Terminals, wireless communication methods, base stations and systems

Abstract

A terminal according to one aspect of the present disclosure comprises: a reception unit that receives at least one first reference signal; and a control unit that, on the basis of the reception power of the at least one first reference signal, determines whether to perform a single random access channel transmission or a plurality of random channel transmissions for a random access channel transmission trial, and / or determines the number of random access channel transmissions for the trial, and if the trial fails, selects a third reference signal for determining a retry resource, on the basis of the determination and the reception power of at least one second reference signal.

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 includes a receiving unit that receives one or more first reference signals, and a control unit that determines, based on the received power of the one or more first reference signals, at least one of whether to perform a single random access channel transmission or multiple random channel transmissions in an attempt to transmit a random access channel and the number of random access channel transmissions in the attempt, and, if the attempt fails, selects a third reference signal for determining resources for a retry based on the received power of one or more second reference signals and the determination.

[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 occasion and beam association. FIG. 3 shows an example of an RAR window. FIG. 4 shows an example of an RO group. FIGS. 5A and 5B show an example of a set of RSRP thresholds for UE power classes. FIG. 6 shows an example of a relationship between RSRP ranges and parameter sets. FIG. 7 shows an example of Option 1 of embodiment C-1. FIG. 8 shows an example of embodiment C-3. FIG. 9 shows an example of multiple RACH attempts. FIG. 10 shows an example of Option 1 of embodiment 1-1. FIG. 11 shows an example of Option 2 of embodiment 1-1. FIG. 12 shows an example of K=2 and Option 1-1 of embodiment 2-1. FIG. 13 shows an example of K=2 and Option 1-2 of embodiment 2-1. FIG. 14 shows an example of K=2 and Option 1-3 of embodiment 2-1. FIG. 15 shows an example of K=2 and options 1-4 in embodiment 2-1. FIG. 16 shows an example of K=4 and options 1-1 and 1-3 in embodiment 2-1. FIG. 17 shows an example of K=4 and options 1-2 and 1-4 in embodiment 2-1. FIG. 18 shows an example of K>1 and options 1-5 in embodiment 3-1. FIG. 19 is a diagram showing an example of a schematic configuration of a wireless communication system according to an embodiment. FIG. 20 is a diagram showing an example of a configuration of a base station according to an embodiment. FIG. 21 is a diagram showing an example of a configuration of a user terminal according to an embodiment. FIG. 22 is a diagram showing an example of the hardware configuration of a base station and a user terminal according to an embodiment. FIG. 23 is a diagram showing 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] (PRACH Configuration) 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.

[0032] 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 to one PRACH occasion and the number R of CB preambles per SS / PBCH block per valid PRACH occasion via ssb-perRACH-OccasionAndCB-PreamblesPerSSB.

[0033] 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.

[0034] Starting from frame 0, the association period for mapping SS / PBCH blocks to PRACH occasions is N Tx SSBThe UE selects 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 SS / PBCH block indices are mapped to a PRACH occasion at least once within that association period, where N SS / PBCH block indices are selected from the values ​​of ssb-PositionsInBurst in SIB1 or in the common serving cell configuration. Tx SSB If after an integer number of mapping cycles from SS / PBCH block index to PRACH occasion within the association period, N Tx SSB If there is a set of PRACH occasions or PRACH preambles that are not mapped to an SS / PBCH block index, 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, then that PRACH occasion is not used for PRACH.

[0035] 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.

[0036] 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.

[0037] For a given preamble index, the ordering of PRACH occasions is as follows: First, in increasing order of frequency resource index for frequency multiplexed PRACH occasions; Second, in increasing order of time resource index for time multiplexed PRACH occasions within a PRACH slot; Third, in increasing order of PRACH slot index.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] FIG. 2A shows an example (mapping 1) of association of PRACH occasions (RACH occasions (ROs)) and beams (SSB / CSI-RS) based on the higher layer parameter ssb-perRACH-OccasionAndCB-PreamblesPerSSB. When 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 indices 0 to 15 are associated with two ROs, and preamble indices 0 to 15 are associated with SSB0. In this way, when N<1, one SSB is mapped to multiple ROs. This increases the RO capacity per beam.

[0042] Figure 2B shows another example (mapping 2) of association of ROs and beams based on the upper layer parameters ssb-perRACH-OccasionAndCB-PreamblesPerSSB. When 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-multiplexed in one time instance, and four SSBs are mapped to one RO. One RO is associated with SSBs #0 to #3. Preamble indexes #0 to #15 are associated with SSB #0, preamble indexes #16 to #31 are associated with SSB #1, preamble indexes #32 to #47 are associated with SSB #2, and preamble indexes #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 by the received PRACH.

[0043] 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 it is FR1 or FR2 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.

[0044] 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.

[0045] (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 1s, 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).

[0046] For a PRACH transmission triggered by a PDCCH order, the PRACH mask index field indicates the PRACH occasion of the PRACH transmission that is 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.

[0047] Random access procedure in MAC entity: MAC protocol specification: Random Access procedure initialization 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 be only 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.

[0048] 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 4-step RA type contention-free random access resource is explicitly provided by rach-ConfigDedicated for the BWP selected for the random access procedure.

[0049] 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 has been selected as above, determine the next available PRACH occasion from those 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.)

[0050] (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 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.

[0051] (SSB / CSI-RS selection: MAC protocol specification: Random Access Resource selection) If RA_TYPE is set to 4-step RA, the MAC entity performs the following actions: When an RA procedure is initiated for SpCell beam failure recovery, and the beam failure recovery timer (beamFailureRecoveryTimer) is running or not set, and CFRA resources for the beam failure recovery request associated with at least one SSB / CSI-RS are explicitly provided by RRC, and at least one of the following is available: one or more SSBs with SS-RSRP exceeding the SS-RSRP threshold (rsrp-ThresholdSSB) among the multiple SSBs in the candidate beam RS list (candidateBeamRSList), and one or more CSI-RSs with CSI-RSRP exceeding the CSI-RSRP threshold (rsrp-ThresholdCSI-RS) among the multiple CSI-RSs in the candidate beam RS list (candidateBeamRSList), the MAC entity performs the following operations. The MAC entity selects one SSB with an SS-RSRP that exceeds rsrp-ThresholdSSB from among the SSBs in the candidateBeamRSList, or one CSI-RS with a CSI-RSRP that exceeds rsrp-ThresholdCSI-RS from among the CSI-RSs in the candidateBeamRSList. If a CSI-RS is selected and there is an RA-PreambleIndex associated with the selected CSI-RS, the MAC entity sets the preamble index (PREAMBLE_INDEX) to the ra-PreambleIndex corresponding to the SSB in the candidateBeamRSList that is quasi-colocated with the selected CSI-RS.-- Otherwise, set PREAMBLE_INDEX to the ra-PreambleIndex corresponding to the SSB or CSI-RS selected from the set of RA preambles for beam failure recovery request.

[0052] Otherwise, if ra-PreambleIndex is explicitly provided by the PDCCH and is not 0b000000, the MAC entity shall set PREAMBLE_INDEX to the signaled ra-PreambleIndex and select the SSB signaled by the PDCCH.

[0053] Otherwise, if CFRA resources associated with multiple SSBs are explicitly provided in the dedicated RACH configuration (rach-ConfigDedicated) and at least one SSB with SS-RSRP above rsrp-ThresholdSSB is available, the MAC entity shall select one SSB from the associated SSBs with SS-RSRP above rsrp-ThresholdSSB and set PREAMBLE_INDEX to the ra-PreambleIndex corresponding to the selected SSB.

[0054] Otherwise, if CFRA resources associated with multiple CSI-RSs are explicitly provided in the dedicated RACH configuration (rach-ConfigDedicated) and at least one CSI-RS with a CSI-RS SRP above rsrp-ThresholdCSI-RS is available among the multiple CSI-RSs, the MAC entity shall select one CSI-RS with a CSI-RS SRP above rsrp-ThresholdCSI-RS among its associated multiple CSI-RSs and set PREAMBLE_INDEX to the ra-PreambleIndex corresponding to the selected CSI-RS.

[0055] - Otherwise, if an RA procedure is initiated for an SI request and RA resources for the SI request have been explicitly provided by RRC, the MAC entity shall: -- If at least one SSB with SS-RSRP above rsrp-ThresholdSSB is available, the MAC entity shall select one SSB with SS-RSRP above rsrp-ThresholdSSB. -- Otherwise, the MAC entity shall select any SSB. -- The MAC entity shall select an RA preamble corresponding to the selected SSB from the RA preambles examined according to the RA-PreambleStartIndex (ra-PreambleStartIndex) and set PREAMBLE_INDEX to the selected RA preamble.

[0056] - Otherwise (CBRA preamble selection), the MAC entity shall: -- If at least one SSB with SS-RSRP above rsrp-ThresholdSSB is available, the MAC entity shall select one SSB with SS-RSRP above rsrp-ThresholdSSB. -- Otherwise, the MAC entity shall select any SSB.

[0057] (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] When the UE is not provided with tdd-UL-DL-ConfigurationCommon, 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. When channelAccessMode=semistatic is provided, it does not overlap with the set of consecutive symbols before the start of the next channel occupancy 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.

[0058] (PRACH Transmission Power Control: Physical Layer Procedures for Control / Uplink Power Control / Physical Random Access Channel) The actual PRACH transmission power is determined based on the target preamble reception power, the path loss of the RS, and the maximum output power limit.

[0059] The UE determines the (actual) transmit power P of the PRACH on the active UL BWP b of carrier f of serving cell c based on the DL RS for serving cell c in transmission occasion i. PRACH,b,f,c (i) is determined as follows: P PRACH,b,f,c (i) = min{P CMAX,f,c (i),P PRACH,target,f,c +PL b,f,c} [dBm]

[0060] P CMAX,f,c (i) is the maximum output power configured for the UE for carrier f of serving cell c in transmission occasion i. P PRACH,target,f,c is the PRACH target received power PREAMBLE_RECEIVED_TARGET_POWER provided by higher layers for the active UL BWP b of carrier f of serving cell c. b,f,cis the path loss for the active UL BWP b of carrier f based on the DL RS associated with the PRACH transmission on the active DL BWP of serving cell c, and is calculated by the UE as (reference signal power (ss-PBCH-BlockPower) [dBm] - upper layer filtered RSRP [dBm]) [dB]. If the active DL BWP is the initial DL BWP and is for multiplexing pattern 2 or 3 of the SS / PBCH block and CORESET, the UE calculates the path loss for the active UL BWP b of carrier f based on the DL RS associated with the PRACH transmission on the active DL BWP of serving cell c, and is calculated by the UE as (reference signal power (ss-PBCH-BlockPower) [dBm] - upper layer filtered RSRP [dBm]) [dB]. b,f,c Determine.

[0061] The DL RS used in the path loss calculation may be referred to as a pathloss (PL)-RS, a pathloss reference RS, or the like.

[0062] In the existing RACH process, if a UE sends a PRACH and does not receive a network RAR or contention / conflict resolution Msg 4 within a specific time window, and the random access process is not completed, the UE will retransmit the PRACH after a random backoff time.

[0063] (Target preamble reception power: MAC protocol specification / MAC procedures / Random Access procedure) The UE calculates the transmission power based on the target preamble reception power set by the network and the value of the preamble power ramping counter (power lifting / ramping mechanism).

[0064] preambleReceivedTargetPower is the initial random access preamble power for 4-step RA type. DELTA_PREAMBLE relates to the preamble format. PREAMBLE_POWER_RAMPING_COUNTER is the number of times the power is ramped up. PREAMBLE_POWER_RAMPING_STEP is the step size of the power lifting / ramping.

[0065] For each RA preamble, the MAC entity performs the following actions: - if the selected SSB or CSI-RS has not changed since the selection in the side's RA preamble transmission, - increment PREAMBLE_POWER_RAMPING_COUNTER by 1, - select a value for DELTA_PREAMBLE, - set PREAMBLE_RECEIVED_TARGET_POWER to preambleReceivedTargetPower + DELTA_PREAMBLE + (PREAMBLE_POWER_RAMPING_COUNTER-1)*PREAMBLE_POWER_RAMPING_STEP + POWER_OFFSET_2STEP_RA.

[0066] If a valid downlink assignment is received on the PDCCH for the RA-RNTI, the received TB is successfully decoded, the reception of the RAR is considered successful, and the RAR does not contain a MAC subPDU with only a RAPID, the MAC entity applies the following actions to the serving cell from which the RAR preamble was transmitted: - process the received timing advance command, - indicate to lower layers the preambleReceivedTargetPower and the amount of power ramping applied to the last RA preamble transmission (i.e., PREAMBLE_POWER_RAMPING_COUNTER - 1) × PREAMBLE_POWER_RAMPING_STEP), - ignore the received UL grant if an RA procedure for the SCell is taking place on an uplink carrier for which pusch-Config is not configured.

[0067] As mentioned above, if the selected SSB / CSI-RS has not changed since the last SSB / CSI-RS selection, the UE increments the power ramping counter (PREAMBLE_POWER_RAMPING_COUNTER).

[0068] PREAMBLE_POWER_RAMPING_STEP is set by powerRampingStep {0dB, 2dB, 4dB, 6dB} in the RRC IE RACH-ConfigGeneric.

[0069] (Maximum number of preamble transmissions: MAC protocol specification / MAC procedures / Random Access procedure) preambleTransMax is the maximum number of random access preamble transmissions.

[0070] If a listen before talk (LBT) failure is received from lower layers for a random access preamble transmission and lbt-FailureRecoveryConfig is not configured, the MAC entity shall perform the following actions: - The MAC entity shall increment the preamble transmission counter (PREAMBLE_TRANSMISSION_COUNTER) by 1. - If PREAMBLE_TRANSMISSION_COUNTER = preambleTransMax + 1: -- If the random access preamble is being transmitted on the SpCell, the MAC entity shall indicate an RA problem to upper layers, and if the RA procedure is triggered due to an SI request, the MAC entity shall consider the RA procedure as having failed to complete. -- If the random access preamble is being transmitted on the SCell, the MAC entity shall consider the RA procedure as having failed to complete. - If the RA procedure is not completed, the MAC entity shall perform an RA resource selection procedure.

[0071] If the ra-ResponseWindow configured in BeamFailureRecoveryConfig expires and if no PDCCH transmission on the search space indicated by recoverySearchSpaceId for 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 if no RAR is received containing a random access preamble identifier matching the transmitted PREAMBLE_INDEX, the MAC entity shall: - consider the RAR reception as unsuccessful, - increment PREAMBLE_TRANSMISSION_COUNTER by 1, - if PREAMBLE_TRANSMISSION_COUNTER = preambleTransMax + 1: If the random access preamble is transmitted on the SpCell, the MAC entity indicates an RA problem to upper layers, and if the RA procedure is triggered due to an SI request, the MAC entity considers the RA procedure to have failed to complete. -- If the random access preamble is transmitted on the SCell, the MAC entity considers the RA procedure to have failed to complete.

[0072] If contention resolution is deemed unsuccessful, the MAC entity flushes (clears) the HARQ buffers used for transmission of MAC PDUs in the Msg3 buffer, increments the PREAMBLE_TRANSMISSION_COUNTER by 1, indicates the RA problem to upper layers, and if the RA procedure was triggered due to an SI request, the MAC entity considers the RA procedure to have failed to complete.

[0073] (RAR 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).

[0074] In the present disclosure, SpCell, primary cell (PCell), and primary secondary cell (PSCell) may be read as interchangeable.

[0075] Once the RA preamble is transmitted, the MAC entity performs the following actions 1 to 3, regardless of whether a measurement gap may occur.

[0076] [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 the C-RNTI.

[0077] [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.

[0078] [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.

[0079] 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.

[0080] 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.

[0081] 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.

[0082] [Action 4] The MAC entity starts the Msg. B response window (msgB-ResponseWindow) in the PDCCH monitoring window defined in the specification.

[0083] The msgB-ResponseWindow may start at the first symbol of the earliest CORESET for which the UE is configured to receive a 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.

[0084] [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.

[0085] [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.

[0086] (RA-RNTI: MAC protocol specification / Random Access Preamble transmission) 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

[0087] where s_id is the index of the first OFDM symbol of the PRACH occasion (0<=s_id<14 (number of symbols in a slot)). t_id is the index of the first slot of the PRACH occasion in the system frame (0<=t_id<80 (number of slots in a system frame when SCS is 120 kHz)). 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 (maximum number of FDMed PRACH occasions)). 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.

[0088] 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

[0089] 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.

[0090] The total number of RA-RNTI values ​​(total number of PRACH occasions in a system frame) is 14 x 80 x 8 x 2. The MSGB-RNTI formula is the RA-RNTI formula plus the total number of RA-RNTI values. This formula avoids collisions between MSGB-RNTI and RA-RNTI.

[0091] (RAR Monitoring) 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 provided by the ra-responseWindow as the number of slots.

[0092] If a UE detects DCI format 1_0 with a CRC scrambled by the corresponding RA-RNTI and with the least significant bits (LSBs) of the system frame number (SFN) field in that DCI format being 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.

[0093] If a UE attempts to detect DCI format 1_0 with a 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 a 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.

[0094] 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.

[0095] In single-cell operation or operation with carrier aggregation within the same frequency band, if the qcl-Type set in the 'type D' properties of a DMRS for monitoring a PDCCH in a Type 1-PDCCH CSS set is not set to the same as the qcl-Type set in the 'type D' properties of a DMRS for monitoring a PDCCH in a Type 0 / 0A / 0B / 2 / 3-PDCCH CSS set or in a USS set, and that PDCCH or associated PDSCH overlaps by at least one symbol with a PDCCH or associated PDSCH that the UE monitors in the Type 1-PDCCH CSS set, then the UE shall not assume to monitor a PDCCH in a Type 0 / 0A / 0B / 2 / 3-PDCCH CSS set or in a USS set.

[0096] If a UE is provided with one or more search space sets by PDCCH-Config, corresponding to one or more of searchSpaceZero, searchSpaceSIB1, searchSpaceOtherSystemInformation, pagingSearchSpace, peiSearchSpace, ra-SearchSpace, and a CSS set, and is provided with SI-RNTI, P-RNTI, PEI-RNTI, RA-RNTI, MsgB-RNTI, SFI-RNTI, INT-RNTI, TPC-PUSCH-RNTI, TPC-PUCCH-RNTI, or TPC-SRS-RNTI, for an RNTI from any of these RNTIs, the UE shall not process information from more than one DCI format with CRC scrambled using that RNTI per slot.

[0097] (Msg3 PUSCH) The UE transmits a transport block on the PUSCH scheduled by the RAR UL grant in the corresponding RAR message. The UE transmits a transport block on the PUSCH in slot n+k2+Δ+2. μ ・K cell,offset The PUSCH is transmitted within K cell,offsetThe offset is provided by CellSpecific_Koffset, and if not provided, K cell,offset =0.

[0098] k2 is a slot offset determined based on the row index m+1 of the allocation table provided by the PUSCH time resource allocation field value m of the RAR UL grant and the PUSCH subcarrier spacing μPUSCH. Δ is an additional subcarrier spacing-specific slot delay time value for the first transmission of the PUSCH scheduled by the RAR, which is specific to the PUSCH subcarrier spacing μPUSCH and is applied in addition to K2.

[0099] If a UE requests repetition for PUSCH transmission, the UE PUSCH repeat PUSCH is transmitted over N slots, where PUSCH repeat is indicated by the 2 MSBs of the MCS field in the RAR UL grant or DCI format 0_0, from the set of four values ​​provided by numberOfMsg3Repetitions, or from {1,2,3,4} if numberOfMsg3Repetitions is not provided.

[0100] The UE decides whether to apply Msg3 repetition based on the RSRP. If Msg repetition is configured and the RSRP of the DL pathloss reference is smaller than rsrp-ThresholdMsg3 (threshold), the MAC entity assumes that Msg3 repetition is applicable to the current random access (RA) procedure.

[0101] The UE can request Msg3 PUSCH repetition via a separate PRACH resource. The MAC entity selects RA resources if there are one or more sets of available RA resources, and one of the one or more sets is used to indicate all functions that trigger this RA procedure, or if there are one or more sets of available RA resources configured with indications for a subset of all functions that trigger this RA procedure. If the Msg3 repetition indication is configured for a set of RA resources, and Msg3 repetition is not available, the MAC entity considers that set of RA resources as not available for the RACH procedure.

[0102] The RA resources may be partitioned for each function, which may include at least one of Msg3 repetition, reduced capacity (RedCap), small data transmission (SDT), and RAN slicing.

[0103] The following are signaled in SIB1 sent by the base station: Priority of each feature (priority, featurePriorities-r17). This priority is used by the UE to decide which FeatureCombinationPreamble to use if a feature is mapped to more than one. Additional RO configuration. The configuration includes available features (which may be associated with multiple features), RA resources (e.g., preamble index), and mask index to distinguish ROs.

[0104] The UE decides which RO to use depending on its capabilities.

[0105] SIB1 includes ServingCellConfigCommonSIB, which includes UplinkConfigCommonSIB, which includes BWP-UplinkCommon (UL BWP common configuration).

[0106] BWP-UplinkCommon may include a RACH common configuration (RACH-ConfigCommon or MsgA-ConfigCommon) and an additionalRACH-ConfigList-r17 (an additional RACH configuration list). The additionalRACH-ConfigList-r17 may include a rsrp-ThresholdMsg3-r17 (a threshold value).

[0107] The RACH common configuration may include FeatureCombinationPreambles. FeatureCombinationPreambles associates one set of preambles (partition) with one feature combination. FeatureCombinationPreambles may include FeatureCombination (feature combination configuration), startPreambleForThisPartition (index of the first preamble), numberOfPreamblesPerSSB-ForThisPartition (number of preambles), and ssb-SharedRO-MaskIndex-r17 (PRACH mask index). FeatureCombination includes at least one of redCap (RedCap), smallData (SDT), sliceGroup (RAN slicing), and msg3-Repetition (Msg3 repetition). A partition is given by the index of the first preamble and the number of preambles.

[0108] The available ROs are explicitly configured by the PRACH mask index. At least one of the PRACH occasion indexes 1 to 8 can be configured using the relationship between the PRACH mask index and the allowed PRACH occasions (ROs) of the SSB (MAC protocol specification / PRACH mask index value table).

[0109] The number of Msg3 repetitions is indicated by the 2 most significant bits (MSBs) of the modulation and coding scheme (MCS) field in the RAR UL grant.

[0110] In the case of PUSCH repetition type A, when transmitting a PUSCH scheduled by an RAR UL grant, the 2 MSBs of the MCS information field of the RAR UL grant provide a code point for determining the repetition number K according to the relationship (table) between the value (code point) of the 2 MSBs of the MCS information field and the repetition number K, depending on whether the upper layer parameter numberOfMsg3Repetitions is set or not. The number of slots N used for determining the transport block size (TBS) is equal to 1.

[0111] In PUSCH repetition type B, when transmitting a PUSCH scheduled by DCI format 0_0 with CRC scrambled by TC-RNTI, the 2 MSBs of the MCS information field of that DCI format provide a code point for determining the repetition number K according to the relationship (table) between the value (code point) of the 2 MSBs of the MCS information field and the repetition number K, based on whether the upper layer parameter numberOfMsg3Repetitions is set or not. The number of slots N used for TBS determination is equal to 1.

[0112] (Contention Resolution) When Msg 3 is transmitted, the MAC entity follows actions 1 to 4 below. [Action 1] If Msg 3 is transmitted over a non-terrestrial network, the MAC entity starts the ra-ContentionResolutionTimer and restarts it at each HARQ retransmission in the first symbol after the end of Msg 3 plus the UE estimate of the UE-gNB RTT. [Action 2] Otherwise, if the Msg 3 transmission (initial transmission or HARQ retransmission) is scheduled with a Type A PUSCH repetition, the MAC entity starts or restarts the ra-ContentionResolutionTimer in the first symbol after the end of all repetitions of the Msg 3 transmission. [Action 3] Otherwise, the MAC entity starts or restarts the ra-ContentionResolutionTimer in the first symbol after the end of the Msg 3 transmission. [Operation 4] The MAC entity monitors the PDCCH while the ra-ContentionResolutionTimer is running, regardless of the possibility of a measurement gap occurring.

[0113] Step 4 (Msg4) in the RA procedure for Rel. 16 NR follows the following step 4 operations:

[0114] Step 4 Operation: If the UE is not provided with a C-RNTI, in response to a PUSCH transmission scheduled by the RAR UL grant, the UE schedules a PDSCH containing the UE contention resolution identity and attempts to detect DCI format 1_0 with a CRC scrambled by the corresponding TCI-RNTI. In response to receiving a PDSCH containing the UE contention resolution identity, the UE transmits HARQ-ACK information in the PUCCH. The PUCCH transmission is within the same active UL BWP as the PUSCH transmission. The minimum time between the last symbol of the PDSCH reception and the first symbol of the corresponding PUCCH transmission containing HARQ-ACK information is equal to N_T,1 [msec]. N_T,1 is the duration of N_T,1 symbols, which corresponds to the PDSCH processing time of UE processing capability 1 when additional PDSCH DM-RS is configured. For μ=0, the UE assumes N_T,1=14.

[0115] When detecting a DCI format in response to a PUSH transmission scheduled by an RAR UL grant or in response to a corresponding PUSH retransmission scheduled by DCI format 0_0 with CRC scrambled by the TC-RNTI provided in the corresponding RAR message, the UE may assume that the PDCCH carrying that DCI format has the same DM-RS antenna port quasi co-location (QCL) properties as the DM-RS antenna port QCL properties for the SS / PBCH block used by the UE for PRACH association, regardless of whether the UE has been provided with the TCI state for the CORESET in which the UE received the PDCCH with that DCI format.

[0116] (Type 2 RA Procedure) In a MsgA transmission within a Type 2 RA procedure (two-step RA procedure), the UE transmits the following pairs: - one preamble with one preamble index within a MsgA RACH Occasion (RO), - one PUSCH with one PUSCH resource unit (PRU) within a MsgA PUSCH Occasion (PO) per MsgA PUSCH configuration.

[0117] The MsgA PRACH has the structure of MsgA preamble index (code domain resource) within MsgA RACH occasion (time domain resource / frequency domain resource).

[0118] The MsgA PUSCH has a structure of an MsgA PUSCH resource unit (code domain resource / spatial domain resource) within an MsgA PUSCH occasion (time domain resource / frequency domain resource) within an MsgA PUSCH configuration (RRC configuration).

[0119] Within a MsgA PUSCH occasion (time domain resource / frequency domain resource), multiple PRUs can be multiplexed using DMRS ports / DMRS sequences. Only in CP-OFDM, more than one DMRS sequence can be configured.

[0120] (MsgA PUSCH Occasion in Type 2 RA Procedure) A MsgA PUSCH Occasion (PO) that overlaps with a valid RO for a Type 1 / 2 RA procedure is an invalid PO.

[0121] A PUSCH occasion is valid if it does not overlap in time and frequency with any valid PRACH occasion associated with a Type 1 RA procedure or a Type 2 RA procedure. For unpaired spectrum (TDD) and SS / PBCH blocks with indices provided by ssb-PositionsInBurst in SIB1 or by ServingCellConfigCommon, the UE follows several actions:

[0122] If the UE is not provisioned with tdd-UL-DL-ConfigurationCommon, a PUSCH occasion is valid if it satisfies the following conditions: -- the PUSCH occasion precedes an SS / PBCH block in that PUSCH slot, and -- the PUSCH occasion is at least N symbols from the last SS / PBCH block. gap symbols after the PUSCH occasion, and if channelAccessMode="semiStatic" is provided, the PUSCH occasion does not overlap with the set of consecutive symbols before the start of the next channel occupation period during which the UE does not transmit, where N gap is provided in a table of specifications.

[0123] - If the UE is provided with tdd-UL-DL-ConfigurationCommon and the PUSCH occasion satisfies the following conditions, then the PUSCH occasion is valid: -- the PUSCH occasion is within an UL symbol, or -- the PUSCH occasion precedes an SS / PBCH block in the PUSCH slot, and -- the PUSCH occasion is at least N DL symbols from the last DL symbol. gap symbols after the last SS / PBCH block symbol and at least N gap symbols after the PUSCH occasion, and if channelAccessMode="semiStatic" is provided, the PUSCH occasion does not overlap with the set of consecutive symbols before the start of the next channel occupation period during which the UE does not transmit, where N gap is provided in a table of specifications.

[0124] PRACH Collision: Physical Layer Procedures for Control / Slot Configuration In operation on a single carrier in unpaired spectrum (TDD), if a UE is configured by higher layers to transmit SRS or PUCCH or PUSCH or PRACH in a set of symbols of one slot, and the UE detects a DCI format that indicates to the UE to receive CSI-RS or PDSCH in a subset of symbols from the set of symbols, the UE shall follow the following actions: - If the UE does not indicate partial cancellation capability, the UE shall follow the following actions: -- If the first symbol in the set of symbols is T from the last symbol of the CORESET in which the UE detects the DCI format proc,2 , the UE does not expect to cancel the PUCCH or PUSCH or PRACH transmission in that symbol set. Otherwise, the UE cancels the actual repetition of PUCCH or PUSCH or PUSCH or PRACH transmission in that symbol set. - If the UE indicates partial cancellation capability, the UE shall follow the following actions: - The UE shall check that the first symbol in the symbol set is within T from the last symbol of the CORESET in which the UE detects the DCI format. proc,2 The UE does not expect to cancel PUCCH or PUSCH or PRACH transmissions in symbols from that symbol set that occur within the set of symbols. The UE cancels actual repetitions of PUCCH or PUSCH or PRACH transmissions in the remaining symbols from that symbol set.

[0125] That is, if a PRACH triggered / configured by higher layers overlaps with a symbol scheduled for DL ​​reception by DCI, the UE will cancel that PRACH.

[0126] When operating on a single carrier in unpaired spectrum (TDD), if a transmission would overlap with any symbol from a set of symbols in a slot in which the UE is instructed to receive a particular SS / PBCH block, the UE shall not transmit PUSCH, PUCCH, PRACH in that slot, and the UE shall not transmit SRS in that set of symbols in that slot. The specific SS / PBCH block is the SS / PBCH block according to ssb-PositionsInBurst in SIB1 (SystemInformationBlockType1), or according to ssb-PositionsInBurst in ServingCellConfigCommon, or according to ssb-PositionsInBurst in SSB-MTCAdditionalPCI associated with a physical cell ID with active TCI state for PDCCH or PDSCH if the UE is not provisioned with dl-OrJoint-TCIStateList, or for the set of symbols in a slot corresponding to the SS / PBCH block configured for L1 beam measurement / reporting. If tdd-UL-DL-ConfigurationCommon or tdd-UL-DL-ConfigurationDedicated is provisioned to the UE, it is not expected that the set of symbols in that slot is indicated as uplink by the tdd-UL-DL-ConfigurationCommon or tdd-UL-DL-ConfigurationDedicated.

[0127] If a UE is configured with multiple serving cells and is provided with directionalCollisionHandling-r16 = 'enabled' for a set of serving cells among the multiple serving cells, and indicates support for the half-DuplexTDD-CA-SameSCS-r16 capability, and is not configured to monitor the PDCCH for detection of DCI format 2_0 on any of the multiple serving cells, the UE shall follow the following behavior: - If the transmission would overlap with any symbol from the set of symbols of a slot in which the UE is instructed to receive a specific SS / PBCH block in the first cell among the multiple serving cells, the UE shall not transmit PUSCH, PUCCH, PRACH in that slot, and the UE shall not transmit SRS in that set of symbols of that slot in the specific cell. The specific SS / PBCH block is the SS / PBCH block for the set of symbols of slots corresponding to the SS / PBCH block configured for L1 beam measurement / reporting according to ssb-PositionsInBurst in SIB1 (SystemInformationBlockType1), or according to ssb-PositionsInBurst in ServingCellConfigCommon, or according to ssb-PositionsInBurst in SSB-MTCAdditionalPCI associated with the physical cell ID with active TCI state for PDCCH or PDSCH if the UE is not provided with dl-OrJoint-TCIStateList, or the specific cell is one of the multiple serving cells if it does not have the simultaneous transmission / reception capability indicated by simultaneousRxTxInterBandCA, or one of the cells corresponding to the same band as the first cell, regardless of the capability indicated by simultaneousRxTxInterBandCA.

[0128] That is, if a PRACH triggered / configured by higher layers overlaps with an SSB symbol, the UE will not transmit that PRACH.

[0129] (PRACH Collision: Physical layer procedures for control / UE procedure for determining slot format) In the set of symbols of a slot that is indicated to the UE as flexible by tdd-UL-DL-ConfigurationCommon and tdd-UL-DL-ConfigurationDedicated when tdd-UL-DL-ConfigurationCommon and tdd-UL-DL-ConfigurationDedicated are provided, or when tdd-UL-DL-ConfigurationCommon and tdd-UL-DL-ConfigurationDedicated are not provided, or when the UE detects DCI format 2_0 that provides a format for that slot using a slot format value other than 255, the UE shall follow the following actions: If the SFI index field value in DCI format 2_0 indicates that the set of symbols in that slot is flexible, and the UE does not receive a DCI format that instructs the UE to receive PDSCH or CSI-RS, or does not receive a DCI format, RAR UL grant, fallback RAR UL grant, or success RAR that instructs the UE to transmit PUSCH, PUCCH, PRACH, or SRS in that set of symbols in that slot, the UE neither transmits nor receives in that set of symbols in that slot.

[0130] That is, if a PRACH without a PDCCH order overlaps with a symbol indicated as flexible by the SFI, the UE will not transmit that PRACH.

[0131] If a UE is configured by higher layers to transmit SRS or PUCCH or PUSCH or PRACH within a set of symbols of a slot, and the UE detects DCI format 2_0 with a slot format value other than 255 that indicates a slot format with a subset of symbols from the set of symbols as downlink or flexible, or receives a DCI format that indicates to the UE reception of CSI-RS or PDSCH within a subset of symbols from the set of symbols, the UE shall follow the following actions: - If the UE does not indicate partial cancellation capability, the UE shall follow the following actions: - If the first symbol in the set of symbols is within T from the last symbol of the CORESET in which the UE detects the DCI format proc,2 , the UE does not expect to cancel the PUCCH or PUSCH or PRACH transmission in that symbol set. Otherwise, the UE cancels the actual repetition of PUCCH or PUSCH or PUSCH or PRACH transmission in that symbol set. - If the UE indicates partial cancellation capability, the UE shall follow the following actions: - The UE shall check that the first symbol in the symbol set is within T from the last symbol of the CORESET in which the UE detects the DCI format. proc,2 The UE does not expect to cancel PUCCH or PUSCH or PRACH transmissions in symbols from that symbol set that occur within the set of symbols. The UE cancels actual repetitions of PUCCH or PUSCH or PRACH transmissions in the remaining symbols from that symbol set.

[0132] That is, if a PRACH configured by a higher layer overlaps with a symbol indicated as DL or flexible by the SFI, the UE cancels that PRACH.

[0133] In the set of symbols for a slot that is indicated to the UE as flexible by the tdd-UL-DL-ConfigurationCommon and tdd-UL-DL-ConfigurationDedicated if tdd-UL-DL-ConfigurationCommon and tdd-UL-DL-ConfigurationDedicated are provided, or if tdd-UL-DL-ConfigurationCommon and tdd-UL-DL-ConfigurationDedicated are not provided and the UE has not detected DCI format 2_0 that provides the slot format for that slot, the UE shall follow the following actions: - If the UE is configured by higher layers to transmit SRS or PUCCH or PUSCH or PRACH and the UE is not provided with enableConfiguredUL, the UE shall follow the following actions: -- If the UE does not indicate capability for partial cancellation, the UE shall follow the following actions: -- If the UE does not indicate capability for partial cancellation, the UE shall follow the following actions: If the first symbol of the PUCCH, PUSCH, or actual repetition of the PUSCH, or PRACH, is within T seconds from the last symbol of the CORESET that the UE is configured to monitor for the PDCCH for DCI format 2_0. proc,2 , the UE does not expect to cancel the PUCCH, or PUSCH, or actual repetition of PUSCH, or PRACH transmission in that slot. Otherwise, the UE cancels the PUCCH, or PUSCH, or actual repetition of PUSCH, or PRACH transmission in that slot. --- If the UE indicates partial cancellation capability, the UE shall follow the following actions: --- The UE shall monitor the PDCCH for DCI format 2_0 from the last symbol of the CORESET in which the UE is configured to monitor the PDCCH for DCI format 2_0. proc,2If a UE does not expect to cancel PUCCH or PUSCH or PRACH transmissions in symbols from that symbol set that occur within a slot, the UE cancels PUCCH or PUSCH or PRACH transmissions in that slot. The UE cancels PUCCH or PUSCH or PRACH transmissions in the remaining symbols from that symbol set.

[0134] That is, if a PRACH triggered / configured by higher layers overlaps with a semi-statically configured flexible symbol and the UE does not detect DCI format 2_0, the UE will cancel the PRACH.

[0135] (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.

[0136] In order to reduce the number of beams (synchronization signals / reference signals) and reduce overhead, using thick (wide) beams results in narrower coverage.

[0137] 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.

[0138] 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.

[0139] PRACH coverage extensions are being considered, such as multiple PRACH transmissions using the same beam (multiple repetitions of PRACH) in a four-step RACH procedure, and multiple PRACH transmissions using different beams in a four-step RACH procedure. This PRACH extension may target frequency range (FR) 2 or may apply to FR 1. This PRACH extension may apply to short PRACH formats or other formats.

[0140] For multiple PRACH transmissions with the same beam, one RAR window may be used for each PRACH transmission, and the RAR window may follow existing designs. For multiple PRACH transmissions with the same beam, only one RAR window may be used for all of the multiple PRACH transmissions.

[0141] The UE may use different transmit (Tx) beams for transmitting multiple PRACHs across multiple ROs associated with the same SSB / CSI-RS.

[0142] (PRACH Resources for Multiple PRACH Transmissions) It is being considered that multiple PRACH transmissions (multi-PRACH transmissions) are transmitted on ROs (separate ROs, ROs separated for multiple PRACH transmissions and single PRACH transmissions) that are separate from single PRACH transmissions (single PRACH transmissions), and that multiple PRACH transmissions are transmitted on ROs (shared ROs) that are shared with single PRACH transmissions using preambles (separate preambles) that are separate from single PRACH transmissions.

[0143] To distinguish multiple PRACH transmissions using the same Tx beam from a single PRACH transmission, it is considered to support multiple PRACH transmissions being transmitted on separate ROs.

[0144] In order to distinguish multiple PRACH transmissions using the same Tx beam from a single PRACH transmission, it is considered to support multiple PRACH transmissions being transmitted using separate preambles on a shared RO.

[0145] For multiple PRACH transmissions using the same Tx beam, an "RO group" is assumed for separate preambles on a shared RO and / or multiple PRACH transmissions on separate ROs. - All ROs in an RO group are associated with one or more of the same SSBs. - A shared RO / preamble means that the RO / preamble is shared with a single PRACH transmission. - A separate RO / preamble means that the RO / preamble is separate from a single PRACH transmission. - The effective RO is defined in existing specifications. The effective RO may follow the effective conditions of the PRACH occasions mentioned above.

[0146] (RAR Monitoring for Multiple PRACHs) In multiple PRACH transmissions using the same transmission beam, it is considered that only a single RAR window is supported in RAR monitoring for multiple PRACH transmissions within one RACH attempt.

[0147] The UE repeatedly transmits Msg1 on K 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 K ROs / RO resources may be referred to as an RO group. Figure 3 shows an example of the timing of multiple PRACH transmissions. In this example, the size of the RO group (the number of ROs in the RO group) is K. After one RO group, one RAR window begins.

[0148] In this disclosure, an RO group may be defined as consisting of K valid ROs that are TDM'd, with each time occasion having a single RO in the frequency domain. In other words, once an RO group is selected, the RO for each PRACH transmission is determined. In the example of Figure 4, when the repetition number K = 2, the RO group consists of two consecutive ROs that are TDM'd.

[0149] (Consideration) In multiple PRACH transmissions using the same Tx beam, it is considered that {2, 4, 8} be supported as the number of PRACH transmissions. In multiple PRACH transmissions using the same Tx beam, it is considered that one or more SSB-RSRP thresholds be used to determine the number of PRACH transmissions, at least for the first RACH attempt.

[0150] It is considered that switching (fallback) from single PRACH transmission to multiple PRACH transmission (PRACH repetition) is not supported, for example, it is considered that switching between single PRACH transmission and multiple PRACH transmission within one RACH procedure is not supported.

[0151] (Analysis 1) According to the existing PRACH transmit power calculation rules, for a specific PRACH format in the first RACH attempt (i.e., the case where the power ramping counter is equal to 0), the following is allowed: - The maximum UE output power limit is not taken into account (i.e., (P PRACH,target,f,c +PL b,f,c- When the maximum UE output power limit is taken into account (i.e., only min(P CMAX,f,c (i), P PRACH,target,f,c +PL b,f,c ) is considered), if the path loss is very large, i.e., the detected SINR is very low, then PRACH,target,f,c +PL b,f,c ), the PRACH transmit power is limited by the maximum UE output power limit, and the PRACH received power at the base station side may be lower than (preambleReceivedTargetPower + DELTA_PREAMBLE).

[0152] In view of this, it is preferable that the restriction on multiple PRACH transmissions may be triggered only if the transmission power reaches (exceeds) the maximum UE output power limit.

[0153] (Analysis 2) Multiple PRACH transmissions may result in an unfair situation. For example, if the RSRP of the SSB selected by UE #1 is higher than that of the SSB selected by UE #2 (e.g., there is a 2 dB gap between them), UE #1 is assumed to perform a single PRACH transmission and UE #2 is assumed to perform two PRACH transmissions. As a result, considering the base station's combining gain (e.g., a 3 dB combining gain for two PRACH transmissions), the target performance for UE #2's preamble is better than the target performance for UE #1's preamble. This is different from the motivation for supporting multiple PRACH transmissions in Rel. 18.

[0154] The motivation for multiple PRACH transmissions is to compensate for poor performance for some UEs in order to match the same target preamble performance as other UEs in relatively good channel conditions, e.g., the total / effective preamble received power for some UEs is equal to or close to the target (preambleReceivedTargetPower + DELTA_PREAMBLE) for other UEs.

[0155] In this regard, it is preferable that the adjustment on the target preamble received power take into account the number of PRACH transmissions.

[0156] (Analysis 3) Based on the above Analysis 1, if multiple PRACH transmission is triggered only by the transmit power reaching the maximum UE output power limit, the possibility of multiple PRACH transmission being applied may be low. Separate PRACH resources (separate RO resources / separate preamble resources) for multiple PRACH transmission and single PRACH transmission are considered, and the utilization rate of the separate PRACH resources for multiple PRACH transmission may be very low. This is not efficient from a system perspective. In such a case, the condition that the transmit power reaches the maximum UE output power limit is undesirable.

[0157] For different numbers of PRACH transmissions, the total / effective target preamble received power at the base station side may be adjusted, i.e., no restriction may be required according to Analysis 2 and its solution. The results are similar regardless of whether the UE performs a single PRACH transmission with a larger target preamble received power or multiple PRACH transmissions with reduced target preamble received power.

[0158] From this perspective, it is preferable that the UE has multiple options for each RSRP range.

[0159] (Analysis 4) There is insufficient consideration given to how to determine the number of PRACH transmissions for retransmission. Furthermore, there is consideration that the rule for determining the number of PRACH transmissions based on at least one of SSB-RSRP and other factors is applied only to the first RACH attempt. There is insufficient consideration given to taking into account the number of PRACH transmissions in a previous RACH attempt (the repetition level, the determined number of PRACH transmissions) when determining the repetition level of a later RACH attempt.

[0160] (Analysis 5) The restriction on multiple RACH attempts within one RACH procedure has not been adequately considered.

[0161] If a single PRACH transmission is determined for the first RACH attempt, it is considered that a single PRACH transmission will also be applied to any RACH re-attempts within that RACH procedure. If SSB / CSI-RS selection follows existing rules, the UE may select an SSB / CSI-RS with an RSRP lower than the RSRP threshold for triggering multiple PRACH transmissions. In this case, if a single PRACH transmission is considered to be applied to the RACH retry, PRACH performance is not high. It is preferable to extend SSB / CSI-RS selection. Extensions to power ramping are also considered. For example, power ramping may be necessary if the UE selects SSB / CSI-RS for a RACH retry using an RSRP corresponding to multiple PRACH transmissions.

[0162] If multiple PRACH transmissions are decided for the first RACH attempt, it is unclear whether the repetition factor is maintained for RACH retries within that RACH procedure. Similarly, extensions to the SSB / CSI-RS selection rules and power ramping rules are possible. Limitations on the maximum number of preamble transmissions are also possible, taking into account the fact that multiple PRACH transmissions are sent within one RACH attempt.

[0163] Thus, if the operation regarding RACH retry is not thoroughly considered, there is a risk of a decrease in communication throughput.

[0164] Therefore, the present inventors came up with an idea for an operation related to RACH retry.

[0165] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. Each of the following embodiments (e.g., each case) may be used alone or in combination of at least two of them.

[0166] 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."

[0167] 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.

[0168] 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.

[0169] In the present disclosure, the higher layer signaling may be, for example, any one of Radio Resource Control (RRC) signaling, Medium Access Control (MAC) signaling, broadcast information, other messages (e.g., messages from the core network such as positioning protocol (e.g., NR Positioning Protocol A (NRPPa) / LTE Positioning Protocol (LPP)) messages), or a combination thereof.

[0170] 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.

[0171] In the present disclosure, physical layer signaling may be, for example, Downlink Control Information (DCI), Uplink Control Information (UCI), and the like.

[0172] In this disclosure, the following abbreviations may be used: time division multiplexing: TDM; time-division-multiplexed: TDMed; frequency division multiplexing: FDM; frequency-division-multiplexed: FDMed

[0173] In this disclosure, a b, a_b, and a with b added to the bottom right of a may be read interchangeably. c , a^c, and the notation of a with c added to the upper right of a may be read interchangeably. b c , a_b^c, a notation with b added to the bottom right of a and c added to the top right, may be read as interchangeable. In the present disclosure, ceil(x), ceiling function, and ceiling function may be read as interchangeable. In the present disclosure, floor(x), floor function, and floor function may be read as interchangeable.

[0174] In the present disclosure, reference signal (RS), downlink reference signal (DL-RS), SSB / CSI-RS may be interchangeable. In the present disclosure, RSRP, SS-RSRP / CSI-RSRP may be interchangeable. In the present disclosure, RS with RSRP, RS corresponding to RSRP, RS used to measure RSRP, SSB with SS-RSRP, and CSI-RS with CSI-RSRP may be interchangeable.

[0175] In the present disclosure, beam, SSB, SSB index, CSI-RS, CSI-RS resource, CSI-RS resource index, reference signal (RS), QCL assumption, TCI state, unified TCI state, DL or joint TCI state, UL TCI state, UL Tx spatial filter, spatial domain filter, spatial domain transmit filter, spatial domain receive filter, antenna port QCL parameter, QCL parameter, Tx beam, and spatial filter may be read as interchangeable.

[0176] In the present disclosure, RACH resource, RA resource, PRACH preamble, occasion, RACH occasion (RO), PRACH occasion, repetition resource, repetition setting resource, resource configured for RO / repetition, time instance and frequency instance, time resource and frequency resource, RO / preamble resource, repetition, PRACH resource, time / frequency resource for PRACH, preamble setting / index, mask setting / index, PRACH setting may be read as interchangeable.

[0177] In the present disclosure, the terms time occasion, time domain position, time position, PRACH occasion, PRACH slot, period, period, symbol / slot / subframe / frame, at least one index thereof, and time domain index, T#, may be interchangeable. In the present disclosure, the terms frequency domain position, frequency position, subcarrier / RE / RB / CC, at least one index thereof, and frequency domain index, F#, may be interchangeable. In the present disclosure, the terms RO, RO index, and RO# may be interchangeable.

[0178] In the present disclosure, the number of PRACH transmissions, the number of repetitions, the repetition factor, and the aggregation factor K may be interpreted as interchangeable. In the present disclosure, the terms multiple PRACH transmissions, the number of PRACH transmissions being greater than one, and multiple repetitions of PRACH may be interpreted as interchangeable. In the present disclosure, the terms single PRACH transmission and one PRACH transmission may be interpreted as interchangeable.

[0179] In the present disclosure, multiple PRACH transmissions, multiple PRACH transmissions using the same Tx beam, multiple PRACH transmissions using different Tx beams, and multiple PRACH transmissions including multiple PRACH transmissions using the same Tx beam and multiple PRACH transmissions using different Tx beams may be read interchangeably.

[0180] In the present disclosure, single PRACH transmission, legacy PRACH transmission, and legacy PRACH resource configuration may be read interchangeably.

[0181] In the present disclosure, multiple PRACH transmission, new PRACH transmission, and multiple PRACH resource configuration may be interchangeable. In the present disclosure, separated RO, new RO, additional RO, RO for multiple PRACH transmission, and RO separated from RO for existing PRACH transmission may be interchangeable.

[0182] In the present disclosure, the existing RO may include the RO set / determined by RACH-ConfigCommon / RACH-ConfigGeneric / RACH-ConfigDedicated / AdditionalRACH-Config-r17 / additionalRACH-ConfigList-r17.

[0183] In the present disclosure, determining the number of PRACH transmissions may include determining whether to perform a single PRACH transmission or multiple PRACH transmissions. The number of PRACH transmissions may include 1 (single PRACH transmission).

[0184] In the present disclosure, multiple actual PRACH transmissions may mean that the actual number of PRACH transmissions is greater than one after taking into account the possibility of dropping / canceling PRACH transmissions due to at least one of collisions defined in existing specifications and other collisions (e.g., collisions in embodiment B1 / embodiment B2).

[0185] In this disclosure, multiple nominal PRACH transmissions may mean a repetition level greater than one.

[0186] In the present disclosure, one RACH attempt, one single PRACH transmission, and one multiple PRACH transmission may be interchangeable. In the present disclosure, the terms attempt, initial transmission RACH attempt, first RACH attempt, previous RACH attempt, and transmitted RACH attempt may be interchangeable. In the present disclosure, the terms retry, RACH re-attempt, retransmission RACH attempt, later RACH attempt, a RACH attempt other than the first RACH attempt, a second or subsequent RACH attempt, a scheduled RACH attempt, a current RACH attempt, and a RACH attempt after one or more RACH attempts may be interchangeable.

[0187] In the present disclosure, the repetition level, the determined number of PRACH transmissions, the determined number of PRACH transmissions, the number of ROs in an RO group selected for multiple PRACH transmissions, the repetition factor in the RA procedure, the repetition factor in the first RACH attempt, the determined number of PRACH transmissions for the first RACH attempt, and the number of valid ROs in an RO group selected for the first RACH attempt may be read as interchangeable terms.

[0188] In the present disclosure, the actual number of PRACH transmissions, the number of PRACH transmissions, the actual number of PRACH transmissions, the number of PRACH transmissions actually transmitted, and the number of PRACH transmissions transmitted after dropping a PRACH transmission due to a dropping loop may be read as interchangeable.

[0189] In the present disclosure, maximum transmission power, UE maximum transmission power, maximum output power, and UE maximum output power may be read interchangeably.

[0190] In the present disclosure, received power range, RSRP range, SSB / CSI-RS set, whether or not a specific RSRP threshold is exceeded, RSRP range bounded by the RSRP threshold, RSRP corresponding to a single PRACH transmission or multiple PRACH transmissions, and RSRP corresponding to a specific repetition factor may be interpreted as interchangeable.

[0191] (Wireless Communication Method) <Embodiment A1> This embodiment relates to Analysis 1.

[0192] In determining the number of PRACH transmissions, the UE power class is considered in addition to the RSRP threshold. This embodiment addresses the issue in Analysis 1 (i.e., the trigger condition for multiple PRACH transmissions considering the maximum UE output power limit).

[0193] - Example: For determining the number of PRACH transmissions, multiple sets of RSRP thresholds may be configured / indicated. Each set of RSRP thresholds may correspond to a UE power class. For example, if the number of supported UE power classes is X, X sets of RSRP thresholds may be configured / indicated. The UE may use the set corresponding to its power class.

[0194] In the examples of Figures 5A and 5B, the maximum transmit powers for power classes PC1, PC1.5, PC2, and PC3 are 31 dBm, 29 dBm, 26 dBm, and 23 dBm, respectively. The example of Figure 5A shows a set of RSRP thresholds for PC2 {RSRP_0_PC2, RSRP_1_PC2, RSRP_2_PC2}. The example of Figure 5B shows a set of RSRP thresholds for PC3 {RSRP_0_PC3, RSRP_1_PC3, RSRP_2_PC3}. A UE with PC2 uses the RSRP threshold set for PC2, and a UE with PC3 uses the RSRP threshold set for PC3. The RSRP threshold in the set for PC3 may be lower than the RSRP threshold in the set for PC2. Here, x in RSRP_0_x may be any of PC1, PC1.5, PC2, and PC3. In this example, if the RSRP (measurement result) of the SSB / CSI-RS is greater than or equal to RSRP_0_x, the UE determines the number N of PRACH transmissions to be 1. If the RSRP (measurement result) of the SSB / CSI-RS is lower than RSRP_0_x and greater than or equal to RSRP_1_x, the UE determines the number N of PRACH transmissions to be 2. If the RSRP (measurement result) of the SSB / CSI-RS is lower than RSRP_1_x and greater than or equal to RSRP_2_x, the UE determines the number N of PRACH transmissions to be 4. If the RSRP (measurement result) of the SSB / CSI-RS is lower than RSRP_2_x, the UE determines the number N of PRACH transmissions to be 8.

[0195] - Variation 0: Multiple sets of RSRP thresholds may be configured / indicated for determining the number of PRACH transmissions. Each set of RSRP thresholds may correspond to a UE power class and a specific range of the number of previously failed RACH attempts. For example, if the number of supported UE power classes is X, Y (>X) sets of RSRP thresholds may be configured / indicated. One power class may correspond to one or more sets. If one power class corresponds to multiple sets of RSRP thresholds, each set of RSRP thresholds may correspond to a specific range of the number of previously failed RACH attempts. The UE may use the set corresponding to the UE's power class and the number of previously failed RACH attempts.

[0196] - Variation 1 In the above operations, instead of the UE power class, at least one parameter from several variations below may be used to determine the number of PRACH transmissions. Each set of RSRP thresholds may correspond to at least one of the parameter and a specific range of the number of previously failed RACH attempts. -- Variation 1-1: Current UE power class. Since UEs capable of high power (e.g., UE power class 1 / 1.5 / 2) may need to fall back to UE power class 3 depending on the situation, the current UE power class may be used. -- Variation 1-2: ΔP PowerClass This parameter indicates the amount of power reduction due to fallback to power class 3, so this parameter is considered to be used. -- Variation 1-3: P-MPR (P-MPR c , power management maximum power reduction).

[0197] UE power class, a specific range of the number of previous failed RACH attempts, the current UE power class, and ΔP PowerClass A combination of two or more of the P-MPR and the P-MPR may be used to determine the number of PRACH transmissions.

[0198] The UE may determine the number of PRACH transmissions by a combination of this embodiment and embodiment C.

[0199] According to this embodiment, the UE can appropriately determine the number of PRACH transmissions.

[0200] (ΔP PowerClass ) ΔP PowerClassmay be in accordance with the following: if a P-max of 23 dBm or less is indicated, or if the field UECapabilitiesmaxUplinkDutyCycle-PC2-FR1 is not present and the field UECapabilitiesmaxUplinkDutyCycle-MPE-FR1 is not present and the percentage of uplink symbols transmitted within an evaluation period is greater than 50%, or if the field UECapabilitiesmaxUplinkDutyCycle-PC2-FR1 is present and the percentage of uplink symbols transmitted within an evaluation period is greater than maxUplinkDutyCycle-PC2-FR1 (the exact evaluation period is equal to or greater than one radio frame), or if the field UECapabilitiesmaxUplinkDutyCycle-MPE-FR1 is present and half of the percentage of uplink symbols transmitted within an evaluation period is greater than maxUplinkDutyCycle-MPE-FR1 (the exact evaluation period is equal to or greater than one radio frame), ΔP PowerClass is 3 dB for a UE with Power Class 2 capability and 6 dB for a UE with Power Class 1.5 capability. - If a P-max between 23 dBm and 26 dBm is indicated, or if the UECapabilitymaxUplinkDutyCycle-PC2-FR1 field is not present and the UECapabilitymaxUplinkDutyCycle-MPE-FR1 field is not present and the percentage of uplink symbols transmitted in an evaluation period is between 25% and 50%, or if the UECapabilitymaxUplinkDutyCycle-PC2-FR1 field is present and the percentage of uplink symbols transmitted in an evaluation period is between 25% and 50%. If the percentage of symbols is between maxUplinkDutyCycle-PC2-FR1 and maxUplinkDutyCycle-PC2-FR1 / 2 (the exact evaluation period is one radio frame or more), or if the UE capability maxUplinkDutyCycle-MPE-FR1 field is present and the percentage of uplink symbols transmitted within an evaluation period is greater than maxUplinkDutyCycle-MPE-FR1 (the exact evaluation period is one radio frame or more), then ΔPPowerClass is 3 dB for a UE with power class 1.5 capability. If the UE is configured with supplementary uplink (SUL) configuration and the default power class requirements apply on the bands where the UE is indicating power class 2, then ΔP PowerClass - If a PC2 capable UE or a PC1.5 capable UE with txDiversity-r16 capability further indicates SRS-TxSwitch capability 't1r2' or 't1r4' or 't1r1-t1r2' or 't1r1-t1r2-t1r4', ΔP during an SRS transmission occasion with 'antennaSwitching' usage in an SRS resource set where SRS resources consisting of one SRS port are configured in each SRS resource set shall be 3 dB. PowerClass - otherwise, ΔP PowerClass is 0 dB.

[0201] (P-MPR) P-MPR c may be a power management maximum power reduction for the following a and b: (a) compliance with applicable electromagnetic energy absorption requirements in case of simultaneous transmission on multiple RATs for scenarios not in the scope of the specification and to ensure compliance with unwanted emission / self-desensitization requirements, and (b) compliance with applicable electromagnetic energy absorption requirements in case proximity detection is used to address requirements that require a lower maximum output power.

[0202] The UE determines the P-MPR for serving cell c only for the above cases. c In the conformance test performed by the UE, P-MPR c is 0 dB. c is set to P so that the UE can report the maximum available output transmit power to the base station. CMAX,f,c was introduced into the formula: P-MPR c may affect the maximum uplink performance of the selected UL transmission path.

[0203] <Embodiment A2> This embodiment relates to Analysis 2. According to this embodiment, the total / effective target preamble reception power / performance on the base station side can be adjusted for different numbers of PRACH transmissions.

[0204] <<Embodiment A2-1>> A target preamble reception power (separate target preamble reception power) for multiple (actual / nominal) PRACH transmissions separated from a single PRACH transmission may be introduced. The separate target preamble reception power may follow at least one of the following options:

[0205] - Option 2-1-1 Separate target preamble received power parameters for multiple PRACH transmissions (e.g., preambleReceivedTargetPower-Multi-PRACH) are set / indicated.

[0206] PREAMBLE_RECEIVED_TARGET_POWER for multiple (actual / nominal) PRACH transmissions may be calculated by the following formula: PREAMBLE_RECEIVED_TARGET_POWER = preambleReceivedTargetPower-Multi-PRACH + DELTA_PREAMBLE + (PREAMBLE_POWER_RAMPING_COUNTER - 1) × PREAMBLE_POWER_RAMPING_STEP

[0207] - Option 2-1-2 Power reduction offset (e.g., Multi-PRACH-offset) may be configured / indicated by RRC IE / SIB or may be defined by specifications.

[0208] PREAMBLE_RECEIVED_TARGET_POWER for multiple (actual / nominal) PRACH transmissions may be calculated by the following formula: PREAMBLE_RECEIVED_TARGET_POWER = preambleReceivedTargetPower - Multi-PRACH-offset + DELTA_PREAMBLE + (PREAMBLE_POWER_RAMPING_COUNTER - 1) × PREAMBLE_POWER_RAMPING_STEP

[0209] <Embodiment A2-2> Separate target preamble reception powers for different numbers of multiple (actual / nominal) PRACH transmissions may be introduced. The separate target preamble reception powers may follow at least one of the following options:

[0210] - Option 2-2-1 Separate target preamble received power parameters (e.g. preambleReceivedTargetPower-PRACH-Rep2, preambleReceivedTargetPower-PRACH-Rep4, preambleReceivedTargetPower-PRACH-Rep8) for different numbers of multiple (actual / nominal) PRACH transmissions are configured / indicated.

[0211] If there are four (actual / nominal) PRACH transmissions, PREAMBLE_RECEIVED_TARGET_POWER may be calculated by the following formula: PREAMBLE_RECEIVED_TARGET_POWER = preambleReceivedTargetPower-PRACH-Rep4 + DELTA_PREAMBLE + (PREAMBLE_POWER_RAMPING_COUNTER - 1) × PREAMBLE_POWER_RAMPING_STEP

[0212] If the separate target preamble received power parameter for K (actual / nominal) PRACH transmissions is denoted as preambleReceivedTargetPower-PRACH-RepK, then PREAMBLE_RECEIVED_TARGET_POWER for the K (actual / nominal) PRACH transmissions may be calculated by the following formula: PREAMBLE_RECEIVED_TARGET_POWER = preambleReceivedTargetPower-PRACH-RepK + DELTA_PREAMBLE + (PREAMBLE_POWER_RAMPING_COUNTER - 1) × PREAMBLE_POWER_RAMPING_STEP

[0213] - Option 2-2-2 Power reduction offsets (e.g., Multi-PRACH-offset-Rep2, Multi-PRACH-offset-Rep4, Multi-PRACH-offset-Rep8) for different numbers of multiple (actual / nominal) PRACH transmissions may be configured / indicated by an RRC IE / SIB or defined by a specification, e.g., Multi-PRACH-offset-Rep2=3 dB, Multi-PRACH-offset-Rep4=6 dB, Multi-PRACH-offset-Rep8=9 dB.

[0214] If there are four (actual / nominal) PRACH transmissions, PREAMBLE_RECEIVED_TARGET_POWER may be calculated by the following formula: PREAMBLE_RECEIVED_TARGET_POWER = preambleReceivedTargetPower - Multi-PRACH-offset-Rep4 + DELTA_PREAMBLE + (PREAMBLE_POWER_RAMPING_COUNTER - 1) × PREAMBLE_POWER_RAMPING_STEP

[0215] If the separate target preamble received power parameter for K (actual / nominal) PRACH transmissions is denoted as Multi-PRACH-offset-RepK, PREAMBLE_RECEIVED_TARGET_POWER for the K (actual / nominal) PRACH transmissions may be calculated by the following formula: PREAMBLE_RECEIVED_TARGET_POWER = preambleReceivedTargetPower - Multi-PRACH-offset-RepK + DELTA_PREAMBLE + (PREAMBLE_POWER_RAMPING_COUNTER - 1) × PREAMBLE_POWER_RAMPING_STEP

[0216] According to this embodiment, the UE can determine an appropriate target preamble received power for multiple PRACH transmissions.

[0217] <Embodiment A3> This embodiment relates to Analysis 3. According to this embodiment, the restriction that multiple PRACH transmissions can be triggered only by the transmit power reaching the maximum UE output power limit can be relaxed.

[0218] For one or more RSRP thresholds configured / indicated for multiple PRACH transmissions, a particular RSRP range may correspond to multiple operating candidates, and the UE may select one operation from the multiple operating candidates corresponding to the RSRP.

[0219] The multiple operational candidates may refer to multiple sets of at least one of the following parameters: the number of PRACH transmissions, the target preamble received power, and the preamble received power offset (power reduction offset).

[0220] In the example of Figure 6, by setting the RSRP thresholds {RSRP_0, RSRP_1, RSRP_2}, there are ranges 0 where RSRP is equal to or greater than RSRP_0, range 1 where RSRP is lower than RSRP_0 and equal to or greater than RSRP_1, range 2 where RSRP is lower than RSRP_1 and equal to or greater than RSRP_2, and range 3 where RSRP is lower than RSRP_2. The number of PRACH transmissions is represented as N, and the target preamble received power is represented as target_power_x. Range 0 corresponds to one parameter set {N=1} (single PRACH transmission). Range 1 corresponds to three parameter sets {N=1, target_power_1}, {N=2, target_power_2}, and {N=4, target_power_4}. Range 2 corresponds to three parameter sets: {N=2, target_power_2a}, {N=4, target_power_4a}, and {N=8, target_power_8a}. Range 3 corresponds to three parameter sets: {N=2, target_power_2b}, {N=4, target_power_4b}, and {N=8, target_power_8b}. The UE may select a range from ranges 0, 1, 2, or 3 that corresponds to the RSRP measurement result, select one parameter set from the one or more parameter sets corresponding to that range, and apply that one parameter set to PRACH transmission.

[0221] The UE may determine the number of PRACH transmissions by a combination of this embodiment and embodiment C.

[0222] According to this embodiment, the UE can apply an appropriate parameter set to the PRACH transmission depending on the situation.

[0223] <Embodiment B1> Considering the possibility of RO collisions in multiple PRACH transmissions using the same Tx beam, the UE operation may follow at least one of the following options.

[0224] - Option 1: The UE does not expect the first or last (valid) RO in an RO group to be with a collision. Alternatively, the UE does not expect the first or last (valid) RO in any RO group to be with a collision.

[0225] - Option 2: When the UE selects an RO group, collisions are taken into consideration. The UE may follow at least one of the following options: -- Option 2-1: The UE does not determine / select an RO group with the first or last (valid) RO with collision as an RO group for multiple PRACH transmission. -- Option 2-2: If the number of (valid) ROs with collision is greater than or equal to a specific value X, the UE does not determine / select an RO group as an RO group for multiple PRACH transmission. Here, the value of X may be specified by specifications or configured by the base station. -- Option 2-3: If the number of (valid) ROs without collision is less than or equal to a specific value Y, the UE does not determine / select an RO group as an RO group for multiple PRACH transmission. Here, the value of Y may be specified by specifications or configured by the base station.

[0226] - Option 3: Collisions are not considered when the UE selects an RO group. UE behavior after RO group selection is defined. The UE may follow at least one of the following options: -- Option 3-1: If any (valid) RO in an RO group involves a collision, the UE does not transmit PRACH on that RO or cancels the PRACH transmission. The UE may transmit PRACH on the (remaining) valid ROs without collisions in the RO group. -- Option 3-2: If the first or last (valid) RO in an RO group involves a collision, the UE does not transmit PRACH on that RO or cancels the PRACH transmission. -- Option 3-3: If the number of ROs with collisions (valid) in a selected RO group is greater than or equal to a specific value X, the UE does not transmit PRACH in that RO group or cancels PRACH transmission. Here, the value of X may be specified by specifications or configured by the base station. -- Option 3-4: If the number of ROs without collisions (valid) in a selected RO group is less than or equal to a specific value Y, the UE does not transmit PRACH in that RO group or cancels PRACH transmission. Here, the value of Y may be specified by specifications or configured by the base station.

[0227] According to this embodiment, the UE can appropriately control multiple PRACH transmissions even in the presence of possible collisions.

[0228] <Embodiment B2> The definition of "collision" in the terms "with collision" and "without collision" of the present disclosure may include at least one of the following collision cases: - Any symbol indicated as DL by tdd-UL-DL-ConfigurationCommon or tdd-UL-DL-ConfigurationDedicated and its RO overlap. - Any symbol indicated for SS / PBCH block reception by ssb-PositionsInBurst in SIB1 or ssb-PositionsInBurst in ServingCellConfigCommon and its RO overlap. - Any symbol indicated as DL by DCI format 2_0 / SFI and its RO overlap. - Any symbol indicated as flexible by DCI format 2_0 / SFI and its RO overlap. - The RO must overlap with any symbol indicated for PDSCH / CSI-RS reception by the detected DCI. - If the tdd-UL-DL-ConfigurationCommon and tdd-UL-DL-ConfigurationDedicated are configured, and if the tdd-UL-DL-ConfigurationCommon and tdd-UL-DL-ConfigurationDedicated configure a symbol as flexible, and if the UE is configured to monitor DCI format 2_0 / SFI and the UE has not detected DCI format 2_0 / SFI, the RO must overlap with any valid RO for a single PRACH transmission associated with a Type-1 RA procedure in the time / frequency domain. - If the RO must overlap with any valid RO associated with a Type-2 RA procedure in the time / frequency domain, the RO must overlap with any valid RO for a single PRACH transmission associated with a Type-2 RA procedure in the time / frequency domain.- The RO overlaps with any valid PUSCH occasion associated with the Type 2 RA procedure in the time / frequency domain.

[0229] Whether or not a collision case is included among the above several collision cases may be defined by specifications or may be set by the base station.

[0230] This embodiment allows the UE to handle collisions appropriately.

[0231] <Variations of Embodiment B1 / Embodiment B2> Embodiment B1 / Embodiment B2 can be applied to the case of multiple PRACH transmissions using different multiple Tx beams.

[0232] Different options in embodiment B1 / embodiment B2 may be applied to the case of multiple PRACH transmissions using the same Tx beam and the case of multiple PRACH transmissions using different Tx beams. Of the options in embodiment B1 / embodiment B2, the options applied to each case may be defined by specifications or may be set by the base station.

[0233] Embodiment B1 / Embodiment B2 can be applied to multiple PRACH transmissions with a specific RACH type. The specific RACH type may be a specific RACH triggering method, a specific RACH purpose, etc. - Example: Embodiment B1 / Embodiment B2 may be applied to a specific RACH triggering method. The specific RACH triggering method may be, for example, an RA procedure initiated / triggered by the PDCCH / MAC entity / RRC. - Example: Embodiment B1 / Embodiment B2 may be applied to a specific RACH purpose. The specific RACH purpose method may be, for example, at least one of initial access, SI request, SpCell BFR, and reconfiguration with sync.

[0234] <Embodiment C> This embodiment relates to determining the number / times of PRACH transmissions.

[0235] - Embodiment C-1 The determination of the number of PRACH transmissions using the same Tx beam may follow at least one of the following options: -- Option 1: The UE may determine the number of PRACH transmissions based on the selected SSB / CSI-RS and a configured RSRP threshold. The RSRP threshold may be configured for determining the number of PRACH transmissions using the same Tx beam. -- Option 2: The UE may determine the number of PRACH transmissions based on the selected SSB / CSI-RS, a configured RSRP threshold, and the number of past failed attempts. The RSRP threshold may be configured for determining the number of PRACH transmissions using the same Tx beam. The attempts may be attempts using the same Tx beam or attempts for the same selected SSB / CSI-RS. Option 3: The UE may determine the number of PRACH transmissions based on at least one of the number of PRACH transmissions in past attempts, the number of past failed attempts, and the RSRP of the selected SSB / CSI-RS, where the number of PRACH transmissions may be the number of PRACH transmissions using the same Tx beam or the number of PRACH transmissions for the same selected SSB / CSI-RS.

[0236] -- Example 1 Based on Option 1 A base station may configure up to m values ​​for the number of PRACH transmissions using the same Tx beam and may configure (m+1) RSRP thresholds for SSB / CSI-RS for determining the number of PRACH transmissions using the same Tx beam. The m values ​​for the number of PRACH transmissions may be candidate values ​​N_1, N_2, ..., N_m, where N_m > ... > N_2 > N_1 > 1. The (m+1) RSRP thresholds may be RSRP_0, RSRP_1, RSRP_2, ..., RSRP_m, where RSRP_0 > RSRP_1 > RSRP_2 > ... > RSRP_m.

[0237] As in the example of FIG. 7, if the RSRP of the selected SSB / CSI-RS is greater than (or equal to) RSRP_0, the UE may decide to transmit a single PRACH.

[0238] If the RSRP of the selected SSB / CSI-RS is greater than (greater than) RSRP_i and less than (less than) RSRP_i-1, the UE may determine the number of PRACH transmissions as N_i. The UE may transmit multiple PRACH transmissions using PRACH resources configured for multiple PRACH transmissions using the same Tx beam or using PRACH resources configured for a specific number N_i.

[0239] The base station may configure m RSRP thresholds of the SSB / CSI-RS to determine the number of PRACH transmissions using the same Tx beam. The m RSRP thresholds may be RSRP_1, RSRP_2, ..., RSRP_m. Here, RSRP_1 > RSRP_2 >> ... > RSRP_m. If the RSRP of the selected SSB / CSI-RS is greater than (greater than) RSRP_1, the UE may determine a single PRACH transmission. If the RSRP of the selected SSB / CSI-RS is greater than (greater than) RSRP_(i+1) and less than (less than) RSRP_i, the UE may determine the number of PRACH transmissions as N_i. The UE may transmit multiple PRACH transmissions using PRACH resources configured for multiple PRACH transmissions using the same Tx beam or using PRACH resources configured for a specific number N_i.

[0240] -- Example 2-1 Based on Option 2 A base station may configure up to m values ​​for the number of PRACH transmissions using the same Tx beam, and may configure (m+1) RSRP thresholds for SSB / CSI-RS for determining the number of PRACH transmissions using the same Tx beam. The m values ​​for the number of PRACH transmissions may be candidate values ​​N_1, N_2, ..., N_m. Here, N_m > ... > N_2 > N_1 > 1. The (m+1) RSRP thresholds may be RSRP_0, RSRP_1, RSRP_2, ..., RSRP_m. Here, RSRP_0 > RSRP_1 > RSRP_2 > ... > RSRP_m.

[0241] If the RSRP of the selected SSB / CSI-RS is greater than (equal to or greater than) RSRP_0, the UE may follow at least one of the following actions: --- If the number of failed past attempts is less than (equal to or less than) a specific value Z, the UE may decide on a single PRACH transmission. The attempt may be an attempt using the same Tx beam or an attempt for the same selected SSB / CSI-RS. Z may be defined in the specification or may be configured by an RRC IE. --- If the number of failed past attempts is greater than (equal to or greater than) a specific value Z, the UE may decide on the number of PRACH transmissions using the same Tx beam as N_1. The attempt may be an attempt using the same Tx beam or an attempt for the same selected SSB / CSI-RS. Z may be defined in the specification or may be configured by an RRC IE. --- Variation: A set of (m+1) multiple values ​​of Z (Z_1, Z_2, ..., Z_i, ...) may be configured / defined. For example, if the number of failed past attempts is greater than or equal to Z_i, the UE may determine the number of PRACH transmissions using the same Tx beam as N_i. The attempts may be attempts using the same Tx beam or attempts for the same selected SSB / CSI-RS. Z may be defined in the specification or configured by an RRC IE.

[0242] If the RSRP of the selected SSB / CSI-RS is greater than (or equal to) RSRP_i and less than (less than) RSRP_i-1, the UE may follow at least one of the following actions: --- If the number of failed past attempts is less than (or equal to) a specific value Z, the UE may determine the number of PRACH transmissions using the same Tx beam as N_i. The attempts may be attempts using the same Tx beam or attempts for the same selected SSB / CSI-RS. Z may be defined in the specification or may be configured by an RRC IE. --- If the number of failed past attempts is greater than (or equal to) a specific value Z, the UE may determine the number of PRACH transmissions using the same Tx beam as N_i+1 if i<m, and if i=m, the UE may determine the number of PRACH transmissions using the same Tx beam as N_m. The attempts may be attempts using the same Tx beam or attempts for the same selected SSB / CSI-RS. Z may be defined in the specification or configured by an RRC IE. --- Variation: A set of (m+1) multiple values ​​of Z (Z_1, Z_2,..., Z_j,...) may be configured / defined. For example, if the number of failed past attempts is greater than or equal to Z_j, and if (i+j)≦m, the UE may determine the number of PRACH transmissions using the same Tx beam as N_(i+j). If (i+j)>m, the UE may determine the number of PRACH transmissions using the same Tx beam as N_m. The attempts may be attempts using the same Tx beam or attempts for the same selected SSB / CSI-RS. Z may be defined in the specification or configured by an RRC IE.

[0243] -- Example 2-2 Based on Option 2 A base station may configure up to m values ​​for the number of PRACH transmissions using the same Tx beam and may configure multiple sets of RSRP thresholds for SSB / CSI-RS for determining the number of PRACH transmissions using the same Tx beam. The m values ​​for the number of PRACH transmissions may be candidate values ​​N_1, N_2, ..., N_m, where N_m > ... > N_2 > N_1 > 1. Each set may include (m+1) RSRP thresholds RSRP_0, RSRP_1, RSRP_2, ..., RSRP_m, where RSRP_0 > RSRP_1 > RSRP_2 > ... > RSRP_m.

[0244] --- When two sets of RSRP thresholds are configured, if the number of failed past attempts is greater than or equal to a specific value Z, the UE may use the first set of RSRP thresholds to determine the number of PRACH transmissions and follow the procedure in Example 1 of Option 1. --- Variation: More than two sets of RSRP thresholds and (m+1) sets of multiple values ​​of Z (Z_1, Z_2, ..., Z_i, ...) may be configured / defined. For example, if the number of failed past attempts is greater than or equal to Z_i, the UE may use the (i+1)th set of RSRP thresholds and follow the procedure in Example 1 of Option 1.

[0245] -- Example 3 based on Option 3: A new counter for the number of PRACH transmissions using the same Tx beam may be introduced. The counter may be, for example, PRACH_TRANSMISSION_NUMBER. The possible values ​​of the counter may be the same as the possible values ​​for the number of PRACH transmissions (e.g., N_1, N_2, ...). The UE may ramp the number of PRACH transmissions (repetitions).

[0246] For the first PRACH attempt (when the value of PRACH_TRANSMISSION_NUMBER is equal to 1 (or 0)), the UE may determine the number N of PRACH transmissions based on Option 1 (e.g., Example 1) and set the value of PRACH_TRANSMISSION_NUMBER to N.

[0247] In the kth (k>1) PRACH attempt (where the value of PRACH_TRANSMISSION_NUMBER is equal to k1 (or k-1)), if PRACH_TRANSMISSION_NUMBER does not reach the maximum possible value for PRACH transmission (maximum number of PRACH transmissions), the UE may follow at least one of the following examples.

[0248] --- Example 3-1 PRACH_TRANSMISSION_NUMBER is maintained / increased based on PRACH_TRANSMISSION_COUNTER. --- If at least one of the following conditions is met: k is greater than (is greater than or equal to) a specific value K_thres, the RSRP of the selected SSB / CSI-RS is less than (is less than or equal to) a specific value RSRP-thres, and the selected SSB / CSI-RS has not changed since the last attempt, PRACH_TRANSMISSION_NUMBER may be set to the next candidate value for the number of PRACH transmissions. --- Otherwise, PRACH_TRANSMISSION_NUMBER may be maintained. --- Variation: The value of at least one of K_thres and RSRP-thres may be defined in the specification or may be set by an RRC IE. For different values ​​of PRACH_TRANSMISSION_NUMBER, the value of at least one of K_thres and RSRP-thres may be different.

[0249] --- Example 3-2 A new counter (failure counter, Multi_PRACH_TRANSMISSION_FAILURE) may be introduced. The initial value of Multi_PRACH_TRANSMISSION_FAILURE may be 0. PRACH_TRANSMISSION_NUMBER is maintained / increased based on Multi_PRACH_TRANSMISSION_FAILURE. --- If at least one of the following conditions is met: Multi_PRACH_TRANSMISSION_FAILURE is greater than (greater than or equal to) a specific value K_fail; the RSRP of the selected SSB / CSI-RS is less than (less than or equal to) a specific value RSRP-thres; and the selected SSB / CSI-RS has not changed since the last attempt, PRACH_TRANSMISSION_NUMBER may be set to the next candidate value for the number of PRACH transmissions, and Multi_PRACH_TRANSMISSION_FAILURE may be reset to 0. --- Otherwise, PRACH_TRANSMISSION_NUMBER may be maintained and Multi_PRACH_TRANSMISSION_FAILURE may be increased by 1. --- Variation: At least one value of PRACH_TRANSMISSION_NUMBER and Multi_PRACH_TRANSMISSION_FAILURE may be defined in the specification, configured by the RRC IE, or maintained for each SSB / CSI-RS. At least one value of K_thres and RSRP-thres may be defined in the specification or configured by the RRC IE. At least one value of K_thres and RSRP-thres may be different for different values ​​of PRACH_TRANSMISSION_NUMBER.

[0250] In the kth (k>1) PRACH attempt (when the value of PRACH_TRANSMISSION_NUMBER is equal to k1 (or k-1)), if PRACH_TRANSMISSION_NUMBER has not reached the maximum possible value for PRACH transmissions (maximum number of PRACH transmissions), the value of PRACH_TRANSMISSION_NUMBER may be maintained.

[0251] -- Variations If the UE has / reports capability for a maximum number (supported number) of PRACH transmissions using the same Tx beam (the UE has capability for up to X PRACH transmissions using the same Tx beam), the UE may determine the number N of PRACH transmissions using the same Tx beam according to Option 1 / 2 / 3. --- If X≦N, the UE may determine the number of PRACH transmissions using the same Tx beam to be X. --- If X>N, the UE may determine the number of PRACH transmissions using the same Tx beam to be N.

[0252] - Embodiment C-2 Options 1, 2, and 3 of Embodiment C-1 may be applied to determining the number of PRACH transmissions using different Tx beams by replacing "using the same Tx beam" with "using different Tx beams." -- Variation If a UE has / reports the capability of the maximum number (supported number) of PRACH transmissions using different Tx beams (the UE has the capability of up to X PRACH transmissions using different Tx beams), the UE may determine the number N of PRACH transmissions using different Tx beams according to Options 1, 2, and 3 of Embodiment C-1. -- If X≦N, the UE may determine the number of PRACH transmissions using different Tx beams to be X. -- If X>N, the UE may determine the number N of PRACH transmissions using different Tx beams.

[0253] -Embodiment C-3 The UE may determine, based on the RSRP of the selected SSB / CSI-RS, one of the following procedures: a single PRACH transmission procedure, a specific number of PRACH transmission procedures using the same Tx beam, and a specific number of PRACH transmission procedures using different multiple Tx beams.

[0254] --Example A base station may configure up to m values ​​for the number of PRACH transmissions using the same Tx beam, up to n values ​​for the number of PRACH transmissions using multiple different Tx beams, and (m+n+1) RSRP thresholds. The m values ​​for the number of PRACH transmissions may be candidate values ​​K_1, K_2, ..., K_m, where K_m > ... > K_2 > K_1 > 1. The n values ​​for the number of PRACH transmissions may be candidate values ​​K'_1, K'_2, ..., K'_n, where K'_n > ... > K'_2 > K'_1 > 1. The UE may compare the RSRP of the selected SSB / CSI-RS with the multiple RSRP thresholds to determine whether to perform a single PRACH transmission, a specific number of PRACH transmissions using the same Tx beam, or a specific number of PRACH transmissions using multiple different Tx beams.

[0255] As shown in the example of FIG. 8, the (m+n+1) RSRP thresholds may be RSRP_0, RSRP_1, RSRP_2, ..., RSRP_n, RSRP_n+1, RSRP_n+2, ..., RSRP_n+m. Here, RSRP_0 > RSRP_1 > RSRP_2 > ... > RSRP_n > RSRP_n+1 > RSRP_n+2 > ... > RSRP_n+m. If the RSRP of the selected SSB / CSI-RS is greater than (or equal to) RSRP_0, a single PRACH transmission procedure may be determined. If the RSRP of the selected SSB / CSI-RS is less than (or equal to) RSRP_(i-1) and greater than (or equal to) RSRP_i, a K'_i PRACH transmission procedure using different multiple Tx beams may be determined. If the RSRP of the selected SSB / CSI-RS is less than (less than) RSRP_(n+i-1) and greater than (greater than) RSRP_(n+i), a procedure for K_i PRACH transmissions using the same Tx beam may be determined.

[0256] The base station may configure up to m values ​​for the number of PRACH transmissions using the same Tx beam, configure up to n values ​​for the number of PRACH transmissions using different Tx beams, and configure (m+n) RSRP thresholds. The m values ​​for the number of PRACH transmissions may be candidate values ​​K_1, K_2, ..., K_m, where K_m > ... > K_2 > K_1 > 1. The n values ​​for the number of PRACH transmissions may be candidate values ​​K'_1, K'_2, ..., K'_n, where K'_n > ... > K'_2 > K'_1 > 1. The (m+n) RSRP thresholds may be RSRP_1, RSRP_2, ..., RSRP_n, RSRP_n+1, RSRP_n+2, ..., RSRP_n+m. Here, RSRP_1 > RSRP_2 > ... > RSRP_n > RSRP_n+1 > RSRP_n+2 > ... > RSRP_n+m may be satisfied. If the RSRP of the selected SSB / CSI-RS is greater than (or equal to) RSRP_1, a procedure for a single PRACH transmission may be determined. If the RSRP of the selected SSB / CSI-RS is less than (less than) RSRP_i and greater than (or equal to) RSRP_(i+1), a procedure for K'_i PRACH transmissions using different Tx beams may be determined. If the RSRP of the selected SSB / CSI-RS is less than (less than) RSRP_(n+i) and greater than (or equal to) RSRP_(n+i+1), a procedure for K_i PRACH transmissions using the same Tx beam may be determined.

[0257] A UE that is only capable of multiple PRACH transmissions using the same Tx beam, but not multiple PRACH transmissions using different Tx beams, may follow at least one of the following actions: --- The UE may use only the first / last (m+1) values ​​of the multiple RSRP thresholds to decide between a single PRACH transmission procedure and a specific number of PRACH transmissions using the same Tx beam. --- If the UE has / reports the capability of the maximum number (supported number) of PRACH transmissions using the same Tx beam (the UE is capable of up to X PRACH transmissions using the same Tx beam), the UE may determine the number N of PRACH transmissions using the same Tx beam. --- If X≦N, the UE may determine the number of PRACH transmissions using the same Tx beam to be X. ---If X>N, the UE may determine the number of PRACH transmissions using the same Tx beam as N.

[0258] A UE that is only capable of multiple PRACH transmissions using different Tx beams, but not multiple PRACH transmissions using the same Tx beam, may follow at least one of the following actions: --- The UE may use only the first / last (n+1) values ​​of the multiple RSRP thresholds to decide between a single PRACH transmission procedure and a specific number of PRACH transmissions using different Tx beams. --- If the UE has / reports the capability of the maximum number (supported number) of PRACH transmissions using different Tx beams (the UE is capable of up to Y PRACH transmissions using different Tx beams), the UE may determine the number N of PRACH transmissions using different Tx beams. --- If Y≦N, the UE may determine the number Y of PRACH transmissions using different Tx beams. ---If Y>N, the UE may determine that the number of PRACH transmissions using different multiple Tx beams is N.

[0259] -Embodiment C-4 The UE may determine either a procedure for single PRACH transmission or a procedure for multiple PRACH transmission.

[0260] -- Option 1: The UE may decide between a single PRACH transmission procedure and a multiple PRACH transmission procedure based on the RSRP of the selected SSB / CSI-RS and the configured RSRP threshold.

[0261] -- Option 2 The UE may decide between a single PRACH transmission procedure and a multiple PRACH transmission procedure based on the RSRP of the selected SSB / CSI-RS, the configured RSRP threshold, and the number of previous failed attempts.

[0262] -- Example 1 based on Option 1: The base station may configure one RSRP threshold of the SSB / CSI-RS to determine whether to perform a single PRACH transmission procedure or a multiple PRACH transmission procedure. --- If the RSRP of the selected SSB / CSI-RS is greater than (equal to or greater than) the configured RSRP threshold, the UE may determine the single PRACH transmission procedure. --- If the RSRP of the selected SSB / CSI-RS is less than (less than) the configured RSRP threshold, the UE may determine the multiple PRACH transmission procedure.

[0263] -- Example 2-1 based on Option 2 The base station may configure one RSRP threshold for the SSB / CSI-RS to determine whether to perform a single PRACH transmission or a multiple PRACH transmission. -- If the RSRP of the selected SSB / CSI-RS is greater than (equal to or greater than) the configured RSRP threshold, the UE may follow at least one of the following actions: -- If the number of failed attempts in the past is less than (equal to or less than) a specific value Z, the UE may determine the single PRACH transmission procedure. The attempts may be attempts using the same Tx beam or attempts for the same selected SSB / CSI-RS. Z may be defined in the specification or configured by an RRC IE. -- If the number of failed attempts in the past is greater than (equal to or greater than) a specific value Z, the UE may determine the multiple PRACH transmission procedure. The attempts may be attempts using the same Tx beam or attempts for the same selected SSB / CSI-RS. Z may be defined in the specification or may be set by an RRC IE.

[0264] -- Example 2-2 based on Option 2: The base station may configure multiple RSRP thresholds for SSB / CSI-RS to determine whether to perform a single PRACH transmission or a multiple PRACH transmission. Each RSRP threshold may apply to a different number of past failed attempts. -- When two RSRP thresholds are configured, if the number of past failed attempts is greater than / less than a specific value Z, the UE may use the first RSRP threshold to determine whether to perform a single PRACH transmission or a multiple PRACH transmission. The attempts may use the same Tx beam or may be for the same selected SSB / CSI-RS. Z may be defined in the specification or configured by an RRC IE. --- Variation: More than two RSRP thresholds and a set of (m+1) multiple values ​​of Z (Z_1, Z_2, ..., Z_i, ...) may be configured / defined. For example, if the number of past failed attempts is greater than or equal to Z_i, the UE may use the (i+1)th RSRP threshold to decide between a single PRACH transmission procedure and a multiple PRACH transmission procedure.

[0265] According to this embodiment, the UE can determine the appropriate number of PRACH transmissions.

[0266] <Embodiment D0> This embodiment relates to a method for determining the number of PRACH transmissions (repetition level) within a RACH attempt other than the first RACH attempt.

[0267] The determination of the repetition level of RACH attempts other than the first RACH attempt may follow at least one of several options: - Option 0: The repetition level of each RACH attempt is determined independently according to the same rules as those for determining the repetition level of the first RACH attempt; - Option 1: The repetition level of a repeat RACH attempt depends on the repetition level of the last or first RACH attempt; - Option 2: The repetition level of a repeat RACH attempt depends on the repetition level of the last or first RACH attempt, if any, with the same SSB / CSI-RS (Reference Signal / Tx Beam / TCI State) selection as the SSB / CSI-RS selection in the repeat RACH attempt.

[0268] A retransmission RACH attempt may include any RACH attempt other than the initial RACH attempt. A retransmission RACH attempt may be a RACH attempt with a preamble transmission counter (PREAMBLE_TRANSMISSION_COUNTER) greater than 1. A retransmission RACH attempt may be triggered by a failure to receive an RAR or a failure to receive a contention resolution.

[0269] FIG. 9 shows an example of multiple RACH attempts. After the first through (n+1) RACH attempts are performed (after the first through (n+1) RACH attempts fail), the UE performs the (n+2) RACH attempt. In the first and (n+1) RACH attempts, the UE may select SSB / CSI-RS #1 and use a Tx beam (TCI state) based on the reference signal for each PRACH transmission within that RACH attempt. In the n RACH and (n+2) RACH attempts, the UE may select SSB / CSI-RS #2 and use a Tx beam (TCI state) based on the reference signal for each PRACH transmission within that RACH attempt. In Option 0, the repetition level for the (n+2)th RACH attempt is determined independently (according to the same decision rule) as the previous (up to (n+1)th) RACH attempts. In Option 1, if the repetition level of a retransmission RACH attempt depends on the repetition level of the last RACH attempt, the repetition level for the (n+2)th RACH attempt is determined based on the last ((n+1)th) RACH attempt. In Option 2, if the repetition level of a retransmission RACH attempt depends on the repetition level of the last RACH attempt with the same SSB / CSI-RS selection, the repetition level for the (n+2)th RACH attempt with SSB / CSI-RS#2 selected is determined based on the last (nth) RACH attempt based on the same SSB / CSI-RS#2.

[0270] <Embodiment D1> This embodiment relates to details of option 1 of embodiment D0.

[0271] In option 1, the UE may follow at least one of the following cases of behavior:

[0272] Case 1: The repetition level of the last or first RACH attempt is equal to 1 (a single PRACH transmission was determined in the last or first RACH attempt). In this case, the UE may determine the repetition level of the current RACH attempt based on the decision rule for determining the repetition level of the first RACH attempt. The decision rule may determine the repetition level based on at least one of the SSB-RSRP, the UE power class, and the UE maximum transmit power.

[0273] - Case 2: The repetition level of the last or first RACH attempt is greater than 1 (multiple PRACH transmissions were determined in the last or first RACH attempt). In this case, the UE may determine the repetition level of the current RACH attempt based on the repetition level of the last or first RACH attempt. The repetition level of the current RACH attempt may follow at least one of the following options: -- Option 1-1: The repetition level of the retransmission RACH attempt may be the same as the repetition level of the last or first RACH attempt. -- Option 1-2: The repetition level of the retransmission RACH attempt may be increased based on the repetition level of the last or first RACH attempt.

[0274] <Embodiment D1-1> In the above-described Case 2, whether Option 1-1 or Option 1-2 is applied may be determined based on a condition. For example, if a specific condition (a repetition level increase condition) is met, Option 1-2 may be applied, and if not, Option 1-1 may be applied. If Option 1-2 is applied, the repetition level of the RACH attempt may be increased (the repetition level of the current RACH attempt may be increased from the repetition level of the last or first RACH attempt). If Option 1-1 is applied, the repetition level of the RACH attempt may be maintained (the repetition level of the current RACH attempt may be equal to the repetition level of the last or first RACH attempt). The specific condition may be one of the following conditions, or a condition obtained by an AND / OR operation of at least two of the following conditions:

[0275] Condition 1: The repetition level of the last or first RACH attempt has not reached the maximum number set for the number of PRACH transmissions. Example: If the repetition level X of the last or first RACH attempt has reached the maximum number set for the number of PRACH transmissions, the repetition level of the current RACH attempt is not increased from X (equal to X); otherwise, the repetition level of the current RACH attempt is increased from X.

[0276] Condition 2: The selected SSB / CSI-RS is not changed since the selection of SSB / CSI-RS in the last or first RACH attempt. Example: If the selected SSB / CSI-RS is not changed since the selection of SSB / CSI-RS in the last or first RACH attempt, the repetition level of the current RACH attempt is increased from the repetition level X of the last or first RACH attempt; otherwise, the repetition level of the current RACH attempt is not increased from X.

[0277] Condition 3: The actual number of PRACH transmissions in the last or first RACH attempt is equal to Y (or is greater than Y, or is less than Y). Here, the value of Y may be defined in the specification or may be set / instructed by the base station. For example, Y may be 1 or a number greater than 1. Example: If the actual number of PRACH transmissions Z in the last or first RACH attempt is greater than or less than Y, the repetition level of the current RACH attempt is not increased from the repetition level X of the last or first RACH attempt; otherwise, the repetition level of the current RACH attempt is increased from X.

[0278] Condition 4: The actual number of PRACH transmissions in the last or first RACH attempt is equal to (or less than) the repetition level of the last or first RACH attempt. Example: If the actual number Z of PRACH transmissions in the last or first RACH attempt is less than the repetition level X of the last or first RACH attempt (at least one PRACH transmission is dropped due to a dropping rule), the repetition level of the current RACH attempt is not increased from X; otherwise, the repetition level of the current RACH attempt is increased from X. The dropping rule may be specified in the random access channel specification of the control physical layer procedures.

[0279] Condition 5: The transmission power reaches the maximum transmission power within the last RACH attempt. Example: If the transmission power reaches the maximum transmission power within the last RACH attempt, the repetition level of the current RACH attempt is not increased from the repetition level X of the last or first RACH attempt, otherwise the repetition level of the current RACH attempt is increased from X.

[0280] Condition 6: The transmit power within the current RACH attempt, determined by assuming that the repetition level of the current RACH attempt is the same as the repetition level of the last or first RACH attempt, reaches the maximum transmit power. Example: If the transmit power within the current RACH attempt, determined by assuming that the repetition level of the current RACH attempt is the same as the repetition level of the last or first RACH attempt, reaches the maximum transmit power, then the determined number of PRACH transmissions within the current RACH attempt is not increased from the repetition level X of the last or first RACH attempt; otherwise, the repetition level of the current RACH attempt is increased from X.

[0281] The condition for repeatedly increasing the level in the above-mentioned case 2 may be any combination of conditions 1, 2, 3, 4, 5, and 6. The combination of conditions may include at least one of the following examples.

[0282] Example: Condition 1 AND Condition 2 If the SSB or CSI-RS selected in the current RACH attempt is not changed from the SSB or CSI-RS selected in the last or first RACH attempt and the repetition level of the last or first RACH attempt is less than the configured maximum number for the number of PRACH transmissions, then the repetition level of the current RACH attempt is increased from the repetition level X of the last or first RACH attempt; otherwise, the repetition level of the current RACH attempt is equal to X.

[0283] Example: Condition 1 AND Condition 2 AND Condition 4 If the SSB or CSI-RS selected in the current RACH attempt is not changed from the SSB or CSI-RS selected in the last or first RACH attempt, and the repetition level of the last or first RACH attempt is less than the configured maximum number for the number of PRACH transmissions, and the actual number of PRACH transmissions in the last or first RACH attempt is equal to the repetition level X of the last or first RACH attempt, then the repetition level of the current RACH attempt is increased from the repetition level X of the last or first RACH attempt; otherwise, the repetition level of the current RACH attempt is equal to X.

[0284] Example: Condition 1 AND Condition 2 AND Condition 5 If the SSB or CSI-RS selected in the current RACH attempt is not changed from the SSB or CSI-RS selected in the last or first RACH attempt, and the repetition level of the last or first RACH attempt is less than the configured maximum number for the number of PRACH transmissions, and the transmit power in the last RACH attempt has reached the maximum transmit power, then the repetition level of the current RACH attempt is increased from the repetition level X of the last or first RACH attempt; otherwise, the repetition level of the current RACH attempt is equal to X.

[0285] Example: Condition 1 AND Condition 2 AND Condition 6 If the SSB or CSI-RS selected in the current RACH attempt is not changed from the SSB or CSI-RS selected in the last or first RACH attempt, and the repetition level of the last or first RACH attempt is less than the configured maximum number for the number of PRACH transmissions, and the transmit power within the current RACH attempt reaches the maximum transmit power, which is determined by assuming that the repetition level of the current RACH attempt is the same as the repetition level of the last or first RACH attempt, then the repetition level of the current RACH attempt is increased from the repetition level X of the last or first RACH attempt; otherwise, the repetition level of the current RACH attempt is equal to X.

[0286] <<Embodiment D1-2>> In the above-described Case 2, when Option 1-2 is applied (the repetition level is increased), the repetition level after the increase may be determined according to at least one of the following options.

[0287] Option 1-2a: The repetition level of the current RACH attempt is increased to the lowest repetition level among one or more candidate repetition levels that are greater than the repetition level of the last or first RACH attempt among the configured candidate repetition levels.

[0288] For example, if candidate repetition levels {K0, K1, K2, K3} (K0 < K1 < K2 < K3) for multiple PRACH transmissions are configured by the base station, and the repetition level of the last or first RACH attempt is K1, and the repetition level increase condition is met, the UE may determine the repetition level of the current RACH attempt to be K2.

[0289] Option 1-2b: The repetition level of the current RACH attempt is increased to the lowest repetition level among the configured candidate repetition levels, if there are one or more candidate repetition levels that are higher than the repetition level of the last or first RACH attempt and that are obtained by assuming that the calculated transmit power does not exceed the UE maximum transmit power.

[0290] If none of the configured candidate repetition levels meets the conditions necessary for the PRACH transmission power to not exceed the UE maximum transmission power, the increased repetition level may be determined to be the maximum repetition level among the configured candidate repetition levels.

[0291] For example, if candidate repetition levels {K0, K1, K2, K3} (K0 < K1 < K2 < K3) for multiple PRACH transmissions are configured by the base station, and the repetition level of the last or first RACH attempt is K0, and a repetition level increase condition is met, the UE may follow at least one of the following actions: - If the determined transmit power exceeds the UE maximum transmit power when the repetition level of the current RACH attempt is assumed to be K1, but does not exceed the UE maximum transmit power when the repetition level of the current RACH attempt is assumed to be K2 or K3, the UE may determine the repetition level within the current RACH attempt to be K2. - If the determined transmit power exceeds the UE maximum transmit power when the repetition level of the current RACH attempt is assumed to be K1, K2, or K3, the UE may determine the repetition level within the current RACH attempt to be K3.

[0292] <<Variation>> When a specific condition (repetition level increase condition) in embodiment D1-1 is satisfied, the UE may determine the repetition level of the current RACH attempt based on the decision rule used to determine the repetition level of the initial RACH attempt. The decision rule may determine the repetition level based on at least one of SSB-RSRP, UE power class, and UE maximum transmit power.

[0293] According to this embodiment, the UE can appropriately determine the repetition level of the retransmission RACH attempt based on the repetition level of the last or first RACH attempt.

[0294] <Embodiment D2> This embodiment relates to details of option 2 of embodiment D0.

[0295] In option 2, the UE may follow at least one of the following cases of behavior:

[0296] Case 1: There is no previous RACH attempt with the same SSB / CSI-RS selection as the SSB / CSI-RS selection of the current RACH attempt. In this case, the UE may determine the repetition level of the current RACH attempt based on the decision rule used to determine the repetition level of the first RACH attempt. The decision rule may determine the repetition level based on at least one of the SSB-RSRP, the UE power class, and the UE maximum transmit power.

[0297] Case 2: There is a previous RACH attempt with the same SSB / CSI-RS selection as the SSB / CSI-RS selection of the current RACH attempt, and the repetition level of the last or first RACH attempt with the same SSB / CSI-RS selection is equal to 1 (a single PRACH transmission was determined in the last or first RACH attempt with the same SSB / CSI-RS selection). In this case, the UE may determine the repetition level of the current RACH attempt based on the decision rule used to determine the repetition level of the first RACH attempt. The decision rule may determine the repetition level based on at least one of the SSB-RS SRP, the UE power class, and the UE maximum transmit power.

[0298] - Case 3: There is a previous RACH attempt with the same SSB / CSI-RS selection as the SSB / CSI-RS selection of the current RACH attempt, and the repetition level of the last or first RACH attempt with the same SSB / CSI-RS selection is greater than 1 (multiple PRACH transmissions were determined in the last or first RACH attempt with the same SSB / CSI-RS selection). In this case, the UE may determine the repetition level of the current RACH attempt based on the repetition level of the last or first RACH attempt with the same SSB / CSI-RS selection. In this case, the UE may determine the repetition level of the current RACH attempt according to at least one of the following options: -- Option 2-1: The repetition level of the retransmission RACH attempt (current RACH attempt) may be the same as the repetition level of the last or first RACH attempt with the same SSB / CSI-RS selection. -- Option 2-2: The repetition level of the retransmission RACH attempt (current RACH attempt) may be increased based on the repetition level of the last or first RACH attempt with that same SSB / CSI-RS selection.

[0299] In Case 3, whether to maintain or increase the repetition level based on the repetition level of the last or first RACH attempt with the same SSB / CSI-RS selection may be based on a condition. For example, if a specific condition (a repetition level increase condition) is met, Option 2-2 may be applied; otherwise, Option 2-1 may be applied. If Option 2-2 is applied, the repetition level of the RACH attempt may be increased (the repetition level of the current RACH attempt may be increased from the repetition level of the last or first RACH attempt with the same SSB / CSI-RS selection). If Option 2-1 is applied, the repetition level of the RACH attempt may be maintained (the repetition level of the current RACH attempt may be equal to the repetition level of the last or first RACH attempt with the same SSB / CSI-RS selection). The specific condition may reuse / apply the specific condition of Embodiment D1-1 by replacing "the last or first RACH attempt" with "the last or first RACH attempt with the same SSB / CSI-RS selection."

[0300] In case 3, when option 2-2 is applied (the repetition level is increased), the determination of the increased repetition level may be made by reusing / adapting the determination method of embodiment D1-2, replacing "the last or first RACH attempt" with "the last or first RACH attempt with the same SSB / CSI-RS selection."

[0301] <<Variation>> When the "last or first RACH attempt" is replaced with the "last or first RACH attempt with the same SSB / CSI-RS selection" and a specific condition in embodiment D1-1 is met, the UE may determine the repetition level of the current RACH attempt based on the decision rule used to determine the repetition level of the first RACH attempt. The decision rule may determine the repetition level based on at least one of the SSB-RSRP, the UE power class, and the UE maximum transmit power.

[0302] According to this embodiment, the UE can appropriately determine the repetition level of the retransmission RACH attempt based on the last or first RACH attempt with the same SSB / CSI-RS selection as the SSB / CSI-RS selection in the retransmission RACH attempt.

[0303] <Embodiment 0> In some of the following embodiments, the operation of the UE to determine whether to perform a single PRACH transmission or multiple PRACH transmissions for a certain RACH attempt based on the RSRP of the SSB / CSI-RS and the operation of determining the number of PRACH transmissions for a certain RACH attempt based on the RSRP of the SSB / CSI-RS may be in accordance with at least one of the above embodiments A to D.

[0304] Embodiment 1 This embodiment relates to the case where a single PRACH transmission is decided.

[0305] The specification may specify that if a single PRACH transmission is determined for the first RACH attempt, the single PRACH transmission is applied to one or more RACH attempts within the RA procedure. The operation in this case may be in accordance with at least one of several embodiments 1-x below.

[0306] <<Embodiment 1-1>> The SSB / CSI-RS selection in the RACH retry in this case may follow at least one of the following options.

[0307] - Option 0: SSB / CSI-RS selection is the same as the existing SSB / CSI-RS selection rules. -- The existing SSB / CSI-RS selection rules are as follows: -- If there is an SSB / CSI-RS with an RSRP above the threshold (rsrp-ThresholdSSB / rsrp-ThresholdCSI-RS), the UE selects that SSB / CSI-RS; otherwise, the UE selects any SSB / CSI-RS. -- The UE can select an SSB / CSI-RS with an RSRP lower than the RSRP threshold for triggering multiple PRACH transmissions. In this case, assuming that a single PRACH transmission is applied to RACH retries, the PRACH performance is not high.

[0308] - Option 1: The UE prioritizes SSB / CSI-RS with RSRP corresponding to a single PRACH transmission, followed by SSB / CSI-RS with RSRP corresponding to multiple PRACH transmissions. In other words, the UE prioritizes SSB / CSI-RS with RSRP above a threshold corresponding to a single PRACH transmission, followed by SSB / CSI-RS with RSRP above a threshold corresponding to multiple PRACH transmissions. In this case, the UE may follow at least one of the following examples.

[0309] -- Example 1: As in the example of Figure 10, an existing threshold rsrp-ThresholdSSB / rsrp-ThresholdCSI-RS and a higher threshold RSRP_thr0 may be configured / defined. If there is an SSB / CSI-RS with an RSRP greater than RSRP_thr0 in the first RACH attempt, the UE may decide to perform a single PRACH transmission for the first RACH attempt. If there is no SSB / CSI-RS with an RSRP greater than RSRP_thr0 in the first RACH attempt, the UE may decide to perform a multiple PRACH transmission for the first RACH attempt. The UE may follow at least one of the following examples.

[0310] --- Example 1-1: If there is at least one (associated) SSB / CSI-RS with an RSRP exceeding RSRP_thr0, the UE may select one SSB / CSI-RS with an RSRP exceeding RSRP_thr0. Otherwise, if there is at least one (associated) SSB / CSI-RS with an RSRP exceeding rsrp-ThresholdSSB / rsrp-ThresholdCSI-RS, the UE may select one SSB / CSI-RS with an RSRP exceeding rsrp-ThresholdSSB / rsrp-ThresholdCSI-RS. Otherwise, the UE may select any SSB / CSI-RS.

[0311] --- Example 1-2: An SSB / CSI-RS with an RSRP exceeding RSRP_thr0 may be identified as SSB / CSI-RS Set #0. An SSB / CSI-RS with an RSRP not exceeding RSRP_thr0 but exceeding rsrp-ThresholdSSB / rsrp-ThresholdCSI-RS may be identified as SSB / CSI-RS Set #1. An SSB / CSI-RS with an RSRP not exceeding rsrp-ThresholdSSB / rsrp-ThresholdCSI-RS may be identified as SSB / CSI-RS Set #2. If there are SSB / CSI-RS in SSB / CSI-RS Set #0 for SSB / CSI-RS selection, the UE may prioritize SSB / CSI-RS Set #0. If there is no SSB / CSI-RS in SSB / CSI-RS Set #0, the UE may prioritize SSB / CSI-RS Set #1. If there is no SSB / CSI-RS in SSB / CSI-RS Set #1, the UE may select any SSB / CSI-RS or may select an SSB / CSI-RS in SSB / CSI-RS Set #2.

[0312] -- Example 2: The existing thresholds rsrp-ThresholdSSB / rsrp-ThresholdCSI-RS and a lower threshold RSRP_thr0 may be configured / defined. If there is an SSB / CSI-RS with an RSRP exceeding the thresholds rsrp-ThresholdSSB / rsrp-ThresholdCSI-RS in the first RACH attempt, the UE may decide to perform a single PRACH transmission for the first RACH attempt. If there is no SSB / CSI-RS with an RSRP exceeding the thresholds rsrp-ThresholdSSB / rsrp-ThresholdCSI-RS in the first RACH attempt, the UE may decide to perform a multiple PRACH transmission for the first RACH attempt. The UE may follow at least one of the following examples.

[0313] --- Example 2-1: If there is at least one (associated) SSB / CSI-RS with an RSRP exceeding rsrp-ThresholdSSB / rsrp-ThresholdCSI-RS, the UE may select one SSB / CSI-RS with an RSRP exceeding rsrp-ThresholdSSB / rsrp-ThresholdCSI-RS. Otherwise, if there is at least one (associated) SSB / CSI-RS with an RSRP exceeding RSRP_thr0, the UE may select one SSB / CSI-RS with an RSRP exceeding RSRP_thr0. Otherwise, the UE may select any SSB / CSI-RS.

[0314] - Option 2: The UE prioritizes SSB / CSI-RS with RSRP corresponding to a single PRACH transmission, followed by SSB / CSI-RS with RSRP corresponding to a smaller repetition factor. In this case, the UE may follow the example below.

[0315] Example 1: As shown in the example of Figure 11, the existing thresholds rsrp-ThresholdSSB / rsrp-ThresholdCSI-RS, higher thresholds RSRP_thr2, higher thresholds RSRP_thr1, and higher thresholds RSRP_thr0 may be configured / defined. If there are SSB / CSI-RS with RSRP exceeding RSRP_thr0 in the first RACH attempt, the UE may determine a single PRACH transmission for the first RACH attempt. If there are no SSB / CSI-RS with RSRP exceeding RSRP_thr0 in the first RACH attempt, the UE may determine multiple PRACH transmissions for the first RACH attempt. If there are SSB / CSI-RS with RSRP not exceeding RSRP_thr0 but exceeding RSRP_thr1 in the first RACH attempt, the UE may determine the number of PRACH transmissions for the first RACH attempt to be two. If there are SSB / CSI-RS with RSRP not exceeding RSRP_thr1 but exceeding RSRP_thr2 in the first RACH attempt, the UE may determine the number of PRACH transmissions for the first RACH attempt to be 4. If there are no SSB / CSI-RS with RSRP exceeding RSRP_thr2, the UE may determine the number of PRACH transmissions for the first RACH attempt to be 8. The UE may follow at least one of the following examples.

[0316] --- Example 1-1: If there is at least one (associated) SSB / CSI-RS with an RSRP greater than RSRP_thr0, the UE may select one SSB / CSI-RS with an RSRP greater than RSRP_thr0. Otherwise, if there is at least one (associated) SSB / CSI-RS with an RSRP greater than RSRP_thr1, the UE may select one SSB / CSI-RS with an RSRP greater than RSRP_thr1. Alternatively, if there is at least one (associated) SSB / CSI-RS with an RSRP greater than RSRP_thr2, the UE may select one SSB / CSI-RS with an RSRP greater than RSRP_thr2. Otherwise, if there is at least one (associated) SSB / CSI-RS with RSRP above rsrp-ThresholdSSB / rsrp-ThresholdCSI-RS, the UE may select one SSB / CSI-RS with RSRP above rsrp-ThresholdSSB / rsrp-ThresholdCSI-RS. Otherwise, the UE may select any SSB / CSI-RS.

[0317] --- Example 1-2: An SSB / CSI-RS having an RSRP greater than RSRP_thr0 may be identified as SSB / CSI-RS Set #0. An SSB / CSI-RS having an RSRP not greater than RSRP_thr0 but greater than RSRP_thr1 may be identified as SSB / CSI-RS Set #1. An SSB / CSI-RS having an RSRP not greater than RSRP_thr1 but greater than RSRP_thr2 may be identified as SSB / CSI-RS Set #2. An SSB / CSI-RS having an RSRP not greater than RSRP_thr2 but greater than rsrp-ThresholdSSB / rsrp-ThresholdCSI-RS may be identified as SSB / CSI-RS Set #3. An SSB / CSI-RS with an RSRP not exceeding rsrp-ThresholdSSB / rsrp-ThresholdCSI-RS may be identified as SSB / CSI-RS Set #4. If there is an SSB / CSI-RS in SSB / CSI-RS Set #0 for SSB / CSI-RS selection, the UE may prioritize SSB / CSI-RS Set #0. If there is no SSB / CSI-RS in SSB / CSI-RS Set #0, the UE may prioritize SSB / CSI-RS Set #1. If there is no SSB / CSI-RS in SSB / CSI-RS Set #0 and #1, the UE may prioritize SSB / CSI-RS Set #2. If there is no SSB / CSI-RS in SSB / CSI-RS Sets #0 to #2, the UE may prioritize SSB / CSI-RS Set #3. If there is no SSB / CSI-RS in SSB / CSI-RS Sets #0 to #3, the UE may select any SSB / CSI-RS or may select an SSB / CSI-RS in SSB / CSI-RS Set #4.

[0318] -- Example 2: The existing thresholds rsrp-ThresholdSSB / rsrp-ThresholdCSI-RS, a lower threshold RSRP_thr1, a lower threshold RSRP_thr2, and a higher threshold RSRP_thr3 may be configured / defined. If there is an SSB / CSI-RS with an RSRP exceeding rsrp-ThresholdSSB / rsrp-ThresholdCSI-RS in the first RACH attempt, the UE may determine single-PRACH transmission for the first RACH attempt. If there is no SSB / CSI-RS with an RSRP exceeding rsrp-ThresholdSSB / rsrp-ThresholdCSI-RS in the first RACH attempt, the UE may determine multiple-PRACH transmission for the first RACH attempt. If there are SSB / CSI-RS with RSRPs that do not exceed rsrp-ThresholdSSB / rsrp-ThresholdCSI-RS and exceed RSRP_thr1 in the first RACH attempt, the UE may determine the number of PRACH transmissions for the first RACH attempt to be 2. If there are SSB / CSI-RS with RSRPs that do not exceed RSRP_thr1 and exceed RSRP_thr2 in the first RACH attempt, the UE may determine the number of PRACH transmissions for the first RACH attempt to be 4. If there are no SSB / CSI-RS with RSRPs that exceed RSRP_thr2, the UE may determine the number of PRACH transmissions for the first RACH attempt to be 8. The UE may follow at least one of the following examples.

[0319] --- Example 2-1: If there is at least one (associated) SSB / CSI-RS with an RSRP exceeding rsrp-ThresholdSSB / rsrp-ThresholdCSI-RS, the UE may select one SSB / CSI-RS with an RSRP exceeding rsrp-ThresholdSSB / rsrp-ThresholdCSI-RS. Otherwise, if there is at least one (associated) SSB / CSI-RS with an RSRP exceeding RSRP_thr1, the UE may select one SSB / CSI-RS with an RSRP exceeding RSRP_thr1. Alternatively, if there is at least one (associated) SSB / CSI-RS with an RSRP exceeding RSRP_thr2, the UE may select one SSB / CSI-RS with an RSRP exceeding RSRP_thr2. Otherwise, if there is at least one (associated) SSB / CSI-RS with an RSRP greater than RSRP_thr3, the UE may select one SSB / CSI-RS with an RSRP greater than RSRP_thr3, otherwise the UE may select any SSB / CSI-RS.

[0320] <<Embodiment 1-2>> Power ramping in RACH retry in this case may follow at least one of the following options.

[0321] - Option 1: Existing power ramping rules can be reused / repurposed. -- The existing power ramping rules are: -- If the selected SSB / CSI-RS has not changed from the selection in the last RACH attempt, the UE increments PREAMBLE_POWER_RAMPING_COUNTER by 1. If the selected SSB / CSI-RS has changed from the selection in the last RACH attempt, the UE maintains PREAMBLE_POWER_RAMPING_COUNTER.

[0322] - Option 2: An extended power ramping rule is applied, which is based on the RSRP threshold for determining the number of PRACH transmissions and the RSRP of the selected SSB / CSI-RS. The UE may follow the following rules:

[0323] Rule: If the RSRP of the selected SSB / CSI-RS corresponds to multiple PRACH transmissions, the UE may follow at least one of the following actions. As in embodiment 1-1, whether the RSRP corresponds to multiple PRACH transmissions or single PRACH transmissions may be determined based on a threshold. If the selected SSB / CSI-RS has not changed from the selection in the last RACH attempt, the UE may increment the PREAMBLE_POWER_RAMPING_COUNTER by X, where X may be equal to or greater than 1. X may be defined by the specification or may be indicated / set by the base station. If the selected SSB / CSI-RS has changed from the selection in the last RACH attempt, the UE may increment the PREAMBLE_POWER_RAMPING_COUNTER by Y, where Y may be equal to or greater than 0. Y may be defined by the specification or may be indicated / set by the base station. --- Variation: The values ​​of X and Y may depend on the value of the repetition factor corresponding to the selected SSB / CSI-RS (the values ​​of X and Y may be different for different values ​​of that repetition factor).

[0324] -- The RSRP of the selected SSB / CSI-RS does not necessarily exceed the threshold for a single PRACH transmission. This extension allows for power increase when no SSB / CSI-RS has an RSRP exceeding the threshold corresponding to a single PRACH transmission.

[0325] According to this embodiment, if a single PRACH transmission is decided for the first RACH attempt, the UE may appropriately perform SSB / CSI-RS selection and / or power ramping for one or more RACH attempts within that RA procedure.

[0326] Second Embodiment This embodiment relates to a case where the number of PRACH transmissions is maintained in RACH retry when multiple PRACH transmissions are determined.

[0327] If multiple PRACH transmissions are determined for the first RACH attempt, the specification may specify that multiple PRACH transmissions are applied to one or more RACH attempts within the RAC procedure, and the number of PRACH transmissions in the RACH retry attempts is the same as the number of PRACH transmissions in the first RACH attempt. The operation in this case may be in accordance with at least one of the following embodiments 2-x.

[0328] <<Embodiment 2-1>> The SSB / CSI-RS selection in the RACH retry in this case may follow at least one of the following options.

[0329] - Option 1-0: SSB / CSI-RS selection is the same as the existing SSB / CSI-RS selection rule. -- The existing SSB / CSI-RS selection rule is as follows: -- If there is an SSB / CSI-RS with an RSRP above the threshold (rsrp-ThresholdSSB / rsrp-ThresholdCSI-RS), the UE selects that SSB / CSI-RS; otherwise, the UE selects any SSB / CSI-RS. -- The UE can select an SSB / CSI-RS with an RSRP lower than the RSRP threshold for triggering multiple PRACH transmissions. In this case, assuming that a single PRACH transmission is applied to RACH retries, the PRACH performance is not high.

[0330] - Option 1-1: The UE prioritizes the SSB / CSI-RS with an RSRP corresponding to a repetition factor equal to the repetition factor in the first RACH attempt, then prioritizes the SSB / CSI-RS with an RSRP corresponding to a repetition factor smaller than and closest to the repetition factor in the first RACH attempt, then prioritizes the SSB / CSI-RS with an RSRP corresponding to a repetition factor larger than and closest to the repetition factor in the first RACH attempt.

[0331] - Option 1-2: The UE prioritizes SSB / CSI-RS with RSRP corresponding to a repetition factor less than or equal to the repetition factor of the first RACH attempt, then prioritizes SSB / CSI-RS with RSRP corresponding to a repetition factor greater than and closest to the repetition factor of the first RACH attempt.

[0332] - Option 1-3: The UE prioritizes SSB / CSI-RS with RSRP corresponding to a repetition factor equal to the repetition factor in the first RACH attempt, then prioritizes SSB / CSI-RS with RSRP corresponding to a repetition factor smaller and closest to the repetition factor in the first RACH attempt, then prioritizes SSB / CSI-RS with RSRP corresponding to a repetition factor larger than the repetition factor in the first RACH attempt.

[0333] - Option 1-4: The UE prioritizes SSB / CSI-RS with RSRP corresponding to a repetition factor less than or equal to the repetition factor of the first RACH attempt, then prioritizes SSB / CSI-RS with RSRP corresponding to a repetition factor greater than the repetition factor of the first RACH attempt.

[0334] <<<<Specific Examples of Each Choice>>> In the following specific examples, as in the example of FIG. 11 , the existing thresholds rsrp-ThresholdSSB / rsrp-ThresholdCSI-RS, a higher threshold RSRP_thr2, a higher threshold RSRP_thr1, and a higher threshold RSRP_thr0 may be set / defined. Whether a single PRACH transmission or multiple PRACH transmission is performed in the first RACH attempt and the repetition factor K for multiple PRACH transmission are associated with the RSRP thresholds. If an SSB / CSI-RS with an RSRP greater than RSRP_thr0 is present in the first RACH attempt, single PRACH transmission may be selected. If no SSB / CSI-RS with an RSRP greater than RSRP_thr0 is present in the first RACH attempt, multiple PRACH transmission may be selected. If there is an SSB / CSI-RS with an RSRP that does not exceed RSRP_thr0 but exceeds RSRP_thr1 in the first RACH attempt, K=2 is determined. If there is an SSB / CSI-RS with an RSRP that does not exceed RSRP_thr1 but exceeds RSRP_thr2 in the first RACH attempt, K=4 is determined. If there is no SSB / CSI-RS with an RSRP that exceeds RSRP_thr2 in the first RACH attempt, K=8 is determined.

[0335] Example: K=2, option 1-1, the UE may follow the following actions:

[0336] 12, an SSB / CSI-RS having an RSRP greater than RSRP_thr0 may be identified as SSB / CSI-RS Set #0. An SSB / CSI-RS having an RSRP not greater than RSRP_thr0 but greater than RSRP_thr1 may be identified as SSB / CSI-RS Set #1. An SSB / CSI-RS having an RSRP not greater than RSRP_thr1 but greater than RSRP_thr2 may be identified as SSB / CSI-RS Set #2. An SSB / CSI-RS having an RSRP not greater than RSRP_thr2 but greater than rsrp-ThresholdSSB / rsrp-ThresholdCSI-RS may be identified as SSB / CSI-RS Set #3. SSB / CSI-RS with RSRP not exceeding rsrp-ThresholdSSB / rsrp-ThresholdCSI-RS may be identified as SSB / CSI-RS Set #4.

[0337] -- If the repetition factor K=2 in the first RACH attempt, the priority of the SSB / CSI-RS sets selected in SSB / CSI-RS selection is SSB / CSI-RS Sets #1, #0, #2, #3, and #4. If there is an SSB / CSI-RS in SSB / CSI-RS Set #1, the UE selects that SSB / CSI-RS. If there is no SSB / CSI-RS in SSB / CSI-RS Set #1 and there is an SSB / CSI-RS in SSB / CSI-RS Set #0, the UE selects that SSB / CSI-RS. If there is no SSB / CSI-RS in SSB / CSI-RS Sets #1 and #0, and if there is an SSB / CSI-RS in SSB / CSI-RS Set #2, the UE selects that SSB / CSI-RS. If there is no SSB / CSI-RS in SSB / CSI-RS Sets #1, #0, and #2, and if there is an SSB / CSI-RS in SSB / CSI-RS Set #3, the UE selects that SSB / CSI-RS. If there is no SSB / CSI-RS in SSB / CSI-RS Sets #1, #0, #2, and #3, the UE selects any SSB / CSI-RS.

[0338] Example: K=2, option 1-2, the UE may follow the following actions:

[0339] 13, an SSB / CSI-RS having an RSRP greater than RSRP_thr1 may be identified as SSB / CSI-RS Set #0. An SSB / CSI-RS having an RSRP not greater than RSRP_thr1 but greater than RSRP_thr2 may be identified as SSB / CSI-RS Set #1. An SSB / CSI-RS having an RSRP not greater than RSRP_thr2 but greater than rsrp-ThresholdSSB / rsrp-ThresholdCSI-RS may be identified as SSB / CSI-RS Set #2. An SSB / CSI-RS having an RSRP not greater than rsrp-ThresholdSSB / rsrp-ThresholdCSI-RS may be identified as SSB / CSI-RS Set #3.

[0340] -- If the repetition factor K=2 in the first RACH attempt, the priority of the SSB / CSI-RS sets selected in SSB / CSI-RS selection is SSB / CSI-RS Set #0, #1, #2, #3. If there is an SSB / CSI-RS in SSB / CSI-RS Set #0, the UE selects that SSB / CSI-RS. If there is no SSB / CSI-RS in SSB / CSI-RS Set #0 and there is an SSB / CSI-RS in SSB / CSI-RS Set #1, the UE selects that SSB / CSI-RS. If there is no SSB / CSI-RS in SSB / CSI-RS Sets #0 and #1, and there is an SSB / CSI-RS in SSB / CSI-RS Set #2, the UE selects that SSB / CSI-RS. If there is no SSB / CSI-RS in SSB / CSI-RS Sets #0, #1, and #2, the UE selects any SSB / CSI-RS.

[0341] Example: K=2, options 1-3, the UE may follow the following behavior:

[0342] 14, an SSB / CSI-RS having an RSRP greater than RSRP_thr0 may be identified as SSB / CSI-RS Set #0. An SSB / CSI-RS having an RSRP not greater than RSRP_thr0 but greater than RSRP_thr1 may be identified as SSB / CSI-RS Set #1. An SSB / CSI-RS having an RSRP not greater than RSRP_thr1 but greater than rsrp-ThresholdSSB / rsrp-ThresholdCSI-RS may be identified as SSB / CSI-RS Set #2. An SSB / CSI-RS having an RSRP not greater than rsrp-ThresholdSSB / rsrp-ThresholdCSI-RS may be identified as SSB / CSI-RS Set #3.

[0343] -- If the repetition factor K=2 in the first RACH attempt, the priority of the SSB / CSI-RS sets selected in SSB / CSI-RS selection is SSB / CSI-RS Set #1, #0, #2, #3. If there is an SSB / CSI-RS in SSB / CSI-RS Set #1, the UE selects that SSB / CSI-RS. If there is no SSB / CSI-RS in SSB / CSI-RS Set #1 and there is an SSB / CSI-RS in SSB / CSI-RS Set #0, the UE selects that SSB / CSI-RS. If there is no SSB / CSI-RS in SSB / CSI-RS Sets #1 and #0, and there is an SSB / CSI-RS in SSB / CSI-RS Set #2, the UE selects that SSB / CSI-RS. If there is no SSB / CSI-RS in SSB / CSI-RS Sets #1, #0, and #2, the UE selects any SSB / CSI-RS.

[0344] Example: K=2, options 1-4, the UE may follow the following actions:

[0345] 15, an SSB / CSI-RS having an RSRP exceeding RSRP_thr1 may be identified as SSB / CSI-RS Set #0. An SSB / CSI-RS having an RSRP not exceeding RSRP_thr1 but exceeding rsrp-ThresholdSSB / rsrp-ThresholdCSI-RS may be identified as SSB / CSI-RS Set #1. An SSB / CSI-RS having an RSRP not exceeding rsrp-ThresholdSSB / rsrp-ThresholdCSI-RS may be identified as SSB / CSI-RS Set #2.

[0346] -- If the repetition factor K=2 in the first RACH attempt, the priority of the SSB / CSI-RS sets selected in SSB / CSI-RS selection is SSB / CSI-RS Set #0, #1, #2. If there is an SSB / CSI-RS in SSB / CSI-RS Set #0, the UE selects that SSB / CSI-RS. If there is no SSB / CSI-RS in SSB / CSI-RS Set #0 and if there is an SSB / CSI-RS in SSB / CSI-RS Set #1, the UE selects that SSB / CSI-RS. If there is no SSB / CSI-RS in SSB / CSI-RS Set #0 or #1, the UE selects any SSB / CSI-RS.

[0347] Example: K=4, option 1-1, the UE may follow the following behavior:

[0348] 16, an SSB / CSI-RS having an RSRP greater than RSRP_thr0 may be identified as SSB / CSI-RS Set #0. An SSB / CSI-RS having an RSRP not greater than RSRP_thr0 but greater than RSRP_thr1 may be identified as SSB / CSI-RS Set #1. An SSB / CSI-RS having an RSRP not greater than RSRP_thr1 but greater than RSRP_thr2 may be identified as SSB / CSI-RS Set #2. An SSB / CSI-RS having an RSRP not greater than RSRP_thr2 but greater than rsrp-ThresholdSSB / rsrp-ThresholdCSI-RS may be identified as SSB / CSI-RS Set #3. SSB / CSI-RS with RSRP not exceeding rsrp-ThresholdSSB / rsrp-ThresholdCSI-RS may be identified as SSB / CSI-RS Set #4.

[0349] -- If the repetition factor K=4 in the first RACH attempt, the priority of the SSB / CSI-RS sets selected in SSB / CSI-RS selection is SSB / CSI-RS Set #2, #1, #0, #3, #4. If there is an SSB / CSI-RS in SSB / CSI-RS Set #2, the UE selects that SSB / CSI-RS. If there is no SSB / CSI-RS in SSB / CSI-RS Set #2 and there is an SSB / CSI-RS in SSB / CSI-RS Set #1, the UE selects that SSB / CSI-RS. If there is no SSB / CSI-RS in SSB / CSI-RS Sets #2 and #1 and there is an SSB / CSI-RS in SSB / CSI-RS Set #0, the UE selects that SSB / CSI-RS. If there is no SSB / CSI-RS in SSB / CSI-RS Sets #2, #1, and #0 and there is an SSB / CSI-RS in SSB / CSI-RS Set #3, the UE selects that SSB / CSI-RS. If there is no SSB / CSI-RS in SSB / CSI-RS Sets #2, #1, #0, and #3, the UE selects any SSB / CSI-RS.

[0350] Example: K=4, option 1-2, the UE may follow the following behavior:

[0351] 17, an SSB / CSI-RS having an RSRP exceeding RSRP_thr2 may be identified as SSB / CSI-RS Set #0. An SSB / CSI-RS having an RSRP not exceeding RSRP_thr2 but exceeding rsrp-ThresholdSSB / rsrp-ThresholdCSI-RS may be identified as SSB / CSI-RS Set #1. An SSB / CSI-RS having an RSRP not exceeding rsrp-ThresholdSSB / rsrp-ThresholdCSI-RS may be identified as SSB / CSI-RS Set #2.

[0352] -- If the repetition factor K=4 in the first RACH attempt, the priority of the SSB / CSI-RS sets selected in SSB / CSI-RS selection is SSB / CSI-RS Set #0, #1, #2. If there is an SSB / CSI-RS in SSB / CSI-RS Set #0, the UE selects that SSB / CSI-RS. If there is no SSB / CSI-RS in SSB / CSI-RS Set #0 and if there is an SSB / CSI-RS in SSB / CSI-RS Set #1, the UE selects that SSB / CSI-RS. If there is no SSB / CSI-RS in SSB / CSI-RS Set #0 or #1, the UE selects any SSB / CSI-RS.

[0353] Example: K=4, options 1-3, the UE may follow the following behavior:

[0354] 16, an SSB / CSI-RS having an RSRP greater than RSRP_thr0 may be identified as SSB / CSI-RS Set #0. An SSB / CSI-RS having an RSRP not greater than RSRP_thr0 but greater than RSRP_thr1 may be identified as SSB / CSI-RS Set #1. An SSB / CSI-RS having an RSRP not greater than RSRP_thr1 but greater than RSRP_thr2 may be identified as SSB / CSI-RS Set #2. An SSB / CSI-RS having an RSRP not greater than RSRP_thr2 but greater than rsrp-ThresholdSSB / rsrp-ThresholdCSI-RS may be identified as SSB / CSI-RS Set #3. SSB / CSI-RS with RSRP not exceeding rsrp-ThresholdSSB / rsrp-ThresholdCSI-RS may be identified as SSB / CSI-RS Set #4.

[0355] -- If the repetition factor K=4 in the first RACH attempt, the priority of the SSB / CSI-RS sets selected in SSB / CSI-RS selection is SSB / CSI-RS Set #2, #1, #0, #3, #4. If there is an SSB / CSI-RS in SSB / CSI-RS Set #2, the UE selects that SSB / CSI-RS. If there is no SSB / CSI-RS in SSB / CSI-RS Set #2 and there is an SSB / CSI-RS in SSB / CSI-RS Set #1, the UE selects that SSB / CSI-RS. If there is no SSB / CSI-RS in SSB / CSI-RS Sets #2 and #1 and there is an SSB / CSI-RS in SSB / CSI-RS Set #0, the UE selects that SSB / CSI-RS. If there is no SSB / CSI-RS in SSB / CSI-RS Sets #2, #1, and #0 and there is an SSB / CSI-RS in SSB / CSI-RS Set #3, the UE selects that SSB / CSI-RS. If there is no SSB / CSI-RS in SSB / CSI-RS Sets #2, #1, #0, and #3, the UE selects any SSB / CSI-RS.

[0356] Example: K=4, options 1-4, the UE may follow the following behavior:

[0357] 17, an SSB / CSI-RS having an RSRP exceeding RSRP_thr2 may be identified as SSB / CSI-RS Set #0. An SSB / CSI-RS having an RSRP not exceeding RSRP_thr2 but exceeding rsrp-ThresholdSSB / rsrp-ThresholdCSI-RS may be identified as SSB / CSI-RS Set #1. An SSB / CSI-RS having an RSRP not exceeding rsrp-ThresholdSSB / rsrp-ThresholdCSI-RS may be identified as SSB / CSI-RS Set #2.

[0358] -- If the repetition factor K=4 in the first RACH attempt, the priority of the SSB / CSI-RS sets selected in SSB / CSI-RS selection is SSB / CSI-RS Set #0, #1, #2. If there is an SSB / CSI-RS in SSB / CSI-RS Set #0, the UE selects that SSB / CSI-RS. If there is no SSB / CSI-RS in SSB / CSI-RS Set #0 and if there is an SSB / CSI-RS in SSB / CSI-RS Set #1, the UE selects that SSB / CSI-RS. If there is no SSB / CSI-RS in SSB / CSI-RS Set #0 or #1, the UE selects any SSB / CSI-RS.

[0359] <<Embodiment 2-2>> Power ramping in RACH retry in this case may follow at least one of the following options: - Option 1: If the selected SSB / CSI-RS has not changed from the selection in the last RACH attempt, the UE increments PREAMBLE_POWER_RAMPING_COUNTER by 1. If the selected SSB / CSI-RS has changed from the selection in the last RACH attempt, the UE maintains PREAMBLE_POWER_RAMPING_COUNTER.

[0360] - Option 2: An extended power ramping rule is applied based on the RSRP threshold for determining the number of PRACH transmissions and the RSRP of the selected SSB / CSI-RS. As in embodiment 2-1, the repetition factor corresponding to the RSRP may be determined based on the threshold. The UE may follow at least one of the following rules:

[0361] -- Rule 1: If the RSRP of the selected SSB / CSI-RS corresponds to a repetition factor greater than the repetition factor in the last RACH attempt, the UE may follow at least one of the following actions: -- If the selected SSB / CSI-RS has not changed from the selection in the last RACH attempt, the UE may increment the PREAMBLE_POWER_RAMPING_COUNTER by X, where X may be equal to or greater than 1. X may be defined by the specification or may be indicated / configured by the base station. -- If the selected SSB / CSI-RS has changed from the selection in the last RACH attempt, the UE may increment the PREAMBLE_POWER_RAMPING_COUNTER by Y, where Y may be equal to or greater than 0. Y may be defined by the specification or may be indicated / configured by the base station. --- Variation: The values ​​of X and Y may depend on the gap between the determined repetition factor and the repetition factor corresponding to the selected SSB / CSI-RS (the values ​​of X and Y may be different for different values ​​of the gap).

[0362] -- Rule 2: If the RSRP of the selected SSB / CSI-RS corresponds to a repetition factor smaller than the repetition factor in the last RACH attempt, the UE may follow some of the following actions: -- If the selected SSB / CSI-RS has not changed from the selection in the last RACH attempt, the UE may increment the PREAMBLE_POWER_RAMPING_COUNTER by X, where X may be equal to 0 or 1 or greater than 0 or 1. X may be defined by the specification or may be indicated / configured by the base station. -- If the selected SSB / CSI-RS has changed from the selection in the last RACH attempt, the UE may increment the PREAMBLE_POWER_RAMPING_COUNTER by Y, where Y may be equal to 0 or greater than 0. Y may be defined by the specification or may be indicated / configured by the base station. --- Variation: The values ​​of X and Y may depend on the gap between the determined repetition factor and the repetition factor corresponding to the selected SSB / CSI-RS (the values ​​of X and Y may be different for different values ​​of the gap).

[0363] Separate power ramping step sizes may be set / indicated for different repetition factors. In an RA procedure using a specific repetition factor, a power ramping step size for that specific repetition factor may be applied. For example, for RA procedures using repetition factors of 2, 4, and 8, the RRC IEs powerRampingStep-Rep2, powerRampingStep-Rep4, and powerRampingStep-Rep8 may be set / indicated, respectively. If the repetition factor for an RA procedure is 2, powerRampingStep-Rep2 may be applied to that RA procedure.

[0364] <<Embodiment 2-3>> The maximum value of the preamble transmission counter in this case (maximum number of random access preamble transmissions) may be set / instructed as follows.

[0365] The maximum number of random access preamble transmissions (preambleTransMax) can be configured / indicated separately for different repetition factors. In a certain RA procedure, a maximum number (limit) of random access preamble transmissions corresponding to the repetition factor for that RA procedure may be applied. For example, the RRC IEs preambleTransMax-Rep2, preambleTransMax-Rep4, and preambleTransMax-Rep8 may be configured / indicated for RA procedures using repetition factors of 2, 4, and 8, respectively. If the repetition factor for an RA procedure is 2, preambleTransMax-Rep2 may be applied to that RA procedure.

[0366] According to this embodiment, if multiple PRACH transmissions are decided for the first RACH attempt and the number of PRACH transmissions is maintained in RACH retries, the UE can appropriately perform SSB / CSI-RS selection, power ramping and / or preamble transmission counter for one or more RACH attempts within that RA procedure.

[0367] Third Embodiment This embodiment relates to a case where the number of PRACH transmissions is not maintained in RACH retry attempts when multiple PRACH transmissions have been determined.

[0368] If multiple PRACH transmissions are determined for the first RACH attempt, a single PRACH transmission may be applied for one or more RACH attempts within the RAC procedure, and the specification may specify that the number of PRACH transmissions in the RACH retry attempts may be the same as or different from the number of PRACH transmissions in the first RACH attempt.

[0369] If multiple PRACH transmissions are determined for the first RACH attempt, a single PRACH transmission may be applied to one or more RACH attempts within the RAC procedure, and the specification may specify that the number of PRACH transmissions in the RACH retry attempt is the same as the first RACH attempt, or is greater than the number of PRACH transmissions in the first RACH attempt, or is less than the number of PRACH transmissions in the first RACH attempt.

[0370] The operation in this case may follow at least one of several embodiments 3-x below.

[0371] <<Embodiment 3-1>> In this case, the SSB / CSI-RS selection in the RACH retry may follow at least one of the following options: - Option 1-0: Same as in embodiment 2-1. - Option 1-1: Same as in embodiment 2-1. - Option 1-2: Same as in embodiment 2-1. - Option 1-3: Same as in embodiment 2-1. - Option 1-4: Same as in embodiment 2-1. - Option 1-5: The UE prioritizes SSB / CSI-RS with RSRP corresponding to multiple PRACH transmissions, followed by SSB / CSI-RS with RSRP corresponding to a single PRACH transmission.

[0372] <<<Specific Example>>> In the following specific example, similar to the specific examples of each option in embodiment 2-1, the existing thresholds rsrp-ThresholdSSB / rsrp-ThresholdCSI-RS, a higher threshold RSRP_thr2, a higher threshold RSRP_thr1, and a higher threshold RSRP_thr0 may be set / defined.

[0373] Example: K>1, options 1-5, the UE may follow the following actions:

[0374] 18, an SSB / CSI-RS having an RSRP exceeding RSRP_thr0 may be identified as SSB / CSI-RS Set #0. An SSB / CSI-RS having an RSRP not exceeding RSRP_thr0 but exceeding rsrp-ThresholdSSB / rsrp-ThresholdCSI-RS may be identified as SSB / CSI-RS Set #1. An SSB / CSI-RS having an RSRP not exceeding rsrp-ThresholdSSB / rsrp-ThresholdCSI-RS may be identified as SSB / CSI-RS Set #2.

[0375] -- If the repetition factor K>1 in the first RACH attempt, the priority of the SSB / CSI-RS sets selected in SSB / CSI-RS selection is SSB / CSI-RS Set #1, #0, #2. If there is an SSB / CSI-RS in SSB / CSI-RS Set #1, the UE selects that SSB / CSI-RS. If there is no SSB / CSI-RS in SSB / CSI-RS Set #1 and if there is an SSB / CSI-RS in SSB / CSI-RS Set #0, the UE selects that SSB / CSI-RS. If there is no SSB / CSI-RS in SSB / CSI-RS Set #1 or #0, the UE selects any SSB / CSI-RS.

[0376] <<Embodiment 3-2>> Power ramping in RACH retry in this case may follow at least one of the following options.

[0377] - Option 1: If the selected SSB / CSI-RS has not changed from the selection in the last RACH attempt, the UE increments the PREAMBLE_POWER_RAMPING_COUNTER by 1. If the selected SSB / CSI-RS has changed from the selection in the last RACH attempt, the UE maintains the PREAMBLE_POWER_RAMPING_COUNTER.

[0378] - Option 2: Whether power ramping is performed depends on whether repetition factor ramping (changing / increasing the repetition factor) is performed or not. The UE may follow at least one of several rules:

[0379] -- Rule 1: If the determined repetition factor is greater than the repetition factor in the last RACH attempt, the UE may maintain the PREAMBLE_POWER_RAMPING_COUNTER for the SSB / CSI-RS selection in the last RACH attempt, regardless of whether the selected SSB / CSI-RS is the same or different.

[0380] Rule 2: If the determined repetition factor is smaller than the repetition factor in the last RACH attempt, the UE may increment the PREAMBLE_POWER_RAMPING_COUNTER by X, where the value of X may be different for the cases where the selected SSB / CSI-RS is the same as and different from the SSB / CSI-RS selection in the last RACH attempt.

[0381] -- Rule 3: If the determined repetition factor is the same as the repetition factor in the last RACH attempt, the UE may follow at least one of the following actions: -- If the selected SSB / CSI-RS has not changed from the selection in the last RACH attempt, the UE increments the PREAMBLE_POWER_RAMPING_COUNTER by 1. -- If the selected SSB / CSI-RS has changed from the selection in the last RACH attempt, the UE maintains the PREAMBLE_POWER_RAMPING_COUNTER.

[0382] - Variation: Separate power ramping step sizes may be configured / indicated for multiple PRACH transmissions and single PRACH transmissions. The power ramping step size configured / indicated for multiple PRACH transmissions may be applied to an RA procedure using multiple PRACH transmissions (an RA procedure in which multiple PRACH transmissions are determined in the first RACH attempt within the RA procedure). For example, the RRC IE powerRampingStep-MultiPRACH (separate from the RRC IE for an RA procedure using single PRACH transmissions) may be configured / indicated for an RA procedure using multiple PRACH transmissions. If multiple PRACH transmissions are determined in an RA procedure (in the first RACH attempt within the RA procedure), powerRampingStep-MultiPRACH may be applied to the RA procedure.

[0383] <<Embodiment 3-3>> The maximum value of the preamble transmission counter in this case (maximum number of random access preamble transmissions) may follow the following settings / instructions.

[0384] The maximum number of random access preamble transmissions (preambleTransMax) can be configured / indicated separately for multiple PRACH transmissions and single PRACH transmissions. The maximum number (limit) of random access preamble transmissions configured / indicated for multiple PRACH transmissions may be applied to an RA procedure using multiple PRACH transmissions (an RA procedure in which multiple PRACH transmissions are determined in the first RACH attempt within the RA procedure). For example, an RRC IE preambleTransMax-MultiPRACH (separate from the RRC IE for an RA procedure using a single PRACH transmission) may be configured / indicated for an RA procedure using multiple PRACH transmissions. If multiple PRACH transmissions are determined in an RA procedure (in the first RACH attempt within the RA procedure), preambleTransMax-MultiPRACH may be applied to the RA procedure.

[0385] According to this embodiment, if multiple PRACH transmissions are decided for the first RACH attempt and the number of PRACH transmissions is not necessarily maintained for RACH retries, the UE may appropriately perform SSB / CSI-RS selection, power ramping, and / or preamble transmission counter for one or more RACH attempts within the RA procedure.

[0386] <Supplementary Information> [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.

[0387] 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.

[0388] 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.

[0389] Furthermore, notification of any information to the UE in the above embodiments may be performed periodically, semi-persistently, or aperiodically.

[0390] [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.

[0391] 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.

[0392] If the notification is made by UCI, the notification may be transmitted using PUCCH or PUSCH.

[0393] Furthermore, any information in the above-described embodiments may be notified from the UE periodically, semi-persistently, or aperiodically.

[0394] [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.

[0395] At least one of the above-described embodiments may be applied to at least one of the following random access (RA) types, or may be limited to only at least one of the following RA types: CBRA, CFRA, RA ordered on PDCCH, RA for system information acquisition (SI acquisition).

[0396] At least one of the above-described embodiments may be applied only to UEs that have reported or support a particular UE capability.

[0397] The specific UE capabilities may indicate at least one of the following: Supporting specific processing / operations / control / information for at least one of the above embodiments; Supporting changing (increasing / decreasing) the number of PRACH transmissions within one RA procedure; Supporting SSB / CSI-RS selection that takes into account the indicated / configured RSRP threshold for determining the number of PRACH transmissions; Supporting separate power ramping step sizes for RA procedures with different numbers of PRACH transmissions within one RACH attempt; Supporting separate power ramping step sizes for RA procedures with multiple PRACH transmissions within each RACH attempt and for RA procedures with a single PRACH transmission within each RACH attempt; Supporting separate maximum preamble transmission counter numbers for RA procedures with different numbers of PRACH transmissions within one RACH attempt. Supporting separate maximum preamble transmission counter numbers for RA procedures with multiple PRACH transmissions within each RACH attempt and for RA procedures with a single PRACH transmission within each RACH attempt.

[0398] 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).

[0399] 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)).

[0400] Furthermore, at least one of the above-described embodiments may be applied when the UE configures / activates / triggers specific information related to the above-described embodiments (or performs the operations of the above-described embodiments) through higher layer signaling / physical layer signaling. For example, the specific information may be information indicating that at least one of the operations of the above-described embodiments is enabled, any RRC parameter for a specific release (e.g., Rel. 18 / 19), etc.

[0401] In Rel. YY (e.g., YY is 18 or greater), the RRC parameters that enable operation XXX may be represented as XXX_rYY (XXX-rYY).

[0402] 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.

[0403] (Supplementary Notes) The following inventions are supplementary notes regarding one embodiment of the present disclosure. [Supplementary Note 1] A terminal comprising: a receiver that receives one or more first reference signals; and a controller that determines, based on received power of the one or more first reference signals, at least one of whether to perform single random access channel transmission or multiple random channel transmission in an attempt of random access channel transmission and the number of random access channel transmissions in the attempt, and, if the attempt fails, selects a third reference signal for determining resources for a retry based on received power of one or more second reference signals and the determination. [Supplementary Note 2] The terminal according to Supplementary Note 1, wherein, if it is determined to perform single random access channel transmission in the attempt and the attempt fails, the controller determines to perform single random access channel transmission in the retry, and selects the third reference signal from the one or more second reference signals, giving priority to reference signals in a received power range corresponding to the single random access channel transmission. [Supplementary Note 3] The terminal according to Supplementary Note 1 or Supplementary Note 2, wherein, when it is determined to perform multiple random access channel transmissions in the attempt and the attempt fails, the control unit determines to perform multiple random access channel transmissions in the retry, a number of which is equal to the number of random access channel transmissions in the attempt, and selects the third reference signal by giving priority to a reference signal in a received power range corresponding to the number of random access channel transmissions in the attempt or a reference signal in a received power range corresponding to a number equal to or less than the number of random access channel transmissions in the attempt. [Supplementary Note 4] The terminal according to any of Supplementary Note 1 to Supplementary Note 3, wherein, when it is determined to perform multiple random access channel transmissions in the attempt and the attempt fails, the control unit determines to perform multiple random access channel transmissions in the retry and the number of random access channel transmissions in the retry, and selects the third reference signal by giving priority to a reference signal in a received power range corresponding to the number of random access channel transmissions in the attempt or a reference signal in a received power range corresponding to a number equal to or less than the number of random access channel transmissions in the attempt.

[0404] (Supplementary Notes) The following inventions are supplemented with respect to one embodiment of the present disclosure. [Supplementary Note 1] A terminal comprising: a receiver that receives one or more first reference signals; and a controller that determines, based on received power of the one or more first reference signals, at least one of whether to perform a single random access channel transmission or multiple random access channel transmissions in an attempt of random access channel transmission and the number of random access channel transmissions in the attempt, and, if the attempt fails, determines, based on the determination, at least one of a transmission power for a retry attempt and a maximum number of random access channel transmissions. [Supplementary Note 2] The terminal according to Supplementary Note 1, wherein, if it is determined to perform a single random access channel transmission in the attempt and the attempt fails, the controller determines to perform a single random access channel transmission in the retry attempt, selects a third reference signal for determining resources for the retry attempt based on received power of the one or more second reference signals, and determines the transmission power for the retry attempt based on a received power threshold for determining the number of random access channel transmissions, the received power of the third reference signal, and the transmission power for the attempt. [Supplementary Note 3] The terminal according to Supplementary Note 1 or Supplementary Note 2, wherein, when it is determined to perform multiple random access channel transmissions in the attempt and the attempt fails, the controller determines to perform, in the retry, multiple random access channel transmissions, a number of which is equal to the number of random access channel transmissions in the attempt, selects a third reference signal for determining resources for the retry based on received powers of the one or more second reference signals, and determines transmission power for the retry based on a received power threshold for determining the number of random access channel transmissions, the received power of the third reference signal, and a transmission power for the attempt. [Supplementary Note 4] The terminal according to any of Supplementary Note 1 to Supplementary Note 3, wherein, when it is determined to perform multiple random access channel transmissions in the attempt and the attempt fails, the controller determines to perform multiple random access channel transmissions in the retry and the number of random access channel transmissions in the retry, and determines the transmission power for the retry based on the number of random access channel transmissions in the retry and the transmission power for the attempt.

[0405] (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.

[0406] 19 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).

[0407] 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.

[0408] 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.

[0409] 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))).

[0410] 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.

[0411] 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).

[0412] 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.

[0413] 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.

[0414] 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.

[0415] 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.

[0416] 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.

[0417] The user terminal 20 may be a terminal that supports at least one of communication methods such as LTE, LTE-A, and 5G.

[0418] 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).

[0419] 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.

[0420] 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.

[0421] 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.

[0422] 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).

[0423] 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.

[0424] 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.

[0425] 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.

[0426] 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.

[0427] 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.

[0428] 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.

[0429] 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.

[0430] 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.

[0431] 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).

[0432] (Base Station) Fig. 20 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.

[0433] 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.

[0434] 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.

[0435] 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.

[0436] 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.

[0437] 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.

[0438] 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.

[0439] 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.

[0440] 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.

[0441] 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.

[0442] 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.

[0443] 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.

[0444] 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.

[0445] 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.

[0446] 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.

[0447] 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.

[0448] 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.

[0449] The transceiver 120 may transmit one or more first reference signals. The controller 110 may control retry reception when an attempt to transmit a random access channel fails. At least one of whether to perform a single random access channel transmission or multiple random channel transmissions in the attempt and the number of random access channel transmissions in the attempt may be determined based on the received power of the one or more first reference signals. When the attempt fails, a third reference signal for determining resources for the retry may be selected based on the received power of one or more second reference signals and the determination.

[0450] The transceiver 120 may transmit one or more first reference signals. The controller 110 may control retry reception if an attempt to transmit a random access channel fails. At least one of whether to perform a single random access channel transmission or multiple random access channel transmissions in the attempt and the number of random access channel transmissions in the attempt may be determined based on the received power of the one or more first reference signals. If the attempt fails, at least one of the transmission power of the retry and the maximum number of random access channel transmissions may be determined based on the determination.

[0451] (User Terminal) Fig. 21 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.

[0452] 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.

[0453] 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.

[0454] 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.

[0455] 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.

[0456] 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.

[0457] 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.

[0458] 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.

[0459] 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.

[0460] 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.

[0461] 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.

[0462] 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.

[0463] 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.

[0464] 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.

[0465] 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.

[0466] 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.

[0467] The measurement unit 223 may derive channel measurements for CSI calculation based on the channel measurement resources. The channel measurement resources may be, for example, non-zero power (NZP) CSI-RS resources. The measurement unit 223 may also derive interference measurements for CSI calculation based on the interference measurement resources. The interference measurement resources may be at least one of an NZP CSI-RS resource for interference measurement, a CSI-Interference Measurement (IM) resource, etc. Note that CSI-IM may be referred to as CSI-Interference Management (IM) or may be interchangeably read as Zero Power (ZP) CSI-RS. Note that in the present disclosure, CSI-RS, NZP CSI-RS, ZP CSI-RS, CSI-IM, CSI-SSB, etc. may be interchangeably read as interchangeable.

[0468] 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.

[0469] The transceiver unit 220 may receive one or more first reference signals (e.g., one or more SSB / CSI-RS for determining resources for the initial RACH attempt). The controller 210 may determine at least one of whether to perform a single random access channel transmission or multiple random channel transmissions in a random access channel transmission attempt (e.g., an initial RACH attempt) and the number of random access channel transmissions in the attempt based on the received power (e.g., RSRP) of the one or more first reference signals. If the attempt fails, the controller 210 may select a third reference signal (e.g., SSB / CSI-RS for determining resources for the RACH retry) for determining resources for the retry based on the received power of one or more second reference signals (e.g., one or more SSB / CSI-RS for determining resources for the RACH retry) and the determination.

[0470] If it is determined that a single random access channel transmission is to be performed in the attempt and the attempt fails, the control unit 210 may determine that a single random access channel transmission is to be performed in the retry, and may select the third reference signal from the one or more second reference signals by prioritizing reference signals that are in a received power range corresponding to the single random access channel transmission (e.g., whether or not a specific RSRP threshold is exceeded, SSB / CSI-RS set).

[0471] If it is determined that multiple random access channel transmissions will be performed in the attempt and the attempt fails, the control unit 210 may determine that multiple random access channel transmissions will be performed in the retry attempt, the number of which is equal to the number of random access channel transmissions in the attempt, and may select the third reference signal by giving priority to a reference signal that is within a received power range corresponding to the number of random access channel transmissions in the attempt, or a reference signal that is within a received power range corresponding to a number equal to or less than the number of random access channel transmissions in the attempt.

[0472] If it is determined that multiple random access channel transmissions will be performed in the attempt and the attempt fails, the control unit 210 may determine that multiple random access channel transmissions will be performed in the retry attempt and the number of random access channel transmissions in the retry attempt, and may select the third reference signal by giving priority to a reference signal that is within a reception power range corresponding to the number of random access channel transmissions in the attempt, or a reference signal that is within a reception power range corresponding to a number equal to or less than the number of random access channel transmissions in the attempt.

[0473] The transceiver unit 220 may receive one or more first reference signals. The control unit 210 may determine, based on the received power of the one or more first reference signals, at least one of whether to perform a single random access channel transmission or multiple random access channel transmissions in a random access channel transmission attempt and the number of random access channel transmissions in the attempt, and, if the attempt fails, may determine, based on the determination, at least one of a transmission power for a retry (e.g., power ramping) and a maximum number of random access channel transmissions.

[0474] If it is determined to perform a single random access channel transmission in the attempt and the attempt fails, the control unit 210 may determine to perform a single random access channel transmission in the retry, select a third reference signal for determining resources for the retry based on the received power of the one or more second reference signals, and determine the transmission power for the retry based on a received power threshold for determining the number of random access channel transmissions, the received power of the third reference signal, and the transmission power of the attempt.

[0475] If it is determined that multiple random access channel transmissions will be performed in the attempt and the attempt fails, the control unit 210 may determine that multiple random access channel transmissions will be performed in the retry, the number of which is equal to the number of random access channel transmissions in the attempt, select a third reference signal for determining resources for the retry based on received power of the one or more second reference signals, and determine the transmission power for the retry based on a received power threshold for determining the number of random access channel transmissions, the received power of the third reference signal, and the transmission power of the attempt.

[0476] If it is determined that multiple random access channel transmissions will be performed in the attempt and the attempt fails, the control unit 210 may determine that multiple random access channel transmissions will be performed in the retry attempt and the number of random access channel transmissions in the retry attempt, and may determine the transmission power for the retry attempt based on the number of random access channel transmissions in the retry attempt and the transmission power for the attempt.

[0477] (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.

[0478] 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.

[0479] 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. 22 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.

[0480] 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.

[0481] 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.

[0482] 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.

[0483] 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.

[0484] 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.

[0485] 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.

[0486] 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.

[0487] 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.

[0488] 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).

[0489] 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.

[0490] 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.

[0491] (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.

[0492] 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.

[0493] 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.

[0494] 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.

[0495] 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.

[0496] 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.

[0497] 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.

[0498] 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.

[0499] 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.

[0500] 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.

[0501] 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.

[0502] 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.

[0503] 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.

[0504] 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.

[0505] 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.

[0506] 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.

[0507] 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.

[0508] 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.

[0509] 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."

[0510] 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.

[0511] 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.

[0512] 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.

[0513] 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.

[0514] 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.

[0515] 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.

[0516] 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.

[0517] 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).

[0518] 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).

[0519] 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).

[0520] 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.

[0521] 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.

[0522] 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).

[0523] In this 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," "layer," "number of layers," "rank," "resource," "resource set," "beam," "beam width," "beam angle," "antenna," "antenna element," "panel," "UE panel," "transmitting entity," "receiving entity," etc. may be used interchangeably.

[0524] In the present disclosure, the term "antenna port" may be interchangeably read as an antenna port for any signal / channel (e.g., a demodulation reference signal (DMRS) port). In the present disclosure, the term "resource" may be interchangeably read as a resource for any signal / channel (e.g., a reference signal resource, an SRS resource, etc.). The resource may include time / frequency / code / space / power resources. Furthermore, the spatial domain transmission filter may include at least one of a spatial domain transmission filter and a spatial domain reception filter.

[0525] The group may include, for example, at least one of a spatial relationship group, a Code Division Multiplexing (CDM) group, a Reference Signal (RS) group, a Control Resource Set (CORESET) group, a PUCCH group, an antenna port group (e.g., a DMRS port group), a layer group, a resource group, a beam group, an antenna group, a panel group, and the like.

[0526] In addition, in the present disclosure, beam, SRS Resource Indicator (SRI), CORESET, CORESET pool, PDSCH, PUSCH, codeword (CW), transport block (TB), RS, etc. may be read as interchangeable terms.

[0527] In addition, in the present disclosure, the terms TCI state, downlink TCI state (DL TCI state), uplink TCI state (UL TCI state), unified TCI state, common TCI state, joint TCI state, etc. may be read interchangeably.

[0528] Furthermore, in the present disclosure, terms such as "QCL," "QCL assumption," "QCL relationship," "QCL type information," "QCL property / properties," "specific QCL type (e.g., Type A, Type D) property," and "specific QCL type (e.g., Type A, Type D)" may be interchangeable.

[0529] In the present disclosure, terms such as index, identifier (ID), indicator, indication, and resource ID may be interchangeable. In the present disclosure, terms such as sequence, list, set, group, cluster, and subset may be interchangeable.

[0530] Furthermore, the spatial relationship information identifier (ID) (TCI state ID) and the spatial relationship information (TCI state) may be interchangeable. The "spatial relationship information (TCI state)" may be interchangeable with "set of spatial relationship information (TCI state)", "one or more pieces of spatial relationship information", etc. The TCI state and the TCI may be interchangeable. The spatial relationship information and the spatial relationship may be interchangeable.

[0531] 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.

[0532] 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.

[0533] 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.

[0534] In this disclosure, the terms "Mobile Station (MS)," "user terminal," "User Equipment (UE)," "terminal," etc. may be used interchangeably.

[0535] 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.

[0536] 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.

[0537] 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.

[0538] 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.

[0539] 23 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.

[0540] 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.

[0541] 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).

[0542] 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.

[0543] 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.

[0544] 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.

[0545] 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.

[0546] 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.

[0547] 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).

[0548] 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.

[0549] 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)).

[0550] 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.

[0551] 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.

[0552] 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.

[0553] 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.

[0554] 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.

[0555] 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).

[0556] 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."

[0557] 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.

[0558] 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.

[0559] 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.

[0560] Furthermore, "determination" may be considered to be "determining" resolving, selecting, choosing, establishing, comparing, etc. In other words, "determination" may be considered to be "determining" some kind of action. In the present disclosure, "determination" may be read interchangeably with the above-mentioned actions.

[0561] Furthermore, in this disclosure, "determine / determining" may be interchangeably read as "assume / assuming," "expect / expecting," "consider / considering," etc. Furthermore, in this disclosure, "does not expect to do..." may be interchangeably read as "assumes not to do...."

[0562] In the present disclosure, "expect" may be interchangeably read as "be expected." For example, "expect(s) ..." ("..." may be expressed, for example, as a that clause, a to-infinitive, etc.) may be interchangeably read as "be expected ...." "does not expect ..." may be interchangeably read as "be not expected ...." Furthermore, "An apparatus A is not expected ..." may be interchangeably read as "an apparatus B other than apparatus A does not expect ... from apparatus A" (e.g., if apparatus A is a UE, apparatus B may be a base station).

[0563] 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.

[0564] 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."

[0565] 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.

[0566] 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."

[0567] 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.

[0568] 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.

[0569] 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").

[0570] In this disclosure, the terms "of," "for," "regarding," "related to," "associated with," etc. may be read interchangeably.

[0571] In the present disclosure, terms such as "when A, B," "if A, (then) B," "B upon A," "B in response to A," "B based on A," "B during / while A," "B before A," "B at (the same time as) / on A," "B after A," "B since A," and "B until A" may be interchangeable. Note that A, B, and the like herein may be replaced with appropriate expressions such as nouns, gerunds, and regular sentences, depending on the context. Note that the time difference between A and B may be approximately zero (immediately after or immediately before). A time offset may also be applied to the time at which A occurs. For example, "A" may be interchangeable with "before / after a time offset at which A occurs." The time offset (eg, one or more symbols / slots) may be predefined or may be specified by the UE based on signaled information.

[0572] In the present disclosure, timing, time, duration, time instance, any time unit (e.g., slot, subslot, symbol, subframe), period, occasion, resource, etc. may be read interchangeably.

[0573] 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 description of the present disclosure is for illustrative purposes only and does not impose any limiting meaning on the invention according to the present disclosure.

Claims

1. A receiving unit that receives a reference signal, The system includes a control unit that, based on the received power of the reference signal, determines whether to apply a single random access preamble transmission in which the random access preamble is not repeatedly transmitted, or a multiple random access preamble transmission in which the random access preamble is repeatedly transmitted, and the number of times the transmission is repeated, in an attempt to transmit the random access preamble in a random access procedure. A terminal in which the maximum number of random access preamble transmissions for a single random access preamble transmission and the maximum number of random access preamble transmissions for multiple random access preamble transmissions are set individually.

2. The terminal according to claim 1, wherein when the control unit decides to apply the multiple random access preamble transmission in the retry of the transmission of the random access preamble in the random access procedure, the maximum number of random access preamble transmissions for the single random access preamble transmission and the maximum number of random access preamble transmissions for the multiple random access preamble transmissions are set individually.

3. The terminal according to claim 2, wherein, when certain conditions are met, the number of times the random access preamble is repeatedly transmitted in the trial is different from the number of times the random access preamble is repeatedly transmitted in the retry.

4. The terminal according to claim 1, wherein the reference signal is a Synchronization Signal Block (SSB) or a Channel State Information Reference Signal (CSI-RS).

5. The steps of receiving a reference signal, The procedure includes the step of determining, based on the received power of the reference signal, whether to apply a single random access preamble transmission in which the random access preamble is not repeatedly transmitted, or a multiple random access preamble transmission in which the random access preamble is repeatedly transmitted, and the number of times the transmission is repeated, in an attempt to transmit the random access preamble in a random access procedure. A wireless communication method for a terminal, wherein the maximum number of random access preamble transmissions for a single random access preamble transmission and the maximum number of random access preamble transmissions for multiple random access preamble transmissions are set individually.

6. A transmitting unit that transmits a reference signal to a terminal, A control unit that individually sets for the terminal the maximum number of random access preamble transmissions for a single random access preamble transmission in which repeated transmissions of the random access preamble are not performed, and the maximum number of random access preamble transmissions for multiple random access preamble transmissions in which repeated transmissions of the random access preamble are performed. A base station having, based on the received power of the reference signal, a receiving unit that receives the transmitted random access preamble, where the application of a single random access preamble transmission or a multiple random access preamble transmission and the number of repeated transmissions are determined in an attempt to transmit a random access preamble in a random access procedure.

7. A system including a terminal and a base station, The aforementioned terminal is A receiving unit that receives a reference signal, The system includes a control unit that, based on the received power of the reference signal, determines whether to apply a single random access preamble transmission in which the random access preamble is not repeatedly transmitted, or a multiple random access preamble transmission in which the random access preamble is repeatedly transmitted, and the number of times the transmission is repeated, in an attempt to transmit the random access preamble in a random access procedure. The maximum number of random access preamble transmissions for a single random access preamble transmission and the maximum number of random access preamble transmissions for multiple random access preamble transmissions are set individually. The aforementioned base station is A transmitting unit that transmits the aforementioned reference signal to the terminal, A control unit that individually sets the maximum number of random access preamble transmissions for a single random access preamble transmission and the maximum number of random access preamble transmissions for multiple random access preamble transmissions for the terminal, A system comprising a receiving unit that receives the aforementioned random access preamble.