC), a 5G core network (5GCN), and a next generation core (NGC).

[0270] The core network 30 may also include network functions (NFs), such as the User Plane Function (UPF), Access and Mobility Management Function (AMF), Session Management Function (SMF), Unified Data Management (UDM), Application Function (AF), Data Network (DN), Location Management Function (LMF), and Operation, Administration, and Maintenance (Management) (OAM). Furthermore, a single network node may provide multiple functions. Furthermore, communication with external networks (e.g., the Internet) may also be conducted via the DN.

[0271] The user terminal 20 may also be a terminal that supports at least one of communication methods such as LTE, LTE-A, and 5G.

[0272] In the wireless communication system 1 , a radio access scheme based on orthogonal frequency division multiplexing (OFDM) may be used. For example, in at least one of the downlink (DL) and uplink (UL), cyclic prefix OFDM (CP-OFDM), discrete Fourier transform spread OFDM (DFT-s-OFDM), orthogonal frequency division multiple access (OFDMA), or single carrier frequency division multiple access (SC-FDMA) may be used.

[0273] The radio access scheme may also be referred to as a waveform. In addition, in the wireless communication system 1 , other radio access schemes (eg, other single-carrier transmission schemes, other multi-carrier transmission schemes) may be used as the UL and DL radio access schemes.

[0274] As downlink channels, the wireless communication system 1 may use a downlink shared channel (Physical Downlink Shared Channel (PDSCH)) shared by each user terminal 20 , a broadcast channel (Physical Broadcast Channel (PBCH)), a downlink control channel (Physical Downlink Control Channel (PDCCH)), etc.

[0275] In addition, as uplink channels, the wireless communication system 1 can also use an uplink shared channel (Physical Uplink Shared Channel (PUSCH)) shared by each user terminal 20, an uplink control channel (Physical Uplink Control Channel (PUCCH)), a random access channel (Physical Random Access Channel (PRACH)), etc.

[0276] User data, higher-layer control information, and system information blocks (SIBs) are transmitted via the PDSCH. User data and higher-layer control information can also be transmitted via the PUSCH. Furthermore, the Master Information Block (MIB) can also be transmitted via the PBCH.

[0277] The lower layer control information may also be transmitted via the PDCCH. The lower layer control information may include, for example, downlink control information (Downlink Control Information (DCI)) including scheduling information for at least one of the PDSCH and the PUSCH.

[0278] In addition, the DCI that schedules the PDSCH may also be referred to as DL allocation, DL DCI, etc., and the DCI that schedules the PUSCH may also be referred to as UL grant, UL DCI, etc. In addition, the PDSCH may also be rewritten as DL data, and the PUSCH may also be rewritten as UL data.

[0279] PDCCH detection also utilizes control resource sets (CORESETs) and search spaces. A CORESET corresponds to the resources used to search for DCI. A search space corresponds to the search area and search method for PDCCH candidates. A CORESET can be associated with one or more search spaces. Based on the search space configuration, the UE can monitor the CORESETs associated with a particular search space.

[0280] A search space may also correspond to PDCCH candidates corresponding to one or more aggregation levels. One or more search spaces may also be referred to as a search space set. Furthermore, the terms "search space," "search space set," "search space configuration," "search space set configuration," "CORESET," and "CORESET configuration" in this disclosure may be interchangeable.

[0281] The PUCCH can also transmit uplink control information (uplink control information (UCI)) including at least one of channel state information (CSI), delivery confirmation information (e.g., also known as hybrid automatic repeat request ACKnowledgement (HARQ-ACK), ACK / NACK, etc.), and scheduling request (SR). The PRACH can also transmit the random access preamble used to establish a connection with a cell.

[0282] In the present disclosure, downlink, uplink, etc. may be expressed without the word “link.” Furthermore, various channels may be expressed without the word “physical” at the beginning.

[0283] In the wireless communication system 1, a synchronization signal (SS), a downlink reference signal (DL-RS), and the like may also be transmitted. As DL-RSs, in the wireless communication system 1, a cell-specific reference signal (CRS), a channel state information reference signal (CSI-RS), a demodulation reference signal (DMRS), a positioning reference signal (PRS), and a phase tracking reference signal (PTRS) may also be transmitted.

[0284] For example, a synchronization signal may be at least one of a primary synchronization signal (PSS) and a secondary synchronization signal (SSS). A signal block containing SSs (PSS, SSS) and PBCHs (and DMRS for the PBCH) may also be referred to as an SS / PBCH block or an SS block (SSB). Furthermore, SSs and SSBs may also be referred to as reference signals.

[0285] In addition, wireless communication system 1 may also transmit a sounding reference signal (SRS) or a demodulation reference signal (DMRS) as an uplink reference signal (UL-RS). DMRS is also called a user terminal-specific reference signal (UE-specific Reference Signal).

[0286] (Base Station)

[0287] Figure 15This figure shows an example of the configuration of a base station according to one embodiment. The base station 10 includes a control unit 110, a transceiver unit 120, a transceiver antenna 130, and a transmission path interface (transmission line interface) 140. Furthermore, one or more of each of the control unit 110, the transceiver unit 120, the transceiver antenna 130, and the transmission path interface 140 may be provided.

[0288] In addition, in this example, the functional blocks of the characteristic parts of this embodiment are mainly shown, and it is also conceivable that the base station 10 also has other functional blocks required for wireless communication. Part of the processing of each unit described below may also be omitted.

[0289] The control unit 110 controls the entire base station 10. The control unit 110 can be composed of a controller, a control circuit, and the like that are described based on common knowledge in the technical field to which this disclosure relates.

[0290] The control unit 110 may also control signal generation, scheduling (e.g., resource allocation, mapping), etc. It may also control transmission, reception, and measurement using the transceiver unit 120, the transceiver antenna 130, and the transmission path interface 140. The control unit 110 may also generate data, control information, sequences, etc. to be transmitted as signals and forward them to the transceiver unit 120. The control unit 110 may also perform call processing (e.g., setup and release) of communication channels, manage the status of the base station 10, and manage radio resources.

[0291] Transmitter / receiver unit 120 may also include a baseband unit 121, a radio frequency (RF) unit 122, and a measurement unit 123. Baseband unit 121 may also include a transmit processing unit 1211 and a receive processing unit 1212. Transmitter / receiver unit 120 may include a transmitter / receiver, RF circuits, baseband circuits, filters, phase shifters, measurement circuits, transmit / receive circuits, and the like, as described based on common knowledge in the technical fields involved in this disclosure.

[0292] The transmitting and receiving unit 120 may be configured as an integrated transmitting and receiving unit or may be configured as a transmitting unit and a receiving unit. The transmitting unit may also be configured as a transmitting processing unit 1211 and an RF unit 122. The receiving unit may also be configured as a receiving processing unit 1212, an RF unit 122, and a measuring unit 123.

[0293] The transmitting and receiving antenna 130 can be formed of an antenna described based on common knowledge in the technical field to which this disclosure relates, such as an array antenna.

[0294] The transmitting and receiving unit 120 may also transmit the aforementioned downlink channel, synchronization signal, downlink reference signal, etc. The transmitting and receiving unit 120 may also receive the aforementioned uplink channel, uplink reference signal, etc.

[0295] The transmitting and receiving unit 120 may also use digital beamforming (eg, precoding), analog beamforming (eg, phase rotation), etc. to form at least one of a transmitting beam and a receiving beam.

[0296] The transmitting and receiving unit 120 (transmitting processing unit 1211) may perform processing at the Packet Data Convergence Protocol (PDCP) layer, processing at the Radio Link Control (RLC) layer (e.g., RLC retransmission control), processing at the Medium Access Control (MAC) layer (e.g., HARQ retransmission control), etc. on the data and control information obtained from the control unit 110, to generate a bit string to be transmitted.

[0297] The transmitting and receiving unit 120 (transmitting processing unit 1211) may also perform transmission processing such as channel coding (which may also include error correction coding), modulation, mapping, filter processing (filtering processing), discrete Fourier transform (DFT) processing (as needed), inverse fast Fourier transform (IFFT) processing), precoding, digital-to-analog conversion, etc. on the bit sequence to be transmitted, and output a baseband signal.

[0298] The transmitting and receiving unit 120 (RF unit 122 ) may also perform modulation, filter processing, amplification, etc. on the baseband signal to a radio frequency band, and transmit the signal in the radio frequency band via the transmitting and receiving antenna 130 .

[0299] Meanwhile, the transmitting and receiving unit 120 (RF unit 122 ) may also perform amplification, filter processing (filtering), and demodulation into baseband signals on the radio frequency band signals received via the transmitting and receiving antenna 130 .

[0300] The transmitting and receiving unit 120 (receiving processing unit 1212) may also apply receiving processing such as analog-to-digital conversion, fast Fourier transform (FFT) processing, inverse discrete Fourier transform (IDFT) processing (as needed), filter processing (filtering processing), demapping, demodulation, decoding (which may also include error correction decoding), MAC layer processing, RLC layer processing, and PDCP layer processing to the obtained baseband signal to obtain user data, etc.

[0301] The transmitting / receiving unit 120 (measuring unit 123) may also perform measurements related to received signals. For example, the measuring unit 123 may also perform radio resource management (RRM) measurements and channel state information (CSI) measurements based on the received signals. The measuring unit 123 may also measure received power (e.g., Reference Signal Received Power (RSRP)), received quality (e.g., Reference Signal Received Quality (RSRQ), Signal to Interference plus Noise Ratio (SINR), Signal to Noise Ratio (SNR)), signal strength (e.g., Received Signal Strength Indicator (RSSI)), and propagation path information (e.g., CSI). The measurement results may also be output to the control unit 110.

[0302] The transmission path interface 140 can also send and receive signals (return signaling) between the devices included in the core network 30 (for example, the network node providing NF), other base stations 10, etc., and obtain and transmit user data (user plane data), control plane data, etc. for the user terminal 20.

[0303] In addition, the transmitting unit and the receiving unit of the base station 10 in the present disclosure may also be composed of at least one of the transmitting and receiving unit 120 , the transmitting and receiving antenna 130 , and the transmission path interface 140 .

[0304] Furthermore, the transmitting and receiving unit 120 may also transmit information indicating the total number of beams, the number of layers, and the number of beams within each layer. The control unit 110 may also transmit a synchronization signal block (SSB) corresponding to a set of multiple beams for each layer, and control transmission based on the index of the optimal beam determined based on the measurement results.

[0305] The control unit 110 may also control the transmission of synchronization signal blocks (SSBs) corresponding to the set of multiple beams of each layer. The transmitting and receiving unit 120 may also receive a physical random access channel (PRACH) corresponding to the index of the best beam determined based on the measurement results of the SSBs.

[0306] (User Terminal)

[0307] Figure 16 This figure shows an example of the configuration of a user terminal according to one embodiment. The user terminal 20 includes a control unit 210, a transmitting / receiving unit 220, and a transmitting / receiving antenna 230. Furthermore, the control unit 210, the transmitting / receiving unit 220, and the transmitting / receiving antenna 230 may each be provided in one or more units.

[0308] In addition, in this example, the functional blocks of the characteristic parts of this embodiment are mainly shown, and it is also assumed that the user terminal 20 also has other functional blocks required for wireless communication. Part of the processing of each unit described below may also be omitted.

[0309] The control unit 210 controls the entire user terminal 20. The control unit 210 can be composed of a controller, a control circuit, and the like that are described based on common knowledge in the technical field to which this disclosure relates.

[0310] The control unit 210 may also control signal generation, mapping, etc. The control unit 210 may also control transmission, reception, measurement, etc. using the transmission and reception unit 220 and the transmission and reception antenna 230. The control unit 210 may also generate data, control information, sequences, etc. to be transmitted as signals and forward them to the transmission and reception unit 220.

[0311] The transceiver unit 220 may also include a baseband unit 221, an RF unit 222, and a measurement unit 223. The baseband unit 221 may also include a transmission processing unit 2211 and a reception processing unit 2212. The transceiver unit 220 may include a transmitter / receiver, an RF circuit, a baseband circuit, a filter, a phase shifter, a measurement circuit, a transceiver circuit, and the like, which are described based on common knowledge in the technical fields involved in this disclosure.

[0312] The transmitting and receiving unit 220 may be configured as an integrated transmitting and receiving unit or may be composed of a transmitting unit and a receiving unit. The transmitting unit may also be composed of a transmitting processing unit 2211 and an RF unit 222. The receiving unit may also be composed of a receiving processing unit 2212, an RF unit 222, and a measuring unit 223.

[0313] The transmitting and receiving antenna 230 can be formed of an antenna described based on common knowledge in the technical field involved in the present disclosure, such as an array antenna.

[0314] The transmitting and receiving unit 220 may also receive the aforementioned downlink channel, synchronization signal, downlink reference signal, etc. The transmitting and receiving unit 220 may also transmit the aforementioned uplink channel, uplink reference signal, etc.

[0315] The transmitting and receiving unit 220 may also use digital beamforming (eg, precoding), analog beamforming (eg, phase rotation), etc. to form at least one of a transmit beam and a receive beam.

[0316] The transmitting and receiving unit 220 (transmitting processing unit 2211) may also perform PDCP layer processing, RLC layer processing (e.g., RLC retransmission control), MAC layer processing (e.g., HARQ retransmission control), etc. on the data and control information obtained from the control unit 210, and generate a bit string to be transmitted.

[0317] The transmitting and receiving unit 220 (transmitting processing unit 2211) can also perform channel coding (which may also include error correction coding), modulation, mapping, filter processing (filtering processing), DFT processing (as needed), IFFT processing, precoding, digital-to-analog conversion and other transmission processing on the bit string to be transmitted, and output a baseband signal.

[0318] Furthermore, whether DFT processing is applied may also be determined based on the transform precoding configuration. For a particular channel (e.g., PUSCH), if transform precoding is enabled, the transceiver unit 220 (transmit processing unit 2211) may perform DFT processing as part of the aforementioned transmit processing in order to transmit the channel using a DFT-s-OFDM waveform. Otherwise, the transceiver unit 220 (transmit processing unit 2211) may perform DFT processing as part of the aforementioned transmit processing.

[0319] The transmitting and receiving unit 220 (RF unit 222 ) may also perform modulation, filter processing (filtering), amplification, etc. on the baseband signal to a radio frequency band, and transmit the signal in the radio frequency band via the transmitting and receiving antenna 230 .

[0320] Meanwhile, the transmitting and receiving unit 220 (RF unit 222 ) may also perform amplification, filter processing (filtering processing), and demodulation into a baseband signal on the radio frequency band signal received via the transmitting and receiving antenna 230 .

[0321] The transmitting and receiving unit 220 (receiving processing unit 2212) may also apply receiving processing such as analog-to-digital conversion, FFT processing, IDFT processing (as needed), filter processing (filtering processing), demapping, demodulation, decoding (which may also include error correction decoding), MAC layer processing, RLC layer processing, and PDCP layer processing to the obtained baseband signal, and obtain user data, etc.

[0322] The transmitting / receiving unit 220 (measuring unit 223) may also perform measurements related to received signals. For example, the measuring unit 223 may also perform RRM measurements and CSI measurements based on the received signals. The measuring unit 223 may also measure received power (e.g., RSRP), received quality (e.g., RSRQ, SINR, SNR), signal strength (e.g., RSSI), propagation path information (e.g., CSI), etc. The measurement results may also be output to the control unit 210.

[0323] In addition, the transmitting unit and the receiving unit of the user terminal 20 in the present disclosure may also be composed of at least one of the transmitting and receiving unit 220 and the transmitting and receiving antenna 230 .

[0324] In addition, the transmitting and receiving unit 220 may also receive information indicating the total number of beams, the number of layers, and the number of beams in each layer (corresponding to M, L, and K).

[0325] The control unit 210 may also measure synchronization signal blocks (SSBs) corresponding to a set of multiple beams in each layer, and determine an optimal beam index based on the measurement result (see the first embodiment).

[0326] The control unit 210 may also compare the received powers of the plurality of SSBs in the layer, and determine the index of the best beam based on the SSB with the highest received power in each layer (for example, referring to Figure 2 、 Figure 3 for example).

[0327] The transmitting and receiving unit 220 may also receive each beam included in the set of multiple beams. The control unit 210 may also detect the path loss of each beam (for example, refer to method 2-2).

[0328] The transmitting and receiving unit 220 may also receive an indication indicating whether transmission of a synchronization signal block (SSB) corresponding to the set of the plurality of beams is supported (see option 2 of [Notification of SSB transmission method]).

[0329] The transmitting and receiving unit 220 may also transmit a physical random access channel (PRACH) corresponding to the index of the best beam (mode 2-1, option 2 of [RACH preamble]).

[0330] The determined optimal beam index can also be used as a QCL source.

[0331] (Hardware structure)

[0332] Furthermore, the block diagrams used in the description of the above embodiments illustrate blocks of functional units. These functional blocks (structural units) are implemented by any combination of at least one of hardware and software. Furthermore, the implementation method of each functional block is not particularly limited. Specifically, each functional block can be implemented using a single device that is physically or logically combined, or by connecting two or more physically or logically separate devices directly or indirectly (e.g., by wired or wireless connections) to implement these multiple devices. A functional block can also be implemented by combining one or more of these devices with software.

[0333] Functions include, but are not limited to, judging, determining, calculating, calculating, processing, deriving, investigating, searching, confirming, receiving, sending, outputting, accessing, resolving, selecting, choosing, establishing, comparing, assuming, expecting, regarding, broadcasting, notifying, communicating, forwarding, configuring, reconfiguring, allocating, mapping, and assigning. For example, a functional block (structural unit) that implements a transmitting function may also be referred to as a transmitting unit, a transmitter, or the like. Any of these functions are as described above, and their implementation methods are not particularly limited.

[0334] For example, a base station, a user terminal, etc. in one embodiment of the present disclosure may also function as a computer that performs processing of the wireless communication method of the present disclosure. Figure 17 This figure shows an example of the hardware configuration of a base station and a user terminal according to one embodiment. The base station 10 and the user terminal 20 described above can also be physically configured as a computer device including a processor 1001, a memory 1002, a storage 1003, a communication device 1004, an input device 1005, an output device 1006, a bus 1007, and the like.

[0335] In this disclosure, the terms "device," "circuit," "equipment," "section," and "unit" are interchangeable. The hardware configuration of the base station 10 and the user terminal 20 may include one or more of the devices shown in the figures, or may exclude some of the devices.

[0336] For example, although only one processor 1001 is shown, multiple processors may be provided. Furthermore, processing may be performed by a single processor, or by two or more processors simultaneously, sequentially, or using other methods. Furthermore, processor 1001 may be implemented using more than one chip.

[0337] The functions of the base station 10 and the user terminal 20 are realized, for example, by reading specific software (program) into hardware such as the processor 1001 and the memory 1002, so that the processor 1001 performs calculations and controls communication via the communication device 1004, or controls at least one of reading and writing data in the memory 1002 and the storage 1003.

[0338] Processor 1001 controls the entire computer by, for example, operating an operating system. Processor 1001 may also be comprised of a central processing unit (CPU) including interfaces with peripheral devices, a control device, a computing device, registers, and the like. For example, at least a portion of the aforementioned control unit 110 (210) and transceiver unit 120 (220) may also be implemented by processor 1001.

[0339] Furthermore, the processor 1001 reads programs (program code), software modules, data, etc. from at least one of the storage 1003 and the communication device 1004 into the memory 1002 and executes various processes based on them. As a program, a program that causes a computer to execute at least a portion of the operations described in the above-described embodiments can be used. For example, the control unit 110 (210) can also be implemented by a control program stored in the memory 1002 and executed by the processor 1001, and the other functional blocks can also be implemented similarly.

[0340] Memory 1002 may also be a computer-readable recording medium, such as at least one of a read-only memory (ROM), an erasable programmable ROM (EPROM), an electrically erasable programmable ROM (EEPROM), a random access memory (RAM), or other suitable storage medium. Memory 1002 may also be referred to as a register, a cache, a main memory (main storage device), or the like. Memory 1002 can store executable programs (program code), software modules, and the like for implementing the wireless communication method according to an embodiment of the present disclosure.

[0341] Storage 1003 may also be a computer-readable recording medium, such as at least one of a flexible disk, a floppy disk, an optical disk (such as a compact disk (Compact Disc Read-Only Memory (CD-ROM)), a digital versatile disk, a Blu-ray disk), a removable disk, a hard disk drive, a smart card, a flash memory device (such as a card, a stick, or a key drive), a magnetic stripe, a database, a server, or other suitable storage medium. Storage 1003 may also be referred to as an auxiliary storage device.

[0342] The communication device 1004 is hardware (a transmitting and receiving device) for communicating between computers via at least one of a wired network and a wireless network. For example, it is also referred to as a network device, a network controller, a network card, a communication module, etc. In order to implement at least one of frequency division duplex (FDD) and time division duplex (TDD), the communication device 1004 may also be configured to include a high-frequency switch, a duplexer, a filter, a frequency synthesizer, etc. For example, the aforementioned transmitting and receiving unit 120 (220) and the transmitting and receiving antenna 130 (230) may also be implemented by the communication device 1004. The transmitting and receiving unit 120 (220) may also be physically or logically separated by a transmitting unit 120a (220a) and a receiving unit 120b (220b).

[0343] The input device 1005 is an input device that receives input from the outside (e.g., a keyboard, mouse, microphone, switch, button, sensor, etc.). The output device 1006 is an output device that outputs to the outside (e.g., a display, speaker, light-emitting diode (LED) lamp, etc.). Alternatively, the input device 1005 and output device 1006 may be integrated (e.g., a touch panel).

[0344] Furthermore, the processor 1001, memory 1002, and other devices are connected via a bus 1007 for communicating information. The bus 1007 may be configured as a single bus or may be configured as different buses between the devices.

[0345] Furthermore, the base station 10 and user terminal 20 may also be configured to include hardware such as a microprocessor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a programmable logic device (PLD), or a field programmable gate array (FPGA), and may use this hardware to implement part or all of each functional block. For example, the processor 1001 may be implemented using at least one of these hardware components.

[0346] (Variation)

[0347] In addition, the terms described in this disclosure and the terms required for understanding this disclosure may be replaced with terms having the same or similar meanings. For example, channel, symbol, and signal (signal or signaling) may be replaced with each other. In addition, a signal may also be a message. A reference signal may also be referred to as RS, or as a pilot, pilot signal, etc. depending on the applied standard. In addition, a component carrier (CC) may also be referred to as a cell, frequency carrier, carrier frequency, etc.

[0348] A radio frame can also be composed of one or more time periods (frames) in the time domain. Each of these one or more time periods (frames) that make up a radio frame can also be called a subframe. Furthermore, a subframe can also be composed of one or more time slots in the time domain. A subframe can also be a fixed time length (for example, 1ms) that is independent of the numerology.

[0349] Here, a parameter set may also refer to communication parameters applied to at least one of the transmission and reception of a signal or channel. For example, the parameter set may also represent at least one of subcarrier spacing (SCS), bandwidth, symbol length, cyclic prefix length, transmission time interval (TTI), the number of symbols per TTI, radio frame structure, specific filtering processing performed by the transmitter and receiver in the frequency domain, and specific windowing processing performed by the transmitter and receiver in the time domain.

[0350] In the time domain, a slot can also be composed of one or more symbols (Orthogonal Frequency Division Multiplexing (OFDM) symbols, Single Carrier Frequency Division Multiple Access (SC-FDMA) symbols, etc.) Furthermore, a slot can also be a time unit based on a parameter set.

[0351] A time slot may also contain multiple mini-slots. Each mini-slot may also consist of one or more symbols in the time domain. Furthermore, a mini-slot may also be referred to as a sub-slot. A mini-slot may also consist of fewer symbols than a time slot. A PDSCH (or PUSCH) transmitted in a time unit larger than a mini-slot may also be referred to as PDSCH (PUSCH) mapping type A. A PDSCH (or PUSCH) transmitted using mini-slots may also be referred to as PDSCH (PUSCH) mapping type B.

[0352] Radio frames, subframes, time slots, mini-slots, and symbols all represent time units used for signal transmission. Radio frames, subframes, time slots, mini-slots, and symbols may also be referred to by their respective equivalents. Furthermore, the time units of frame, subframe, time slot, mini-slot, and symbol in this disclosure may be interchangeable.

[0353] For example, a subframe can be called a TTI, multiple consecutive subframes can be called a TTI, and a slot or a mini-slot can be called a TTI. That is, at least one of a subframe and a TTI can be a subframe (1 ms) in existing LTE, a period shorter than 1 ms (for example, 1-13 symbols), or a period longer than 1 ms. Furthermore, the unit representing a TTI can be called a slot, a mini-slot, or the like, rather than a subframe.

[0354] Here, TTI refers to, for example, the minimum time unit used for scheduling in wireless communications. For example, in the LTE system, a base station schedules each user terminal by allocating radio resources (such as the frequency bandwidth and transmit power available to each user terminal) in TTI units. The definition of TTI is not limited to this.

[0355] A TTI can also be a unit of time for transmitting channel-coded data packets (transport blocks), code blocks, code words, etc., and can also be a unit of processing for scheduling, link adaptation, etc. Furthermore, when a TTI is given, the time interval (e.g., the number of symbols) to which a transport block, code block, code word, etc. is actually mapped can be shorter than the TTI.

[0356] Furthermore, while a time slot or mini-slot is referred to as a TTI, one or more TTIs (i.e., one or more time slots or one or more mini-slots) can also be the minimum time unit for scheduling. Furthermore, the number of time slots (mini-slots) that constitute this minimum time unit for scheduling can also be controlled.

[0357] A TTI with a time length of 1 ms may also be referred to as a normal TTI (TTI in 3GPP Rel. 8-12), a standard TTI, a long TTI, a normal subframe, a standard subframe, a long subframe, a time slot, etc. A TTI shorter than a normal TTI may also be referred to as a shortened TTI, a short TTI, a partial TTI (partial or fractional TTI), a shortened subframe, a short subframe, a minislot, a subslot, a time slot, etc.

[0358] In addition, a long TTI (e.g., normal TTI, subframe, etc.) can also be rewritten as a TTI with a time length exceeding 1ms, and a short TTI (e.g., shortened TTI, etc.) can also be rewritten as a TTI with a TTI length shorter than the long TTI and longer than 1ms.

[0359] A resource block (RB) is a unit of resource allocation in the time and frequency domains. In the frequency domain, it may also include one or more consecutive subcarriers (subcarriers). The number of subcarriers contained in an RB can be the same regardless of the parameter set, for example, it can be 12. The number of subcarriers contained in an RB can also be determined based on the parameter set.

[0360] In addition, an RB may also include one or more symbols in the time domain, and may also be the length of a slot, a mini-slot, a subframe, or a TTI. A TTI, a subframe, etc. may also be composed of one or more resource blocks.

[0361] In addition, one or more RBs may also be referred to as a physical resource block (Physical RB (PRB)), a sub-carrier group (SCG), a resource element group (REG), a PRB pair, an RB pair, etc.

[0362] Furthermore, a resource block may be composed of one or more resource elements (REs). For example, one RE may be a radio resource region of one subcarrier and one symbol.

[0363] A Bandwidth Part (BWP) (also known as a fractional bandwidth) can also represent a subset of contiguous common resource blocks (RBs) used for a particular parameter set within a carrier. Common RBs can also be identified by their index relative to the common reference point for that carrier. PRBs can also be defined within a BWP and numbered within that BWP.

[0364] The BWP may include a UL BWP (BWP for UL) and a DL BWP (BWP for DL). For a UE, one or more BWPs may be configured within one carrier.

[0365] At least one of the configured BWPs may be activated, and the UE may not assume that it will transmit or receive specific signals / channels other than the activated BWP.

[0366] The above-mentioned structures of radio frames, subframes, slots, mini-slots, and symbols are merely examples. For example, the number of subframes in a radio frame, the number of slots per subframe or radio frame, the number of mini-slots within a slot, the number of symbols and RBs within a slot or mini-slot, the number of subcarriers within an RB, the number of symbols within a TTI, the symbol length, and the cyclic prefix (CP) length can be modified in various ways.

[0367] Furthermore, the information and parameters described in this disclosure may be expressed as absolute values, relative values ​​relative to a specific value, or other corresponding information. For example, wireless resources may be indicated by specific indexes.

[0368] The names used for parameters, etc. in this disclosure are not intended to be limiting in any respect. Furthermore, the mathematical formulas used for these parameters may differ from those explicitly disclosed in this disclosure. Various channels (PUCCH, PDCCH, etc.) and information elements can be identified by any suitable names, and therefore the various names assigned to these various channels and information elements are not intended to be limiting in any respect.

[0369] Information, signals, and the like described in this disclosure may also be represented using any of a variety of different technologies. For example, data, instructions, commands, information, signals, bits, symbols, chips, and the like that may be referred to throughout the foregoing description may also be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or photons, or any combination thereof.

[0370] Furthermore, information, signals, etc. can be output in at least one of the following directions: from a higher layer (upper layer) to a lower layer (lower layer), and from a lower layer to a higher layer. Information, signals, etc. can also be input and output via multiple network nodes.

[0371] Input and output information, signals, etc. can be stored in a specific location (e.g., memory) or managed using a management table. Input and output information, signals, etc. can be overwritten, updated, or appended. Output information, signals, etc. can also be deleted. Input information, signals, etc. can also be sent to other devices.

[0372] The notification of information is not limited to the methods / implementations described in this disclosure and may also be performed using other methods. For example, the notification of information in this disclosure may also be implemented through physical layer signaling (e.g., downlink control information (Downlink Control Information (DCI)), uplink control information (Uplink Control Information (UCI))), higher layer signaling (e.g., Radio Resource Control (RRC) signaling, broadcast information (Master Information Block (MIB)), System Information Block (SIB), etc.), Medium Access Control (MAC) signaling), other signals, or a combination thereof.

[0373] Physical layer signaling may also be referred to as Layer 1 / Layer 2 (L1 / L2) control information (L1 / L2 control signal), Layer 1 control information (L1 control signal), etc. Furthermore, RRC signaling may also be referred to as an RRC message, such as an RRC Connection Setup message or an RRC Connection Reconfiguration message. Furthermore, MAC signaling may also be notified using, for example, a MAC Control Element (CE).

[0374] Furthermore, notification of specific information (eg, notification of “it is X”) is not limited to explicit notification, but may be performed implicitly (eg, by not notifying the specific information or by notifying other information).

[0375] The determination can be made using a value represented by a bit (0 or 1), a true or false value (Boolean value) represented by true or false, or a numerical comparison (eg, comparison with a specific value).

[0376] The term “software” or “firmware” shall be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, sub-programs, software modules, applications, software applications, software packages, routines, sub-routines, objects, executable files, execution threads, procedures, functions, etc.

[0377] Furthermore, software, instructions, information, and the like may also be transmitted and received via a transmission medium. For example, if the software is transmitted from a website, server, or other remote source using at least one of a wired technology (coaxial cable, fiber optic cable, twisted pair, Digital Subscriber Line (DSL), etc.) and a wireless technology (infrared, microwave, etc.), at least one of the wired technology and the wireless technology is included within the definition of a transmission medium.

[0378] The terms "system" and "network" used in this disclosure are interchangeable. "Network" may also refer to devices included in the network (eg, base stations).

[0379] In the present disclosure, terms such as "precoding", "precoder", "weight (precoding weight)", "Quasi-Co-Location (QCL))", "Transmission Configuration Indication state (TCI state)", "spatial relation", "spatial domain filter", "transmit power", "phase rotation", "antenna port", "antenna port group", "layer", "number of layers", "rank", "resource", "resource set", "resource group", "beam", "beam width", "beam angle", "antenna", "antenna element", and "panel" can be used interchangeably.

[0380] In this disclosure, terms such as "base station (BS)", "wireless base station", "fixed station", "NodeB", "eNB (eNodeB)", "gNB (gNodeB)", "access point", "transmission point (TP)", "reception point (RP)", "transmission / reception point (TRP))", "panel", "cell", "sector", "cell group", "carrier", and "component carrier" are used interchangeably. In some cases, a base station may be referred to as a macrocell, small cell, femtocell, or picocell.

[0381] A base station can accommodate one or more (for example, three) cells. When a base station accommodates multiple cells, the base station's overall coverage area can be divided into multiple smaller areas, each of which can be provided with communications services by a base station subsystem (for example, a small indoor base station (Remote Radio Head (RRH))). Terms such as "cell" or "sector" refer to a portion or the entire coverage area of ​​at least one of a base station and a base station subsystem providing communications services within that coverage area.

[0382] In the present disclosure, the base station sends information to the terminal, and this situation can also be rewritten as the base station instructing the terminal to control / operate based on the information.

[0383] In the present disclosure, terms such as “mobile station (MS)”, “user terminal”, “user device (UE)”, and “terminal” can be used interchangeably.

[0384] A mobile station may also be referred to as a subscriber station, mobile unit, subscriber unit, wireless unit, remote unit, mobile device, wireless device, wireless communication device, remote device, mobile subscriber station, access terminal, mobile terminal, wireless terminal, remote terminal, hand set, user agent, mobile client, client, or several other appropriate terms.

[0385] At least one of the base station and the mobile station may also be referred to as a transmitting device, a receiving device, a wireless communication device, etc. In addition, at least one of the base station and the mobile station may also be a device mounted on a moving object, a moving object body, etc.

[0386] The mobile body refers to a movable object, and the moving speed is arbitrary, including the case where the mobile body is stopped. The mobile body includes, for example, vehicles, transport vehicles, cars, automatic two-wheeled vehicles (motorcycles), bicycles, connected cars, loading shovels, bulldozers, wheel loaders, dump trucks, forklifts, trains, buses, trolleys, rickshaws, ships (ships and other watercraft), airplanes, rockets, artificial satellites, drones, multicopters, quadcopters, hot air balloons, and objects carried on them, but is not limited to these. In addition, the mobile body can also be a mobile body that moves autonomously based on operating instructions.

[0387] The mobile object may be a vehicle (e.g., a car, an aircraft, etc.), an unmanned mobile object (e.g., a drone, an autonomous vehicle, etc.), or a robot (manned or unmanned). Furthermore, at least one of the base station and the mobile station may include a device that does not necessarily move during communication operations. For example, at least one of the base station and the mobile station may be an Internet of Things (IoT) device such as a sensor.

[0388] Figure 18 This diagram shows an example of a vehicle according to one embodiment. Vehicle 40 includes a drive unit 41, a steering unit 42, an accelerator pedal 43, a brake pedal 44, a shift lever 45, left and right front wheels 46, left and right rear wheels 47, an axle 48, an electronic control unit 49, various sensors (including a current sensor 50, a rotation speed sensor 51, an air pressure sensor 52, a vehicle speed sensor 53, an acceleration sensor 54, an accelerator pedal sensor 55, a brake pedal sensor 56, a shift lever sensor 57, and an object detection sensor 58), an information service unit 59, and a communication module 60.

[0389] The drive unit 41 is composed of, for example, at least one of an engine, a motor, or a combination of an engine and a motor. The steering unit 42 is configured to include at least a steering wheel (also referred to as a handle), and steers at least one of the front wheels 46 and the rear wheels 47 based on the user's operation of the steering wheel.

[0390] The electronic control unit 49 is composed of a microprocessor 61, memory (ROM, RAM) 62, and communication ports (e.g., input / output (IO) ports) 63. Signals from various sensors 50-58 included in the vehicle are input to the electronic control unit 49. The electronic control unit 49 may also be referred to as an electronic control unit (ECU).

[0391] As signals from various sensors 50-58, there are current signals from the current sensor 50 that senses the current of the motor, speed signals of the front wheels 46 / rear wheels 47 obtained by the speed sensor 51, air pressure signals of the front wheels 46 / rear wheels 47 obtained by the air pressure sensor 52, vehicle speed signals obtained by the vehicle speed sensor 53, acceleration signals obtained by the acceleration sensor 54, depression amount signals of the accelerator pedal 43 obtained by the accelerator pedal sensor 55, depression amount signals of the brake pedal 44 obtained by the brake pedal sensor 56, operation signals of the shift lever 45 obtained by the shift lever sensor 57, detection signals for detecting obstacles, vehicles, pedestrians, etc. obtained by the object detection sensor 58, etc.

[0392] Information service unit 59 is comprised of various devices, such as a navigation system, audio system, speakers, display, television, and radio, that provide (output) various types of information, including driving information, traffic information, and entertainment information, and one or more ECUs that control these devices. Information service unit 59 uses information acquired from external devices via communication module 60 and the like to provide various information and services (e.g., multimedia information and multimedia services) to vehicle 40 occupants.

[0393] The information service unit 59 may include an input device for accepting input from the outside (e.g., a keyboard, a mouse, a microphone, a switch, a button, a sensor, a touch panel, etc.), or an output device for outputting to the outside (e.g., a display, a speaker, an LED light, a touch panel, etc.).

[0394] The driving assistance system unit 64 is composed of various devices that provide functions for preventing accidents or reducing the driver's driving burden, such as millimeter-wave radar, light detection and ranging (LiDAR), cameras, positioners (e.g., Global Navigation Satellite System (GNSS)), map information (e.g., High Definition (HD) maps, Autonomous Vehicle (AV) maps), gyroscope systems (e.g., inertial measurement units (IMUs)), inertial navigation systems (INS), artificial intelligence (AI) chips, and AI processors, as well as one or more ECUs that control these devices. Furthermore, the driving assistance system unit 64 transmits and receives various information via the communication module 60 to implement driving assistance functions or autonomous driving functions.

[0395] The communication module 60 can communicate with the microprocessor 61 and components of the vehicle 40 via the communication port 63. For example, the communication module 60 transmits and receives data (information) via the communication port 63 with the drive unit 41, steering unit 42, accelerator pedal 43, brake pedal 44, shift lever 45, left and right front wheels 46, left and right rear wheels 47, axle 48, the microprocessor 61 in the electronic control unit 49, the memory (ROM, RAM) 62, and various sensors 50-58 included in the vehicle 40.

[0396] The communication module 60 is controlled by the microprocessor 61 of the electronic control unit 49 and is a communication device capable of communicating with external devices. For example, various information can be transmitted and received with the external device via wireless communication. The communication module 60 can be located either inside or outside the electronic control unit 49. Examples of external devices include the aforementioned base station 10 and user terminal 20. Furthermore, the communication module 60 can also be, for example, at least one of the aforementioned base station 10 and user terminal 20 (or function as at least one of the base station 10 and user terminal 20).

[0397] The communication module 60 may also transmit at least one of the following to an external device via wireless communication: signals input to the electronic control unit 49 from the various sensors 50-58, information obtained based on these signals, and information based on external (user) input received via the information service unit 59. The electronic control unit 49, the various sensors 50-58, the information service unit 59, etc. may also be referred to as input units that receive input. For example, the PUSCH transmitted via the communication module 60 may also include information based on these inputs.

[0398] The communication module 60 receives various information (such as traffic information, traffic light information, and vehicle information) transmitted from external devices and displays it on the vehicle's information service unit 59. The information service unit 59 can also be referred to as an output unit that outputs information (for example, information output to a display, speaker, or other device based on the PDSCH received by the communication module 60 (or data / information decoded from the PDSCH)).

[0399] Furthermore, the communication module 60 stores various information received from external devices in a memory 62 that can be used by the microprocessor 61. Based on the information stored in the memory 62, the microprocessor 61 can also control the drive unit 41, steering unit 42, accelerator pedal 43, brake pedal 44, shift lever 45, left and right front wheels 46, left and right rear wheels 47, axles 48, various sensors 50-58, and the like included in the vehicle 40.

[0400] Furthermore, the base station in this disclosure can also be rewritten as a user terminal. For example, the various methods / implementations of this disclosure can also be applied to a structure in which communication between a base station and a user terminal is replaced by communication between multiple user terminals (e.g., device-to-device (D2D) or vehicle-to-everything (V2X)). In this case, the user terminal 20 can also have the functions of the base station 10 described above. Furthermore, terms such as "uplink" and "downlink" can also be rewritten with terms corresponding to inter-terminal communication (e.g., "sidelink"). For example, uplink channels, downlink channels, etc. can also be rewritten as sidelink channels.

[0401] Likewise, the user terminal in the present disclosure may be rewritten as a base station. In this case, the base station 10 may have the functions of the user terminal 20 described above.

[0402] In this disclosure, actions performed by a base station may also be performed by its upper node depending on the situation. Obviously, in a network including one or more network nodes including a base station, various operations performed for communication with a terminal may be performed by the base station, one or more network nodes other than the base station (for example, but not limited to, a Mobility Management Entity (MME) and a Serving-Gateway (S-GW)), or a combination thereof.

[0403] The various methods / implementations described in this disclosure may be used individually or in combination, and may be switched between them during execution. Furthermore, the processing procedures, timings, flow charts, and the like of the various methods / implementations described in this disclosure may be reversed as long as they do not conflict. For example, the methods described in this disclosure use an illustrative order to present elements of various steps, but are not limited to the specific order presented.

[0404] The various modes and embodiments described in the present disclosure may also be applied to Long Term Evolution (LTE), LTE-Advanced (LTE-A), LTE-Beyond (LTE-B), SUPER 3G, IMT-Advanced, 4th generation mobile communication system (4G), 5th generation mobile communication system (5G), 6th generation mobile communication system (6G), xth generation mobile communication system (xG (x is, for example, an integer or a decimal)), Future Radio Access (FRA), New Radio Access Technology (RAT), New Radio (NR), New Radio Access (NX), Future Generation Radio Access (FX), Global System for Mobile Communications (GSM (registered trademark)), CDMA2000, Ultra Mobile Broadband (UMB), IEEE IEEE 802.11 (Wi-Fi (registered trademark)), IEEE 802.16 (WiMAX (registered trademark)), IEEE 802.20, Ultra-WideBand (UWB), Bluetooth (registered trademark), systems utilizing other appropriate wireless communication methods, and next-generation systems based on these that are extended, modified, generated, or specified. Furthermore, multiple systems may be combined for application (for example, LTE or LTE-A combined with 5G).

[0405] The phrase “based on” used in this disclosure does not mean “based only on” unless otherwise specified. In other words, the phrase “based on” means both “based only on” and “based at least on.”

[0406] Any reference to an element using the designations "first," "second," etc., as used in this disclosure, does not necessarily define the quantity or order of these elements. These designations may be used in this disclosure as a convenient method of distinguishing between two or more elements. Therefore, reference to a first and a second element does not imply that only two elements may be used or that the first element must in some way take precedence over the second element.

[0407] The term "determining" as used in this disclosure may encompass a wide variety of actions. For example, "determining" may also encompass situations where judging, calculating, computing, processing, deriving, investigating, looking up (e.g., searching a table, database, or other data structure), ascertaining, and the like are considered "determining."

[0408] In addition, “judgment (decision)” may also refer to situations where receiving (e.g., receiving information), transmitting (e.g., sending information), input, output, accessing (e.g., accessing data in a memory), etc. are regarded as “judgment (decision)”.

[0409] Furthermore, "judgment (decision)" can also refer to situations where resolving, selecting, choosing, establishing, comparing, etc. can be considered "judgment (decision)". In other words, "judgment (decision)" can also refer to situations where certain actions can be considered "judgment (decision)".

[0410] Furthermore, in this disclosure, "determine / determining" can be interchanged with "assume / assuming," "expect / expecting," and "consider / considering." Furthermore, in this disclosure, "not assuming to proceed..." can be interchanged with "assuming not to proceed..."

[0411] The “maximum transmit power” described in the present disclosure may refer to the maximum value of the transmit power, the nominal UE maximum transmit power, or the rated UE maximum transmit power.

[0412] As used in this disclosure, the terms "connected," "coupled," or all variations thereof, refer to any direct or indirect connection or coupling between two or more elements, including the presence of one or more intermediate elements between the two elements being "connected" or "coupled." The coupling or connection between elements can be physical, logical, or a combination thereof. For example, "connected" can also be rephrased as "accessed."

[0413] In the present disclosure, when two elements are connected, it is possible to consider being "connected" or "combined" to each other using one or more wires, cables, printed electrical connections, etc., as well as using electromagnetic energy with wavelengths in the wireless frequency domain, microwave region, light (both visible and invisible) region, etc. as several non-limiting and non-inclusive examples to be "connected" or "combined" to each other.

[0414] In the present disclosure, the term "A is different from B" may also mean "A and B are different from each other." Alternatively, the term may also mean "A and B are each different from C." Terms such as "separate" and "bound" may also be interpreted in the same manner as "different."

[0415] When used in this disclosure, "include," "including," and variations thereof have the same inclusive meaning as the term "comprising." Furthermore, the term "or" used in this disclosure does not mean an exclusive OR.

[0416] In the present disclosure, when an article is added by translation, such as a, an, and the in English, the present disclosure may also include a case where the noun following the article is in a plural form.

[0417] In the present disclosure, "below," "less than," "above," "more than," "equal to," and the like may be replaced with one another. Furthermore, in the present disclosure, expressions meaning "good," "bad," "big," "small," "high," "low," "early," "late," "wide," and "narrow," etc., are not limited to the positive, comparative, and superlative forms, but may be replaced with one another. Furthermore, in the present disclosure, expressions meaning "good," "bad," "big," "small," "high," "low," "early," "late," "wide," and "narrow," etc., with "i" (where i is an arbitrary integer) are not limited to the positive, comparative, and superlative forms, but may be replaced with one another (for example, "highest" and "i-th highest" may be replaced with one another).

[0418] In the present disclosure, “of,” “for,” “regarding,” “related to,” “associated with,” etc. may also be replaced with each other.

[0419] While the invention disclosed herein has been described in detail above, it will be apparent to those skilled in the art that the invention disclosed herein is not limited to the embodiments described herein. The invention disclosed herein can be implemented in modified and altered forms without departing from the spirit and scope of the invention as defined by the claims. Therefore, the description herein is for illustrative purposes only and is not intended to limit the invention disclosed herein in any way.

Claims

1. A terminal comprising: a control unit that measures synchronization signal blocks (SSBs) corresponding to a set of multiple beams in each layer, and determines an index of an optimal beam based on the measurement result; and The transmitting unit transmits a physical random access channel (PRACH) corresponding to the index of the best beam.

2. The terminal according to claim 1, wherein: The control unit compares the reception powers of the plurality of SSBs in the layer, and determines the index of the optimal beam based on the SSB having the highest reception power in each layer.

3. The terminal according to claim 1, wherein: The receiving unit receives each beam included in the set of the plurality of beams, The control unit detects the path loss of each beam. The terminal according to claim 1 , wherein: The index of the optimal beam is used as the QCL source.

5. A wireless communication method, which is a wireless communication method of a terminal, comprising: a step of measuring synchronization signal blocks (SSBs) corresponding to a set of multiple beams of each layer, and determining an index of an optimal beam based on the measurement result; and The step of sending a physical random access channel PRACH corresponding to the index of the best beam.

6. A base station comprising: a control unit that controls transmission of a synchronization signal block (SSB) corresponding to a set of a plurality of beams of each layer; and The receiving unit receives a physical random access channel PRACH corresponding to the index of the best beam determined based on the measurement result of the SSB.

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