Terminal, wireless communication method, base station and system

Abstract

A terminal according to an aspect of the present disclosure includes: a control unit that determines one transmission scheme from among a first transmission scheme of transmitting a physical random access channel (PRACH) accompanied by a plurality of repetitions, a second transmission scheme of transmitting the plurality of repetitions using the same beam, a third transmission scheme of transmitting the a plurality of repetitions using a plurality of different beams, and a fourth transmission scheme of transmitting the a plurality of repetitions using the same beam and a plurality of different beams; and a transmission unit that uses said transmission scheme to transmit one or more PRACHs. According to the aspect of the present disclosure, the coverage of a random access procedure can be improved.

Description

Terminal, wireless communication method and base station

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

[0002] Long Term Evolution (LTE) has been specified for the Universal Mobile Telecommunications System (UMTS) network with the aim of achieving higher data rates and lower latency (Non-Patent Document 1). Also, LTE-Advanced (3GPP Rel. 10-14) has been specified with the aim of achieving higher capacity and more advanced features than LTE (Third Generation Partnership Project (3GPP (registered trademark)) Release (Rel.) 8, 9).

[0003] Successor systems to LTE (e.g., 5th generation mobile communication system (5G), 5G+ (plus), 6th generation mobile communication system (6G), New Radio (NR), 3GPP Rel. 15 or later, etc.) are also being considered.

[0004] 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

[0005] Improvements in coverage are being considered for future wireless communication systems (e.g., NR).

[0006] However, the random access procedure for improving coverage is not clear, and if such a random access procedure is not clear, communication throughput may decrease.

[0007] Therefore, one of the objects of the present disclosure is to provide a terminal, a wireless communication method, and a base station that improve the coverage of the random access procedure.

[0008] A terminal according to one aspect of the present disclosure has a control unit that determines one of a first transmission scheme for transmitting a physical random access channel (PRACH) without multiple repetitions, a second transmission scheme for transmitting the multiple repetitions using the same beam, a third transmission scheme for transmitting the multiple repetitions using different beams, and a fourth transmission scheme for transmitting the multiple repetitions using the same beam and different beams, and a transmission unit that transmits one or more PRACHs using the transmission schemes.

[0009] According to one aspect of the present disclosure, the coverage of the random access procedure can be improved.

[0010] FIG. 1 shows an example of a RACH configuration information element. FIGS. 2A and 2B show an example of PRACH repetition with the same beam. FIGS. 3A and 3B show an example of PRACH repetition with different beams. FIGS. 4A and 4B show an example of operations allowed in Option 4 / Option 3. FIGS. 5A and 5B show an example of Options 3-8. FIG. 6 shows a first example of the operation of Operation A / C of Options 4-8. FIG. 7 shows a second example of the operation of Operation A / C of Options 4-8. FIG. 8 shows a third example of the operation of Operation A / C of Options 4-8. FIG. 9 shows a fourth example of the operation of Operation A / C of Options 4-8. FIG. 10 shows a first example of the operation of Operation B / D of Options 4-8. FIG. 11 shows a second example of the operation of Operation B / D of Options 4-8. FIG. 12 is a diagram showing an example of a schematic configuration of a wireless communication system according to an embodiment. FIG. 13 is a diagram showing an example of the configuration of a base station according to an embodiment. FIG. 14 is a diagram showing an example of the configuration of a user terminal according to an embodiment. Fig. 15 is a diagram illustrating an example of a hardware configuration of a base station and a user terminal according to an embodiment. Fig. 16 is a diagram illustrating an example of a vehicle according to an embodiment.

[0011] (TCI, spatial relationship, QCL) In NR, it is considered 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 encoding) in a UE of at least one of a signal and a channel (referred to as a signal / channel) based on a transmission configuration indication state (TCI state).

[0012] The TCI state may represent that which is applied to a downlink signal / channel, and the equivalent of the TCI state that is applied to an uplink signal / channel may be expressed as a spatial relation.

[0013] The TCI state is information about the Quasi-Co-Location (QCL) of signals / channels, and may also be called spatial reception parameters, spatial relation information, etc. The TCI state may be configured in the UE for each channel or signal.

[0014] The QCL is an index indicating the statistical properties of signals / channels. For example, if a signal / channel has a QCL relationship with another signal / channel, it may mean that it can be assumed that at least one of a Doppler shift, a Doppler spread, an average delay, a delay spread, and a spatial parameter (e.g., a spatial Rx parameter) is the same between these different signals / channels (i.e., the signals / channels have a QCL with respect to at least one of these).

[0015] The spatial reception parameters may correspond to a reception beam (e.g., a reception analog beam) of the UE, and the beam may be identified based on a spatial QCL. The QCL (or at least one element of the QCL) in the present disclosure may be replaced with sQCL (spatial QCL).

[0016] A plurality of types (QCL types) of QCL may be defined. For example, four QCL types A to D may be provided, each having different parameters (or parameter sets) that can be assumed to be the same. The parameters (which may be referred to as QCL parameters) are as follows: QCL type A (QCL-A): Doppler shift, Doppler spread, mean delay, and delay spread QCL type B (QCL-B): Doppler shift and Doppler spread QCL type C (QCL-C): Doppler shift and mean delay QCL type D (QCL-D): Spatial reception parameters.

[0017] The UE's assumption that a Control Resource Set (CORESET), channel, or reference signal has a specific QCL (e.g., QCL type D) relationship with another CORESET, channel, or reference signal may be referred to as a QCL assumption.

[0018] The UE may determine at least one of a transmit beam (Tx beam) and a receive beam (Rx beam) for a signal / channel based on the TCI condition or QCL assumption of the signal / channel.

[0019] The TCI state may be, for example, information about the QCL between the channel of interest (in other words, the Reference Signal (RS) for that channel) and another signal (e.g., another RS). The TCI state may be set (indicated) by higher layer signaling, physical layer signaling, or a combination thereof.

[0020] The physical layer signaling may be, for example, Downlink Control Information (DCI).

[0021] 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)).

[0022] Furthermore, the RS that has a QCL relationship with the channel may be, for example, at least one of a synchronization signal block (SSB), a channel state information reference signal (CSI-RS), a sounding reference signal (SRS), a tracking CSI-RS (also called a tracking reference signal (TRS)), and a QCL detection reference signal (also called a QRS).

[0023] An SSB is a signal block including at least one of a Primary Synchronization Signal (PSS), a Secondary Synchronization Signal (SSS), and a Physical Broadcast Channel (PBCH). An SSB may also be referred to as an SS / PBCH block.

[0024] An RS of QCL type X in a TCI state may refer to an RS that has a QCL type X relationship with a certain channel / signal (DMRS), and this RS may be called a QCL source of QCL type X in the TCI state.

[0025] (Initial Access Procedure) In the initial access procedure, a UE (RRC_IDLE mode) receives an SS / PBCH block (SSB), transmits Msg. 1 (PRACH / random access preamble / preamble), receives Msg. 2 (PDCCH, PDSCH including random access response (RAR)), transmits Msg. 3 (PUSCH scheduled by RAR UL grant), and receives Msg. 4 (PDCCH, PDSCH including UE contention resolution identity). After that, when an ACK for Msg. 4 is transmitted from the UE by the base station (network), an RRC connection is established (RRC_CONNECTED mode).

[0026] SSB reception includes PSS detection, SSS detection, PBCH-DMRS detection, and PBCH reception. PSS detection includes detecting part of the physical cell ID (PCI), detecting (synchronizing) OFDM symbol timing, and (coarse) frequency synchronization. SSS detection includes detecting the physical cell ID. PBCH-DMRS detection includes detecting (part of) the SSB index within a half radio frame (5 ms). PBCH reception includes detecting the system frame number (SFN) and radio frame timing (SSB index), receiving configuration information for receiving remaining minimum system information (RMSI, SIB1), and recognizing whether the UE can camp on that cell (carrier).

[0027] SSB has a bandwidth of 20 RBs and a time of 4 symbols. The transmission period of SSB can be set to {5, 10, 20, 40, 80, 160} ms. In a half frame, multiple symbol positions of SSB are defined based on the frequency range (FR1, FR2).

[0028] The PBCH has a payload of 56 bits. N repetitions of the PBCH are transmitted within a period of 80 ms, where N depends on the SSB transmission period.

[0029] The system information consists of the MIB, RMSI (SIB1), and other system information (OSI) carried by the PBCH. SIB1 contains information for RACH setup and RACH procedures. The time / frequency resource relationship between the SSB and the PDCCH monitoring resource for SIB1 is configured by the PBCH.

[0030] A base station using beam correspondence transmits multiple SSBs using multiple beams for each SSB transmission period. The multiple SSBs have multiple SSB indices, respectively. When a UE detects an SSB, it transmits a PRACH in the RACH occasion associated with that SSB index and receives an RAR in the RAR window.

[0031] (Beams and Coverage) In high frequency bands, if beamforming is not applied to synchronization signals / reference signals, coverage will be narrow, making it difficult for UEs to find base stations. On the other hand, if beamforming is applied to synchronization signals / reference signals to ensure coverage, a strong signal will reach a specific direction, but the signal will be even less likely to reach other directions. If the base station does not know the direction in which the UE is located before the UE connects, it is impossible to transmit synchronization signals / reference signals using beams pointing only in the appropriate direction. One possible method is for the base station to transmit multiple synchronization signals / reference signals, each with a beam pointing in a different direction, and for the UE to recognize which beam it has found. Using thin (narrow) beams for coverage requires transmitting many synchronization signals / reference signals, which may increase overhead and reduce frequency utilization efficiency.

[0032] In order to reduce the number of beams (synchronization signals / reference signals) and reduce overhead, using thick (wide) beams results in narrower coverage.

[0033] In future wireless communication systems (e.g., 6G), it is expected that frequency bands such as millimeter waves and terahertz waves will be used more widely. Communication services will be provided by building cell areas / coverages using multiple narrow beams.

[0034] It is possible to expand the coverage area by using the existing FR2 and to use a higher frequency band than the existing FR2. To achieve these, it is desirable to improve beam management in addition to multi-TRP, reconfigurable intelligent surface (RIS), etc.

[0035] Coverage extensions are being considered, including PRACH extensions for frequency range (FR) 2. For example, PRACH repetition using the same beam or different beams is being considered. This PRACH extension may also be applied to FR1.

[0036] The PRACH extension may be applied to the short PRACH format or to other formats.

[0037] As shown in Figure 1, the common RACH configuration (RACH-ConfigCommon) may include a generic RACH configuration (rach-ConfigGeneric), a total number of RA preambles (totalNumberOfRA-Preambles), and SSB per RACH occasion and contention-based (CB) preambles per SSB (ssb-perRACH-OccasionAndCB-PreamblesPerSSB). rach-ConfigGeneric may include a PRACH configuration index (prach-ConfigurationIndex) and message 1 FDM (msg1-FDM, the number of PRACH occasions FDMed in one time instance). ssb-perRACH-OccasionAndCB-PreamblesPerSSB may contain the number of CB preambles per SSB for oneEighth (one SSB associated with eight RACH occasions) SSBs per RACH occasion.

[0038] For a Type 1 random access procedure (four-step random access procedure, messages 1 / 2 / 3 / 4), the UE may specify the number N of SS / PBCH blocks associated with one PRACH occasion and the number R of CB preambles per SS / PBCH block per valid PRACH occasion via ssb-perRACH-OccasionAndCB-PreamblesPerSSB.

[0039] For a Type 1 random access procedure, or for a Type 2 random access procedure with PRACH occasion configuration independent of the Type 1 random access procedure (two-step random access procedure, message A / B), if N<1, one SS / PBCH block is mapped to 1 / N consecutive valid RACH occasions, and for each valid PRACH occasion, R CB preambles with consecutive indices associated with the SS / PBCH block index are mapped, starting with preamble index 0. If N>=1, R CB preambles with consecutive indices associated with the SS / PBCH block index n (0<=n<-N-1) are mapped, starting with preamble index n·N_preamble^total / N. where N_preamble^total is given by totalNumberOfRA-Preambles for a Type 1 random access procedure and by msgA-TotalNumberOfRA-Preambles for a Type 2 random access procedure that involves the configuration of a PRACH occasion independent of the Type 1 random access procedure, and N_preamble^total is a multiple of N.

[0040] Starting from frame 0, the association period for mapping SS / PBCH blocks to PRACH occasions is the smallest value in the set determined by the PRACH configuration period according to the relationship (defined in the specification) between the PRACH configuration period and the association period (number of PRACH configuration periods) such that N_Tx^SSB SS / PBCH block indices are mapped to a PRACH occasion at least once within that association period, where the UE derives N_Tx^SSB from the value of SSB-PositionsInBurst in SIB1 or in the common serving cell configuration (ServingCellConfigCommon). If there is a set of PRACH occasions or PRACH preambles that are not mapped to N_Tx^SSB SS / PBCH block indices after an integer number of mapping cycles from SS / PBCH block indices to PRACH occasions within an association period, then no SS / PBCH block index is mapped to that set of PRACH occasions or PRACH preambles. An association pattern period includes one or more association periods and is determined such that the pattern between PRACH occasions and SS / PBCH block indices repeats at most every 160 ms. If there is a PRACH occasion that is not associated with an SS / PBCH block index after an integer number of association periods, that PRACH occasion is not used for PRACH.

[0041] For PRACH configuration periods of 10, 20, 40, 80, and 160 msec, the association periods are {1, 2, 4, 8, 16}, {1, 2, 4, 8}, {1, 2, 4}, {1, 2}, and {1}, respectively.

[0042] For the association of PRACH occasions (RACH occasions (ROs)) and beams (SSBs / CSI-RSs), if ssb-perRACH-OccasionAndCB-PreamblesPerSSB indicates oneHalf,n16 (N=½, R=16) and msg1-FDM is 4, four ROs are FDM-multiplexed in one time instance, and one SSB is mapped to two ROs. Preamble indexes 0 to 15 are associated with two ROs, and preamble indexes 0 to 15 are associated with SS0B. In this way, when N<1, one SSB is mapped to multiple ROs. This increases the RO capacity per beam.

[0043] If ssb-perRACH-OccasionAndCB-PreamblesPerSSB indicates n4,n16 (N=4, R=16), msg1-FDM is 4, and N_preamble^total is 64, four ROs are FDM-modulated in one time instance, and four SSBs are mapped to one RO. One RO is associated with SSBs 0 to 3. Preamble indices 0 to 15 are associated with SSB 0, preamble indices 15 to 31 are associated with SSB 1, preamble indices 32 to 47 are associated with SSB 2, and preamble indices 48 to 63 are associated with SSB 3. In this way, the same RO is associated with different SS / PBCH block indices, and different preambles use different SS / PBCH block indices. The base station can distinguish the associated SS / PBCH block indices based on the received PRACH.

[0044] The random access preamble can only be transmitted in the time resources specified in the random access configuration of the specification, which depends on whether FR1 or FR2 is used and the spectrum type (paired spectrum / supplementary uplink (SUL) / unpaired spectrum). The PRACH configuration index is given by the higher layer parameter prach-ConfigurationIndex or, if configured, by msgA-PRACH-ConfigurationIndex. In the specification, each value of the PRACH configuration index is associated with at least one of the following: preamble format, x and y in n_f (frame number) mod x = y, subframe number, starting symbol, number of PRACH slots in a subframe, number of time-domain PRACH occasions in a PRACH slot N_t^RA,slot, and PRACH duration N_dur^RA.

[0045] Depending on whether PRACH repetition is applicable to a scenario, different types of RACH procedures may be triggered for different purposes. The type of RACH procedure may be at least one of the following: contention-free random access (CFRA), PDCCH ordered RA (RA initiated by a PDCCH order), CFRA for beam failure recovery (BFR), CFRA for system information (SI) request, CFRA for reconfiguration with sync, etc.; contention-based random access (CBRA), RA triggered by a MAC entity, RA triggered by an RRC with an event, CBRA for BFR, etc.; four-step RACH; two-step RACH.

[0046] However, the configuration / procedure of PRACH repetition is unclear. For example, it is unclear how PRACH resources for repetition (e.g., repetition pattern, number of repetitions) are configured, the UE operation of preamble repetition transmission, the impact on counters / timers related to the RACH, etc. If such configuration / procedure is unclear, there is a risk of degradation in communication quality / communication throughput.

[0047] (RA Response Window) The RA Response Window (ra-ResponseWindow) is the time window for monitoring the RA Response (RAR) (special cell (SpCell) only). The RA Contention Resolution Timer (ra-ContentionResolutionTimer) is the timer for RA contention resolution (SpCell only). The Msg. B Response Window is the time window for monitoring the RA Response (RAR) for the 2-step RA type (SpCell only).

[0048] In the present disclosure, SpCell, primary cell (PCell), and primary secondary cell (PSCell) may be read as interchangeable.

[0049] Once the RA preamble is transmitted, the MAC entity performs the following actions 1 to 3, regardless of whether a measurement gap may occur.

[0050] [Operation 1] If a contention-free RA preamble for a BFR request is transmitted by the MAC entity, the MAC entity performs the following operations 1-1 and 1-2. [[Operation 1-1]] The MAC entity starts the ra-ResponseWindow set in the BFR configuration (BeamFailureRecoveryConfig) on ​​the first PDCCH occasion after the end of the RA preamble transmission. [[Operation 1-2]] While the ra-ResponseWindow is running, the MAC entity monitors PDCCH transmissions in the search space indicated by the BFR search space ID (recoverySearchSpaceId) of the SpCell identified by its C-radio network temporary identifier (RNTI).

[0051] [Operation 2] Otherwise, the MAC entity performs the following operations 2-1 and 2-2. [[Operation 2-1]] The MAC entity starts the ra-ResponseWindow configured in the common RACH configuration (RACH-ConfigCommon) on the first PDCCH occasion after the end of the RA preamble transmission. [[Operation 2-2]] The MAC entity monitors the PDCCH transmission of the SpCell for the RAR identified by the RA-RNTI while the ra-ResponseWindow is running.

[0052] [Action 3] If the ra-ResponseWindow configured in BeamFailureRecoveryConfig expires and a PDCCH transmission on the search space indicated by recoverySearchSpaceId addressed to the C-RNTI is received on the serving cell on which the preamble was transmitted, or if the ra-ResponseWindow configured in RACH-ConfigCommon expires and an RAR is received containing RA preamble identifiers matching the transmitted preamble index (PREAMBLE_INDEX), the MAC entity considers the RAR reception as a failure and increments the preamble transmission counter (PREAMBLE_TRANSMISSION_COUNTER) by 1.

[0053] The MAC entity may stop the ra-ResponseWindow (stop monitoring for RARs) after successful reception of an RAR containing RA preamble identifiers matching the transmitted PREAMBLE_INDEX.

[0054] For PDCCH monitoring within the RA response window, there are two cases: PDCCH for the base station's response to BFR and PDCCH for RAR. The following may apply to both cases.

[0055] Once the MSGA (Msg. A) preamble is transmitted, the MAC entity performs the following actions 4 to 6, regardless of whether a measurement gap may occur.

[0056] [Action 4] The MAC entity starts the Msg. B response window (msgB-ResponseWindow) in the PDCCH monitoring window defined in the specification.

[0057] The msgB-ResponseWindow may start at the first symbol of the earliest CORESET for which the UE is configured to receive PDCCH for a Type 1-PDCCH CSS set that is at least one symbol after the last symbol of the PRACH occasion corresponding to the PRACH transmission. The length of the msgB-ResponseWindow may correspond to the SCS for the Type 1-PDCCH CSS set.

[0058] [Action 5] The MAC entity monitors the PDCCH transmission of the SpCell for the RAR identified by the MSGB-RNTI while the msgB-ResponseWindow is running.

[0059] [Action 6] If a C-RNTI MAC CE is included in the MSGA, the MAC entity monitors the PDCCH transmission of the SpCell for RAR identified by the C-RNTI while the msgB-ResponseWindow is running.

[0060] The RA-RNTI associated with the PRACH occasion on which the RA preamble is transmitted is calculated as follows: RA-RNTI = 1 + s_id + 14 × t_id + 14 × 80 × f_id + 14 × 80 × 8 × ul_carrier_id

[0061] where s_id is the index of the first OFDM symbol of the PRACH occasion (0<=s_id<14). t_id is the index of the first slot of the PRACH occasion within the system frame (0<=t_id<80). The subcarrier spacing (SCS) for determining t_id is based on the value of μ. f_id is the index of the PRACH occasion in the frequency domain (0<=f_id<8). ul_carrier_id is the UL carrier used for RA preamble transmission (0 for normal uplink (NUL) carrier, 1 for supplementary uplink (SUL) carrier). The RA-RNTI is calculated according to the specification. RA-RNTI is the RNTI for a 4-step RACH.

[0062] The MSGB-RNTI associated with the PRACH occasion on which the RA preamble is transmitted is calculated as follows: MSGB-RNTI = 1 + s_id + 14 × t_id + 14 × 80 × f_id + 14 × 80 × 8 × ul_carrier_id + 14 × 80 × 8 × 2

[0063] where s_id is the index of the first OFDM symbol of the PRACH occasion (0<=s_id<14). t_id is the index of the first slot of the PRACH occasion within the system frame (0<=t_id<80). The subcarrier spacing (SCS) for determining t_id is based on the value of μ. f_id is the index of the PRACH occasion in the frequency domain (0<=f_id<8). ul_carrier_id is the UL carrier used for RA preamble transmission (0 for normal uplink (NUL) carrier, 1 for supplementary uplink (SUL) carrier). MSGB-RNTI is the RNTI for the two-step RACH.

[0064] (PDCCH Order) <DCI Format for PDCCH Order> DCI format 1_0 includes a DCI format identifier field, a bit field that is always set to 1, and a frequency domain resource assignment field. If the cyclic redundancy check (CRC) of DCI format 1_0 is scrambled by the C-RNTI and the frequency domain resource assignment field is all 1, then DCI format 1_0 is for a random access procedure initiated by a PDCCH order, and the remaining fields are a random access preamble, a UL / supplementary uplink (SUL) indicator, a SS / PBCH index (SSB index), a PRACH mask index, and reserved bits (12 bits).

[0065] <PRACH Occasion> For a PRACH transmission triggered by a PDCCH order, the PRACH Mask Index field indicates the PRACH occasion of the PRACH transmission associated with the SS / PBCH block index indicated by the SS / PBCH Block Index field of the PDCCH order if the value of the Random Access Preamble Index field is not zero.

[0066] For PRACH transmissions triggered by higher layers (PRACH transmissions not triggered by a PDCCH order), if ssb-ResourceList is provided, the PRACH mask index is indicated by ra-ssb-OccasionMaskIndex, which indicates the PRACH occasion for the PRACH transmission associated with the selected SS / PBCH block index.

[0067] PRACH occasions are mapped consecutively for each corresponding SS / PBCH block index. The indexing of PRACH occasions indicated by the mask index value is reset for each SS / PBCH block index and for each successive PRACH occasion mapping cycle. In the first available mapping cycle, the UE selects for PRACH transmission the PRACH occasion indicated by the PRACH mask index value for the indicated SS / PBCH block index.

[0068] For a given preamble index, the ordering of PRACH occasions is as follows: First, by increasing frequency resource index for frequency multiplexed PRACH occasions; Second, by increasing time resource index for time multiplexed PRACH occasions within a PRACH slot; Third, by increasing PRACH slot index.

[0069] For PRACH transmissions triggered upon request from higher layers, if csirs-ResourceList is provided, the value of ra-OccasionList indicates a list of PRACH occasions for the PRACH transmission, where the PRACH occasions are associated with the selected CSI-RS index indicated by csi-RS. The indexing of the PRACH occasions indicated by ra-OccasionList is reset every association pattern period.

[0070] The value of the PRACH mask index value (msgA-SSB-SharedRO-MaskIndex) is associated with the allowed PRACH occasions (PRACH occasion index values) of the SSB.

[0071] Random Access Procedure in the MAC Entity The random access procedure is initiated by a PDCCH order, by the MAC entity itself, or by RRC for specification-compliant events. Within a MAC entity, there can only be one random access procedure in progress at any given time. The random access procedure for an SCell is only initiated by a PDCCH order with ra-PreambleIndex different from 0b000000.

[0072] When a random access procedure is initiated on the serving cell, the MAC entity shall: set RA_TYPE to 4-stepRA if the random access procedure is initiated by a PDCCH order and the ra-PreambleIndex explicitly provided by the PDCCH is not 0b000000, or if the random access procedure is initiated due to a reconfiguration with synchronization and a contention-free random access resource of type 4-step RA is explicitly provided by rach-ConfigDedicated for the BWP selected for the random access procedure.

[0073] If the selected RA_TYPE is set to 4-step RA, the MAC entity shall: - If ra-PreambleIndex is explicitly provided by the PDCCH and ra-PreambleIndex is not 0b000000, set PREAMBLE_INDEX to the signaled ra-PreambleIndex and select the SSB signaled by the PDCCH. - If an SSB is selected as above, determine the next available PRACH occasion from the PRACH occasions allowed by the restriction given by ra-ssb-OccasionMaskIndex and corresponding to the selected SSB. (The MAC entity selects a PRACH occasion randomly with equal probability from consecutive PRACH occasions corresponding to the selected SSB according to the specification. The MAC entity may take into account the possibility of measurement gaps when determining the next available PRACH occasion corresponding to the selected SSB.)

[0074] <Time Between PDCCH Order Reception and PRACH Transmission> If the random access procedure is initiated by a PDCCH order, the UE, if requested by higher layers, transmits the PRACH within the selected PRACH occasion if the time between the last symbol of the PDCCH order reception and the first symbol of the PRACH transmission is greater than or equal to N_(T,2) + Δ_BWPSwitching + Δ_Delay + T_switch [msec] (time condition), as described in the specification. Here, N_(T,2) is the duration of N_2 symbols corresponding to the PUSCH preparation time for UE processing capability 1. Assume that μ corresponds to the minimum subcarrier spacing (SCS) setting between the SCS setting of the PDCCH order and the SCS setting of the corresponding PRACH transmission. If the active UL BWP remains unchanged, Δ_BWPSwitching = 0; otherwise, Δ_BWPSwitching is defined in the specification. In FR1, Δ_delay=0.5 msec, and in FR2, Δ_delay=0.25 msec. T_switch is the switching gap duration defined in the specification.

[0075] <Valid / Invalid Conditions for PRACH Occasions> In paired spectrum (FDD) or SUL band, all PRACH occasions are valid. In unpaired spectrum (TDD), PRACH occasions may comply with the following provisions 1 and 2. [Provision 1] If the UE is not provided with tdd-UL-DL-Configuration Common, a PRACH occasion in a PRACH slot is valid if it does not precede an SS / PBCH block in the PRACH slot and starts at least N_gap symbols after the last SS / PBCH block received symbol. Here, N_gap is specified in the specifications. If channelAccessMode=semistatic is provided, the PRACH occasion does not overlap with the set of consecutive symbols before the start of the next channel occupation period in which the UE does not transmit. The candidate SS / PBCH block index of an SS / PBCH block corresponds to the SS / PBCH block index provided by ssb-PositionsInBurst in SIB1 or in ServingCellConfigCommon. [Provision 2] If the UE is provided with tdd-UL-DL-ConfigurationCommon, a PRACH occasion in a PRACH slot is valid if: - the PRACH occasion is in an UL symbol, or - the PRACH occasion does not precede an SS / PBCH block in the PRACH slot and starts at least N_gap symbols after the last DL symbol and at least N_gap symbols after the last SS / PBCH block symbol, where N_gap is specified in the specification. If channelAccessMode=semistatic is provided, the PRACH occasion does not overlap with the set of consecutive symbols before the start of the next channel occupation period during which there must be no transmission, as described in the specification.The candidate SS / PBCH block indices for the SS / PBCH blocks correspond to the SS / PBCH block indices provided by ssb-PositionsInBurst in SIB1 or in ServingCellConfigCommon as described in the specification.

[0076] (RAR Reception) In response to a PRACH transmission, the UE attempts to detect DCI format 1_0 with CRC scrambled by the corresponding RA-RNTI within the window controlled by the aforementioned higher layers. The window starts at the first symbol of the earliest CORESET for which the UE is configured to receive a PDCCH for the Type 1-PDCCH CSS set, i.e., at least one symbol after the last symbol of the PRACH occasion corresponding to the PRACH transmission. The symbol period corresponds to the SCS for the Type 1-PDCCH CSS set. The length of the window, based on the SCS for the Type 1-PDCCH CSS set, is given by the ra-responseWindow as the number of slots.

[0077] If a UE detects DCI format 1_0 with a CRC scrambled by the corresponding RA-RNTI and with least significant bits (LSBs) of the system frame number (SFN) field in that DCI format that are the same as the LSBs of the SFN with which the UE transmitted the PRACH, and the UE receives a transport block in the corresponding PDSCH, the UE may assume the same DMRS antenna port QCL properties for the SS / PBCH block or CSI-RS resource that the UE uses to associate the PRACH, regardless of whether the UE is provided with a TCI-State for the CORESET with which it receives the PDCCH with that DCI format 1_0.

[0078] If a UE attempts to detect DCI format 1_0 with CRC scrambled by the corresponding RA-RNTI in response to a PRACH transmission initiated by a PDCCH order that triggers a CFRA procedure for the SpCell, the UE may assume that the PDCCH containing that DCI format 1_0 and the PDCCH order have the same DMRS antenna port QCL properties. If a UE attempts to detect DCI format 1_0 with CRC scrambled by the corresponding RA-RNTI in response to a PRACH transmission initiated by a PDCCH order that triggers a CFRA procedure for the secondary cell, the UE may assume the DMRS antenna port QCL properties of the CORESET associated with the Type 1-PDCCH CSS set for reception of the PDCCH containing that DCI format 1_0.

[0079] The RAR UL grant may include at least one of a frequency hopping flag field, a PUSCH frequency resource allocation field, a PUSCH time resource allocation field, a modulation and coding scheme (MCS) field, a TPC command field for PUSCH, a CSI request field, and a channel access-cyclic prefix extension (CPext) field.

[0080] (PRACH Uplink Coverage Improvement) The following two cases / types of multi-PRACH transmission are being considered:

[0081] Case 1 / Type 1 Multi-PRACH Transmission: The UE repeatedly transmits Msg1 on n Random Access Occasions (ROs) / RO resources. The UE then waits to detect Msg2 on the configured Type 1 PDCCH occasion. In this disclosure, the repeated transmission of the preamble on n ROs / RO resources may be referred to as an RO group. The size of the RO group (the number of ROs in the RO group) is n. After one RO group, one RAR window begins.

[0082] Case 2 / Type 2 Multi-PRACH Transmission: The UE repeatedly transmits Msg1 on n Random Access Occasion (RO) resources. After transmitting Msg1 on each RO, the UE waits to detect Msg2 on a Type 1 PDCCH occasion. The size of the RO group (the number of ROs in the RO group) is n. After each RO, one RAR window starts.

[0083] (Beams Used for PRACH Repetition) In Rel. 18, it is being considered to introduce a function for PRACH repetition involving the same beam and a function for PRACH repetition involving multiple different beams. Figure 2A shows an example of a case where one RAR window is used for multiple PRACH repetitions using the same beam (Type 1 multi-PRACH transmission). Figure 2B shows an example of a case where multiple RAR windows are used for multiple PRACH repetitions using the same beam (Type 2 multi-PRACH transmission). Figure 3A shows an example of a case where one RAR window is used for multiple PRACH repetitions using multiple different beams (Type 1 multi-PRACH transmission). Figure 3B shows an example of a case where multiple RAR windows are used for multiple PRACH repetitions using multiple different beams (Type 2 multi-PRACH transmission).

[0084] However, the relationship / combination / interaction between the two functions is unclear. For example, it is unclear whether the two functions can be supported / applied simultaneously. If the two functions are not supported / applied simultaneously, it is unclear how the UE determines whether to transmit PRACH repetitions using the same beam, transmit PRACH repetitions using different beams, or perform no PRACH repetitions. If the two functions are supported / applied simultaneously, it is unclear when the UE applies the two functions simultaneously. As such, if the relationship between the two functions is unclear, it may result in degradation of communication quality, etc.

[0085] Therefore, the inventors came up with the idea of ​​a relationship between the function of PRACH repetition involving the same beam and the function of PRACH repetition involving multiple different beams.

[0086] Hereinafter, embodiments according to the present disclosure will be described in detail with reference to the drawings. Wireless communication methods according to the embodiments may be applied independently or in combination.

[0087] In the present disclosure, "A / B" and "at least one of A and B" may be interpreted interchangeably. Also, in the present disclosure, "A / B / C" may mean "at least one of A, B, and C."

[0088] In the present disclosure, terms such as notify, activate, deactivate, indicate (or indicate), select, configure, update, and determine may be read interchangeably. In the present disclosure, terms such as support, control, controllable, operate, and operate may be read interchangeably.

[0089] In the present disclosure, Radio Resource Control (RRC), RRC parameters, RRC messages, higher layer parameters, fields, information elements (IEs), settings, etc. may be interchangeable. In the present disclosure, Medium Access Control (MAC) control elements (CEs), update commands, activation / deactivation commands, etc. may be interchangeable.

[0090] In the present disclosure, higher layer signaling may be, for example, any one of Radio Resource Control (RRC) signaling, Medium Access Control (MAC) signaling, broadcast information, etc., or a combination thereof.

[0091] In the present disclosure, MAC signaling may use, for example, a MAC Control Element (MAC CE), a MAC Protocol Data Unit (PDU), etc. Broadcast information may be, for example, a Master Information Block (MIB), a System Information Block (SIB), Remaining Minimum System Information (RMSI), Other System Information (OSI), etc.

[0092] In the present disclosure, physical layer signaling may be, for example, Downlink Control Information (DCI), Uplink Control Information (UCI), and the like.

[0093] In the present disclosure, the terms index, identifier (ID), indicator, resource ID, etc. may be interchangeable. In the present disclosure, the terms sequence, list, set, group, cluster, subset, etc. may be interchangeable.

[0094] In the present disclosure, the terms panel, UE panel, panel group, beam, beam group, precoder, Uplink (UL) transmitting entity, Transmission / Reception Point (TRP), base station, Spatial Relation Information (SRI), spatial relation, 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 (PUCCH) group, PUCCH resource group), resource (e.g., reference signal resource, SRS resource), resource set (e.g., reference signal resource set), CORESET pool, downlink Transmission Configuration Indication state (TCI state) (DL TCI state), uplink TCI state (UL TCI state), unified TCI state, common TCI state, Quasi-Co-Location (QCL), QCL assumption, etc. may be read as interchangeable.

[0095] It should be noted that in this disclosure, "having the capability of..." may be read interchangeably as "supporting / reporting the capability of...".

[0096] (Wireless communication method) In each embodiment, one RACH attempt, a procedure from PRACH repetition to RAR reception determination, and the number of PRACH repetitions may be interpreted as interchangeable. One RACH attempt may be terminated by successful or unsuccessful reception of the corresponding RAR. Another RACH attempt may be initiated by unsuccessful reception of the RAR in one RACH attempt.

[0097] In each embodiment, the PRACH without repetition (first transmission scheme) may be a PRACH for which repetition is not applied / determined / configured / instructed. In each embodiment, the PRACH repetition using the same beam (second transmission scheme) may be a PRACH repetition using the same beam / TCI state / spatial domain filter for multiple PRACH repetitions. In each embodiment, the PRACH repetition using different beams (third transmission scheme) may be a PRACH repetition using different beams / TCI state / spatial domain filters for multiple PRACH repetitions. In each embodiment, the PRACH repetition using the same beam and different beams (fourth transmission scheme) may be a PRACH repetition including multiple sets of PRACH repetitions, each set including two or more repetitions, each set using the same beam / TCI state / spatial domain filter for two or more repetitions within each set, and each set using different beams / TCI state / spatial domain filters.

[0098] In each embodiment, the PRACH repetition function using the same beam and the PRACH repetition function using multiple different beams, two functions, two transmission methods, two transmission schemes, and two repetition schemes may be interpreted as interchangeable.

[0099] In each embodiment, the three functions, three transmission methods, and three transmission schemes, namely, the PRACH function without repetition, the PRACH repetition function using the same beam, and the PRACH repetition function using multiple different beams, may be interpreted as interchangeable.

[0100] In each embodiment, the four functions, four transmission methods, and four transmission schemes may be interpreted as interchangeable: a PRACH function without repetition, a PRACH repetition function using the same beam, a PRACH repetition function using multiple different beams, and a PRACH repetition function using the same beam and multiple different beams.

[0101] The operations of each figure in each embodiment (e.g., each of Figures 6 to 11) are applied to the case where one RAR window is used after multiple repetitions of PRACH (Type 1 multi-PRACH transmission), but may also be applied to the case where one RAR window is used after each repetition of PRACH (Type 2 multi-PRACH transmission).

[0102] The UE may determine one of a first transmission scheme for transmitting a Physical Random Access Channel (PRACH) without multiple repetitions, a second transmission scheme for transmitting the multiple repetitions using the same beam, a third transmission scheme for transmitting the multiple repetitions using different beams, and a fourth transmission scheme for transmitting the multiple repetitions using the same beam and different beams. The UE may transmit one or more PRACHs using the transmission schemes.

[0103] <Embodiment #1> This embodiment relates to whether PRACH repetition using the same beam and PRACH repetition using different beams are applied simultaneously.

[0104] <Option 1> It may be specified that the UE is not expected to simultaneously report capability for PRACH repetition using the same beam and capability for PRACH repetition using different beams.

[0105] <Option 2> The UE may be specified not to assume that the base station instructs / configures that PRACH repetition using the same beam and PRACH repetition using different beams are simultaneously enabled / configured.

[0106] The UE may be specified not to assume that PRACH repetition using the same beam and PRACH repetition using different beams are simultaneously enabled / configured by the SIB / RRC IE. The UE may be specified not to assume that there are any RACH resource sets configured with an indication for PRACH repetition using the same beam and any RACH resource sets configured with an indication for PRACH repetition using different beams. The UE may be specified not to assume that there are any RACH resource sets configured for PRACH repetition using the same beam and any RACH resource sets configured for PRACH repetition using different beams.

[0107] <Option 3> It may be specified that the UE does not assume that the two functions are applied simultaneously within one RACH attempt.

[0108] It may be specified that if a UE transmits PRACH repetitions on different beams in a single RACH attempt, the UE does not assume that it will transmit multiple PRACH repetitions using the same beam. It may be specified that if a UE transmits PRACH repetitions on different beams in a single RACH attempt, the UE does not assume that it will transmit PRACH occasions on any RACH resource set configured for PRACH repetitions using the same beam. It may be specified that if a UE transmits PRACH repetitions on different beams in a single RACH attempt, the UE does not assume that there are any RACH resource sets configured for both PRACH repetitions using the same beam and PRACH repetitions using different beams in a single RACH attempt.

[0109] Option 4: The UE may apply both functions simultaneously within one RACH attempt.

[0110] Option 5 may be specified such that the UE does not assume that the two features are applied simultaneously within one RACH attempt. Option 5 may be based on Option 3 with the additional requirement that the UE does not assume that it transmits multiple PRACH repetitions using the same beam in one RACH attempt within one RACH procedure and transmits multiple PRACH repetitions using different beams in another RACH attempt within that RACH procedure (before the expiration of the preamble transmission counter PREAMBLE_TRANSMISSION_COUNTER).

[0111] In the example of Figure 4A, the UE transmits multiple repetitions of PRACH (Msg1) using the same beam and different beams within one RACH attempt. One beam and one RAR window are used for two repetitions of PRACH. The RAR windows correspond to the different beams, respectively. This example is not allowed for options 3 / 5. This example is allowed for option 4.

[0112] In the example of Figure 4B, the UE transmits multiple repetitions of the PRACH using the same beam in one RACH attempt within one RACH procedure, and if it fails to receive the RAR, transmits multiple repetitions of the PRACH using different beams in another RACH attempt within the same RACH procedure. One RAR window is used per RACH attempt. This example is not allowed for Option 5. This example is allowed for Option 3.

[0113] The UE may support at least one of the following cases:

[0114] [Case 1] A case in which the UE reports only the capability for PRACH repetition using the same beam out of the two capabilities, and only PRACH repetition using the same beam is enabled / configured by the base station. The UE decides whether to transmit a PRACH without repetition or a PRACH repetition using the same beam.

[0115] [Case 2] Of the two capabilities, the UE reports only the capability for PRACH repetition using different beams, and only PRACH repetition using the same beam is enabled / configured by the base station. The UE transmits PRACH without repetition.

[0116] [Case 3] The UE reports capability for PRACH repetition using the same beam and capability for PRACH repetition using different beams, and only PRACH repetition using the same beam is enabled / configured by the base station. In Option 1, this case is an error case. In Options 2 / 3 / 4 / 5, the UE decides whether to transmit PRACH without repetition or PRACH repetition using the same beam.

[0117] [Case 4] Of the two capabilities, the UE reports only the capability for PRACH repetition using the same beam, and only PRACH repetition using different beams is enabled / configured by the base station. The UE transmits PRACH without repetition.

[0118] [Case 5] A case in which the UE reports only the capability for PRACH repetition using different beams out of the two capabilities, and only PRACH repetition using different beams is enabled / configured by the base station. The UE decides whether to transmit a PRACH without repetition or a PRACH repetition using different beams.

[0119] [Case 6] The UE reports capability for PRACH repetition using the same beam and capability for PRACH repetition using different beams, and only PRACH repetition using different beams is enabled / configured by the base station. In Option 1, this case is an error case. In Options 2 / 3 / 4 / 5, the UE decides whether to transmit PRACH without repetition or PRACH repetition using different beams.

[0120] [Case 7] The UE reports only the capability for PRACH repetition using the same beam among the two capabilities, and PRACH repetition using the same beam and PRACH repetition using different beams are simultaneously enabled / configured by the base station. In Options 1, 3, 4, and 5, the UE decides whether to transmit PRACH without repetition or PRACH repetition using the same beam. In Option 2, this case is an error case.

[0121] [Case 8] The UE reports only the capability for PRACH repetition using different beams among the two capabilities, and PRACH repetition using the same beam and PRACH repetition using different beams are simultaneously enabled / configured by the base station. In Options 1, 3, 4, and 5, the UE decides whether to transmit PRACH without repetition or PRACH repetition using different beams. In Option 2, this case is an error case.

[0122] [Case 9] The UE reports capability for PRACH repetition using the same beam and capability for PRACH repetition using different beams, and PRACH repetition using the same beam and PRACH repetition using different beams are simultaneously enabled / configured by the base station. In Option 1 / 2, this case is an error case. In Option 3, the UE decides whether to apply PRACH without repetition, PRACH repetition using the same beam, or PRACH repetition using different beams. In Option 4, the UE decides whether to apply PRACH without repetition, PRACH repetition using the same beam, PRACH repetition using different beams, or PRACH repetition using the same beam and different beams. In Option 5, the UE may follow at least one of the following actions for each RACH attempt: If the RACH attempt is the first RACH attempt of the RACH procedure, or if the UE has not transmitted a PRACH with repetition in any previous RACH attempt of the RACH procedure, the UE decides whether to apply a PRACH without repetition, a PRACH repetition using the same beam, or a PRACH repetition using different beams. If the UE has transmitted multiple PRACH repetitions using the same beam in any previous RACH attempt of the RACH procedure, the UE decides whether to apply a PRACH without repetition, or a PRACH repetition using the same beam. If the UE has transmitted multiple PRACH repetitions using different beams in any previous RACH attempt of the RACH procedure, the UE decides whether to apply a PRACH without repetition, or a PRACH repetition using different beams.

[0123] The UE may decide whether to perform a PRACH repetition and / or whether to use the same beam, different beams, or the same and different beams for the PRACH repetition based on at least one of the following factors: - Specification definition; - Indication by SIB / RRC IE / PDCCH order; - RO configuration parameters; - Current PREAMBLE_TRANSMISSION_COUNTER; - Random access restriction parameters, such as at least one of preambleTransMax, ra-ResponseWindow, and ra-ContentionResolutionTimer; - RSRP of one or more receptions of SSB or CSI-RS; - Priority for PRACH repetition using the same beam versus PRACH repetition using different beams; - UE capability for beam correspondence.

[0124] The UE may determine whether to perform multiple PRACH repetitions and whether to use the same beam, different beams, or the same beam and different beams for PRACH repetitions based on at least one of a deployment scenario, a duplex mode, a frequency range, and whether the band is licensed or unlicensed. The deployment scenario may be, for example, a terrestrial network or a non-terrestrial network, or the type of non-terrestrial network. The duplex mode may be, for example, TDD (unpaired spectrum) or FDD (paired spectrum). The frequency range may be, for example, FR1 / 2-1 / 2-2. Whether the band is licensed or unlicensed, whether the cell is licensed or unlicensed, whether the cell is a shared spectrum, and whether shared spectrum channel access is used may be interchangeable.

[0125] For example, a UE may transmit multiple PRACH repetitions using the same beam / different beams in a geostationary Earth orbit (GEO) scenario and transmit a PRACH without repetition in a low Earth orbit (LEO) scenario. For example, a UE may transmit multiple PRACH repetitions using the same beam / different beams in TDD (unpaired spectrum) and transmit a PRACH without repetition in FDD (paired spectrum). For example, a UE may transmit multiple PRACH repetitions using the same beam / different beams in a licensed band and transmit a PRACH without repetition in an unlicensed band. For example, a UE may transmit multiple PRACH repetitions using the same beam / different beams in FR2-2 and transmit a PRACH without repetition in FR1 / 2-1.

[0126] Example 1 This example relates to how a UE determines the transmission method / scheme of transmitting a PRACH without repetition or transmitting PRACH repetitions using the same beam (and the number of repetitions). This example may correspond to Cases 1, 3, and 7.

[0127] [Option 1-0] The transmission method may be specified by the specification. The specification may specify that the UE always transmits PRACH repetitions using the same beam, or that the UE always transmits PRACH without repetitions. The specification may specify different behavior for different cases (among cases 1 / 3 / 7).

[0128] [Option 1-1] The transmission method may be indicated by the SIB / RRC IE / PDCCH order (for a PDCCH-ordered RACH procedure). The base station may indicate whether to perform PRACH repetitions using the same beam (and the number of repetitions) by the SIB / RRC IE / PDCCH order.

[0129] [Option 1-2] The transmission method may be based on a RACH triggering method / RACH purpose. The RACH triggering method may be that the RACH is initiated by a PDCCH order / MAC entity / RRC. The RACH purpose may be initial access / system information (SI) request / SpCell BFR / reconfiguration with sync.

[0130] The relationship / mapping between whether or not to transmit PRACH repetitions using the same beam (and the number of repetitions) and the RACH triggering method / RACH purpose may be specified by a specification or may be configured by an SIB / RRC IE.

[0131] [Options 1-3] The transmission method may be based on RO configuration parameters, which may be at least one of the following: PRACH configuration index, PRACH format, number of SSBs per RO, number of FDM PRACH transmission occasions in one time instance, number of PRACH slots in one subframe, number of time-domain PRACH occasions in one PRACH slot, PRACH duration, zeroCorrelationZoneConfig (cyclic shift number configuration), and total number of preambles (for PRACH repetitions using the same beam).

[0132] The relationship / mapping between whether to transmit PRACH repetitions using the same beam (and the number of repetitions) and the RO configuration parameters may be specified by the specification or may be configured by the SIB / RRC IE.

[0133] [Options 1-4] The transmission method may be based on the PREAMBLE_TRANSMISSION_COUNTER. If the PREAMBLE_TRANSMISSION_COUNTER is greater than a certain value (specified by the specification or indicated by the SIB / RRC IE), the UE may transmit PRACH repetitions using the same beam. Otherwise, the UE may transmit PRACH without repetitions.

[0134] The number of PRACH repetitions may be based on the PREAMBLE_TRANSMISSION_COUNTER. For example, for a PREAMBLE_TRANSMISSION_COUNTER less than M1, the number of PRACH repetitions may be N1. For a PREAMBLE_TRANSMISSION_COUNTER greater than or equal to M1 and less than M2, the number of PRACH repetitions may be N2. For a PREAMBLE_TRANSMISSION_COUNTER greater than or equal to M2, the number of PRACH repetitions may be N3.

[0135] [Options 1-5] The transmission method may be based on the values ​​configured for the random access restriction parameters (at least one of preambleTransMax, ra-ResponseWindow, and ra-ContentionResolutionTimer). If the configured value for preambleTransMax is less than, greater than, or equal to a certain value Y1, if the configured value for ra-ResponseWindow is less than, greater than, or equal to a certain value Y2, or if the configured value for ra-ContentionResolutionTimer is less than, greater than, or equal to a certain value Y3, the UE may transmit PRACH repetitions using the same beam. Otherwise, the UE may transmit PRACH without repetitions. Here, Y1, Y2, and Y3 may be specified by the specification or indicated by the SIB / RRC IE.

[0136] The number of PRACH repetitions may be independent or dependent on the random access restriction parameter.

[0137] [Options 1-6] The transmission method may be based on the RSRP of one or more received SSB or CSI-RS.

[0138] The UE may determine whether to transmit PRACH repetitions using the same beam (and the number of repetitions) based on at least one of the RSRP value of the selected SSB / CSI-RS (according to the rules of Rel. 15 / 16 / 17) and the range of RSRP gap values. The gap may be between the RSRP of the selected SSB / CSI-RS and the maximum or average RSRP value among all RSRP values ​​(or an RSRP value exceeding rsrp-ThresholdSSB among the maximum to N RSRP values). Whether to transmit no PRACH repetitions or PRACH repetitions using the same beam (and the number of repetitions) may correspond to the range of gap values. The corresponding relationship / mapping may be specified in the specification or indicated by the SIB / RRC IE. For example, the mapping may associate whether or not to transmit PRACH repetitions (and number of repetitions) using the same beam with a gap being larger / smaller than a certain value.

[0139] The UE may transmit PRACH repetitions using the same beam when the received RSRP of the selected SSB / CSI-RS is smaller than a certain value, when the received RSRP of the selected SSB / CSI-RS is not one of the top (N) RSRP values ​​among all RSRP values, or when the received RSRP of the selected SSB / CSI-RS is at least M dB smaller than the maximum RSRP value or the average RSRP value. Otherwise, the UE may transmit PRACH without repetitions. Here, the certain values ​​N and M are integers and may be specified in the specification or indicated by the SIB / RRC IE.

[0140] The UE may determine whether to transmit PRACH repetitions using the same beam (and the number of repetitions) based on all RSRP values ​​(or RSRP values ​​exceeding rsrp-ThresholdSSB or the top N RSRP values), or based on the maximum / minimum / average / standard deviation of all RSRP values ​​(or RSRP values ​​exceeding rsrp-ThresholdSSB or the top N RSRP values), or based on the number of RSRP values ​​within a certain range. Whether to transmit PRACH without repetitions or PRACH repetitions using the same beam (and the number of repetitions) may correspond to at least one of different ranges for the maximum / minimum / average / standard deviation of all RSRP values ​​(or RSRP values ​​exceeding rsrp-ThresholdSSB or the top N RSRP values) and different ranges for the number of RSRP values ​​within a certain range. The corresponding relationship / mapping may be specified in the specification or may be indicated by an SIB / RRC IE. For example, the mapping may relate whether to transmit PRACH repetitions (and the number of repetitions) using the same beam to whether the RSRP-based value is greater than / less than a certain value.

[0141] A combination of at least two of options 1-1 to 1-6 may be used.

[0142] Example 2 This example relates to how a UE determines the transmission method / scheme of transmitting a PRACH without repetition or transmitting PRACH repetitions using different beams. This example may correspond to Cases 5, 6, and 8.

[0143] [Option 2-0] The transmission method may be specified by the specification. The specification may specify that the UE always transmits PRACH repetitions with different beams, or that the UE always transmits PRACH without repetitions. The specification may specify different behavior for different cases (among Cases 5 / 6 / 8).

[0144] [Option 2-1] The transmission method may be indicated by the SIB / RRC IE / PDCCH order (for a PDCCH-ordered RACH procedure). The base station may indicate whether to perform PRACH repetitions using different beams (and the number of repetitions / beams) by the SIB / RRC IE / PDCCH order.

[0145] [Option 2-2] The transmission method may be based on a RACH triggering method / RACH purpose. The RACH triggering method may be that the RACH is initiated by a PDCCH order / MAC entity / RRC. The RACH purpose may be initial access / system information (SI) request / SpCell BFR / reconfiguration with sync.

[0146] The relationship / mapping between whether to transmit PRACH repetitions using different beams (and the number of repetitions / beams, or multiple beams for multiple repetitions) and the RACH triggering method / RACH purpose may be defined by a specification or may be configured by a SIB / RRC IE.

[0147] [Option 2-3] The transmission method may be based on RO configuration parameters, which may be at least one of the following: PRACH configuration index, PRACH format, number of SSBs per RO, number of FDM PRACH transmission occasions in one time instance, number of PRACH slots in one subframe, number of time-domain PRACH occasions in one PRACH slot, PRACH duration, zeroCorrelationZoneConfig (cyclic shift number configuration), and total number of preambles (for PRACH repetitions using different beams).

[0148] The relationship / mapping between whether to transmit PRACH repetitions using different beams (and the number of repetitions / beams) and the RO configuration parameters may be specified by a specification or configured by an SIB / RRC IE.

[0149] [Options 2-4] The transmission method may be based on the PREAMBLE_TRANSMISSION_COUNTER. If the PREAMBLE_TRANSMISSION_COUNTER is greater than a certain value (specified by the specification or indicated by the SIB / RRC IE), the UE may transmit PRACH repetitions using different beams. Otherwise, the UE may transmit PRACH without repetitions.

[0150] The number of PRACH repetitions / beams may be based on the PREAMBLE_TRANSMISSION_COUNTER. For example, for a PREAMBLE_TRANSMISSION_COUNTER smaller than M1, the number of PRACH repetitions / beams may be N1. For a PREAMBLE_TRANSMISSION_COUNTER equal to or greater than M1 and smaller than M2, the number of PRACH repetitions / beams may be N2. For a PREAMBLE_TRANSMISSION_COUNTER equal to or greater than M2, the number of PRACH repetitions / beams may be N3.

[0151] [Option 2-5] The transmission method may be based on the values ​​configured for the random access restriction parameters (at least one of preambleTransMax, ra-ResponseWindow, and ra-ContentionResolutionTimer). If the configured value for preambleTransMax is less than, greater than, or equal to a certain value Y1, if the configured value for ra-ResponseWindow is less than, greater than, or equal to a certain value Y2, or if the configured value for ra-ContentionResolutionTimer is less than, greater than, or equal to a certain value Y3, the UE may transmit PRACH repetitions using different beams. Otherwise, the UE may transmit PRACH without repetitions. Here, Y1, Y2, and Y3 may be specified by the specification or indicated by the SIB / RRC IE.

[0152] The number of PRACH repetitions / beams may be independent or dependent on the random access restriction parameter.

[0153] [Option 2-6] The transmission method may be based on the RSRP of one or more received SSB or CSI-RS.

[0154] The UE may determine whether to transmit PRACH repetitions using different beams (and the number of repetitions / beams) based on at least one of the RSRP value of the selected SSB / CSI-RS (according to the rules of Rel. 15 / 16 / 17) and the range of RSRP gap values. The gap may be between the RSRP of the selected SSB / CSI-RS and the maximum or average RSRP value among all RSRP values ​​(or an RSRP value exceeding rsrp-ThresholdSSB among the maximum to N RSRP values). Whether to transmit no PRACH repetitions or PRACH repetitions using different beams (and the number of repetitions / beams) may correspond to the range of gap values. The corresponding relationship / mapping may be specified in the specification or indicated by the SIB / RRC IE. For example, the mapping may associate whether or not to transmit PRACH repetitions using different beams (and number of repetitions / beams) with gaps being larger / smaller than a certain value.

[0155] The UE may transmit PRACH repetitions using different beams when the received RSRP of the selected SSB / CSI-RS is smaller than a certain value, when the received RSRP of the selected SSB / CSI-RS is not one of the top (N) RSRP values ​​among all RSRP values, or when the received RSRP of the selected SSB / CSI-RS is at least M dB smaller than the maximum RSRP value or the average RSRP value. Otherwise, the UE may transmit PRACH without repetitions, where the certain values ​​N and M are integers and may be specified in the specification or indicated by the SIB / RRC IE.

[0156] The UE may determine whether to transmit PRACH repetitions using different beams (and the number of repetitions / beams) based on all RSRP values ​​(or RSRP values ​​exceeding rsrp-ThresholdSSB or the top N RSRP values), or based on the maximum / minimum / average / standard deviation of all RSRP values ​​(or RSRP values ​​exceeding rsrp-ThresholdSSB or the top N RSRP values), or based on the number of RSRP values ​​within a certain range. Whether to transmit PRACH without repetitions or PRACH repetitions using different beams (and the number of repetitions / beams) may correspond to at least one of different ranges for the maximum / minimum / average / standard deviation of all RSRP values ​​(or RSRP values ​​exceeding rsrp-ThresholdSSB or the top N RSRP values) and different ranges for the number of RSRP values ​​within a certain range. The corresponding relationship / mapping may be specified in a specification or may be indicated by an SIB / RRC IE. For example, the mapping may relate whether to transmit PRACH repetitions (and the number of repetitions / beams) using different multiple beams to whether the RSRP-based value is greater than / less than a certain value.

[0157] [Option 2-7] The transmission method may be based on the UE capability of beam correspondence. If the UE does not have / report capability of beam correspondence, the UE may transmit PRACH repetitions using different beams. If the UE has / reports capability of beam correspondence, the UE may transmit PRACH without repetitions.

[0158] A combination of at least two of options 2-1 to 2-7 may be used.

[0159] Example 3 This example relates to how a UE determines a transmission method / scheme (one of three transmission methods) of transmitting a PRACH without repetition, transmitting PRACH repetitions using the same beam, or transmitting PRACH repetitions using different beams. This example may correspond to Case 9.

[0160] [Option 3-0] The transmission method may be specified by a specification, which may specify that the UE always transmits PRACH repetitions using the same beam, or that the UE always transmits PRACH repetitions using different beams (and the number of beams), or that the UE always transmits PRACH without repetitions.

[0161] [Option 3-1] The transmission method may be indicated by the SIB / RRC IE / PDCCH order (for a PDCCH-ordered RACH procedure). The base station may indicate one of three transmission methods (and the number of repetitions / beams in case of multiple PRACH repetitions) by the SIB / RRC IE / PDCCH order.

[0162] [Option 3-2] The transmission method may be based on a RACH triggering method / RACH purpose. The RACH triggering method may be that the RACH is initiated by a PDCCH order / MAC entity / RRC. The RACH purpose may be initial access / system information (SI) request / SpCell BFR / reconfiguration with sync.

[0163] The relationship / mapping between whether to transmit a PRACH without repetition, transmit a PRACH repetition using the same beam (and the number of repetitions), or transmit a PRACH repetition using different beams (and the number of repetitions / number of beams) and the RACH triggering method / RACH purpose may be specified by a specification or may be set by an SIB / RRC IE.

[0164] [Option 3-3] The transmission method may be based on RO configuration parameters, which may be at least one of a PRACH configuration index, a PRACH format, the number of SSBs per RO, the number of FDM-multiplexed PRACH transmission occasions in one time instance, the number of PRACH slots in one subframe, the number of time-domain PRACH occasions in one PRACH slot, a PRACH duration, zeroCorrelationZoneConfig (cyclic shift number setting), and the total number of preambles (for PRACH repetitions using the same beam / different beams).

[0165] The relationship / mapping between transmitting PRACH without repetition, transmitting PRACH repetitions using the same beam (and the number of repetitions), transmitting PRACH repetitions using different beams (and the number of repetitions / number of beams) and the RO configuration parameters may be specified by a specification or may be configured by an SIB / RRC IE.

[0166] [Option 3-4] The transmission method may be based on the PREAMBLE_TRANSMISSION_COUNTER.

[0167] Transmitting PRACH without repetition, transmitting PRACH repetitions using the same beam (and the number of repetitions), or transmitting PRACH repetitions using different beams (and the number of repetitions / beams) may correspond to different ranges of PREAMBLE_TRANSMISSION_COUNTER values. The relationship / mapping between the three transmission methods and the ranges may be specified by a specification or configured by an SIB / RRC IE. For example, the mapping may associate one of the three transmission methods with an RSRP-based value greater than / less than a certain value.

[0168] If PREAMBLE_TRANSMISSION_COUNTER is greater than or equal to X0 / less than X1, the UE may transmit PRACH without repetitions. If PREAMBLE_TRANSMISSION_COUNTER is greater than or equal to X2 / less than X3, the UE may transmit PRACH repetitions using the same beam. The number of PRACH repetitions may be determined based on PREAMBLE_TRANSMISSION_COUNTER. For example, if Y0 < (or ≦) PREAMBLE_TRANSMISSION_COUNTER < (or ≦) Y1, the number of PRACH repetitions may be N1. If PREAMBLE_TRANSMISSION_COUNTER is greater than or equal to X4 / less than X5, the UE may transmit PRACH repetitions using different beams. The number of PRACH repetitions / beams may be determined based on PREAMBLE_TRANSMISSION_COUNTER. For example, if Y2<(or≦) PREAMBLE_TRANSMISSION_COUNTER<(or≦) Y3, the number of PRACH repetitions / beams may be N2.

[0169] [Options 3-5] The transmission method may be based on the values ​​set for the random access restriction parameters (at least one of preambleTransMax, ra-ResponseWindow, and ra-ContentionResolutionTimer).

[0170] Transmitting PRACH without repetition, transmitting PRACH repetitions using the same beam (and the number of repetitions), or transmitting PRACH repetitions using different beams (and the number of repetitions / beams) may correspond to different ranges of values ​​for the random access restriction parameter. The relationship / mapping between the three transmission methods and the ranges may be specified by a specification or configured by an SIB / RRC IE. For example, the mapping may associate one of the three transmission methods with an RSRP-based value greater than / less than a certain value.

[0171] When preambleTransMax is greater than or equal to X0 or less than X1, when ra-ResponseWindow is greater than or equal to Y0 or less than Y1, and when ra-ContentionResolutionTimer is greater than or equal to Z0 or less than Z1, the UE may transmit PRACH without repetition. When preambleTransMax is greater than or equal to X2 or less than X3, when ra-ResponseWindow is greater than or equal to Y2 or less than Y3, and when ra-ContentionResolutionTimer is greater than or equal to Z2 or less than Z3, the UE may transmit PRACH repetitions using the same beam. When preambleTransMax is greater than or equal to X4 or less than X5, when ra-ResponseWindow is greater than or equal to Y4 or less than Y5, and when ra-ContentionResolutionTimer is greater than or equal to Z4 or less than Z5, the UE may transmit PRACH repetitions using different beams.

[0172] The number of PRACH repetitions / beams may be independent or dependent on the random access restriction parameter.

[0173] [Options 3-6] The transmission method may be based on the RSRP of one or more received SSB or CSI-RS.

[0174] The UE may determine one of the three transmission methods (and the number of repetitions / beams in case of multiple PRACH repetitions) based on at least one of the following: the RSRP value of the selected SSB / CSI-RS (according to the rules of Rel. 15 / 16 / 17), the range of the RSRP gap value, all RSRP values ​​(or RSRP values ​​above rsrp-ThresholdSSB or the top N RSRP values), the maximum / minimum / average / standard deviation of all RSRP values ​​(or RSRP values ​​above rsrp-ThresholdSSB or the top N RSRP values), and the number of RSRP values ​​within a certain range. The gap may be the gap between the RSRP of the selected SSB / CSI-RS and the maximum or average RSRP value among all RSRP values ​​(or an RSRP value exceeding rsrp-ThresholdSSB among the maximum to N RSRP values). At least one of three transmission methods may correspond to a range of gap values. The corresponding relationship / mapping may be defined in a specification or indicated by an SIB / RRC IE. For example, the mapping may associate one of the three transmission methods with a gap greater than / less than a certain value.

[0175] The RSRP of the received SSB / CSI-RS selected (by the rules of Rel. 15 / 16 / 17) is within a certain range, the gap is within a certain range, all RSRP values ​​(or RSRP values ​​exceeding rsrp-ThresholdSSB, or the top N RSRP values) are within a certain range, the maximum / minimum / average / standard deviation of all RSRP values ​​(or RSRP values ​​exceeding rsrp-ThresholdSSB, or the top N RSRP values) are within a certain range, or ... If the RSRP value of the selected SSB / CSI-RS is not one of the highest (top X) RSRP values ​​in at least one of the following cases: the RSRP value is within a certain range; the maximum / minimum / average / standard deviation of the received RSRP values ​​of all SSB / CSI-RS are within a certain range; or the maximum / minimum / average / standard deviation of the RSRP values ​​exceeding rsrp-ThresholdSSB are within a certain range, the UE may transmit PRACH repetitions using different beams, where X and M are integers and may be specified in the specification or indicated by the SIB / RRC IE. Otherwise, the UE may transmit PRACH repetitions using the same beam.

[0176] [Options 3-7] The transmission method may be based on a combination of Examples 1 and 2.

[0177] The UE may first determine whether to transmit PRACH repetitions using the same beam based on Example 1. If PRACH repetitions using the same beam are not selected, the UE may determine whether to transmit PRACH repetitions using different beams based on Example 2.

[0178] The UE may first determine whether to transmit PRACH repetitions using different beams based on Example 2. If PRACH repetitions using different beams are not selected, the UE may determine whether to transmit PRACH repetitions using the same beam based on Example 1.

[0179] [Option 3-8] The transmission method may be based on a priority for PRACH repetitions using the same beam and PRACH repetitions using different beams.

[0180] The priority of the two repetition schemes (PRACH repetition using the same beam and PRACH repetition using different beams) may be specified or indicated by the base station (via SIB / RRC IE / PDCCH order). For example, the priority of PRACH repetition using different beams may be higher or lower than the priority of PRACH repetition using the same beam.

[0181] For a RACH attempt, if the RACH attempt is the first (or up to X) RACH attempt in the current RACH procedure (the value of PREAMBLE_TRANSMISSION_COUNTER is 0 (or less than X)), or if the UE has not transmitted multiple PRACH repetitions in any of the previous X (consecutive) RACH attempts in the RACH procedure, the UE may decide to apply a repetition scheme with a higher priority in the RACH attempt. The value of X may be specified in the specification or indicated by a SIB / RRC IE / PDCCH order. The value of X may be any integer greater than or equal to 1.

[0182] If the priority of PRACH repetition using the same beam is higher than the priority of PRACH repetition using different beams, the UE may decide whether to perform PRACH repetition using different beams based on Example 2.

[0183] If the priority of PRACH repetition using different beams is higher than the priority of PRACH repetition using the same beam, the UE may decide whether to perform PRACH repetition using the same beam based on Example 1.

[0184] In one RACH attempt, if the UE has transmitted multiple PRACH repetitions in any of the previous X (consecutive) RACH attempts within that RACH procedure and that RACH attempt fails, the UE may follow one of several actions: The value of X may be specified in the specification or may be indicated by the SIB / RRC IE / PDCCH order. The value of X may be any integer greater than or equal to 1.

[0185] Action A: The UE performs multiple PRACH repetitions using lower priority repetition schemes within that RACH attempt.

[0186] If the priority of a PRACH repetition using the same beam is higher than the priority of a PRACH repetition using different beams, and if the UE has transmitted multiple PRACH repetitions using the same beam in a previous RACH attempt and failed, the UE may transmit multiple PRACH repetitions using different beams.

[0187] If the priority of a PRACH repetition using different beams is higher than the priority of a PRACH repetition using the same beam, and the UE has transmitted multiple PRACH repetitions using different beams in a previous RACH attempt and failed, the UE may transmit multiple PRACH repetitions using the same beam.

[0188] Action B: The UE decides whether to apply the repetition scheme with a lower priority within that RACH attempt.

[0189] If the priority of a PRACH repetition using the same beam is higher than the priority of a PRACH repetition using different beams, and the UE has transmitted multiple PRACH repetitions using the same beam in a previous RACH attempt and failed, the UE may decide whether to transmit multiple PRACH repetitions using different beams based on Example 2.

[0190] In the example of Figure 5A, if the priority of a PRACH repetition using the same beam is higher than the priority of a PRACH repetition using different beams, and the UE transmitted multiple PRACH repetitions using the same beam in a previous RACH attempt and failed to receive the RAR, the UE may transmit multiple PRACH repetitions using different beams in the next RACH attempt.

[0191] If the priority of a PRACH repetition using different beams is higher than the priority of a PRACH repetition using the same beam, and the UE has transmitted multiple PRACH repetitions using different beams in a previous RACH attempt and failed, the UE may decide whether to transmit multiple PRACH repetitions using the same beam based on Example 1.

[0192] In the example of Figure 5B, if the priority of PRACH repetitions using different beams is higher than the priority of PRACH repetitions using the same beam, and the UE transmitted multiple PRACH repetitions using different beams in a previous RACH attempt and failed to receive the RAR, the UE may transmit multiple PRACH repetitions using the same beam in the next RACH attempt.

[0193] [Option 3-9] The transmission method may be based on the UE's capability of beam correspondence. If the UE does not have / reports capability of beam correspondence, the UE may transmit PRACH repetitions using different beams. If the UE has / reports capability of beam correspondence, the UE may decide whether to transmit PRACH without repetitions or PRACH repetitions using the same beam based on Example 1.

[0194] A combination of at least two of options 3-1 through 3-9 may be used.

[0195] Example 4 This example relates to how a UE determines a transmission method / scheme (one of four transmission methods) of transmitting a PRACH without repetition, transmitting PRACH repetitions using the same beam, transmitting PRACH repetitions using different beams, or transmitting PRACH repetitions using the same beam and different beams. This example may correspond to Case 9.

[0196] [Option 4-0] The transmission method may be specified by a specification. The specification may specify that the UE always transmits PRACH repetitions using the same beam, or that the UE always transmits PRACH repetitions using different beams (and the number of beams), or that the UE always transmits PRACH repetitions using the same beam and different beams (and the number of beams), or that the UE always transmits PRACH repetitions without repetitions.

[0197] [Option 4-1] The transmission method may be indicated by the SIB / RRC IE / PDCCH order (for a PDCCH-ordered RACH procedure). The base station may indicate one of four transmission methods (and the number of repetitions / beams in case of multiple PRACH repetitions) by the SIB / RRC IE / PDCCH order.

[0198] [Option 4-2] The transmission method may be based on a RACH triggering method / RACH purpose. The RACH triggering method may be that the RACH is initiated by a PDCCH order / MAC entity / RRC. The RACH purpose may be initial access / system information (SI) request / SpCell BFR / reconfiguration with sync.

[0199] The relationship / mapping between transmitting PRACH without repetition, transmitting PRACH repetitions using the same beam (and the number of repetitions), transmitting PRACH repetitions using different beams (and the number of repetitions / number of beams), transmitting PRACH repetitions using the same beam and different beams (and the number of repetitions per beam) and the RACH triggering method / RACH purpose may be specified by a specification or may be set by an SIB / RRC IE.

[0200] [Option 4-3] The transmission method may be based on RO configuration parameters, which may be at least one of the following: PRACH configuration index, PRACH format, number of SSBs per RO, number of FDM PRACH transmission occasions in one time instance, number of PRACH slots in one subframe, number of time-domain PRACH occasions in one PRACH slot, PRACH duration, zeroCorrelationZoneConfig (cyclic shift number setting), and total number of preambles (for PRACH repetition using the same beam / different beams).

[0201] The relationship / mapping between transmitting PRACH without repetition, transmitting PRACH repetitions using the same beam (and the number of repetitions), transmitting PRACH repetitions using different beams (and the number of repetitions / number of beams), transmitting PRACH repetitions using the same beam and different beams (and the number of repetitions per beam) and the RO configuration parameters may be specified by a specification or may be configured by an SIB / RRC IE.

[0202] [Option 4-4] The transmission method may be based on PREAMBLE_TRANSMISSION_COUNTER.

[0203] Transmitting PRACH without repetitions, transmitting PRACH repetitions using the same beam (and the number of repetitions), transmitting PRACH repetitions using different beams (and the number of repetitions / beams), or transmitting PRACH repetitions using the same beam and different beams (and the number of repetitions per beam) may correspond to different ranges of values ​​for PREAMBLE_TRANSMISSION_COUNTER. The relationship / mapping between the four transmission methods and their ranges may be specified by a specification or configured by an SIB / RRC IE. For example, the mapping may associate one of the four transmission methods with an RSRP-based value greater than / less than a certain value.

[0204] If PREAMBLE_TRANSMISSION_COUNTER is greater than or equal to X0 / less than X1, the UE may transmit PRACH without repetitions. If PREAMBLE_TRANSMISSION_COUNTER is greater than or equal to X2 / less than X3, the UE may transmit PRACH repetitions using the same beam. The number of PRACH repetitions may be determined based on PREAMBLE_TRANSMISSION_COUNTER. For example, if Y0 < (or ≦) PREAMBLE_TRANSMISSION_COUNTER < (or ≦) Y1, the number of PRACH repetitions may be N1. If PREAMBLE_TRANSMISSION_COUNTER is greater than or equal to X4 / less than X5, the UE may transmit PRACH repetitions using different beams. The number of PRACH repetitions / beams may be determined based on PREAMBLE_TRANSMISSION_COUNTER. For example, if Y2 < (or ≦) PREAMBLE_TRANSMISSION_COUNTER < (or ≦) Y3, the number of PRACH repetitions / the number of beams may be N2. If PREAMBLE_TRANSMISSION_COUNTER is greater than or equal to X6 / less than X7, the UE may transmit PRACH repetitions using the same beam and different beams. At least one of the number of beams, the number of PRACH repetitions for each beam, and the total number of PRACH repetitions may be determined based on PREAMBLE_TRANSMISSION_COUNTER. For example, if Y4 < (or ≦) PREAMBLE_TRANSMISSION_COUNTER < (or ≦) Y5, the number of PRACH beams may be N3, and the total number of PRACH repetitions may be N4.

[0205] [Option 4-5] The transmission method may be based on the values ​​set for the random access restriction parameters (at least one of preambleTransMax, ra-ResponseWindow, and ra-ContentionResolutionTimer).

[0206] Transmitting PRACH without repetition, transmitting PRACH repetitions using the same beam (and the number of repetitions), transmitting PRACH repetitions using different beams (and the number of repetitions / beams), or transmitting PRACH repetitions using the same beam and different beams (and the number of repetitions per beam) may correspond to different ranges of values ​​for the random access restriction parameter. The relationship / mapping between the four transmission methods and their ranges may be specified by a specification or configured by an SIB / RRC IE. For example, the mapping may associate one of the four transmission methods with an RSRP-based value being greater / less than a certain value.

[0207] When preambleTransMax is greater than or equal to X0 or less than X1, when ra-ResponseWindow is greater than or equal to Y0 or less than Y1, and when ra-ContentionResolutionTimer is greater than or equal to Z0 or less than Z1, the UE may transmit PRACH without repetition. When preambleTransMax is greater than or equal to X2 or less than X3, when ra-ResponseWindow is greater than or equal to Y2 or less than Y3, and when ra-ContentionResolutionTimer is greater than or equal to Z2 or less than Z3, the UE may transmit PRACH repetitions using the same beam. When preambleTransMax is greater than or equal to X4 or less than X5, when ra-ResponseWindow is greater than or equal to Y4 or less than Y5, and when ra-ContentionResolutionTimer is greater than or equal to Z4 or less than Z5, the UE may transmit PRACH repetitions using different beams. When preambleTransMax is greater than or equal to X6 / less than X7, when ra-ResponseWindow is greater than or equal to Y6 / less than Y7, and when ra-ContentionResolutionTimer is greater than or equal to Z6 / less than Z7, the UE may transmit PRACH repetitions using the same beam and different beams.

[0208] At least one of the number of beams, the number of PRACH repetitions for each beam, and the total number of PRACH repetitions may be independent or dependent on the random access restriction parameter.

[0209] [Options 4-6] The transmission method may be based on the RSRP of one or more received SSB or CSI-RS.

[0210] The UE may determine one of the four transmission methods (and the number of repetitions / beams in case of multiple PRACH repetitions) based on at least one of the following: the RSRP value of the selected SSB / CSI-RS (according to the rules of Rel. 15 / 16 / 17), the range of the RSRP gap value, all RSRP values ​​(or RSRP values ​​above rsrp-ThresholdSSB or the top N RSRP values), the maximum / minimum / average / standard deviation of all RSRP values ​​(or RSRP values ​​above rsrp-ThresholdSSB or the top N RSRP values), and the number of RSRP values ​​within a certain range. The gap may be the gap between the RSRP of the selected SSB / CSI-RS and the maximum or average RSRP value among all RSRP values ​​(or an RSRP value exceeding rsrp-ThresholdSSB among the maximum to Nth RSRP values). At least one of four transmission methods may correspond to a range of gap values. The corresponding relationship / mapping may be specified in the specification or indicated by the SIB / RRC IE. For example, the mapping may associate one of the four transmission methods with a gap greater than / less than a certain value.

[0211] If there is reception of more than N SSB / CSI-RS with RSRP greater than X1 and the maximum RSRP is lower than X2, the UE may transmit multiple PRACH repetitions using different beams and may transmit multiple repetitions on each beam or on some of the different beams.

[0212] If there is reception of more than N SSB / CSI-RS with RSRP greater than X3, the UE may transmit multiple PRACH repetitions using different beams.

[0213] If there is reception of only one SSB / CSI-RS with RSRP greater than X1 and the maximum RSRP is lower than X2, the UE may transmit multiple PRACH repetitions using the same multiple beams.

[0214] [Options 4-7] The transmission method may be based on a combination of Examples 1 and 2.

[0215] The UE may use Example 1 / Example 2 to decide whether to apply the same beam, different beams, or the same beam and different beams for multiple iterations.

[0216] The UE may apply Example 1 (determine whether PRACH repetitions using the same beam are necessary) and then apply Example 2 (determine whether PRACH repetitions using different beams are necessary). The UE may follow several steps: [Step 1] The UE may determine whether to transmit PRACH repetitions using the same beam based on Example 1. [Step 2] The UE may determine whether to transmit PRACH repetitions using different beams based on Example 2.

[0217] The UE may follow at least one of the following cases: - If PRACH repetition using the same beam is not selected according to Example 1 and PRACH repetition using different beams is not selected according to Example 2, the UE may transmit PRACH without repetition. - If PRACH repetition using the same beam is not selected according to Example 1 and PRACH repetition using different beams is selected according to Example 2, the UE may transmit PRACH repetition using different beams. - If PRACH repetition using the same beam is selected according to Example 1 and PRACH repetition using different beams is not selected according to Example 2, the UE may transmit PRACH repetition using the same beam. - If PRACH repetition using the same beam is selected according to Example 1 and PRACH repetition using different beams is selected according to Example 2, the UE may transmit PRACH repetition using the same beam.

[0218] The UE may apply Example 2 (determine whether PRACH repetition using different beams is necessary) and then apply Example 1 (determine whether PRACH repetition using the same beam is necessary). The UE may follow several steps: [Step 1] The UE may determine whether to transmit PRACH repetition using different beams based on Example 2. [Step 2] The UE may determine, for each beam of the PRACH repetition transmission beams determined in step 1, whether PRACH repetition using that beam is necessary based on Example 1.

[0219] The UE may follow at least one of the following cases: - If PRACH repetition using different beams is not selected according to Example 2 and PRACH repetition using the same beam is not selected according to Example 1, the UE may transmit a PRACH without repetition. - If PRACH repetition using different beams is not selected according to Example 2 and PRACH repetition using the same beam is selected according to Example 1, the UE may transmit PRACH repetition using the same beam. - If PRACH repetition using different beams is selected according to Example 2, the UE may follow at least one of the following (a) and (b) for each beam of the determined multiple beams: (a) If PRACH repetition using the same beam is selected according to Example 1, the UE may transmit multiple repetitions on that beam. (b) If PRACH repetition using the same beam is not selected according to Example 1, the UE may transmit only one repetition on that beam.

[0220] [Options 4-8] The transmission method may be based on a priority for PRACH repetitions using the same beam and PRACH repetitions using different beams.

[0221] The priority of the two repetition schemes (PRACH repetition using the same beam and PRACH repetition using different beams) may be specified or indicated by the base station (via SIB / RRC IE / PDCCH order). For example, the priority of PRACH repetition using different beams may be higher or lower than the priority of PRACH repetition using the same beam.

[0222] For a RACH attempt, if the RACH attempt is the first (or up to X) RACH attempt in the current RACH procedure (the value of PREAMBLE_TRANSMISSION_COUNTER is 0 (or less than X)), or if the UE has not transmitted multiple PRACH repetitions in any of the previous X (consecutive) RACH attempts in the RACH procedure, the UE may decide to apply a repetition scheme with a higher priority in the RACH attempt. The value of X may be specified in the specification or indicated by a SIB / RRC IE / PDCCH order. The value of X may be any integer greater than or equal to 1.

[0223] If the priority of PRACH repetition using the same beam is higher than the priority of PRACH repetition using different beams, the UE may decide whether to perform PRACH repetition using different beams based on Example 2.

[0224] If the priority of PRACH repetition using different beams is higher than the priority of PRACH repetition using the same beam, the UE may decide whether to perform PRACH repetition using the same beam based on Example 1.

[0225] In one RACH attempt, if the UE has transmitted multiple PRACH repetitions in any of the previous X (consecutive) RACH attempts within that RACH procedure and that RACH attempt fails, the UE may follow one of several actions: The value of X may be specified in the specification or may be indicated by the SIB / RRC IE / PDCCH order. The value of X may be any integer greater than or equal to 1.

[0226] Action A: The UE performs multiple PRACH repetitions using lower priority repetition schemes within that RACH attempt.

[0227] If the priority of a PRACH repetition using the same beam is higher than the priority of a PRACH repetition using different beams, and if the UE has transmitted multiple PRACH repetitions using the same beam in a previous RACH attempt and failed, the UE may transmit multiple PRACH repetitions using different beams.

[0228] If the priority of a PRACH repetition using different beams is higher than the priority of a PRACH repetition using the same beam, and the UE has transmitted multiple PRACH repetitions using different beams in a previous RACH attempt and failed, the UE may transmit multiple PRACH repetitions using the same beam.

[0229] If the UE has transmitted multiple PRACH repeats with a higher priority in any of the previous X (consecutive) RACH attempts within the RACH procedure and the RACH attempt has failed, and if the UE has transmitted multiple PRACH repeats with a lower priority in any of the previous Y (consecutive) RACH attempts within the RACH procedure and the RACH attempt has failed, the UE may transmit multiple PRACH repeats using the same beam and different beams.

[0230] Action B: The UE transmits multiple PRACH repetitions using the same beam and different beams within its RACH attempt.

[0231] If the priority of a PRACH repetition using the same beam is higher than the priority of a PRACH repetition using different beams, and if the UE has transmitted multiple PRACH repetitions using the same beam in a previous RACH attempt and failed, the UE may transmit multiple PRACH repetitions using the same beam and different beams.

[0232] If the priority of a PRACH repetition using different beams is higher than the priority of a PRACH repetition using the same beam, and if the UE has transmitted multiple PRACH repetitions using different beams in a previous RACH attempt and failed, the UE may transmit multiple PRACH repetitions using the same beam and different beams.

[0233] Action C: The UE decides whether to apply the repetition scheme with a lower priority within that RACH attempt.

[0234] If the priority of a PRACH repetition using the same beam is higher than the priority of a PRACH repetition using different beams, and the UE has transmitted multiple PRACH repetitions using the same beam in a previous RACH attempt and failed, the UE may decide whether to transmit multiple PRACH repetitions using different beams based on Example 2.

[0235] If the priority of a PRACH repetition using different beams is higher than the priority of a PRACH repetition using the same beam, and the UE has transmitted multiple PRACH repetitions using different beams in a previous RACH attempt and failed, the UE may decide whether to transmit multiple PRACH repetitions using the same beam based on Example 1.

[0236] If the UE has transmitted multiple PRACH repeats with a higher priority in any of the previous X (consecutive) RACH attempts within the RACH procedure and the RACH attempt has failed, and if the UE has transmitted multiple PRACH repeats with a lower priority in any of the previous Y (consecutive) RACH attempts within the RACH procedure and the RACH attempt has failed, the UE may transmit multiple PRACH repeats using the same beam and different beams.

[0237] Action D: The UE may decide whether to transmit multiple PRACH repetitions using the same beam and different beams within the RACH attempt.

[0238] If the priority of a PRACH repetition using the same beam is higher than the priority of a PRACH repetition using different beams, and the UE has transmitted multiple PRACH repetitions using the same beam in a previous RACH attempt and failed, the UE may determine whether to transmit multiple PRACH repetitions using different beams based on Example 2. In this case, the UE may follow at least one of the following operations D-1 and D-2. [[[Operation D-1]]] If it is determined to transmit multiple PRACH repetitions using different beams, the UE transmits multiple PRACH repetitions using the same beam and different beams. Otherwise, the UE transmits multiple PRACH repetitions using the same beam. [[[Operation D-2]]] If it is determined to transmit multiple PRACH repetitions using different beams, the UE transmits multiple PRACH repetitions using the same beam and different beams. Otherwise, the UE transmits PRACH without repetitions.

[0239] If the priority of PRACH repetitions using different beams is higher than the priority of PRACH repetitions using the same beam, and the UE has transmitted multiple PRACH repetitions using different beams in a previous RACH attempt and failed, the UE may determine whether to transmit multiple PRACH repetitions using the same beam based on Example 1. In this case, the UE may follow at least one of the following operations D-3 and D-4. [[[Operation D-3]]] If it is determined to transmit multiple PRACH repetitions using the same beam, the UE transmits multiple PRACH repetitions using the same beam and different beams. Otherwise, the UE transmits multiple PRACH repetitions using different beams. [[[Operation D-4]]] If it is determined to transmit multiple PRACH repetitions using the same beam, the UE transmits multiple PRACH repetitions using the same beam and different beams. Otherwise, the UE transmits PRACH without repetitions.

[0240] If the UE has transmitted multiple PRACH repeats with a higher priority in any of the previous X (consecutive) RACH attempts within the RACH procedure and the RACH attempt has failed, and if the UE has transmitted multiple PRACH repeats with a lower priority in any of the previous Y (consecutive) RACH attempts within the RACH procedure and the RACH attempt has failed, the UE may transmit multiple PRACH repeats using the same beam and different beams.

[0241] A specific example of operation A / C will be shown below.

[0242] In the example of Figure 6, if the priority of a PRACH repetition using the same beam is higher than the priority of a PRACH repetition using different beams, and the UE transmitted multiple PRACH repetitions using the same beam in a previous RACH attempt and failed to receive the RAR, the UE may transmit multiple PRACH repetitions using different beams in the next RACH attempt.

[0243] 7, if the UE fails to receive the RAR in the second RACH attempt, it may transmit multiple PRACH repetitions using the same beam and different beams in the next RACH attempt.

[0244] In the example of Figure 8, if the priority of PRACH repetitions using different beams is higher than the priority of PRACH repetitions using the same beam, and the UE transmitted multiple PRACH repetitions using different beams in a previous RACH attempt and failed to receive the RAR, the UE may transmit multiple PRACH repetitions using the same beam in the next RACH attempt.

[0245] 9, furthermore, if the RAR is not received within the second RACH attempt, the UE may transmit multiple PRACH repetitions using the same beam and different beams within the next RACH attempt.

[0246] A specific example of the operations B / D will be given below.

[0247] In the example of Figure 10, if the priority of a PRACH repetition using the same beam is higher than the priority of a PRACH repetition using different beams, and the UE transmitted multiple PRACH repetitions using the same beam in a previous RACH attempt and failed to receive the RAR, the UE may transmit multiple PRACH repetitions using the same beam and different beams in the next RACH attempt.

[0248] In the example of Figure 11, if the priority of PRACH repetitions using different beams is higher than the priority of PRACH repetitions using the same beam, and the UE transmitted multiple PRACH repetitions using different beams in a previous RACH attempt and failed to receive the RAR, the UE may transmit multiple PRACH repetitions using the same beam and different beams in the next RACH attempt.

[0249] [Options 4-9] The transmission method may be based on the UE's capabilities for beam correspondence.

[0250] If a UE does not have / report beam correspondence capability, the UE may transmit PRACH repetitions using different beams. The UE may determine whether to transmit PRACH repetitions using the same beam (for each of the different beams) based on Example 1. If it is determined to transmit PRACH repetitions using the same beam, the UE may transmit PRACH repetitions using the same beam and different beams. If it is determined not to transmit PRACH repetitions using the same beam, the UE may transmit PRACH repetitions using different beams.

[0251] If the UE has / reports beam correspondence capability, the UE may decide whether to transmit a PRACH without repetition or to transmit PRACH repetitions using the same beam based on Example 1. If it is decided to transmit PRACH repetitions using the same beam, the UE may transmit PRACH repetitions using the same beam and different beams. If it is decided not to transmit PRACH repetitions using the same beam, the UE may transmit PRACH without repetition.

[0252] A combination of at least two of options 4-1 to 4-9 may be used.

[0253] According to this embodiment, the UE can appropriately determine the PRACH transmission scheme, and when multiple repetitions are performed, the UE can appropriately determine the beams to be used for multiple repetitions.

[0254] <Supplementary Note> In the random access procedure for initial access, the UE may use different beams for multiple repetitions of the PRACH.

[0255] If the RSRP is below a threshold, the UE may use one and the same beam for multiple repetitions of the PRACH.

[0256] [Notification of Information to UE] In the above-described embodiments, any information may be notified to the UE (from a network (NW) (e.g., a base station (BS))) (in other words, reception of any information from the BS by the UE) using physical layer signaling (e.g., DCI), higher layer signaling (e.g., RRC signaling, MAC CE), a specific signal / channel (e.g., PDCCH, PDSCH, reference signal), or a combination thereof.

[0257] When the notification is performed by a MAC CE, the MAC CE may be identified by including a new Logical Channel ID (LCID) in the MAC subheader, which is not defined in existing standards.

[0258] When the notification is made by DCI, the notification may be made by a specific field of the DCI, a Radio Network Temporary Identifier (RNTI) used to scramble Cyclic Redundancy Check (CRC) bits assigned to the DCI, the format of the DCI, etc.

[0259] Furthermore, notification of any information to the UE in the above embodiments may be performed periodically, semi-persistently, or aperiodically.

[0260] [Notification of Information from UE] In the above-described embodiments, notification of any information from the UE (to the NW) (in other words, transmission / report of any information from the UE to the BS) may be performed using physical layer signaling (e.g., UCI), higher layer signaling (e.g., RRC signaling, MAC CE), a specific signal / channel (e.g., PUCCH, PUSCH, PRACH, reference signal), or a combination thereof.

[0261] When the notification is performed by a MAC CE, the MAC CE may be identified by including a new LCID, which is not defined in existing standards, in the MAC subheader.

[0262] If the notification is made by UCI, the notification may be transmitted using PUCCH or PUSCH.

[0263] Furthermore, any information in the above-described embodiments may be notified from the UE periodically, semi-persistently, or aperiodically.

[0264] [Application of Each Embodiment] At least one of the above-described embodiments may be applied when a specific condition is met. The specific condition may be defined in a standard or may be notified to a UE / BS using higher layer signaling / physical layer signaling.

[0265] At least one of the above-described embodiments may be applied only to UEs that have reported or support a particular UE capability.

[0266] The specific UE capability may indicate at least one of the following: PRACH repetition with the same beam; PRACH repetition with different beams; PRACH repetition with the same beam and different beams; Deciding whether to transmit PRACH without repetition or multiple PRACH repetitions with the same beam / different beams based on the configuration / indication by the SIB / RRC IE; Priority of PRACH repetition with the same beam, priority of PRACH repetition with different beams. The priority may be specified in the specification or configured / indicated by the SIB / RRC IE.

[0267] Furthermore, the above-mentioned specific UE capability may be a capability that is applied across all frequencies (commonly regardless of frequency), or may be a capability for each frequency (e.g., one or a combination of a cell, a band, a band combination, a BWP, a component carrier, etc.), or may be a capability for each frequency range (e.g., Frequency Range 1 (FR1), FR2, FR3, FR4, FR5, FR2-1, FR2-2), or may be a capability for each subcarrier spacing (SubCarrier Spacing (SCS)), or may be a capability for each Feature Set (FS) or Feature Set Per Component-carrier (FSPC).

[0268] Furthermore, the specific UE capability may be a capability that is applied to all duplexing methods (commonly regardless of the duplexing method), or may be a capability for each duplexing method (e.g., Time Division Duplex (TDD) or Frequency Division Duplex (FDD)).

[0269] Furthermore, at least one of the above-described embodiments may be applied when specific information related to the above-described embodiments (or performing the operations of the above-described embodiments) is configured / activated / triggered in the UE by higher layer signaling / physical layer signaling. For example, the specific information may be information indicating that the functions of the respective embodiments are enabled, any RRC parameters for a specific release (e.g., Rel. 18 / 19), etc.

[0270] If the UE does not support at least one of the specific UE capabilities or is not configured with the specific information, the UE may apply, for example, Rel. 15 / 16 behavior.

[0271] (Supplementary Notes) The following inventions are supplementary notes regarding one embodiment of the present disclosure: [Supplementary Note 1] A terminal comprising: a control unit that determines one of a first transmission scheme for transmitting a Physical Random Access Channel (PRACH) without multiple repetitions, a second transmission scheme for transmitting the multiple repetitions using the same beam, a third transmission scheme for transmitting the multiple repetitions using different beams, and a fourth transmission scheme for transmitting the multiple repetitions using the same beam and different beams; and a transmission unit that transmits one or more PRACHs using the transmission schemes. [Supplementary Note 2] The terminal according to Supplementary Note 1, wherein the controller determines the transmission scheme based on at least one of the following: an indication of the transmission scheme, a triggering method of a random access procedure, a purpose of the random access procedure, a configuration of the PRACH, a transmission counter of the PRACH, parameters of restrictions on the random access procedure, received power of a synchronization signal block and a channel state information reference signal, a priority of at least one of the second transmission scheme and the third transmission scheme, capability information related to beam correspondence, a network type, a duplexing scheme, and a frequency range. [Supplementary Note 3] The terminal according to Supplementary Note 1 or Supplementary Note 2, wherein the controller does not report both a capability of using the same beam for the multiple repetitions and a capability of using different beams for the multiple repetitions, does not assume that both of using the same beam for the multiple repetitions and using different beams for the multiple repetitions are configured, or does not apply both the same beam and different beams within one random access channel attempt. [Supplementary Note 4] The terminal according to any one of Supplementary Note 1 to Supplementary Note 3, wherein the control unit applies both the same beam and different beams within one random access channel trial.

[0272] (Wireless Communication System) The configuration of a wireless communication system according to an embodiment of the present disclosure will be described below. In this wireless communication system, communication is performed using any one of the wireless communication methods according to the above embodiments of the present disclosure or a combination thereof.

[0273] 12 is a diagram illustrating an example of a schematic configuration of a wireless communication system according to an embodiment. The wireless communication system 1 (which may be simply referred to as system 1) may be a system that realizes communication using Long Term Evolution (LTE) or 5th generation mobile communication system New Radio (5G NR) specified by the Third Generation Partnership Project (3GPP).

[0274] The wireless communication system 1 may also support dual connectivity between multiple Radio Access Technologies (RATs) (Multi-RAT Dual Connectivity (MR-DC)). MR-DC may 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)), etc.

[0275] In EN-DC, the LTE (E-UTRA) base station (eNB) is the master node (Master Node (MN)), and the NR base station (gNB) is the secondary node (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.

[0276] The wireless communication system 1 may support dual connectivity between multiple base stations within the same RAT (for example, dual connectivity in which both the MN and SN are NR base stations (gNBs) (NR-NR Dual Connectivity (NN-DC))).

[0277] The wireless communication system 1 may include a base station 11 that forms a macrocell C1 with a relatively wide coverage, and base stations 12 (12a-12c) that are located within the macrocell C1 and form small cells C2 that are smaller than the macrocell C1. A user terminal 20 may be located within at least one of the cells. The locations and numbers of the cells and user terminals 20 are not limited to the embodiment shown in the figure. Hereinafter, when there is no need to distinguish between the base stations 11 and 12, they will be collectively referred to as base station 10.

[0278] 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).

[0279] 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)). The macro cell C1 may be included in FR1, and the small cell C2 may be included in FR2. For example, FR1 may be a frequency band of 6 GHz or less (sub-6 GHz), and FR2 may be a frequency band higher than 24 GHz (above-24 GHz). Note that the frequency bands and definitions of FR1 and FR2 are not limited to these, and for example, FR1 may correspond to a higher frequency band than FR2.

[0280] 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.

[0281] The multiple base stations 10 may be connected by wire (e.g., optical fiber compliant with the Common Public Radio Interface (CPRI), an X2 interface, etc.) or wirelessly (e.g., NR communication). For example, when NR communication is used as a backhaul between the base stations 11 and 12, the base station 11 corresponding to the upper station may be called an Integrated Access Backhaul (IAB) donor, and the base station 12 corresponding to the relay station (relay) may be called an IAB node.

[0282] The base station 10 may be connected to the core network 30 directly or via another base station 10. The core network 30 may include, for example, at least one of an Evolved Packet Core (EPC), a 5G Core Network (5GCN), a Next Generation Core (NGC), and the like.

[0283] The core network 30 may include network functions (Network Functions (NF)) such as a User Plane Function (UPF), an Access and Mobility management Function (AMF), a Session Management Function (SMF), a Unified Data Management (UDM), an Application Function (AF), a Data Network (DN), a Location Management Function (LMF), and Operation, Administration and Maintenance (Management) (OAM). A single network node may provide multiple functions. Communication with an external network (e.g., the Internet) may also be performed via the DN.

[0284] The user terminal 20 may be a terminal that supports at least one of communication methods such as LTE, LTE-A, and 5G.

[0285] An Orthogonal Frequency Division Multiplexing (OFDM)-based radio access scheme may be used in the wireless communication system 1. For example, Cyclic Prefix OFDM (CP-OFDM), Discrete Fourier Transform Spread OFDM (DFT-s-OFDM), Orthogonal Frequency Division Multiple Access (OFDMA), Single Carrier Frequency Division Multiple Access (SC-FDMA), or the like may be used in at least one of the downlink (DL) and uplink (UL).

[0286] The radio access scheme may also be called a waveform. Note that in the wireless communication system 1, other radio access schemes (e.g., other single-carrier transmission schemes, other multi-carrier transmission schemes) may be used as the UL and DL radio access schemes.

[0287] In the wireless communication system 1, 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. may be used as the downlink channel.

[0288] Furthermore, in the wireless communication system 1, 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)), or the like may be used as an uplink channel.

[0289] The PDSCH transmits user data, higher layer control information, a System Information Block (SIB), etc. The PUSCH may transmit user data, higher layer control information, etc. Furthermore, the PBCH may transmit a Master Information Block (MIB).

[0290] Lower layer control information may be transmitted by the PDCCH. The lower layer control information may include, for example, Downlink Control Information (DCI) including scheduling information for at least one of the PDSCH and the PUSCH.

[0291] Note that the DCI for scheduling the PDSCH may be referred to as a DL assignment, a DL DCI, etc., and the DCI for scheduling the PUSCH may be referred to as a UL grant, a UL DCI, etc. Note that the PDSCH may be replaced with DL data, and the PUSCH may be replaced with UL data.

[0292] A control resource set (CORESET) and a search space may be used to detect the PDCCH. The CORESET corresponds to resources for searching for DCI. The search space corresponds to a search region and a search method for PDCCH candidates. One CORESET may be associated with one or more search spaces. The UE may monitor the CORESET associated with a certain search space based on the search space configuration.

[0293] One search space may correspond to PDCCH candidates corresponding to one or more aggregation levels. One or more search spaces may be referred to as a search space set. Note that the terms "search space," "search space set," "search space configuration," "search space set configuration," "CORESET," "CORESET configuration," and the like in the present disclosure may be read interchangeably.

[0294] The PUCCH may transmit uplink control information (UCI) including at least one of channel state information (CSI), delivery confirmation information (which may be called, for example, Hybrid Automatic Repeat reQuest ACKnowledgement (HARQ-ACK), ACK / NACK, etc.), and scheduling request (SR). The PRACH may transmit a random access preamble for establishing a connection with a cell.

[0295] In the present disclosure, downlink, uplink, etc. may be expressed without adding "link." Also, various channels may be expressed without adding "Physical" to the beginning.

[0296] In the wireless communication system 1, a synchronization signal (SS), a downlink reference signal (DL-RS), etc. may be transmitted. In the wireless communication system 1, as the DL-RS, a cell-specific reference signal (CRS), a channel state information reference signal (CSI-RS), a demodulation reference signal (DMRS), a positioning reference signal (PRS), a phase tracking reference signal (PTRS), etc. may be transmitted.

[0297] The synchronization signal may be, for example, at least one of a Primary Synchronization Signal (PSS) and a Secondary Synchronization Signal (SSS). A signal block including an SS (PSS, SSS) and a PBCH (and a DMRS for the PBCH) may be referred to as an SS / PBCH block, an SS Block (SSB), or the like. Note that the SS, SSB, and the like may also be referred to as a reference signal.

[0298] Furthermore, in the wireless communication system 1, a sounding reference signal (SRS), a demodulation reference signal (DMRS), or the like may be transmitted as an uplink reference signal (UL-RS). Note that the DMRS may also be called a user equipment-specific reference signal (UE-specific reference signal).

[0299] (Base Station) Fig. 13 is a diagram showing an example of the configuration of a base station according to an embodiment. The base station 10 includes a control unit 110, a transceiver unit 120, a transceiver antenna 130, and a transmission line interface 140. Note that the base station may include one or more of each of the control unit 110, the transceiver unit 120, the transceiver antenna 130, and the transmission line interface 140.

[0300] In this example, the functional blocks of the characteristic parts of the present embodiment are mainly shown, and it may be assumed that the base station 10 also has other functional blocks necessary for wireless communication. Some of the processing of each unit described below may be omitted.

[0301] The control unit 110 performs overall control of the base station 10. The control unit 110 can be configured from a controller, a control circuit, and the like that are explained based on common understanding in the technical field to which the present disclosure relates.

[0302] The control unit 110 may control signal generation, scheduling (e.g., resource allocation, mapping), etc. The control unit 110 may control transmission and reception using the transceiver unit 120, the transceiver antenna 130, and the transmission path interface 140, measurement, etc. The control unit 110 may generate data, control information, sequences, etc. to be transmitted as signals, and transfer them to the transceiver unit 120. The control unit 110 may perform call processing (setting up, releasing, etc.) of communication channels, status management of the base station 10, management of radio resources, etc.

[0303] The transceiver unit 120 may include a baseband unit 121, a radio frequency (RF) unit 122, and a measurement unit 123. The baseband unit 121 may include a transmission processing unit 1211 and a reception processing unit 1212. The transceiver unit 120 may be configured with a transmitter / receiver, an RF circuit, a baseband circuit, a filter, a phase shifter, a measurement circuit, a transceiver circuit, etc., which are described based on common understanding in the technical field related to the present disclosure.

[0304] The transmitting / receiving unit 120 may be configured as an integrated transmitting / receiving unit, or may be configured from a transmitting unit and a receiving unit. The transmitting unit may be configured from a transmission processing unit 1211 and an RF unit 122. The receiving unit may be configured from a reception processing unit 1212, the RF unit 122, and a measurement unit 123.

[0305] The transmitting and receiving antenna 130 can be configured from an antenna described based on common understanding in the technical field to which the present disclosure relates, such as an array antenna.

[0306] The transceiver 120 may transmit the above-mentioned downlink channel, synchronization signal, downlink reference signal, etc. The transceiver 120 may receive the above-mentioned uplink channel, uplink reference signal, etc.

[0307] The transceiver 120 may form at least one of the transmit beam and the receive beam using digital beamforming (e.g., precoding), analog beamforming (e.g., phase rotation), or the like.

[0308] The transmitter / receiver unit 120 (transmission processing unit 1211) may perform Packet Data Convergence Protocol (PDCP) layer processing, Radio Link Control (RLC) layer processing (e.g., RLC retransmission control), Medium Access Control (MAC) layer processing (e.g., HARQ retransmission control), etc. on data, control information, etc. obtained from the control unit 110, and generate a bit string to be transmitted.

[0309] The transmitter / receiver unit 120 (transmission processing unit 1211) may perform transmission processing such as channel coding (which may include error correction coding), modulation, mapping, filtering, Discrete Fourier Transform (DFT) processing (if necessary), Inverse Fast Fourier Transform (IFFT) processing, precoding, and digital-to-analog conversion on the bit string to be transmitted, and output a baseband signal.

[0310] The transceiver unit 120 (RF unit 122) may perform modulation, filtering, amplification, etc. on the baseband signal to a radio frequency band, and transmit the radio frequency band signal via the transceiver antenna 130.

[0311] On the other hand, the transceiver unit 120 (RF unit 122) may perform amplification, filtering, demodulation to a baseband signal, etc. on the radio frequency band signal received by the transceiver antenna 130.

[0312] The transceiver 120 (reception processing unit 1212) may apply reception processing such as analog-to-digital conversion, Fast Fourier Transform (FFT) processing, Inverse Discrete Fourier Transform (IDFT) processing (if necessary), filtering, demapping, demodulation, decoding (which may include error correction decoding), MAC layer processing, RLC layer processing, and PDCP layer processing to the acquired baseband signal, thereby acquiring user data, etc.

[0313] The transceiver 120 (measurement unit 123) may perform measurements on the received signal. For example, the measurement unit 123 may perform Radio Resource Management (RRM) measurements, Channel State Information (CSI) measurements, etc. based on the received signal. The measurement unit 123 may measure received power (e.g., Reference Signal Received Power (RSRP)), received quality (e.g., Reference Signal Received Quality (RSRQ), Signal to Interference plus Noise Ratio (SINR), Signal to Noise Ratio (SNR)), signal strength (e.g., Received Signal Strength Indicator (RSSI)), propagation path information (e.g., CSI), etc. The measurement results may be output to the control unit 110.

[0314] The transmission path interface 140 may transmit and receive signals (backhaul signaling) between devices included in the core network 30 (e.g., network nodes that provide NF), other base stations 10, etc., and may acquire and transmit user data (user plane data), control plane data, etc. for the user terminal 20.

[0315] The transmitting section and receiving section of the base station 10 in the present disclosure may be configured by at least one of the transmitting / receiving section 120, the transmitting / receiving antenna 130, and the transmission path interface 140.

[0316] The control unit 110 may determine one of a first transmission scheme for transmitting a Physical Random Access Channel (PRACH) without multiple repetitions, a second transmission scheme for transmitting the multiple repetitions using the same beam, a third transmission scheme for transmitting the multiple repetitions using different beams, and a fourth transmission scheme for transmitting the multiple repetitions using the same beam and different beams. The transceiver unit 120 may receive one or more PRACHs using the transmission schemes.

[0317] (User Terminal) Fig. 14 is a diagram showing an example of the configuration of a user terminal according to one embodiment. The user terminal 20 includes a control unit 210, a transceiver unit 220, and a transceiver antenna 230. Note that the user terminal 20 may include one or more of each of the control unit 210, the transceiver unit 220, and the transceiver antenna 230.

[0318] In this example, the functional blocks of the characteristic parts of the present embodiment are mainly shown, and it may be assumed that the user terminal 20 also has other functional blocks necessary for wireless communication. Some of the processing of each unit described below may be omitted.

[0319] The control unit 210 performs overall control of the user terminal 20. The control unit 210 can be configured from a controller, a control circuit, etc., which are described based on common understanding in the technical field to which the present disclosure relates.

[0320] The control unit 210 may control signal generation, mapping, etc. The control unit 210 may control transmission and reception, measurement, etc. using the transceiver unit 220 and the transceiver antenna 230. The control unit 210 may generate data, control information, sequences, etc. to be transmitted as signals and transfer them to the transceiver unit 220.

[0321] The transceiver unit 220 may include a baseband unit 221, an RF unit 222, and a measurement unit 223. The baseband unit 221 may include a transmission processing unit 2211 and a reception processing unit 2212. The transceiver unit 220 may be configured with a transmitter / receiver, an RF circuit, a baseband circuit, a filter, a phase shifter, a measurement circuit, a transceiver circuit, etc., which are described based on common understanding in the technical field related to the present disclosure.

[0322] The transmitting / receiving unit 220 may be configured as an integrated transmitting / receiving unit, or may be composed of a transmitting unit and a receiving unit. The transmitting unit may be composed of a transmission processing unit 2211 and an RF unit 222. The receiving unit may be composed of a reception processing unit 2212, an RF unit 222, and a measurement unit 223.

[0323] The transmitting / receiving antenna 230 can be configured from an antenna described based on common understanding in the technical field to which the present disclosure relates, such as an array antenna.

[0324] The transceiver 220 may receive the above-mentioned downlink channel, synchronization signal, downlink reference signal, etc. The transceiver 220 may transmit the above-mentioned uplink channel, uplink reference signal, etc.

[0325] The transceiver unit 220 may form at least one of the transmit beam and the receive beam using digital beamforming (e.g., precoding), analog beamforming (e.g., phase rotation), or the like.

[0326] The transceiver unit 220 (transmission processing unit 2211) may perform PDCP layer processing, RLC layer processing (e.g., RLC retransmission control), MAC layer processing (e.g., HARQ retransmission control), etc. on data, control information, etc. obtained from the control unit 210, and generate a bit string to be transmitted.

[0327] The transmitter / receiver unit 220 (transmission processing unit 2211) may perform transmission processing such as channel coding (which may include error correction coding), modulation, mapping, filtering, DFT processing (if necessary), IFFT processing, precoding, and digital-to-analog conversion on the bit string to be transmitted, and output a baseband signal.

[0328] Whether or not to apply DFT processing may be based on the setting of transform precoding. When transform precoding is enabled for a certain channel (e.g., PUSCH), the transceiver unit 220 (transmission processing unit 2211) may perform DFT processing as the transmission processing to transmit the channel using a DFT-s-OFDM waveform, and if not, it may not be necessary to perform DFT processing as the transmission processing.

[0329] The transceiver unit 220 (RF unit 222) may perform modulation, filtering, amplification, etc. on the baseband signal to a radio frequency band, and transmit the radio frequency band signal via the transceiver antenna 230.

[0330] On the other hand, the transceiver unit 220 (RF unit 222) may perform amplification, filtering, demodulation to a baseband signal, etc. on the radio frequency band signal received by the transceiver antenna 230.

[0331] The transceiver unit 220 (reception processing unit 2212) may apply reception processing such as analog-to-digital conversion, FFT processing, IDFT processing (if necessary), filtering, demapping, demodulation, decoding (which may include error correction decoding), MAC layer processing, RLC layer processing, and PDCP layer processing to the acquired baseband signal, and acquire user data, etc.

[0332] The transceiver 220 (measurement unit 223) may perform measurements on the received signal. For example, the measurement unit 223 may perform RRM measurements, CSI measurements, etc. based on the received signal. The measurement unit 223 may 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 be output to the control unit 210.

[0333] The transmitting unit and receiving unit of the user terminal 20 in the present disclosure may be configured by at least one of the transmitting / receiving unit 220 and the transmitting / receiving antenna 230.

[0334] The control unit 210 may determine one of a first transmission scheme for transmitting a Physical Random Access Channel (PRACH) without multiple repetitions, a second transmission scheme for transmitting the multiple repetitions using the same beam, a third transmission scheme for transmitting the multiple repetitions using different beams, and a fourth transmission scheme for transmitting the multiple repetitions using the same beam and different beams. The transceiver unit 220 may transmit one or more PRACHs using the transmission schemes.

[0335] The control unit 210 may determine the transmission scheme based on at least one of the following: an instruction on the transmission scheme, a triggering method for the random access procedure, a purpose of the random access procedure, a setting of the PRACH, a transmission counter of the PRACH, a parameter of a restriction on the random access procedure, received power of a synchronization signal block and a channel state information reference signal, a priority of at least one of the second transmission scheme and the third transmission scheme, capability information regarding beam correspondence, a network type, a duplexing scheme, and a frequency range.

[0336] The control unit 210 may not report both the ability to use the same beam for the multiple repetitions and the ability to use different beams for the multiple repetitions, or may not assume that it is configured to use both the same beam for the multiple repetitions and different beams for the multiple repetitions, or may not apply both the same beam and different beams within one random access channel attempt.

[0337] The controller 210 may apply both the same beam and different beams within a single random access channel trial.

[0338] (Hardware Configuration) Note that the block diagrams used to explain the above embodiments show functional blocks. These functional blocks (components) are realized by any combination of at least one of hardware and software. Furthermore, the method for realizing each functional block is not particularly limited. That is, each functional block may be realized using a single device that is physically or logically coupled, or may be realized using two or more physically or logically separated devices that are directly or indirectly connected (for example, using wires, wirelessly, etc.) and these multiple devices. The functional block may be realized by combining software with the single device or the multiple devices.

[0339] Here, the functions include, but are not limited to, judgment, determination, judgment, calculation, computation, processing, derivation, investigation, search, confirmation, reception, transmission, output, access, resolution, selection, election, establishment, comparison, assumption, expectation, deeming, broadcasting, notifying, communicating, forwarding, configuring, reconfiguring, allocating, mapping, and assignment. For example, a functional block (component) that performs transmission may be called a transmitting unit, transmitter, etc. As described above, the implementation method of each is not particularly limited.

[0340] For example, a base station, a user terminal, etc. according to an embodiment of the present disclosure may function as a computer that performs processing of the wireless communication method of the present disclosure. Fig. 15 is a diagram illustrating an example of the hardware configuration of a base station and a user terminal according to an embodiment. The above-described base station 10 and user terminal 20 may be physically configured as a computer device including a processor 1001, a memory 1002, a storage 1003, a communication device 1004, an input device 1005, an output device 1006, a bus 1007, etc.

[0341] In the present disclosure, the terms apparatus, circuit, device, section, unit, etc. may be used interchangeably. The hardware configurations of the base station 10 and the user terminal 20 may be configured to include one or more of the devices shown in the drawings, or may be configured to exclude some of the devices.

[0342] For example, although only one processor 1001 is shown, there may be multiple processors. Furthermore, processing may be performed by one processor, or processing may be performed by two or more processors simultaneously, serially, or in other ways. Furthermore, processor 1001 may be implemented by one or more chips.

[0343] Each function in the base station 10 and the user terminal 20 is realized, for example, by loading specified software (programs) onto hardware such as a processor 1001 and a memory 1002, causing the processor 1001 to perform calculations, control communication via the communication device 1004, and control at least one of reading and writing data in the memory 1002 and the storage 1003.

[0344] The processor 1001, for example, runs an operating system to control the entire computer. The processor 1001 may be configured as a central processing unit (CPU) including an interface with peripheral devices, a control device, an arithmetic unit, a register, etc. For example, at least a part of the above-mentioned control unit 110 (210), transceiver unit 120 (220), etc. may be realized by the processor 1001.

[0345] The processor 1001 also reads programs (program codes), 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 in accordance with these. The programs used are those that cause a computer to execute at least some of the operations described in the above-described embodiments. For example, the control unit 110 (210) may be implemented by a control program stored in the memory 1002 and running on the processor 1001, and the other functional blocks may be implemented in a similar manner.

[0346] The memory 1002 is a computer-readable recording medium and may be configured by at least one of, for example, Read Only Memory (ROM), Erasable Programmable ROM (EPROM), Electrically EEPROM (EEPROM), Random Access Memory (RAM), or other suitable storage medium. The memory 1002 may also be referred to as a register, cache, main memory, etc. The memory 1002 may store executable programs (program codes), software modules, etc. for implementing a wireless communication method according to an embodiment of the present disclosure.

[0347] Storage 1003 is a computer-readable recording medium and may be composed of at least one of, for example, a flexible disk, a floppy disk, a magneto-optical disk (e.g., a compact disc (e.g., a Compact Disc ROM (CD-ROM)), a digital versatile disc, a Blu-ray disc), a removable disk, a hard disk drive, a smart card, a flash memory device (e.g., a card, a stick, a key drive), a magnetic stripe, a database, a server, or other suitable storage medium. Storage 1003 may also be referred to as an auxiliary storage device.

[0348] The communication device 1004 is hardware (transmission / reception device) for communicating between computers via at least one of a wired network and a wireless network, and is also referred to as, for example, a network device, a network controller, a network card, or a communication module. The communication device 1004 may be configured to include a high-frequency switch, a duplexer, a filter, a frequency synthesizer, etc. to realize at least one of frequency division duplex (FDD) and time division duplex (TDD). For example, the above-mentioned transmission / reception unit 120 (220), transmission / reception antenna 130 (230), etc. may be realized by the communication device 1004. The transmission / reception unit 120 (220) may be implemented as a transmission unit 120a (220a) and a reception unit 120b (220b) that are physically or logically separated.

[0349] The input device 1005 is an input device (e.g., a keyboard, a mouse, a microphone, a switch, a button, a sensor, etc.) that accepts input from the outside. The output device 1006 is an output device (e.g., a display, a speaker, a light emitting diode (LED) lamp, etc.) that outputs to the outside. Note that the input device 1005 and the output device 1006 may be integrated into one device (e.g., a touch panel).

[0350] Furthermore, each device, such as the processor 1001 and the memory 1002, is connected by a bus 1007 for communicating information. The bus 1007 may be configured using a single bus, or may be configured using different buses between each device.

[0351] Furthermore, the base station 10 and the user terminal 20 may 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 some or all of the functional blocks may be realized using this hardware. For example, the processor 1001 may be implemented using at least one of these pieces of hardware.

[0352] (Modifications) Note that terms described in the present disclosure and terms necessary for understanding the present disclosure may be replaced with terms having the same or similar meanings. For example, a channel, a symbol, and a signal (signal or signaling) may be interchangeable. A signal may also be a message. A reference signal may be abbreviated as RS, and may also be called a pilot, pilot signal, etc. depending on the applicable standard. A component carrier (CC) may also be called a cell, frequency carrier, carrier frequency, etc.

[0353] A radio frame may be composed of one or more periods (frames) in the time domain. Each of the one or more periods (frames) constituting a radio frame may be called a subframe. Furthermore, a subframe may be composed of one or more slots in the time domain. A subframe may have a fixed time length (e.g., 1 ms) that is independent of numerology.

[0354] Here, the numerology may be a communication parameter applied to at least one of transmission and reception of a signal or channel, and may indicate at least one of, for example, Subcarrier Spacing (SCS), bandwidth, symbol length, cyclic prefix length, Transmission Time Interval (TTI), number of symbols per TTI, radio frame structure, specific filtering performed by a transceiver in the frequency domain, and specific windowing performed by a transceiver in the time domain.

[0355] A slot may be composed of one or more symbols (such as an Orthogonal Frequency Division Multiplexing (OFDM) symbol or a Single Carrier Frequency Division Multiple Access (SC-FDMA) symbol) in the time domain. A slot may also be a time unit based on numerology.

[0356] A slot may include multiple minislots. Each minislot may consist of one or multiple symbols in the time domain. A minislot may also be called a subslot. A minislot may consist of fewer symbols than a slot. A PDSCH (or PUSCH) transmitted in a time unit larger than a minislot may be called PDSCH (PUSCH) mapping type A. A PDSCH (or PUSCH) transmitted using a minislot may be called PDSCH (PUSCH) mapping type B.

[0357] A radio frame, a subframe, a slot, a minislot, and a symbol all represent time units for transmitting signals. The radio frame, the subframe, the slot, the minislot, and the symbol may be referred to by other names corresponding to the radio frame, the subframe, the slot, the minislot, and the symbol. Note that the time units such as a frame, a subframe, a slot, a minislot, and a symbol in the present disclosure may be interchangeable.

[0358] For example, one subframe may be referred to as a TTI, or multiple consecutive subframes may be referred to as a TTI, or one slot or one minislot may be referred to as a TTI. That is, at least one of the subframe and the TTI may 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. Note that the unit representing the TTI may be called a slot, minislot, etc. instead of a subframe.

[0359] Here, TTI refers to, for example, the smallest time unit for scheduling in wireless communication. For example, in an LTE system, a base station performs scheduling to allocate radio resources (such as frequency bandwidth and transmission power that can be used by each user terminal) to each user terminal in TTI units. Note that the definition of TTI is not limited to this.

[0360] The TTI may be a transmission time unit for a channel-encoded data packet (transport block), a code block, a code word, etc., or may be a processing unit for scheduling, link adaptation, etc. When a TTI is given, the time interval (e.g., the number of symbols) to which a transport block, a code block, a code word, etc. is actually mapped may be shorter than the TTI.

[0361] When one slot or one minislot is called a TTI, one or more TTIs (i.e., one or more slots or one or more minislots) may be the minimum time unit for scheduling. Also, the number of slots (minislots) constituting the minimum time unit for scheduling may be controlled.

[0362] A TTI having a time length of 1 ms may be called a regular TTI (TTI in 3GPP Rel. 8-12), normal TTI, long TTI, regular subframe, normal subframe, long subframe, slot, etc. A TTI shorter than a regular TTI may be called a shortened TTI, short TTI, partial or fractional TTI, shortened subframe, short subframe, minislot, subslot, slot, etc.

[0363] In addition, a long TTI (e.g., a normal TTI, a subframe, etc.) may be interpreted as a TTI having a time length of more than 1 ms, and a short TTI (e.g., a shortened TTI, etc.) may be interpreted as a TTI having a TTI length shorter than the TTI length of a long TTI and greater than or equal to 1 ms.

[0364] A resource block (RB) is a resource allocation unit in the time domain and the frequency domain, and may include one or more consecutive subcarriers in the frequency domain. The number of subcarriers included in an RB may be the same regardless of numerology, for example, 12. The number of subcarriers included in an RB may be determined based on numerology.

[0365] In addition, an RB may include one or more symbols in the time domain and may have a length of one slot, one minislot, one subframe, or one TTI, each of which may be composed of one or more resource blocks.

[0366] In addition, one or more RBs may be referred to as a physical resource block (PRB), a sub-carrier group (SCG), a resource element group (REG), a PRB pair, an RB pair, etc.

[0367] 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.

[0368] A Bandwidth Part (BWP), which may also be referred to as a partial bandwidth, may represent a subset of contiguous common resource blocks (RBs) for a given numerology on a given carrier, where the common RBs may be identified by their index relative to a Common Reference Point of the carrier. PRBs may be defined in a BWP and numbered within the BWP.

[0369] The BWP may include a UL BWP (BWP for UL) and a DL BWP (BWP for DL). One or more BWPs may be configured for a UE within one carrier.

[0370] At least one of the configured BWPs may be active, and the UE may not expect to transmit or receive a given signal / channel outside the active BWP. Note that the terms "cell," "carrier," etc. in this disclosure may be read as "BWP."

[0371] The above-described structures of radio frames, subframes, slots, minislots, symbols, etc. are merely examples. For example, the number of subframes included in a radio frame, the number of slots per subframe or radio frame, the number of minislots included in a slot, the number of symbols and RBs included in a slot or minislot, the number of subcarriers included in an RB, the number of symbols in a TTI, the symbol length, the cyclic prefix (CP) length, etc. may be changed in various ways.

[0372] Furthermore, the information, parameters, etc. described in the present disclosure may be expressed using absolute values, may be expressed using relative values ​​from a predetermined value, or may be expressed using other corresponding information. For example, a radio resource may be indicated by a predetermined index.

[0373] The names used for parameters and the like in this disclosure are not intended to be limiting in any way. Furthermore, the mathematical expressions and the like using these parameters may differ from those explicitly disclosed in this disclosure. The various channels (PUCCH, PDCCH, etc.) and information elements may 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 way.

[0374] The information, signals, etc. described in this disclosure may be represented using any of a variety of different technologies. For example, data, instructions, commands, information, signals, bits, symbols, chips, etc. that may be referred to throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or magnetic particles, optical fields or photons, or any combination thereof.

[0375] Furthermore, information, signals, etc. may be output from a higher layer to a lower layer and / or from a lower layer to a higher layer. Information, signals, etc. may be input / output via multiple network nodes.

[0376] Input and output information, signals, etc. may be stored in a specific location (for example, memory) or may be managed using a management table. Input and output information, signals, etc. may be overwritten, updated, or added. Output information, signals, etc. may be deleted. Input information, signals, etc. may be transmitted to another device.

[0377] The notification of information is not limited to the aspects / embodiments described in the present disclosure, and may be performed using other methods. For example, the notification of information in the present disclosure may be performed by physical layer signaling (e.g., Downlink Control Information (DCI) and Uplink Control Information (UCI)), higher layer signaling (e.g., Radio Resource Control (RRC) signaling, broadcast information (Master Information Block (MIB) and System Information Block (SIB)), Medium Access Control (MAC) signaling), other signals, or a combination thereof.

[0378] Note that the physical layer signaling may be referred to as Layer 1 / Layer 2 (L1 / L2) control information (L1 / L2 control signal), L1 control information (L1 control signal), etc. Furthermore, the RRC signaling may be referred to as an RRC message, such as an RRC Connection Setup message or an RRC Connection Reconfiguration message. Furthermore, the MAC signaling may be notified using, for example, a MAC Control Element (CE).

[0379] Furthermore, notification of specified information (e.g., notification that "it is X") is not limited to explicit notification, but may be made implicitly (e.g., by not notifying the specified information or by notifying other information).

[0380] The determination may be made by a value represented by one bit (0 or 1), by a Boolean value represented by true or false, or by a comparison of numerical values ​​(e.g., comparison with a predetermined value).

[0381] Software shall be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software modules, applications, software applications, software packages, routines, subroutines, objects, executable files, threads of execution, procedures, functions, etc., whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise.

[0382] Software, instructions, information, etc. may also be transmitted or received over a transmission medium. For example, if software is transmitted from a website, server, or other remote source using wired technologies (such as coaxial cable, fiber optic cable, twisted pair, Digital Subscriber Line (DSL)), and / or wireless technologies (such as infrared, microwave), these wired and / or wireless technologies are included within the definition of transmission media.

[0383] As used in this disclosure, the terms "system" and "network" may be used interchangeably. A "network" may refer to devices included in the network (e.g., base stations).

[0384] 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," "panel," etc. may be used interchangeably.

[0385] In the present disclosure, terms such as "base station (BS)," "radio base station," "fixed station," "NodeB," "eNB (eNodeB)," "gNB (gNodeB)," "access point," "transmission point (TP)," "reception point (RP)," "transmission / reception point (TRP)," "panel," "cell," "sector," "cell group," "carrier," "component carrier," etc. may be used interchangeably. Base stations may also be referred to by terms such as macrocell, small cell, femtocell, picocell, etc.

[0386] A base station can accommodate one or more (e.g., three) cells. When a base station accommodates multiple cells, the overall coverage area of ​​the base station can be partitioned into multiple smaller areas, and each smaller area can be provided with communication service by a base station subsystem (e.g., a small indoor base station (Remote Radio Head (RRH))). The terms "cell" or "sector" refer to part or all of the coverage area of ​​a base station and / or base station subsystem that provides communication service within that coverage.

[0387] In the present disclosure, a base station transmitting information to a terminal may be interpreted as the base station instructing the terminal to control / operate based on the information.

[0388] In this disclosure, the terms "Mobile Station (MS)," "user terminal," "User Equipment (UE)," "terminal," etc. may be used interchangeably.

[0389] 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, handset, user agent, mobile client, client, or some other suitable terminology.

[0390] At least one of the base station and the mobile station may be called a transmitting device, a receiving device, a wireless communication device, etc. Note that at least one of the base station and the mobile station may be a device mounted on a moving object, the moving object itself, etc.

[0391] The mobile body is a movable object that can move at any speed and naturally includes cases where the mobile body is stationary. Examples of the mobile body include, but are not limited to, vehicles, transport vehicles, automobiles, motorcycles, bicycles, connected cars, excavators, bulldozers, wheel loaders, dump trucks, forklifts, trains, buses, handcars, rickshaws, ships and other watercraft, airplanes, rockets, satellites, drones, multicopters, quadcopters, balloons, and objects mounted thereon. The mobile body may also be a mobile body that moves autonomously based on an operation command.

[0392] The mobile object may be a vehicle (e.g., a car, an airplane, etc.), an unmanned mobile object (e.g., a drone, an autonomous vehicle, etc.), or a robot (manned or unmanned). Note that at least one of the base station and the mobile station may also include devices that do 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.

[0393] 16 is a diagram showing an example of a vehicle according to an embodiment. The 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, axles 48, an electronic control unit 49, various sensors (including a current sensor 50, an RPM 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.

[0394] The drive unit 41 is configured with at least one of an engine, a motor, and a hybrid of an engine and a motor, for example. The steering unit 42 includes at least a steering wheel (also called a handle) and is configured to steer at least one of the front wheels 46 and the rear wheels 47 based on the operation of the steering wheel operated by a user.

[0395] The electronic control unit 49 is composed of a microprocessor 61, memory (ROM, RAM) 62, and a communication port (for example, an input / output (IO) port) 63. Signals are input to the electronic control unit 49 from various sensors 50-58 provided in the vehicle. The electronic control unit 49 may also be called an Electronic Control Unit (ECU).

[0396] The signals from the various sensors 50-58 include a current signal from a current sensor 50 that senses the current of the motor, a rotation speed signal of the front wheels 46 / rear wheels 47 obtained by a rotation speed sensor 51, an air pressure signal of the front wheels 46 / rear wheels 47 obtained by an air pressure sensor 52, a vehicle speed signal obtained by a vehicle speed sensor 53, an acceleration signal obtained by an acceleration sensor 54, a depression amount signal of the accelerator pedal 43 obtained by an accelerator pedal sensor 55, a depression amount signal of the brake pedal 44 obtained by a brake pedal sensor 56, an operation signal of the shift lever 45 obtained by a shift lever sensor 57, and a detection signal for detecting obstacles, vehicles, pedestrians, etc. obtained by an object detection sensor 58.

[0397] The information service unit 59 is composed of various devices, such as a car navigation system, an audio system, speakers, a display, a television, and a radio, for providing (outputting) various information such as driving information, traffic information, and entertainment information, and one or more ECUs for controlling these devices. The information service unit 59 uses information acquired from external devices via the communication module 60 or the like to provide various information / services (e.g., multimedia information / multimedia services) to the occupants of the vehicle 40.

[0398] The information service unit 59 may include input devices (e.g., keyboards, mice, microphones, switches, buttons, sensors, touch panels, etc.) that accept input from the outside, and may also include output devices (e.g., displays, speakers, LED lamps, touch panels, etc.) that output to the outside.

[0399] The driving assistance system unit 64 includes various devices for providing functions to prevent accidents and reduce the driver's driving burden, such as millimeter-wave radar, Light Detection and Ranging (LiDAR), cameras, positioning locators (e.g., Global Navigation Satellite System (GNSS)), map information (e.g., High Definition (HD) maps, Autonomous Vehicle (AV) maps), gyro systems (e.g., Inertial Measurement Units (IMUs), Inertial Navigation Systems (INSs)), artificial intelligence (AI) chips, and AI processors, as well as one or more ECUs that control these devices. The driving assistance system unit 64 also transmits and receives various information via the communication module 60 to realize driving assistance functions or autonomous driving functions.

[0400] 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 to and from 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, the microprocessor 61 and memory (ROM, RAM) 62 in the electronic control unit 49, and the various sensors 50-58, which are provided in the vehicle 40.

[0401] The communication module 60 is a communication device that can be controlled by the microprocessor 61 of the electronic control unit 49 and can communicate with an external device. For example, it transmits and receives various information to and from the external device via wireless communication. The communication module 60 may be located either inside or outside the electronic control unit 49. The external device may be, for example, the base station 10 or the user terminal 20 described above. Furthermore, the communication module 60 may be, for example, at least one of the base station 10 and the user terminal 20 described above (or may function as at least one of the base station 10 and the user terminal 20).

[0402] The communication module 60 may transmit at least one of signals from the above-mentioned various sensors 50-58 input to the electronic control unit 49, information obtained based on the signals, and information based on input from the outside (user) obtained via the information service unit 59 to an external device via wireless communication. The electronic control unit 49, the various sensors 50-58, the information service unit 59, etc. may be referred to as input units that accept input. For example, the PUSCH transmitted by the communication module 60 may include information based on the above-mentioned input.

[0403] The communication module 60 receives various information (traffic information, traffic signal information, vehicle distance information, etc.) transmitted from an external device and displays it on an information service unit 59 provided in the vehicle. The information service unit 59 may also be called an output unit that outputs information (for example, outputs information to a device such as a display or speaker based on the PDSCH received by the communication module 60 (or data / information decoded from the PDSCH)).

[0404] 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 may 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 provided in the vehicle 40.

[0405] Furthermore, a base station in the present disclosure may be read as a user terminal. For example, the aspects / embodiments of the present disclosure may be applied to a configuration in which communication between a base station and a user terminal is replaced with communication between multiple user terminals (which may be called, for example, Device-to-Device (D2D) or Vehicle-to-Everything (V2X)). In this case, the user terminal 20 may be configured to have the functions of the base station 10 described above. Furthermore, terms such as "uplink" and "downlink" may be read as terms corresponding to terminal-to-terminal communication (for example, "sidelink"). For example, terms such as an uplink channel and a downlink channel may be read as a sidelink channel.

[0406] Similarly, the user terminal in the present disclosure may be read as a base station, in which case the base station 10 may be configured to have the functions of the user terminal 20 described above.

[0407] In the present disclosure, an operation described as being performed by a base station may be performed by its upper node in some cases. It is apparent that in a network including one or more network nodes having 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 (such as, but not limited to, a Mobility Management Entity (MME), a Serving-Gateway (S-GW), etc.), or a combination thereof.

[0408] Each aspect / embodiment described in this disclosure may be used alone, in combination, or switched depending on the implementation. Furthermore, the order of the processing procedures, sequences, flowcharts, etc. of each aspect / embodiment described in this disclosure may be changed unless inconsistent. For example, the methods described in this disclosure present elements of various steps using an example order, and are not limited to the particular order presented.

[0409] Each aspect / embodiment described in the present disclosure may be a technology other than 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 decimal number)), Future Radio Access (FRA), New-Radio Access Technology (RAT), New Radio (NR), New radio access (NX), Future generation radio access (FX), Global System for Mobile communications (GSM (registered trademark)), CDMA2000, Ultra Mobile Broadband (UMB), IEEE 802.11 (Wi-Fi (registered trademark)), IEEE 802.16 (WiMAX (registered trademark)), IEEE 802.17 (WiMAX (registered trademark)), IEEE 802.19 (WiMAX (registered trademark)), IEEE 802.20 (WiMAX (registered trademark)), IEEE 802.21 (Wi-Fi (registered trademark)), IEEE 802.22 (WiMAX (registered trademark)), IEEE 802.23 (WiMAX (registered trademark)), IEEE 802.24 (WiMAX (registered trademark)), IEEE 802.25 (WiMAX (registered trademark)), IEEE 802.26 (WiMAX (registered trademark)), IEEE 802.27 (WiMAX (registered trademark)), IEEE 802.28 (WiMAX (registered trademark)), IEEE 802.29 (WiMAX (registered trademark)), IEEE 802.30 (WiMAX (registered trademark)), IEEE 802.31 (Wi-Fi (registered trademark)), IEEE 802.32 (WiMAX (registered trademark)), IEEE 802.33 (WiMAX (registered trademark)), IEEE 802. The present invention may be applied to systems that use IEEE 802.20, Ultra-WideBand (UWB), Bluetooth (registered trademark), or other suitable wireless communication methods, or to next-generation systems that are expanded, modified, created, or defined based on these. Furthermore, the present invention may be applied to a combination of multiple systems (e.g., a combination of LTE or LTE-A and 5G).

[0410] As used in this disclosure, the phrase "based on" does not mean "based only on," unless expressly stated otherwise. In other words, the phrase "based on" means both "based only on" and "based at least on."

[0411] As used in this disclosure, any reference to an element using a designation such as "first," "second," etc. does not generally limit the quantity or order of those elements. These designations may be used in this disclosure as a convenient method of distinguishing between two or more elements. Thus, a reference to a first and a second element does not imply that only two elements may be employed or that the first element must in some way precede the second element.

[0412] The term "determining" as used in this disclosure may encompass a wide variety of actions. For example, "determining" may be considered to be judging, calculating, computing, processing, deriving, investigating, looking up, search, inquiry (e.g., looking up in a table, database, or another data structure), ascertaining, etc.

[0413] Additionally, "determining" may be considered to be "determining" receiving (e.g., receiving information), transmitting (e.g., sending information), input, output, accessing (e.g., accessing data in memory), etc.

[0414] Also, "determination" may be considered to be "deciding" resolving, selecting, choosing, establishing, comparing, etc. In other words, "determination" may be considered to be "deciding" some action.

[0415] Furthermore, "judgment (decision)" may be read as "assuming," "expecting," "considering," or the like.

[0416] The "maximum transmit power" in this disclosure may mean the maximum value of transmit power, the nominal UE maximum transmit power, or the rated UE maximum transmit power.

[0417] As used in this disclosure, the terms "connected," "coupled," or any variation thereof, refer to any direct or indirect connection or coupling between two or more elements, and may include the presence of one or more intermediate elements between two elements that are "connected" or "coupled" to each other. The coupling or connection between elements may be physical, logical, or a combination thereof. For example, "connected" may be read as "access."

[0418] In this disclosure, when two elements are connected, they may be considered to be "connected" or "coupled" to one another using one or more wires, cables, printed electrical connections, etc., as well as using electromagnetic energy having wavelengths in the radio frequency range, microwave range, light (both visible and invisible) range, etc., as some non-limiting and non-exhaustive examples.

[0419] In the present disclosure, the term "A and B are different" may mean "A and B are different from each other." The term may also mean "A and B are each different from C." Terms such as "separate" and "coupled" may also be interpreted in the same way as "different."

[0420] When the terms "include," "including," and variations thereof are used in this disclosure, these terms are intended to be inclusive, similar to the term "comprising." Furthermore, when the term "or" is used in this disclosure, it is not intended to be an exclusive or.

[0421] In this disclosure, where articles are added by translation, such as a, an, and the in English, the disclosure may include that the nouns following these articles are in the plural form.

[0422] In the present disclosure, terms such as "less than or equal to," "less than," "greater than," "more than," "equal to," etc. may be interchangeable. Furthermore, in the present disclosure, terms meaning "good," "bad," "big," "small," "high," "low," "fast," "slow," "wide," "narrow," etc. may be interchangeable, not limited to the positive, comparative, and superlative. Furthermore, in the present disclosure, terms meaning "good," "bad," "big," "small," "high," "low," "fast," "slow," "wide," "narrow," etc. may be interchangeable, not limited to the positive, comparative, and superlative, as expressions with "i-th" (i is an arbitrary integer) attached (for example, "highest" may be interchangeable with "i-th highest").

[0423] In this disclosure, the terms "of," "for," "regarding," "related to," "associated with," etc. may be read interchangeably.

[0424] Although the invention according to the present disclosure has been described in detail above, it is clear to those skilled in the art that the invention according to the present disclosure is not limited to the embodiments described in the present disclosure. The invention according to the present disclosure can be implemented in modified and altered forms without departing from the spirit and scope of the invention as defined by the description of the claims. Therefore, the description of the present disclosure is intended to be illustrative and explanatory and does not impose any limiting meaning on the invention according to the present disclosure.

Claims

1. A receiving unit for receiving a reference signal; A terminal having a control unit that determines whether to perform multiple repetitive transmission of a physical random access channel (PRACH) or to transmit a PRACH without the multiple repetitive transmission based on a received power of the reference signal.

2. The terminal according to claim 1 , wherein the control unit controls the number of repetitions of the multiple repeat transmission based on a value of a counter related to a failure of a random access procedure including the multiple repeat transmission.

3. The terminal described in claim 1, wherein the multiple repeated transmissions of the PRACH use the same spatial domain filter for multiple PRACH occasions.

4. The terminal of claim 3, wherein the multiple PRACH occasions are associated with the same synchronization signal block (SSB) index.

5. A step of receiving a reference signal; determining whether to perform multiple repetitive transmission of a physical random access channel (PRACH) or to transmit a PRACH without the multiple repetitive transmission based on the received power of the reference signal.

6. A transmitter for transmitting a reference signal; A base station having a control unit that sets a threshold for a terminal to decide whether to perform multiple repetitive transmission of a physical random access channel (PRACH) or to transmit a PRACH without the multiple repetitive transmission based on the received power of the reference signal.

7. A system including a terminal and a base station, The terminal includes: A receiver for receiving a reference signal; A control unit that determines whether to perform multiple repetition transmission of a physical random access channel (PRACH) or to transmit a PRACH without the multiple repetition transmission based on a received power (RSRP) of the reference signal, The base station, A system comprising a transmitter for transmitting the reference signal.