Terminal, wireless communication system, and wireless communication method

Abstract

To provide a terminal, a wireless communication system, and a wireless communication method that can appropriately switch between multiple types of random access opportunities (e.g., RACH-occasion).SOLUTION: In a wireless communication system, a terminal 200 includes a control unit 203 that sets the type of repetition occasion on the basis of whether to support switching the type of repetition occasion for a random access signal or not, and a transmission unit 202 that transmits a signal on an occasion of the type set by the control unit 203.SELECTED DRAWING: Figure 18

Description

[Technical Field]

[0001] The present disclosure relates to a terminal, a wireless communication system, and a wireless communication method. [Background technology]

[0002] 3GPP (registered trademark) has established specifications for the 5th generation mobile communication system (also known as 5G, New Radio (NR) or Next Generation (NG)), and is also working on specifications for the next generation mobile communication system, known as Beyond 5G, 5G Evolution, or 6G.

[0003] Release 18 discusses a duplexing scheme that enables simultaneous use of the downlink (DL) and uplink (UL) by utilizing multiple subbands that make up a time division duplexing (TDD) band. This duplexing scheme is called subband non-overlapping full duplex (SBFD). Note that symbols to which SBFD is applied may also be called SBFD symbols. In addition, in SBFD symbols, subbands used for DL ​​may also be called DL subbands, and subbands used for UL may also be called UL subbands.

[0004] Furthermore, for Release 19, extensions regarding UL transmission and DL reception across SBFD and non-SBFD symbols in different slots are being considered (Non-Patent Document 1). [Prior art documents] [Non-patent literature]

[0005] [Non-Patent Document 1] “New WID: Evolution of NR duplex operation: Subband full duplex (SBFD)”, RP-234035, 3GPP TSG RAN Meeting #102, 3GPP, December 11-15, 2023 [Non-patent document 2] 3GPP TS 38.214 V18.3.0 (2024-06) [Non-patent document 3] 3GPP TS 38.300 V18.2.0 (2024-06) [Non-patent document 4] 3GPP TS 38.331 V18.1.0 (2024-03) [Non-patent document 5] 3GPP TR 38.858 V18.1.0 (2024-03) Summary of the Invention

[0006] For random access in different types of symbols, such as SBFD symbols and non-SBFD symbols, multiple types of random access opportunities (e.g., RACH occasions) have been considered, but there is room for consideration regarding switching between these multiple types.

[0007] One aspect of the present disclosure contributes to providing a terminal, a wireless communication system, and a wireless communication method that can appropriately switch between multiple types of random access opportunities (for example, RACH opportunities (RACH occasions)).

[0008] A terminal according to one aspect of the present disclosure includes a control unit that sets the type of repetition opportunity for a random access signal based on whether or not it supports switching of the type of the repetition opportunity, and a communication unit that transmits the signal at the opportunity of the type set by the control unit. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a diagram illustrating an overall schematic configuration of a wireless communication system. [Figure 2] FIG. 1 illustrates frequency ranges used in wireless communication systems. [Figure 3] 1A to 1C are diagrams illustrating examples of the configuration of radio frames, subframes, slots, and symbols used in a radio communication system. [Figure 4A] FIG. 1 is a diagram illustrating an example of TDD settings defined up to Rel-16. [Figure 4B] FIG. 1 is a diagram illustrating an example of the configuration of SBFD. [Figure 5] FIG. 10 is a diagram illustrating an example of SBFD operation. [Figure 6A] FIG. 1 illustrates an example of an existing TDD configuration. [Figure 6B] A diagram showing an example of TDD including SBFD configuration. [Figure 7A] FIG. 1 illustrates pure time units and SBFD time units. [Figure 7B] FIG. 1 illustrates pure time units and SBFD time units. [Figure 7C] FIG. 1 illustrates pure time units and SBFD time units. [Figure 7D] FIG. 1 illustrates pure time units and SBFD time units. [Figure 7E] FIG. 1 illustrates pure time units and SBFD time units. [Figure 8] FIG. 10 is a sequence diagram illustrating an example of a CBRA procedure. [Figure 9] FIG. 10 is a sequence diagram illustrating another example of the CBRA procedure. [Figure 10] FIG. 10 is a sequence diagram illustrating an example of a CFRA procedure. [Figure 11] A diagram showing examples of RACH configuration options. [Figure 12] FIG. 10 is a diagram illustrating an example of RACH attempts and changes in repetition factor. [Figure 13] FIG. 10 is a diagram illustrating an example of switching between RACH attempts and RACH opportunities. [Figure 14]This figure shows examples of each option in Proposal 2-3A. [Figure 15] This figure shows examples of options B-1, B-2, and B-3 of Proposal 2-3B. [Figure 16] This is a diagram showing an example in which option B-4 of proposal 2-3B is applied. [Figure 17] FIG. 2 is a block diagram showing an example of the configuration of a base station. [Figure 18] FIG. 2 is a block diagram showing an example of the configuration of a terminal. [Figure 19] FIG. 2 is a diagram illustrating an example of the hardware configuration of a base station and a terminal. [Figure 20] FIG. 1 is a diagram illustrating an example of a configuration of a vehicle. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments will be described with reference to the drawings. Note that the same or similar reference numerals are used to designate the same functions or configurations, and descriptions thereof will be omitted as appropriate.

[0011] <Wireless communication system configuration> 1 is a wireless communication system conforming to a scheme called 5G. Alternatively, the wireless communication system 10 may be a wireless communication system conforming to a scheme called Beyond 5G, 5G Evolution, or 6G.

[0012] The wireless communication system 10 can support Massive Multiple-Input Multiple-Output (Massive MIMO), which generates more directional beams by controlling wireless signals transmitted from multiple antenna elements, Carrier Aggregation (CA), which uses multiple component carriers (CCs) by bundling them together, and Dual Connectivity (DC), which communicates with two base stations simultaneously. In this specification, "and / or" may be simply written as " / ".

[0013] As shown in FIG. 1, a wireless communication system 10 includes a base station 100 (hereinafter also referred to as a gNodeB (gNB) 100) constituting a Next Generation-Radio Access Network (NG-RAN) 20, and a terminal 200 (hereinafter also referred to as a user equipment (UE) 200) that performs wireless communication with the gNB 100. The NG-RAN 20 is connected to a core network (CN) (not shown). The CN is composed of multiple network functions (NFs). The NFs are, for example, an access and mobility management function (AMF) and a network data analytics function (NWDAF). The AMF performs, for example, registration of the UE 200. The NWDAF performs, for example, optimization of the CN. Note that the specific configuration of the wireless communication system 10, for example, the number of gNBs 100 and UEs 200, is not limited to the example shown in FIG. 1. The NG-RAN 20 and the CN may be simply referred to as a "network."

[0014] The gNB100 may be a base station in a Centralized-Radio Access Network (C-RAN) configuration having a distributed unit (DU) having a function for connecting to the UE200 and a central unit (CU) having a function for connecting to the network. In this case, the gNB100 may be read as a DU, a CU, or a DU and a CU. When read as a DU, the gNB100 may be called a gNB-DU. When read as a CU, the gNB100 may be called a gNB-CU. When read as a DU and a CU, the DU portion may be called a gNB-DU and the CU portion may be called a gNB-CU.

[0015] Furthermore, the wireless communication system 10 may support a plurality of frequency ranges (FRs). That is, as shown in FIG. 2, the wireless communication system 10 may support the following FRs: FR1: 410MHz~7.125GHz FR2-1: 24.25GHz~52.6GHz ·FR2-2: More than 52.6GHz~71GHz

[0016] In FR1, a subcarrier spacing (SCS) of 15, 30, or 60 kHz and a bandwidth (BW) of 5 to 100 MHz may be used, and in FR2-1, an SCS of 60 or 120 kHz (or 240 kHz) and a BW of 50 to 400 MHz may be used.

[0017] Note that SCS may be interpreted as numerology, which is defined in §5.1 of Non-Patent Document 3 and corresponds to one subcarrier interval in the frequency domain.

[0018] In FR2-2, to avoid an increase in phase noise, Cyclic Prefix-Orthogonal Frequency Division Multiplexing (CP-OFDM) or Discrete Fourier Transform-Spread-Orthogonal Frequency Division Multiplexing (DFT-S-OFDM) with a larger SCS may be applied.

[0019] Fig. 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 made up 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.

[0020] 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.

[0021] The time direction (t) shown in Fig. 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.

[0022] The wireless communication system 10 may support coverage enhancement (CE) that expands the coverage of a cell (or a 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 repetition of a physical random access channel (PRACH), may be provided.

[0023] 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.).

[0024] Furthermore, for example, the UE 200 transmits the PRACH as an UL signal to the gNB 100 using a RACH occasion, i.e., a RACH (transmission) opportunity (RO), which is a resource for transmitting a random access preamble. For example, the UE 200 repeats the PRACH as an UL signal to the gNB 100.

[0025] 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.

[0026] Channels used for transmitting UL signals include, for example, data channels and control channels. For example, the data channels may include a Physical Uplink Shared Channel (PUSCH), and the control channels 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 channels may also be called data channels.

[0027] The reference signal included in the UL signal may include at least one of, for example, 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 positioning 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.

[0028] Meanwhile, gNB100 transmits information related to the RACH procedure to UE200 as a DL signal (e.g., SIB1, etc.) in response to the operation of UE200.

[0029] Furthermore, for example, the gNB 100 receives, as an UL signal, a PRACH from the UE 200. For example, the gNB 100 receives, as an UL signal, a PRACH from the UE 200 in a repetition manner.

[0030] The channels used for transmitting DL signals include, for example, data channels and control channels. For example, the data channels may include a Physical Downlink Shared Channel (PDSCH), and the control channels may include a Physical Downlink Control Channel (PDCCH). For example, gNB100 transmits control information to UE200 using PDCCH and transmits DL data signals using PDSCH. Note that PDSCH is an example of a downlink shared channel, and PDCCH is an example of a downlink control channel. Note that PDCCH may be rewritten with downlink control information (DCI) transmitted in PDCCH, control information, etc.

[0031] The reference signals included in the DL signal may include, for example, at least one of DMRS, PTRS, CSI-RS, SRSRS, and PRS for location information. For example, reference signals such as DMRS and PTRS are used for demodulating DL data signals and are transmitted using PDSCH.

[0032] Next, SBFD, CG (Configured Grant), PUSCH / SPS (Semi-Persistent Scheduling), and PDSCH will be described.

[0033] <SBFD operation> Considering the transmission / reception time ratio (e.g., DL:UL=4:1) in Time Division Duplex (TDD) up to Rel-16, there may be cases where the number of transmission opportunities for UL signals / channels is fewer than the number of reception opportunities for DL ​​signals / channels. In such cases, UE 200 cannot transmit UL signals / channels frequently, which raises concerns about transmission delays of important UL signals / channels. Furthermore, since there are fewer UL transmission opportunities compared to DL reception opportunities, there is also concern about signal / channel congestion during UL transmission opportunities. Furthermore, with TDD, the time resources available for transmitting UL signals / channels are limited, which limits the application of UL coverage extension techniques, such as repetition transmission.

[0034] In future wireless communication systems (for example, Rel-18 and later), the introduction of a time-frequency division duplexing method that combines TDD and frequency division duplexing (FDD) for UL and DL is being considered.

[0035] Examples of the time-frequency division duplexing method include XDD (Cross Division Duplex) and Subband Non-Overlapping Full Duplex (SBFD). XDD or SBFD may refer to a duplexing method that frequency-division multiplexes DL and UL within one component carrier (CC) in the TDD band (allowing DL and UL to be used simultaneously).

[0036] Figure 4A is a diagram showing an example of the TDD configuration defined up to Rel-16. In the example shown in Figure 4A, TDD slots or symbols are configured for a UE in a bandwidth such as one component carrier (CC) (which may also be called a cell or serving cell) or bandwidth portion (BWP).

[0037] In the example shown in Figure 4A, the time ratio of DL slots to UL slots is 4:1. This conventional TDD slot or symbol configuration does not ensure sufficient UL time resources, which can result in UL transmission delays and reduced coverage performance.

[0038] Fig. 4B is a diagram showing an example of the configuration of SBFD. In the example shown in Fig. 4B, within one component carrier (CC), resources used for DL ​​reception and resources used for UL transmission overlap in time. With such a resource configuration, more UL resources can be secured, thereby improving resource utilization efficiency.

[0039] For example, as shown in the example of Figure 4B, both ends of the frequency domain may be set as DL resources, and UL resources may be sandwiched between these DL resources. This may prevent or mitigate cross link interference (CLI) with neighboring carriers. Also, a guard region may be set at the boundary between the DL resources and the UL resources.

[0040] Considering the complexity of handling self-interference, it may be considered that only the gNB 100 uses the DL resource and the UL resource simultaneously. That is, in radio resources where the DL and UL overlap in time, one UE 200 may use the DL resource and another UE 200 may use the UL resource.

[0041] Fig. 5 is a diagram showing an example of SBFD operation. In the example shown in Fig. 5, part of the DL resources of the TDD band is set as the UL resources, and the DL and UL are configured to partially overlap in the time domain.

[0042] In the example shown in FIG. 5, during the DL-only period, each of the multiple UEs 200 (UE1 and UE2 in FIG. 5) receives the DL channel / signal.

[0043] Furthermore, during a period in which DL and UL overlap in time, one UE 200 (UE1 in the example of FIG. 5) receives a DL channel / signal, and another UE 200 (UE2 in the example of FIG. 5) transmits a UL channel / signal. During this period, the gNB 100 performs simultaneous transmission and reception of DL and UL.

[0044] Furthermore, during the UL-only period, each of the multiple UEs 200 (UE1 and UE2 in FIG. 5) transmits a UL channel / signal.

[0045] In existing NR (e.g., those defined up to Rel-15 / 16 / 17), DL frequency resources and UL frequency resources in a UE carrier are configured as DL BWP and UL BWP, respectively. To switch DL / UL frequency resources to other DL / UL frequency resources, multiple BWP configurations and a BWP adaptation mechanism are required.

[0046] Figure 6A is a diagram showing an example of an existing TDD configuration. In Figure 6A, slots / symbols marked with "D" are DL slots / symbols, slots / symbols marked with "U" are UL slots / symbols, and slots / symbols marked with "F" are flexible (hereinafter also referred to as FL) slots / symbols. Note that similar notations may be used in the following figures.

[0047] In the existing NR, as shown in FIG. 6A, time resources (time units such as symbols and slots) in the TDD carrier for UE 200 are configured as at least one of DL, UL, and flexible (FL) in the TDD configuration.

[0048] Figure 6B is a diagram showing an example of an existing TDD configuration. In Figure 6B, slots / symbols or subbands marked with "D" are DL slots / symbols or DL ​​subbands, and slots / symbols or subbands marked with "U" are UL slots / symbols or UL subbands. Note that similar notations may be used in the following figures.

[0049] As shown in FIG. 6B , the SBFD symbol may be a symbol that is signaled or configured as UL (or DL) or for UL transmission (or DL ​​reception) on some frequency resources (subbands), and signaled or configured as DL (or UL) or for DL ​​reception (or UL transmission) on other frequency resources (subbands). Alternatively, the SBFD symbol may be a symbol that is signaled or configured as UL (or DL) or for UL transmission (or DL ​​reception) on a portion of frequency resources. Alternatively, the SBFD symbol may be a symbol that is signaled or configured as DL (or UL) or for DL ​​reception (or UL transmission) on a portion of frequency resources.

[0050] Here, the time unit may be at the symbol level, slot / subslot level, or a group of symbols / slots / subslots, i.e., the SBFD time unit may be an SBFD symbol, a slot / subslot containing or overlapping an SBFD symbol, or a group of symbols / slots / subslots containing or overlapping an SBFD symbol.

[0051] A pure time unit may be a non-SBFD symbol (i.e., a symbol that is not an SBFD symbol, also referred to as a non-SBFD symbol), a slot / subslot that does not contain or overlap an SBFD symbol, or a group of symbols / slots / subslots that do not contain or overlap an SBFD symbol, and may also be referred to as a non-SBFD time unit. For example, a pure time unit may be referred to as a time unit consisting only of DL on frequency resources as shown in Figure 7A, or as a time unit consisting only of UL on frequency resources as shown in Figure 7B.

[0052] Furthermore, for an SBFD time unit, DL resources and UL resources may have various allocation patterns in the frequency domain. For example, an SBFD time unit of frequency domain pattern #1 may have an allocation pattern as shown in FIG. 7C. An SBFD time unit of frequency domain pattern #2 may have an allocation pattern as shown in FIG. 7D. An SBFD time unit of frequency domain pattern #3 may have an allocation pattern as shown in FIG. 7E. These allocation patterns are merely exemplary, and other allocation patterns may also be used. The frequency domain pattern of an SBFD time unit may refer to a resource repetition pattern in the frequency domain for the SBFD time unit.

[0053] As described above, SBFD may be applied to each slot / symbol. Note that each slot / symbol may be set to DL, UL, or Flexible (FL) that can be used as DL or UL, and then SBFD may be applied.

[0054] SBFD is a type of (full-duplex) duplexing scheme based on time division duplexing (TDD), enabling simultaneous use of multiple sub-bands that make up the TDD band. SBFD can be described as a duplexing scheme in which multiple sub-bands are specified within the TDD band, a duplexing scheme in which UL and DL are allocated non-overlapping in the frequency direction within the TDD time unit, or full-duplex duplexing of sub-bands.

[0055] A symbol to which SBFD is applied is also called an SBFD symbol. "SBFD is applied" may be interpreted as SBFD being applied to at least a part of scheduling. In other words, a "symbol to which SBFD is applied" may be interpreted as a symbol to which SBFD is applied (SBFD symbol) in scheduling to which SBFD is applied. Also, a "time unit to which non-SBFD is applied" may be interpreted as a symbol to which SBFD is not applied (non-SBFD symbol) in scheduling to which SBFD is applied.

[0056] Furthermore, a UE that supports SBFD operation (SBFD-compatible UE) is referred to as an SBFD-aware UE or an SBFD-capable UE, and a UE that does not support SBFD operation is referred to as a legacy UE. For example, when SBFD is applied to a DL symbol, an SBFD-aware UE can recognize the UL subband (and DL subband) in this SBFD symbol, but a legacy UE recognizes this SBFD symbol as a normal DL symbol.

[0057] <Random access procedure> NR random access procedures are performed for various purposes, such as initial access, recovery from beam interference, and handover. Random access procedures include a contention-based random access (CBRA) procedure, which is a contention-based random access procedure, and a contention-free random access (CFRA) procedure, which is a contention-free random access procedure. Since the CBRA procedure is initiated autonomously by the UE 200, collisions may occur when multiple UEs 200 simultaneously initiate the random access procedure. On the other hand, the CFRA procedure allows the gNB 100 to instruct the connected UE 200 to execute the random access procedure in a manner that prevents collisions from occurring among the multiple UEs 200.

[0058] 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.

[0059] FIG. 8 is a sequence diagram illustrating an example of the CBRA procedure.

[0060] For example, the gNB100 transmits an SSB for each beam, and the UE200 monitors the SSB of each beam. The UE200 selects an SSB from the multiple SSBs whose received power (RSRP: Reference Signal Received Power) is greater than a threshold (or equal to or greater than a threshold), and transmits a random access preamble to the gNB100 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 referred to as a preamble, a PRACH preamble, a message 1, an Msg1, or the like, as appropriate.

[0061] The gNB 100 transmits a response message to the Msg1 as a second message to the UE 200 via the PDSCH (step S102). The response message (second message) may be appropriately referred to as a Random Access Response (RAR), an RA Response, Message 2, Msg2, or the like. After transmitting the Msg1, the UE 200 may monitor the PDCCH used for scheduling the PDSCH including the Msg2. The 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.

[0062] 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 referred to as a Message 3, Msg 3, an RRC Connection Request, or the like, as appropriate.

[0063] The gNB 100 transmits a contention resolution message as a fourth message via the PDSCH (step S104). The contention resolution message (fourth message) may be referred to as Message 4, Msg4, or the like as appropriate. After transmitting Msg3, the UE 200 may monitor the PDCCH used for scheduling the PDSCH including Msg4. Msg4 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 Msg4 received by the UE 200 has the same value as an ID for identifying the UE 200, the UE 200 may determine that contention resolution is successful and set the value of a Temporary Cell - Radio Network Temporary Identifier (TC-RNTI) in a Cell - Radio Network Temporary Identifier (C-RNTI) field. When the value of TC-RNTI is set in the C-RNTI field, the UE 200 may consider the RRC connection to be completed. Msg4 may be referred to as RRC Connection Setup, etc.

[0064] After the RRC connection is completed, the UE 200 may transmit an Ack (Acknowledgement) via a PUCCH (PUCCH resource) indicated by a PUCCH resource indication field included in the PDCCH that scheduled the Msg4, in order to notify the gNB 100 that the RRC connection has been completed. After the RRC connection is established, the UE 200 may transmit UE capability to the gNB 100. The above-described random access procedure may be referred to as a Type 1 RACH procedure, a 4-step RACH procedure, Type 1 RACH, 4-step RACH, etc.

[0065] FIG. 9 is a sequence diagram illustrating another example of the CBRA procedure.

[0066] 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 selecting an RO in a 4-step RACH procedure, and transmits an RA preamble on the RO and transmits data on a PUSCH resource associated with the RO. This message may be appropriately referred to as Message A, MsgA, etc. Note that the RA preamble and data here may correspond to Msg1 and Msg3 in the 4-step RACH procedure, respectively. MsgA includes one RA preamble (referred to as MsgA PRACH) and one piece of data (referred to as MsgA PUSCH), and the MsgA PRACH and MsgA PUSCH are time-division multiplexed and transmitted. More specifically, the MsgA PRACH is one preamble with one preamble index in an MsgA RACH occasion (RO: RACH occasion), and the MsgA PUSCH is one PUSCH with one PUSCH resource unit (PRU: PUSCH resource unit) in an MsgA PUSCH occasion (PO: PUSCH occasion) according to the MsgA PUSCH configuration. Note that in this procedure, resources for transmitting data are not limited to PUSCH resources, and may be resources of any channel for transmitting data (or control information).

[0067] The gNB 100 transmits the response message to the UE 200 as a second message (step S202). This response message (second message) may be referred to as Message B, MsgB, or the like as appropriate. The content included in Message B may correspond to Msg2 and Msg4 in a 4-step RACH procedure, for example. MsgB includes one PDSCH (and one PDCCH for scheduling the PDSCH). From the perspective of the physical layer, the content of Msg2 and Msg4 is simply integrated into MsgB.

[0068] The UE 200, whose RRC connection has been completed, may transmit an Ack via a PUCCH (PUCCH resource) to notify the gNB 100 that the RRC connection has been completed. After the RRC connection is established, the UE 200 may transmit UE capability to the gNB 100. 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. The 2-step RACH is supported to shorten the RACH delay.

[0069] FIG. 10 is a sequence diagram illustrating an example of the CFRA procedure.

[0070] 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.

[0071] UE200 transmits the above-mentioned Msg1 to gNB100 (step S302).

[0072] 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 a UE capability to the gNB100.

[0073] In this embodiment, in order to achieve coverage expansion in the random access procedure, the UE 200 may repeatedly transmit Msg1 (and thus PRACH) in, for example, the 4-step RACH procedure shown in FIG. 8 and the CFRA procedure shown in FIG. 10 described above. However, in the present disclosure, Msg1 (and thus PRACH) may also be repeatedly transmitted in the 2-step RACH procedure shown in FIG. 9 described above.

[0074] In the random access described above, the UE determines a random access opportunity for transmitting a preamble to start the random access, and determines valid ROs (and invalid ROs that are invalid as ROs) that are valid as ROs from the determined ROs. Note that the random access opportunity may be referred to as a RACH Occasion.

[0075] Next, the power control of the PRACH and Msg3 transmitted by the UE 200 in the random access procedure shown in FIG. 8, and MsgA transmitted by the UE 200 in the random access procedure shown in FIG. 9 will be described. Note that since Msg3 and MsgA are each transmitted in the PUSCH, they may be referred to as Msg3 PUSCH and MsgA PUSCH.

[0076] <Consideration of Duplex Expansion for Rel-19> As described above, in Rel-18, studies have been made to enable the simultaneous presence of downlink and uplink (full duplex, more specifically sub-band non-overlapping full duplex) on the gNB side within the conventional TDD band. Regarding SBFD, the influence of specifications, performance evaluation results, implementation feasibility, and influence on RF requirements are summarized in Non-Patent Document 5.

[0077] In Non-Patent Document 1, studies have been centered on the expansion of sub-band non-overlapping full duplex (SBFD) operation on the gNB side within a TDD carrier. The purpose of the studies for Rel-19 is as follows. (1) Study on the specification of semi-static indication of the time position of SBFD subbands to UE in RRC_CONNECTED mode Indication of the time position of the SBFD subband in the SIB is not excluded (2) Study on the specification of semi-static indication of the frequency domain location of SBFD subbands to UE in RRC_CONNECTED mode Indication of the frequency domain location of SBFD subbands in the SIB is not excluded (3) Study on SBFD operation specifications to support random access of SBFD symbols by UE in RRC CONNECTED mode (4) Consider SBFD operation to support random access by UE in RRC_IDLE / INACTIVE mode and specify it if appropriate. ·Check whether standardization work will proceed in RAN#104 (5) Study on the specifications for the operation and procedures of SBFD-enabled UE (SBFD aware UE) transmission / reception and measurement of SBFD symbols and / or non-SBFD symbols. Transmit / receive operation in SBFD sub-bands configured for DL ​​and / or flexible symbols as indicated by TDD-UL-DL-ConfigCommon UL transmission only in the UL sub-band DL reception only within DL sub-band (excluding CLI measurements by UE outside DL sub-band) Note: When flexible symbols are used, it is not expected that legacy uplink symbols will be converted to downlink / SBFD symbols. Enhanced resource allocation in the frequency domain for the following SBFD symbols: Frequency domain resource allocation for PDSCH / CSI-RS across two DL subbands in an SBFD symbol Handling misalignment of boundaries between SBFD subbands and resource block groups (RBGs), CSI report subbands, CSI-RS resources, and precoding resource block groups (PRGs) Enhancements for physical channels / signals and procedures spanning SBFD and non-SBFD symbols in different slots, where each transmission / reception within a slot includes either all SBFD symbols or all non-SBFD symbols, including: Resource allocation in the frequency domain when transmitting / receiving SBFD and non-SBFD symbols using different available frequency resources in different slots CSI reports for related CSI-RS instances occurring in both SBFD and non-SBFD symbols in different slots SRS, PUCCH and PUSCH configurations in SBFD and non-SBFD symbols (e.g., resources, frequency hopping parameters, UL power control parameters and / or beam / spatial relationships) Collision handling between DL reception in DL sub-band and UL transmission in UL sub-band in SBFD symbols (6) Based on TR 38.858 (Non-Patent Document 5), the following is assumed: SBFD on the gNB side Half duplex operation on the UE side FR1 and FR2-1 SBFD operation option 4 (e.g., both the time and frequency location of the sub-bands for SBFD operation are known to the SBFD-capable UE) Coexistence of non-SBFD-capable UE (including legacy UE) and SBFD-capable UE in a cell where SBFD is operated on the gNB side SBFD method within a single DL and UL BWP pair with aligned center frequencies One UL subband for SBFD operation in SBFD symbols (excluding legacy UL symbols / slots) within a TDD carrier · The mechanism of SBFD operation needs to consider the coexistence of adjacent channels between two operators

[0078] <Transmission / reception spanning SBFD symbols and non-SBFD symbols> In §6.1. of Non-Patent Document 5, it is being examined whether to support transmission / reception spanning SBFD symbols and non-SBFD symbols.

[0079] Regarding UL transmission / DL reception spanning SBFD symbols and non-SBFD symbols in different slots (each transmission / reception within a slot is either all SBFD or all non-SBFD symbols), the following options are considered for SBFD-capable UEs. Option 1: Transmission / reception is restricted to only SBFD symbols or only non-SBFD symbols Option 2: Transmission / reception can be performed with SBFD symbols and non-SBFD symbols

[0080] UL transmission / DL reception spanning SBFD symbols and non-SBFD symbols includes the following information: · Repetition of PDSCH / PUSCH / PUCCH · SPS (Semi-Persistent Scheduling) PDSCH / CG PUSCH (Configured Grant PUSCH) · TBoMS (Transport Block processing over Multiple Slots) · Multiple (plural) PUSCH / PDSCH scheduled by a single DCI · Periodic / semi-persistent SRS / CSI-RS / PUCCH · PDCCH

[0081] Option 1 can be achieved by gNB configuration or scheduling such that all transmit / receive occasions are restricted to either SBFD symbols or non-SBFD symbols. Alternatively, Option 1 can be achieved by additional instructions or rules to determine which transmit / receive occasions are valid within one symbol type and invalid within other symbol types. The frequency resources, power control, and beam / spatial relationships for all transmit / receive occasions may be identical in Option 1 but may be different in Option 2. If different, additional work on the specifications may be required. Option 1 may / may not increase transmit / receive latency if transmit / receive in other symbol types is postponed, and may degrade performance if transmit / receive in other symbol types is dropped. Option 2 may / may not reduce transmit / receive latency and improve coverage.

[0082] <Terminology> The following explains the definitions of terms related to SBFD.

[0083] SBFD symbol: Symbol set in SBFD sub-band Non-SBFD symbols: Symbols that are not configured in the SBFD sub-bands DL (or semi-static D) symbol: A symbol designated as DL by tdd-UL-DL-ConfigurationCommon and / or tdd-UL-DL-ConfigDedicated UL (or semi-static U) symbol: A symbol designated as UL by tdd-UL-DL-ConfigurationCommon and / or TDD-UL-DL-ConfigDedicated Flexible (or Semi-Static F, or Flexible) Symbol: A symbol designated as flexible by tdd-UL-DL-ConfigurationCommon and / or tdd-UL-DL-ConfigDedicated SBFD DL symbol: A symbol indicated as downlink (DL) by the tdd-UL-DL-Configuration Common and / or tdd-UL-DL-Configuration Dedicated, in which the SBFD subband is configured SBFD Flexible (FL) Symbol: A symbol indicated as flexible by the tdd-UL-DL-Configuration Common and / or tdd-UL-DL-Configuration Dedicated, in which SBFD sub-bands are configured.

[0084] Parameters for configuring SRS (Sounding Reference Signal) resources may include SRS Config. SRS Config is a parameter that defines a list of SRS-ResourceSets and a list of SRS-Resources. An SRS-ResourceSet included in the list may include an SRS-ResourceSet identifier (srs-ResourceSetId), a list of SRS-Resource identifiers (srs-ResourceIdList), etc. An SRS-Resource included in the list includes an SRS-Resource identifier (srs-ResourceId), SRS resources in the frequency domain (e.g., resourceMapping), etc. ResourceMapping includes a start position (startPosition), the number of symbols (nrofSymbols), the number of repetitions (repetitionFactor), etc. SRS Config may be a parameter specified in §6.3.2 "Radio resource control information elements" of Non-Patent Document 4.

[0085] <3GPP Agreements> The following two options were considered for determining a valid RO in an SBFD symbol. Note that, hereinafter, a valid RO may be referred to as a valid RO. Option 1: Single PRACH configuration Option 2: Additional PRACH configuration for SBFD Note that in Option 1, a scalable single RACH configuration may be used, and RO within the UL subband in the SBFD symbol may be enabled for SBFD-aware UEs. In Option 2, two separate RACH configurations may be used, including a legacy RACH configuration and an additional RACH configuration, and RO within the UL subband in the SBFD symbol may be enabled for SBFD-aware UEs.

[0086] The following points were then agreed upon: For an SBFD-aware UE in RRC_CONNECTED state, RACH Configuration Option 1 with Alt 1-1 and RACH Configuration Option 2 are supported. Here, RACH Configuration Option 1 with Alt 1-1 is an option that uses a single RACH configuration and operates only based on the existing parameters of the single RACH configuration. RACH Configuration Option 2 uses two distinct RACH configurations. These two distinct configurations include one legacy RACH configuration and one additional RACH configuration. Note that it is not supported for both options to be available to a UE at the same time.

[0087] Fig. 11 is a diagram showing examples of RACH configuration options. Fig. 11 shows examples of RACH configuration for each of two options. The horizontal axis of each option in Fig. 11 indicates the time axis, and the vertical axis indicates the frequency axis. Each option in Fig. 11 shows ROs set for SBFD symbols and non-SBFD symbols.

[0088] As shown in Option 1 of Figure 11, in Option 1, the ROs for SBFD symbols and non-SBFD symbols are both configured by the legacy RACH configuration. As shown in Option 2 of Figure 11, in Option 2, the ROs for SBFD symbols are configured by an additional RACH configuration, and the ROs for non-SBFD symbols are configured by the legacy RACH configuration.

[0089] An RO called additional RO is defined as follows: For RACH configuration option 1, additional ROs include ROs within SBFD symbols configured as DL by tdd-UL-DL-ConfigurationCommon, and ROs across SBFD symbols configured as flexible by tdd-UL-DL-ConfigurationCommon and SBFD symbols configured as DL. For RACH configuration option 2, the additional RO is the RO configured by the additional RACH configuration.

[0090] Regarding the activation of RO for Option 1 of RACH configuration with Alt 1-1, an RO that straddles an SBFD symbol configured as flexible by tdd-UL-DL-ConfigurationCommon and an SBFD symbol configured as DL is treated the same as an RO within an SBFD symbol configured as DL by tdd-UL-DL-ConfigurationCommon, where the RO includes at least one DL symbol configured by tdd-UL-DL-ConfigurationCommon.

[0091] In RACH configuration option 2, additional RO is enabled in any of the following cases: - The RO is within the SBFD symbol If the RO starts with an SBFD symbol and ends with a non-SBFD symbol within the same slot or between different slots, the network will mark the RO as valid. The RO is N symbols after the last downlink non-SBFD symbol. gap Start at the symbol position The RO is the N after the latest SSB. gap Start at the symbol position The RO does not overlap with SSB in the time domain.

[0092] As described above, in RACH configuration option 1 with Alt 1-1 (ie, single RACH configuration), the legacy RO and additional RO correspond to the following ROs: Legacy ROs are ROs that are valid as legacy and contain UL or flexible symbols. Additional RO is an RO within the SBFD DL symbol or an RO spanning the SBFD DL symbol and the SBFD flexible symbol.

[0093] As described above, in RACH configuration option 2 (i.e., additional RACH configuration for SBFD), the legacy RO and additional RO correspond to the following ROs. · A legacy RO is a valid RO configured by a legacy RACH configuration. Additional RO is set as valid if the RO is within an SBFD symbol or if the RO starts with an SBFD symbol and ends with a non-SBFD symbol between the same slot or different slots as configured by the network through additional RACH configuration.

[0094] Note that "legacy RO" refers to a valid RO in a UL symbol or a flexible symbol that is configured by a legacy RACH configuration based on a legacy RO validity rule.

[0095] "Additional RO" represents the valid RO configured by the legacy PRACH configuration in the SBFD DL symbol when the additional PRACH configuration for SBFD is not configured.

[0096] Alternatively, "additional RO" refers to a valid RO configured by a legacy PRACH configuration across an SBFD DL symbol and an SBFD flexible symbol when an additional PRACH configuration for SBFD is not configured.

[0097] Alternatively, "additional RO" refers to a valid RO in an SBFD symbol set by the PRACH configuration for SBFD when the additional PRACH configuration for SBFD is set.

[0098] Alternatively, an "additional RO" is an RO that is set by a PRACH setting for SBFD when an additional PRACH setting for SBFD is set, and the network sets the RO as valid if the RO starts with an SBFD symbol and ends with a non-SBFD symbol, in the same slot or between different slots.

[0099] <Number of repetitions of Msg1 for the initial attempt> Regarding the repetition count of Msg1 exchanged in random access (RA), TS 38.321 (e.g., section 5.1.1b) specifies the following: Note that the repetition count of Msg1 (Msg1 repetition number) may also be written as Msg 1 repNum. If the BWP selected for the random access procedure is configured with a set of random access resources associated with an Msg1 repetition number of 8 and the RSRP referring to the downlink path loss is less than rsrp-ThresholdMsg1-RepetitionNum8, it is assumed that the Msg1 repetition number applicable to the current random access procedure includes 8. If the BWP selected for the random access procedure is configured with a set of random access resources associated with an Msg1 repetition number of 4 and the RSRP referring to the downlink path loss is less than rsrp-ThresholdMsg1-RepetitionNum4, it is assumed that the repetition number of Msg1 applied to the current random access procedure includes 4. If the BWP selected for the random access procedure is configured with a set of random access resources associated with Msg1 repetition number 2 and the RSRP referring to the downlink path loss is less than rsrp-ThresholdMsg1-RepetitionNum2, it is assumed that Msg1 repetition is applicable and that the Msg1 repetition number applied to the current random access procedure includes 2. ·Assuming that the repetition of Msg1 is applicable to the current random access procedure, in the case where at least one of rsrp-ThresholdMsg1-RepetitionNumX is set, one of the following (a1) to (a4) is assumed. · (a1) If rsrp-ThresholdMsg1-RepetitionNum8 is configured and the RSRP referring to the downlink path loss is less than rsrp-ThresholdMsg1-RepetitionNum8, it is assumed that the repetition count of Msg1 applied to the current random access procedure includes 8. · (a2) If rsrp-ThresholdMsg1-RepetitionNum4 is set and the RSRP referring to the downlink path loss is less than rsrp-ThresholdMsg1-RepetitionNum4, it is assumed that the repetition count of Msg1 applied to the current random access procedure includes 4. · (a3) ​​If rsrp-ThresholdMsg1-RepetitionNum2 is set and the RSRP referring to the downlink path loss is less than rsrp-ThresholdMsg1-RepetitionNum2, it is assumed that the repetition count of Msg1 applied to the current random access procedure includes 2. (a4) If the RSRP referring to the downlink path loss is not smaller than any of the configured rsrp-ThresholdMsg1-RepetitionNumX, the repetition factor of Msg1 applicable to the current random access procedure is assumed to be the smallest repetition factor of Msg1 configured for this BWP, where X in NumX may be 2, 4, or 8. · If neither rsrp-ThresholdMsg1-RepetitionNumX is set, the repetition count of Msg1 applied to the current random access procedure is assumed to be the repetition count of Msg1 set in this BWP.

[0100] That is, according to the provisions of TS 38.321 (e.g., Section 5.1.1b), the number of repetitions of Msg1 is determined based on the configured RSRP threshold (e.g., rsrp-ThresholdMsg1-RepetitionNumX (X is, for example, an integer greater than or equal to 2)).

[0101] Note that the repetition of Msg1 may be interpreted as the repetition of PRACH. For example, the number of repetitions of Msg1 may be interpreted as the number of PRACH repetitions (PRACH repetition number).

[0102] <Number of repetitions of Msg1 in re-attempts> The random access preamble (e.g., Msg1) may be transmitted with repetition, for example, if the random access procedure is not completed.

[0103] In the case where the preamble is transmitted with repetition, the number of preamble transmissions is counted, and when the counted number of transmissions reaches a threshold, the repetition number is changed. Here, the number of preamble transmissions corresponds to the number of RACH attempts. The counter that counts the number of preamble transmissions is called PREAMBLE_TRANSMISSION_COUNTER. The threshold that is compared with the counted number of transmissions is set by a parameter called preambleTransMax-Msg1-Repetition.

[0104] For example, if either of the following two conditions is met, a set of random access resources associated with the next highest repetition count of Msg1 is selected. In other words, if either of the following two conditions is met, the next highest repetition count of Msg1 is selected as the repetition count. Here, the terms select, change, update, set, determine, etc. may be interchangeable. Note that preambleTransMax-Msg1-Repetition is an integer value equal to or greater than 1. ·PREAMBLE_TRANSMISSION_COUNTER = [preambleTransMax-Msg1-Repetition] + 1 ·PREAMBLE_TRANSMISSION_COUNTER = 2 × [preambleTransMax-Msg1-Repetition] + 1

[0105] Fig. 12 is a diagram showing an example of changing the RACH attempt and the repetition number. Fig. 12 shows RACH opportunities and the number of repetitions in the RACH attempt at each RACH opportunity. The value of PREAMBLE_TRANSMISSION_COUNTER represents the number of RACH attempts, and the value of repK represents the number of repetitions. For example, the RACH attempt corresponding to PREAMBLE_TRANSMISSION_COUNTER=i (i is an integer equal to or greater than 1) is the i-th RACH attempt. Also, the available repetition numbers in Fig. 12 are 2, 4, and 8.

[0106] In the example of Fig. 12, the repetition count of each RACH attempt corresponding to PREAMBLE_TRANSMISSION_COUNTER = 1 through PREAMBLE_TRANSMISSION_COUNTER = preambleTransMax-Msg1-Repetition is 2. The repetition count of a RACH attempt for which PREAMBLE_TRANSMISSION_COUNTER = [preambleTransMax-Msg1-Repetition] + 1 is satisfied increases to "4," which corresponds to the next highest repetition count after "2" among the available repetition counts. Also, the repetition count of a RACH attempt for which PREAMBLE_TRANSMISSION_COUNTER = 2 × [preambleTransMax-Msg1-Repetition] + 1 is satisfied increases to "8," which corresponds to the next highest repetition count after "4" among the available repetition counts.

[0107] As mentioned above, for PRACH repetition, when the number of RACH attempts reaches a certain value, the repetition factor increases to the next highest available repetition factor, which in the above example is [preambleTransMax-Msg1-Repetition] + 1 or 2 × [preambleTransMax-Msg1-Repetition] + 1.

[0108] In a certain RACH attempt (or re-attempt), if random access is successful (for example, when Msg2 etc. is received from the base station and subsequent procedures are completed), then hereafter, RACH re-attempts need not be performed.

[0109] Note that preambleTransMax-Msg1-Repetition used to determine the number of repetitions in RACH re-attempts is included in BWP-UplinkCommon. Note that BWP-UplinkCommon is used to set the common parameters of the uplink BWP. BWP-UplinkCommon is included in, for example, the information element (IE) called BWP-Uplink.

[0110] <RACH Re-attempt for SBFD RA> In RAN2's #127bis, agreement was reached on RACH re-attempts for SBFD RA.

[0111] In one RACH procedure, for re-attempts of PRACH transmission, after a specific number of RACH attempts in the RACH opportunity of SBFD, the UE is allowed to switch to a legacy RACH opportunity. The legacy RACH opportunity may be read as a legacy RO (RACH occasion). The RACH opportunity of SBFD, SBFD-RO, and additional RO may be read as each other.

[0112] Figure 13 is a diagram showing an example of RACH attempts and switching of RACH opportunities. In Figure 13, the relationship between RACH attempts and the types of symbols where RACH attempts are performed is shown.

[0113] As shown in Figure 13, N RACH attempts from the first RACH attempt to the Nth RACH attempt are performed in the SBFD symbol. Then, N+1th and subsequent RACH attempts are performed in the non-SBFD symbol. Here, the RACH attempts in the SBFD symbol correspond to RACH attempts in SBFD RACH opportunities, and the RACH attempts in the non-SBFD symbol correspond to RACH attempts in legacy RACH opportunities.

[0114] That is, in the example of Figure 13, when the number of RACH attempts reaches a certain value, the PRACH in SBFD is switched to the PRACH in non-SBFD. In the example of Figure 13, after N RACH attempts on SBFD RACH opportunities, the UE switches to the legacy RACH opportunity. Here, the certain value may be regarded as N or N+1, where N is an integer equal to or greater than 1.

[0115] <Switching from 2-step RA to 4-step RA> TS 38.321 (e.g., Section 5.1.3a) specifies the following items regarding the switch from 2-step RA to 4-step RA: In the case where the random access procedure is not completed, if msgA-TransMax is applied and PREAMBLE_TRANSMISSION_COUNTER = msgA-TransMax + 1 holds, the RA type is set to 4-step RA.

[0116] The above-mentioned switching from 2-step RA to 4-step RA (eg, fallback) is similar to the RO type switching described using the example of FIG.

[0117] <SBFDにおけるPRACHのリピティション> In RAN1, it has been agreed that the following repetitions of the PRACH are supported: PRACH repetition with additional RO only ·PRCH repetition only in Legacy RO

[0118] In other words, PRACH transmission that repeats preambles across additional RO and legacy RO is not supported.

[0119] <Related Technology 1> As related art, support for switching from a PRACH in SBFD for RACH retry to a PRACH in non-SBFD, and switching from a PRACH in non-SBFD for RACH retry to a PRACH in SBFD is shown. SBFD may be read as an SBFD symbol. Non-SBFD may be read as a non-SBFD symbol.

[0120] <Related Technology 1-1> In Related Art 1-1, switching from a PRACH in SBFD to a non-SBFD PRACH is determined based on a first condition. Switching may be interpreted as a fallback. The first condition is that the number of RACH attempts for a PRACH in SBFD reaches a certain number. The certain number may be interpreted as a threshold. The following options are considered as Related Art 1-1.

[0121] In Related Art 1-1, a threshold is set for switching from SBFD symbols to non-SBFD symbols.

[0122] For example, the threshold value is preambleTransMax included in the additional / separate RACH configuration (RACH configuration for SBFD). The threshold value may be used to determine whether to switch from SBFD symbols to non-SBFD symbols.

[0123] For example, the threshold value may be a new parameter (e.g., sbfd-TransMax) included in the legacy RACH configuration or the RACH configuration for SBFD. The threshold value may be used to determine whether to switch from SBFD symbols to non-SBFD symbols.

[0124] The UE may assume that the threshold is less than or not greater than the preambleTransMax included in the legacy RACH configuration.

[0125] <Related Technology 1-2> In Related Art 1-2, the UE may perform the following operations for switching from an SBFD symbol to a non-SBFD symbol. Specifically, a case where the first RACH attempt is a PRACH transmission in an SBFD symbol will be described. The case where the first RACH attempt is a PRACH transmission in an SBFD symbol is, for example, a case where the PRACH transmission of the first RACH attempt is performed with a valid RO in the SBFD symbol, or a case where the PRACH transmission of the first RACH attempt is performed with a valid RO set by an additional RACH configuration for SBFD.

[0126] For RACH retry, if the value of PREAMBLE_TRANSMISSION_COUNTER is smaller than or not larger than a threshold (preambleTransMax or sbfd-TransMax), the UE determines to transmit a PRACH in an SBFD symbol for RACH retry. The PRACH in the SBFD symbol may be a PRACH in a valid RO in the SBFD symbol, or may be a PRACH in a valid RO configured by the RACH configuration for SBFD.

[0127] For RACH retry, if the value of PREAMBLE_TRANSMISSION_COUNTER is not greater than or less than the threshold (preambleTransMax or sbfd-TransMax), the UE determines to transmit a PRACH in a non-SBFD symbol for RACH retry. The PRACH in a non-SBFD symbol may be a PRACH in a valid RO in a non-SBFD symbol, or may be a PRACH in a valid RO configured by the legacy RACH configuration.

[0128] <Considerations> In legacy PRACH repetition, if a PRACH with multiple repetitions is determined in the first RACH attempt, the UE may maintain or increase the repetition number based on a condition. For example, in this case, the UE may maintain the repetition number in the second and subsequent RACH attempts at the same number as the repetition number in the previous RACH attempt, or may increase the repetition number from the previous RACH attempt based on a condition regarding the number of RACH attempts.

[0129] Also, in legacy PRACH repetition, if a non-repetition PRACH is determined in the first RACH attempt, the UE transmits a non-repetition PRACH in a later RACH retry, which may correspond to the second or subsequent RACH attempts.

[0130] According to the agreement in RAN2#127bis, if the number of RACH attempts reaches a certain value, the UE can switch from additional RO to legacy RO.

[0131] However, the RAN2#127bis agreement does not address the relationship between RO type switching and repetition, so there is room for further discussion regarding RO type switching. For example, there is room for further discussion regarding the behavior of UEs regarding RO type switching when a UE transmits a PRACH with repetition in additional RO.

[0132] For example, if a UE transmits a PRACH with repetition in additional RO, it is worth considering whether the UE can switch to legacy RO for PRACH transmission.

[0133] In the case where the UE transmits a PRACH with repetition in additional RO, if it is not yet determined whether the UE can switch to legacy RO for PRACH transmission, a discrepancy occurs between the base station and the UE regarding the switching of the RO type, and the RO type cannot be switched appropriately, which may result in the random access not being performed appropriately.In this case, a discrepancy occurs between the base station and the UE regarding the relationship between the switching of the RO type and the presence or absence of repetition, which may result in the repetition not being performed appropriately after the RO type is switched, which may result in the random access not being performed appropriately.

[0134] In addition, in a case where a UE transmits a PRACH with repetition in additional RO, if the UE can switch to legacy RO for PRACH transmission, there is room for consideration on how to determine the number of repetitions in legacy RO after switching the RO type.

[0135] When a UE can switch to a legacy RO for PRACH transmission, if the repetition count in the legacy RO after switching the RO type cannot be determined properly, the repetition before and after switching the RO type may not be performed properly, which may result in random access not being performed properly or the resources required for random access increasing.

[0136] Therefore, in this embodiment, when a PRACH with repetition is transmitted in additional RO, the operation of the UE depending on whether the UE supports switching to legacy RO for PRACH transmission, and when the UE supports switching to legacy RO for PRACH transmission, the timing of switching the RO type and the determination of the number of repetitions before and after the switching will be described.

[0137] <Proposal Summary> Proposal 1 and Proposal 2 described below are based on the premise that a preamble, which is an example of a signal related to random access, is transmitted with multiple repetitions in the first RACH attempt. An outline of the proposals is given below. · Proposal 1: RO type switching is not supported for RACH retry with PRACH repetition. Proposal 2: Supports switching of RO type for PRACH repetition during RACH retry. Proposal 2 explains the following points. Proposal 2-1: PRACH repetition count before switching RO type Proposal 2-2: Switching RO type for PRACH repetition Proposal 2-3: PRACH repetition count after switching RO type from SBFD-RO to legacy RO Proposal 2-3A: PRACH repetition count for the first RACH retry in legacy RO after RO type switching when UE switches from SBFD-RO to legacy RO Proposal 2-3B: Maintain or increase PRACH repetition count for later RACH retries in legacy ROs after RO type switch

[0138] <Proposal 1> Proposal 1 assumes that the preamble is transmitted with multiple repetitions in the first RACH attempt, and does not support RO type switching for RACH retries, where RO type switching corresponds to, for example, switching to either the additional RO type or the legacy RO type.

[0139] In the case where Proposal 1 is applied, RO type switching for RACH retries is not supported if the preamble is transmitted with multiple repetitions in the first RACH attempt, or, in other words, in the case where Proposal 1 is applied, RO type switching for RACH retries is supported only if the preamble is transmitted without repetitions in the first RACH attempt.

[0140] The PRACH repetition count may be increased or maintained based on a legacy rule. For example, the UE may determine the PRACH repetition count based on a legacy rule. Note that the legacy rule may be, for example, the rule described above in "Number of repetitions of Msg1 in re-attempts."

[0141] <Variation of Proposal 1> A parameter called preambleTransMax-Msg1-Repetition may be configured separately for the PRACH repetition in the additional RO. That is, the parameter called preambleTransMax-Msg1-Repetition for the PRACH repetition in the additional RO may be configured separately from the parameter called preambleTransMax-Msg1-Repetition for the PRACH repetition in the legacy RO. For example, a new parameter called preambleTransMax-Msg1-Repetition-sbfd-r19 may be configured, and this new parameter may be used to determine whether to maintain or increase the repetition count of the PRACH.

[0142] If preambleTransMax-Msg1-Repetition for the additional RO is not set, the legacy parameter preambleTransMax-Msg1-Repetition may be used. The preambleTransMax-Msg1-Repetition for the additional RO may be called, for example, the above-mentioned preambleTransMax-Msg1-Repetition-sbfd-r19, or may be called by another name.

[0143] The UE does not switch to another RO type regardless of whether the configured number of RACH attempts for RO type switching is reached or not, where RO type switching based on whether the configured number of RACH attempts for RO type switching is reached or not corresponds to the switching exemplified in "RACH retry for SBFD RA" above.

[0144] As described above, Proposal 1 does not support switching to legacy RO for PRACH transmission when the UE transmits a PRACH with repetition in additional RO. That is, in this case, the UE does not switch to legacy RO for PRACH transmission. Proposal 1 can avoid inconsistencies between the base station and the UE regarding the switching of the RO type, thereby enabling appropriate switching of the RO type and appropriate execution of random access. Furthermore, in this case, it can avoid inconsistencies between the base station and the UE regarding the relationship between the switching of the RO type and the presence or absence of repetition, thereby enabling appropriate execution of random access.

[0145] <Proposal 2> Proposal 2 assumes that the preamble is transmitted with multiple repetitions in the first RACH attempt, similar to Proposal 1. Proposal 2 also supports switching of RO types for PRACH repetitions during RACH retries.

[0146] In the case where Proposal 2 is applied, RO type switching is supported for RACH retries when the preamble is transmitted with multiple repetitions in the first RACH attempt. In other words, in the case where Proposal 2 is applied, RO type switching is supported for RACH retries whether the preamble is transmitted without repetition in the first RACH attempt or whether the preamble is transmitted with multiple repetitions in the first RACH attempt. In other words, in the case where Proposal 2 is applied, RO type switching is supported for RACH retries regardless of whether the preamble is transmitted without repetition or with multiple repetitions in the first RACH attempt.

[0147] <Proposal 2-1> Proposal 2-1 describes the determination of the PRACH repetition count before switching the RO type.

[0148] In Proposal 2-1, the PRACH repetition count may be increased or maintained based on a legacy rule. For example, the UE may determine the PRACH repetition count based on a legacy rule. Note that the legacy rule may be, for example, the rule shown in "Number of repetitions of Msg1 in re-attempts" above.

[0149] <Variation of Proposal 2-1> A parameter called preambleTransMax-Msg1-Repetition may be configured separately for the PRACH repetition in the additional RO. That is, the parameter called preambleTransMax-Msg1-Repetition for the PRACH repetition in the additional RO may be configured separately from the parameter called preambleTransMax-Msg1-Repetition for the PRACH repetition in the legacy RO. For example, a new parameter called preambleTransMax-Msg1-Repetition-sbfd-r19 may be configured, and this new parameter may be used to determine whether to maintain or increase the repetition count of the PRACH.

[0150] When the preambleTransMax-Msg1-Repetition for the additional RO is not set, the legacy parameter preambleTransMax-Msg1-Repetition may be used. The preambleTransMax-Msg1-Repetition for the additional RO may be called, for example, the above-mentioned preambleTransMax-Msg1-Repetition-sbfd-r19 or may be called by another name.

[0151] When the parameters used to determine the PRACH repetition count before switching the RO type are set separately for PRACH repetition in the additional RO and for PRACH repetition in the legacy RO, appropriate repetition counts can be determined for PRACH repetition in the additional RO and for PRACH repetition in the legacy RO.

[0152] <Proposal 2-2> Proposal 2-2 describes switching of RO type for PRACH repetition.

[0153] In Proposal 2-2, when the configured number of RACH attempts for switching the RO type is reached, the UE may switch to another RO type. Alternatively, when the configured number of RACH attempts for switching the RO type is reached, the UE should switch to another RO type. Note that the configured number of RACH attempts for switching the RO type is, for example, the number configured in the RAN2 agreement shown in the above-mentioned "RACH Retry for SBFD RA" or the like. The configured number of RACH attempts for switching the RO type corresponds to a threshold that is compared with the number of RACH attempts to determine whether to switch the RO type. The configured number of RACH attempts for switching the RO type is, for example, configured by a parameter called preambleTransMax-sbfd.

[0154] <Variation of Proposal 2-2> The number of RACH attempts for RO type switching may be configured separately for PRACH without repetition and for PRACH with repetition.

[0155] The first parameter (e.g., preambleTransMax-sbfd) is set for the number of RACH attempts without PRACH repetition in SBFD-RO (i.e., additional RO), and the second parameter (e.g., preambleTransMax-sbfd-repetition) is set for the number of RACH attempts with PRACH repetition in SBFD-RO.

[0156] In this embodiment, the first parameter and the second parameter are referred to as "preambleTransMax-sbfd" and "preambleTransMax-sbfd-repetition," respectively, but the first parameter and the second parameter are not limited to these names. For example, as shown in the above-mentioned "Related Art 1," names such as "preambleTransMax" or "sbfd-TransMax" may be used.

[0157] For example, when the UE transmits a PRACH without repetition in additional RO in the first RACH attempt, the UE uses the first parameter to determine whether to switch (or fall back) to legacy RO. For example, when the number of RACH attempts reaches a number set based on the first parameter, the UE switches the RO type to legacy RO. Note that the decision to switch may be considered as a decision on the timing to switch. The number set based on the first parameter may be the number indicated by the first parameter.

[0158] For example, when the UE transmits a PRACH with repetition in additional RO in the first RACH attempt, the UE uses the second parameter to determine whether to switch (fallback) to legacy RO. For example, when the number of RACH attempts reaches a number set based on the second parameter, the UE switches the RO type to legacy RO. The number set based on the second parameter may be the number indicated by the second parameter.

[0159] If the second parameter is not configured, the UE uses the first parameter to determine the switching (fallback) of the RO type.

[0160] By setting the number of RACH attempts for switching the RO type separately for the PRACH without repetition and for the PRACH with repetition, the RO type can be switched at the appropriate timing for each of the PRACH without repetition and the PRACH with repetition.

[0161] <Proposal 2-3> Proposal 2-3 explains how to determine the PRACH repetition count after switching the RO type from SBFD-RO (in other words, additional RO) to legacy RO. Hereinafter, Proposal 2-3A shows the PRACH repetition count for the first RACH retry in legacy RO after RO type switching, and Proposal 2-3B shows the PRACH repetition count for the RACH retry after the first RACH retry in legacy RO after RO type switching.

[0162] <Proposal 2-3A> When the UE switches from SBFD-RO to legacy RO, at least one of the following options shall be applied for the first RACH retry in legacy RO after RO type switching: That is, for the PRACH repetition count in the first RACH retry in legacy RO after RO type switching, at least one of the following options shall be applied:

[0163] (Option A-1) The rule for determining whether to maintain or increase the PRACH repetition count in the first RACH retry in a legacy RO after switching the RO type is the same as that in the legacy RO. That is, switching the RO type does not affect the maintenance / increment of the PRACH repetition count. Note that the legacy rule may be, for example, the rule shown in "Number of repetitions of Msg1 in re-attempts" above.

[0164] (Option A-2) The PRACH repetition number in the first RACH retry in legacy RO after RO type switching is the same as the PRACH repetition number in the last RACH attempt in SBFD-RO.

[0165] (Option A-3) The PRACH repetition number for the first RACH retry in the legacy RO after RO type switching is reduced to the next lower repetition number (greater than 1) if the next lower repetition number is available. Note that the next lower repetition number corresponds to, for example, a PRACH repetition number lower than the PRACH repetition number for the RACH attempt one before the first RACH retry in the legacy RO after RO type switching. The RACH attempt one before the first RACH retry in the legacy RO after RO type switching may be the last RACH attempt in the SBFD-RO.

[0166] In Option A-3, a case where the next lower repetition factor can be used will be described. For example, if the available repetition factors are 2, 4, and 8, and the PRACH repetition factor in the RACH attempt immediately before the first RACH retry in the legacy RO after the RO type switch is "4," the available repetition factors include "2," which is the next lower repetition factor after "4." This case corresponds to the case where the next lower repetition factor can be used.

[0167] In option A-3, if the available repetition factors are 2, 4, and 8, and the PRACH repetition factor in the RACH attempt immediately before the first RACH retry in the legacy RO after the RO type switch is "2," the available repetition factors do not include the next lowest repetition factor after "2." This corresponds to the case where the next lowest repetition factor is unavailable. In option A-3, if the next lowest repetition factor is unavailable, another option (e.g., at least one of options A-1 to A-8 excluding option A-3) may be applied.

[0168] (Option A-4) The PRACH repetition number for the first RACH retry in the legacy RO after RO type switching is increased to the next higher repetition number if the next higher repetition number is available. For example, the next higher repetition number corresponds to a PRACH repetition number higher than the PRACH repetition number for the RACH attempt one before the first RACH retry in the legacy RO after RO type switching. The RACH attempt one before the first RACH retry in the legacy RO after RO type switching may be the last RACH attempt in the SBFD-RO.

[0169] In Option A-4, a case where the next higher repetition factor is available will be described. For example, if the available repetition factors are 2, 4, and 8, and the PRACH repetition factor in the RACH attempt immediately before the first RACH retry in the legacy RO after the RO type switch is "4," the available repetition factors include "8," which is the next higher repetition factor after "4." This case corresponds to the case where the next higher repetition factor is available.

[0170] In option A-4, if the available repetition factors are 2, 4, and 8, and the PRACH repetition factor in the RACH attempt immediately before the first RACH retry in the legacy RO after the RO type switch is "8," the available repetition factors do not include the next higher repetition factor after "8." This corresponds to the case where the next higher repetition factor is unavailable. In option A-4, if the next higher repetition factor is unavailable, another option (e.g., at least one of options A-1 to A-8 excluding option A-4) may be applied.

[0171] (Option A-5) The PRACH repetition number for the first RACH retry in the legacy RO after RO type switching is reset to the lowest repetition number for PRACH repetition in the legacy RO (and a number greater than 1). For example, if the available repetition numbers are 2, 4, and 8, the PRACH repetition number for the first RACH retry in the legacy RO after RO type switching is reset to 2.

[0172] (Option A-6) The PRACH repetition number for the first RACH retry in the legacy RO after RO type switching is reset to the highest repetition number for PRACH repetition in the legacy RO (and a number greater than 1). For example, if the available repetition numbers are 2, 4, and 8, the PRACH repetition number for the first RACH retry in the legacy RO after RO type switching is reset to 8.

[0173] (Option A-7) The UE reselects the PRACH repetition number for the legacy RO based on the RSRP threshold, i.e., rsrp-ThresholdMsg1-RepetitionNum2 / 4 / 8. The reselection method may be the same as the method described in "Repetition number of Msg1 for initial attempt" above.

[0174] (Option A-8) The PRACH repetition count is reset to 1. That is, no PRACH repetition is performed in the legacy RO after switching the RO type.

[0175] Next, the number of repetitions when each of the above-mentioned options A-1 to A-8 is applied will be explained using the drawings.

[0176] FIG. 14 is a diagram illustrating examples of each option of Proposal 2-3A. FIG. 14 illustrates the type of RO and the repetition count of RACH attempts for each RO. FIG. 14 also illustrates an example in which the configured number of RACH attempts for switching RO type is "4," the configured number of RACH attempts for increasing the repetition count of PRACH is "2," and the configured repetition counts for legacy RO and additional RO are selected from the set of "2, 4, 8," respectively. The configured number of RACH attempts for switching RO type is represented, for example, as preambleTransMax-sbfd. The configured number of RACH attempts for increasing the repetition count of PRACH is represented as preambleTransMax-Msg1-Repetition.

[0177] In addition, as shown in the variation of Proposal 2-2, if the number of RACH attempts for switching the RO type is set separately for PRACH without repetition and for PRACH repetition, and the parameter set for the number of RACH attempts with PRACH repetition in additional RO is called preambleTransMax-sbfd-repetition, preambleTransMax-sbfd in Figure 14 may be replaced with preambleTransMax-sbfd-repetition.

[0178] In Fig. 14, the first and second RACH attempts in additional RO are performed with a repetition count of 2. Then, in the third RACH attempt, since "PREAMBLE_TRANSMISSION_COUNTER = preambleTransMax-Msg1-Repetition+1" is satisfied, the repetition count is increased to "4," which is the next highest repetition count after "2" among {2, 4, 8}.

[0179] Also, in the fifth RACH attempt, "PREAMBLE_TRANSMISSION_COUNTER = preambleTransMax-sbfd+1" is satisfied, so the RACH opportunity is switched from additional RO to legacy RO. In other words, the fifth RACH attempt corresponds to the first RACH retry in legacy RO after the RO type switch. The following shows how to determine the repetition count in the fifth RACH attempt when each option is applied.

[0180] In Option A-1, the rule for determining the PRACH repetition count is the same as in Legacy. Therefore, when Option A-1 is applied, the repetition count increases to "8" which is the next highest repetition count after "4" among {2, 4, 8}, because "PREAMBLE_TRANSMISSION_COUNTER=2*preambleTransMax-Msg1-Repetition+1" is satisfied at the fifth RACH attempt.

[0181] In option A-2, the PRACH repetition number is the same as the PRACH repetition number for the last RACH attempt in SBFD-RO. Therefore, when option A-2 is applied, the repetition number for the fifth RACH attempt is the same as the repetition number for the fourth RACH attempt, which corresponds to the last RACH attempt in SBFD-RO (i.e., additional RO). In other words, the repetition number for the fifth RACH attempt is "4."

[0182] In option A-3, the PRACH repetition number is reduced to the next lower repetition number (and a number greater than 1) if the next lower repetition number is available. Therefore, when option A-3 is applied, the repetition number of the fifth RACH attempt is reduced to "2", which is the next lower repetition number after the repetition number of the fourth RACH attempt.

[0183] In option A-4, the PRACH repetition number is increased to the next higher repetition number if the next higher repetition number is available. Therefore, when option A-4 is applied, the repetition number of the fifth RACH attempt is increased to "8", which is the next higher repetition number after the repetition number of the fourth RACH attempt.

[0184] In option A-5, the PRACH repetition count is reset to the lowest repetition count (greater than 1) for PRACH repetition in the legacy RO. Therefore, when option A-5 is applied, the repetition count for the fifth RACH attempt is reset to "2", which corresponds to the lowest repetition count among 2, 4, and 8 available for PRACH repetition in the legacy RO.

[0185] In option A-6, the PRACH repetition count is reset to the highest repetition count (greater than 1) for PRACH repetition in the legacy RO. Therefore, when option A-6 is applied, the repetition count for the fifth RACH attempt is reset to "8", which corresponds to the highest repetition count available for PRACH repetition in the legacy RO: 2, 4, and 8.

[0186] In option A-7, the UE reselects the PRACH repetition factor in the legacy RO based on the RSRP threshold. Therefore, when option A-7 is applied, the repetition factor for the fifth RACH attempt is reselected from among the available repetition factors for PRACH repetition in the legacy RO: 2, 4, and 8.

[0187] In option A-8, the PRACH repetition count is reset to 1. Therefore, when option A-8 is applied, the repetition count for the fifth RACH attempt is reset to "1".

[0188] <Variation of Proposal 2-3A> Different combinations of options may be possible based on rules.

[0189] For example, if the PRACH repetition count in the last RACH attempt in the additional RO is greater than the highest repetition count available in the legacy RO, option A-6 applies; otherwise, options A-1 / A-2 apply.

[0190] Any other combination of options A-1 to A-8 is possible.

[0191] Which options apply may be defined by the specification, configured by the RRC, or indicated by the SIB.

[0192] In Proposal 2-3A, the UE determines the repetition count for the first RACH retry in legacy RO after switching the RO type based on at least one of the legacy rule, the number of RACH attempts, the PRACH repetition count for the last RACH attempt in SBFD-RO, one or more available repetition counts, and the result of comparing the RSRP with a threshold. The PRACH repetition count for the last RACH attempt in SBFD-RO is used in Options A-2 to A-4. The available repetition counts are used in Options A-5 to A-6. The result of comparing the RSRP with a threshold is used in Option A-7. Note that the last RACH attempt in SBFD-RO is an example of a RACH attempt in SBFD-RO before switching the RO type.

[0193] <Proposal 2-3B> Proposal 2-3B describes later RACH retries in a legacy RO after an RO type switch. Here, later RACH retries refer to RACH retries after the first RACH retry in a legacy RO after an RO type switch. At least one of the following options is applied to the number of PRACH repetitions in RACH retries after the first RACH retry in a legacy RO after an RO type switch:

[0194] (Option B-1) The same PRACH repetition count as the repetition count for the first RACH retry in a legacy RO after an RO type switch is applied to the PRACH repetition count for RACH retries after the first RACH retry in a legacy RO after an RO type switch, without any further PRACH repetition count increments.

[0195] (Option B-2) The PRACH repetition count for RACH retries after the first RACH retry in the legacy RO after RO type switching is maintained or increased according to the legacy rule based on the number of RACH retries and the configured number of RACH attempts for increasing the repetition count, where the configured number of RACH attempts for increasing the repetition count is preambleTransMax-Msg1-Repetition. The legacy rule may be, for example, the rule shown in "Number of repetitions of Msg1 in re-attempts" above.

[0196] In option B-2, if either of the following equations (B-2-1) or (B-2-2) holds, the UE selects the next higher repetition factor if it is available. If neither of the following two equations holds, the repetition factor is maintained. ·PREAMBLE_TRANSMISSION_COUNTER = [preambleTransMax-Msg1-Repetition] + 1 (B-2-1) ·PREAMBLE_TRANSMISSION_COUNTER = 2 × [preambleTransMax-Msg1-Repetition] + 1 (B-2-2)

[0197] (Option B-3) The PRACH repetition count for RACH retries after the first RACH retry in the legacy RO after the RO type switch is maintained or increased according to the legacy rule based on the number of RACH retries in the legacy RO and the configured number of RACH attempts for increasing the repetition count, where the configured number of RACH attempts for increasing the repetition count is preambleTransMax-Msg1-Repetition. Note that the number of RACH retries in the legacy RO may not include the number of RACH retries in the additional RO.

[0198] In option B-3, if either of the following equations (B-3-1) or (B-3-2) holds, the UE selects the next higher repetition factor if it is available. If neither of the following two equations holds, the repetition factor is maintained. ·PREAMBLE_TRANSMISSION_COUNTER - preambleTransMax-sbfd = [preambleTransMax-Msg1-Repetition] + 1 (B-3-1) ·PREAMBLE_TRANSMISSION_COUNTER - preambleTransMax-sbfd = 2 ×[preambleTransMax-Msg1-Repetition] + 1 (B-3-2)

[0199] Note that a parameter called preambleTransMax-sbfd indicates the set number of RACH attempts for switching the RO type. For example, preambleTransMax-sbfd is a parameter that sets a threshold for switching as shown in the above-mentioned "RACH Retry for SBFD RA." This parameter is shown in Proposal 2-2. This parameter is set separately from the value for PRACH repetition for switching the RO type. Here, the value for PRACH repetition for switching the RO type may be, for example, preambleTransMax-sbfd-repetition shown in Proposal 2-2.

[0200] Note that when option B-3 is applied, the counted value of PREAMBLE_TRANSMISSION_COUNTER may be reset to 0 when the RO type is switched. In this case, PREAMBLE_TRANSMISSION_COUNTER indicates 1 for the first RACH attempt in the legacy RO and indicates 2 for the second RACH attempt in the legacy RO. When the counted value of PREAMBLE_TRANSMISSION_COUNTER is reset to 0 when the RO type is switched, for example, when either equation (B-2-1) or equation (B-2-2) holds, the UE selects the next higher repetition factor if the next higher repetition factor is available.

[0201] Note that, when Option B-3 is applied, a counter for counting RACH retries in a legacy RO may be configured separately from PREAMBLE_TRANSMISSION_COUNTER. The counter for counting RACH retries in a legacy RO indicates 1 for the first RACH attempt in the legacy RO and indicates 2 for the second RACH attempt in the legacy RO. When the counter for counting RACH retries in a legacy RO is configured separately from PREAMBLE_TRANSMISSION_COUNTER, for example, PREAMBLE_TRANSMISSION_COUNTER on the left-hand side of Equation (B-2-1) and Equation (B-2-2) is replaced with "the value of the counter for counting RACH retries in the legacy RO." If either of the two equations after this replacement is satisfied and the next higher repetition factor is available, the UE selects the next higher repetition factor.

[0202] (Option B-4) The PRACH repetition count is equal to 1, i.e., no PRACH repetition is performed in the legacy RO after switching the RO type.

[0203] Option B-4 will likely be applied in conjunction with Option A-8 of Proposal 2-3A, but may also be combined with other options in Proposal 2-3A.

[0204] FIG. 15 is a diagram illustrating examples of Options B-1, B-2, and B-3 of Proposal 2-3B. FIG. 15 illustrates the type of RO and the repetition count of RACH attempts for each RO. FIG. 15 also illustrates an example in which the configured number of RACH attempts for switching the RO type is "4," the configured number of RACH attempts for increasing the repetition count of the PRACH is "6," and the configured repetition counts for the legacy RO and the additional RO are selected from the set of "2, 4, 8," respectively. The configured number of RACH attempts for switching the RO type is represented, for example, as "preambleTransMax-sbfd." The configured number of RACH attempts for increasing the repetition count of the PRACH is represented as "preambleTransMax-Msg1-Repetition."

[0205] 15, the first to fourth RACH attempts in the additional RO are performed with a repetition count of 2. Then, in the fifth RACH attempt, the RACH opportunity is switched from the additional RO to the legacy RO because "PREAMBLE_TRANSMISSION_COUNTER = preambleTransMax-sbfd+1" is satisfied. In other words, the fifth RACH attempt corresponds to a RACH retry in the legacy RO after the RO type switch.

[0206] For the fifth RACH attempt, Option A-1 or A-2 of Proposal 2-3A described above is applied. In Option A-1, the rule for determining the PRACH repetition number is the same as that in the legacy system. Therefore, when Option A-1 is applied, the repetition number for the fifth RACH attempt is "2" because preambleTransMax-Msg1-Repetition=6. In Option A-2, the PRACH repetition number is the same as that for the last RACH attempt in SBFD-RO. Therefore, when Option A-2 is applied, the repetition number for the fifth RACH attempt is the same as that for the fourth RACH attempt, which is the last RACH attempt in SBFD-RO (i.e., additional RO). In other words, the repetition number for the fifth RACH attempt is "2".

[0207] FIG. 15 shows the repetition counts when options B-1 to B-3 are applied to the sixth and subsequent RACH attempts in the case where the repetition count for the fifth RACH attempt is "2."

[0208] In option B-1, the PRACH repetition count is the same as the repetition count for the first RACH retry in the legacy RO after switching the RO type, without any further increment of the PRACH repetition count. Therefore, when option B-1 is applied, the repetition count for the sixth and subsequent RACH attempts is "2", which corresponds to the repetition count for the first RACH retry in the legacy RO.

[0209] In option B-2, the PRACH repetition factor is maintained or increased according to the legacy rule based on the number of RACH retries and the configured number of RACH attempts for increasing the repetition factor. For example, when option B-2 is applied, the repetition factor for the sixth RACH attempt is "2" because the above-described formula (B-2-1) holds for the seventh RACH attempt, and the repetition factor for the seventh RACH attempt is changed to "4," which corresponds to the next highest repetition factor after two. The repetition factors for the eighth through twelfth RACH attempts are also "4." Although not shown in the figure, the repetition factor for the thirteenth RACH attempt is changed to "8," which corresponds to the next highest repetition factor after four, because the above-described formula (B-2-2) holds for the thirteenth RACH attempt.

[0210] In option B-3, the PRACH repetition count is maintained or increased according to the legacy rule based on the number of RACH retries in the legacy RO and the configured number of RACH attempts for increasing the repetition count. For example, when option B-3 is applied, the repetition count for the 7th to 10th RACH attempts is "2" and the repetition count for the 11th RACH attempt is "4" because equation (B-3-1) holds for the 11th RACH attempt. The repetition count for the 12th to 16th RACH attempts is also "4." Although not shown in the figure, the repetition count for the 17th RACH attempt is changed to "8," which corresponds to the next highest repetition count after 4, because equation (B-3-2) holds for the 17th RACH attempt.

[0211] FIG. 16 is a diagram illustrating an example in which Option B-4 of Proposal 2-3B is applied. FIG. 16 illustrates an example in which Option B-4 of Proposal 2-3B is applied together with Option A-8 of Proposal 2-3A. FIG. 16 illustrates the type of RO and the repetition count of RACH attempts for each RO. FIG. 16 also illustrates an example in which the configured number of RACH attempts for switching RO type is "4," the configured number of RACH attempts for increasing the repetition count of PRACH is "6," and the configured repetition counts for legacy RO and additional RO are selected from the set of "2, 4, 8," respectively. The configured number of RACH attempts for switching RO type is represented, for example, as preambleTransMax-sbfd. The configured number of RACH attempts for increasing the repetition count of PRACH is represented as preambleTransMax-Msg1-Repetition.

[0212] 16, the first to fourth RACH attempts in the additional RO are performed with a repetition count of 2. Then, in the fifth RACH attempt, the RACH opportunity is switched from the additional RO to the legacy RO because "PREAMBLE_TRANSMISSION_COUNTER = preambleTransMax-sbfd+1" is satisfied. In other words, the fifth RACH attempt corresponds to a RACH retry in the legacy RO after the RO type switch.

[0213] For the fifth RACH attempt, option A-8 of proposal 2-3A above is applied. In option A-8, the PRACH repetition count is reset to 1. Therefore, if option A-8 is applied, the repetition count for the fifth RACH attempt is reset to "1".

[0214] FIG. 16 shows the repetition count when option B-4 is applied to the sixth and subsequent RACH attempts in the case where the repetition count for the fifth RACH attempt is "1."

[0215] In option B-4, the PRACH repetition count is equal to 1. Therefore, exemplarily, when option B-4 is applied, the repetition counts of the seventh and subsequent RACH attempts are each "1".

[0216] Although FIG. 16 shows an example in which both option A-8 and option B-4 are applied, the combination of options is not limited to this.

[0217] As described above, Proposal 2 supports switching to legacy RO for PRACH transmission when the UE transmits a PRACH with repetition in additional RO. That is, in this case, the UE switches to legacy RO for PRACH transmission. Proposal 2 prevents inconsistency between the base station and the UE regarding the switching of the RO type, thereby enabling appropriate switching of the RO type and appropriate execution of random access. Furthermore, in this case, it prevents inconsistency between the base station and the UE regarding the relationship between the switching of the RO type and the presence or absence of repetition, thereby enabling appropriate execution of random access.

[0218] Furthermore, according to Proposal 2-1, in the case where a PRACH with repetition is transmitted in additional RO, the number of PRACH repetitions in the RACH attempt before switching the RO type can be appropriately determined, so that random access with repetition can be performed appropriately.

[0219] Furthermore, according to Proposal 2-2, the RO type for PRACH repetition can be switched at an appropriate timing, so that the RO type can be switched appropriately and random access can be performed appropriately.

[0220] Furthermore, according to Proposal 2-3, in the case where a PRACH with repetition is transmitted in additional RO, the number of PRACH repetitions for the first RACH retry after switching the RO type and for the RACH retry after the first RACH retry can be appropriately determined, so that random access with repetition can be appropriately performed.

[0221] <Variations of this embodiment> The UE may expect the same PRACH repetition factor to be configured in the legacy RO and the additional RO. For example, if the repetition factor configured for the PRACH repetition in the legacy RO is in the set {2, 4, 8}, the UE may expect the repetition factor to be configured in the set {2, 4, 8} for the PRACH repetition in the additional RO.

[0222] The UE may expect different PRACH repetition factors to be configured for the legacy RO and the additional RO. For example, if the repetition factors configured for the PRACH repetition in the legacy RO are in the set {2, 4, 8}, the UE may expect the repetition factors to be configured for the PRACH repetition in the additional RO to be in the set {2, 4, 8, 16}.

[0223] The UE may expect the highest repetition number in the additional RO to be no smaller than the highest repetition number in the legacy RO, or the UE may expect the highest repetition number in the additional RO to be no larger than the highest repetition number in the legacy RO.

[0224] Any two or more of the above proposals or options within each proposal may be combined, and any two or more of the above proposals or options within each proposal may be dynamically or semi-persistently switched.

[0225] The above proposals may be applied to UEs in connected mode or to UEs in RRC idle mode.

[0226] Each of the above proposals may be applied to either CBRA or CFRA.

[0227] Each of the options in the above proposals may be applied to UEs in connected mode or to UEs in RRC idle mode.

[0228] Different proposals or different options of a proposal may be applied to RACH configuration option 1 and RACH configuration option 2. Here, RACH configuration option 1 is a configuration option without additional RACH repetition for SBFD, and RACH configuration option 2 is an option for additional RACH configuration for SBFD.

[0229] Any combination of the options in Proposal 1, Proposal 2-1, Proposal 2-2, and Proposal 2-3 may be possible.

[0230] (Combined with options) In each proposal of the present disclosure, which proposal applies or which option or alternative is used may be determined by the following: - Set by upper layer parameters Determined by related higher level parameters Indicated in MAC CE or DCI Determined based on UE capabilities - Listed in the specifications - Determined based on the conditions stated in the specifications Determined by higher layer parameters / MAC CE / DCI configuration and reported UE capabilities (combination of the above decisions)

[0231] In each proposal in this disclosure, multiple options and alternatives may be combined into a single option / alternative, and throughout the proposals, the measured reference signal (RS) will be the QCL source RS in the active / indicated TCI state.

[0232] (Signal from NW to UE) In this disclosure, the UE may receive the following types of information from the network (NW): Also, throughout the proposal, the network (NW) may be referred to as a gNB. Information via higher layer signaling (e.g., RRC messages / LPP (LTE propositioning protocol) messages) MAC CE Subheader with new LCID in the subheader Extending an existing MAC CE (e.g., introducing a new octet) DCI DCI Field: Existing DCI field or newly introduced DCI field RNTI: DCI with CRC scrambled by the existing RNTI or the newly introduced RNTI DCI Format: Existing DCI format or newly introduced DCI format Combination of the above information

[0233] In the present disclosure, the UE may receive information from the network (NW) in the following periodic format: Option 1: Receive periodic updates Option 2: Semi-persistent reception of information (triggered by UE or gNB instructions) Option 3: Aperiodic information reception (triggered by UE or gNB instructions)

[0234] In the present disclosure, the UE may receive information from the network (NW) as the following QCL rules: QCL Type A QCL Type B QCL Type C QCL Type D

[0235] In this disclosure, the QCL resource RS for each QCL type may be configured as follows: SSB (SS / PBCH Block) CSI-RS with / without repetition ·TRS(tracking reference signal) PDCCH / PDSCH DMRS

[0236] In the present disclosure, information from the network (NW) is set / indicated as follows: ·UE common / UE only Cell specific / Cell common Per UE / CC / BWP / band / cell / CG

[0237] (Signal from UE to NW) In this disclosure, the UE may report the following types of information to the network (NW): Also, throughout the proposal, the network (NW) may be referred to as a gNB. Information via higher layer signaling (e.g. RRC message / LPP message) MAC CE Subheader with new LCID in the subheader Extending an existing MAC CE (e.g., introducing a new octet) UCI UCI on PUCCH or PUSCH Combination of the above information

[0238] In the present disclosure, the UE may report information to the network (NW) in a periodic manner as follows: Option 1: Send information periodically Option 2: Semi-persistent information transmission (triggered by UE or gNB instruction) Option 3: Aperiodic information transmission (triggered by UE or gNB instructions)

[0239] <UE capability> The UE capability indicating the capability of the terminal may include the following information indicating the capability of the terminal. For example, the following new UE capability and report signaling (and RRC configuration) may be defined. Note that the information indicating the capability of the terminal may correspond to information defining the capability of the terminal. The UE may report the following information indicating the capabilities of the terminal to the gNB: ·Device capabilities for each proposal ·Ability to implement each option or combination of options in each proposal · Capabilities for each alternative or combination of alternatives in each proposal The UE may report information indicating the above-mentioned terminal capabilities for each frequency to the gNB. · Capabilities for UE / FR1 / FR2 / FR2-1 / FR2-2 / FR3 / SCS / band / BC / FC / FSPC etc. The UE may report information indicating the above terminal capabilities for each cell to the gNB. Capabilities for each UE / cell / TDD / FDD, etc.

[0240] The above UE capabilities and the configuration of this proposal are closely related, and if the functions related to each option in each proposal depend on the UE capabilities, the gNB may select or enable the functions related to each option based on the capabilities reported by the UE.

[0241] Next, the configurations of the gNB100 and the UE200 will be described. Note that the configurations of the gNB100 and the UE200 described below are examples of functions related to the present embodiment. The gNB100 and the UE200 may have functions not shown. Furthermore, the functional divisions and / or names of the functional units are not limited as long as the functions perform the operations related to the present embodiment.

[0242] <Base station configuration> Fig. 17 is a block diagram showing an example of the configuration of a base station 100 (gNodeB (gNB) 100) according to this embodiment. The gNB 100 includes, for example, a transmitter 101, a receiver 102, and a controller 103. The gNB 100 communicates with a UE 200 (see Fig. 18) wirelessly.

[0243] The transmitter 101 transmits a downlink (DL) signal to the UE 200. For example, under the control of the controller 103, the transmitter 101 transmits a DL signal (for example, the above-mentioned RRC, SIB, MAC CE, DCI, notification, confirmation, etc.).

[0244] The DL signal may include, for example, a downlink data signal and control information (e.g., Downlink Control Information (DCI)). The DL signal may also include information indicating scheduling related to signal transmission by the UE 200 (e.g., an UL grant). The DL signal may also include control information of higher layers (e.g., control information of Radio Resource Control (RRC)). The DL signal may also include a reference signal.

[0245] The channels used for transmitting DL signals include, for example, a downlink data channel and a downlink control channel. For example, the downlink data channel may include a PDSCH (Physical Downlink Shared Channel), and the downlink control channel may include a PDCCH (Physical Downlink Control Channel). For example, the gNB 100 transmits downlink control information to the UE 200 using the PDCCH and transmits downlink data signals using the PDSCH.

[0246] The reference signal included in the DL signal may include at least one of a demodulation reference signal (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 DMRS and PTRS are used for demodulating downlink data signals and are transmitted using the PDSCH.

[0247] The receiver 102 receives an uplink (UL) signal transmitted from the UE 200. For example, under the control of the controller 103, the receiver 102 receives an UL signal (for example, the above-mentioned request, notification, etc.).

[0248] The transmitting unit 101 and the receiving unit 102 may be collectively referred to as a communication unit.

[0249] The control unit 103 controls the communication operations of the gNB 100, including the transmission processing of the transmission unit 101 and the reception processing of the reception unit 102. For example, the control unit 103 performs operations other than the transmission and reception described in the above embodiments (note that these operations may be performed by the reception unit 102 and / or the transmission unit 101).

[0250] 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.

[0251] For example, the control unit 103 allocates resources (or channels) used for transmitting and receiving DL signals and / or resources used for transmitting and receiving UL signals based on a signal (e.g., data and control information, etc.) received from the UE 200 and / or data and control information, etc. acquired from an upper layer. Information on the allocated resources may be included in control information transmitted to the UE 200.

[0252] <Device configuration> 18 is a block diagram showing an example of the configuration of UE 200 according to the present embodiment. UE 200 includes, for example, a receiving unit 201, a transmitting unit 202, and a control unit 203. UE 200 communicates with gNB 100, for example, by radio.

[0253] The transmitter 202 transmits an UL signal to the gNB 100. For example, the transmitter 202 transmits the UL signal under the control of the controller 203. For example, the transmitter 202 may transmit an MsgA PRACH in a valid MsgA RO determined by the controller 203, and may transmit an MsgA PUSCH in a valid MsgA PO determined by the controller 203.

[0254] The UL signal may include, for example, an uplink data signal and control information (e.g., UCI). For example, information related to the processing capability of the UE 200 (e.g., UE capability) may be included. The UL signal may also include a reference signal.

[0255] The channels used for transmitting UL signals include, for example, an uplink data channel and an uplink control channel. For example, the uplink data channel includes a PUSCH (Physical Uplink Shared Channel), and the uplink control channel includes a PUCCH (Physical Uplink Control Channel). For example, the UE 200 transmits uplink control information to the gNB 100 using the PUCCH and transmits an uplink data signal using the PUSCH.

[0256] The reference signals included in the UL signal may include, for example, at least one of DMRS, PTRS, CSI-RS, SRS, and PRS. For example, the reference signals such as DMRS and PTRS are used for demodulating the uplink data signal and are transmitted using an uplink channel (for example, PUSCH).

[0257] The receiving unit 201 and the transmitting unit 202 may be collectively referred to as a communication unit.

[0258] The control unit 203 controls communication operations of the UE 200, including reception processing in the receiving unit 201 and transmission processing in the transmitting unit 202. For example, the control unit 203 performs operations other than the transmission and reception described in the above embodiments (note that these operations may be performed by the receiving unit 201 and / or the transmitting unit 202).

[0259] For example, the control unit 203 acquires information such as data and control information from a higher 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 higher layer.

[0260] For example, the control unit 203 controls transmission of information to be fed back to the gNB 100. The information to be fed back to the gNB 100 may include, for example, HARQ-ACK, Channel State Information (CSI), or a Scheduling Request (SR). The information to be fed back to the gNB 100 may be included in UCI.

[0261] Here, for example, the control unit 203 of the UE 200 sets the type of repetition opportunity based on whether or not switching of the type of repetition opportunity of the random access signal (e.g., preamble or Msg1) is supported. For example, the type of repetition opportunity of the random access signal may be the above-mentioned legacy RO or additional RO. For example, if the control unit 203 does not support switching of the type of repetition opportunity of the random access signal, it does not switch the type of repetition opportunity. Also, if the control unit 203 supports switching of the type of repetition opportunity of the random access signal, it switches the type at a specific opportunity. The communication unit transmits a signal at an opportunity of the type set by the control unit 203.

[0262] <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 the single device or multiple devices with software.

[0263] Functions include, but are not limited to, judgment, determination, judgment, calculation, computation, processing, derivation, investigation, search, confirmation, reception, transmission, output, access, resolution, selection, election, establishment, comparison, assumption, expectation, consideration, broadcasting, notifying, communicating, forwarding, configuring, reconfiguring, allocation, 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.

[0264] For example, a base station, a terminal, etc. according to an embodiment of the present disclosure may function as a computer that performs processing of the communication method of the present disclosure. Figure 19 is a diagram showing an example of the hardware configuration of a base station and a terminal according to an embodiment of the present disclosure. The gNB 100 and UE 200 described above may be physically configured as a computer device including a processor 1001, a memory 1002, a storage 1003, a communication device 1004, an input device 1005, an output device 1006, a bus 1007, etc.

[0265] In the following description, the term "apparatus" can be interpreted as a circuit, a device, a unit, etc. The hardware configuration of the gNB100 and the UE200 may be configured to include one or more of the apparatuses shown in the figures, or may be configured to exclude some of the apparatuses.

[0266] Each function in gNB100 and UE200 is realized by loading specific 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.

[0267] 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 unit 103 and control unit 203 may be realized by the processor 1001.

[0268] Furthermore, 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 programs used are those that cause a computer to execute at least some of the operations described in the above-described embodiments. For example, the control unit 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 programs may be transmitted from a network via a telecommunications line.

[0269] 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 read-only memory (EPROM), an electrically erasable programmable read-only memory (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 communication method according to an embodiment of the present disclosure.

[0270] 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 disc), a smart card, a flash memory (e.g., a card, a stick, a key drive), a floppy 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.

[0271] 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, transmitter 202, etc. may be realized by the communication device 1004.

[0272] The input device 1005 is an input device (for example, 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 (for example, a display, a speaker, an LED lamp, etc.) that outputs to the outside. The input device 1005 and the output device 1006 may be integrated into one device (for example, a touch panel).

[0273] 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.

[0274] Furthermore, 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.

[0275] (Supplementary explanation of the embodiment) 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; features described in two or more items may be used in combination as needed, and features described in one item may apply to features described in another item (unless inconsistent). The boundaries between functional units or processing units in the functional block diagrams do not necessarily correspond to the 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 stations and terminals 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 a base station in accordance with an embodiment of the present disclosure, and the software operated by the processor of a terminal 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.

[0276] <Information notification, signaling> The notification of information is not limited to the embodiments described in the present disclosure, and may be performed using other methods. For example, the 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, the 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.

[0277] <Applicable systems> Embodiments described in the present disclosure may be applied to at least one of a system 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), 6G (6th generation mobile communication system), xG (xG (x is, for example, an integer or a decimal point)), FRA (Future Radio Access), NR (new Radio), New radio access (NX), Future generation radio access (FX), W-CDMA (registered trademark), GSM (registered trademark), CDMA2000, UMB (Ultra Mobile Broadband), IEEE 802.11 (Wi-Fi (registered trademark)), IEEE 802.16 (WiMAX (registered trademark)), IEEE 802.20, UWB (Ultra-Wideband), Bluetooth (registered trademark), or other suitable systems, and next generation systems extended, modified, created, or defined based on these. Furthermore, a combination of multiple systems (for example, a combination of at least one of LTE and LTE-A with 5G) may be applied.

[0278] <Processing procedures, etc.> The order of the procedures, sequences, flowcharts, etc. of each aspect / embodiment described in this disclosure may be changed unless it is consistent. 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.

[0279] <Base station operation> In the present disclosure, a specific operation described as being performed by a base station may 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, but not limited to, an MME or an S-GW). 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.

[0280] <Input / output direction> Information, etc. (see the section on information and signals) 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.

[0281] <Handling of input and output information> Input and output information may be stored in a specific location (for example, memory) or may be managed using a management table. Input and output information may be overwritten, updated, or added to. Output information may be deleted. Input information may be sent to another device.

[0282] <Judgment 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 numerical comparison (e.g., comparison with a predetermined value).

[0283] <Variations of form, etc.> Each aspect / embodiment described in this disclosure may be used alone, in combination, or switched depending on the implementation. Furthermore, 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).

[0284] 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.

[0285] <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.

[0286] 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.

[0287] <Information, Signals> The information, signals, etc. described in this disclosure may be represented using any of a variety of different technologies. For example, data, instructions, commands, information, signals, bits, symbols, chips, etc. that may be referred to throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or magnetic particles, optical fields or photons, or any combination thereof.

[0288] Note that terms explained 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.

[0289] <System, Network> As used in this disclosure, the terms "system" and "network" are used interchangeably.

[0290] <Parameter, channel name> Furthermore, the information, parameters, etc. described in the present disclosure may be expressed using absolute values, may be expressed using relative values ​​from a predetermined value, or may be expressed using other corresponding information. For example, a radio resource may be indicated by an index.

[0291] 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.

[0292] <Base station> In this 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. Base stations may also be referred to by terms such as macrocell, small cell, femtocell, and picocell.

[0293] A base station can accommodate one or more (e.g., three) cells. When a base station accommodates multiple cells, the overall coverage area of ​​the base station can be divided into multiple smaller areas, and each smaller area can be provided with communication service by a base station subsystem (e.g., a small indoor base station (RRH: Remote Radio Head)). The term "cell" or "sector" refers to a part or the entire coverage area of ​​a base station and / or base station subsystem that provides communication service within this coverage.

[0294] In the present disclosure, the base station transmitting information to a terminal may be interpreted as the base station instructing the terminal to control or operate based on the information.

[0295] <Mobile station> In this disclosure, the terms "Mobile Station (MS)," "user terminal," "User Equipment (UE)," "terminal," etc. may be used interchangeably.

[0296] 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.

[0297] <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 object, the mobile object itself, etc. The mobile object refers to a movable object, and may move at any speed. Naturally, this also includes cases where the mobile object is stationary. Examples of the mobile object include, but are not limited to, vehicles, transport vehicles, automobiles, motorcycles, bicycles, connected cars, excavators, bulldozers, wheel loaders, dump trucks, forklifts, trains, buses, handcars, rickshaws, ships and other watercraft, airplanes, rockets, satellites, drones (registered trademark), multicopters, quadcopters, balloons, and objects mounted thereon. The mobile object may also be a mobile object that moves autonomously based on an operational command. It may be a vehicle (e.g., a car, an airplane, etc.), an unmanned mobile object (e.g., a drone, an autonomous vehicle, etc.), or a robot (manned or unmanned). At least one of the base station and the mobile station may be a device that does not necessarily move during communication operations. For example, at least one of the base station and the mobile station may be an IoT (Internet of Things) device such as a sensor.

[0298] Furthermore, a base station in the present disclosure may be read as a terminal. For example, the embodiments of the present disclosure may be applied to a configuration in which communication between a base station and a terminal is replaced with communication between multiple terminals (which may be called, for example, D2D (Device-to-Device) or V2X (Vehicle-to-Everything)). In this case, the terminal may be configured to have the functions of the base station described above. Furthermore, terms such as "uplink" and "downlink" may be read as terms corresponding to communication between terminals (for example, "side"). For example, terms such as an uplink channel and a downlink channel may be read as a side channel.

[0299] Similarly, the term "terminal" in the present disclosure may be read as "base station." In this case, the base station may be configured to have the functions of the terminal described above.

[0300] Fig. 20 shows an example configuration of a vehicle 2001. As shown in Fig. 20, 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.

[0301] 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.

[0302] The electronic control unit 2010 is composed of a microprocessor 2031, a 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).

[0303] 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.

[0304] 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 (outputting) various information such as driving information, traffic information, and entertainment information, and one or more ECUs for controlling these devices. The information service unit 2012 uses information acquired from external devices via the communication module 2013, etc., to provide various multimedia information and multimedia services to the occupants of the vehicle 2001.

[0305] The information service unit 2012 may include input devices (e.g., keyboards, mice, microphones, switches, buttons, sensors, touch panels, etc.) that accept input from the outside, and may also include output devices (e.g., displays, speakers, LED lamps, touch panels, etc.) that output to the outside.

[0306] The driving assistance system unit 2030 is composed of various devices that provide functions for preventing accidents and reducing the driver's driving burden, such as a millimeter-wave radar, a LiDAR (Light Detection and Ranging), a camera, a positioning locator (e.g., GNSS, etc.), map information (e.g., high-definition (HD) map, autonomous vehicle (AV) map, etc.), a gyro system (e.g., an IMU (Inertial Measurement Unit), an INS (Inertial Navigation System), etc.), an AI (Artificial Intelligence) chip, and an AI processor, as well as one or more ECUs that control these devices. The driving assistance system unit 2030 also transmits and receives various information via the communication module 2013 to realize the driving assistance function or the autonomous driving function.

[0307] 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 2029, which are provided in the vehicle 2001.

[0308] 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.

[0309] The communication module 2013 may transmit at least one of signals from the above-mentioned various sensors 2021-2029 input to the electronic control unit 2010, information obtained based on the signals, and information based on input from the outside (user) obtained via the information service unit 2012 to an external device via wireless communication. The electronic control unit 2010, the various sensors 2021-2029, the information service unit 2012, etc. may be referred to as input units that accept input. For example, the PUSCH transmitted by the communication module 2013 may include information based on the above-mentioned input.

[0310] The communication module 2013 receives various information (traffic information, traffic signal information, vehicle-to-vehicle information, etc.) transmitted from external devices and displays it on an information service unit 2012 provided in the vehicle 2001. The information service unit 2012 may be called an output unit that outputs information (for example, outputs information to a device such as a display or speaker based on the PDSCH (or data / information decoded from the PDSCH) received by the communication module 2013). The communication module 2013 also stores the various information received from 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, and the like provided in the vehicle 2001.

[0311] <Terminology and interpretation> 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 in a table, database, or other data structure), ascertaining, 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. 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.

[0312] 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.

[0313] <Reference signal> The reference signal may be abbreviated as RS (Reference Signal) or may be called a pilot depending on the applicable standard.

[0314] <The 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."

[0315] <"First", "Second"> As used in this disclosure, any reference to an element using a designation such as "first," "second," etc. does not generally limit the quantity or order of those elements. These designations may be used in this disclosure as a convenient method of distinguishing between two or more elements. Thus, a reference to a first and a second element does not imply that only two elements may be employed or that the first element must in some way precede the second element.

[0316] <Means> In the configurations of each of the above devices, the "means" may be replaced with a "section", "circuit", "device", etc.

[0317] <Open format> In the present disclosure, when the terms "include", "including" and their variants are used, these terms are intended to be inclusive, similar to the term "comprising". Further, the term "or" used in the present disclosure is not intended to be an exclusive disjunction.

[0318] <Time units such as TTI, frequency units such as RB, 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 referred to as a subframe. A subframe may further be composed of one or more slots in the time domain. The subframe may have a fixed time length (e.g., 1 ms) that does not depend on numerology.

[0319] Numerology may be a communication parameter applied to at least one of the transmission and reception of a certain signal or channel. Numerology 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 configuration, specific filtering processing performed by a transceiver in the frequency domain, specific windowing processing performed by a transceiver in the time domain, etc.

[0320] 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.

[0321] 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.

[0322] 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.

[0323] 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.

[0324] 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. However, the definition of TTI is not limited to this.

[0325] 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.

[0326] 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.

[0327] 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.

[0328] 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 equal to or greater than 1 ms.

[0329] A resource block (RB) is a resource allocation unit in the time domain and 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 also be determined based on numerology.

[0330] 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.

[0331] 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, or the like.

[0332] 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.

[0333] 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 given BWP and numbered within that BWP.

[0334] 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.

[0335] 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."

[0336] The above-described structures of radio frames, subframes, slots, minislots, symbols, etc. are merely examples. For example, the number of subframes included in a radio frame, the number of slots per subframe or radio frame, the number of minislots included in a slot, the number of symbols and RBs included in a slot or minislot, the number of subcarriers included in an RB, the number of symbols in a TTI, the symbol length, the cyclic prefix (CP) length, etc. may be changed in various ways.

[0337] <Maximum transmission power> The "maximum transmit power" in this disclosure may mean the maximum value of transmit power, the nominal UE maximum transmit power, or the rated UE maximum transmit power.

[0338] <Article> 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.

[0339] <"Different"> In the present disclosure, the term "A and B are different" may mean "A and B are different from each other." The term may also mean "A and B are each different from C." Terms such as "separate" and "coupled" may also be interpreted in the same way as "different." [Industrial Applicability]

[0340] One aspect of the present disclosure is useful in wireless communication systems. [Explanation of symbols]

[0341] 10. Wireless communication systems 20 NG-RAN 100 base stations (gNB) 200 User Equipment (UE) 101,202 Transmitter 102,201 Receiver 103,203 Control unit

Claims

1. a control unit that sets a type of repetition opportunity based on whether switching of the type of repetition opportunity of a random access signal is supported; a communication unit that transmits the signal at the opportunity of the type set by the control unit; A terminal comprising:

2. The control unit determines the number of repetitions in the opportunity of the first type before switching the type of the opportunity from the first type to the second type based on parameters set for the first type or the second type. The terminal according to claim 1 .

3. The control unit determines a timing for switching the opportunity type from the first type to the second type based on a first parameter set for a case in which the repetition is performed or a second parameter set for a case in which the repetition is not performed. The terminal according to claim 1 .

4. the control unit determines the number of repetitions in the opportunity of the second type after switching the type of the opportunity from the first type to the second type based on at least one of the number of the opportunities, the number of repetitions in the opportunity of the first type before switching from the first type to the second type, one or more values ​​available for the number of repetitions, a comparison result between communication quality and a threshold used to determine the number of repetitions, and a specific method.

5. a terminal that sets a type of repetition opportunity based on whether or not switching of a type of repetition opportunity of a random access signal is supported, and transmits the signal at the opportunity of the set type; a base station receiving the signal; A wireless communication system having:

6. The device is Setting a type of repetition opportunity based on whether switching of a type of repetition opportunity of a random access signal is supported; transmitting the signal at the opportunity of the set type; Wireless communication method.

Images