Terminal, base station, wireless system, and communication method

Abstract

A terminal according to one aspect of the present disclosure comprises: a control unit that sets a first parameter value used for generating a first root sequence for a first transmission of a random access channel, and a second parameter value differing from the first parameter value or a difference with respect to the first parameter value, to be used for generating a second root sequence for a second transmission of the random access channel; and a transmission unit that transmits the random access channel as the first transmission to a base station on the basis of the first root sequence corresponding to the first parameter value, and transmits the random access channel as the second transmission to the base station on the basis of the second root sequence corresponding to the second parameter value or the difference.

Description

Terminal and communication method

[0001] The present disclosure relates to a terminal and a communication method.

[0002] The 3rd Generation Partnership Project (3GPP) is specifying the 5th generation mobile communication system (5G, also known as New Radio (NR) or Next Generation (NG)), and is also specifying the next generation, called Beyond 5G, 5G Evolution, or 6G.

[0003] In Long Term Evolution (LTE), when uplink (UL) synchronization is established between a base station and a terminal, UL data can be transmitted from the terminal. For this reason, LTE supports a random access procedure for establishing UL synchronization. The random access procedure may also be referred to as a RACH procedure (Random Access Channel Procedure), an access procedure, or the like. On the other hand, NR also specifies a random access procedure similar to that of LTE (for example, Non-Patent Documents 1, 2, and 3).

[0004] Also, for example, in 3GPP Release 18, a work item (WI) on PRACH coverage extension, including multiple transmissions of a physical random access channel (PRACH) using the same beam as a synchronization signal block (SSB), for a four-step random access procedure, has been agreed upon. Note that the PRACH may also be referred to as a random access channel, an uplink channel, an uplink signal, or the like.

[0005] 3GPP TS 38.211 V17.0.0 (2021-12)3GPP TS 38.213 V17.0.0 (2021-12)3GPP TS 38.321 V16.7.0 (2021-12)“Further NR Coverage Enhancement”, RP-213579, 3GPP TSG RAN Meeting #94-e, 3GPP, December 2021

[0006] As described above, in future wireless communication systems, repeated transmission of the PRACH is being considered, but how to control repeated transmission of the PRACH in a random access procedure is an issue. However, specific operations related to repeated transmission of the PRACH have not been fully considered. If repeated transmission of the PRACH is not performed appropriately, there is a risk that communication quality will deteriorate.

[0007] One aspect of the present disclosure provides a terminal and a communication method that can appropriately perform repeated transmission of a PRACH in a random access procedure.

[0008] A terminal according to one aspect of the present disclosure includes: a control unit that sets a first parameter value used to generate a first root sequence for a first transmission of a random access channel; and a second parameter value different from the first parameter value or a difference from the first parameter value, used to generate a second root sequence for a second transmission of the random access channel; and a transmission unit that transmits the random access channel as the first transmission to a base station based on the first root sequence corresponding to the first parameter value, and transmits the random access channel as the second transmission to the base station based on the second root sequence corresponding to the second parameter value or the difference.

[0009] A terminal according to one aspect of the present disclosure includes: a control unit that sets the number of preambles usable per resource for a random access channel to a number greater than 64; and that randomly sets a first preamble for a first transmission of the random access channel from among the usable preambles; and a transmission unit that transmits the random access channel including the first preamble to a base station as the first transmission, and transmits the random access channel including the second preamble to the base station as the second transmission.

[0010] In a communication method according to one aspect of the present disclosure, a terminal sets a first parameter value used to generate a first root sequence for a first transmission of a random access channel and a second parameter value different from the first parameter value or a difference from the first parameter value used to generate a second root sequence for a second transmission of the random access channel, and transmits the random access channel as the first transmission to a base station based on the first root sequence corresponding to the first parameter value, and transmits the random access channel as the second transmission to the base station based on the second root sequence corresponding to the second parameter value or the difference.

[0011] A communication method according to one aspect of the present disclosure includes a terminal setting the number of preambles usable per resource for a random access channel, the number being greater than 64, randomly setting a first preamble for a first transmission of the random access channel from among the usable preambles, randomly setting a second preamble for a second transmission of the random access channel from among the usable preambles, transmitting the random access channel including the first preamble to a base station as the first transmission, and transmitting the random access channel including the second preamble to the base station as the second transmission.

[0012] 7 is a diagram illustrating an example of a wireless communication system according to an embodiment of the present disclosure. FIG. 8 is a diagram illustrating an example of a frequency range used in the wireless communication system according to an embodiment of the present disclosure. FIG. 9 is a diagram illustrating an example of the configuration of a radio frame, a subframe, and a slot used in the wireless communication system according to an embodiment of the present disclosure. FIG. 10 is a sequence diagram illustrating an example of a CBRA procedure. FIG. 11 is a sequence diagram illustrating another example of a CBRA procedure. FIG. 12 is a sequence diagram illustrating an example of a CFRA procedure. FIG. 13 is a table diagram illustrating existing (traditional) random access configuration. FIG. 14 is a diagram schematically illustrating random access configuration when the PRACH configuration index in FIG. 7 is a specific value. FIG. 15 is a diagram illustrating an existing information element "ssb-perRACH-OccasionAndCB-PreamblesPerSSB" that defines the relationship between SSB and RO. FIG. 16 is a sequence diagram illustrating transmission of an SSB, an SIB1 including an additional PRACH configuration index, and a PRACH according to an embodiment of the present disclosure. FIG. 17 is a sequence diagram illustrating transmission of an SSB, an SIB1 including a conventional PRACH configuration index, and a PRACH according to an embodiment of the present disclosure. FIG. 18 is a diagram of a new table for random access configuration for repeated PRACH transmission according to an embodiment of the present disclosure. FIG. 1 is a diagram illustrating an extension to an existing information element "RACH-ConfigCommon" according to an embodiment of the present disclosure. FIG. 2 is a diagram illustrating determining a physical root sequence index from a logical root sequence index for repeated PRACH transmissions according to an embodiment of the present disclosure. FIG. 3 is a diagram illustrating an extension to an existing preamble group according to an embodiment of the present disclosure. FIG. 4 is a block diagram illustrating an example of the configuration of a gNB (base station) according to an embodiment of the present disclosure. FIG. 5 is a block diagram illustrating an example of the configuration of a UE (terminal) according to an embodiment of the present disclosure. FIG. 6 is a diagram illustrating an example of the hardware configuration of a gNB (base station) and a UE (terminal) according to an embodiment of the present disclosure. FIG. 7 is a diagram illustrating an example of the configuration of a vehicle according to an embodiment of the present disclosure.

[0013] Hereinafter, an embodiment according to one aspect of the present disclosure will be described with reference to the drawings.

[0014] 1 is a diagram illustrating an example of a wireless communication system 10 according to an embodiment of the present disclosure. The wireless communication system 10 is a wireless communication system conforming to 5G NR, and includes a Next Generation-Radio Access Network 20 (hereinafter, NG-RAN 20) and a terminal 200 (hereinafter, UE (User Equipment) 200).

[0015] The wireless communication system 10 may be a wireless communication system conforming to a system called Beyond 5G, 5G Evolution, or 6G.

[0016] The NG-RAN 20 includes a base station 100A (hereinafter, gNB 100A) and a base station 100B (hereinafter, gNB 100B). When there is no need to distinguish between the gNB 100A, the gNB 100B, etc., they are collectively referred to as gNB 100. Furthermore, the number of gNBs and UEs is not limited to the example shown in FIG. 1.

[0017] The NG-RAN 20 actually includes multiple NG-RAN nodes, specifically, gNBs (or ng-eNBs), and is connected to a 5G-compliant core network (5GC, not shown). The NG-RAN 20 and 5GC may simply be referred to as "networks." In the following, the term "gNB" may be replaced with "network (NW)."

[0018] The gNB 100A and the gNB 100B are base stations conforming to 5G and perform 5G wireless communication with the UE 200. The gNB 100A, the gNB 100B, and the UE 200 are MIMO (Multiple-Input Multiple-Output) that generates a more directional beam BM by controlling radio signals transmitted from multiple antenna elements, carrier aggregation (CA) that uses a bundle of multiple component carriers (CC), and dual connectivity (DC) that communicates between the UE and each of two NG-RAN nodes.

[0019] The wireless communication system 10 may also support multiple frequency ranges (FR). Fig. 2 is a diagram showing an example of FRs used in the wireless communication system 10. As shown in Fig. 2, the wireless communication system 10 may support FR1 and FR2. The frequency bands of each FR are, for example, as follows: FR1: 410 MHz to 7.125 GHz FR2: 24.25 GHz to 52.6 GHz

[0020] FR1 may use a sub-carrier spacing (SCS) of 15 kHz, 30 kHz, or 60 kHz, and a bandwidth (BW) of 5 to 100 MHz. FR2 is a higher frequency than FR1, and may use an SCS of 60 kHz or 120 kHz (including 240 kHz), and a bandwidth (BW) of 50 to 400 MHz.

[0021] Note that SCS may be interpreted as numerology, which is defined in 3GPP TS 38.300 and corresponds to one subcarrier spacing in the frequency domain.

[0022] Furthermore, the wireless communication system 10 may support a frequency band higher than the FR2 frequency band. Specifically, the wireless communication system 10 may support a frequency band exceeding 52.6 GHz up to 114.25 GHz. For convenience, such a high frequency band may be referred to as "FR2x." When using a frequency band exceeding 52.6 GHz, CP-OFDM (Cyclic Prefix-Orthogonal Frequency Division Multiplexing) / DFT-S-OFDM (Discrete Fourier Transform-Spread-Orthogonal Frequency Division Multiplexing) with a larger SCS may be applied.

[0023] 3 is a diagram showing an example of the configuration of a radio frame (system frame), subframe, and slot used in the radio communication system 10. As shown in FIG. 3, one slot is composed of 14 symbols, and the larger (wider) the SCS, the shorter the symbol period (and slot period). However, the SCS is not limited to the interval (frequency) shown in FIG. 3. For example, 480 kHz, 960 kHz, etc. may be used as the SCS.

[0024] Furthermore, the number of symbols constituting one slot does not necessarily have to be 14 (for example, it may be 28 or 56 symbols, etc.) Furthermore, the number of slots per subframe may differ depending on the SCS.

[0025] 3 may be called a time domain, a symbol period, a symbol time, etc. The frequency direction may be called a frequency domain, a resource block, a subcarrier, a bandwidth part (BWP), etc.

[0026] The wireless communication system 10 may support coverage enhancement (CE) that expands the coverage of the cell (or physical channel) formed by the gNB 100. In coverage enhancement, a mechanism for increasing the success rate of reception of various physical channels, such as repeated transmission of the PRACH, may be provided.

[0027] For example, UE200 receives information related to the random access procedure from gNB100 as a downlink (DL) signal (e.g., SIB1 (System Information Block Type 1) etc.).

[0028] Further, for example, UE 200 transmits PRACH as an UL signal to gNB 100 using a RACH occasion (RO), which is a resource for transmitting a random access preamble. For example, UE 200 repeatedly transmits PRACH as an UL signal to gNB 100.

[0029] The UL signal may include, for example, a UL data signal and control information. For example, the UL signal may include information related to the processing capability of the UE 200 (e.g., UE capability). The UL signal may also include a reference signal.

[0030] Channels used for transmitting UL signals include, for example, data channels and control channels. For example, the data channel may include a physical uplink shared channel (PUSCH), and the control channel may include a physical uplink control channel (PUCCH). For example, the UE 200 transmits control information using the PUCCH and transmits UL data signals using the PUSCH. Note that the PUSCH is an example of an uplink shared channel, and the PUCCH is an example of an uplink control channel. The shared channel may also be called a data channel.

[0031] The reference signal included in the UL signal may include, for example, at least one of a Demodulation Reference Signal (DMRS), a Phase Tracking Reference Signal (PTRS), a Channel State Information - Reference Signal (CSI-RS), a Sounding Reference Signal (SRS), and a Positioning Reference Signal (PRS) for position information. For example, reference signals such as the DMRS and PTRS are used to demodulate the UL data signal and are transmitted using the PUSCH.

[0032] Meanwhile, in response to the operation of UE200, gNB100 transmits information related to the RACH procedure to UE200 as a DL signal (e.g., SIB1, etc.).

[0033] Also, for example, gNB100 receives PRACH as an UL signal from UE200. For example, gNB100 repeatedly receives PRACH from UE200 as an UL signal.

[0034] Channels used for transmitting DL signals include, for example, data channels and control channels. For example, the data channel may include a physical downlink shared channel (PDSCH), and the control channel may include a physical downlink control channel (PDCCH). For example, the gNB 100 transmits control information to the UE 200 using the PDCCH, and transmits DL data signals using the PDSCH. Note that the PDSCH is an example of a downlink shared channel, and the PDCCH is an example of a downlink control channel. Note that the PDCCH may be interpreted as downlink control information (DCI), control information, etc. transmitted in the PDCCH.

[0035] The reference signal included in the DL signal may include, for example, at least one of a DMRS, a PTRS, a CSI-RS, an SRSRS, and a PRS for location information. For example, the reference signal such as the DMRS or the PTRS is used for demodulating the DL data signal and is transmitted using the PDSCH.

[0036] <Random Access Procedure> The NR random access procedure is performed for various purposes such as initial access, recovery from beam interference, handover, etc. The random access procedure includes a CBRA (Contention Based Random Access) procedure as a contention-based random access procedure and a CFRA (Contention Free Random Access) procedure as a contention-free random access procedure. Since the CBRA procedure is initiated by the UE 200 voluntarily, collisions may occur when multiple UEs 200 simultaneously initiate the random access procedure. On the other hand, CFRA allows the gNB 100 to instruct the connected UE 200 to perform the random access procedure so that collisions do not occur between multiple UEs 200.

[0037] In NR, a random access procedure may be performed by selecting a Synchronization Signal (SS) / Physical Broadcast Channel (PBCH) block, or by selecting a CSI-RS. The SS / PBCH block may be referred to as an SSB or synchronization signal, and the CSI-RS may be referred to as a reference signal.

[0038] FIG. 4 is a sequence diagram illustrating an example of a CBRA procedure.

[0039] For example, the gNB 100 transmits an SSB for each beam, and the UE 200 monitors the SSB of each beam. The UE 200 selects an SSB from among the multiple SSBs whose received power (RSRP: Reference Signal Received Power) is greater than a threshold (or is equal to or greater than a threshold), and transmits a random access preamble to the gNB 100 via a PRACH using an RO associated with (corresponding to) the selected SSB (step S101). The random access preamble (sometimes abbreviated as an RA preamble or RA preamble) may be appropriately referred to as a preamble, a PRACH preamble, a message 1, an Msg1, or the like.

[0040] The gNB 100 transmits a response message to Msg1 as a second message to the UE 200 via the PDSCH (step S102). This response message (second message) may be appropriately referred to as a random access response (RAR), RA Response, message 2 (Message 2), Msg2, or the like. After transmitting Msg1, the UE 200 may monitor the PDCCH used for scheduling the PDSCH including Msg2. Msg2 may include an uplink grant (UL Grant) (RAR uplink grant) used for scheduling the PUSCH including the third message transmitted by the UE 200.

[0041] The UE 200 transmits the PUSCH scheduled by the RAR uplink grant as a third message (step S103). For example, the UE 200 transmits a radio resource control (RRC) connection request, an RRC connection re-establishment request, or the like to the gNB 100 via the PUSCH. The third message may be appropriately referred to as a message 3, Msg 3, an RRC connection request, or the like.

[0042] The gNB 100 transmits a contention resolution message (Contention Resolution Message) as a fourth message via the PDSCH (step S104). This contention resolution message (fourth message) may be referred to as Message 4, Msg 4, or the like, as appropriate. After transmitting Msg 3, the UE 200 may monitor the PDCCH used for scheduling the PDSCH including Msg 4. Msg 4 may include a contention resolution ID (UE contention resolution ID). The contention resolution ID may be used to resolve contention between multiple UEs 200 transmitting signals using the same radio resources. If the contention resolution ID included in the Msg 4 received by the UE 200 is the same value as the ID for identifying the UE 200, the UE 200 determines that contention resolution is successful and may set the value of the Temporary Cell-Radio Network Temporary Identifier (TC-RNTI) in the Cell-Radio Network Temporary Identifier (C-RNTI) field. When the value of the TC-RNTI is set in the C-RNTI field, the UE 200 may consider that the RRC connection is completed. Msg4 may be referred to as an RRC connection setup, etc.

[0043] UE200, whose RRC connection has been completed, may transmit an Ack (Acknowledgement) via the PUCCH (PUCCH resource) indicated by the PUCCH resource indication field included in the PDCCH that scheduled Msg4 in order to notify gNB100 that the RRC connection has been completed. Also, after the RRC connection is established, UE200 may transmit UE capability to gNB100. The above-described random access procedure may be referred to as a Type 1 RACH procedure, a 4-step RACH procedure, a Type 1 RACH, a 4-step RACH, or the like.

[0044] FIG. 5 is a sequence diagram showing another example of the CBRA procedure.

[0045] The UE 200 transmits a message including an RA preamble and data to the gNB 100 (step S201). As an example, the UE 200 selects an RO in the same manner as the selection of an RO in the 4-step RACH procedure, transmits an RA preamble in the RO, and transmits data in a PUSCH resource associated with the RO. This message may be appropriately referred to as Message A, Msg A, etc. The RA preamble and data here may correspond to Msg 1 and Msg 3 in the 4-step RACH procedure, respectively. In this procedure, the resource for transmitting data is not limited to a PUSCH resource, and may be any channel resource for transmitting data (or control information).

[0046] The gNB 100 transmits the response message as a second message to the UE 200 (step S202). The response message (second message) may be appropriately referred to as Message B, Msg B, etc. The content included in Message B may correspond to, for example, Msg 2 and Msg 4 in the 4-step RACH procedure.

[0047] UE200, whose RRC connection has been completed, may transmit an Ack via PUCCH (PUCCH resource) to notify gNB100 that the RRC connection has been completed. Also, after the RRC connection is established, UE200 may transmit UE capability to gNB100. The above-described random access procedure may be referred to as a Type 2 RACH procedure, a 2-step RACH procedure, a Type 2 RACH, a 2-step RACH, or the like.

[0048] FIG. 6 is a sequence diagram illustrating an example of a CFRA procedure.

[0049] The UE 200 is requested to transmit an RA preamble (Msg1) from the gNB 100. Here, the gNB 100 allocates the RA preamble (Msg1) via dedicated signaling (step S301). The PDCCH for such dedicated signaling may be referred to as a PDCCH order. The UE 200 may monitor the PDCCH (PDCCH order) to perform resource allocation for Msg1.

[0050] UE200 transmits the above-mentioned Msg1 to gNB100 (step S302).

[0051] The gNB100 transmits the above-mentioned Msg2 to the UE200 (step S303). After the RRC connection is completed, the UE200 may transmit an Ack via the PUCCH (PUCCH resource) to notify the gNB100 that the RRC connection has been completed. After the RRC connection is established, the UE200 may transmit the UE capability to the gNB100.

[0052] In this embodiment, in order to achieve coverage extension in the random access procedure, UE 200 may repeatedly transmit Msg1 (and therefore PRACH) in, for example, the above-described 4-step RACH procedure shown in Fig. 4 and the CFRA procedure shown in Fig. 6. However, in the present disclosure, Msg1 (and therefore PRACH) may also be repeatedly transmitted in the above-described 2-step RACH procedure shown in Fig. 5.

[0053] <Discussion> In relation to the transmission of PRACH, RACH occasion (RO) configurations (which may also be referred to as random access configurations) for transmitting PRACH are specified in, for example, Table 6.3.3.2-2 / 3 / 4 of Non-Patent Document 1. As an example, Fig. 7 shows a part of Table 6.3.3.2-3 which shows existing (conventional) random access configurations for FR1 and unpaired spectrum described in Non-Patent Document 1.

[0054] Here, a configuration in which the PRACH configuration index shown in FIG. 7 is 75, which is determined by the information element (RRC parameter) "prach-ConfigurationIndex" in SIB1, will be described as an example.

[0055] When the PRACH configuration index is 75, A1 is specified as the PRACH preamble format (which may also be referred to as the PRACH format, the preamble format, etc.). f mod x(=2) = y(=1)”(n f As indicated by "SFN: System Frame Number"), ROs are placed in system frames with odd system frame numbers, and are not placed in system frames with even system frame numbers. ROs are placed in subframes with subframe numbers 4 and 9, and the starting symbol of the RO is 0. As indicated by "Number of PRACH slots within a subframe," the number of PRACH slots in one subframe is 2, and "N t RA,slot , number of time-domain PRACH occasions within a PRACH slot" and "N dur RAAs indicated by ", PRACH duration", the number of ROs in one PRACH slot is 6, and each RO has 2 symbols. Note that the fact that each RO has 2 symbols is associated with the PRACH preamble format being A1. This is shown diagrammatically in Figure 8.

[0056] Furthermore, in relation to PRACH transmission, for example, "8.1 Random access preamble" in Non-Patent Document 2 defines the relationship between SSB and RO. Fig. 9 shows the information element "ssb-perRACH-OccasionAndCB-PreamblesPerSSB" that defines the relationship between SSB and RO. Note that the information element "ssb-perRACH-OccasionAndCB-PreamblesPerSSB" is included in the information element "RACH-ConfigCommon."

[0057] The information element "ssb-perRACH-OccasionAndCB-PreamblesPerSSB" has two meanings. The "CHOICE" part indicates the number of SSBs (indexes) (number of beams) per RO. For example, the value "oneEight" indicates that one SSB is associated with eight ROs, the value "oneFourth" indicates that one SSB is associated with four ROs, etc. The "ENUMERATED" part indicates the number of available preambles (preambles in CBRA) per SSB (index) (per valid RO). For example, the value "n4" indicates that one SSB is associated with four preambles, the value "n8" indicates that one SSB is associated with eight preambles, etc.

[0058] Furthermore, in relation to the transmission of the PRACH, for example, in "8.1 Random access preamble" of Non-Patent Document 2, an association period and an association pattern period are defined.

[0059] The association period is determined by the N ssb-PositionInBurst information element in SIB1 or the N ssb-PositionInBurst information element in the ServingCellConfigCommon information element, which is used to map (associate) an SSB to an RO. TX SSB The PRACH configuration period is a period obtained by repeating the PRACH configuration period, given by x (the number of system frames) shown in Figure 7, a minimum number of times so that each SSB (index) (all SSBs (indexes)) is mapped to an RO at least once within the association period. The PRACH configuration period is 10 ms (x = 1), 20 ms (x = 2), 40 ms (x = 4), 80 ms (x = 8), or 160 ms (x = 16).

[0060] An association pattern period is a period that includes one or more association periods and is determined so that the pattern between RO and SSB is repeated at most every 160 milliseconds.

[0061] Furthermore, in relation to PRACH transmission, for example, Table 6.3.3.1-1 of Non-Patent Document 1 shows a PRACH preamble format when the PRACH preamble sequence length is 839 (long sequence). Similarly, for example, Table 6.3.3.1-2 of Non-Patent Document 1 shows a PRACH preamble format when the PRACH preamble sequence length is 139 (short sequence). Furthermore, for example, Table 6.3.3.2-1 of Non-Patent Document 1 shows the relationship between the PRACH preamble sequence length and the PRACH SCS.

[0062] In order to extend coverage in a random access procedure, for example, when repeatedly transmitting the PRACH according to the existing random access configuration shown in Fig. 7, if the repeated transmission of the PRACH is not appropriately controlled, there is a risk that the initial transmission of the PRACH (which may also be referred to as a first transmission, initial transmission, initial transmission, etc.) and the repeated transmission of the PRACH will collide, resulting in a deterioration in communication quality. However, specific operations for suppressing or avoiding such collisions have not yet been specified. Furthermore, if repeated transmission of the PRACH is performed when it is not necessary, unnecessary resources will be used, which is a problem in terms of resource efficiency.

[0063] In order to suppress or avoid such collisions, it is conceivable to support additional resources (e.g., additional ROs) for repeated transmission of the PRACH. However, there is no provision on whether or not to increase the (additional) resources for repeated transmission of the PRACH, and if the resources are increased, how to increase the additional resources.

[0064] For example, although there are provisions as shown in Figures 7 and 8, when increasing (additional) resources, the following points are not specified at all: (1-1) How to define additional resources (and / or settings related to additional resources, and / or settings related to PRACH sequences transmitted on additional resources) (1-2) Whether to use additional resources (and / or settings related to additional resources, and / or settings related to PRACH sequences transmitted on additional resources) (1-3) What resources can be used for additional resources

[0065] Furthermore, although there are provisions such as those shown in FIG. 9 and the above-mentioned provisions regarding the PRACH preamble sequence length, the following points are not specified when (additional) resources are not increased: (1-4) Whether to increase the number of usable preambles per RO without increasing the RO, and if the number of usable preambles is increased, how to increase the number of usable preambles.

[0066] On the other hand, when additional resources for repeated transmission of PRACH are not supported (when initial transmission of PRACH and repeated transmission of PRACH are performed in the same existing RO), the following points are not specified at all: (2-1) Whether or not to explicitly suppress or avoid collisions between initial transmission of PRACH and repeated transmission of PRACH in the existing RO, and if collisions are explicitly suppressed or avoided, how to explicitly suppress or avoid collisions

[0067] Therefore, solutions 1, 2, 3, 4, and 5 for the above points (1-1), (1-2), (1-3), (1-4), and (2-1), respectively, are described below. Note that, unless otherwise specified, the CBRA procedure (e.g., a random access procedure during initial access) is mainly described below, but the present disclosure is also applicable to random access procedures other than the CBRA procedure (CFRA procedure). Furthermore, unless otherwise specified, the following mainly describes repeated transmission of the PRACH using the same beam as the SSB, but the present disclosure is equally applicable to repeated transmission of the PRACH using a beam different from the SSB.

[0068] <Solution 1> First, a solution to "(1-1) How to define additional resources for repeated transmission of PRACH (and / or settings related to the additional resources, and / or settings related to the PRACH sequence transmitted on the additional resources)" will be described. Note that in the following description including Solution 1, unless otherwise specified, the initial transmission of PRACH may be performed in the same manner as in 3GPP Release 15, 16, or 17, including the random access setting (RO setting) described with reference to FIG. 7 .

[0069] [Proposal P1-1] In proposal P1-1, an additional RO for repeated transmission of the PRACH may be defined by reusing the existing RO configuration shown in FIG. 7. Specifically, in proposal P1-1, an additional "PRACH configuration index" for the additional RO, which is different from the PRACH configuration index for the initial transmission of the PRACH, may be configured, notified, or instructed by the gNB 100 to the UE 200. Note that the "PRACH configuration index" may also be referred to as "random access configuration information," "information related to the configuration of random access," "random access channel transmission configuration information," "information related to the configuration of random access channel transmission," "information related to resources for random access," "information related to resources for random access channel transmission," "information related to resources for transmitting the random access channel," or the like.

[0070] Option 1 In Option 1, the additional PRACH configuration index may be configured, signaled, or indicated in at least one of the following:

[0071] Option 1-1 The additional PRACH configuration index may be set, notified or indicated by gNB100 in SIB1 (e.g., in the information element "RACH-ConfigGeneric") after transmitting the SSB, as shown in FIG. 10, or may be set, notified or indicated in other system information such as S1B2.

[0072] Option 1-2 The additional PRACH configuration index may be configured, notified, or indicated in a dedicated RRC configuration (for example, in the information element "RACH-ConfigDedicated") by the gNB 100. The RRC configuration may be appropriately referred to as RRC signaling, an RRC message, an RRC parameter, simply RRC, or the like.

[0073] Option 1-3 The additional PRACH configuration index may be configured, notified or indicated by gNB100 in the PDCCH scheduling the RAR (Msg2).

[0074] Option 1-4 The additional PRACH configuration index may be configured, notified or indicated by gNB100 in the PDSCH including the RAR (Msg2).

[0075] Option 2 In Option 2, the number of additional PRACH configuration indexes configured, signaled, or indicated for repeated PRACH transmission as proposed in Option 1 may be the numbers described below.

[0076] Option 2-1 The number of additional PRACH configuration indexes may be the same as the number of repeated PRACH transmissions (e.g., "N" shown in FIG. 10 ). That is, the additional PRACH configuration index for each transmission in the repeated PRACH transmissions may be configured, notified, or indicated as described in Option 1 above. The additional PRACH configuration index may be different between the PRACH configuration indexes for each transmission in the repeated PRACH transmissions, or may be the same between the PRACH configuration indexes for at least some of the transmissions in the repeated PRACH transmissions. Note that in the present application, the repeated PRACH transmissions are described as not including an initial PRACH transmission, but the repeated PRACH transmissions may also include an initial PRACH transmission. When the repeated PRACH transmissions do not include an initial PRACH transmission, the number of additional PRACH configuration indexes may be the same as the number of repeated PRACH transmissions minus 1. According to Option 2-1, flexible random access settings can be made for each transmission in repeated PRACH transmissions.

[0077] Option 2-2 The additional PRACH configuration index may be common (the same) for all transmissions in the repeated transmission of the PRACH. That is, the number of additional PRACH configuration indexes may be 1. Therefore, in this case, a total of two PRACH configuration indexes, namely, a PRACH configuration index for the initial transmission of the PRACH and a PRACH configuration index for all transmissions in the repeated transmission of the PRACH, may be configured, notified, or indicated as described in Option 1 above. According to Option 2-2, it is possible to suppress an increase in the amount of signaling related to random access configuration.

[0078] Option 3 In Option 3, the PRACH configuration index for repeated transmission of the PRACH may be restricted so as to satisfy the following predetermined conditions.

[0079] Option 3-1 The additional PRACH configuration index may be set, notified, or instructed by the gNB 100 so that the RO set for repeated transmission of the PRACH does not (completely) overlap (different) (predetermined condition) with the RO set by the PRACH configuration index for initial transmission of the PRACH. According to this Option 3-1, it is possible to avoid collision between the initial transmission of the PRACH and the repeated transmission of the PRACH.

[0080] In proposal P1-1, UE 200 may receive from gNB 100 a PRACH configuration index (first information related to a first resource for transmitting a random access channel) for initial transmission of the PRACH. UE 200 may receive from gNB 100 the above-mentioned number of additional PRACH configuration indexes (second information related to a second resource, at least partially different from the first resource, for transmitting the random access channel) for repeated transmission of the PRACH. UE 200 may set (determine) an RO (resource) for the initial transmission of the PRACH based on the received PRACH configuration index, and may set (determine) an additional RO for repeated transmission of the PRACH that is different from the RO for the initial transmission. More specifically, UE 200 may set (determine) a PRACH preamble format and an RO in the table shown in FIG. 7 corresponding to the received PRACH configuration index and additional PRACH configuration index. Then, UE200 may initially transmit PRACH to gNB100 using the set (determined) RO, and repeatedly transmit PRACH to gNB100 using the set (determined) additional RO.

[0081] As described above, according to Options 1 to 3 of Proposal P1-1, the RO for the initial transmission of the PRACH and the RO for the repeated transmission of the PRACH do not at least partially overlap (are different), so that it is possible to suppress or avoid collisions between the initial transmission of the PRACH and the repeated transmission of the PRACH. Therefore, it is possible to appropriately perform repeated transmission of the PRACH in the random access procedure.

[0082] [Proposal P1-2] In proposal P1-2, an additional RO for repeated transmission of PRACH may be defined by associating it with the existing (conventional) RO configuration shown in Fig. 7. Specifically, in proposal P1-2, the additional RO may be defined based on the configured RO by following a predetermined rule. In proposal P1-2, the additional PRACH configuration index for the additional RO proposed in proposal P1-1 described above is not required.

[0083] Option 1 In Option 1, the above-mentioned "set RO" may be as follows:

[0084] Option 1-1 The above "configured RO" may be the RO configured by the PRACH configuration index for initial transmission (the information element "prach-ConfigurationIndex" in SIB1) shown in Fig. 11. Note that the term "conventional" shown in Fig. 11 may mean that it is for initial transmission.

[0085] Option 2 In Option 2, the "predetermined rule" may be at least one of the following:

[0086] Option 2-1: One or more system frames different from the system frame set by the PRACH configuration index for initial transmission may be statically configured (determined or selected) based on the above-described configured system frame (according to a predetermined rule). In this case, the statically configured one or more system frames are different from the system frame set for initial transmission, but the subframes (subframe numbers, positions within the system frames) and PRACH slots (slot numbers, positions within the subframes) within the one or more system frames may be the same as the subframes (subframe numbers, positions within the system frames) and PRACH slots (slot numbers, positions within the subframes) set for initial transmission, respectively. For example, as shown in FIG. 11 , the statically configured one or more system frames may be system frames subsequent to (e.g., immediately after) the system frame set for initial transmission. Alternatively, the statically configured one or more system frames may be system frames prior to (e.g., immediately before) the system frame set for initial transmission. The UE 200 may repeatedly transmit the PRACH using such a static system frame (PRACH slots within subframes within the static system frame).

[0087] Option 2-2: One or more subframes different from the subframes set by the PRACH configuration index for initial transmission may be statically set (determined or selected) based on the set subframes (according to a predetermined rule). In this case, the statically set one or more subframes may be other subframes within the (same) system frame set for initial transmission, and the PRACH slots (slot numbers, positions within subframes) set within the selected one or more system frames may be the same as the PRACH slots (slot numbers, positions within subframes) set for initial transmission. For example, as in Option 2-1 above, the one or more set subframes may be subframes before (e.g., immediately before) or after (e.g., immediately after) the subframe set for initial transmission. The UE 200 may repeatedly transmit the PRACH using such static subframes (within the system frame).

[0088] Option 2-3: A PRACH slot different from the PRACH slot set by the PRACH configuration index for initial transmission may be statically set (determined or selected) based on the set PRACH slot (according to a predetermined rule). In this case, the statically set PRACH slot may be another PRACH slot in the same subframe in the same system frame set for initial transmission. The UE 200 may repeatedly transmit the PRACH using such a static PRACH slot (in a subframe in the system frame).

[0089] Option 2-4 The above "predetermined rule" may be any combination of Options 2-1 to 2-3. In one example, one or more system frames different from the system frame set by the PRACH configuration index for initial transmission and one or more subframes different from the subframe set by the PRACH configuration index are fixedly configured (determined or selected), and the PRACH slot may be the same PRACH slot as the PRACH slot set for initial transmission in terms of slot number (position within a subframe). In this case, the UE 200 may repeatedly transmit the PRACH using a PRACH slot in a fixed subframe within such a fixed system frame. In another example, one or more subframes different from the subframe set by the PRACH configuration index for initial transmission and one or more PRACH slots different from the PRACH slot set by the PRACH configuration index are fixedly configured (determined or selected), and the system frame may be the system frame set for initial transmission. The UE 200 may repeatedly transmit the PRACH using a fixed PRACH slot in a fixed subframe in a system frame.

[0090] In the above, it is possible that a repeat transmission of the PRACH is performed temporally before a system frame or the like set by a conventional PRACH configuration index. However, in the present disclosure, regardless of such a case, transmission of the PRACH using an RO set by a conventional PRACH configuration index is referred to as an initial transmission of the PRACH for convenience. The initial transmission of the PRACH may also be referred to as an initial PRACH transmission, a conventional transmission of the PRACH, a conventional PRACH transmission, an existing transmission of the PRACH, an existing PRACH transmission, etc. Furthermore, a repeat transmission of the PRACH may also be referred to as a repeat PRACH transmission, an additional transmission of the PRACH, an additional PRACH transmission, etc.

[0091] In summary, the system frame for initial transmission of PRACH, the subframe within that system frame, and the slot within that subframe may differ from at least one of the corresponding system frame, subframe within that system frame, and slot within that subframe for repeated transmission of PRACH in terms of system frame number, subframe number, and slot number, respectively.

[0092] As described above, in the configuration (determination or selection) of the “additional RO” under the “predetermined rule” shown in Option 2, the RO (resource) configured by the PRACH configuration index (the information element “prach-ConfigurationIndex” in SIB1) for the initial transmission of the PRACH can be excluded.

[0093] Option 3 In Option 3, the additional RO for repeated transmission of PRACH may be defined as follows:

[0094] Option 3-1: An additional RO for PRACH repeat transmission may be defined by defining a new table for extending the existing RO configuration shown in FIG. 7 and associating the new table with the existing RO configuration shown in FIG. 7. FIG. 12 is a diagram of a new table for random access configuration for PRACH repeat transmission according to this embodiment. This table may include only a portion of the rows of the table shown in FIG. 7. The table shown in FIG. 12 and the table shown in FIG. 7 are associated by linking the "PRACH configuration index (for initial)" field shown in FIG. 12 with the "PRACH configuration index" field shown in FIG. 7. Note that in FIG. 12, the symbol "-" indicates that the value is the same as the value of the corresponding field in the table shown in FIG. 7. Specifically, when the PRACH configuration index for initial transmission is 75, the row in the table shown in FIG. 7 where the PRACH configuration index is 75 is also referenced for the RO configuration for repeat transmission. In the table shown in FIG. 12 , when the PRACH configuration index for initial transmission is 75, unlike the RO configuration for initial transmission shown in FIG. 7 , subframes with subframe numbers 3 and 8 are configured (determined or selected) for additional ROs. The above example corresponds to Option 2-2 of the above-described proposal P1-2, but configurations corresponding to Option 2-1, Option 2-2, and / or Option 2-3 of the above-described proposal P1-2 may also be reflected in the table shown in FIG. 12 . In this way, when a PRACH configuration index for initial transmission is configured, whether or not an additional RO for repeated transmission corresponding to the PRACH configuration index exists, and if an additional RO for repeated transmission exists, the location of the additional RO for repeated transmission is defined in advance in the table shown in FIG. 12 . Therefore, when a PRACH configuration index for initial transmission is configured, the UE 200 can confirm the configuration of an additional RO for repeated transmission corresponding to the PRACH configuration index by referring to the table shown in FIG. 7 and the table shown in FIG. 12 .In the table shown in Fig. 12, when a value is the same as a value in a corresponding field in the table shown in Fig. 7, the same value may be written instead of omitting the value. In this case, the UE 200 only needs to refer to the table shown in Fig. 12 to confirm an additional RO for repeated transmission.

[0095] In proposal P1-2, UE 200 may receive a PRACH configuration index (first information related to a first resource for transmitting a random access channel) for initial transmission of the PRACH from gNB 100. UE 200 may set (determine) an RO (resource) (first system frame, subframe within the first system frame, and first slot within the first subframe) for the initial transmission of the PRACH based on the received PRACH configuration index. UE 200 may set (determine) an RO (resource) (second system frame, subframe within the second system frame, and second slot within the second subframe) to be used for repeated transmission of the PRACH, which is at least partially different from the resource used for the initial transmission of the PRACH in frame number, subframe number, and slot number based on the received PRACH configuration index (second information related to a second resource for transmitting the random access channel, which is at least partially different from the first resource). Then, UE200 may initially transmit PRACH to gNB100 using the set (determined) RO, and repeatedly transmit PRACH to gNB100 using the set (determined) RO.

[0096] As described above, according to Options 1 to 3 of Proposal P1-2, the RO for the initial transmission of the PRACH and the RO for the repeated transmission of the PRACH do not at least partially overlap (are different), so that it is possible to suppress or avoid collisions between the initial transmission of the conflicting PRACH and the repeated transmission of the PRACH. Therefore, it is possible to appropriately perform repeated transmission of the PRACH in the random access procedure. Furthermore, according to Options 1 to 3 of Proposal P1-2, an additional PRACH configuration index for the additional RO is not required, and it is possible to suppress an increase in the amount of signaling.

[0097] [Proposal P1-3] In proposal P1-3, information related to resources for transmitting a predetermined RO or PRACH may be configured, notified, or instructed by gNB100 to UE200 according to a method different from the above-described RO configuration (resource configuration). Specifically, in proposal P1-3, a predetermined PRACH that is not limited to repeated transmission may be transmitted by UE200 according to a dynamic notification or instruction including information related to PRACH transmission from gNB100, in order to make it different from the resource configuration, etc., configured for the initial transmission of PRACH. Note that "information related to PRACH transmission" may also be referred to as "random access configuration information," "information related to random access configuration," "random access channel transmission configuration information," "information related to random access channel transmission configuration," "information related to resources for random access," "information related to resources for random access channel transmission," "information related to resources for transmitting a random access channel," or the like.

[0098] Option 1 In Option 1, complying with the above-mentioned "dynamic notification or instruction" may be at least one of the following.

[0099] Option 1-1 Complying with the above-mentioned "dynamic notification or instruction" may be complying with "PDCCH (DCI)."

[0100] Option 1-2: Complying with the above-mentioned "dynamic notification or instruction" may be complying with "MAC-CE (Medium Access Control - Control Element)."

[0101] Option 2 In Option 2, the above-mentioned "information regarding PRACH transmission" may be at least one of the following:

[0102] Option 2-1 The above-mentioned "information related to PRACH transmission" may be (information indicating) time resources and / or frequency resources used for PRACH transmission.

[0103] Option 2-2 The above-mentioned "information related to PRACH transmission" may be (information indicating) a PRACH preamble format.

[0104] Option 2-3 The above-mentioned "information related to PRACH transmission" may be (information indicating) a cyclic shift index.

[0105] Option 2-4 The above-mentioned "information related to PRACH transmission" may be (information indicating) a root sequence index.

[0106] Option 2-5 The above-mentioned "information related to PRACH transmission" may be (information indicating) a preamble index and / or a preamble group.

[0107] Option 2' In Option 2', if some of the information in Option 2 above is not dynamically notified or indicated, the following may be followed.

[0108] Option 2'-1: If some of the information in Option 2 above is not dynamically signaled or indicated, the corresponding information configured for the initial PRACH transmission (for example, configured by the PRACH configuration index) may be reused. For example, if the PRACH preamble format is not dynamically signaled or indicated, the PRACH preamble format configured by the PRACH configuration index shown in FIG. 7 may be used.

[0109] Option 3 In Option 3, proposal P1-3 (transmitting PRACH according to dynamic notification or instructions) may be applied in the limited cases described below.

[0110] Option 3-1 Proposal P1-3 may be applied to repeated transmission of the PRACH. The PRACH may be repeatedly transmitted by the UE 200 according to dynamic notification or instruction.

[0111] Option 3-2 Proposal P1-3 may be applied to PDCCH-initiated random access (PDCCH-order random access). For example, the PRACH may be transmitted by the UE 200 according to dynamic notification or instruction in PDCCH-order random access, which is illustrated in, but not limited to, FIG. 6 .

[0112] Option 3-3 Proposal P1-3 may be applied to CFRA. For example, the PRACH may be transmitted by the UE 200 according to dynamic notification or instruction in CFRA, which is illustrated in, but not limited to, FIG. 6 .

[0113] In proposal P1-3, additional ROs may not be defined for additional transmissions (ie, repeated transmissions) of PRACH.

[0114] In proposal P1-3 (Option 3-1), UE200 may receive from gNB100 a PRACH configuration index (first information related to a first resource for transmitting a random access channel) for initial transmission of the PRACH. UE200 may configure (determine) a resource for the initial transmission of the PRACH based on the received PRACH configuration index. UE200 may receive from gNB100 a dynamic notification or instruction including information related to the PRACH transmission (second information related to a second resource for transmitting the random access channel, which is at least partially different from the first resource). UE200 may configure (determine) a resource for repeated transmission of the PRACH that is different from the resource for the initial transmission of the PRACH based on the dynamic notification or instruction including the received information related to the PRACH transmission. Then, UE200 may initially transmit PRACH to gNB100 using the configured (determined) resources, and may repeatedly transmit PRACH to gNB100 using the configured (determined) resources.

[0115] As described above, according to Options 1 to 3 (3-1) of Proposal P1-3, the resources configured for the initial transmission of the PRACH or the settings related to those resources and the resources configured for the repeated transmission of the PRACH or the settings related to those resources at least partially do not overlap (are different), so it is possible to suppress or avoid collisions between the initial transmission of the PRACH and the repeated transmission of the PRACH. Therefore, the repeated transmission of the PRACH can be performed appropriately in the random access procedure. Furthermore, according to Options 1 to 3 (3-1) of Proposal P1-3, if an additional RO is not defined for the repeated transmission of the PRACH, it is possible to reduce changes to specifications and device implementation.

[0116] <Solution 2> Next, a solution to the question "(1-2) whether to use additional resources for repeated transmission of PRACH (and / or settings related to the additional resources, and / or settings related to the PRACH sequence transmitted on the additional resources)" will be described.

[0117] [Proposal P2-1] In proposal P2-1, whether to use additional resources (and / or settings related to the additional resources) for repeated transmission of PRACH (in other words, whether to trigger repeated transmission of PRACH) may be decided (determined or judged) by gNB100. Specifically, in proposal P2-1, whether to use additional resources for repeated transmission of PRACH may be decided by gNB100, and may be configured, notified, or instructed to UE200 by gNB200. Note that the expression "whether to use additional resources (and / or settings related to the additional resources, and / or settings related to the PRACH sequence transmitted on the additional resources)" may mean the expression "whether to perform repeated transmission of PRACH."

[0118] Option 1 In Option 1, whether to perform repeated transmission of the PRACH may be determined based on at least one of the following:

[0119] Option 1-1: The gNB 100 may determine whether to perform repeated transmission of the PRACH based on a previous PRACH preamble format and / or RO configuration. The previous PRACH preamble format and / or RO configuration may be a PRACH preamble format and / or RO configuration used in one or more previous PRACH transmissions (e.g., initial transmissions) by the UE 200, or may be a PRACH preamble format and / or RO configuration configured via SIB1. Here, the RO configuration may be, for example, the information element "prach-ConfigurationIndex," the information element "zeroCorrelationZoneConfig," or both. For example, the gNB 100 may determine to perform repeated transmission of the PRACH if the previous PRACH preamble format and / or RO configuration imply that repeated transmission of the PRACH is required. These information elements (RRC parameters) may be referred to as "random access setting information", "information related to random access setting", "random access channel transmission setting information", "information related to random access channel transmission setting", "information related to resources for random access", "information related to resources for random access channel transmission", "information related to resources for transmitting the random access channel", etc.

[0120] Option 1-2: The gNB 100 may determine whether to perform repeated transmission of the PRACH based on the received power (RSRP) of a previously received PRACH. For example, the gNB 100 may determine to perform repeated transmission of the PRACH if the received power of a previously received PRACH (e.g., a PRACH initially transmitted and received by the UE 200) is less than a threshold (or is equal to or less than a threshold).

[0121] Note that the above Option 1 may be left to the implementation of the gNB.

[0122] - Option 2 In Option 2, whether to perform repeated transmission of PRACH may be configured, notified or instructed to UE200 by gNB100 in any of the following ways.

[0123] Option 2-1 The gNB 100 may configure, notify, or instruct the UE 200 via a PDCCH whether to repeatedly transmit the PRACH. Such a PDCCH may be a PDCCH (PDCCH order) that instructs random access, a PDCCH that schedules an RAR, and / or a PDCCH (general PDCCH) that schedules one or more DL or UL shared channels.

[0124] Option 2-2 The gNB 100 may configure, notify, or instruct the UE 200 whether to repeatedly transmit the PRACH by MAC-CE. Such a MAC-CE may be a MAC-CE included in a PDSCH including an RAR and / or a MAC-CE included in a PDSCH including a DL shared channel (DL-SCH).

[0125] Option 2-3: The gNB 100 may configure, notify, or instruct the UE 200 whether to repeatedly transmit the PRACH using system information. Such system information may be any SIB, such as SIB1 or SIB2.

[0126] Option 2-4: The gNB100 may configure, notify or instruct the UE200 via RRC configuration whether to repeatedly transmit the PRACH.

[0127] Option 2-5 gNB100 may configure, notify or instruct UE200 whether to repeatedly transmit PRACH using any combination of Options 2-1 to 2-5 above.

[0128] In proposal P2-1, UE200 receives information from gNB100 regarding whether to perform repeated transmission of PRACH, and if repeated transmission of PRACH is to be performed, UE200 may set (determine) additional RO or additional resources, for example, according to the above-mentioned proposals P1-1 to P1-3, and repeatedly transmit PRACH to gNB100 using the set (determined) additional RO or additional resources.

[0129] As described above, according to Options 1 and 2 of Proposal P2-1, repeat transmission of the PRACH is performed only when coverage extension (repeated transmission of the PRACH) is assumed to be necessary, which makes it possible to suppress or avoid the use of unnecessary resources and is advantageous in terms of resource efficiency. Therefore, repeat transmission of the PRACH can be performed appropriately in the random access procedure. Furthermore, for example, when an additional RO or additional resources are configured (determined) according to Proposals P1-1 to P1-3 described above, the resources for the initial transmission of the PRACH and the resources for the repeat transmission of the PRACH do not at least partially overlap, so that collisions between the initial transmission of the PRACH and the repeat transmission of the PRACH can be suppressed or avoided.

[0130] [Proposal P2-2] In proposal P2-2, whether to use the additional resource (and / or the configuration related to the additional resource) for repeated transmission of the PRACH may be determined (judged or determined) by the UE 200.

[0131] Option 1 In Option 1, whether to perform repeated transmission of the PRACH may be implicitly determined by the UE 200 based on at least one of the following predetermined conditions for determining whether coverage extension (repeated transmission of the PRACH) is necessary:

[0132] Option 1-1: The UE 200 may implicitly determine whether to perform repeated transmission of the PRACH based on the received power (RSRP) of the received SSB. For example, the UE 200 may implicitly determine to perform repeated transmission of the PRACH when the received power of the received SSB is smaller than a threshold (or equal to or smaller than a threshold) (a predetermined condition).

[0133] Option 1-2: The UE 200 may implicitly determine whether to perform repeated transmission of the PRACH based on the RO configuration. For example, the UE 200 may implicitly determine to perform repeated transmission of the PRACH based on one or more of a PRACH configuration index, a PRACH preamble format, the number of ROs in a PRACH slot, the information element "zeroCorrelationZoneConfig," etc. For example, the UE 200 may implicitly determine to perform repeated transmission of the PRACH when a predetermined PRACH configuration index (which implies that repeated transmission of the PRACH is required) is set (a predetermined condition), when a predetermined PRACH preamble format (which implies that repeated transmission of the PRACH is required) is set (specified) (a predetermined condition), and / or when the number of ROs in a PRACH slot is greater than (greater than) a threshold (or is equal to or greater than a threshold) (a predetermined condition). Additionally or alternatively, since the information element “zeroCorrelationZoneConfig” is considered to be an index representing the size of a cell, when the cell is considered to be relatively large based on the value of the information element “zeroCorrelationZoneConfig” (for example, when the value of the information element “zeroCorrelationZoneConfig” is greater than a threshold (or is equal to or greater than the threshold) (predetermined condition), the UE 200 may implicitly decide to perform repeated transmission of the PRACH. The above-mentioned PRACH configuration index, PRACH preamble format, number of ROs in a PRACH slot, information element “zeroCorrelationZoneConfig”, etc. may be referred to as “random access configuration information”, “information related to the configuration of random access”, “random access channel transmission configuration information”, “information related to the configuration of random access channel transmission”, “information related to resources for random access”, “information related to resources for random access channel transmission”, “information related to resources for transmitting the random access channel”, etc. Furthermore, the predetermined condition may be referred to as “condition related to resource configuration for transmitting the random access channel”, etc.

[0134] Option 1-3: UE 200 may implicitly determine whether to perform repeated transmission of the PRACH based on the purpose and / or type of the random access procedure. For example, UE 200 may implicitly determine to perform repeated transmission of the PRACH based on CBRA, CFRA, 4-step RACH, 2-step RACH, random access procedure initiated by PDCCH (order) / MAC (entity) / RRC, random access upon system information request / recovery of beam failure on the SpCell / RRC reconfiguration in a synchronized state, etc. For example, if the random access does not comply with 2-step RACH (predetermined condition), UE 200 may implicitly determine to perform repeated transmission of the PRACH. More generally, for example, if the purpose and / or type of the random access procedure is a predetermined purpose and / or type (predetermined condition), the UE 200 may implicitly decide to perform repeated transmission of the PRACH.

[0135] Option 1-4: The UE 200 may implicitly determine whether to perform repeated transmission of the PRACH based on the RAR window (duration) period (RAR window length) for receiving the RAR. For example, the UE 200 may implicitly determine to perform repeated transmission of the PRACH when the RAR window period is greater than a threshold (or equal to or greater than a threshold) (a predetermined condition). The predetermined condition may be referred to as a "condition regarding a response message for a random access channel" or the like.

[0136] Option 1-5: The UE 200 may implicitly determine whether to perform repeated transmission of the PRACH based on whether the RAR is received within the RAR window. For example, the UE 200 may implicitly determine to perform repeated transmission of the PRACH when the RAR is not received within the RAR window (predetermined condition). The predetermined condition may be referred to as a "condition regarding a response message for a random access channel" or the like.

[0137] In these Options 1-1 to 1-5, the criteria for the decisions in Options 1-1 to 1-2 of the above-mentioned proposal P2-1 and / or the settings, notifications or instructions in Options 2-1 to 2-5 may also be referred to as criteria and / or settings, notifications or instructions that UE200 determines, considers or assumes whether to use additional resources.

[0138] ・Option 2 If UE200 decides to perform repeated transmission of PRACH in Option 1 of proposal P2-2 described above, in Option 2, UE200 may follow a setting, notification or instruction dedicated to repeated transmission of PRACH from gNB100, which may be at least one of the following:

[0139] Option 2-1 The maximum number of PRACH transmissions may be set, notified, or instructed to UE 200 by gNB 100, and UE 200 may repeatedly transmit PRACH based on the maximum number. Note that the maximum number of PRACH transmissions may be set, notified, or instructed to UE 200 by system information such as SIB1, RRC, MAC-CE, and / or DCI.

[0140] Option 2-2: An additional RO or additional resource for the PRACH may be configured, notified, or indicated to the UE 200 by the gNB 100. The UE 200 may repeatedly transmit the PRACH using the additional RO or additional resource. The additional RO or additional resource may be defined, configured, notified, or indicated as proposed in any of the above-mentioned proposals P1-1 to P1-3.

[0141] In these Options 2-1 to 2-2, the criteria for the decisions in Options 1-1 to 1-2 of the above-mentioned proposal P2-1 and / or the settings, notifications or instructions in Options 2-1 to 2-5 may also be referred to as criteria and / or settings, notifications or instructions that UE200 uses to decide, consider or assume whether to use additional resources.

[0142] In proposal P2-2, UE200 may determine whether to perform repeated transmission of PRACH based on predetermined conditions. For example, UE200 may determine to perform repeated transmission of PRACH, assuming that repeated transmission of PRACH is necessary when the above-mentioned predetermined conditions are met. Then, UE200 may repeatedly transmit PRACH to gNB100 in accordance with this determination, in accordance with a configuration, notification, or instruction from gNB100. Specifically, UE200 may repeatedly transmit PRACH to gNB100 based on the maximum number of repeated transmissions of PRACH and / or additional RO or additional resources for repeated transmission of PRACH configured, notified, or instructed by gNB100. The maximum number of repeated transmissions of PRACH and the additional RO or additional resources for repeated transmission of PRACH may be referred to as a configuration, notification, instruction, etc. regarding repeated transmission of PRACH.

[0143] As described above, according to Options 1 and 2 of Proposal P2-2, repeated transmission of the PRACH is performed only when it is assumed that coverage extension (repeated transmission of the PRACH) is necessary based on predetermined conditions, so that unnecessary resource use can be suppressed or avoided, which is advantageous in terms of resource efficiency. Therefore, repeated transmission of the PRACH can be performed appropriately in the random access procedure.

[0144] <Solution 3> Next, a solution to "(1-3) What resources can be used as additional resources for repeated PRACH transmission" will be described.

[0145] [Proposal P3-1] In proposal P3-1, additional resources for repeated transmission of the PRACH may be set (determined) by taking into account a predetermined setting. Specifically, in proposal P3-1, additional resources for repeated transmission of the PRACH may be set by taking into account settings related to other signals and / or channels as a predetermined setting. Note that this setting may be performed by the gNB 100.

[0146] Option 1 In Option 1, the above-mentioned "settings related to other signals and / or channels" may be at least one of the following: "(information indicating) settings related to other signals and / or channels" may be referred to as "setting information for signals and / or channels different from the random access channel," "information related to settings for signals and / or channels different from the random access channel," etc.

[0147] Option 1-1: The "settings related to other signals and / or channels" may be settings related to a symbol configuration in time division duplex (TDD). More specifically, the "settings related to other signals and / or channels" may be the information element "tdd-UL-DL-ConfigurationCommon" and / or the information element "tdd-UL-DL-ConfigurationDedicated." For example, the additional resources for repeated transmission of the PRACH may be configured (determined) so as not to include downlink symbols and / or flexible symbols configured in the information element "tdd-UL-DL-ConfigurationCommon" and / or the information element "tdd-UL-DL-ConfigurationDedicated." In one example, the additional resources for repeated transmission of the PRACH may be configured (determined) so as not to include at least downlink symbols configured in the information element "tdd-UL-DL-ConfigurationCommon" and / or the information element "tdd-UL-DL-ConfigurationDedicated." This makes it possible to avoid overlap with symbols used in the downlink. The information element "tdd-UL-DL-ConfigurationCommon" and the information element "tdd-UL-DL-ConfigurationDedicated" may be referred to as "symbol configuration information", "information related to symbol configuration", etc.

[0148] Option 1-2: The "settings related to other signals and / or channels" may be settings related to SSB symbols. More specifically, the "settings related to other signals and / or channels" may be the information element "ssb-PositionInBurst" in SIB1 and / or the information element "ssb-PositionInBurst" in the information element "ServingCellConfigCommon." For example, the additional resources for repeated transmission of the PRACH may be configured (determined) so as not to include symbols for SSB transmission (which may also be referred to as SSB symbols) configured by the information element "ssb-PositionInBurst" in SIB1 and / or the information element "ssb-PositionInBurst" in the information element "ServingCellConfigCommon." This makes it possible to avoid overlap with SSB symbols used in the downlink. The "ssb-PositionInBurst" in SIB1 and the information element "ssb-PositionInBurst" in the information element "ServingCellConfigCommon" may be referred to as "downlink symbol setting information," "information related to the setting of downlink symbols," "synchronization signal symbol setting information," "information related to the setting of synchronization signal symbols," etc.

[0149] Option 1-3: The above "configuration related to other signals and / or channels" may be configuration related to resources for the initial transmission of the PRACH. More specifically, the above "configuration related to other signals and / or channels" may be ROs for the initial transmission of the PRACH (i.e., ROs according to conventional RO configuration). As an example, additional resources for repeated transmission of the PRACH may be configured (determined) so as not to include ROs configured in accordance with the information element "RACH-ConfigCommon" and / or the information element "RACH-ConfigDedicated." As another example, additional resources for repeated transmission of the PRACH may be configured (determined) so as not to include system frames and / or subframes and / or PRACH slots configured in accordance with the information element "RACH-ConfigCommon" and / or the information element "RACH-ConfigDedicated." This makes it possible to avoid overlap with resources used for the initial transmission. The information element "RACH-ConfigCommon" and the information element "RACH-ConfigDedicated" may also be referred to as "random access configuration information", "information related to the configuration of random access", "random access channel transmission configuration information", "information related to the configuration of random access channel transmission", "information related to resources for random access", "information related to resources for random access channel transmission", "information related to resources for transmitting the random access channel", etc.

[0150] Option 1-4: The "settings related to other signals and / or channels" may be any combination of Options 1-1 to 1-3. For example, the additional resources for repeated transmission of the PRACH may be set (determined) so as not to include downlink symbols and flexible symbols in Option 1-1, and so as not to include SSB symbols (in the case of Option 1-2). In this case, overlap with symbols used in the downlink can be completely avoided.

[0151] Option 2 In Option 2, the additional resources for repeated transmission of the PRACH may be at least one of the following: "(Information indicating) additional resources for repeated transmission of the PRACH" may be referred to as "Configuration information of resources for (repeatedly) transmitting the random access channel that are at least partially different from the resources for initial transmission (first transmission)," "Information regarding configuration of resources for (repeatedly) transmitting the random access channel that are at least partially different from the resources for initial transmission (first transmission)," etc.

[0152] Option 2-1 The above "additional resources for repeated transmission of PRACH" may be ROs that are defined, configured, signaled or indicated as proposed in the above-mentioned proposals P1-1 and P1-2.

[0153] Option 2-2 The above "additional resources for repeated PRACH transmissions" may be resources that are defined, configured, signaled or indicated as proposed in the above-mentioned proposal P1-3.

[0154] In proposal P3-1, UE200 may receive information regarding resources for initial transmission of PRACH (random access configuration information related to a first resource for transmitting a random access channel) from gNB100. UE200 may receive configuration information from gNB100 of resources that are at least partially different from the resources for initial transmission for (repeatedly) transmitting PRACH, configured (by gNB100) based on configuration information of other signals and / or channels different from PRACH. UE200 may then configure (determine) resources for initial transmission of PRACH and resources for repeated transmission of PRACH from this configuration information, transmit PRACH to gNB100 using the resources for initial transmission of PRACH, and transmit PRACH to gNB100 using the resources for repeated transmission of PRACH.

[0155] As described above, according to Options 1 and 2 of Proposal P3-1, the resources for the initial transmission of the PRACH and the resources for the repeated transmission of the PRACH do not at least partially overlap (are different), so that it is possible to suppress or avoid collisions between the initial transmission of the PRACH and the repeated transmission of the PRACH. Therefore, it is possible to appropriately perform repeated transmission of the PRACH in the random access procedure.

[0156] <Solution 4> Next, a solution to the following question will be explained: "(1-4) Whether to increase the number of usable preambles per RO (the number of preambles that can be multiplexed in one RO) without increasing the RO, and if the number of usable preambles is to be increased, how to increase the number of usable preambles."

[0157] [Proposal P4-1] In proposal P4-1, different PRACH preambles may be defined between the initial PRACH transmission and the repeat PRACH transmission, regardless of whether the number of usable preambles per RO is increased. Specifically, in proposal P4-1, different root sequence indices used for root sequence generation may be set (determined or selected) between the initial PRACH transmission and the repeat PRACH transmission. The "root sequence index" may also be referred to as a "root sequence identifier," "root sequence identification information," "base sequence index," "base sequence identifier," "base sequence identification information," etc. Furthermore, the "root sequence index (value)" may also be referred to as a "parameter value used for root sequence generation," "information used for root sequence generation," etc.

[0158] Option 1 In Option 1, different root sequence indices may be set (determined) based on at least one of the following:

[0159] Option 1-1: A difference between an existing (starting logic) root sequence index used for the initial transmission of the PRACH and a (starting logic) root sequence index used for the repeated transmission of the PRACH may be specified, configured, notified, or indicated. UE 200 may determine, calculate, derive, or configure a different (starting logic) root sequence index to be used for the repeated transmission of the PRACH based on the difference and the (starting logic) root sequence index used for the initial transmission of the PRACH (configured, notified, or indicated by gNB 100 using the RRC parameter "prach-RootSequenceIndex"). UE 200 may then randomly configure (determine or select) a PRACH preamble sequence to be used for the repeated transmission of the PRACH based on the (starting logic) root sequence index (more specifically, by deriving starting physical root sequence index u corresponding to starting logical root sequence index i in a table such as that shown in FIG. 14 ), and transmit a PRACH including the configured PRACH preamble sequence to gNB 100.

[0160] Option 1-2: Another (starting logic) root sequence index dedicated to repeated transmission of the PRACH (different from that for the initial transmission of the PRACH) may be designated, configured, notified, or indicated. UE 200 may determine, calculate, derive, or set the other (starting logic) root sequence index as a different (starting logic) root sequence index to be used for repeated transmission of the PRACH. UE 200 may then randomly configure (determine or select) a PRACH preamble sequence to be used for repeated transmission of the PRACH based on the (starting logic) root sequence index, and transmit a PRACH including the configured PRACH preamble sequence to gNB 100.

[0161] Option 2 In Option 2, the difference in Option 1-1 above and / or another different (starting logic) root sequence index in Option 1-2 above may be defined, set, signaled, or indicated according to at least one of the following: Such settings (information) may be referred to as "root sequence (generation) setting information," "information related to the setting of the root sequence (generation)," "random access setting information," "information related to the setting of the random access," "random access channel transmission setting information," "information related to the setting of the random access channel transmission," "information related to resources for random access," "information related to resources for transmitting the random access channel," "information related to resources for transmitting the random access channel," etc.

[0162] Option 2-1: The difference and / or other different (starting logical) root sequence index may be defined in the specification as a fixed value (or set of fixed values).

[0163] Option 2-2 The difference and / or other different (starting logic) root sequence index may be configured, signaled, or indicated to the UE 200 by the gNB 100 in accordance with system information such as SIB1, SIB2, or other RRC such as another RRC. As Option 2-2-1, in one example, the difference between the (starting logic) root sequence index used for the initial transmission of the PRACH and the (starting logic) root sequence index used for the repeated transmission of the PRACH may be configured, signaled, or indicated by the RRC. As Option 2-2-2, in one example, the (starting logic) root sequence index dedicated to the repeated transmission of the PRACH may be configured, signaled, or indicated by the RRC. For example, for Option 2-2-1 and Option 2-2-2, the existing information element "RACH-ConfigCommon" can be extended as shown in FIG. 13. In FIG. 13 , the RRC parameter "prach-RootSequenceIndexDiffForRepetition" represents the difference between the (starting logic) root sequence index used for the initial PRACH transmission and the (starting logic) root sequence index used for the repeated PRACH transmission. Also in FIG. 13 , the RRC parameter "prach-RootSequenceIndexForRepetition" represents the (starting logic) root sequence index dedicated to the repeated PRACH transmission, and the configurable maximum value of these may be set to 1149, matching the maximum value of the RRC parameter "prach-RootSequenceIndex-r16." The parameter "prach-RootSequenceIndexDiffForRepetition" and / or the parameter "prach-RootSequenceIndexForRepetition" may be a single parameter for all PRACH preamble sequence lengths, or may be different parameters for different PRACH preamble sequence lengths. In the latter case, the configurable maximum value may be equal to the corresponding PRACH preamble sequence length. The names of these parameters are merely examples and may be changed as appropriate. Furthermore, the PRACH preamble sequence may be referred to as a PRACH sequence or the like.

[0164] Option 2-3: The difference and / or other different (starting logic) root sequence index may be configured, notified, or indicated by the gNB 100 to the UE 200 in accordance with the MAC-CE and / or DCI. As Option 2-3-1, in one example, the difference between the (starting logic) root sequence index used for the initial transmission of the PRACH and the (starting logic) root sequence index used for the repeated transmission of the PRACH may be configured, notified, or indicated by the MAC-CE. As Option 2-3-2, in one example, the (starting logic) root sequence index dedicated to the repeated transmission of the PRACH may be configured, notified, or indicated by the DCI.

[0165] Option 3 In Option 3, the method of determining the (physical) root sequence (index) (the incremental order of the root sequence index) may be at least one of Options 3-1, 3-1′, and 3-2 described below.

[0166] Option 3-1: The incremental order of root sequence index may reuse the rules of 3GPP Release 15 or 16 (i.e., ascending order of (logical) root sequence index i according to Table 6.3.3.1-3 / 4 / 4A / 4B described in Non-Patent Document 1). This is indicated by the arrow labeled "Opt3-1" in Figure 14, which also shows Table 6.3.3.1-4 described in Non-Patent Document 1.

[0167] Option 3-1′ The incremental order of the root sequence index may be the reverse of Option 3-1 above, that is, the descending order of the (logical) root sequence index i according to Table 6.3.3.1-3 / 4 / 4A / 4B described in Non-Patent Document 1.

[0168] Option 3-2: The incremental order of root sequence indexes may be such that root sequence indexes used in the initial PRACH transmission are not used (e.g., skipped). Therefore, for example, the root sequence index set (determined or selected) as a result of skipping may be incremented or decremented from the (logical) root sequence index originally set for the initial transmission. A combination of Option 3-1 and Option 3-2 is shown by the arrows labeled "Opt3-1 and Opt3-2" in FIG. 14 . In this example, sequence number (physical root sequence index) u=3, which corresponds to (logical) root sequence index i=4 used in the initial PRACH transmission, is skipped, and sequence numbers u=137 and 136, which correspond to (logical) root sequence index i=4 and 5, respectively, are used for repeated PRACH transmissions.

[0169] In proposal P4-1, the UE 200 may receive, as root sequence configuration information from the gNB 100, for example, a first root sequence index value (parameter value) used to generate a first root sequence for an initial transmission (first transmission) of the PRACH, and a second root sequence index value different from the first root sequence index value or a difference with respect to the first root sequence index value, used to generate a second root sequence for a repeated transmission (second transmission) of the PRACH. The UE 200 may set (determine) the first root sequence index value and the second root sequence index value or the difference. The UE 200 may transmit the PRACH to the gNB 100 as an initial transmission based on the first root sequence corresponding to the first root sequence index value, and may transmit the PRACH to the gNB 100 as a repeated transmission based on the second root sequence index value or the difference. More specifically, UE200 may transmit a PRACH including a first PRACH preamble sequence based on a first root sequence corresponding to a first root sequence index value to gNB100 as an initial transmission, and may transmit a PRACH including a second PRACH preamble sequence based on a second root sequence corresponding to a second root sequence index value or the above-mentioned difference to gNB100 as a repeated transmission.

[0170] As described above, according to Options 1 to 3 of Proposal P4-1, the PRACH preamble sequence for repeated transmission of the PRACH is based on a root sequence that is different from the root sequence for the initial transmission of the PRACH, so that it is possible to suppress or avoid collisions between the initial transmission of the PRACH and the repeated transmission of the PRACH. As a result, it is possible to appropriately perform repeated transmission of the PRACH in the random access procedure.

[0171] [Proposal P4-2] In proposal P4-2, different PRACH preambles may be defined between the initial PRACH transmission and the repeated PRACH transmission, regardless of whether the number of usable preambles per RO is increased. Specifically, in proposal P4-2, one or more different cyclic shifts used for root sequence generation may be set (determined or selected) between the initial PRACH transmission and the repeated PRACH transmission. The "cyclic shift (value)" may also be referred to as "parameter value used for root sequence generation," "information used for root sequence generation," etc.

[0172] Option 1 In Option 1, one or more different cyclic shifts may be set (determined) based on at least one of the following:

[0173] Option 1-1: One or more different cyclic shifts may be set (determined) based on a difference between an existing cyclic shift used for the initial transmission of the PRACH and a cyclic shift used for the repeated transmission of the PRACH. That is, one or more cyclic shifts used for the repeated transmission of the PRACH may be shifted based on a conventional cyclic shift (for the initial transmission of the PRACH) defined in the specifications. The UE 200 may determine, calculate, derive, or set a different cyclic shift to be used for the repeated transmission of the PRACH based on the difference and the cyclic shift used for the initial transmission of the PRACH (determined, calculated, derived, or set based on a value set, notified, or indicated by the gNB 100 in the RRC parameter "zeroCorrelationZoneConfig"). Then, the UE 200 may randomly set (determine or select) a PRACH preamble sequence to be used for the repeated transmission of the PRACH based on the cyclic shift, and transmit the PRACH including the set PRACH preamble sequence.

[0174] Option 1-2 One or more different cyclic shifts may be determined (set) based on another cyclic shift dedicated to the repeated transmission of the PRACH (different from that used for the initial transmission of the PRACH). That is, one or more cyclic shifts used for the repeated transmission of the PRACH may be another cyclic shift dedicated to the repeated transmission of the PRACH (different from that used for the initial transmission of the PRACH). The UE 200 may determine, calculate, derive, or set the other cyclic shift as the different cyclic shift to be used for the repeated transmission of the PRACH. Then, the UE 200 may randomly set (determine or select) a PRACH preamble sequence to be used for the repeated transmission of the PRACH based on the cyclic shift, and transmit the PRACH including the set PRACH preamble sequence.

[0175] Option 2 In Option 2, the difference in Option 1-1 above and / or other different cyclic shifts in Option 1-2 above may be defined, configured, notified, or indicated according to at least one of the following: Such configuration (information) may be referred to as "root sequence (generation) configuration information," "information related to the configuration of the root sequence (generation)," "random access configuration information," "information related to the configuration of the random access channel," "random access channel transmission configuration information," "information related to the configuration of the random access channel," "information related to resources for random access," "information related to resources for transmitting the random access channel," "information related to resources for transmitting the random access channel," etc.

[0176] Option 2-1 The difference and / or other different cyclic shifts may be defined as a fixed value (or a set of fixed values) in the specification. In one example, in the case of a difference, the difference in cyclic shift values ​​may be defined for repeated transmission of the PRACH. In another example, in the case of other different cyclic shifts, a set of dedicated cyclic shifts may be defined for repeated transmission of the PRACH. In one example of this Option 2-1 combined with the above Option 1-1, the cyclic shifts may be defined according to the formula shown in bold in the following formula (1), which is an extension of the formula described in "6.3.3.1 Sequence generation" in Non-Patent Document 1. In formula (1), Cv represents a cyclic shift, and N ｃｓ represents how many cyclic shifts can be used in a given root sequence, which is determined based on the value of the information element "zeroCorrelationZoneConfig" described above, diffCS represents the difference from the cyclic shift value, and L ＲＡ represents the PRACH preamble sequence length. Note that the values ​​of v may be in ascending order or descending order.

[0177] Option 2-2 The difference and / or other different cyclic shifts may be configured, notified, or indicated to the UE 200 by the gNB 100 in accordance with RRC such as system information such as SIB1, SIB2, or other RRC. In one example, in the case of a difference, the difference in cyclic shift values ​​may be configured, notified, or indicated for repeated transmission of the PRACH in accordance with the RRC. In another example, in the case of other different cyclic shifts, a dedicated set of cyclic shifts may be configured, notified, or indicated for repeated transmission of the PRACH in accordance with the RRC.

[0178] Option 2-3 The difference and / or other different cyclic shifts may be configured, notified, or indicated by the gNB 100 to the UE 200 according to the MAC-CE and / or DCI. In one example, the difference between the cyclic shift used for the initial transmission of the PRACH and the cyclic shift used for the repeated transmission of the PRACH may be configured, notified, or indicated by the MAC-CE. In another example, a set of cyclic shifts dedicated to the repeated transmission of the PRACH may be configured, notified, or indicated by the DCI.

[0179] In proposal P4-2, the UE 200 may receive, as root sequence configuration information, from the gNB 100, for example, a first cyclic shift value (parameter value) used to generate a first root sequence for an initial transmission (first transmission) of the PRACH, and a second cyclic shift value different from the first cyclic shift value or a difference from the first cyclic shift value used to generate a second root sequence for a repeated transmission (second transmission) of the PRACH. The UE 200 may configure (determine) the first cyclic shift value and the second cyclic shift value or the difference. The UE 200 may transmit the PRACH to the gNB 100 as an initial transmission based on the first root sequence corresponding to the first cyclic shift value, and may transmit the PRACH to the gNB 100 as a repeated transmission based on the second cyclic shift value or the difference. More specifically, UE200 may transmit a PRACH including a first PRACH preamble sequence based on a first root sequence corresponding to a first cyclic shift value to gNB100 as an initial transmission, and may transmit a PRACH including a second PRACH preamble sequence based on a second root sequence corresponding to a second cyclic shift value or the above-mentioned difference to gNB100 as a repeated transmission.

[0180] As described above, according to Options 1 and 2 of Proposal P4-2, the PRACH preamble sequence for repeated transmission of the PRACH is based on a cyclic shift that is different from the cyclic shift for the initial transmission of the PRACH, so that it is possible to suppress or avoid collisions between the initial transmission of the PRACH and the repeated transmission of the PRACH. Therefore, it is possible to appropriately perform repeated transmission of the PRACH in the random access procedure.

[0181] [Proposal P4-3] In proposal P4-3, the number of PRACH preambles available per RO may be increased. The RO may be referred to as a "resource for random access channel" or the like.

[0182] Option 1 In Option 1, the (exact) number of PRACH preambles per RO may be any of the following:

[0183] Option 1-1 The number of PRACH preambles per RO may be fixed to 128 (=64*2). For example, the fixed number of 128 may be defined in the specifications.

[0184] Option 1-2 The number of PRACH preambles per RO may be 64*X (X is an integer equal to or greater than 1). For example, the value X may be fixed and defined in a specification, or may be set, notified, or instructed to the UE 200 by the gNB 100 according to RRC, MAC-CE, and / or DCI. The setting (information) of "value X" may be referred to as "preamble number setting information," "information related to the setting of the number of preambles," "random access setting information," "information related to the setting of random access," "random access channel transmission setting information," "information related to the setting of random access channel transmission," "information related to resources for random access," "information related to resources for random access channel transmission," "information related to resources for transmitting the random access channel," or the like.

[0185] Option 1-3 The number of PRACH preambles per RO may be Y (Y is an integer greater than 64). For example, the value Y may be fixed and defined in the specifications, or may be configured, notified, or instructed to the UE 200 by the gNB 100 according to RRC, MAC-CE, and / or DCI. The setting (information) of "value Y" may be referred to as "preamble number setting information," "information regarding the setting of the number of preambles," "random access setting information," "information regarding the setting of random access," "random access channel transmission setting information," "information regarding the setting of random access channel transmission," "information related to resources for random access," "information related to resources for random access channel transmission," "information related to resources for transmitting the random access channel," or the like.

[0186] Option 2 In Option 2, the new definition of the number of PRACH preambles per RO in Option 1 above may be enabled if at least one of the following is true:

[0187] The new definition of the number of PRACH preambles in Option 2-1 may always be enabled. That is, the gNB 100 (base station) and the UE 200 (terminal) in 3GPP Release 18 may assume without exception that the values ​​proposed in Options 1-1 to 1-3 of Proposal P4-3 above are the number of PRACH preambles per RO.

[0188] Option 2-2 The new definition of the number of PRACH preambles may be enabled according to the configuration. For example, when the gNB 100 configures that PRACH repeat transmission is enabled (turned on), or when the UE 200 receives information indicating such configuration, the gNB 100 and the UE 200 may assume that the value proposed in Options 1-1 to 1-3 of the above-mentioned proposal P4-3 is the number of PRACH preambles per RO. Conversely, when the gNB 100 configures that PRACH repeat transmission is not enabled (turned off), or when the UE 200 receives information indicating such configuration, the gNB 100 and the UE 200 may assume that the number of PRACH preambles per RO is 64.

[0189] Option 2-3: The new definition of the number of PRACH preambles may be enabled when a predetermined condition is met or not met. For example, if the SSB associated with the PRACH (or the RO) that the UE is attempting to transmit is received at a received power (RSRP) lower than (or equal to or lower than) a threshold, the UE 200 may assume that the values ​​proposed in Options 1-1 to 1-3 of the above-mentioned proposal P4-3 are the number of PRACH preambles per RO. On the other hand, in this case, the gNB 100 may assume without exception that the values ​​proposed in Options 1-1 to 1-3 of the above-mentioned proposal P4-3 are the number of PRACH preambles per RO, as in the above-mentioned Option 2-1.

[0190] In proposal P4-3, UE200 may receive, for example, "value X" or "value Y" from gNB100 as preamble number setting information. UE200 may set (determine) the number of PRACH preambles available per RO (resource for random access channel) based on, for example, "value X" or "value Y." This number may exceed 64. UE200 may randomly set (determine or select) a first PRACH preamble for an initial transmission (first transmission) of the PRACH from among the available PRACH preambles, and may randomly set (determine or select) a second PRACH preamble for a repeated transmission (second transmission) of the PRACH. Then, UE200 may transmit a PRACH including the set first PRACH preamble as a first transmission, and transmit a PRACH including the set second PRACH preamble as a second transmission.

[0191] As described above, according to Options 1 and 2 of Proposal P4-3, the number of PRACH preambles for PRACH transmission (initial transmission and repeated transmission) is increased compared to the number of PRACH preambles for conventional PRACH transmission, and the PRACH preambles randomly set (determined) for the initial PRACH transmission and the repeated PRACH transmission are likely to be different, making it possible to suppress or avoid collisions between the initial PRACH transmission and the repeated PRACH transmission. Thus, the repeated PRACH transmission can be performed appropriately in the random access procedure.

[0192] <Solution 5> Next, a solution to "(1-5) Whether to explicitly suppress or avoid collisions between initial PRACH transmissions and repeated PRACH transmissions within an existing (same) RO, and if collisions are explicitly suppressed or avoided, how to explicitly suppress or avoid collisions" will be described.

[0193] [Proposal P5-1] In proposal P5-1, a PRACH preamble group may be introduced so that a PRACH preamble for an initial transmission of a PRACH and a PRACH preamble for repeated transmissions of a PRACH are defined separately.

[0194] Option 1 In Option 1, a new group for initial transmission of the PRACH and a new group for repeated transmission of the PRACH may be defined as follows:

[0195] Option 1-1: A setting may be made for one group so as to group existing groups A and B, which are grouped according to the size (amount of data) of Msg3. More specifically, the number of PRACH preamble indices for the initial transmission of the PRACH (or repeated transmission of the PRACH) may be set for one group by the gNB 100 and set, notified, or instructed to the UE 200 by the gNB 100. The other group may be determined, calculated, derived, or set by the UE 200 by subtracting the above-mentioned number of PRACH preamble indices from the number of PRACH preamble indices per RO (64). In this case, since only the number of PRACH preamble indices for one group is notified to the UE 200, an increase in the amount of signaling can be suppressed. The "preamble index" may also be referred to as "preamble identification information," "preamble identifier," or the like. The setting (information) of the "number of PRACH preamble indices" may be referred to as "preamble (index) number setting information," "information related to the setting of the number of preambles (indexes)," "random access setting information," "information related to the setting of random access," "random access channel transmission setting information," "information related to the setting of random access channel transmission," "information related to resources for random access," "information related to resources for transmitting the random access channel," etc. Note that the number of groups is not limited to two, and one group may exist for each transmission in repeated transmission as long as no contradiction occurs with the existing groups A and B.

[0196] Option 1-2 The number of PRACH preamble indexes that can be used for repeated PRACH transmission may be explicitly set. This setting may be in accordance with RRC, MAC-CE, and / or DCI. For example, the number of PRACH preamble indexes M may be set by the gNB 100 for repeated PRACH transmission (a group for repeated PRACH transmission), and may be set, notified, or instructed by the gNB 100 to the UE 200. The setting (information) of the "value M" may be referred to as "preamble (index) number setting information," "information regarding the setting of the number of preambles (indexes)," "random access setting information," "information regarding the setting of random access," "random access channel transmission setting information," "information regarding the setting of random access channel transmission," "information related to resources for random access," "information related to resources for random access channel transmission," "information related to resources for transmitting the random access channel," or the like.

[0197] Option 2 In Option 2, the definitions of the existing groups A and B described above may be reused.

[0198] Option 2-1: The configuration of PRACH preamble indices used for the initial transmission of the PRACH and the repeated transmission of the PRACH may be considered for group A and / or group B. For example, as shown in FIG. 15 , each of groups A and B may be divided into an index for the initial transmission of the PRACH and an index for the repeated transmission of the PRACH. In the example shown in FIG. 15 , PRACH preamble indices 0 to X included in group A may be used for the initial transmission of the PRACH, and PRACH preamble indices (X+1) to Y included in group A may be used for the repeated transmission of the PRACH. Similarly, PRACH preamble indices (Y+1) to (Y+X+1) included in group B may be used for the initial transmission of the PRACH, and PRACH preamble indices (Y+X+2) to 63 included in group B may be used for the repeated transmission of the PRACH. Note that the value Y may be set, notified, or indicated as in the conventional manner. In this case, the values ​​X and Y may be determined so that the number of PRACH preamble indexes used for the initial transmission of the PRACH in groups A and B and the number of PRACH preamble indexes used for repeated transmission of the PRACH are each less than both the PRACH preamble indexes included in group A and the PRACH preamble indexes included in group B. The value X may be fixed and defined in the specifications, or may be configured, notified, or indicated to the UE 200 by the gNB 100 according to RRC, MAC-CE, and / or DCI. The settings (information) of "value X" and "value Y" may be referred to as "preamble (index) number setting information," "information related to the setting of the number of preambles (indexes)," "random access setting information," "information related to the setting of random access," "random access channel transmission setting information," "information related to the setting of random access channel transmission," "information related to resources for random access," "information related to resources for random access channel transmission," "information related to resources for transmitting the random access channel," or the like.In the example shown in FIG. 15, the PRACH preamble indices used for the initial transmission of the PRACH (or repeated transmission of the PRACH) are allocated consecutively within the group, but in other examples, the PRACH preamble indices may be allocated non-consecutively within the group.

[0199] In proposal P5-1, UE 200 may receive, for example, "value M," "value X," and / or "value Y" from gNB 100 as preamble number setting information. UE 200 may set (determine or select) a first PRACH preamble index for the initial transmission of the PRACH from a first group including a first number (e.g., M or (X+1)) of PRACH preamble indexes (identifiers) for the initial transmission (first transmission) of the PRACH from among a first specific number (e.g., 64 or (Y+1)) of PRACH preamble indexes. UE 200 may set (determine or select) a second PRACH preamble index for the repeated transmission of the PRACH from a second group including a second number of PRACH preamble indexes obtained by subtracting the first number from the first specific number for the repeated transmission (second transmission) of the PRACH. Then, the UE 200 may transmit the PRACH to the gNB 100 as an initial transmission based on the set first PRACH preamble index, and may transmit the PRACH to the gNB 100 as a repeated transmission based on the set second PRACH preamble index. More specifically, the UE 200 may transmit the PRACH including the first PRACH preamble corresponding to the set first PRACH preamble index to the gNB 100 as an initial transmission, and may transmit the PRACH including the second PRACH preamble corresponding to the set second PRACH preamble index to the gNB 100 as a repeated transmission.

[0200] Furthermore, in proposal P5-1, the first group and the second group may be divided from a predefined group A (third group) including a third number (e.g., (Y+1)) of PRACH preamble indexes (identifiers) out of a second specific number (e.g., 64), or may be divided from a predefined group B (fourth group) including a fourth number of PRACH preamble indexes obtained by subtracting the third number from the second specific number.

[0201] As described above, according to Options 1 and 2 of Proposal P5-1, the PRACH preamble group for the initial transmission of the PRACH and the PRACH preamble group for the repeated transmission of the PRACH are distinguished, and the PRACH preamble index used for the repeated transmission of the PRACH is different from the PRACH preamble index used for the initial transmission of the PRACH. Therefore, even when using existing RO, collisions between the initial transmission of the PRACH and the repeated transmission of the PRACH can be suppressed or avoided. Therefore, the repeated transmission of the PRACH can be appropriately performed in the random access procedure. Furthermore, according to Options 1 and 2 of Proposal P5-1, additional resources for the repeated transmission of the PRACH are not used, so the load and resource efficiency of the gNB that blind decodes the PRACH can be maintained as before.

[0202] [Proposal P5-2] In Proposal P5-2, an association period within a predetermined duration may be divided into multiple groups so that initial PRACH transmissions and repeat PRACH transmissions occur in different association periods. An "association period" may also be referred to as a "period for random access channel (or) transmission," a "period for random access channel (or) transmission," a "period including at least one RO corresponding to all SSB beams being transmitted," etc.

[0203] Option 1 In Option 1, the above-mentioned "predetermined duration" may be defined, set, notified, or indicated as at least one of the following. The setting (information) of the "predetermined duration" may be referred to as "random access transmission period setting information," "information related to the setting of the random access transmission period," "random access setting information," "information related to the setting of the random access," "random access channel transmission setting information," "information related to the setting of the random access channel transmission," "information related to resources for random access," "information related to resources for random access channel transmission," "information related to resources for transmitting the random access channel," etc.

[0204] Option 1-1 The above "predetermined duration" may be defined, set, notified or indicated as an SSB period (for example, 20 milliseconds).

[0205] Option 1-2 The above "predetermined duration" may be defined, configured, signaled or indicated as 160 ms, or more generally as the maximum period (maximum value) of the SSB burst and PRACH configuration period.

[0206] Option 1-3: The above-mentioned "predetermined duration" may be defined, set, notified or indicated as a multiple of the SSB period (an integer multiple of 2 or more).

[0207] Option 1-4 The above "predetermined duration" may be defined, configured, signaled, or indicated as 160 milliseconds, or more generally as a multiple (an integer multiple of 2 or greater) of the maximum period (maximum value) of the SSB burst and PRACH configuration period.

[0208] The above SSB period, maximum period and multiple may be fixed and defined in the specifications, or may be set, notified or instructed to UE200 by gNB100 in accordance with RRC, MAC-CE and / or DCI.

[0209] Option 2 In Option 2, the exact period for the initial transmission of PRACH and the exact period for the repeated transmission of PRACH may be defined based on any of the following:

[0210] Option 2-1 The first X association periods may be for initial transmission of the PRACH, and the next X association periods may be for repeated transmission of the PRACH, and this cycle of 2X association periods may be repeated. The value X or 2X may be fixed and defined in the specifications, or may be configured, notified, or indicated to the UE 200 by the gNB 100 according to RRC, MAC-CE, and / or DCI. The settings (information) of "value X" and "value 2X" may be referred to as "random access transmission period setting information," "information regarding the setting of the random access transmission period," "random access setting information," "information regarding the setting of random access," "random access channel transmission setting information," "information regarding the setting of random access channel transmission," "information related to resources for random access," "information related to resources for random access channel transmission," "information related to resources for transmitting the random access channel," or the like.

[0211] Option 2-2 The association period for the initial transmission of the PRACH may be located anywhere within a predetermined duration, and the association period for the repeated transmission of the PRACH may be restricted to be located in the first half, second half, or a specific defined range within the predetermined duration.

[0212] In proposal P5-2, the UE 200 may receive, for example, a "predetermined duration," "value X," and / or "value 2X" as random access transmission period setting information from the gNB 100. The UE 200 may set (determine), for example, a first association period (period) for the initial transmission (first transmission) of the PRACH and a second association period (period) for repeated transmission (second transmission) of the PRACH, which is different from the first association period, within a predetermined (duration) period based on the random access transmission period setting information. More specifically, the UE 200 may set (determine) the first association period and the second association period, for example, so that the first X first association periods and the next X second association periods are repeated for a predetermined duration. Then, the UE 200 may transmit the PRACH to the gNB 100 as an initial transmission in the set first association period, and may transmit the PRACH to the gNB 100 as a repeated transmission in the set second association period.

[0213] As described above, according to Options 1 and 2 of Proposal P5-2, the initial transmission of the PRACH and the repeated transmission of the PRACH are performed in different association periods, so that even when using existing RO, it is possible to suppress or avoid collisions between the initial transmission of the PRACH and the repeated transmission of the PRACH. Therefore, the repeated transmission of the PRACH can be performed appropriately in the random access procedure. Furthermore, according to Options 1 and 2 of Proposal P5-2, additional resources for the repeated transmission of the PRACH are not used, so the load and resource efficiency of the gNB that blind decodes the PRACH can be maintained as before.

[0214] <Definition of PRACH initial transmission and PRACH repeat transmission> In the above, the terms PRACH initial transmission and PRACH repeat transmission are used, but PRACH initial transmission and PRACH repeat transmission may mean any of the following.

[0215] Option 1 In Option 1, both the initial transmission of PRACH and the repeated transmission of PRACH may mean PRACH transmission before UE 200 receives RAR (Msg2) (i.e., before the opportunity to receive RAR (Msg2)).

[0216] Option 2 In Option 2, the initial transmission of the PRACH may mean the PRACH transmission before the UE 200 receives the RAR (Msg2), and the repeated transmission of the PRACH may mean any of the following.

[0217] Option 2-1 Repeated transmission of PRACH may be PRACH transmission after blind decoding of at least one RAR (Msg2), and may be executable only if the RAR (Msg2) has not been decoded by UE200.

[0218] Option 2-2 Repeated transmission of PRACH may be PRACH transmission after blind decoding of at least one RAR (Msg2), and may be executable both when the RAR (Msg2) is not decoded by UE200 and when the RAR (Msg2) is decoded by UE200.

[0219] <UE capability> UE200 may report to gNB100 as UE capability whether it supports the above-mentioned proposals P1 to P5.

[0220] (Device Configuration) Next, a functional configuration example of the gNB100 and UE200 that execute the processes and operations described above will be described. The gNB100 and UE200 may have the functions to implement the above-described embodiments. However, the gNB100 and UE200 may each have only a part of the functions of the embodiments.

[0221] <gNB (Base Station)> Figure 16 is a block diagram showing an example of the configuration of a gNB (base station) 100 according to an embodiment of the present disclosure. The gNB includes, for example, a transmitting unit 101, a receiving unit 102, and a control unit 103. The gNB 100 communicates with a UE 200 (see Figure 17) wirelessly.

[0222] The transmitter 101 transmits a DL signal to the UE 200. For example, the transmitter 101 transmits the DL signal under the control of the controller 103.

[0223] For example, the transmitting unit 101 transmits, as DL signals, various control signals (such as a control signal of an RRC layer), a reference signal, a data signal, and the like to the UE 200. For example, the transmitting unit 101 transmits, as DL signals, various signals, channels, setting information, control information, and the like described in the above embodiments to the UE 200.

[0224] For example, the DL signal may include information indicating scheduling regarding signal transmission of UE 200 (e.g., uplink grant), control information of higher layers, etc.

[0225] The receiving unit 102 receives the UL signal transmitted from the UE 200. For example, the receiving unit 102 receives the UL signal under the control of the control unit 103.

[0226] For example, the receiving unit 102 receives, as an UL signal, a signal including information on the processing capability of the UE 200 (for example, UE capability), various control signals, reference signals, data signals, etc. from the UE 200. For example, the receiving unit 102 receives, as an UL signal, a PRACH.

[0227] The control unit 103 controls the overall (communication) operation of the gNB 100, including the transmission processing in the transmission unit 101 and the reception processing in the reception unit 102.

[0228] For example, the control unit 103 acquires information such as data and control information from the upper layer and outputs it to the transmitting unit 101. The control unit 103 also outputs the data, control information, etc. received from the receiving unit 102 to the upper layer.

[0229] The control unit 103 performs operations other than the transmission and reception described in the above embodiment. Note that these operations may be performed by the transmission unit 101 and / or the reception unit 102.

[0230] <UE (Terminal)> Figure 17 is a block diagram showing an example of the configuration of UE (Terminal) 200 according to one embodiment of the present disclosure. UE 200 includes, for example, a receiving unit 201, a transmitting unit 202, and a control unit 203. UE 200 communicates with, for example, gNB 100 (see Figure 16) wirelessly.

[0231] The receiving unit 201 receives a DL signal transmitted from the gNB 100. For example, the receiving unit 201 receives the DL signal under the control of the control unit 203.

[0232] For example, the receiving unit 201 receives, as DL signals, various control signals, reference signals, data signals, etc. from the gNB 100. The receiving unit 201 receives, as DL signals, various signals, channels, setting information, control information, etc. described in the above embodiments from the gNB 100.

[0233] The transmitting unit 202 transmits the UL signal to the gNB 100. For example, the transmitting unit 202 transmits the UL signal under the control of the control unit 203.

[0234] For example, the transmitting unit 202 transmits, as an UL signal, a signal including information regarding the processing capability of the UE 200, various control signals, reference signals, data signals, etc. to the gNB 100. The transmitting unit 202 transmits, for example, a PRACH to the gNB 100.

[0235] The control unit 203 controls the overall (communication) operation of the UE 200 , including the reception processing in the reception unit 201 and the transmission processing in the transmission unit 202 .

[0236] For example, the control unit 203 acquires information such as data and control information from the upper layer and outputs it to the transmitting unit 202. Also, the control unit 203 outputs, for example, the data and control information received from the receiving unit 201 to the upper layer.

[0237] The control unit 203 performs operations other than the transmission and reception described in the above embodiment. Note that these operations may be performed by the receiving unit 201 and / or the transmitting unit 202.

[0238] Furthermore, the channels used for transmitting DL signals and UL signals are not limited to the above examples, and may include the above-mentioned RACH and PBCH, for example.

[0239] <Hardware Configuration, etc.> 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 also be realized by combining software with the single device or the multiple devices.

[0240] Functions include, but are not limited to, judgment, determination, assessment, calculation, computation, processing, derivation, investigation, search, confirmation, reception, transmission, output, access, resolution, selection, selection, establishment, comparison, assumption, expectation, consideration, broadcasting, notifying, communicating, forwarding, configuring, reconfiguring, allocating, mapping, and assignment. For example, a functional block (component) that performs transmission is called a transmitting unit or transmitter. As mentioned above, there are no particular limitations on how these functions are implemented.

[0241] For example, the gNB 100, UE 200, etc. in one embodiment of the present disclosure may function as a computer that performs processing of the wireless communication method of the present disclosure. Figure 18 is a diagram showing an example of the hardware configuration of the gNB 100 and UE 200 according to an embodiment of the present disclosure. The above-mentioned gNB 100 and UE 200 may be physically configured as a computer device including a processor 1001, memory 1002, storage 1003, communication device 1004, input device 1005, output device 1006, bus 1007, etc.

[0242] In the following description, the term "apparatus" can be replaced with circuit, device, unit, etc. The hardware configuration of the gNB 100 and the UE 200 may be configured to include one or more of the devices shown in the figure, or may be configured without including some of the devices.

[0243] Each function in gNB100 and UE200 is realized by loading specified software (programs) onto hardware such as processor 1001 and memory 1002, causing processor 1001 to perform calculations, control communication by communication device 1004, and control at least one of reading and writing data in memory 1002 and storage 1003.

[0244] The processor 1001 controls the entire computer by running, for example, an operating system. The processor 1001 may be configured by a central processing unit (CPU) including an interface with peripheral devices, a control device, an arithmetic unit, a register, etc. For example, the above-mentioned control units 103, 203, etc. may be realized by the processor 1001.

[0245] In addition, the processor 1001 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 program used is a program that causes a computer to execute at least some of the operations described in the above-described embodiments. For example, the control unit 103 of the gNB 100 and the control unit 203 of the UE 200 may be implemented by a control program stored in the memory 1002 and running on the processor 1001, and similar implementations may be made for other functional blocks. While the above-described various processes have been described as being executed by one processor 1001, they may also be executed simultaneously or sequentially by two or more processors 1001. The processor 1001 may be implemented by one or more chips. The program may be transmitted from a network via a telecommunications line.

[0246] The memory 1002 is a computer-readable recording medium and may be configured by, for example, at least one of a read-only memory (ROM), an erasable programmable ROM (EPROM), an electrically erasable programmable ROM (EEPROM), a random access memory (RAM), etc. The memory 1002 may also be called a register, a cache, a main memory (primary storage device), etc. The memory 1002 can store executable programs (program codes), software modules, etc. for implementing a wireless communication method according to an embodiment of the present disclosure.

[0247] Storage 1003 is a computer-readable recording medium, and may be composed of at least one of, for example, an optical disk such as a CD-ROM (Compact Disc ROM), a hard disk drive, a flexible disk, a magneto-optical disk (e.g., a compact disk, a digital versatile disk, a Blu-ray (registered trademark) disk), a smart card, a flash memory (e.g., a card, a stick, a key drive), a floppy (registered trademark) disk, a magnetic strip, etc. Storage 1003 may also be referred to as an auxiliary storage device. The above-mentioned storage medium may be, for example, a database, a server, or other appropriate medium including at least one of memory 1002 and storage 1003.

[0248] 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 transmitter 101, receiver 102, receiver 201, and transmitter 202 may be realized by the communication device 1004. The communication device 1004 may be implemented with the transmitter and receiver physically or logically separated.

[0249] The input device 1005 is an input device (e.g., a keyboard, a mouse, a microphone, a switch, a button, a sensor, etc.) that receives input from the outside. The output device 1006 is an output device (e.g., a display, a speaker, an 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).

[0250] 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.

[0251] In addition, the gNB 100 and the UE 200 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 by the hardware. For example, the processor 1001 may be implemented using at least one of these pieces of hardware.

[0252] Fig. 19 shows an example configuration of a vehicle 2001. As shown in Fig. 19, the vehicle 2001 includes a drive unit 2002, a steering unit 2003, an accelerator pedal 2004, a brake pedal 2005, a shift lever 2006, front wheels 2007, rear wheels 2008, an axle 2009, an electronic control unit 2010, various sensors 2021 to 2029, an information service unit 2012, and a communication module 2013. Each aspect / embodiment described in the present disclosure may be applied to a communication device mounted on the vehicle 2001, and may be applied to the communication module 2013, for example.

[0253] The drive unit 2002 is configured, for example, by an engine, a motor, or a hybrid of an engine and a motor. The steering unit 2003 includes at least a steering wheel (also called a handle) and is configured to steer at least one of the front wheels and the rear wheels based on the operation of the steering wheel operated by the user.

[0254] The electronic control unit 2010 is composed of a microprocessor 2031, memory (ROM, RAM) 2032, and a communication port (IO port) 2033. Signals are input to the electronic control unit 2010 from various sensors 2021 to 2029 provided in the vehicle 2001. The electronic control unit 2010 may also be called an ECU (Electronic Control Unit).

[0255] The signals from the various sensors 2021 to 2029 include a current signal from a current sensor 2021 that senses the current of the motor, a rotation speed signal of the front and rear wheels obtained by a rotation speed sensor 2022, an air pressure signal of the front and rear wheels obtained by an air pressure sensor 2023, a vehicle speed signal obtained by a vehicle speed sensor 2024, an acceleration signal obtained by an acceleration sensor 2025, an accelerator pedal depression amount signal obtained by an accelerator pedal sensor 2029, a brake pedal depression amount signal obtained by a brake pedal sensor 2026, a shift lever operation signal obtained by a shift lever sensor 2027, and a detection signal for detecting obstacles, vehicles, pedestrians, etc. obtained by an object detection sensor 2028.

[0256] The information service unit 2012 is composed of various devices, such as a car navigation system, an audio system, speakers, a television, and a radio, for providing various types of information such as driving information, traffic information, and entertainment information, and one or more ECUs for controlling these devices. The information service unit 2012 provides various types of multimedia information and multimedia services to the occupants of the vehicle 2001 by using information acquired from external devices via the communication module 2013, etc.

[0257] The driving assistance system unit 2030 is composed of various devices that provide functions for preventing accidents and reducing the driving burden on the driver, such as millimeter-wave radar, LiDAR (Light Detection and Ranging), cameras, positioning locators (e.g., GNSS, etc.), map information (e.g., high-definition (HD) maps, autonomous vehicle (AV) maps, etc.), gyro systems (e.g., IMU (Inertial Measurement Unit), INS (Inertial Navigation System), etc.), AI (Artificial Intelligence) chips, and AI processors, as well as one or more ECUs that control these devices. In addition, the driving assistance system unit 2030 transmits and receives various information via the communication module 2013 to realize the driving assistance function or the autonomous driving function.

[0258] The communication module 2013 can communicate with the microprocessor 2031 and components of the vehicle 2001 via the communication port. For example, the communication module 2013 transmits and receives data via the communication port 2033 to and from the drive unit 2002, steering unit 2003, accelerator pedal 2004, brake pedal 2005, shift lever 2006, front wheels 2007, rear wheels 2008, axle 2009, microprocessor 2031 and memory (ROM, RAM) 2032 in the electronic control unit 2010, and sensors 2021 to 29, which are provided in the vehicle 2001.

[0259] The communication module 2013 is a communication device that can be controlled by the microprocessor 2031 of the electronic control unit 2010 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 2013 may be located either inside or outside the electronic control unit 2010. The external device may be, for example, a base station, a mobile station, or the like.

[0260] The communication module 2013 transmits, via wireless communication to an external device, a current signal from the current sensor that is input to the electronic control unit 2010. The communication module 2013 also transmits, via wireless communication to an external device, the rotation speed signals of the front and rear wheels acquired by a rotation speed sensor 2022, the air pressure signals of the front and rear wheels acquired by an air pressure sensor 2023, the vehicle speed signal acquired by a vehicle speed sensor 2024, the acceleration signal acquired by an acceleration sensor 2025, the accelerator pedal depression amount signal acquired by an accelerator pedal sensor 2029, the brake pedal depression amount signal acquired by a brake pedal sensor 2026, the shift lever operation signal acquired by a shift lever sensor 2027, and detection signals for detecting obstacles, vehicles, pedestrians, etc. acquired by an object detection sensor 2028, all of which are input to the electronic control unit 2010.

[0261] The communication module 2013 receives various information (traffic information, traffic signal information, vehicle distance information, etc.) transmitted from external devices and displays it on the information service unit 2012 provided in the vehicle 2001. The communication module 2013 also stores the various information received from the external devices in a memory 2032 that can be used by the microprocessor 2031. Based on the information stored in the memory 2032, the microprocessor 2031 may control the drive unit 2002, steering unit 2003, accelerator pedal 2004, brake pedal 2005, shift lever 2006, front wheels 2007, rear wheels 2008, axles 2009, sensors 2021 to 2029, etc. provided in the vehicle 2001.

[0262] (Modification) In the above-described embodiment, the operation related to the random access procedure etc. has been described using SSB as an example, but the present disclosure is not limited to this. For example, CSI-RS may be used instead of SSB.

[0263] (Summary of Embodiments) <Resolution 1> According to an embodiment of the present disclosure, there is provided a terminal including: a control unit that sets first information related to a first resource for transmitting a random access channel, and sets second information related to a second resource for transmitting the random access channel, the second resource being at least partially different from the first resource; and a transmission unit that transmits the random access channel to a base station using the first resource based on the first information, and transmits the random access channel to the base station using the second resource based on the second information.

[0264] With the above configuration, since the first resource for a certain transmission of the random access channel and the second resource for another transmission of the random access channel are at least partially different, it is possible to suppress or avoid collisions between a certain transmission of the random access channel and another transmission of the random access channel, thereby enabling appropriate repeated transmission of the random access channel in the random access procedure.

[0265] In the terminal, when there are a plurality of pieces of the second information, the transmitter transmits the random access channel a plurality of times using the second resources corresponding to each of the plurality of pieces of the second information.

[0266] The above configuration allows flexible settings to be made for each of the multiple transmissions of the random access channel.

[0267] In the terminal, when one piece of the second information exists, the transmitter transmits the random access channel a plurality of times using the second resource corresponding to the one piece of the second information.

[0268] The above configuration makes it possible to suppress an increase in the amount of signaling related to settings for multiple transmissions of the random access channel.

[0269] In this terminal, the first resource includes a first system frame for transmitting the random access channel, a first subframe within the first system frame, and a first slot within the first subframe, and the second resource includes a second system frame for transmitting the random access channel, a second subframe within the second system frame, and a second slot within the second system frame, and at least one of the first system frame, the first subframe, and the first slot differs from at least one of the corresponding second system frame, the second subframe, and the second slot in system frame number, subframe number, and slot number.

[0270] With the above configuration, the first resource for a certain transmission of the random access channel can be excluded as the second resource for other transmission.

[0271] In this terminal, the first resource is completely different from the second resource.

[0272] The above configuration makes it possible to avoid collisions between one transmission on the random access channel and another transmission on the random access channel.

[0273] Furthermore, according to an embodiment of the present disclosure, there is provided a communication method in which a terminal configures first information related to a first resource for transmitting a random access channel, configures second information related to a second resource for transmitting the random access channel, the second resource being at least partially different from the first resource, transmits the random access channel to a base station using the first resource based on the first information, and transmits the random access channel to the base station using the second resource based on the second information.

[0274] With the above configuration, since the first resource for a certain transmission of the random access channel and the second resource for another transmission of the random access channel are at least partially different, it is possible to suppress or avoid collisions between a certain transmission of the random access channel and another transmission of the random access channel, thereby enabling appropriate repeated transmission of the random access channel in the random access procedure.

[0275] <Regarding Solution 2> According to an embodiment of the present disclosure, there is provided a terminal including: a control unit that determines to repeatedly transmit a random access channel when a condition is satisfied, assuming that repeated transmission of the random access channel is necessary; and a transmission unit that, in response to the determination, repeatedly transmits the random access channel to a base station in accordance with a setting from the base station regarding repeated transmission of the random access channel.

[0276] With the above configuration, repeated transmission of the random access channel is performed only when it is assumed that repeated transmission of the random access channel is necessary based on the conditions, so that unnecessary resource usage can be suppressed or avoided, which is advantageous in terms of resource efficiency. Therefore, repeated transmission of the random access channel can be performed appropriately in the random access procedure.

[0277] The terminal further includes a receiving unit that receives a synchronization signal or a reference signal from the base station, and the condition is that the received power of the synchronization signal or the reference signal is smaller than a threshold value.

[0278] With the above configuration, it is possible to repeatedly transmit the random access channel when the communication quality is expected to be poor.

[0279] In this terminal, the condition is that specific random access setting information is set and / or that the specific random access setting information is greater than a threshold value.

[0280] The above configuration enables repeated transmission of the random access channel in the case of a specific setting related to the random access procedure that is expected to require repeated transmission of the random access channel.

[0281] In this terminal, the condition is that the purpose and / or type of the random access procedure is a specific purpose and / or type.

[0282] The above configuration allows repeated transmission of the random access channel for a specific purpose and / or type of random access procedure that is expected to require repeated transmission of the random access channel.

[0283] In this terminal, the condition is that the period for receiving a response message for the random access channel is greater than a threshold, and / or that the terminal does not receive the response message within the period.

[0284] The above configuration enables repeated transmission of the random access channel in the case of specific settings related to the random access procedure (specifically, Msg2) that are expected to require repeated transmission of the random access channel and / or in the case where communication quality is expected to be poor.

[0285] Furthermore, according to an embodiment of the present disclosure, a communication method is provided in which a terminal determines to repeatedly transmit a random access channel when a condition is met, assuming that repeated transmission of the random access channel is necessary, and in response to the determination, repeatedly transmits the random access channel to a base station in accordance with a setting from the base station regarding repeated transmission of the random access channel.

[0286] With the above configuration, repeated transmission of the random access channel is performed only when it is assumed that repeated transmission of the random access channel is necessary based on the conditions, so that unnecessary resource usage can be suppressed or avoided, which is advantageous in terms of resource efficiency. Therefore, repeated transmission of the random access channel can be performed appropriately in the random access procedure.

[0287] <Regarding Solution 3> According to an embodiment of the present disclosure, there is provided a terminal including: a receiver that receives, from a base station, random access configuration information related to a first resource for transmitting a random access channel; and configuration information of a second resource for transmitting the random access channel, the second resource being at least partially different from the first resource and configured based on configuration information of a signal and / or channel different from the random access channel; and a transmitter that transmits the random access channel to the base station using the first resource and transmits the random access channel to the base station using the second resource.

[0288] With the above configuration, since the first resource for a certain transmission of the random access channel and the second resource for another transmission of the random access channel are at least partially different, it is possible to suppress or avoid collisions between a certain transmission of the random access channel and another transmission of the random access channel, thereby enabling appropriate repeated transmission of the random access channel in the random access procedure.

[0289] In this terminal, the configuration information of signals and / or channels different from the random access channel includes symbol configuration information, downlink symbol configuration information and / or the random access configuration information.

[0290] With the above configuration, the resources to be used as the second resources can be set taking into consideration the symbols used in the uplink and downlink and / or the resources used for certain transmissions of the random access channel.

[0291] In the terminal, the second resources do not include the downlink symbols set by the symbol setting information.

[0292] The above configuration makes it possible to avoid overlap between the second resource and symbols used in the downlink.

[0293] In the terminal, the second resources do not include flexible symbols set by the symbol configuration information and / or synchronization signal block symbols set by the downlink symbol configuration information.

[0294] The above configuration makes it possible to avoid overlapping of the second resource with flexible symbols (symbols that can be used in the downlink) and / or SSB symbols.

[0295] In the terminal, the second resources do not include system frames and / or subframes and / or slots configured by the random access configuration information.

[0296] The above configuration makes it possible to avoid overlap between the second resource and the first resource.

[0297] Furthermore, according to an embodiment of the present disclosure, there is provided a communication method in which a terminal receives, from a base station, random access configuration information related to a first resource for transmitting a random access channel and configuration information of a second resource for transmitting the random access channel, the second resource being at least partially different from the first resource and configured based on configuration information of a signal and / or channel different from the random access channel, and transmits the random access channel to the base station using the first resource and transmits the random access channel to the base station using the second resource.

[0298] With the above configuration, since the first resource for a certain transmission of the random access channel and the second resource for another transmission of the random access channel are at least partially different, it is possible to suppress or avoid collisions between a certain transmission of the random access channel and another transmission of the random access channel, thereby enabling appropriate repeated transmission of the random access channel in the random access procedure.

[0299] <Regarding Solution 4> According to an embodiment of the present disclosure, there is provided a terminal including: a controller that sets a first parameter value used to generate a first root sequence for a first transmission of a random access channel; and a second parameter value different from the first parameter value or a difference with respect to the first parameter value, that is used to generate a second root sequence for a second transmission of the random access channel; and a transmitter that transmits the random access channel as the first transmission to a base station, based on the first root sequence corresponding to the first parameter value, and transmits the random access channel as the second transmission to the base station, based on the second root sequence corresponding to the second parameter value or the difference.

[0300] With the above configuration, the random access channel preamble sequence for the second transmission of the random access channel is based on a root sequence different from the root sequence for the first transmission of the random access channel, thereby suppressing or avoiding collision between the first transmission of the random access channel and the second transmission of the random access channel, thereby enabling appropriate repeated transmission of the random access channel in the random access procedure.

[0301] In the terminal, the first parameter value and the second parameter value are root sequence identifier values, and when multiple root sequence identifier values ​​are used based on the second parameter value or the difference, the control unit sets the second root sequence by skipping the root sequence identifier value corresponding to the first parameter value.

[0302] With the above configuration, even when a plurality of root sequence identifier values ​​are used for the second transmission of the random access channel, it is possible to avoid the root sequence identifier value used for the first transmission of the random access channel.

[0303] In this terminal, the second parameter value or the difference is notified from the base station to the terminal by at least one of RRC (Radio Resource Control), MAC-CE (Medium Access Control - Control Element), and DCI (Downlink Control Information).

[0304] With the above configuration, the setting of the root sequence for the second transmission of the random access channel can be controlled flexibly (when RRC is used) or dynamically (when MAC-CE, DCI is used).

[0305] Furthermore, according to an embodiment of the present disclosure, there is provided a terminal including: a control unit that sets the number of preambles usable per resource for a random access channel, the number being greater than 64; and that randomly sets a first preamble for a first transmission of the random access channel from the usable preambles; and a transmission unit that transmits the random access channel including the first preamble to a base station as the first transmission, and transmits the random access channel including the second preamble to the base station as the second transmission.

[0306] With the above configuration, the number of preambles for transmission of the random access channel is increased compared to the number of preambles in the past, and the preambles randomly set for the first transmission of the random access channel and the second transmission of the random access channel are likely to be different, so that collision between the first transmission of the random access channel and the second transmission of the random access channel can be suppressed or avoided, thereby enabling appropriate repeated transmission of the random access channel in the random access procedure.

[0307] Furthermore, according to an embodiment of the present disclosure, there is provided a communications method in which a terminal sets a first parameter value used to generate a first root sequence for a first transmission of a random access channel and a second parameter value different from the first parameter value or a difference with respect to the first parameter value, used to generate a second root sequence for a second transmission of the random access channel; transmits the random access channel as the first transmission to a base station based on the first root sequence corresponding to the first parameter value; and transmits the random access channel as the second transmission to the base station based on the second root sequence corresponding to the second parameter value or the difference.

[0308] With the above configuration, the random access channel preamble sequence for the second transmission of the random access channel is based on a root sequence different from the root sequence for the first transmission of the random access channel, thereby suppressing or avoiding collisions between the initial transmission of the random access channel and the repeated transmission of the random access channel, thereby enabling appropriate repeated transmission of the random access channel in the random access procedure.

[0309] Furthermore, according to an embodiment of the present disclosure, there is provided a communication method in which a terminal sets the number of preambles available for use per resource for a random access channel, the number being greater than 64, randomly sets a first preamble for a first transmission of the random access channel from among the available preambles, randomly sets a second preamble for a second transmission of the random access channel from among the available preambles, transmits the random access channel including the first preamble to a base station as the first transmission, and transmits the random access channel including the second preamble to the base station as the second transmission.

[0310] With the above configuration, the number of preambles for transmission of the random access channel is increased compared to the number of preambles in the past, and the preambles randomly set for the first transmission of the random access channel and the second transmission of the random access channel are likely to be different, so that collision between the first transmission of the random access channel and the second transmission of the random access channel can be suppressed or avoided, thereby enabling appropriate repeated transmission of the random access channel in the random access procedure.

[0311] <Regarding Solution 5> According to an embodiment of the present disclosure, there is provided a terminal including: a control unit that sets a first preamble identifier for a first transmission of a random access channel from a first group including a first number of preamble identifiers for the first transmission, out of a first specific number of preamble identifiers, and sets a second preamble identifier for a second transmission from a second group including a second number of preamble identifiers for a second transmission of the random access channel, the second number being the first specific number minus the first number; and a transmission unit that transmits the random access channel as the first transmission to a base station based on the first preamble identifier, and transmits the random access channel as the second transmission to the base station based on the second preamble identifier.

[0312] With the above configuration, the preamble group for the first transmission of the random access channel and the preamble group for the second transmission of the random access channel are distinguished, and the preamble identifier used for the second transmission of the random access channel is different from the preamble identifier used for the first transmission of the random access channel. Therefore, even when using existing RO, collision between the first transmission of the random access channel and the second transmission of the random access channel can be suppressed or avoided. Therefore, repeated transmission of the random access channel can be appropriately performed in the random access procedure. Furthermore, because additional resources for the second transmission of the random access channel are not used, the load and resource efficiency of the base station that blindly decodes the random access channel can be maintained as before.

[0313] In this terminal, the terminal further includes a receiving unit that receives the first number or the second number from the base station, and when the first number is received, the control unit subtracts the first number from the first specific number to set the second number, and when the second number is received, the control unit subtracts the second number from the first specific number to set the first number.

[0314] With the above configuration, only the number of preamble identifiers for one preamble group is notified to the terminal, so that an increase in the amount of signaling can be suppressed.

[0315] In this terminal, the first group and the second group are divided from a predefined third group including a third number of preamble identifiers out of a second specific number of preamble identifiers, and are divided from a predefined fourth group including a fourth number of preamble identifiers obtained by subtracting the third number from the second specific number.

[0316] With the above configuration, it is possible to use already defined groups, thereby reducing the need to change specifications.

[0317] Furthermore, according to an embodiment of the present disclosure, there is provided a terminal including: a control unit that sets, within a period, a first period for a first transmission of a random access channel and a second period different from the first period for a second transmission of the random access channel; and a transmission unit that transmits the random access channel to a base station as the first transmission in the first period and transmits the random access channel to the base station as the second transmission in the second period.

[0318] With the above configuration, the first transmission of the random access channel and the second transmission of the random access channel are performed in different periods, so that collision between the first transmission of the random access channel and the second transmission of the random access channel can be suppressed or avoided even when using existing RO. Therefore, repeated transmission of the random access channel can be performed appropriately in the random access procedure. Furthermore, because additional resources for the second transmission of the random access channel are not used, the load and resource efficiency of the base station that blindly decodes the random access channel can be maintained as before.

[0319] Furthermore, according to an embodiment of the present disclosure, there is provided a communication method in which a terminal sets a first preamble identifier for a first transmission of a random access channel from a first group including a first number of preamble identifiers for the first transmission, out of a first specific number of preamble identifiers, sets a second preamble identifier for a second transmission of the random access channel from a second group including a second number of preamble identifiers for the second transmission, the second number being the first specific number minus the first number, transmits the random access channel to a base station as the first transmission based on the first preamble identifier, and transmits the random access channel to the base station as the second transmission based on the second preamble identifier.

[0320] With the above configuration, the preamble group for the first transmission of the random access channel and the preamble group for the second transmission of the random access channel are distinguished, and the preamble identifier used for the second transmission of the random access channel is different from the preamble identifier used for the first transmission of the random access channel. Therefore, even when using existing RO, collision between the first transmission of the random access channel and the second transmission of the random access channel can be suppressed or avoided. Therefore, repeated transmission of the random access channel can be appropriately performed in the random access procedure. Furthermore, because additional resources for the second transmission of the random access channel are not used, the load and resource efficiency of the base station that blindly decodes the random access channel can be maintained as before.

[0321] Furthermore, according to an embodiment of the present disclosure, there is provided a communication method in which a terminal sets, within a period, a first period for a first transmission of a random access channel and a second period different from the first period for a second transmission of the random access channel, transmits the random access channel to a base station as the first transmission in the first period, and transmits the random access channel to the base station as the second transmission in the second period.

[0322] With the above configuration, the first transmission of the random access channel and the second transmission of the random access channel are performed in different periods, so that collision between the first transmission of the random access channel and the second transmission of the random access channel can be suppressed or avoided even when using existing RO. Therefore, repeated transmission of the random access channel can be performed appropriately in the random access procedure. Furthermore, because additional resources for the second transmission of the random access channel are not used, the load and resource efficiency of the base station that blindly decodes the random access channel can be maintained as before.

[0323] (Supplementary Notes on the Embodiments) Although the embodiments of the present disclosure have been described above, the disclosed invention is not limited to such embodiments, and those skilled in the art will understand various modifications, alterations, alternatives, and substitutions. While specific numerical examples have been used to facilitate understanding of the invention, unless otherwise specified, these numerical values ​​are merely examples, and any appropriate values ​​may be used. The division of items in the above description is not essential to the present disclosure; matters described in two or more items may be used in combination as needed, and matters described in one item may apply to matters described in another item (unless inconsistent). Boundaries between functional units or processing units in functional block diagrams do not necessarily correspond to boundaries between physical components. The operations of multiple functional units may be performed by a single physical component, or the operations of a single functional unit may be performed by multiple physical components. The order of processing steps described in the embodiments may be reversed as long as there is no contradiction. For convenience of processing description, base station 100 and terminal 200 have been described using functional block diagrams. However, such devices may be implemented using hardware, software, or a combination thereof. The software operated by the processor of the base station 100 in accordance with an embodiment of the present disclosure and the software operated by the processor of the terminal 200 in accordance with an embodiment of the present disclosure may each be stored in random access memory (RAM), flash memory, read-only memory (ROM), EPROM, EEPROM, registers, hard disk (HDD), removable disk, CD-ROM, database, server, or any other suitable storage medium.

[0324] <Notification of Information, Signaling> Notification of information is not limited to the embodiments described in the present disclosure and may be performed using other methods. For example, notification of information may be performed by physical layer signaling (e.g., Downlink Control Information (DCI), Uplink Control Information (UCI)), higher layer signaling (e.g., Radio Resource Control (RRC) signaling, Medium Access Control (MAC) signaling, broadcast information (Master Information Block (MIB), System Information Block (SIB))), other signals, or a combination thereof. Furthermore, RRC signaling may be referred to as an RRC message, and may be, for example, an RRC Connection Setup message, an RRC Connection Reconfiguration message, or the like.

[0325] <Applicable Systems> The embodiments described in the present disclosure may be applied to at least one of systems using LTE (Long Term Evolution), LTE-Advanced (LTE-A), SUPER 3G, IMT-Advanced, 4G (4th generation mobile communication system), 5G (5th generation mobile communication system), FRA (Future Radio Access), NR (new Radio), W-CDMA (registered trademark), GSM (registered trademark), CDMA2000, UMB (Ultra Mobile Broadband), IEEE 802.11 (Wi-Fi (registered trademark)), IEEE 802.16 (WiMAX (registered trademark)), IEEE 802.20, UWB (Ultra-Wide Band), Bluetooth (registered trademark), or other appropriate systems, and next-generation systems extended based on these. Furthermore, a combination of multiple systems (e.g., a combination of at least one of LTE and LTE-A with 5G) may also be applied.

[0326] <Processing Procedures, etc.> The processing procedures, sequences, flowcharts, etc. of each aspect / embodiment described in this disclosure may be rearranged 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.

[0327] <Operation of Base Station> In the present disclosure, specific operations described as being performed by a base station may also be performed by its upper node in some cases. In a network consisting of one or more network nodes having a base station, it is clear that various operations performed for communication with a terminal may be performed by at least one of the base station and another network node other than the base station (for example, an MME or an S-GW, etc., but are not limited to these). Although the above example illustrates a case where there is one other network node other than the base station, a combination of multiple other network nodes (for example, an MME and an S-GW) may also be used.

[0328] <Direction of Input / Output> Information, etc. (see <Information, Signal>) can be output from a higher layer (or a lower layer) to a lower layer (or a higher layer). It may also be input / output via multiple network nodes.

[0329] <Handling of Input / Output Information, etc.> Input / output information, etc. may be stored in a specific location (for example, memory) or may be managed using a management table. Input / output information, etc. may be overwritten, updated, or added. Output information, etc. may be deleted. Input information, etc. may be sent to another device.

[0330] <Determination method> The determination may be made based on a value represented by one bit (0 or 1), a Boolean value (true or false), or a comparison of numerical values ​​(e.g., comparison with a predetermined value).

[0331] <Variations of Aspects, etc.> Each aspect / embodiment described in the present disclosure may be used alone, in combination, or switched depending on the implementation. In addition, notification of predetermined information (e.g., notification that "X is true") is not limited to being done explicitly, but may be done implicitly (e.g., by not notifying the predetermined information).

[0332] Although the present disclosure has been described in detail above, it is clear to those skilled in the art that the present disclosure is not limited to the embodiments described herein. The present disclosure can be implemented in modified and altered forms without departing from the spirit and scope of the present disclosure as defined by the claims. Therefore, the description of the present disclosure is intended to be illustrative and does not have any limiting meaning on the present disclosure.

[0333] <Software> 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.

[0334] 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), then these wired and / or wireless technologies are included within the definition of transmission media.

[0335] 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., which 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.

[0336] Note that terms described in this disclosure and terms necessary for understanding this disclosure may be replaced with terms having the same or similar meanings. For example, at least one of a channel and a symbol may be a signal (signaling). Furthermore, a signal may be a message. Furthermore, a component carrier (CC) may be called a carrier frequency, a cell, a frequency carrier, etc.

[0337] <System, Network> As used in this disclosure, the terms "system" and "network" are used interchangeably.

[0338] <Parameter and Channel Names> Furthermore, the information, parameters, and the like described in the present disclosure may be expressed using absolute values, relative values ​​from a predetermined value, or other corresponding information. For example, a radio resource may be indicated by an index.

[0339] The names used for the above-described parameters are not intended to be limiting in any way. Furthermore, the mathematical expressions using these parameters may differ from those explicitly disclosed in this disclosure. The various channels (e.g., 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.

[0340] <Base Station> In the present disclosure, terms such as "base station (BS)," "radio base station," "fixed station," "NodeB," "eNodeB (eNB)," "gNodeB (gNB)," "access point," "transmission point," "reception point," "transmission / reception point," "cell," "sector," "cell group," "carrier," and "component carrier" may be used interchangeably. A base station may also be referred to by terms such as a macrocell, a small cell, a femtocell, and a picocell.

[0341] 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 also be provided with communication services by a base station subsystem (e.g., a remote radio head (RRH)). The terms "cell" or "sector" refer to part or the entire coverage area of ​​a base station and / or base station subsystem that provides communication services within that coverage area.

[0342] Mobile Station In this disclosure, the terms "Mobile Station (MS)," "user terminal," "User Equipment (UE)," "terminal," and the like may be used interchangeably.

[0343] A mobile station may also be referred to by those skilled in the art as a subscriber station, mobile unit, subscriber unit, wireless unit, remote unit, mobile device, wireless device, wireless communication device, remote device, mobile subscriber station, access terminal, mobile terminal, wireless terminal, remote terminal, handset, user agent, mobile client, client, or some other suitable terminology.

[0344] <Base Station / Mobile Station> At least one of the base station and the mobile station may be referred to as a transmitting device, a receiving device, a communication device, etc. At least one of the base station and the mobile station may be a device mounted on a mobile body, the mobile body itself, etc. The mobile body may be a vehicle (e.g., a car, an airplane, etc.), an unmanned mobile body (e.g., a drone, an autonomous vehicle, etc.), or a robot (manned or unmanned). At least one of the base station and the mobile station may 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 IoT (Internet of Things) device such as a sensor.

[0345] Furthermore, the base station in the present disclosure may be read as a user terminal. For example, the 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, D2D (Device-to-Device) or V2X (Vehicle-to-Everything)). In this case, the UE 200 may be configured to have the functions of the gNB 100 described above. Furthermore, terms such as "uplink" and "downlink" may be read as terms corresponding to terminal-to-terminal communication (for example, "side"). For example, terms such as an uplink channel and a downlink channel may be read as a side channel.

[0346] Similarly, the user terminal in the present disclosure may be interpreted as a base station. In this case, the gNB 100 may be configured to have the functions of the UE 200 described above.

[0347] <Meaning and Interpretation of Terms> As used in this disclosure, the terms "determining" and "determining" may encompass a wide variety of actions. "Determining" and "determining" may include, for example, judging, calculating, computing, processing, deriving, investigating, looking up, searching, inquiring (e.g., searching a table, database, or other data structure), ascertaining something that is considered to be a "judging" or "determining," and the like. "Determining" and "determining" may also include receiving (e.g., receiving information), transmitting (e.g., sending information), input, output, accessing (e.g., accessing data in memory), and the like that are considered to be a "judging" or "determining." Furthermore, "judgment" and "decision" can include regarding resolving, selecting, choosing, establishing, comparing, etc. as having been "judged" or "decided." In other words, "judgment" and "decision" can include regarding some action as having been "judged" or "decided." Furthermore, "judgment (decision)" can be interpreted as "assuming," "expecting," "considering," etc.

[0348] 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." As used in this disclosure, two elements may be considered to be "connected" or "coupled" to each other using one or more wires, cables, and / or printed electrical connections, as well as electromagnetic energy having wavelengths in the radio frequency range, microwave range, and optical (both visible and invisible) range, as some non-limiting and non-exhaustive examples.

[0349] <Reference Signal> A reference signal can also be abbreviated as RS (Reference Signal), and may also be called a pilot depending on the applicable standard.

[0350] <Meaning of "based on"> 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."

[0351] "First," "Second" Any reference to an element using designations such as "first," "second," etc., used in this disclosure does not generally limit the quantity or order of those elements. These designations may be used in this disclosure as a convenient 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 precede the second element in some way.

[0352] <Means> The "means" in the configuration of each device above may be replaced with "section," "circuit," "device," etc.

[0353] Open Format: 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.

[0354] <Time Units such as TTI, Frequency Units such as RB, and Radio Frame Configuration> A radio frame may be composed of one or more frames in the time domain. Each of the one or more frames in the time domain may be called a subframe. A subframe may further 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.

[0355] Numerology may be a communication parameter that applies to the transmission and / or reception of a signal or channel, and may indicate, for example, at least one of subcarrier spacing (SCS), bandwidth, symbol length, cyclic prefix length, transmission time interval (TTI), number of symbols per TTI, radio frame structure, specific filtering operations performed by the transceiver in the frequency domain, and specific windowing operations performed by the transceiver in the time domain.

[0356] 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 be a time unit based on numerology.

[0357] 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 (or PUSCH) mapping type A. A PDSCH (or PUSCH) transmitted using a minislot may be called PDSCH (or PUSCH) mapping type B.

[0358] The radio frame, subframe, slot, minislot, and symbol all represent time units for transmitting signals, and may be referred to by other names corresponding to the radio frame, subframe, slot, minislot, and symbol.

[0359] For example, one subframe may be called a transmission time interval (TTI), multiple consecutive subframes may be called a TTI, or one slot or one minislot may be called 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.

[0360] 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.

[0361] 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.

[0362] 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.

[0363] A TTI having a time length of 1 ms may be called a regular TTI (TTI in LTE 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.

[0364] 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.

[0365] 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.

[0366] The time domain of an RB may include one or more symbols and may have a length of one slot, one minislot, one subframe, or one TTI. One TTI, one subframe, etc. may each be composed of one or more resource blocks.

[0367] Note that one or more RBs may also be called a physical resource block (PRB), a sub-carrier group (SCG), a resource element group (REG), a PRB pair, an RB pair, etc.

[0368] 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.

[0369] A Bandwidth Part (BWP) (which may also be referred to as a fractional 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.

[0370] The BWP may include a BWP for UL (UL BWP) and a BWP for DL ​​(DL BWP). One or more BWPs may be configured for a UE within one carrier.

[0371] 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."

[0372] The above-described structures of radio frames, subframes, slots, minislots, symbols, etc. are merely examples, and various changes may be made to 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.

[0373] <Maximum Transmit Power> The "maximum transmit power" in the present disclosure may refer to the maximum value of transmit power, the nominal UE maximum transmit power, or the rated UE maximum transmit power.

[0374] Articles 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.

[0375] <"Different"> In the present disclosure, the term "A and B are different" may mean "A and B are different from each other." Note that 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."

[0376] The present disclosure is useful in wireless communication systems.

[0377] 10 Wireless communication system 20 NG-RAN 100 gNB (base station) 200 UE (terminal) 101, 202 Transmitter 102, 201 Receiver 103, 203 Controller 1001 Processor 1002 Memory 1003 Storage 1004 Communication device 1005 Input device 1006 Output device 1007 Bus

Claims

1. A receiving unit that receives an index instructing a configuration of a physical random access channel; A transmitter that repeatedly transmits a message to be transmitted on an additional physical random access channel at a repetition number that corresponds one-to-one to the index; A terminal having the above configuration.

2. A transmitter that transmits an index instructing the setting of a physical random access channel; a receiver for receiving a message transmitted on an additional physical random access channel, the message being repeated at a repetition number corresponding one-to-one to the index; A base station having

3. A transmitter that transmits an index instructing the setting of a physical random access channel; a receiver for receiving a message transmitted on an additional physical random access channel, the message being repeated at a repetition number corresponding one-to-one to the index; a base station having A receiving unit for receiving the index; A transmitter that repeatedly transmits a message to be transmitted on an additional physical random access channel at a repetition number that corresponds one-to-one to the index; A terminal having A wireless system having the following:

4. The device is receiving an index indicating a configuration of a physical random access channel; The message to be transmitted in the additional physical random access channel is repeatedly transmitted at a repetition number that corresponds one-to-one with the index. Communication methods.